AN EVALUATION OP CERTAIN COURSE CONTENT IN RELATION
TO UNDERSTANDING OF PRINCIPLES IN A
BIOLOGICAL SCIENCE COURSE

By
Janes McFarland Elliott

A THESIS

Submitted to the School of Graduate Studies of Michigan
State College of Agriculture and Applied Science
in partial fulflllnent of the requirements
for the degree of
DOCTOR CF EDUCATION
Department of Education

1953

A N EVALUATION OF CERTAIN COURSE CONTENT IN RELATION
TO UNDERSTANDING OF PRINCIPLES IN A
BIOLOGICAL SCIENCE COURSE

By
Janes McFarland Elliott

AN ABSTRACT

Subnltted to the School of Graduate Studies of Michigan
State College of Agriculture and Applied Science
in partial fulfillment of the requirements
for the degree of
DOCTOR car EDUCATION
Department of Education
Tear

Approved

1953

James McFarland Elliott

THESIS ABSTRACT

The purpose or this study- was (1) to obtain an evaluation of the
content of the Biological Science Lecture Syllabus in relation to an
understanding of principles presented in the course and (2) to derive
from these data certain inferences and generalizations having implica­
tions for a) the objectives of Biological Science, b) the "minimum
essentials” concept as it relates to Biological Science, c) the revision
of the Biological Science Lecture Syllabus and the Study Quide for
Biological Science, d) the examination program in Biological Science,
and e) the preparation of laboratory- studies in Biological Science.
A five-place rating scale was employed in obtaining the evalu­
ation of syllabus content.

The staff of the Department of Biological

Science served as the "Jury of ejqpert respondents".

The arithmetic

mean of the ratings which each item received was calculated and assigned
to the item as an index value indicating the degree of contribution
toward an understanding of the related principle. The items related
to each principle were arranged in a frequency distribution on the
basis of index values. Reliability of the rating instrument was deter­
mined by the retake method.

The product-moment coefficient of correla­

tion between the two sets of mean scores for the units of the rating
scale marked a second time were .86 and .75.

The t-test revealed both

coefficients of correlation to be significant at the 1 per cent level
of confidence.

-1-

James McFarland Elliott

Based upon an analysis of the frequency distribution of items of
syllabus content arranged in terms of index values, it was concluded
that the syllabus contains information which contributes in varying
degree toward an understanding of the principles presented in the study
guide.

Furthermore, the staff of the Department of Biological Science,

acting collectively, was able to identify the elements of course con­
tent in the order of the importance of contribution toward an under­
standing of related principles.
The lecture syllabus does not treat adequately, by comparison,
all of the principles presented in the study guide.

Therefore, if

equitable treatment of principles is a desired feature of the syllabus,
the results of this study indicate areas where revision is needed and
also provide information bearing on the general nature of the necessary
changes.
The content of the syllabus does not adequately contribute toward
attainment of the oourse objective "to acquire knowledge of some of the
basic laws (principles) of biology" if it is assumed that this contri­
bution must take the form of adequate contribution by syllabus content
toward an understanding of the principles presented in the study guide.
Until a revision of course material is accomplished the evaluation
of syllabus content obtained as a result of this study should be employed
as a basis for the Investigation of the "minimum essentials" concept
as it related to Biological Science and as a basis for the preparation
of examinations and laboratory studies for use in the biological science
course.

-2-

ACKNOWLEDGMENTS
The author wlehea to extend an expression of
appreciation to Dr. Milosh Muntyan, chairman, and
to his entire guidance committee. The sincere co­
operation of the writer*s own colleagues, who
spent many hours executing the rating instruments
employed in this study, is gratefully acknowledged.

MM MMM MK WM MM
K K M M K MMMM
KM M M Ht'K
KMKKM

•MK*
*

ii

VITA,

Janes McFarland KLliott
candidate for the degree of
Doctor of Education

Final Examinations

May 21, 1953, 8-10 A . M . , 201 Morrill Hall.

Thesis t A n Evaluation of Certain Course Content in Relation to Under­
standing of Principles in a Biological Science Course.

Outline of Studies*
Major Subject*

Higher Education

Cognate Field*

Biological Science

Biographical Items *
Born*

January 19, 1919, Overton, Texas.

Undergraduate Studies* Kilgore Junior College, Kilgore, Texas,
1937-191*0; North Texas State Teachers College, 191*0-191*2.
Graduate Studies* North Texas State Teachers College, 191*6,
Master of Science in Biology, 19l*8j Miohlgan State
College, 191*8-1953.
Experience* Undergraduate teaching assistant, Department of
Biology, North Texas State Teachers College, 191*1-1952j
United States Navy Hospital Corps, 191*2-191*51 Graduate
Teaching Assistant, Department of Biology, North Texas
State Teachers College, l?l*6| Instructor in Biology,
North Texas State Teachers College, 19l*6j Instructor,
Department of Biological Science, Michigan State College,
191*7— .
Member of* Michigan Academy of Science, Arts and Letters,
Alpha Chi (formerly Scholarship Society of the South) ,
Phi Delta Kappa, National Association for Research in
Science Teaching.

TABLE OF CONTENTS
CHAPTER

PAGE

I . THE BACKGROUND OF THE PROBLEM

II.

III.

.....................

1

Introduction.................................
Role of facts in course organisation................
...........................
Origin of the problem
The problem............................................
Statement of the problem....................
Delimitation of the problem.................
Importance of the problem..............
Basic assumptions of the study......................
Organization of the remainder of the thesis...........

1
1
9
17
17
17
18
20
20

REVIEW OF RESEARCH RELATED TO THE PROBLEM................

22

Review of studies illustrating the role of facts in
expressed objectives of general education soience
courses.............................................

2h

Review of studies on course content employing the
"expert jury technique" of evaluation...............

37

METHODS OF PROCEDURE.....................................
Construction of the rating instrument..................
Administration of the instrument..................
Methods of analysis....................................
Determination of reliability.......

IV.

50
50
55
58
61

RESULTS OF EVALUATIONS...................................

63

Method of presenting results................
Interpretation of results.........................
Characterization of the content of the intervals of
the distribution
..................
Relationship of the evaluation of factual content of
the lecture syllabus to the objectives of Bio­
logical Science.....................................
Relationship of these data to the "minimum essentials"
concept..............
Relationship of the evaluation of factual content of
the lecture syllabus to course revision in
Biological Science......................

63
65

Iv

65
Ih
77
81

TABLE OF CONTENTS - Continued
CHAPTER

PAGE
Relationship of the evaluation of the factual
content of the lecture, syllabus to examining
in Biological S c i e n c e ........................
92
Relationship of the evaluation of the factual
oontent of the lecture syllabus .to the preparation
of laboratory studies in Biological Science......
9h

V.

SUMMARY AND CONCLUSIONS...............................

96

96
Summary....................................
Conclusions................
98
Educational i m p l i c a t i o n s ........ 99
Educational implicationsfor Biological Science....
99
Educational implications for Natural Science at
Michigan State College........................ 101
Educational implications for general education
courses............
101
Problems suggested by the study..................... 102
LITERATURE CITED............................................... 106
APPENDIX 1 ..................................................... 110
APPENDIX I I

................................................. 297

v

LIST OF TABLES
TABLE
I.

PAGE
Areas Covered by Instruments9 Length of Instruments in
Pages and Items Together With Portion of Syllabus
Upon Which Each Instrument -was Based.................

I I. Frequency of Items in Respective Intervals of the Index
■Value Distribution for Each Area Unit, Eaoh Principle
and the Combined Totals............

vi

53

86

CHAPTER I

CHAPTER I
THE BACKGROUND OF THE PROBLEM

INTRODUCTION
i

Role of facta In course organisation.

It seems to be generally

agreed that the sciences have a definite contribution to make toward the
objectives of general e d u c a t i o n F o r the most part there is agreement
as to the nature of the contribution, at least to the extent that uni­
formity of expressed objectives can be considered as evidence of such
agreement.
Examination of objectives for biological science courses designed
especially for general education purposes reveals that the factual ele­
ments have not been overlooked.

However, almost invariably the phrasing

of the objectives tends to place emphasis on fundamental principles and
concepts.

It is characteristic of expressed objectives for general edu­

cation science courses that the factual elements of the course are
embodied within the meaning of such an objective a s , for example, "To
• g
become acquainted with seme of the more important facts of science

^E. J. McGrath, Editor. Science in General Education.
Iowa. William C. Brown Company, 1^1*8 . p. 8?.

Dubuque,

Sf. C. Fan Deventer, Chairman, Committee en Research in Junior
College Science, National Association for Research in Science Teaching,
Trends and problems in general education college science courses.
Science Education. 33*89. April 19li9.

2

It is not the intent here to undertake the development of a case
against the emphasis which major principles and concepts have received
in relation to the development of objectives for programs of general
studies. Neither is it to be proposed that the intensity with which
they have been treated be reduced.

What is to be suggested, however,

is that the desire to produce breadth of scope in general education has
resulted to a considerable degree in the failure of factual content to
receive the attention which it deserves. The ter* "factual content" is
used here to refer to course content included within the meaning of the
four senses in which "fact" may
Nagel ?

be used, as differentiated by Cohen and

These four senses in which "fact" may be used are as followst

1. "Fact" may be used to refer to certain discriminated elements
in sense perception.
2. The term "fact" may be used to denote certain propositions
which interpret what is derived by sense experience.
3

.Propositions

which assert an invariable sequence or con­
junction of characters may be within the meaning of "fact".

h. "Fact" may be used to denote those things existing in spaee
or time together with the relations between them, in virtue
of which a proposition is true.
Throughout this study the term "fact" will be used in accord with
the above statements.
General education courses are designed specifically to implement
the objectives of general education programs.

They are intended to

serve as vehicles of progress toward understanding of certain fundamental

^Morris R. Cohen and Ernest Nagel, A n Introduction to Logic and the
Scientific-Method. New York, Harcourt, Brace and Company, 193u. p. 2i?.

3

principles and concepts which have been drawn from the areas to which
a given course pertains.

It is logical to assume that principles and

concepts selected for emphasis should bear a contributory relationship
both to over-all objectives of the program and the objectives of the
course of which they are a p a r t . Thus, it is relatively easy to estab­
lish the relationship between broad principles and concepts of a
designated course and the objectives, both over-all and specific, of a
general studies program.

Indeed, there seems to be general recognition

of the desirability of defining this relationship more specifically.^
Will not extension of the same logic help to establish the relationship
between principles and concepts of an area on the one hand and its
factual content on the other?

Certainly, knowledge of fundamental facts

of an area of learning form the basis for an understanding ef the broader
aspects of the area.

Because this is true, the selection of factual

content for general education merits as much consideration and emphasis
as does the selection of principles, concepts and generalisations.
Attention should be called to the fact that the phrase Knowledge
of fundamental facts of an area and not Knowledge of the fundamental
facts of an area was used in the foregoing passage. The former phrase­
ology was employed specifically to avoid the inference that the point
of view from which this study was undertaken was that only certain
basic facts from an area of study are capable of contributing toward an
understanding of related principles and concepts. The view here is in

^Nathan S. Washton, "A Syllabus in Biology for General Education,"
Science Education. 35*86. March, 1951.

k

accord with the statement in Cooperation in General Education** to the
effect that more than one set of content can be used to attain the ob­
jectives of general education.

For the same reasons, more than one

set of factual material can contribute to an understanding of principles.
The plea is to be made, however, that attention should be given to se­
lection and organization of factual content so that there is ereated in
every course an orderly procession of factual material, each component
of which contributes meaningfully toward understanding of major princi­
ples and concepts.
It is not to be inferred that every item of factual material worthy
of inclusion in a course of study must be capable of standing alone as
a contribution toward the elucidation of the principles, concepts, and
generalizations central to the area.

Indeed, in many instances an item

of factual information may appear as mere minutia when viewed out of
context, yet its role may be vital in completing the mosaic upon which
understanding vests.
It is also desirable to remember that regardless of hew important
a fact may appear when examined in isolation, justification for emphasis­
ing it in the teaching and testing program should be found.

The basic

reason for emphasizing any fact in instructional procedures should arise
from the contribution which the fact in question makes toward an under­
standing of the broader aspects of the course. If the factual content

'’■American Council on Education, Executive Committee on the Co­
operative Study in Qeneral Education, Cooperation in General Education.
Washingtons American Council on Education.
p. 2l£.

5

of a course does not measure up when judged by this criterion, yet
continues to receive instructional emphasis, the indictment that facts
are being taught as isolated phenomena can hardly be avoided.
Factual information should be taught or learned only when it
contributed to the understanding of something. Were the
acquisition of specific items of lnfexmation thus always made
subordinate, there would not be any question of learning too
much factual information, or of learning useless information,
or information that cannot be applied.6
Thus, the solution seems to lie not in the addition of more facts but
in the attempt to identify and incorporate within course structure only
those significant facts which will contribute toward desired understand­
ings .
The belief has been expressed that it should be possible, through
analysis of course structure, to determine the approximate degree of
contribution toward understanding made by certain kinds of facts. To
accomplish this would involve a detailed evaluation of factual content
in terms of criteria derived from principles, concepts, and generalisa­
tions presented in the course. The results would be a determination of
levels of contribution made by different facts toward understanding of
a related principle. Analogous to this view factual content is visualised
as a series of coneentrie circles around a central core of fundamental
or basic ideas, principles, and generalisations which form the nucleus
of course organisation.

The innermost circle is conceived as represent­

ing the factual elements making the most vital contribution toward under­
standing of core materials.

Moving outward, the second circle represents

^James B. Stroud, Psychology in Education. New Terk, Longmans
Green and Company, I n c . 19U6. p. 464*

6

the factual material related to both the factual content of the first
order and to the core material, but the contribution which it makes is
not deemed quite as significant to achievement of desired outcomes as
that made by the material occupying the first orbit.

Thus, following

this analogy, it should be possible to establish a sort of heirarcby of
supporting factual material about the central elements of a course.
As presented, this scheme is suggestive of the modern concept of
the structure of the atom.

Be cognizing this, it is most tempting to

carry the analogy even further by pointing out the parallels that may
be drawn regarding the outermost orbits of both.
It must be admitted that such a conceptualization as has been sug­
gested contains dangerous overtones.

Such a pattern of course organi­

zation could lead to overemphasis on the transmission of factual know­
ledge with the consequent encouragement of rote learning.

Stereotyped

presentation of material and general devitalization of classroom experi­
ences might be concomitants of an attempt to put the scheme into opera­
tion.

But cannot these and other undesirable practices occur under any

plan of course structure?
Basically, whatihas been suggested here is that the factual aspects
of a course of study should be brought into proper focus in the light
of fundamental principles and concepts which have been selected to
enhance attainment of objectives. It is maintained that principles can
be taught only through the medium of facts and that the student learns
and arrives at understanding of principles through a process of synthe­
sis of facts.

It is true that the factual raw materials of understandings

7

may be presented in various w a y s . For example, situations may be
created in which the student discovers the facts for himself, as in the
problem solving approaeh.

The question of importance here is not how

the student gets facts. The concern should be with which facts he gets
and with the use he makes of them.
As further evidence of the relationship between facts and principles,
it is of interest to note the following definitions of principles that
have been offered by various workers.
A principle has been defined b y Washion? as a comprehensive generali­
zation of interrelated facts pertaining to natural phenomena.

He also

states that a principle is scientifically true within the limitations
stated or exceptions noted and that it can be verified by observation
and/or experimentation.
O
Russell defines a principle as follows I
A principle re crystallizes specific judgements into terms having
general application. Thus, if a specific situation can be re­
ferred to as a principle or associated with one, there results
great economy of thought. It becomes unnecessary to form new
opinions or to exercise new judgments. The establishment of a
principle, then, becomes a means of relating large numbers of
meanings and adjusting novel facts as they arise.
Martin

9

defines a principle as a comprehensive generalisation of

interrelated facts, objects, and/or events that must be scientiflcally

7
Nathan S. Washton, o p . c i t .. p. 85.
Q
Charles Russell. Teaching for Tomorrow.
Inc., 1937, p. 1U5.

New York*

Prentioe-Hall

Edgar Martin, nA Determination of the Principles of the Bio­
logical Sciences of Importance for General Education" , Science Education.
29*101, March, 19U5.

8

true with few exceptions.

Observation or experimentation should deter­

mine its true value.
Bergman^ has said that a principle is a scientifically true
generalization which characterizes a fundamental process or structure,
a mode of behavior, or a property pertaining to natural phenomena.
Lawson^* has defined a principle as a relationship or generalisa­
tion that is supported b y such a wealth of data that its truth is very
highly probable. It is also noted that a principle is supported b y so
many observations or facts that the possibility of the discovery of any
facts that disprove it is remote.
Helneman^ describes a principle as a statement of relationship,
frequently causal in nature, between two facts.
All of these definitions, in one way or another, convey the idea
that principles are derived from facts, that the formulation of a
principle is the expression of an interrelationship of facts.

It there­

fore seems logical that the process of teaching for understanding and
application of principles would involve treatment of the basic facts
upon which a given principle rests.

^George J. Bargain, "Determination of Ffcinitplea of Entomology
for General Education11, Science Education. 31*21*, February, 191*7.
^X/hester A . Lawson, Biological Science Lecture Syllabus with
Readings. East Lansing, Michigan* Michigan &tate College #ress,
1951. p. 3.

12

Ailsie M. Heineman, "A Study of General Science Textbooks",
General Science Quarterly. 8*11, Movember, 1928.

\

9

If it is granted that factual material provides the basis for the
teaching-learning situation and if it is accepted that more than one
set of factual material can contribute toward the goals of instruction,
it becomes impossible to escape the implication that the selection of
factual content must be exercised by someone involved in the teachinglearning process.

As most courses are presented the "someone” who

usually makes the selection is the instructor. Frequently, it is not
until examination day that the students discover the facts that the
instructor considered important.

Would it not be more consistent if

basic organisation of the course were carried one step farther in the
beginning and the fundamental factual content were identified immediately
following the determination of significant objectives, concepts, and
principles,?
The literature pertaining to the organisation of courses in bio­
logical science for general education purposes indicates that the
problem of selection of principles has received considerable attention.
Little mention is made, however, eonoernlng the selection of fundamental
facts upon which the principles are based.

It is this interstitial sone,

delimited by objectives on one side and principles and concepts on the
other, that is occupied by the factual elements of course content.

Any

attempt to develop broad courses in a general education program must
involve examination of the content of this interstitial region in
search of facts with which to buttress the generalizations with which
they deal.
Origin of the problem. The general education program at Michigan
State College was introduced in 19k% . The Basic College, responsible

10

for the pro gran, was established as a separate administrative unit com­
posed of seven different departments.

The seven departments were *

Biological Science, Physical Science, Social Science, Effective Living,
History- of Civilisation, Literature and Fine A r t s , and Written and
Spoken English.

According to the committee recommendations resulting

in the establishment of the general education program at Michigan State
College, the function of the Basie College is "to provide students with
a sound foundation on which to build an intelligent interest in personal
family, vocational, social, and civic problems, a better understanding
of these problems, and a greater ability to cope with them... .Students
whose training may eventually become highly specialized need this founds
tion of general educational experience that each may have a greater
appreciation of the relationship of his special field to the needs of
society as a whole.
The Department of Biological Science^* was created in the process
of establishing the Basic College as the vehicle for the general edu­
cation program at Michigan State College.
The biological science course occupies an entire academic year of
three terms. The designations 121, 122 and 123 are used to identify the
first, second and third terms respectively.

The three term sequence is

13

"Report of Committee appointed *For Study and Recommendations1
Concerning Basic Education at Michigan State College." Unpublished
report, Michigan State College, 19iiH«
^ I n the process of reorganisation of the Basic College in 1952,
the number of departments was reduced to four. The Biological Seienoe
Department was dissolved. Virtually the entire staff of the former
Department of Biological Science now comprises the Department of
Natural Science.

11

not comprised of three separate courses, but constitutes one year of
work in the area with considerable continuity between terms.
Students attend two one-hour lecture meetings and one two-hour
laboratory period each week,

Each term of the course is valued at three

credits; the entire sequence at nine credits.

It is possible for the

student to receive credit by moans of passing a comprehensive exmaination in lieu of taking certain terms of the course in class.

Additional

explanation of this point will be presented below in connection with
comment on the testing program.
All three terms of the course have been offered each term of the
academic year.

Students n ay begin the sequence any term during the

year including the summer session.
The average number of students enrolled in the course for the two
year period, 1950 to 1952, was approximately twenty-eight hundred.

Two-

thirds of these were in normal sequence; that is, they were in Basic
121 in the Fall, Basic 122 in Winter and Basie 123 in Spring term.
Throughout the period of this investigation.the staff of the de­
partment consisted ef twenty-two full-time members. The majority of
the staff were teaching through the respective terms in normal sequence
in keeping with the distribution of student lead.

Bach term during

which these ratings were m a de , six or seven instructors were teaching
out of sequence.

This number was required to staff Basie 122 and Basio

123 in the Fall, Basie 121 and Basle 123 in Winter and Basic 121 and
Basic 122 in Spring term.

12

Within the Interval in which this investigation was conducted it
was departmental policy for a given instructor to teach both laboratory
and lecture classes.

Schedules were arranged in such a pay that several

laboratory classes were correlated with specific lecture hours and
instructors were assigned correlated sections.

Thus, students had the

same instructor in both lecture and laboratory classes.

Teaching

assistants within any of the various meanings of the term were net em­
ployed during the period that this study was in progress.
Each instructor was responsible for evaluation procedures in his
own classes while this study was in progress. At the conclusion of
each term the student receives a laborat ory-le c ture grade as determined
by his instructor.

This grade constitutes $0 per cent of the final

grade. The remaining 50 per cent of the tons grade is derived from
performance on a departmental comprehensive examination.
The comprehensive examination is taken b y all students completing
a particular term of the course.

There is a separate examination for

each of the three terms. Net only does the comprehensive evaml nation
provide the criterion for determining

50

per cent of the term grade but

it also provides a means whereby qualified students m ay receive credit
for certain terms of tho course without taking the aetual work in d e s s .
Pertinent to the latter function of the comprehensive examination is
the fact that examinations covering successive terms of work are
"cumulative and increasingly comprehensive". This is understood to mean
that the comprehensive examination covering the first term of the course
contains only first term material while the examination on the second

13

term has selected first term material integrated into its structure.
Examinations on the third term of the course include materials from
both previous terms or work.
A student who achieves a grade of A for the first term of the
course is eligible to apply for permission to take the second term compre­
hensive at the end of his first term of work or he m ay apply for permis­
sion to take both second and third term examinations.

Should he pass

these examinations with a grade of B or better he receives credit for
these terms of work on the basis of his examination grade alone.

The

grade he receives is the same as his letter grade on the examination.
A student in second term may be granted permission to write the third
term comprehensive in event he has a B-plus average for the first two
terms with no grade less than B . If a student receives special permis­
sion to take the comprehensive examination covering any term of the
course and does not achieve a grade of B or better he must take the term
of work in class before repeating the examination.
The Board of Examiners, a department of the Basle College, is
jointly responsible with the departments comprising the Basie College
for the preparation of comprehensive oxaml nations. As experts in test­
ing and evaluation procedures the members of the Beard of Examiners
assume the burden of technical problems concerned with preparation of
comprehensive examinations. The departmental contribution is made through
a committee operating under the joint chairmanship of a representive of
the Board of Examiners and a department member. The remainder of the
committee is composed of regular instructors. The duty of the

departmental examination committee la to write examination questions
and to edit questions written by both the representative of the Board
of Examiners and ether committee members. All comprehensive tests
must be approved by the committee before the final forms of the tests
are published.
In the process of course organisation and development certain
principles, deemed significant to general education, were selected and
included in the course. These principles are clearly indicated either
in the Quide for Laboratory Studies in Biological Science^ or in the
Study Quids for Biological Science. ^
use of a n

They are thus available for the

concerned, staff, examiners and students alike.

the principles about which the course is built.

These are

It is upon the under­

standing and application of these principles that the students are .tested.
They might be termed "minimum essential principles".
The situation is not as clear regarding factual aspects of the ,
course. The objectives of the course"**? mention the acquisition of factual
material as one of the desired outcomes.

A n inspection of the Biological

Science Lecture Syllabus^ appears to justify the conclusion that mash
,

>• y

■

*

• ?, ,

^ S t a f f of the Department of Biological Science, "Quids for
Laboratory Studies in Biological Science". Bast Lansing, Michigan*
Michigan State College Press. 1951. p. 5.
■^Study Quide Committee, "Study Quide for Biological Seienoe".
Bast Lansing, Michigan* Michigan 8tate College Press. 1951.
17
'Education Canalttee, "Objectives for Biological Seienoe” , Unpub­
lished report, Department of Biological Science, Michigan State College,

IB

Chester A. Lawson, l oo , cit.

15

more factual material la Included than Is actually needed for the
formulation of adequate understandings of the principles presented in
the course. This creates the problem of selection on the part of the
student.

Which facts should be mastered to Insure an understanding of

the principles?

For the solution, the student mill look to the Instructor

for guidance.
An analysis of the comprehensive examinations shows that factual
items constitute thirty to sixty percent of the examinations. This im­
plies the problem of selection by the examination committee.
should be included in the examination?

Which facts

Which facts form the basis for

an understanding of the principles of the course?
In teaching it is the policy to emphasise principles.

Principles

are usually explained in terns of the facts upon which they are based.
Which facts should be emphasised in explaining the principles?

This

suggests the problem of selection on the part of the instructor.

The

instructor knows that the comprehensive examinations contain factual
material. A conscientious effort must be made to aid tbs students in
mastery of enough of the material so that they will not be at a disad­
vantage when competing with the students of ether instructors. What is
the basis for the selection of factual material to be emphasised by the
instructor?

This selective process can be performed only in terms of

the application of individual criteria to the vast body of factual ma­
terial at hand.

Different instructors do not apply the same criteria

with the result that different facts are selected for emphasis in the
various classes.

Because one instructor emphasises one factual aspect

16

of a given principle and another may emphasize a different factual
aspect of the same principle, there can be U t t i e agreement between
the two as to what factual elements should be included on the examina­
tion.

An impasse is the result.
Generally » n

instructors are in agreement that factual material

should receive a measure of emphasis in teaching and testing.

All are

more or less in agreement that a student should demonstrate mastery of
certain "fundamental biological facts" before being allowed to leave
the course with a satisfactory mark.

However, upon raising the question

as to which facts should be emphasized in teaching, little agreement
can be obtained.

In the past, attempts by the staff to identify factual

material that could validly be included in the departmental examinations
have resulted in generalisations of little specific value to the examiners.
Recognition of this problem on the part of members of the term-end
examination committee came largely as a result of experiences connected
with the routine functions o f the committee. It was the policy of the
examination committee to work closely with the twenty to twenty-five
individual staff members comprising the department. All items were sub­
mitted to the staff for criticism and were subsequently revised in the
light of such criticism before inclusion in an actual test. Reaction
of st&ff members over the period of years provided a basis for defini­
tion of the problem situation upon which this study is based.

17

THE PROBLEM

Statement of the Problem.

It was the* purpose of this study (1) to

obtain from the staff of the Department of Biological Science an evalu­
ation of the content of the Biological Science Lecture Syllabus relative
to an understanding of principles presented in the course and (2) to
derive from these data certain inferences and generalisations having im­
plications for a) the objectives of Biological Science, b) the "minim um
essentials" concept as it relates to Biological Science, o) the revision
of the Biological Science Lecture Syllabus1? and the Study Quids for
Biological Science, ^ d) the examination program in Biological Science,
and e) the preparation of laboratory studies for Biological Science.
Delimitation of the problem. This study mas limited to an investi­
gation of the relationship between the factual information in the lecture
syllabus and the principles appearing in the study guide.

This limita­

tion was imposed because of the specificity with which the principles
in the study guide were identified with corresponding areas of factual
information in the syllabus.
The content of the Biological Science Lecture Syllabus
this study was not validated against outside criteria.
the syllabus and study guide were official departmental

#1

used in

The fact that
publications

required of all students was presumed to be sufficient evidence that the
contents of the two volumes had received prior validation.
19
^Chester A. Lawson, loc. oit.
Study Guide Committee, l o c . cit.
21Chester A. Lawson, loc. cit.

18

Participation in this study was limited to the staff of the
Department of Biological Science because it mas felt that the judgments
of the individuals actually responsible for the preparation and pre­
sentation of the course were, in the final analysis, the ones of real
significance.
Importance of the problem,

Stroud

22 has pointed out that unless

we can learn to teach more effectively,ra thorough, well rounded,
useful knowledge of facts can be acquired only at the expense of teaching fewer facts. The suggestion to limit the amount of factual material
in a course carries with it the Implication of selection.
facts should be emphasised which meet certain criteria.

Only those
In a course

dedicated to the teaching of major concepts and principles, the criterion
for inclusion of factual material should be based upon the contribution
which knowledge of the facts makes toward understanding of the principles
or concepts to which they are related.

This investigation was under­

taken in an effort to measure the factual content of the biological
science lecture syllabus against this general criterion.

If this objective

can be attained the results of this study should prove useful in the follow­
ing capacities.
1. The results of this study could provide the basis for sub­
sequent revisions of the Biological Science Lecture Syllabus.
2. The results of this analysis would offer a unique reference

22Stroud, l o c . c it .
25
Chester A. Lawson, lo c . cit.

M

19

for use in conjunction with the present methods of planning
and constructing examinations in Biological Science.
3. This study- should make available information pehtinent to the
departmental grading policy.

The contribution in this area

should prove particularly significant in regard to grading
policies based on the "passing grade concept"

2li

since this

study deals to some extent with the identification of "minimum

25

essentials".

k. The results of this study could contribute toward the prepara­
tion of laboratory studies involving methods of science.
5. The information resulting from this study might be utilized as
an aid in the planning of teaching procedures such as lectures,
discussions and visual aids programs.
6. Other colleges and universities using the Biological Science
Lecture Syllabus

26

and/or the Guide for laboratory Studies in

Biological Science2 ^ should be Informed of this study and the
results should be available to then.2®
■

'

i

^Herbert B. Havkes, B. F. Lindquist, and C . S. Mann, The Conatruction and Bae of Achievement Bmmina ti o ns . New Terkt Houghton

Mifflin Company, 1^36.

.

p. 36

2 Ibid.
26chester A. Lawson. Biological Science Lecture Syllabus with
Headings", East Lansing, Miohigan* Michigan State Collage iPress, 1951.
Staff of the Department of Biological Science, loc. ci t .
2®Aocording to information supplied by the Michigan State'College
Press 10 institutions were using the laboratory guide and 3 were using
the syllabus during the Fall of 1952 .

20

Basic as gumptions of this study. The following are the basic
assumptions pertinent to this investigation.
1. Facts for* the basis for teaching and understanding of specific
principles.
2. When a U n i t e d number of faots is employed in teaching a
specific principle certain facts are more important than others
in contributing toward an understanding of the principle.
3. Whfen a limited number of facts is employed in teaching a
specific principle certain facts are essential to an understand­
ing of the principle.
U. The principles appearing in the Study Guide for Biological
Science^ are the principles emphasised by the staff in teach­
ing and testing and by the students in their study.

5 .The judgments of the staff in executing the rating device used
in this study were valid.
6. The fact that the syllabus and study guide were official de­
partmental publications was presumed to be evidence of the
validity of over-all content.
GRQfUnZATION OF ESHMNDER OF THE THESIS
In Chapter II a review of literature related to certain aspects of
the problem is presented.

The first area of the chapter deals with .

studies selected for the purpose of illustrating the changing role of

^ S t u d y Quide Cosmittee, loc. ci t .

21

facts in course objectives. The concluding portion of this chapter
presents a review of studies on selection of eertain course content.
Chapter III explains the procedures employed in this investigation.
The phases described ares

construction of the rating instrument, ad­

ministration of the instrument, analysis of evaluations, and determina­
tion of reliability of the instrument.
Chapter 17 briefly describes the method of presenting the results
of this study but is principally concerned with inferences and generali­
zations derived from the data.
In Chapter V the study is summarized, conclusions are formulated
and educational implications, both specific and general, are considered.
The chapter concludes with further problems suggested by the study.

CHAPTER II

CHAPTER II
REVIEW OF RESEARCH RELATED TO THE PROBLEM

Bullington,1 on the basis of a nation-wide survey of lf>0 general
education science courses, made the recommendation that before content
is selected course objectives should be determined that are in full
agreement with the philosophy of general education and with the policies
of the school.
objectives.

Course content should then be selected in terms of these

The value of this recommendation is evident, since in

practice there should be some structured procedure for the selection of
content, component by component, in terms of the objectives.

It would

be difficult to select the entire content of a course on any other than
a step by step basis and regardless of the plan of selection employed,
some criteria must be utilised in the process.
Examination of the literature discloses the nature of the pro­
cedures that have been utilised as a means of insuring that the course
content is consistent with over-all objectives.

The methods employed

vary in detail but examination discloses a common factor in the entire
group of studies. The common element in the studies reviewed here is
the recognition by the investigators that it is desirable to select
principles, concepts, and generalisations in terms of criteria provided

^Robert Adrian Bullington, "Subject Matter Content of General
Education
Science Courses".» Science Education.
36*285-292. December.
19$2 ^
--------

23

by course objectives.

The view supported here la that the next logical

step In course construction Is to select facts according to criteria
derived from the principles to be presented in the course.

This must

be done before it can be expected that the factual content will be
logically related to the objectives of the course.

The extent of common

thought on this point may appear to be exaggerated because most of the
studies mentioned here deal with selection of principles and not all
general education courses, are "principles1* courses.

Nevertheless, it

is true that such courses are frequently encountered in general eduoa2
tion programs.
Even when other types of courses are employed, the
logic of justifying content in terms of objectives is no less sound than
when applied to the construction of a "principles" course.
Because there is logic in the general practice of looking to ob­
jectives to provide criteria for the selection of immediately subordinate
course components, it may be anticipated that principles and concepts,
once selected, should logically provide criteria governing selection
of course content of lesser stature.

In other words, extension of the

same logic employed in selection of the principles dictates that the
justification for the inclusion of factual material in a course should
arise from the principles and concepts presented.

Furthermore, logic

requires that the facts selected contribute toward an understanding of
the principles and concepts.

Because of the fundamentally simple

nature of the relationships outlined above, it is reasonable to expeat

2Ibid.. p. 286.

21*

that reports of studies dealing with the selection of factual content
in terms of principles could be discovered.

Such is not the ease.

Thorough search has failed to reveal studies dealing specifically with
the problem of selection, or evaluation, of factual content in terms
of criteria derived from stated principles, concepts, and generalise%

tions.

It was recognised before this study was undertaken that there

was this dearth of related material.
Therefore, in the absence of other studies parallel in nature to
the present study, reference will be made to the literature pertaining
to the following points*
1. Studies showing the evolution of the role of facts in
expressed objectives for general education science courses.
2. Studies on the selection of principles for general educa­
tion science courses in which techniques similar to those
used in this investigation were employed.
Review of studies illustrating the role of facts in expressed ob­
jectives of general education science courses. Because of the prominent
role accorded factual material in this investigation, it is probable
that the impression will be created that factual content has been treated
out of proper perspective relative to the other elements of the course.
Since it is true that in courses designed to serve the purposes of
general education facts can be overemphasized, there is Justification
for suspecting that any study devoted to the factual aspects of a course
will be received with marked skepticism in many quarters. T hu s , it should

25

be emphasized again, that this study is an attempt to bring the factual
components of the course in biological science into proper focus with
respect to principles, generalizations, and concepts presented in the
course.

Furthermore> there is a trend toward bringing content into

proper adjustment with other facets of course structure which constitutes
an historical parallel to the development of the general education
point of view in course construction.

The different light in which facts

are regarded may constitute the major point of difference between general
education science courses and those designed primarily for the prepara­
tion of specialists.
The movement toward casting factual material into a role sub­
sidiary to the attainment of other course outcomes is nowhere better
illustrated than in the literature pertaining to course objectives.
Reference to the representative studies from the past two decades re­
viewed below should not only reveal the changing emphasis on factual
content but also the pattern of the change should be relatively clear.
Sequential examination of studies on objectives should also provide
support for the contention that although informational objectives may
no longer receive principal emphasis, the task of bringing facts into
the proper support of other objectives has emerged as a major problem.
Therefore, it is reasonable to believe that the selection of factual
content is more difficult now that facts are expected to make some con­
tribution toward total outcome.
Brief reference will be made to selected studies on objectives
for the purpose of developing the following points t

26

a. That the emphasis on facts as mentioned in stated course
objectives has changed in the past 20 years and that the
pattern of the change can be detected.
b. That the present phraseology of stated objectives implies
a factual content that is subsidiary to the attainment of
the objectives and that a consequence of this is that
factual'content is currently more difficult to select.
Several studies have involved the submission of lists of objectives
to various groups for rating.

In 1931 Berner*' reported a study in which

25 students in a graduate course in Education at the University of Wi s ­
consin were asked to collect lists of/objectives from textbooks, courses
of study and periodicals.

The objectives were then classified according

to knowledges, abilities, habits, appreciations, attitudes, purposes,
ideals, and interest.

In all, 57 distinct objectives were stated.

The class members were then asked to rank each of the objectives by plac­
ing them into five groups. Each objective then received, as its score,
the sum of the ratings given by the class.
est by the class weres

The objectives ranked high­

the habit of scientific thinking, a scientific

attitude, and knowledge which will give insight into the nature and
organization of the enrivoraaent, making it an organized whole instead
of a number of disjointed parts.

This report is mentioned here for

two reasons. First, the technique is basically comparable to the pro­
cedure employed in the present study and, second, the study mentions
acquisition of knowledge as a worthy objective of science instruction,
but qualifies the kind of knowledge and the purpose it is to serve,

^L. M. Berner and others, "Objectives of Science Teaching**, School
Science and Mathematics. 31*550^557, Hay, 1931.

27

that is, knowledge which will give insight into the nature and organi­
zation of the environment.

This suggests that the particular

"knowledges" expected to contribute to understanding of the environment
would have to be related to aspects of the environment.
In 1932 Beauchamp^ conducted an investigation based on an analysis
of stated objectives of science courses aimed at determining frequency
of mention of the various types of objectives.
courses studied were 1*5> courses in biology.

Included in the 160

For courses in biology,

the objectives most frequently mentioned werei

to acquire knowledge that

will produce a better understanding of our environment, to acquire know­
ledge that will lead to more healthful living, to appreciate nature, to
acquire knowledge for worthy use of leisure time, and to acquire know­
ledge of principles of biology.

In four of the objectives mentioned

above reference is made to the acquisition of knowledge Intended to
contribute toward specific outcomes. In the last objective, to acquire
knowledge of principles of biology, the association of factual material
with objectives is unmistakable.

In all five of the objectives the

problem of selection of factual content is implicit.
A report on questionnaires from 68 respondent collegiate institu­
tions teaching science courses of generalised nature was published by
Winokur^ in 1936.

Biological science, physical science and combination

Sfilber L. Beauchamp, Instruction in Science. U. S. Office of Edu­
cation Bulletin, 1932, No. I?, Monograph fro. 42.' Washington* Ooverxnent
Printing Off i c e . 1933. pp. 9-lii.
^Morris Wlnokur, "A Survey of Generalised Science Courses in
Institutions of Higher Education", Science Education. 20*132-li*0,
October, 1936.

28

courses were covered by the study.

The questionnaire contained the

request that the objectives of the courses be given.
each type of objective listed was then tabulated.

The frequency of

The portion of the

results that are of significance for the present study is the fact that
5U of the respondents gave "to teach knowledge of the subject matter of
the course" as one of the objectives.

Burmester^ says, in reference to

the results of this study, "It would appear that in 1938 even in those
colleges courses which are supposedly for the general student the major
emphasis was on the subject matter of science".

Whether or not the

major emphasis was on subject matter during 1936, or in any other year,
is relatively unimportant from the standpoint of the present study.
It is of importance here to point out that when, at any time, instruc­
tional emphasis is on factual content there is the concomitant problem
of selection of facts.

Where progress toward course objectives other

than the informational type is desired, the factual content of the
course will condition attainment of these objectives.

Therefore, those

responsible for the selection of factual content should do so in terms
of criteria which give recognition to other objectives.
7
In 1938 Hard and Jean reported a survey of general education
science courses in colleges dealing with the identification of objectives.
In the questionnaire employed the recipients were asked to indicate the

^iary Alice Buraester, "A Synthesis and Evaluation of Objectives
for Biological Science in the Basic College of Michigan State College".
Unpublished master's thesis, Michigan State College, 19U8, p. 18.
7
*H. 0. Hard and 7. C. Jean, "Natural Science Survey,Courses in
Colleges", Science Education. 22«29U-299, November, 1938.

principle objectives of their course in accord with the following key*
1.
2*
3.
li.

The
The
The
The

acquirement
acquirement
acquirement
acquirement

of
of
of
of

pure science facts.
generalised understandings.
skill in valid and reliable thinking,
socially acceptable scientific attitudes.

Of 209 questionnaires submitted 8U percent were returned.

The first

objective was checked by 35.5 percent of the respondents and 93.1 percent
i

■

.

.

indicated the second objective as the most important.

Apparently some

of the respondents, unable to eheose between facts and understandings,
marked both 1 and 2.

This indicates the difficulties involved in attempt­

ing to separate facts and understandings. Such indecisive behavior may
be attributed to the artificiality of attempting a clear-cut separation
of the two.

It would be more realistic to consider facts and understand­

ings as mutually related factors.
O
Noll, in 1939, reported a study of objectives of science teaching
which was considerably more comprehensive than most similar studies.
In this study a list of objectives was compiled from a total of 130
sources such as textbooks, committee reports, articles, and periodicals.
The objectives thus obtained were then arranged into categories as
follows*

knowledges, abilities, habits, appreciations, attitudes, and

interest.
1

.

*

The findings pertaining to "knowledges" , together with the comments
on this point, are of the most interest in relation to the present study.
Of all categories of objeotives, at all, levels of instruction, the

^Victor H. Noll, The Teaching of Science in Elementary and Secondary
Schools. New ierk* Longmans, (Veen and Company, 19^8. pp. 5-2i.

30

principle emphasis was found to be on "knowledge" . The greatest em­
phasis was at the senior high school level where 51.5 percent of all
objectives listed were in the "knowledges" area.

Noll^ does not believe

that knowledge of facts should be an aim of science but that this kind
of knowledge is a prerequisite to the attainment of the true aims of
science.- These "true alms" are presumed to be such objectives as under%

standing of nature and its organisation, an appreciation of its com­
plexity and orderliness, and so on.

This constitutes recognition of

the foundational role played by facts in the process of gaining under­
standings . Certainly, when knowledge of facts is considered to be pre­
requisite to certain specific understandings, the nature of the under­
standings desired should play' a decisive role in the identification of
the factual precursors.

Noll‘S® also makes a plea for teachers to learn

to think of the purposes of their work in terms of changes to be brought
about in the thinking and behavior of the pupils rather than in terms
of the transmission of facts only.

What is desired la a change of

emphasis from the attempt to transmit mere facts to trying to teach
understandings for which certain faets are prerequisite. The view is
not that facts should be eliminated, but that they should be recognised
in their proper perspective as subsidiary to understandings. Therefore,
it seems that the factual content of a course should be selected in
terms of the understandings desired.

This is the position supported

here and it is also the one from which this study was undertaken.
9
Loc. c i t .
10Holl, op . c i t ., p. 11.

31

Tn

1938,

a questionnaire on science teaching practices was sent

to 100 selected specialists in the field of secondary school science
teaching by the Committee on Secondary Sehool Science of the National
Association for Research in Science Teaching.11

The questionnaire was

comprised of nine main divisions, one of which dealt with the objectives
of secondary school science.

The 71 respondents rated the objectives

on a five point scale ranging fro* great importance, number o n e , to un­
important , number five.

Pro vis ion was made for indicating complete

disagreement with the.objective by checking space X.

Failure to under­

stand the meaning of an objective called for checking space Y.

On this

scale the items relating to the scientific attitude were given the
highest ratings.

Examples of objectives in this category ares

an ob­

jective attitude toward facts, an understanding of cause and effect
relationships, freedom from superstition, and a willingness to suspend
judgment.

The major objective given second highest rating was *!the

ability to think s c i e n t i f i c a l l y T h i r d place was awarded to "mastery
of fundamental knowledges."
It is interesting to note that, once again, the phraseology em­
ployed in expressing the objective awarded first rank is suggestive of
the factual basis of the scientific attitude.

The third place objective,

mastery of fundamental knowledges, leaves some doubt as to its meaning,
because it may be questioned how fundamental knowledges can be identified.
The obtained ratings offer evidence that, at the time of the study,

^ " R e p o r t of Committee on Secondary Sehool Science of the National
Association for Research in Science Teaching", Science Education, 22 1
223-233, October, 1938.
*

32

there was awareness of the desirability of relating factual aspects to
other course objectives.
In 191*3, Hunter and Spore

12

reported a study dealing with evalua­

tions of objectives in which rating scales were used.

In this study 30

objectives were rated as teachers thought they were being taught, not
as they thought they should be taught.

The respondents represented

655 schools. The data were analyzed separately for Junior and senior
high school.

A t both levels the objective which received the highest

rating was "understanding the environment."

Rather than undertake any

subtle means of relating this objective to its obviously factual basis,
it seemar appropriate to question how the environment can be understood
without factual information about i t .

It appears that "understanding

the environment" is an esample of one of the "true aims of Science" the
attainment of which depends on prerequisite facts.
In a monograph, Science in General Education. published in 19l*8,
M cG r a t h ^ summarized materials contributed b y 21 colleges and universi­
ties . Four possible objectives for nen»seienoe major students who take
general education science courses were mentioned.

These m ay be listed

as follows*
1. To understand and learn to use the method of science.
»

,

r

12

Qeorge W. Hunter and Leroy Spore, "The Objectives of Science in
the Secondary Schools of the United States", School Science and Mathe­
matics . 1*3*633-61*7, October, 191*3•
'
Iowa*

13Sarl J. McGrath, Editor. Science in General Education. Dubuque,
tfa. C . Brown and Company, l#i*6.

33

2. To become acquainted with some of the more important facts
of science.
3. To become aware of the social implications of science.
b. To appreciate the historical development of science.
The second objective has definite implications for the problem of
selection of facts for inclusion in any course which attempts to meet
that objective.

Not only would it be necessary to identify the more

important facts of science b u t , consistent with current thinking in
curriculum construction, it would be necessary to select from among
these facts those which contribute toward the attainment of the other
objectives.
In 19U9^* Geer reported the results of a study of objectives for
three survey courses in Physics at the University of Southern California.
At the beginning of the semester 1$0 students were asked to list the
objectives which they considered important for the course. A wide di­
vergence was represented in the opinions of the student respondents.
Hundreds of objectives were listed, which the investigator categorised
by a process of rewording and classification into 21 major objectives.
These were returned to the students with instructions to matte each,
according to the emphasis he believed it should receive.

One hundred

and twenty-one responses were used in the final results.
The method employed by the investigator in arriving at a relative
evaluation of the objectives was to accord "very high" a numerical value

^kyfillard Qeer , "Objectives Students Seek in Physics Survey Courses",
Science Education, 33*152-155, March, 19U9.

3i*

of "li", "high" a value of "3” , etc.

The mean numerical score was then

computed and the objectives arranged In rank order accordingly.
The objective receiving highest rank, with a mean score of 3.38,
was "general knowledge” . The second place mean adore of 2.79 was awarded
to "understanding how mechanical and electrical devices around us work” .
Third position was given to "understanding fundamental laws and princi­
ples" . The results of this study indicate that the "knowledge" type of
objective is still uppermost in the minds of the students.

Inspection

of the objectives also leads to the conclusion that it would be virtually
impossible to devise a teaching program designed to meet any of the
first three objectives without considering the problem of selection of
factual content since the basic criteria for inclusion of factual eon?
tent rest in the objectives.
In addressing a meeting of the science teachers of South Carolina
in 1950, Baker'*''* outlined specific objectives for a program of science
teaching.

The following stands out in its obvious reference to the

problems of selection of factual content for programs of science edu­
cation.
The sciences should give the student a body of accurate, re­
liable and useful knowledge— knowledge which will enable him
to distinguish fact from superstition, education from propa­
ganda .*6
In summarizing the studies on objectives the following points seem
justified*

l5Woolford B . Baker, "Science Teaching and the World of Tomorrow",
Science Education. 3b*7-l5, February, 1950.
l 6Ibid.. p. 11.

35

1. To the extent that stated objectives may be taken as indica­
tive of educational practice, there seems to be a definite trend away
from placing primary emphasis on the transmission of facts as an ob­
jective of generalised science courses.
2. There appears to be a well established movement toward the
practice of attempting to teach certain factual material selected for
the purpose of contributing toward the attainment of other objectives.
3. Increased p irevalence of the point of view expressed in Item 2
above does not mean that facts are caning to be considered as incidental
to learning! that is, something to be tolerated until they can be elimi­
nated at the earliest opportunity.

On the contrary, contemporary ob­

jectives suggest a factual content derived through a prooess of selection
growing out of the realisation that all of the facts can never be covered
in one course and that some facts are more important than others in
contributing toward attainment of concomitant objectives .
U. The results of studies on frequency of mention of objectives
indicate that the teaching of knowledge remains as the objective most
frequently mentioned by all classes of respondents! students, classroom
teachers, and college and university specialists in the teaching of
science.

These findings tend to corroborate the statements in Item 3

above in that they constitute evidence that acquisition of knowledge as
an objective of instruction has not disappeared from the educational
scene.

5.

It is perhaps of general significance to note that the categories

of respondents listed in Item k above (students, classroom teachers,

university specialists) appear in the order of their increasing tend­
ency to qualify the role of facts as course objectives.

Twenty years

ago the college or university specialists probably would have been the
only group to restrict the role of facts as course objectives but at
the present time it can be expected that most classroom teachers will
react approximately the same way.

However, even now, relatively few

students, in a free response situation, will place restrictions on the
part played by facts in course objectives.

This clearly indicates the

time lag that occurs in the dissemination of ideas . The fact that stu­
dents continue to award first place to the acquisition of facts as an
unqualified objective of Instruction probably accounts for muoh of the
student resistance encountered in presenting general education courses
where the principal enphasis is on non-informatlbnal types of objectives.
6.

The phraseology of contemporary objectives for general educatio

science courses indicates that factual content is expected to contribute
toward attainment of many non-informational objectives.

This point of

view may be contrasted with that represented b y the type of traditional
introductory science course Where the primary emphasis is on providing
an introduction to a specialised field.

From the latter point of view,

facts are important because teaching is directed toward the training of
future scientists.

Facts are no less important in the science course

designed for general education purposes but they must be seleoted on a
different basis and restricted in number.

Because of the restrictions

and qualifications arising, for the most part, from the desire to moot
non-informational objectives, it is the contention here that the

37

selection of factual content for general education science courses is
a more rigorous process than would be the case if only informational
objectives were involved.
Review of studies on course content employing the "expert jury
technique*1 of evaluation, A number of studies have been reported in
the past decade dealing, in general, with the identification of princi­
ples desirable for inclusion in the various types of science courses
designed specifically for general education purposes. These studies
have dealt with the problem of selection of principles at both the
senior high school and junior college level.

To a considerable extent,

the common concern of the investigators has been with obtaining relative
evaluations of principles in terms of the criteria or objectives of
general education.

The evident concern over the problem of selection

of principles that are in harmony with objectives of general education
does not, in itself, constitute an indictment, even though it restricts
the investigations to a pattern.

Actually, the concentration on se­

lection of principles indicates a general recognition of at a least one
facet of the over-all problem of course construction.
Another major aspect of the problem of course construction concerns
the selection of course content that will be effectively subsidiary to
the principles, once the principles have been selected.

If it is logical

to assume that principles should be selected in terms of course ob­
jectives , it seems equally logical to assume that the content of the
course that is subordinate to the principles should be selected in terms
of the principles.

38

Thorough search failed to reveal a single study in nhich it was
undertaken to select or evaluate course oontent in terms of principles.
With certain exceptions , to be specifically noted later in this chapter,
the investigators seem to have been content once they had considered
the problem of selection of principles.
The reason for mentioning the studies which will be reviewed below
is because of interest in the techniques of evaluation employed. What
may be called the "jury technique" of obtaining evaluations has apparently
become an accepted practice in educational research.

As a device for

securing evaluations of individual items the "jury technique" offers many
advantages, chief among them being that evaluations obtained by this
method are valid within the limits imposed by the qualifications of the
jurors.
Among the earlier studies in the field of seience education in which
the expert jury was employed for purposes of selecting course oontent was
one reported by W i s e ^ in 19bl.

The investigator was concerned with

determination of the major principles of Physios, Chemistry and Geology
which are of importance for general education.
utilised in four phases of the Investigation.

The jury method was
First, a jury of three

was employed in sorting out duplicate principles from a composite master
list of principles.

Following this operation, the head of the Department

of Physics of the University of Michigan served as a jury of one to check
the surviving principles against the criterion, "It must be true without

"^Harold S. Wise, "The Major Principles of Physios, Chemistry and
Geology of Importance for General Education." Science Education. 25*
371-379, December, 191(1.

39

*

exception or -within limitations specifically stated". The thirds resort
to the jury technique was made when the revised group of principles was
submitted to a jury composed of a specialist in each of the three re­
spective fields involved.

This final submission was for the purpose of

determining accuracy of statement and content of the principles.

Appli­

cations were then assigned to each principle in the composite list and
the applications were checked again by a jury of four specialists.

In

this way a master list of 272 principles together with 3,1^3 applica­
tions assigned to 2l*6 of the principles was obtained.

No conclusions

based on this study alone were presented in the report since it was
pointed out that the conclusions from this study were later synthesized
with those from eleven earlier studies for the purpose of obtaining
composite conclusions.
18
In 19U5 Martin
reported on a study which promises to become a
pioneer educational report of this type.

The study was done for the

purpose of determining the principles of the biological sciences which
are of importance for general education.

The major problem was broken

down into three sub-problems. The first was to determine the important
generalizations of the biological sciences which occur in (l) textbooks
prepared for survey courses in the natural sciences at the junior college
level of the public schools, (2) in textbooks prepared for use in courses
in biology at the secondary level, and (3) in a survey series of the

Edgar Martin, "A Determination of the Principles of the
Biological Sciences of Importance for General Education", Science
Education. 29*100-105, March, 19A5.

1*0

biological sciences prepared for the general reader.

A second sub-

problem was to determine the generalizations of the biological sciences
that appear in the lists of scientific principles in published reports
and in readily available unpublished reports of research studies. The
third'sub-problem mas to determine what are the important major generali­
zations, or principles, of the biological sciences.

The jury technique

was employed in two of the three sub-problems.
In the first sub-problem a committee of three staff members of the
School of Education of the University of Michigan served to provide the
means of selecting three junior college textbooks, three high-school
biology textbooks and a four volume survey series of the biological
sciences to serve as a source of principles.
The jury method was involved in sub-problem three to the extent
that subject matter specialists, one from the Department of Zoology and
the other from the Department of Botany of the University of Michigan,
were asked to improve and refine the statements of principles wherever
necessary and possible.
Finally, a list of 100 major principles was prepared on the basis
of the aggregate of the ranks which each had received in the three evalu­
ations.
value.

The 100 principles were listed in order of their decreasing
Since the time of their publication, these principles have been

mentioned or utilized in almost every study dealing with the identifica­
tion or evaluations of principles.1^

19h . 0. McFadden, "Proposed Integration of Biology Workbook and
Study Materials with Specially Designed Reading Procedures for' the Course",
Science Education. 33tlfj>6, March, 19li9.

la

Also in 19h5, Keeslar

20

reported on the preparation of an original

list of elements of the scientific method and the results of submission
of this list in questionnaire form to a jury of 22 research scientists
at the University of Michigan.

The reactions of this jury of experts

to each element in the list were tabulated and a relative numerical
value based on a 200 point scale was obtained for each element.

Using

the score received by each item on the established scale, all items
falling below a score of 170 were eliminated from the list. The U2 re­
maining items were checked for ambiguity of expression and for errors
by three specialists in the teaching of science. The list, in final
form, consisted of 10 major and 17 minor elements of the scientific
method, set forth in the sequence in which they might be expected to
occur in the solution of a scientific problem involving all 10 major
steps.

The purpose of submitting the list to the 22 experts was to ob­

tain a validation of the entries.

Considerable evidence was presented

to indicate that this was true; that is, that the opinions of the jury
were valid.
Bergnan^**^ published the results of a study in 19U7 in which he

20
Ore on Keeslar, "Contributions of Instructional Films to the Teach­
ing of High School Science", Unpublished doctoral dissertation, University
of Michigan, 19U5. Reported in Keeslar, Qreon, "Objectives of Instruction
in Science", Science Education. 29*212-216, October, 19U5.
21

-‘•George J . Bergnan, "Determination of the Principles of Entomology
of Significance for Qeneral Education. I", Science Education. 31 *23-32,
February, 19U7.
22

George J. Bergnan, "Determination of the Principles of Entomology
of Significance for General Education. II", Science Education. 31*liUi157, March, 191*? .
.

k2

attempted to determine the principles of entomology that have signifi­
cance for general education.

Essentially, the procedure was based on

analyses of books, pamphlets, bulletins, and research articles as
sources of the principles.
in several instances.

The jury method of evaluation was employed

The heads of departments of entomology in nine

colleges and universities servod as Jurors in deciding which textbooks
and reference books used In teaching the fundamentals of entomology were
to be employed as sources of tentative principles. Eleven outstanding
entomologists holding positions either as heads of entomology depart­
ments, as professors of entomology, or as' entomologists with the United
States Department of Agriculture served as critical jurors with respect
to the 1*6 principles of entomology gathered from the forementioned
sources.

A third jury composed of twelve chairmen of high school biology

departments was employed in evaluating the desirability of selected
high school textbooks as sources of biological principles against which
the principles of entomology could be oheoked. In all, three separate
juries were employed for the purpose of evaluating principles, or sources
of principles.

In all instances those selected for jury duty presented

certain qualifications b y virtue of training, experience, or both,
which served to justify the critical role into which they were fitted.
In 19U9, Miles2^ reported another study on the determination of
principles. The purpose of the initial portion of this investigation

2^Vaden W. Miles, "A Determination of Principles and Experiments
for an Integrated Course of Physical Science for High. School. I” ,
Science Education. 33*lU7-15>2, March, I?ii9.

k3

was to determine the relative importance of the principles of physical
science which are desirable for Inclusion In an Integrated course of
physical science for senior high school.
Miles2^ used Wise *s2^ list of 272 principles of physical science
and prepared a rating type of questionnaire which he submitted to five
specialists in the teaching of science , each of whom was well qualified
in terms of experience and subject matter training.

The specialists

were given specific instructions for evaluating each principle in regard
to its desirability for inclusion in an integrated course in physical
science for senior high school.

The rating key employed read as followst

Please write E, D or U at the left of each principle to indicate,
respectively, whether you consider it to be
(1) essential (S) for inclusion in an integrated course
of physical Science for senior high school,
(2) merely desirable (D) if time permits its inclusion, or
(3) undesirable (U) in such a course because it is too
abstract or difficult.
On the basis of independent marking, each principle was assigned
a numerical value which was the sun of the five individual evaluations
of that principle.

A scale was used in which each "essential" designation

was arbitrarily assigned a value of +3; each "desirable" rating was given
a value of +2} and each "undesirable" rating was valued at -2.

All values

received by each principle were added algebraically to give the sum.
The principles were then arranged in descending order of values.
In 19^1, Washton2^ reported on a project concerned with "the pro­
duction of a syllabus in biology for general education, based upon

2^Kiles, l o c. cit.
2% i s e , loo, cit.
2% a t h a n S. Whshton, "A Syllabus in Biology for General Sducation.
I", Science Education. 35*8U-91, March, 1951-

hk

previous invest!gations and current judgments secured from various
leaders in the area of general education and in the biological
sciences".27

In the process of carrying out this project, three prob­

lems uere investigated.

These problems werei

What are the criteria or guiding principles for general education?
What are the significant principles of biology?
What principles of biology have important applications to specific
purposes of general education?
In seeking solutions to the first problem a tentative list of
criteria for general education was prepared from several reports and
studies.

The tentative list was then submitted, in questionnaire form,

to 2f> leaders in the area of general education for the purpose of ob­
taining their responses and comments. Replies were received from 18 of
these specialists.

They were unanimous in their acceptance of 13 criteria

but suggested that 3 more be added.

This was done, making a total of

16 criteria determined on the basis of jury opinion.
28
In determining the principles of biology, Wiashton
started with
Martin*s2^ 100 major principles and, on the advice of a committee of
four subject matter specialists, reduced the number of those principles
to k2 through a process of deletion and combination . The kZ remaining
principles were then subjected to the scrutiny of a group of three
experienced teachers and two laymen, who evaluated the principles in

27Ibid.. p. 81*.
2*Washton, loc. cit.
2^Martin, l o c . cit.

k$

terms of their suitability as objectives of instruction in general
education.

This operation provided the basis for the solution of the

third problem.
The final procedure, preceding actual construction of the syllabus,
was to seek the judgaent of 30 experienced teachers as to which of the
principles of biology they considered most important, important or un­
important to the criteria of general education.

On the basis of the

twenty-five replies received, those principles designated as "most im­
portant* and "important* were included in the syllabus together with
the criterion of general education to which they relate.
The following passage quoted from Washton* s ^ work is also perti­
nent to the present problem.
Students learn principles more efficiently than a vast array
of isolated facts... .Facts become more significant when they
are employed in the processes of deductive and inductive
reasoning to enable individuals to understand principles and
generalizations .31
This appears to embody the basic idea behind the present investi­
gation.

The principles selected for Biological Science were accompanied

by a great number of facts, some directly related to the principles,
some indirectly related, and others unrelated to them.

The present study

is an attempt to bring together principles and related facts within the
framework of an established course.

-^Vashton, loo. cit.
^ N a t h a n S. Washton, "A Syllabus in Biology for General Education.
II” , Science Education. 36*227, October, 1952.

46

A study reported by Smith,

32

in 1951, was concerned with the de­

termination of principles for inclusion in general science at the
junior high school level.

Because of the similarity of procedures which

he employed to those used in the present study brief mention will be
accorded the work here. The jury used in this study consisted of four
Individuals experienced in the field of general science.

30U

They evaluated

principles on the basis of the following three point scale*

+3
+2
-2

■ highly desirable
- desirable
- undesirable

A H scores accorded a given principle were added, giving due
cognizance to the sign.

Thus, one value was obtained which indicated

the importance of the principle as judged by the four evaluators. The
principles were then listed in descending order of relative importance.
33
One of the most recent studies, reported by Irish, ** in 1953>
was undertaken for the purpose of selecting and organizing, from
periodical sources, materials on soil conservation suitable for inclu­
sion in high school science courses for general education.
The initial step was the preparation of a tentative outline of the
various "phases" or "aspects" of soil conservation, which was to serve
as a criterion in locating and identifying conservation materials in

^Herbert F. A. Smith, "A Determination of Principles Desirable
for a Course of General Science at the Junior High School Level",
Science Education. 35*279-284, December, 1951.
Eugene Irish, "A Determination of Materials Dealing with
Soil Conservation and Suitable for Integration into Courses of High
School Science for Qeneral Education", Science Education. 37*84-99,
March, 1953.

1*7

newspapers and magazines. The tentative outline of p h a s e s ” was then
submitted for evaluation to a group of three authorities, all of whom
were professors in the School of Forestry and Conservation of the
University of Michigan.

The validated list of "aspects of conservation"

was then used as the basis for choosing from selected publications
"knowledges of conservation" which were further combined into "major
phases" of soil conservation.
The "major phases" of conservation were then rated by a jury of
five specialists in the teaching of science. Complete directions for
making the ratings were given in the rating device in which the follow­
ing key was used*
Please give each aspect one of the following values.
a. Is essential for inclusion in one of more high
school courses of science.
(value
b. Has some positive value for inclusion in such
courses.
(value
c. Is neither well suited nor poorly suited for
inclusion in courses of high school science. (value
d. Is poorly suited rather than well suited for
inclusion in such courses.
(value
e. Is totally unsuited for inclusion in any high
school science course.
(value

+2)
+l)
0)
-l)
-2)

The values assigned to each of the 1*9 "major phases" of soil con­
servation by the jurors were added giving the algebraic sum.

The

algebraic sum of all five ratings given each "major phase" was considered
as indicative of the general desirability of the "major phase" for inclu­
sion in a high school science course.
Because of an additional step at this point in the survey, the work
of Irislr^ relates more olosely to the present investigation than do
3l*Loc. cit.

h8

some of the other studies mentioned here.

After the determination of

the relative desirability of the "major phases" of conservation, an
attempt was made to relate the desirable "major phases" of conservation
to corresponding principles of the physical and biological sciences.
This was done by arbitrarily assigning each "major phase" to the one
principle to which it made the most apparent contribution. This opera­
tion resulted in a list of the principles of the physical and biological
sciences in which each principle was followed by the related "major
phases" of conservation.

The assignment of "major phases" to correspond­

ing principles was checked for accuracy by two of the specialists from
the original jury.
Summary of studies employing the "eaqaert jury technique" of
evaluation. In summary, the following statements seem to be warranted
regarding the use of the method of the "expert jury".
1. The utilization of the "jury of experts" has apparently become
a well established procedure in educational research.
r■

2. In problems concerned with the selection of course content the
"jury method" has been applied most frequently in the process of obtain­
ing relative evaluations of principles, concepts and generalisations
suitable for inclusion in general education science courses.
3. All studies on the determination of content reviewad here were
based on doctoral investigations. None of the studies were made with
reference to any specific existing course. Therefore, the studies tend
to be generalised in approach.

U9
k . The evaluations obtained by the "jury method" are valid pro­
vided the jurors possess suitable qualifications by virtue of training
and e:xperience, and provided that the criteria upon which the ratings
are to be made are clearly understood.
5. The "jury method", since it is relatively new, undoubtedly needs
refinement.

However, even in its present form it provides a procedure

for securing a concensus upon which decisions may be based.

6. There

is general recognition, on the part of the investigators,

that the principles presented in a course should be selected in accord
with criteria provided by the objectives of the course.

CHAPTER III

CHAPTER III
METHODS QE PROCEDURE

The procedures to be discussed in this chapter ares

(l) construc­

tion of the rating instrument, (2) administration of the instrument,
(3) methods of analysis and

(10

determination of reliability of the

instrument. Each of these phases will be presented consecutively.
Construction of the rating instrument. Basically the problem of
this study was to obtain from the staff of the Department of Biological
Science a Collective evaluation of the factual material contained in the
Biological Science Lecture S y l l a b u s The speoiflc criteria upon which
the evaluations were based were derived from the relationship between
the Biological Science Lecture Syllabus
Science.

2

and Study Guide for Biological

Each student in the course is required to obtain both volumes,

In thC study guide, the objectives and major biological principles of
each course area, as well as a related page assignment in the syllabus

ings.

Chester A. Lawson, Biological Science Lecture Syllabus with ReadEast Lansing, Michigan* Michigan State dollege Press, 1951*
2_
Loc. cit.

^Study Quids Counittee, Study Quids for Biological acience.
East Lansing, Michigan* Michigan 4£tate College frees. 195^•
^Henceforth in this study the Biological Science Lecture Syllabus
and the Study Guide for Biological Science will be referred to respectively as the syllabus and the siudy guide.

51

are presented.

Criteria for evaluating the factual material of the

syllabus were founded upon the assumption that if a student studied a
syllabus assignment he could obtain a factual basis for understanding
of principles included in the area.
Thus, the desire was to create a rating instrument which would
present the entire factual content of the lecture syllabus against a
background of related principles in such a way that each participant
could be asked in substance, "To what extent, if any, does this particu­
lar fact contribute toward an understanding of the related principle?” .
In an effort to achieve this objective a rating device was construct­
ed which followed the organizational pattern of the stucfcr guide. A
separate section of the rating instrument was prepared for each area of
the course^ indicated in the study guide.

Because Area IX of the study

guide does not include a syllabus assignment, no rating device was
prepared for this area.

Presented in Table I is a summary of the titles

of areas covered by each section of the rating instrument together with
the length of the instrument in terms of both pages and items. Also
shown in Table I is the page assignment from the lecture syllabus for
each area.
With the exception of the first unit, each section of the rating
scale was prefaced with identical instructions. The instructions for
the first unit will be described separately later in this section.
was also considered necessary to include in each unit of the rating

''See appendix.

It

52

scale the specific objectives of the area.

If the objectives had been

omitted, It seemed likely that some of the raters might have referred
to the objectives as they* were making judgments while others might not
have done so.

Thus, it appeared wise to insure that all individuals

participating in the ratings read the area objectives along with other
instructions immediately prior to making the actual ratings.
The principal consideration influencing the choice of a scoring
key was the specific nature of the ratings desired.

The rating key

shown below was employed in all of the units of the questionnaire used
in this investigation except in the questionnaire for Area I.

In this

area special conditions made it necessary to use a modified form of the
scoring key shown below.
Mark space 1 if you believe that knowledge of the fact is
essential to an understanding of the principle.
Mark space 2 if you believe that knowledge of the fact is quite
important to an understanding of the principle.
Mark space 3 if you believe that knowledge of the fact is of
average importance to an understanding of the
principle.
Mark space it if you believe that knowledge of the fact is
relatively unimportant to an understanding of
the principle.
Mark space 5 if you believe that knowledge of the fact is
unrelated to an understanding of the principle.
The answer sheet used in this study was the International Business
Machines, Form 1008.

This form was selected because, even though each

sheet is numbered to accommodate only one-hundred and fifty items, re­
numbering of additional sheets for instruments of greater length was
possible.

TABLE I
ARE/IS COVERED BY INSTRUMENTS, LENGTH OF INSTRUMENTS IN PAGES
AND ITEMS TOGETHER WITH PORTION OF SYLLABUS UPON
WHICH EACH INSTRUMENT WAS BASED

Title of Area

Number of
Area

I

The Scientific Approach to Problems

Length in Pages
(Exclusive of
Instructions)

Lengtl
Iter

3.5

60

Characteristics Common to All Living Things

5

n

Transformation of Solar Energy:
Photosynthesis

7

129

v,
Unit 1

Utilization of Matter and Hkiergy*
Foods and Digestion

5.5

Ilk

v,
Unit 2

Utilization of Matter and Energy*
Organ Systems

v,
Unit 3

Utilization of Matter and Energy*
Cells and the Internal Environment

8.5

159

VI,
Unit 1

Coordination and Adjustment*
Nervous Coordination

7.5

159

VI,
Unit 2

Coordination and Adjustment*
Chemical Coordination

i*

97

VII,
Unit 1

Maintenance of the Species*
Reproduction and Development

16

21?

vii,
Unit 2

Maintenance of the Species*
Heredity

12.5

225

VIII,
Unit 1

Interrelationships *
The Organism and Its Environment

21.5

376

VIII,
Unit 2

Interrelationships t
Populations and Conservation

II
III
IV

IX

The Kinds of Living Things

Evolution

Total Pages Exclusive of Instructions
Total Number of Items

11

209

5

76

23

1*27

130

53

TABLE I
COVERED BY INSTRUMENTS, LENGTH OF INSTRUMENTS IN PAGES
AND ITEMS TOGETHER WITH PORTION OF SYLLABUS UPON
WHICH EACH INSTRUMENT WAS BASED

.tie of Area

>roach to Problems

Length in Pages
(Exclusive of
Instructions)

3.5

Length in
Items

&

lg Things
tmmon to All Living Things

Syllabus Assignment
Upon Which Question­
naire was Based

1-5
No Syllabus
Assignment

5

n

5-Hi

7

129

15-17

5.5

Hil

17-21, 31-33

209

33-ltf, 55-63

Solar Energy:
iter and Skiergy:
.on
iter and Energy:

11

iter and Energy:
iemal Environment

8.5

159

1*2-55

adjustment:
iion

7.5

159

63-73

adjustment:
ition

k

97

73-77

> Species:
Development

16

21

78-101*

12.5

225

lOA-138

21.5

376

139-175

5

76

176-216

23

1*27

217-293

?

1Species:
1:
Its Environment

1:
Conservation

notions

130

5k

Analysis of the categories in the rating key shows that the first
category is entirely different from the other four.

When a given

factual item was assigned to this position the raters were thus deeming
it an "essential fact," knowledge of which "is essential to an under­
standing of the related principle."

Category five can be considered

the antithesis of the first position.

Fifth place was selected as the

repository of factual items Which, in the Judgment of the raters, were
so remote from the principle with which they appeared as to make them
unrelated.

Occuring between the two extreme positions, categories two,

three, and four can be thought of as representing relative degrees of
contribution toward an understanding of a given principle.

It is of

singular importance to note that when an assignment was made to any of
the first four categories the raters were admitting that the item being
evaluated was related to the principle with which it appeared and, by
selecting from the first four possibilities, the degree of that relation­
ship was being estimated.
The entire content of the syllabus assignment for a given area
appears in the questionnaire for that area.

None of the factual content

of the syllabus was omitted during the process of preparation of the
questionnaires.

Selection of content was considered to be the preroga­

tive of the Jurors.

Therefore, omission of any of the syllabus content

from the rating instrument would have constituted encroachment on the
province of the raters. The Judgment of all syllabus content was thus
left to the participants.

55

Because no principles were listed for Area I in the study guide,
specific objectives for Area I were utilised in the .construction of
the rating scale for this area.
instructions were necessary.

Because of this variation, different

The following directions and scoring key

were used for Area I only.
It is the purpose of this investigation to discover the relative
importance of the facts included in the Lecture Syllabus for
Biological Science. Bach fact from Area I of the syllabus is to
be evaluated in terms of the contribution which you believe it
makes toward attainment of the specific objectives of Area l .
The specific objectives for Area 1 were taken from the Study
G uide for Biological Science.
The statements to be evaluated
were taken from the syllabus. Will you rate each fact or state­
ment according to the following key?
Hark apace 1 if you believe that knowledge of the fact is
essential to attainment of the objectives.
Mark space
2 if you believe that knowledge of the fact is
quite Important to attainment of the objectives.
Hark space
3 if you believe ”bhat knowledge of the fact is of
average importance to attainment of the objectives.
Hark space
k if you believe that knowledge of the fact is
relatively unimportant to attainment of the
objectives.
Hark space 5 if you believe that knowledge of the fact is
unrelated to the attainment of the objectives.
THE SPECIFIC OBJECTIVES OF AREA I
1. To understand the objectives of general education.
2. To understand the place of biological science in a general
education program.
3. To realise the significance of scientific methods in effective
living.
Administration of the instrument. The twenty-two individuals com­
prising the Department of Biological Science served as the "jury of
experts" used in this study.

Participation was limited to members of

56

the department for a number of reasons.
ment

Bach individual in the depart­

«as thoroughly familiar with course structure, organization, and
/

testing policies.
in the department.

Bach of the jurors had taught at least three years
Average tenure as fall time workers in general

education programs was approximately six years.

Among the raters, 70.k

per cent held doctorates in biological science or related areas.

6

The

remainder were nearing completion of the requirements for the degree.
The personnel of the Department of Biological Science, at the time
these ratings were made, was practically the same group responsible for
the initial preparation of the Biological Science material evaluated in
this study.

Therefore, a "jury of experts" composed of these individuals

should be expected to render judgments exceeding in validity those of
any other group.
There are at least two additional considerations which support the
policy of having limited participation in the study to members of the
department involved.

In the first place, the objective was to secure

the evaluation in terms of criteria provided in the rating instrument.
It was felt that outsiders would have had a strong tendency to evaluate
the principles themselves, instead of limiting their evaluation to the
internal relationships of the course.

Basic to the decision to use

department members as evaluators, was the assumption that principles
contained in the course represented the concensus of the group. To the
extent that this assumption is valid the jury used in this study should

^"Annual Report of the Basie College, 1951-52," Michigan State
College, East Lansing, Michigan.

£7

have been little influenced in their ratings because of subtle dis­
agreement with course principles.
Finally, an Important consideration in favor of having requested
only department members to participate in this study grew out of the
length of the project which participants were asked to carry out.

As

indicated previously, thirteen separate units or sections of the ques­
tionnaire were prepared.

These units ranged in length from three to

twenty-four typewritten pages, the last requiring a total of 1*27 separate
evaluations.

While no check was made to determine the actual time re­

quired of any individual to complete the entire set of questionnaires,
on the basis of random interviews it is safe to assume that many hours
of work went into the operation.

In anticipation of the time that

would be required, it was recognised from the beginning that the
successful completion of this study would depend to a considerable de­
gree upon establishing and maintaining an unusually effective rapport
with those individuals who were asked to contribute to the project.

As

a result of this conviction, the members of the teaching staff of the
i

Department of Biological Science were selected as the group most likely
to give ifccft&hearted support to the endeavor.
Throughout the study all units of the rating scale were distributed
personally to each rater.

When the first unit was delivered, each

individual was carefully informed as to what he was being asked to d o .
and his cooperation was requested.

During the initial contact, however,

the investigator did not interpret the written instructions contained in
the questionnaire.
clear.

It was felt that the instructions were sufficiently

58

The participants were not informed as to the total length of the
evaluative instrument they were being asked to execute.

The feeling was

that advanced knowledge of the magnitude of the task would temper the
enthusiasm of even the most cooperative.

Acting on this belief, the

policy throughout was to collect completed units of the .questionnaire
from each individual and at the same time supply additional units to be
marked.

This resulted in a very close cheek on the progress of in­

dividual raters.

At the same time each was allowed to proceed at his

own speed unburdened by any knowledge of how much work remained to be
done.
The first units of the rating instrument were distributed in
October, 1951, and the last units were completed in June, 1952.

This

represents a much longer time for the completion of the questionnaires
than was anticipated.

In retrospect, however, the time required

appears to be minimal consistent with the preservation of rapport.
Methods of analysis.

It should be clearly understood that what

was desired for purposes of this study was a collective evaluation of
the materials under scrutiny.

It was of no interest, in itself, how an

individual evaluator rated a given factual item but it was of utmost
concern how the group as a whole reacted to the item in question.

Not

only -ma the group reaction of primary concern but it was desired to ob­
tain a means of ranking the items in terms of collective ratings.

This

is but another way of stating that a relative evaluation of factual
content wa* to be achieved if possible.

$9

As & means of facilitating such a comparison it was considered
necessary- to employ a n index number into which the twenty-two separate
ratings which each item received could be translated.

B y means of this

number the group evaluation of one item could be compared with that of
another i t e m .
After experimenting with several possible methods ef obtaining a n
index number , the arithmetic mean was selected as best meeting the re­
quirements . Reco gnition was given to the weaknesses of the arithmetic
mean as a measure of central tendency but in this case it was felt that
the use of the arithmetic mean could be defended.
was low, only twenty-two, and was constant.

The number of eases

The highest possible score

that any item could receive was 5 and the lowest was 1.

The nature of

the rating key and of the material being evaluated made it unlikely
that any one item would receive individual ratings differing from one
another in the extreme.

Finally, the m e a n score would convey approxi­

mately the same meaning for all items, thus offering a fairly reliable
method of comparing the group evaluation of one item with that of
another.
Therefore, the arithmetic mean of the twenty-two separate evalu­
ations for each item in the entire set of rating scales was calculated
to two decimal p l a c e s . The number obtained b y this operation was
assigned to the item as an index number.

Throughout the remainder of

this study the terms "index number 1
1 and "mean score of the item" will
be used interchangeably.

60

Upon obtaining the mean score of the items it became immediately
apparent that a direct comparison of individual m e a n s , each with all
of the others

,

would be both impractical and meaningless.

desired was a grouping of facts of similar index v al u e.

What was

The need for

such groupings will become apparent when it is recalled that the primary
purpose of this study w s
of Biological Science.

to produce results useful to the Department

In a n attempt to achieve the basic goal of

presenting the results of the ratings in such a way as to facilitate
reference to this work, a frequency distribution of items was prepared.
The intervals employed in the frequency distribution were arbitrarily
selected in the interest of furthering the uti 1 itarian nature of the re­
sults obtained b y this investigation.

A n individual using the index

numbers as a basis for detexmlning the relative importance of factual
items would find, in all probability, that as the index numbers approach­
ed unity the desire for finer judgments would arise.

Not only does the

nature of the key used in rating the items tend to make this true, but
the ratings assigned b y the jurors likewise contributed toward creating
the need for finer intervals as smaller index values appear.

The scor­

ing key, it will be recalled, was set up so that "essential to under­
standing" was indicated b y marking space one on the answer sheet.

Sub­

sequent spaces two, three and four were used to indicate decreasing
contribution toward understanding.

Space five, when assigned, indicated

that the fact was considered by the juror as unrelated to the principle
with which it appeared.

The smallest mean score or index number which

an item could have received was one, the largest five.

Therefore,

61

according to the ratings, the closer the Index value approached one,
the more significant the item was in contributing toward an understand­
ing of its related principle.

If the frequency- of index values had

been made with intervals of one, the distribution would have had only
four intervals. This would have resulted in an item with a mean score
of

1.00 falling

into the same interval with an item of mean score 1.99.

This does not discriminate between index values to a sufficient degree
for the ratings to be of practical value.
Determination of reliability. The reliability of the evaluative
instrument used in this study was determined by the retake method.
A unit of the rating scale involving two principles was redistributed
approximately three months after the identical unit had been initially
marked by the raters.

The objective was to determine the correlation

of the mean ratings which a given factual item received on the two
administrations of the scale. The assumption was that a high correlation would indicate high reliability.
Area 7, Unit 2, Principles 1 and 2
selected for repetition.

7

were the sections of the scale

For principle 1, the scale contained 37 items

and for principle 2, 188 items were listed.

The two correlations were

calculated separately using the pro due t-moment method.
of correlation for principle
for principle 2 was .75.

7
See Appendix II.

1

was .86.

The coefficient

The coefficient of correlation

Employing the t-test, both of these coefficients

62

proved to be significant at the 1 percent level of confidence. It is
well to note that in terms of probability, the coefficient of correla­
tion for principle

1

is likely to be spuriously high because of the

fact that the number of capes is small, only

37

items.

CHAPTER IV

CHAPTER IV
RESULTS OF EVALUATIONS

Method of presenting results. The results obtained by calculating
mean scores of Individual Items and then grouping Items receiving mean
scores falling within certain arbitrarily selected Intervals are pre­
sented in Appendix I.

This mode of presentation was adopted for the

purpose of facilitating reference to this investigation.
In Appendix I results of the entire study appear, area by area,
in exactly the same sequence as the corresponding material appears in
the Study Qoide for Biological Science. In compiling the results it
was considered wise, for reference purposes, to preface each unit with
the specific objectives and principles of the unit and to include the
syllabus assignment from which the items were extracted.

In short, the

organizational pattern of the study guide was followed in presenting
the results of this investigation, as well as in constructing the
questionnaires.

In both oases, it was felt that the personnel of the

department, acting initially as jurors and subsequently as consumers
of these results, would find a familiar pattern of organization less
likely to distract from the fundamental purposes at hand.
The frequency of items with a mean soore of 3.51 or higher was found
to be very small.

As indicated by the score, such items were not con­

sidered by the jury as particularly contributory to the principles with

6k

which they appeared.

For this reason, items with a mean score of 3 .51

and higher are indicated in their respective intervals by number only.
The number corresponds to the original number of the item in the
questionnaire.

Content of items indicated in this report by number

only may be obtained by consulting the corresponding questionnaire in
Appendix XX.
All items with mean scores of 3.5*0 or less appear within the inter­
val inclusive of the mean score of the item.

Each item is preceded by

the number assigned to it in the questionnaire, an arrangement which
might prove useful should reason arise to locate a given item within
the parent questionnaire.
The interval delimited by the values 2.51 to 3.50 was the recipient
of items indicated by the Jury to be of average importance in contribut­
ing toward understanding of related principles. All items falling into
this interval are presented in Appendix X, since it was felt that in
most practical applications of the results of this study it would be
necessary to draw heavily upon the material of average importance.
No effort was made to arrange items within intervals in the order
of their index values.

If the results of this stuefy are to have any

practical value, significance must be attached to the fact that a given
item fell within a certain interval with regard do its index value.
No attempt should be made to evaluate relative standing within intervals.
In other words, for the sake of practicality items within a given
interval should be regarded as having the same value.

65

Interpretation of results. The primary undertaking in this study
was to secure a collective, relative evaluation of the factual content
of the lecture syllabus in terms of the principles presented in the
study guide.

The evaluation was to be collective in the sense that it

was to be derived from the composite reaction of a "jury of experts'*
and relative in that it mas to provide a basis for ranking the items
of syllabus content in order ot their respective contribution to under­
standing of related principles.

The results of this effort are pre­

sented in Appendix I . The items of content from the syllabus have been
displayed in terms of levels of contribution derived from categories
of the rating key through combined use of index numbers and a frequency'
distribution.

Since the details of this operation were given in

Chapter III they need not be reoounted here.
It now remains to generalize from these data concerning specific
problem areas associated with Biological Science at Michigan State
College and with other kinds of "principles'* courses.

To the extent

that this can be accomplished the process of securing the evaluation
of syllabus content will have been justified and the results of this
study will assume a significance beyond that of mere tabulated data.
Characterization of the content of the intervals of the distribu—

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tion. In the introductory section of this paper an attempt was made
to show that facts are necessary for an understanding of principles.
It was argued that since facts provide the raw materials from which
understandings of principles are derived, they deserve as much care
in selection as do the principles themselves.

Even if this view is

66

granted,
by

however, there still remains to be established a method where­

selection of factual content can be satisfactorily accomplished in

terms of criteria derived from the principles presented in the course.
The particular method by which it could be expected to select factual
content most likely to contribute toward understanding of principles
would obviously vary in accord with the specific situation.

It should

not be expected that exactly the same procedure of evaluating factual
content could be employed in planning all types of courses nor that the
same detailed approach could be used in selecting materials for a new
course as in revising an existing one.

Indeed, the basic problem may

vary somewhat in character depending upon the task at hand.

If the

problem involves an established course, the investigation nay logically
be limited to an evaluation of existing course materials, for the pur­
pose of bringing factual content into closer support of principles.
On the other hand, if a new course is being organized it may be a
matter of first concern to survey broad areas in search of factual sup­
port for proposed principles.

In the first case the fundamental prob­

lem is embodied in the question, "What is the relative contribution of
facts already in the course toward an understanding of the principles?"
In a project of the latter type concerned with organising a new course
or radical revision of an old one, the problem of imaediate significance
is likely to be found within the meaning of such a question as, "Which
of

the available facts make the greatest contribution toward understand-

ing of the principles?"

The first type of problem requires an answer

in terms of specific facts from sources limited by the scope of the

67

course. An attempt to solve the first type of problem must take the
form of an effort to determine relative levels of contribution made by
different facts toward an -understanding of related principles.

Progress

to-ward solution of the second type of problem could best be served b y a
set of criteria describing the kinds of facts making various degrees
of contribution toward understanding of a related principle.

Such

criteria could then be employed in the selection of desired facts rela­
tive to a given principle from broad areas containing many facts asser­
tively related to the principle.

The result should be an increase in

the degree of relationship between fact and principle.
It is the contention here that the data obtained by this investi­
gation are related to both types of problem situations outlined above.
Since this study involved an established course, it was organized and
conducted within the limits imposed by that fact.

Therefore, the

matter of chief concern was to obtain an evaluation of the content of
the Biological Science Lecture Syllabus for the ultimate purpose of
ranking the factual material into selected levels of contribution toward
understanding of the principles of the course.

In other words, the

attempt was to answer the question, '•What is the relative contribution
of the facts already in the course toward an understanding of the
principles?"
tion.

The data in Appendix I constitute an answer to this ques­

Reference to these data will reveal the level of contribution

of any fact in the lecture syllabus.

The principle ways in which this

information may be utilized as an aid to the solution of problems grow­
ing out of the teaching of the biological science course will be dis­
cussed later in this chapter.

68

Even though the data presented in this chapter were derived from
the study of a specific course, it is possible to generalise from
them toward the development of a set of criteria that might be employed
in recognising the approximate level of contribution toward understand­
ing that could be expected from a fact, examined out of context.

It

may be assumed in the organisation of a new course, or in the drastic
revision of an old one involving the addition of new material, that
it would be desirable to obtain the maximum contribution from factual
content in the support of understandings.

In most courses the scope

is definitely limited in regard to the amount of factual material that
can be, or should be, included.

Therefore, the problem of selection

of factual content cannot be avoided.

Selection must be madej the

dependability of the results depends on two factorst

first, the choice

of a basis for selection and, second, the consistency with which facts
are selected which meet the criteria for inclusion.

The point of view

here is that degree of contribution toward understanding of principles
affords the best basis for selection of factual content for the
"principles*
1 type of course.

Assuming that this basis for selection

has been adopted, it would be difficult to stay within the restrictions
implied by its acceptance unless there were available criteria to aid
in the task.

It is in this capacity as a guide to the recognition of

the desired facts that it is possible to visualise the usefulness of a
description of the factual content of the respective intervals of the
distribution appearing in Appendix I of this study.

If the kinds of

items making the greatest contribution toward understanding of principles

69

can be described in general terras, a means of recognizing such items
in unstructured material will have been indicated and the relationship
of these specific data to the problem of selection of factual content
for a "principles11 type of course in any area will have been partially
defined.
The success of an effort to generalise upon these data in a n at­
tempt to formulate characteristics by means of which desired facts nay
be recognised awaits a positive answer to the following questiont

Is

there a detectable difference in the content of the kinds of items
falling into the various intervals of the distribution corresponding
to the levels of contribution toward understanding?

Study of the dis­

tribution makes it possible to characterise the content of the differ­
ent intervals of the distribution if it is permissible to do so in
terms of generalizations.

To be of value in other areas such character­

izations would have to be in the form of generalizations! therefore the
attempt will be made to describe the content of the intervals in that
manner.
Inspection of the first interval of the distribution, correspond­
ing to the first level of contribution toward understanding of the re­
lated principle, reveals that the items tend toward the definition type
V
of statement. For example, where the principle is Diffusion is the
basic mechanism of transport operating in the physical activities of
organisms assisted by the movements of fluids" a characteristic state­
ment in the first interval is "Diffusion is a process whereby one sub­
stance becomes spread throughout another substance.

In many instances

m

70

the statements seem to involve restatements, in full or in part, of
the principle to which they relate.

In the case of the principle

"Only green plants, those containing chlorophyll, can utilise solar
energy for the manufacture of food" it is found that such statements
as "Green plants have the ability to take the light energy of the sun
and convert it into chemical energy" occupy the first interval of the
distribution.

In this instance the item is an obvious restatement of

the principle.

Items at this level of contribution are characterised

by an almost complete absence of personal judgment.

Items in this

interval tend to be statements of facts that have been accepted for so
long that their validity is seldom questioned.

Perhaps a better may

of phrasing it is that they a r e , for the most part, statements that
i

have withstood repoated testing to the extent that their truth is
highly probable.

In short, the items receiving the highest ratings

in terms of the criteria used are those tested facts from the accepted
content of traditional biology from which the principles of the 'science
have been synthesized.

Those mho may be disturbed b y this finding

because they feel that the use of definitions has little place in teach­
ing for "understandings" should be reminded that the tens "understand­
ings" must be qualified.
to teach?

For "understandings of what" is it desired

If the answer is "for understandings of principles", it is

not surprising that basic definitions (the structural units of under­
standing) should be rated highly in contributing toward that end.

Thus,

these data indicate that knowledge of fundamental definitions related
to the principle makes the greatest contribution toward understanding
of the principle.

71

Characteristic items in the second interval of the distribution
are much like those in the first interval except that they* frequently
contain suggestions of personal interpretation or other evidence of a
lesser degree of unquestioned acceptance in the field of the biological
sciences. In manor oases, the items of the second interval are elabora­
tions -upon or empress an implication of items appearing at the first
level of contribution toward understanding.

If many of the items from

the second interval of the distribution were reworded or condensed so
that their fundamental meaning were more clearly revealed it could be
more readily seen why the jurors rated them highly in terms of contribu­
tion.

For example, the statement "The major endocrine glands of man

are the pancreas, thyroid, parathyroid, adrenal, pituitary, and gonads1
1
appearing in the second interval means, in essence, that the raters
thought that it was of this level of importance to an understanding of
the principle of endocrine coordination and adjustment for the individu­
al to be acquainted with the names of the endocrine glands. In this
respect, of course, rewording of the items in the entire distribution
would serve to clarify meanings for the unfamiliar reader.

In order to

make clear why this was not done, it must be repeated that it was con­
sidered preferable in view of possible practical applications of the re­
sults of this study to leave the results in the language of the syllabus
because of its familiarity to those most likely to use these re stilts.
The third category of the distribution includes items with mean
scores ranging between

2.01 and

2.*>0.

If the items in this interval ean

be characterised at all, it seems to be possible only in terms of items

72

in the first two intervals.

Items making third order contribution, as

evidenced by index numbers, are largely descriptive or they provide
further subdivision of the parent fact appearing in the first or second
interval.

As an example, where the first interval item is "energy

appears in several forms and can be changed from one fora to another" ,
the third category statement is "the energy of motion is called kinetic
energy".
The items indicated by the evaluators to be of "average importance
to understanding" occupy the interval delimited by the index values
2.51 - 3.50.

This is the fourth category of the distribution.

A t this

level of contribution, because of the heterogeneous nature of the items,
it is not possible to characterize the content of the interval accurately
enough for the information to serve as a guide.to the selection of con­
tent in other areas.
What has been said of the fourth interval can also be said of the
fifth interval.

It is not practical to undertake a description of the

content because it is too heterogeneous.
The implications of these data are for "what should be taught" and
not for "how to teach"j that is, the inferences presented here are for
the selection of factual content for a "principles" type of course in
any area and do not concern the method of teaching.
may be summarized as follows t

These implications .

The first three categories of the dis­

tribution of these data indicate that the "jury of experts" believed
that the factual content of a "principles" type of course should be
*

built upon a foundation of .definitions of related terms and upon the

73

tested facts from which the principles have been derived.

There is

further indication that the second and third order contributions to
understanding of related principles are made b y items which tend to be
elaborations upon the definitions and tested facts of the first level.
The evidence suggests the logical process of selection of factual con­
tent described in Chapter II.

This process begins with the selection

of course objectives on the basis of criteria provided b y the objectives
of general education and of the institution, followed b y the selection
of principles in terms of criteria derived from course objectives.

The

selection process should then continue through the selection of factual
content in terms of principles, to the selection of first, second and
third order facts, each in turn being selected on the basis of criteria
provided by those selected in the preceding category.

This relation­

ship may be clarified if it is pointed out that facts making a second
order contribution to understanding of principles should be so selected
as to make that contribution through the medium of their contributory
relationship to some first order content.

The items in the fourth and

fifth intervals, as mentioned previously, are too heterogeneous to
characterize as units. This heterogeneity indicates that unless a
conscious effort is made to maintain a n orderly relationship in course
structure as described above, almost anything can find its way into the
peripheral areas of the course. This is the lesson to be learned from
an examination of the content of the fourth and fifth intervals of the
distribution of items. The material in these intervals serves as a
reminder that the plan of content selection which is adopted must be

7k

pursued
tion

consistently throughout the entire process of course organiza­

or it may be belatedly discovered that the outer orbits of the

course

contain material that is unrelated in the sense that it makes no
to the central intent of the course.

contribution

Relationship of the evaluation of factual content of the lecture
syllabus to the objectives of Biological Science.
Burmester,1

It mas found by

in 19U8, that 76.9 percent of the staff of the Department of

Biological Science felt that "To acquire knowledge of some of the basic
laws (principles) of biology" was one of the "most important" objectives ■
of the course.

It was also found that the other 23.1 percent of the

staff rated the same objective as "quite important* and that none of the
staff rated it as any less important, although provision was made in
the questionnaire for giving three lower ratings.
Assuming that therobjective "to acquire knowledge of some of the
basic laws (principles) of biology" is one of the truly important ob­
jectives in the mind of the staff, it might be expected that an exami­
nation of the data in Table H

would reveal the exbent to which the

staff believes that the syllabus content contributes toward the attain­
ment of that objective.

However, further contemplation on this point

leads to the realization that this expectation depends on certain other
assumptions.
It must be remembered that the evaluations obtained in this study
were

ratings made in terms of specifically stated principles.

Thus,

■Hlary Alice Burmester, "A Synthesis and Evaluation of Objectives
for Biological Science in the Basic College of Michigan State College."
Unpublished master's thesis, Michigan State College, 19li8. P. 38.

75

there

is the possibility that while the staff does feel that the

acquisition of knowledge about basic biological principles is an im­
portant objective, it may not feel that the specific principles appear­
ing in the study guide are the only principles contained in the course,
or that the list includes all of the principles that should be in the
course. It is also possible that some of the principles appearing in the
study guide are principles which the staff feels should not be ini the
course because the syllabus does not offer an adequate treatment of them.
Therefore, basic to the expectation that an analysis of Table II will
reveal the extent of support accorded objectives b y the syllabus, is
the assumption that the principles in the study guide represent the
complete embodiment of the objective, "to acquire knowledge of some of
the

basic laws (principles) of biology *5 that is, that the stated

principles in the study guide represent an adequate selection of princi­
ples within the meaning of the objective.

When attention is called to

the fact that the study guide was prepared after the determination of
the objectives and after the publication of the syllabus, there is no
more reason for assuming that the principles in the study guide represent
the meaning and intent of the objective in question than there is for
assuming that the content of the syllabus represents adequate support
of the principles.
If the assumption is made that the principles in the study guide
represent an adequate selection of principles within the meaning of the
objective to which they relate, then it may certainly be inferred from
the data in Table II that the content of the syllabus falls short, in

s

76

certain areas, of providing adequate clarification and support to the
objective.
Pointing out that this indictment of the syllabus for failing to
support the objectives depends on certain assumptions, does not provide
a basis for dismissing the charge.

The assumptions m a y be tr u e. A n d

even if the assumptions mere false, it would not relieve the obvious
inconsistencies involved in the situation.

The fact that analysis of

these data reveals the existence of this additional area of questionable
relatedness among certain elements of course structure provides a basis
for criticizing one of the basic assumptions of this study.

This basic

assumption is that the principles in the study guide represent the princi­
ples emphasized by the staff in teaching and testing and by the students
in study.
In the preceding discussion, the objective selected for the pur­
pose of illustration was the objective most closely related to this
study.

It would be possible to show the implications of the degree of

relatedness between the syllabus content and other course objectives
less closely allied to this study.

The point has been made, however,

and it is not the intent of this investigation to undertake a study of
objectives.
The position assumed here is that consideration of the relationship
of these data to course objectives provides the most convincing evidence
of the need for thorough reorganization of the content of the lecture
syllabus and study guide.

It is not possible to make the unqualified

statement that much of the syllabus content does not support the

77

objectives of the course. But, it can be said that if the principles
of the study guide constitute the only avenue whereby the content of
the syllabus can contribute to the objectives of the course, much of
the syllabus content does not support the objectives.

This is indicated

by the data in Table II where it can be seen that, with respect to cer­
tain principles, much of the material in the syllabus was assigned to
the fourth and fifth levels of relatedness.

These are levels represent­

ing little contribution toward understanding of related principles.
Relationship of these data to the "minimum essentials1* concept.
In part as an outgrowth of the "passing grade concept," many individuals
have expressed the idea that students should be required to demonstrate
mastexy of certain "minimum essentials" before being allowed to receive
O
a "passing grade" in the course.
A s propounded, this idea usually
embodies behavioral aspects as well as knowledge of certain facts.
is for the latter case that these data have implications.

It

The feeling

has been that students should be required to demonstrate mastery of a
minimum number of essential facts as a prerequisite to receiving a
passing mark.

Implicit in this view is the belief that agreement

could be reached on the content of a list of "minimum essential facts".
Granted that if a list of "essentials" could be prepared it might be
incorporated into grading procedures in an acceptable and beneficial

2
Herbert S. Hawkes, E. F. Lindquist, and C. R. Mann, The Con­
struction and Use of Achievement Examinations. Hew York* Houghton
Mifflin Company, 1^36. p.

m

78

manner, many difficulties still stand in the way of the preparation of
such a list.
mum

The best insurance of success in preparing a list of "mini­

essentials*
1 is full acquaintance with the problems involved.

problems must be defined before they can be solved.

Usually

Study of these

data enables identification of some of the problems connected with the
determination of "minimum essential facts" for Biological Science. To
a limited extent, certain implications for the solution of these prob­
lems are also revealed.

It should be d e a r l y understood that this study

does not represent a perverted attempt to identify "minimum essentials"
for the biological science course although an effort was made in planning
the investigation to design it in such a way that some clarification
of the problem would ensue.

It is now in order to examine the data for

the purpose of discovering if this purpose has been realised.
One of the difficulties involved in identifying "minimum essentials"
was revealed when it was discovered that none of the items falling into
the first interval of the distribution actually received a mean seore
as small as 1.00.

In other words, no single item in any of the units

of the questionnaire was marked as "essential to understanding of re­
lated principle" b y all of the raters composing the jury.
startlingLy different from what should have been expected.

This is not
It is almost

certain that the jurors, as a group, would agree with the statement in
Chapter I that more than one set of factual material is capable of con­
tributing toward an adequate understanding of a given principle.

Because

the syllabus contains many facts, one might expect that units of the
rating scale pertaining to various principles would contain an exness

79

of factual material ranging from unrelated through practically all
levels of relatedness.

No doubt, in some oases it would be possible

to extract from the content of a single unit of the questionnaire two
or more complete sets of factual materials, each set equally capable of
contributing toward the understanding of the principle to which it re­
lates.

To the extent that this is true, a given rater, thinking within

the context provided by one chain of factual support for a principle,
might rate an item as "essential to understanding" while another rater,
thinking within a different context, might rate the same item as some­
thing less than essential.
.£ -

1.^0

at a n

Before an item could fall into the interval

it must have been assigned to the "essential" category

by at least one-half of the twenty-two jurors and designated as "quite
important to understanding" by the other one-half.

This amounts to a n

extremely high standard of agreement required for a n item to fall into
the "essential to understanding" group.

Therefore, the surprising

element in this situation is that as many items as did, fell into the
first interval of the distribution.
It may be concluded that the dearth of material in the first inter­
val is due partly to the small size of the interval and partly to the
high level of agreement necessary before an item would come to occupy
this interval.

It has also been pointed out that more than one adequate

set of items was probably present in each unit of the questionnaire, a
fact which would operate to lower the agreement among the jurors.

A

third reason for the paucity of items in the first interval may have
been a reluctance on the part of the jurors to Indicate any one item

80

as "essential".

Some evidence of this attitude was subjeotively de­

tected during the course of the investigation.

Such a predisposition

might have been partly due to the difficulty of judging the importance
of an item out of context.
At the beginning of this study it was thought that items falling
into the first interval of the distribution, and thereby corresponding
to the first orbit of material about the core of principles would, in
effect, constitute a list of "minimum essentials" for the course.

Xt

is now apparent that, while the items falling into the first interval
only would constitute the beginning of a list, they would not constitute
an adequate list of such "essentials" except by the most limiting
criteria. Because of the high degree of agreement necessary for an
item to fall into the "essential" category employed in this study, there
is considerable justification for lumping the materials of the first
and second intervals into one group as far as the construction of a
practical list of "minimum essentials" is concerned.

Thus, it may be

said that in the first two intervals combined, where the actual index
values ranged from slightly more than

1.00

to

2 .00, may

be discovered

the items that the staff feels are most important to a n understanding of
the principles presented in the course.

A s the foregoing statement

implies, this does not mean that all of the essential items are within
the first two intervals combined nor does it mean that all items in
the combined intervals are essential.

It does seem reasonable to be­

lieve , however, that there is a greater probability that any item within
the combined intervals will approach more closely the status of

81

’•essential", when subjected to other criteria, than any given item out­
side the combined intervals.

This statement immediately raises the

question as to whether the meaning of the term "essential" permits a
relative interpretation.
"essential" or it is n o t .

It may be argued that something is either
It is possible to concede on the point of

definition with the reservation that it be remembered that one set of
factual material may be just as adequately employed in teaching for under­
standing of a principle as another and that a given fact may be "essential"
in terms of one set of facts and "not essential" in terms of a different
set of facts.
Nothing definite can be concluded with regard to identification
of "minimum essentials* on the basis of the results presented h e r e .
Rather, this study is more in the nature of a preliminary investigation
of this particular issue.

The ground has been prepared for further

investigation if such is desired.

In the meantime the relative evalu­

ations obtained in this study offer an alternative that may be employed
in almost any way that a list of "minimum essentials" could be used.
Perhaps the relative evaluations presented here are to be preferred to
a list of "minimum essential" facts because of the overtones of rigidity
inherent in the "minimum essentials* concept.
Relationship of the evaluation of factual content of the lecture
syllabus to course revision in Biological Science. Basic to the de­
cision to undertake this investigation was the belief that an evalua­
tion of the factual content of the lecture syllabus could play a funda­
mental role in the solution of several kinds of problems associated with

82

the course in biological science. The evaluation presented here should
not be considered as an end in itself but as an operation prerequisite
to the more detailed study of specific problems dealing with limited
phases of course organisation and structure.

In substance, tbs evalu­

ations provide a definition, b y the staff, of the internal relationships
of the factual elsments of the course, as they new exist, exclusive of
the laboratory program.

Careful e m « 1 nation of these data should enable

the identification of areas where the degree of mutual relationship
between the factual content of the syllabus and the principles presented
in the stucfcr guide could be improved.

Not only do these data constitute

a means of identifying the areas of weakness in this respect, but they
could serve as the common basis for carrying out a revision of both the
syllabus and study guide for the purpose of improving the relationship
between the two.

While it is not within the province of this investiga­

tion to provide a revision of the lecture syllabus and study guide, it
is an obligation to attempt to show how these data could be useful in
such a project.
Perhaps the most meaningful way in which discussion of the relevance
of these data for course revision can be initiated is by reference to
the analogy on course structure mentioned in the Introductory portion
of this work.

It will be recalled that according to the terms of the

analogy, factual content was visualized as occupying a series of con­
centric circles around the central core of principles forming the
nucleus of course organization.

The concentric circles were interpreted

as levels of contribution toward understending of the centrally located

83

principles.

The factual content of the i n n e m o s t circle was interpreted

as making the greatest contribution and the content of each succeeding
circle was interpreted as making a degree of contribution indicated by
its distance from the center.

Thus, in terns of this analogy, it is

possible to establish categories of facts in terns of the levels of
contribution which they are believed to make toward understanding of
related principles.

That is essentially what was accomplished b y means

of the ratings obtained in this study.

This analogy provides a scheme

into which the factual components of a course may be fitted with the
results that existing lines of relationship are brought more sharply
into focus.

In the process of examining even one aspect of course

structure, such as factual content, the complexity encountered when
interrelationships are considered justifies the use of such a scheme
if it promises to clarify the situation.
The concept of course organisation embodied in the analogy outlined
above has influenced the development of this study since its inception;
therefore, the implications of these data for course revision will.be
discussed within the frame of reference which it provides. For purposes
of orientation within the framework of the analogy, the principles of
the course may be interpreted as occupying the nucleus of course structure.
The evaluative instrument provided the means of establishing orbits or
levels of factual content about the core of principles. The rating key
enabled the jurors to assign items to any one of five categories.

The

first four were categories of relatedness ranging from "essential to an
understanding of related principle" to "relatively unimportant to an

81*
understanding of

the

principle" . The fifth category, "unrelated

understanding of

the

principle", in reality served two purposes.

dual function of

the

unrelated category arose from the fact that

to an
The
in

the constructionof the rating instrument it mas necessary for the
investigator to assign items of factual content to specific principles.
It is probable that some errors in judgment mere m a d e , even though in
cases of doubt items were assigned to more than one principle.

Xt was

assumed that the raters would assign such improperly related items to
category five, thus affording a check on one phase of the construction
of the rating instrument.

The second function of the "unrelated" cate­

gory was to receive items which the individual raters, themselves, be­
lieved should be placed in this category.

Xt cannot be determined which

of these functions was being fulfilled by the "unrelated" category as
a given item was assigned to it b y a rater, nor does it seem to be
necessary to seek this information.

Xt is important to the validity of

the first four categories that the fifth provided a measure of a^|patii
i•

evaluation of the associations between fadt and principle that were made during the process of building the rating instrument.
If the analogous concept of course structure described above is to
prove fruitful, it must be shown how specific data from this study can
be related to the problem of course revision within the terns of the
analogy.

In order to move toward this goal, selected material from the

distribution appearing in the first part of this chapter has been dis­
played in Table XX.

Because of the manner of organisation of the data

in Table XX, new relationships become visible.

The significance of this

study for the problems of course revision lies Within these relationships.

85

Perhaps the most apparent evidence to he derived from a study of
Table II is that there are many empty orbits about certain principles.
This is unmistakable evidence that the syllabus does not give equitable
treatment to all of the principles.

For some of the principles there

is no support at all beyond the first level of contribution.

In the

case of two of -the principles there is no related material in the
syllabus at any level of contribution.

In terms of course revision

this situation seems to call for remedial action.

If the pooriy support­

ed principles are to be retained in the course, additional supporting
material should be added to the syllabus.

1$

it is assumed that the

desire is for closer harmony between the two volumes, the alternative
would be to delete the poorly supported principles from the course.
At the opposite extreme from the principles with many empty orbits,
it can be observed that several of the principles have apparently been
accorded a disproportionately large number of facts, particularly in
the fourth interval of the distribution.
Principle 1 of Area IX.

Notable in this category is

Area VIII, Unitll, Principle h might also be

included in this group, as eould several others. The questions of
significance here might be whether these principles are really overloaded
with supporting facts and whether some of the factual material, therefore,
should be deleted from the course.
of

The overloading of the fourth orbit

a particular prlnoiple relative to the other levels of the same

principle probably arose from the fadt that all material in eaeh syllabus
assignment was assigned to one or another of the principles from the
corresponding area of the study guide when the rating scales were

TABLE II
FRB^UENCT OF TTBSS IN RESPECTIVE INTERVALS OF THE INDEX
VAUJE DISTRIBUTION FOR EACH AREA UNIT, EACH
PRINCIPAL AND THE COMBINED TOTALS

Frequency of Items In Each Interval of
Distribution

33

1
2
3
5

3
3
5
6

CO

22

!

2

S
oS

i

3

u

r*
60
it

1
1
8
Assignment

2

8

1*5

9
70

6

5
it
5
l
2
6
8
3

6
0
1
5
2
1
19
2

3
1
3
It
3
9
1

12

9
6
it
5
it

18
1

26

19

8
1

6
2

it

1

It
12
12

7
36
23
Ut

2
25
2lt
7

19
18

2

o-a

aa

70

O

k

1

15
6

l

6
l

10
8

20

it2

36
6
72
7
it
2k
7
13
9it
77
25
t

l.r*

(c
Principle 2
Principle 3
Area VI, Unit 1
Principle 1
Principle 2
Principle 3
Principle 1*
Area VI, Unit 2
Principle 1
Principle 2
Area VH, Unit 1
Principle 1
Principle 2
Principle 3

7
5

2

1
1
5
2

1
1*
39
10

12
1

30
1*

C.

J.UP
7
7
2

2

5
128

51*
10

28
2

21*

39

11

92
5

1

3
5
ll
29
No Syllabus Assignment

157

11

9
208

Area VII, Unit 2
Principle 1
Principle 2

8
2

ll*
13

8
151*

7
Hi

Area VIII, Unit 1
Principle 1
Principle 2
Principle 3
Principle 1*
Principle 5

5
2
5
ll*
l

9
12
1*
23
18

9
1*
12
39
56

2
3
3

Area VIII, Unit 2
Principle 1
Principle 2

6
6

15
13

22
*

10

9

96
2
11
2

199
1

8

15
13

1*6
10
7
1*

358
13
37
19

263

511

718

761*

83

2339

Area IX
Principle
Principle
Principle
Principle

1
2
3
1*

Totals Each Interval

88
1*2

5

37
188
25
21
2l*

25

189
117
53
23

k

03

o

87

constructed.

In some oases many of the facts were obviously poorly

related to the principle with which they appeared in the rating instru­
ment and probably should have been assigned to the "unrelated" category
by the jurors. Reluctance on the part of the jurors to evaluate any­
thing as "unrelated1
1 undoubtedly resulted in the retention of much
material that should have been eliminated.

It should be noted that the

reference to the reluctance of the jurors to evaluate anything as
"unrelated" is only one possible interpretation. Another interpretation
is that many of the facts in the syllabus, although they may be related
to course objectives, are not provided with related principles by the
study guide. This observation indicates the need for mutual revision
of both syllabus and study guide.
It is aiso apparent from Table II, that the supporting facts in
some instances are limited to the first and second orbits about the
related principle.

As a directive for revision, this can be interpreted

as indicating a need for further scrutiny of this area in the syllabus,,
even though some of the fundamental facts are given.

Elaboration of

these areas of the syllabus for the purpose of including more and broader
faotual coverage is indicated.

Examination of these areas in the syllabus

might also serve to illustrate the nature of a "minimum essential"
treatment of a principle for those who are interested in that problem.
The facts seem to be desirably distributed with regard to some of
the principles, for example; Area IV, Principle li; Area VI, Unit 1,
Principle

3;

and Area VI, Unit

2, Principle

1.

There are no readily

available criteria which can be applied for detexminiag what constitutes

88

desirable distribution but these are examples of what might be con­
sidered acceptable distributions of oontent.

Examination of these

areas in the syllabus during the work of revision should help to develop
ideas that would be helpful in aohievlng improved distribution in problem
areas.
Table II also shows that, in general, there are few "unrelated"
items as indicated by index values.

This moans that there were few

areas where the facts did not fit the principles at some level of re­
latedness.

In this connection it should be recalled that some of the

principles were apparently overloaded with facts at the fourth level of
relatedness.

If this were due to a reluctance on the part of the raters

to assign material to the "unrelated" category, there probably is more
"unrelated" material in the syllabus than the results of the evaluations
indicate.
The last line of Table II contains the distribution of total items.
This distribution might appear to be satisfactory on a course-wide
basisj however, it must be remembered that It conceals inequalities of
the distribution of i t e m related to individual principles. The total
distribution oannot be interpreted as either desirable or undesirable
b e c a m e there is no point of reference upon which to base the judgeent.
Nevertheless, the large number of items placed in categories four and
five indicates the need for a careful weighing of these items before
they are included in a revision of the present syllabus.
Table II presents convincing evidence that revision of course
material would be desirable if theoSfcjJeeiivoiia ^feo br&ng about a closer

89
relationship between study guide and syllabus, but it does not indicate
which volume should be revised. It is the view here that the discrep­
ancies revealed by this study must be regarded as arising from both
.

the syllabus and the study guide.

*

This position is assumed notwithstand­

ing the fact that the syllabus appeared in practically its present form
several years before the preparation of the study guide.
Because the syllabus was published first, 'there might be a tendency
to shift the burden of responsibility for the lack of relationship from
the syllabus to the study guide.

The question might well be asked why

certain principles were included in the study guide when little or no
material related to the principle was to be: found within the syllabus.
Even though the difference in dates of publication may shift some of
the responsibility for the lack of mutual relationship in the direction
of the study guide, it by no -means places all of the responsibility
there.

The study guide includes assignments from other sources as well

as frcm the syllabus and these assignments could justify the inclusion
of some of the principles. To the extent that this is true, it could
be offered as an explanation of why certain principles appearing in the
study guide are poorly related to syllabus oontent.
Both the syllabus and study guide have been revised since the pub*
lication of the study guide but the revisions did not include any
remedial work aimed at increasing the relatedness of the two.

There

were undoubtedly several reasons for not doing so but ehi,ef among them
was the fact that no study of the relationship between the two had been .
made prior to the time of revision.

Because the areks of poor relatedness

90

had not been defined, any improvement in that respect would have been
accidental.
A careful revision of both the syllabus and study guide, eaeh in
terms of the other, offers the greatest opportunity for improvement of
both the course and the books.

There is some basis for the opinion

that a revision directed toward the final incorporation of syllabus
and study guide into one volume offers significant advantages.

Not

the least among the advantages to be gained through combining the
volumes would be the proximity of the stated principles and the support­
ing materials.
The following points may be offered In summary of the implications
of these data for course revision and of the recommendations concerning
such action.
1. The analogy employed in this study provides a medium through
which interrelationships involving facts and principles may be visualized.
The postulated categories of contribution derived from the analogy are
a means of examining content material in respective areas without losing
sight of over-all course organization.
2. As evidenced by the empty orbits of the distribution, the
syllabus does not afford equal factual support for all of the principles
in the study guide.
3. In terms of increasing relationship between the two volumes
there are certain alternative courses of action that may he taken where
principles from the study guide are not adequately supported by the
syllabus content.

These alternatives are to add material to the syllabus,

91

to delete principles from the study guide or to do both.
ll. The fourth interval, corresponding to a key rating of "average
i m p o r t a n c e s e e m s to be overloaded in many cases. This may be due
to a shifting effeot associated tilth calculation of index values, a
reluctance on the part of jurors to assign low ratings, to the fact
that a principle was omitted from the study guide or to a combination
of all three of these factors.
5. The condition referred to in Item U above might be relieved by
adding the appropriate principle to the study guide in the areas where
the fourth orbit of relatedness seems to be overloaded.

The syllabus

content would then have principles to support in those areas where there
is abundant factual material which is now poorly related to the
principles stated in the study guide.

6. Additional

factual materials should be added to the syllabus

in order to better support certain stated principles because these
certain principles have all cf their supporting facts at the first and
second level of contribution.

This constitutes what might be ealled

"minimum essential" support.
7 . Some principles are aeeeptably supported beeause the distri­
bution of facts in the various orbits appears to be above minimal
acceptability.

8. The

total distribution of syllabus oontent can be employed as
«

evidence pertaining to course revision in a limited way.

Although it

may be misleading because it does not take into consideration the much
more important internal distribution of facts relative to individual

92

principles, certain steps for course revision are suggested.

Items

which fell into categories four and five in the distribution should be
carefully evaluated before they are included in a revision of the
present syllabus.
9.

The syllabus provides inadequate support for certain of the

principles in the study guide.
10. Because the syllabus is an avenue by which the most student?
may be reached, it should contain a basic development of all of the
stated principles of the course.
11. A single volume prepared from essential content of the
syllabus and the study guide would be advantageous.
Relationship of the evaluation of the factual oontent of the
lecture syllabus to examining in Biological Science. Referring to the
data presented in Table II, it can be seen that the syllabus contains
large amounts of material pertaining to certain principles and little
or nothing pertaining to ethers. This situation dearly iadioates the
need for mutual revisions of the syllabus and study guide for the purpose
of rectifying the lack of relationship between the two. Until the time
that such a revision beeomes a reality , the examination program must be
based on the textual material in the hands of the students. The question
of significance is whether the results of this study offer a basis for
improving examinations covering the present course material. The answer
to this question is to be found in the validity of the evaluations
obtained as a result of this study.

Since these ratings are valid, the

93

categories of importance thus established provide a criterion against
which factual items proposed for inclusion in examinations should be
checked.
The factual items included in examinations should be largely items
which test for knowledge of those facts making the most significantcontribution to understanding of principles, assuming that understand­
ing of principles is one of the paramount objectives of the course.
In the preparation of departmental examinations it is difficult for
the examination committee to avoid the criticism that items testing
for knowledge of unimportant details, or even for unrelated material,
are included in the examination.

The relative evaluations of factual

content provided by this study should serve as a practical guide for
the examination committee in avoiding errors in judgment which elicit
criticism from the staff.

The evaluations could also be used to justify

the inclusion of items testing for particular facts when the opinions
of one, or a few, of the staff differs from that of the jury regarding
the importance of the facts in question.
Most important of all, the use of the evaluations presented here
j
should aid in the preparation of examinations which/would actually
.

test for knowledge of the basic factual elements of the course as
opposed to the type of examination in which the factual questions are
drawn largely from the peripheral areas of the course.
The importance of the examination in conditioning the attitude of
students toward the course can hardly be overemphasized.

This is

especially true in a course organized as is Biological Science, where

the students take three departmental examinations each year.

Because

the character of the examinations is important, the examination
committee should continuously seek new means of improving them.
this capacity the results of this study can be useful.

In

This study

does not provide the answer to the problem of constructing better,
more valid examinations but the results can contribute toward the
achievement of that objective.
Relationship of the evaluation of factual content of the lecture
syllabus to the preparation of laboratory studies in Biological Science.
In the laboratory program in Biological Science the primary emphasis
is on the methods aspect of science.

There is also concern for teach­

ing understandings of principles and typical laboratory studies actually
deal with method through the medium of principles and related facts.
It has been pointed out that one plan employed in the construction
of laboratory studies for the course has been to select a principle
and then to enumerate as many of the underlying faets as are considered
important to an understanding of that principle.
A n attempt is then made to weave the facts together through the
medium provided by the methods of science, thus building a context in
which the principle is presented.
To the extent that it is the practice to identify important facts
pertaining to selected principles in the process of constructing
laboratory studies, these results could be useful.

The evaluations

presented in this study could serve as reference material for this

99

operation In that they constitute a list of facts evaluated In terms
of contribution to related principles. It should prove valuable to
the individuals engaged in writing laboratory studies to have such a
list available for u se , both as a means of checking selections of re­
lated facts and as a source of ideas for new fact-principle relationships.

CHAPTER V

CHAPTER V
SUMMARY AND CONCLUSIONS
SUMMARY

1. The purpose of this study was to obtain an evaluation of the
faotual material in the Biological Science Lecture Syllabus relative
to an understanding of principles presented in the Study Guide for
Biological Science and to attempt to show the implications of suoh an
evaluation for certain related problems.
2. The criterion upon which the evaluation was based was derived
from the assumption that faotual content of an assignment in the Lecture
Syllabus for Biological Science should contribute toward understanding
of major principles of corresponding areas as they are presented in
the Study Ouide for Biological Science.
3. A rating soale was constructed by means of which the factual
material from the BiologLoal Science Lecture Syllabus was evaluated in
terms of relative contribution toward an understanding of related
principles.
L. Eating instruments covering the entire factual content of the
Lecture Syllabus for Biological Science were submitted to the twentytwo members of the staff ef the Department of Biological Science who
served as the jury of ewperts.

97

5. Based on the twenty-two separate evaluations which each item
received, a mean rating or index value for each item was calculated to
two decimal places.
6. A frequency distribution of index values was prepared employ­
ing intervals arbitrarily selected for the purpose of facilitating
reference to the results of this study.
7. The reliability of the rating instrument was detexminsd by
the retake method.

The two sections of the questionnaire comprising

Area 7, Unit 2 were executed a second time by the jurors after a lapse
of three months.

Coefficients of correlation for the two respective

sets of index values, calculated b y the product-moment method, were
.86 to .7f> respectively.

When subjected to the t-test, both co­

efficients proved significant at the 1 per cent level of confidence.
8. The entire faotual content of the Lecture Syllabus for Biologi­
cal Science was rearranged within the organisational framework pro­
vided to the Study Quids for Biological 8cience while taking into
account the index values received by the factual itwas.
9. Table H

was prepared shewing the number of factual items

assigned to respective levels of eantributlon toward understanding
of each principle presented in the study guide.
10.

From Table U

were derived certain Inferences and generalisa­

tions having implications for the problems of objectives, "minimum
essentials*1, course revision, examining, and preparation of laboratory
studies in Biological Science. A n attempt was made to relate these
data in a general way to the problems of selection of factual oontent
common to "principles* type courses, regardless of area.

98

CONCLUSIONS
On the basis of this study It Is possible to oonolude that, in
the opinion of the teaching staff, the Biological Science Lecture
Syllabus contains facts which contribute in -varying degree toward an
(
understanding of principles presented in the course. Furthermore,
the staff of the Department of Biological Science, acting collectively,
was able to identify the factual elements of the course in the order
of the importance of contribution toward an understanding of principles.
As determined by this study, the lecture syllabus does not treat
adequately, by comparison, all of the principles presented in the study
guide.

It may, therefore, be concluded that if equitable treatment

of principles is a desirable feature of the syllabus, the need for
revision of* both the syllabus and the study guide is indicated.

It

is also concluded that this study not only indicates areas where re­
vision is particularly needed, but that it also provides information
concerning the general nature of the changes.
The conclusion is also reached that the content of the lecture
syllabus does not adequately contribute toward the attaiment of the
course objective

"to aoquire knowledge of some of the basic laws

(principles) of biology •rf*if it is assumed that this contribution
must take the form of an adequate contribution by the syllabus oon­
tent toward an understanding of the principles presented in the study
guide.
Until a revision of the course material is accomplished, the evalu­
ation of syllabus content presented in Appendix I should be utilised

99

in the following ways*
1. As a basis for the investigation of the "minimum essentials"
concept as it relates to Biological Science.
2. In the preparation of examinations in Biological Science.
3. In the preparation of laboratory studies for Biological Science.
Data presented in this study also support the contention that by
means of a detailed analysis of a course of study it is possible to
marshall the factual elements of course content into orderly support
of the major concepts and principles upon which the course is predicated.
EDUCATION IMPLICATIONS
Educational implications for Biological Science. As a result of
the reorganisation of the Basic College at Michigan State College the
Department of Biological Science was officially dissolved on June 30,
1952.

Biological Science will not be taught in the Basio College after

the summer term of 1953.

Instead, a new course, Natural Science, will

be required of all entering freshmen and those transfer students who
cannot satisfy the basic requirement in the science area.
Although Biological Science will no longer be taught at Michigan
State College, a number of institutions will continue to use materials
prepared by the Department of Biological Science and published by the
Michigan State College Press.

Certain of the authors have expressed

a desire to undertake continued revision and improvement of Biological
Science materials now in print, a move which appears to be warranted
in view of the fact that other institutions will continue to use the

100

volumes.

If this project materializes, the results of this investi­

gation should prove significant to its development.
The data presented in this study indicate that revision of both
the Biological Science Lecture Syllabus and the Study Guide for Bio­
logical Science is in order.

The results of this study provide a

partial basis for the revision.

Each volume should be re-examined in

terms of the other j both should be revised in the light of the results
presented in this study.

As a consequence of a revision so prodle^t**,

the factual content of the lecture syllabus could be brought into
closer support of the principles appearing in the study guide.
The evaluations obtained through this study should provide a sig­
nificant contribution to the testing program in Biological Science.
This report presents a consensus of the group responsible for initial
preparation of the textual material -upon uhich this study uas based.
Essentially, it is an expression of their judgment as to the relative
importance of the factual oontent of course materials in terms of
specific criteria.

Therefore, those engaged in the preparation of

examinations covering the material might wish to consult this work.
In regard to the establishment of fixed standards of achievement,
if that is desired, the results of this study should prove especially
useful. In this respect it should be noted that these results constitute
evidence beyond individual opinion and might well serve as the starting
point for investigations on the problem of fixed standards of achieve­
ment, should it be felt that such a problem exists.

101

These results might be utilized as an aid in the organization
of a supplementary reading program for the course.

Where certain

principles from the study guide have been shown by this study to be
poorly or inadequately explained by the syllabus additional readings
might be suggested.
'

*

Educational implications for Hatural Soienoe at Michigan State
College.

Although this study grew out of a specific problem area

encountered in the teaching of Biological Science, the results of this
investigation should have considerable significance for the development
of the new course, Natural Science.

It is reasonable to assume that,

sooner or later, essentially the same problems as those which prompted
the present study will arise in Natural Science.

For example, such

problems as identification of material to be included on examinations,
selection of materials to be emphasized in lecture, and attempts to
establish standards of achievement are almost certain to appear.

There­

fore, the oontent of this study should provide some basis for meeting
problems in Natural Science that are recognised as essentially the
same as those previously encountered in Biological Science.
Educational implications for general education courses. In this
study analysis was confined to the factual oontent of Biological
Science as presented in the general education program at Michigan State
College.

Thus, the usefulness of these specific results is limited.

However, any course designed for general education purposes might benefit
from similar scrutiny.

102

A process of self-evaluation in which the whole staff participates
can be, in itself, the basis for considerable course growth.

This

experience in self-evaluation can be one of critical examination of
course components in relation to objectives, concepts and principles.
Proparly conducted, it can become an activity in w M c h the elements
of the course are evaluated in terras of their contribution to under­
standing and to the progress of students toward ultimate goals.
The final outcome of a study such as this, in any course, might
be elimination of that which fails to meet the test of contribution,
thereby clearing the way for emphasis on those things which do contribute
toward desired outcomes.
In substance, periodic examination of course structure, by these
and similar methods, might be instrumental in reversing what appears
to be a trend toward trying to cover more and more in general education
•

courses and might help to establish instead a policy of attempting to
teach thoroughly and well, a limited amount of carefully selected,
integrated material.
PROBLEMS SUGGESTED BX TEE STUDI
Speculation on specific ways in Which results of this study might
be beneficially applied to Biological Science suggests tbs need for
several additional studies.
The practice of basing grades on the distribution of examination
scores has been questioned b y those who believe that the practice should
be eliminated.

At least two different alternate plans have been proposed.

103

One view Is that fixed standards of achievement should he utilized in
determining grades. Another view is that the distribution of exami­
nation scores should be combined with a minimum standard of achieve­
ment for purposes of determining grades.

In effect, this latter plan

calls for continued use of the distribution of examination scores
but places an arbitrary floor under the curve.
Any realistic effort to Implement either of these plans should be
inaugurated by studies of the problems involved.

The first plan mould

involve a description of course content, carefully and painstakingly
done in terms of exactly what knowledge students would be expected to
demonstrate before receiving a particular letter grade.

In the ease

of the second plan, a no less thorough study of course oontent would
be necessary in order to determine minimum knowledge required before
students would be allowed to "pass the course with a D."

Before either

plan could be placed In operation, even on a trial basis, examinations
would have to be devised covering individual items of course content,
mastery of which would have been deemed "essential11 to certain levels
of achievement.

The work of preparing such examinations should be

preceded by prior indsntifioation of "minimum essentials" corresponding
to desired levels of achievement.

To arrive at identification of

"minimum essentials," it would be necessary to evaluate, in terms of
specific criteria, the entire content of the course.
This study has provided an evaluation of the items of faotual
content in the Biological Science Lecture Syllabus which could serve
as the beginning point for the construction of progressive "minimum

io U

essentials” examinations. The construction of such examinations,
followed by an experimental testing program, might be instrumental in
determining the feasibility of further pursuit of the problem of
"minimum essentials” in relation to grading policy.
type should be undertaken.

A study of this

It offers the possibility of producing

tangible evidence bearing on a problem of the sort which is not likely
to be solved by debate alone.
This study was limited to obtaining an evaluation of the factual
content of the lecture syllabus in terms of contribution to understand­
ing of principles presented in the course in Biological Science. The
method employed was that of the "expert jury."

There remains to be

investigated how the opinion of the jury agrees with student performance.
This information should be obtained.

A study should be done in which

students would be given examinations containing problem situations so
designed that the correct solution would demonstrate knowledge of
and ability to apply the principles presented in Biological Science.
The examinations given the students should a&so-'*contain faotual items
represeubive of the various levels of contribution established b y the
present investigation.

Knowledge of and the ability to apply a particu­

lar principle is generally interpreted as indicating an understanding
of the principle.

Presumably, there should be a positive relationship

between knowledge of factual material deemed contributory to understand­
ing of a principle and the ability to apply the principle in a problem
situation.

It such a relationship could be demonstrated, it could be

offered as further evidence corroborating the use of the "expert jury"

105

technique and would further substantiate the results of this investi­
gation .
The limitations imposed upon this study were such that only factual
material from the Biological Science Lecture Syllabus was evaluated.
Factual oontent is only one facet of Biological Science.

Investigations

should be undertaken for the purpose of discovering the contribution of
the other learning activities in the course toward attainment of ob­
jectives . Both informational and behavorial objectives should be in­
cluded in a project of this type.
Finally, it is strongly recommended that a thorough investigation
of the relationship between the faotual aspects of the biological
science course and the stated objectives be conducted.

A study of this

problem would, in reality, involve analysis of the triangular relation­
ships existing among objectives, principles and factual oontent.

It is

suggested that a promising beginning for an investigation of these re­
lationships would be an attempt to synthesise the results of Burmester *s^
study on objectives for Biological Science with the results of the
present investigation.

•*Mary Alice Burmester. **A Synthesis and Evaluation of Objectives
for Biological Science in the:Basie College at Michigan State College.*
Unpublished master's thesis, Michigan State College, 19k8.

LITERATURE CITED
BOOKS
American Council on Education, Executive Committee on the Cooperative
Study in General Education, Cooperation An General Education.
Washington* American Council on Education. 19A7. 2I4
O pp.
Cohen, Morris R., and Ernst Nagel.
Scientific Method. New York*
i.93h. hfib p p .

A n Introduction to Logie and the
Harcourt. Brace and Company.

Hawks, Herbert E., E. F. Lindquist and C. R. Mann. The Construction
and Use of Achievement Examinations . New York* Houghton
Mifflin Company. 193^>. i»$8 pp.
Lawson, Chester A. Biological Science Lecture Syllabus with Readings.
East Lansing, Michigan* liiohigan State College Press, l9£L.
293 pp.
McGrath, Earl J., editor. Science in General Education. Dubuque,
Iowa* William C. Brown and Company. 19L8. 22lt p p .
Noll, Victor H. "The Teaching of Science in Elementary a n d Secondary
Schools. NewTSork* Longmans, Green and Company.
21R p p .
Russell, Charles. Teaching for Tonefrou.
Inc. 1937. k77 pp.

New York*

Prentice—Hall

Staff of the Department of Biologloal Science. Guide for Laboratory
Studies in Biological Science. East Lansing, Michigan* Michigan
State College ihress. 1951 259 p p •
Stroud, James B. Psychology in Education. New York*
and Company, I n c . 1$1*0•
pp.

Longmans, Green

Study Guide Committee of the Department of Biological Seienoe. Study
Guide for Biological Science. East Lansing, Michigan* Michigan
State College Press. 1951. 1^7 pp.
MONOGRAPHS AND COMMITTEE REPORTS
Beauchamp, Wilber L ., Instruction in Science , U . S . Office of Edu­
cation Bulletin, 1932, N o . 17, Monograph No. 22, Wasgingtowns
Government Printing Office. 1933. P p . 83.

107

Education Committee, "Objectives for Biological S c i e n c e u n p u b l i s h e d
report. Department of Biological Science, Michigan State College,

191*6 .

"Report of Committee on Secondary School Science of the National
Association for Research in Seienoe Education," Science Education.
22*223-233, October, 1938.
"Report of Committee on Research in Junior College Science of the
National Association for Research in Science Teaching," "Trends
and Problems in General Education College Science Courses",
Science Education, 33*172-173, April, 191*9.
PERIODICAL LITERATURE
Baker, Woolf ord B . , "Science Teaching and the World of Tomorrow,"
Science Education. 31**7-15, February, 1950.
Bergman, George J., "Determination of the Principles of Entomology of
Significance for General Education. I," Science Education. 31*
23-32, February 191*7.
Bergman, George J., "Determination of the Principles of Entomology of
Significance for General Education. II," Science Education.
31*11*1*-157, March, 19l*7.
Berner, L. M #, and others, "Objectives of Science Teaching," School
Science and Mathematics. 31*550-557, May, 1931.
Bullington, Robert Adrian, "Subject Matter Oontent of General Education
Soienoe Courses," Science Education. 36*285-292, December, 1952.
Geer, Willard, "Objectives Students Seek in Physios Survey Courses ,"
Science Education. 33*152-155, March, 191*9.
Hard, H. 0., add F. G. Jean, "Natural Science Survey Courses in
Colleges," Science Education. 22*29U-299, November, 1938.
Heineman, Ailsie M., "A Study of General Science Textbooks," General
Science Quarterly. 6*11-23, November, 1928.
Hunter, George W. and Leroy Spore, "The Objectives of Science in the
Secondary Schools of the United States," School Science and
Mathematics. 1*3*633-61*7, October, 19l*3.

108

Irish, E. Eugene, "A Determination of Materials Dealing with Soil Con­
servation and Suitable for Integration into Courses of High School
Science for Qeneral Education.11 Science Education. 3 7*8U-99. March.

1953.

.

“

Keeslar, Oreon, "Contributionsaf Instructional Films to the Teaching
of High School Science,1* Unpublished doctoral dissertation, Uni­
versity of Michigan, 19U5. Reported in Keeslar, Oreon, "Objectives
of Instruotion in Science," Science Education. 29*212; 216,
October, 19k$.
Martin, W. Edgar, "A Determination of the Principles of the Biological
Sciences of Importance for Qeneral Education," Science Education.
29*100-10$, March, 19U5.
McFadden, M. G., "Proposed Integration of Biology Workbook and Study
Materials with Specially Designed Reading Procedures for the
Course," Science Education. 33*156-162, March, 19U9.
Miles, Vaden W . , "A Determination of Principles and Experiments for an
Integrated Course of Physical Science for High School. I," Science
Education. 33*1^7-152, Mareh, 19h9.
Smith, Herbert F. A.', "A Determination of Principles Desirable for a
Course of Qeneral. Science at the Junior High School Level," Science
Education. 35*27U-28it, December, 1951.
Washton, Nathan S., "A Syllabus in Biology for General Education.
Science Education. 35*8U-91, March, 1951.

I,"

Washton, Nathan S., "A Sjyllabus in Biology for Qeneral Education.
Science Education. 36*227-237, October, 1952.

II,"

Winokur, Morris, "A Survey of Qeneralised Science Courses in Institu­
tions of Higher Education.* Se&taoe Education. 20tl32-lL0, October,
1936.
Wise, Harold E., "The Major Principles of Physics, Chemistry and
Geology of Importance for General Education," Science Education.
25*371-379, December, 19i*l.
UNPUBLISHED MATERIALS
"Annual Report of the Basie College, 1951-52." Unpublished report,
Michigan State College, 1952.

109

Burmester, Mary Alice, "A Synthesis and Evaluation of Objectives for
Biological Science, in the Basic College of Michigan State College
Unpublished master** thesis, Michigan State College. 19U8. 128 pp.
"Report of Committee appointed *For Study and Recommendations * Concern­
ing Basic Education at Michigan State C o l l e g e U n p u b l i s h e d
report, Michigan State College, 19UU.

m

APPENDIX I

110

AREA I
The Scientific Approach to Problems
The Specific Objectives
1, To understand the objectives of general eduction*
2* To understand the place of biological science In a general
education program.
3* To realise the significance of scientific methods in effective
living*
The Assignment
Biological Science Lecture Syllabus, pp* 1-5*
MEAN SCORE .0$ - 1*$0
6*

Success of the Individual as a member of society depends upon other
skills and other knowledge (than ability to handle a special task)*
He must know how to cooperate, how to compromise his own particular
needs and desires with those of others for the common good* He must
understand the workings of society and the function of each JLndltidual within it* For this understanding he must know the origin,
growth and development of society* He must appreciate the value of
different parts of society, and above all he must learn to think in
terms of the part he can play In promoting the welfare of mankind*

13*

Uan can learn how his body functions and how his life Is dependent
on matter and -Stterg£ derived from the eakth, from the sun, and from
other living organisms* He can learn the nature of the universal
interrelationships and interdependencies of living things and so
better control them for his benefit* He can learn the nature and
habits of his competitors and he also must learn that to match sue*
cessfully the strength of his competitors he most work with other
members of his group*

15*

Biological Science is designed to give the student an understanding
of basic biological principles so that he may better understand his
own nature and that of all living things*

16*

vith an understanding of his own nature and that of all living things
the individual can live a o n effectively as an individual and as a
member of a group*

17.

A science Is a body of knowledge that Is obtained by means of the
scientific method concerning any part of the universe*

Ill

18. In using the scientific method, one makes observations concerning
natural phenomena.
19*

The results of these observations concerning natural phenomena (data)
axe recorded, classified, and analysed, and from this information
relationships are determined.

29 m

Formulation of an hypothesis is a technique of the scientific method
that aids in the search for relationships or generalisations.

32.

The hypothesis must be tested.

33.

The hypothesis is tested by the collection through observation of
more data that relate to the hypothesis.

3$.

In experimentation the emphasis is on the relationship between cause
and effect. Two similar events are observed, both of which are
exactly alike except for one factor. If the observed results of the
events differ, the difference must have been due to the variable
factor.

37.

If the hypothesis proves incorrect a revaluation of all the facts,
including those brought out in the testing, is made and a new
hypothesis is stated.

UO.

A principle is a relationship or generalisation that is supported
by such a wealth of data that its truth is very highly probable •

1*1.

It must be emphasised that no scientific fact, hypothesis, theory,
or principle is ever proved absolutely ture.

U2.

Scientific truth is a matter of probability.

U 8.

The scientific method may also be used in everyday life.

52.

The scientific method is useful in arriving at opinions that guide
the course of action.

53. In terms of the scientific method the opinion is the hypothesis and
a person trained in this method will be aware of the basis (facts)
an which the opinion (hypothesis) has been made. His degree of con­
fidence in the opinion will vaxy according to the adequacy of the
facts used in its formulation.

5U*

An opinion based on many verified facts will be given more weight
than one without much substantiation.

55*

When an opinion has been accepted it will not be accepted uncon­
ditionally, but further information will be sought in order to
revaluate it (the opinion).

112

58.

A person who uses the scientific method open-midedly has the ability
to view his opinions in the light of facts and is willing to ohaztgs
his opinions in the light of new information* Such a person qlso re­
serves Judgement if after considering the facts he realised that they
are not sufficient for the formulation of an opinion.

61.

The ability to recognise a competent authority and the willingness
to be guided by his opinions are very important factors in living
mors scientifically*
MEAN SCORE 1 *5 1 - 2 .0 0

1.

Man's behavior has been guided since the beginning of human life bgr
two basic requirements, food and reproduction*

3*

Out of primitive man's cooperation with other men grew a complex
society which has evolved into our modern complex civilisation*

5.

Special education is necessary to prepare the individual to do the
special tasks that enable him to satisfy his basic requirements with
the result that there are schools of business, trade schools, schools
of medicine, schools of agriculture and many others*

7*

General education courses teach the skills and knowledge that are
necessary for successful group living*

8*

The welfare of the modern world depends in large measure on the suc­
cess of the general education program in its efforts to teach people
to live together*

9* H a n is a biological organism*
10*

Man's primary activities are biological because without food he
could not live and without reproduction human life would cease to
exist.

11.

ua^ competes with other biological organisms for his food sad fre­
quently for his life* He struggles for his existence Just as other
organisms do*

12*

Man has one advantage not enjoyed by his competitors (in the struggle
for existence)* This advantage is his ability to learn to a greater
extent than any other organsim and to profit by thatnlearning •

1U*

The battle against disease, insects, and erosion is no task for a
single individual* Rather it is a task requiring the united effort
of all the people*

113

20.

The observations (of natural phenomena) to be useful must be made
with great accuracy.

increase the accuracy (of observations)* various measuring devices
. To
are employed and the senses are extended by means of microscopes*

21

telescopes* X-ray machines* and many other instruments.

.

22

Results of the observations (data) axe classified in an orderly
manner.

23.

The order (in the process of classifying data) is developed in
accordance with what man thinks is logical and meaningful.

21*.

In the classification of data facts that appear related are grouped
together.

25.

The classified data are thought over in the search for relationships •

.

26

It is in the search for relationships that the ability to think
logically and brilliantly is of paramount importance.

31.

An hypothesis is made on the basis of too few facts to be accepted
as proved and is no more thus a reasonable guess concerning a pos­
sible relationship that seems to exist.

3U.

The testing of the hypothesis may include experimentation* which is
a controlled observation.

36.

An hypothesis that has been tested may still stand as the best state­
ment of the relationship available or it may be found to be totally
incorrect* in which case it is discarded.

38.

As a third alternative the original hypothesis may be partly correct
and in need only of modification •

39.

A theory is an hypothesis that has withstood repeated tests* but
which has not been tested sufficiently to be accepted as true with
a very high degree of probability.

U3.

The hypothesis* being based on a few facts only* has the least chance
of being a true statement of relationships. Further observation may
easily show that the hypothesis is untenable.

1*5.

The principle (law or doctrine) has the greatest chanoe of surviving
as a statement of relationships among natural phenonsna beoauss it
is the result of the accumulation or years of repeated observations
and tests ty many scientists.

nU

U6.

Because there are so many observations or facts that support the
principle* the possibility that any facts will ever be discovered
that disprove it is remote*

U7.

it should be remembered also that the relationships are man-made
and are what aeen to be logical explanations of the observed
phenomena of nature*

U9«

Every individual holds certain things to be true or false* good or
evil*

£0.

These are opinions (judgements of good* evil* true* false) and on
the basis of them all people make decisions that govern the course
of their action*

Jjl*

Every individual must make many decisions during the course of his
life* and the welfare of the individual* his family* and society ss
a whole depends on how well these decisions are made*

£6*

In terms of the scientific method the hypothesis (opinion) will be
tested* If this further information supports the original opinion*
more confidence can be placed in it* However* if it disagrees with
the opinion* all of the information must be re-examined in order to
formulate a new one* A new hypothesis is made to fit all of the
facts*

57*

A person using the scientific method is open-minded*

59*

Many people are faced with the necessity of making a decision with­
out adequate information to do it sceintlfically* They may lack
both time and facilities for gathering the needed iafomatloni but
the decision must be made nevertheless*

60*

In eases where a decision- must be made without adequate information
the scientifically trained person seeks the advice of some one whose
opinions are based on adequate information*
MEAN SCOBK 2*01 - 2*g0

2*

Primitive man developed forms of cooperation with other men which
resulted in the satisfaction of his basic requirements*

U* For an individual to succeed in obtaining his basic requirements he
must have certain skills that enable him to do some special task.
27*

The great scientist of the past were great because they could see
relationships not apparent to most man*

115

28.
30

.

Oar modern "greats" (in science) qualify In the same manner (as the
greats of the past)*
The hypothesis Is a statement of relationships that goes beyond
known facts*
AREA I H
Characteristics Common to A H Living Things

The Specific Objectives
1* To learn the characteristics of living things*
2* To understand the fundamental organisation of plants and
animals*
3* To understand the basic significance of respiration to living
things*
Principles
1* Protoplasm is a consequence of the organisation of matter and
energy*
2* The bodies of plants and animals are composed of cells and
products of cells*
3* Life processes are the activities of protoplasm*
U* Living things have a common structural pattern*
Cellular respiration is a process of releasing energy from
organic foods*
The Assignment
Biological Sceinee Lecture Syllabus, pp. 5-14*
Principle I - Protoplasm is a consequence of the organisation of matter
and energy*
MEAN SCQBK .5 - 1 *5 0
2*

Living things take Into their bodies non-living materials that are
synthesised chemically Into living protoplasm or oxidised to release
energy that is used in the living process*
MEAN SCORE 1*SL - 2*00

1*

Living things assimilate and utilise materials and energy*

116

3*

Idf* oan be maintained only when a constant stream of materials and
energy Is passing through the living organism*

U*

I1*1 of the substances In protoplasm are combined Into a complex
organisation in which chemical and physical processes occur that
result In life*

Principle II - The bodies of plants and animals are composed of cells or
products of cells*

MMUF SCORE *5 - 1*50
2*

Protoplasm usually takes the form of small blocks or spheres called
cells*

3*

In the smallest organisms the entire structure Is coaposed of one
cell* uhlle In the larger more complex living things such as man
the cells are multiplied millions of times to farm the complete
individual*
ME1H 8C0BB 1*51 - 2*00

1*

Each Individual organism is made of the same material* which Is a
complex kind of fluid substance known as protoplasm*

U*

Complex organisms are made of maqy millions of cells which are dif­
ferentiated into various kinds* In complex organisms the cells are
grouped on the basis of structure and function Into tissues and these
are combined to form organs* The .organs are united into systems#
Qroups of cells of similar structure which perform specialised
functions are called tissues*
IBdM SCOBS 2*01 - 2.$0

6*

The bodies of man and other complex animals as well as the bodies of
vascular plants are composed of several kinds of tissues*
MBAK SC OCT 2*51 - 3*50

7*

Organs In both plants and animals are ecsqposed of tissues, that work
together to perform a specific function in maintaining life*

117

8

.

Organs that work together to accomplish one of the primary functions
of the individual compose the organ systems.

Principle H I - Life processes are the activities of protoplasm*
MEIN SCORE *g - 1*50
2*

Every process or function of a living organism, such as digestion,
movement,'seeing or thinking is the result of the action of cells*

U*

of the substances In protoplasm are combined into a complex
organisation in which chemical and physical processes oeeur that
result in life*

6*

Living things grow*
MEIN SCORE 1*51 - 2*00

1*

Each individual is made of protoplasm organised into cells*

5>.

Living things assimilate and utilise materials and energy*

7*

Living things reproduce.

8.

Living things are adapted to their environment*

9.

Living things move*
IflaO l SCOHB 2 *0 1 -

3.

2 .5 0

The protoplasm of which cells are made is from 60 to 90 per cent
water. The rest is composed of proteins, carbohydrates, fats,
minerals and eraymes in varying proportions.

Principle XV - Living things have a common structural pattern*
MEIN SCORE *5 - 1*50
2.

Each individual is made of the same material, which is a ooaplex
kind of fluid substance known as protoplasm*

118

3 . In living organisms protoplasm usually takes the form of small blocks
or spheres called cells*
U*

The cell Is the unit of structure and function of all living things*

6* JL cell is mads of protoplasm and has tso major parts, the nucleus
and the cytoplans*

12* A thin, tough protoplasmic membrane, the cell membrane, surrounds
the entire oell*
M A W SCOBE lȣl - 2*00
5*

Every process or function of a living organism, such as digestion,
movement, seeing or thinking is the result of the action of cells*

15*

Groups of cells of similar structure which perform specialised
function are called tissues*

16*

The bodies of man and other complex animals as mall as the bodies of
vascular plants, are composed of several kinds of tissues*

1|2* Msrlstem tissue consists of small, thim-malled cells which' have the
ability to divide repeatedly*

66. Organs in both plants and animals are composed of tissues that work
together to perform a specific function in maintaining life*

69*

Each system is composed of organs that work together to accomplish
one of the primary functions of the individual*
M 6AW SCORE 2*01 - 2*S0

1*

Superficially no common pattern Is apparent, but the cmeson pattern
Is there*

11*

The remainder of the cell surrounding the nucleus is the cytoplasm*

35. Serve tissue is made up of nerve cells (neurons)*
39 • Blood is a fluid tissue and consists of a liquid plasma and floating
cellular elements*
4

- ,

1*3 . Moristem tissue Is found at the tips of stems and roots and in
vascular bundles where growth takes place.

119

Uu

The cells or meristem tissue differentiate or change Into all of the
other tissues of the plant body*

U5*

Epidermal tissue of plants is similar to epithelial tissue of animals
la that it covers surfaces*

70*

Tbs sqtstests of the higher animal Include the digestive, respiratory,
circulatory, excretory, skeletal, muscular, nervous, endocrine and
the reproductive system*
MEIN SCORE 2*51 - 3*50

7*

The nucleus is usually a sperical structure and located near the
center of the cell and limited by a thin, protoplasmic membrane
known as the nuclear membrane*

9*

Nucleoplasm is a thin, watery liquid in which is immersed a loose
irregular network of chromatin granules*

13*

Between the oeGH membrane and the nuclear membrane is the watery
qytoplasm which contains a variety of structures such as vacuoles,
food granules, cell products and wastes*

llu

Plant cells hare a wall made of cellulose outside of the cell
membrane*

17*

Epithelial tissue is thin and sfaset-llke and serves to cover surfaces
and to line cavities*

18*

The outer layer of the skin which covers the body le an epitlwllms,
as are the linings of the digestive tract, the abdominal cavity, and
the chest cavity*

19*

Every cavity, duet and vessel In the body le lined with epithelial
tissue*

20*

Connective and supporting tissue holds the parts of the body to­
gether and gives support*

21*

Several types of tissue are considered as connective and supporting
tissue* Tbay are white fiberous tissue, elastic tissue, fatty or
adipose tissue, cartilage and bone*

22*

The connecting and supporting tissues are characterised by the pres­
ence of cells plus a non-cellular substance known as matrix that
lies outside the cells*

120

23*
2km

Mosel* tissue contracts and in so doing Moves body parts*
Thar* arc three kinds of nosele:

striated or skeletal Muscle, snooth

or visceral Muscle, and heart or cardiac nusole*
2$m

Striated Muscle Makes up the mama of the body and noves the skeletal

parts*
26*

Striated nosele is composed of elongated cells with Many nuclei
and with alternating light and dark bands across the cells*

28*

Snooth nosele is so called because it lacks the striations of skeletal
ansde*

29m

Snooth nosele cells are spindle-shaped and contain but one nucleus*

30*

In jsaooth nosele the spindle-shaped cells lie parallel and font
sheets of tissue that fens the walls of various tubes and ducts of
the body*

31*

The intestine contains two layers of snooth nosele which contract
and nore the food along*

32*

Cardiac nosele is found in the heart*

33*

Cardiac xusole is nade of branching, striated cells*

3li* The cardiac Muscle cells contract and relax rhythnleally to produce
the pwdiring action that is so essential to the function of the heart*
36m

Neurons hare a rounded or triangular cell body to which are attached
fibers, the dendrites and axons*

37*

The dendrites and axons iaterconneot parts of the body and conduct
nerve lnpdses*

38*

Bundles of nerve fibers neks up the nerves*

UOm

She cells of blood Include the red cells and the white cells*

ill*

BLood tissue trensperts Materials throughout the body and aids in
disease resistance*

>

ii6* Spidermal tissue cells are usually snail and arranged in- a single
leyor*
klm

In leaf epidemic the outer cell walls are thick and covered with a
waxy layer uhieh reduces water evaporation, while In root epidemic
they are thin-walled sad perait the absorption of water*

121

i*8. Seme epidermal cells of roots hare slender projections that extend
between tbs soil particles* These ere the root hairs*
U9*

Parenchyma tissue is made of large, thin-walled, unspecialised cells*

50*

Some parenchyma cells are colorless and used mainly for storage,
while others, in leaves and near the surface of green stems, contain
chloroplast and are used mainly for food manufacture*

51*

IWo

52*

Fibers are extremely thick walled, elongated cells with pointed ends*
When mature they contain no protoplasm*

£6*

The bulk of plant stems is composed of wood tissue which contributes
the major support to the stem*

£7*

The transport of materials from place to place in a plant is accom­
plished by the vascular tissue*

of supporting tissue in plants are fibers and wood*

£6* Vascular tissue consists of tubes located in the phloem and duets in
the xylem*
£9*

The phloem tubes are made of tubular cells that contain protoplasm
and are stacked end on end, forming a column that extends from roots
to leaves*

60.

At the end of each of the cells of the phloem, the wall Isperforated,
permitting the protoplasm of one cell to oone in direct contact with
that of the cell next in line*

61*

Food is traneported through the tubes of the phloem*

62* Ducts are found in the xylem of roots, stems, and leaves*
«

$3*

The cells that foxm the ducts are tubular and placed end to end* As
they mature, the end walls dissolve, the protoplasm disappears and
the call walls form a continuous, hollow pipe-line through the plant*

6lu

Water and inorganic salts are transported by the dusts*

6$m

The ducts also aid in supporting the plants*

67*

Plants have fewer organs (than animals), the entire list being roots,
stems, flowers, and fruit with seeds*

66* Organs are ooaposod of many tissues, among which one is of prlmaxy
Importance while the rest are accessory but contribute to the function
of the primaiy tissue*

122

MEAM SCORE 3 « & - H»$0
Items number 8, 10, 27, 53# 5U, 55.
Appendix H .

Content nay be obtained from

Principle V - Cellular respiration is a process of releasing energy from
organic foods.
Syllabus assignment contained no Material related to principle number fire*
ABBA 17

Transformation of Solar Energy:

Photosynthesis

The Speeiflo Objectives
1.
To gain some understanding of the nature of matter and energy*
2* To study the energy relationships in living organisms.
3. To understand photosynthesis and to realise the significance
of this process to all living things.
U. To study the physical bases for the movement of water and dis­
solved materials la plants.
Principles
Matter is the substance of the universe.
The ultimate source of energy available to living organisms
within our planetary system is the radiation from the sum.
3. Life is a result of the organisation of matter and energy 1m
a dynamic equilibrium that earn be maintained only by the m e *
stent mtillaetlen ef natter and energy.
it. Energy and matter are neither created mar destroyed in life
processes.
5. In photosynthesis radiant energy is transformed to ohanloal
energy.
6 Only green plants, those containing chlorophyll, cam utilise
solar energy for the manufacture of foods.
7. Diffusion is the basic nooTienl an of transport operating In the
physical activities of organisms assisted by the movement of
fluids.
8. The synthesis of fats and proteins and carbohydrates other than
glucose is a sequel to photosynthesis which makes natter and
energy available to living things.
1.
2.

.

The Aeal gnrnout
Biological Solmnee Leotore gyllabus, pp. 15-17, pp. 21:31.

123

Principle I - Matter is the substance of the universe.
MEAM SCORE #5 * 1.S0
1.
2.

Matter occupies space* has inertia* and attracts other natter with
a force called gravity* It can be seen* felt* tested and swelled.
Matter is composed of atone.

lu

1'here arethousands of different hinds of natter* bat this does not
neam that there are thousands of different kinds of atens* for atone
can ooabine and form substanoes that have charaeteristlos entirely
different froai those of the atoau conposing then*

6.

The conbinations of these elsnents (atone) produce all of the kinds
of natter that nake up the universes

7.

This natter (of the universe) is usually in the form of noleoules*
whieh is the nans given to the particle fonaed by the union of tee
or nore atons.
MEAM S0C3BK 1*51 - 2.00

5.

There are ?2 kinds of atons in nature and sosm unstable atons pro­
duced in the laboratory* each of which is called a chenieal elenent*

8.

Erasp1.es of atons or elsnents are carbon* hydrogen* esygen and
nitrogen.

9m

Emaploa of noleoules are water* earbon dioxide* sugar* lard and
gelatins

10.

A noleeule of water is fenced whan two atone of hydrogen oonhlne
with one aten of oxygen. This reaction does not occur quite as
alngply as this* but for illustration eon be writtens
21

11.

+

o

—»

MjO

If one aton of carbon unites with two atone of oxygen the result is
a noleeule of carbon dioxide. C ♦ Og — » 00g

12. Molecules can also be oanblned to fern larger noleoules. For ezasple*
6 molecules of earbon dioxide (OOg) can be united with 6 molecules of
water (IgO) to form a noleeule of glucose
& this re­
action there are 6 nore noleoules of ojgrgew (0gj than are required in
the glucose noleeule, so they are given off as molecular oxygen, the

123

Principle I - Matter is the substance of tbe universe.
MEAM SCOBS *5 - 1*50
1. Matter occupies space, has inertia, and attracts other natter with
a force called gravity* It can be seen, felt, tented and snelled*
2*
U*

Matter is conposed of atons*
A'here arethousands of different kinds of natter, but this does not
naan that there are thousands of different kinds of atons, for atons
oan coablne and for* substances that hare charaeteristies entirely
different fron those of the atons composing then*

6* The combinations of these elonents (atons) produce all of the kinds
of natter that nake up the universe*
7*

This natter (of the universe) is usually in the for* of noleoules,
which is the nane given to the particle formed by the union of two
or nore atons*
MEAM SCORE 1*51 - 2*00

5*

There are 92 kinds of atoms in nature and sons unstable atons pro­
duced in the laboratory, each of which is called a chenical element*

8* Examples of atons or elements are earbon, hydrogen, oxygen and
nitrogen*

9* Examples of molecules are water, oarbon dioxide, sugar, lard and
galatin*
10* A noleeule of water is formed when two atoms of hydrogen eosfelae
with one atom of oagrgen* This reaction does not occur quite as
simply as this, but for illustration can be writteat
2H + 0 — >
HjO
11*

If one atom of carbon unites with two atons of oagrgsn the result is
a noleeule of carbon dioxide* C
Og — ► 00^

12* Molecules earn also be combined to fens larger molecules* For example,
6 moleeules of oarbon dioxide (CO2) can be united with 6 noleoules of
water (H9O) to form a noleeule of glucose (CtfjigOg)* In this re­
action there are 6 more molecules of ojqrgon ((>2? Than are required in
the glucose noleeule, so they are given off as moleeular oxygen* The

equation as written in chemical shorthand is:
'
_
^ cfiPl2°6 + %
earbon dioxide water
glucose
oxygen
MEAN SCORE 2#01 - 2#$0
13*

Fat, another kind of food, is also formed by the combination of
oarbon, hydrogen and oxygon#

lit# Protein, another food, is formed by the combination of carbon#
hydrogen, ooygen, nitrogen, end frequently other elements such as
sulfur, phosphorus and occasionally magnesium and Iren#
15#

Vitamins also contain earbon, hydrogen, and oaqrgen#
MEAM SCOBB 3*51 - lu50

Item number 3#

Content nay be obtained from Appendix II#

Principle II - The ultimate source of energy available to living organ­
isms within our planetary system is the radiation from
the sun#
MEAM SCOHB #5 - 1.S0

1#

Stored chemical energy is the source of all energy used by living
things#

2# Oreom plants have the ability to take the light energy of the a m
and convert it into chemical energy#
3#

U#

She energy that is used by living things to carry on the process of
life is ohemioal energy stored in molecules of carbohydrates, fats
and proteins# The ultimate source of this stored energy is sunlight,
which is changed from light energy to stored or potential chemical
energy*
Only groom plants eon store energy (from the sun) in this fashion,
so the source of all energy used by living things is the green plant#

MEAN SCORE 2>0CL - 2.50
6*

The light wares which produce the red, blue, and riolet regions of
tha spectrum are abosrbed by the chlorophyll in the palisade and
spongy cells, and the energy is used in combination with water and
carbon dioxide to produce glucose*
MEAN SCORE 2.51 - 3«g0

5*

Sunlight consists of light wares of different lengths which can be
separated by passing through a prisn to form a ninature rainbow
consisting of the following colors: red, orange, yellcw, green,
blue, indigo and riolet*

Principle III - Life is a result of the organization of natter and energy
in a dynamic equilibrium that can be maintained only by
the constant utilization of natter and energy*
MEAN SCORE *5 - !»#>
1*

Within the organise, natter and energy become a part of a complex,
integrated mechanise that liras*

2*

Tha organisation of the natter and energy is stable so long as life
continues, but it is a d y n a m i c sort of organisation in which both
natter and energy are continually being utilised*

3*

Life ceases if non-lirlng naterlals and energy are not constantly
being fed into the liring protoplasm*

U*

9 m stored ohwnlnal energy In organic foods is the source of all
energy used by liring things*

6* Oxygen is necessary for this process (of releasing energy from stored
food) which explains why liring organisms need a constant supply (of
oxygen)* The equation for this energy releasing reaction is:
C^l2°6 4 &>2 ---> Energy + 6CO2 4 ^
MEAN SCORE 1*$1 - 2*00

*>•

To use (this) stored energy, liring things break the bonds that hold
the atons of the noleeule together and the energy is released*

126

Principle 17 - Energy and natter are neither created nor destroyed In
life processes*
MEAN SCORE *g - 1*50
•>*

Ehergy appears in sereral forms and can be changed from one foxm to
another*
MEAN SCORE 1*51 - 2,00

1*

In order to maintain life* non-living matter mast be taken from the
environment and built into the structure of the body*

2*

Ehergy must also be taken from the environment and used to carry on
the living functions*

3*

Within the organism matter and energy become a part of a complex*
integrated mechanism that lives*

6*

In all (of these) forms of energy one type of motion replaces another*

8*

Energy can be stored*
MEAN SCORE 2*01 - 2,$Q

U*

The organisation of the matter and energy is stable so long as life
continues* but is a dynamic sort of organisation in which both
matter and e n e r g y are continually being utilised*

9*

Stored energy is called potential energy*

10*

Stored chemical energy is the source of * n
things*

energy used by liviz^

MEAM SCORE 2*51 - 3*90
7*

The energy of motion is called kinetic energy*

Principle V - In photosynthesis radiant energy is transformed to chemical
energy*

127

MEAM SCOHB

- 1*50

1,

Photosynthesis is the process whereby water, carbon dioxide, and
light energy are conblned through the aid of chlorophyll to produce
carbohydrate food*

2,

Chlorophyll In a liring cell le essential In this reaction (photo­
synthesis) because it alone can sake use of the radiant energy of
the sun to separate certain of the carbon atons fron the oxygen in
the carbon dioxide molecule; to separate certain of the hydrogen
atons fron water noleeule, and to recombine these atoms to form
glucose, a simple sugar.
MEAM SCQBE 1,51 - 2,00

3,

The chlorophyll probably acts as a catalyst In this reaction (photo­
synthesis), but the details of the prdcess are still obscure,

lu

(In the photosynthesis reaction) six molecules of carbon dioxide
combine with six molecules of water to produce one molecule of
glucose. The equation written in chemical shorthand 1st
6C02 + 6H 2O + (energy) — > c^ i 2°6 * ^°2
MEAN SCORE 2,01 - 2,50

5,

Six molecules of oxygen are not utilised in the process (of photo­
synthesis) and diffuse to the atmosphere. This is the primary source
of oxygen for cellular respiration in animals and plants,

6,

Photosynthesis s o r e s not only as the source of
food
for all llTing things but also supplies the oxygen which is neces­
sary to release the energy so that it can be used by liring organisms,

7,

The glucose formed within the plant cell (by photosynthesis) may be
oxidised (combined with free oxygen), and the chemical energy which
is released is used by the plant,

8,

The energy used by plants cannot be taken directly from the sunlight
but mnst be released by oxidation from a food molecule Just as in
animals.

Principle VI - Only green plants, those containing chlorophyll, can utilise
solar energy for the manufacture of foods.

128

MEAM SCORE *5 - 1.50
1*

Green plants have tha ability to taka tha light energy of the sun
and convert it into chemical energy*

2*

They (green plants) use carbon dioxide and water and combine then
into molecules of glucose*

3*

Within the glucose noleeule is the energy which has been converted
from light energy into chemical energy* The aquation for this pro­
cess is: 6C0j> + 6Hj>0 4 Energy -- » C6H1206 * ^ 2

U*

The ultimate source of stored energy (in food) is sunlight which is
changed from light energy to stored or potential chemical energy*
Only green plants can store energy in this fashion* so the source
of all energy used by living things is the green plant*

5*

The green plant is the source of all energy-yielding foods and also
of most of the foods that do not contain energy* Water and some
minerals may be obtained from nonplant sources*

29*

The leaves are the food-making organs of the plant*
MEAM SCORE 1*51 - 2*00

38*

On both upper and lower surfaces of most leaves are tiny openings*
tha stomates*
MEAM SCORE 2*01 - 2*ff)

35*

The cells of both layers (palisade and spongy layers) contain
chloroplast*

39*

These (the stomates) permit air from the atmosphere to enter the air
spaces of the leaf*

1*2*

Veins extending throughout the leaf* are extensions of the vascular
bundles of the roots* stems* branches and leaf stems*
MEAM SCOEB 2*51 - 3*56

6*

The more common flowering plants are composed of roots* stems*
leaves* flowers and fruits*

129

7*

The roots extend into the ground where they serve to anchor the
plant and to absorb and conduct water and Inorganic Minerals*

13*

In the center of the root is the vascular tissue*

19*

The s t e m also conduct water, minerals and other foods*

22*

Inside of the cortex (of the stem) is the central cylinder of vascu­
lar tissue*

30*

Hie leaf is usually of two parts, the leaf stem and the blade*

31*

The leaf stem supports the blade and contains conducting tissue*

3lu

Inside the leaf are two cell layers, the palisade layer and the
spongy layer*

36*

The palisade layer is made of Irregular and somewhat elongated cells
that stand more or less close together*

37*

The spongy cells are nore or less irregular in shape and have air
spaces between them which are interconnected throughout the leaf*

iiO*

The stomates are usually more numerous on the under surface of the
leaf than on the upper surface*

Ul*

Each stomate is surrounded by guard cells which regulate the sise of
the opening*
MEAM SCORE 3*51 - h*50

Items number 8, 9, 10, U , 12, 1U, 15, 16, 17, 18, 20, 21, 23, 2h, 25*
26, 27, 28, 32, 33* Content may be obtained from Appendix II*
Principle Y U - Diffusion is the basic mechanism of transport operating
In the physical activities of organisms assisted by the
movement of fluids*
MEAN SCORE *5 - 1*50
1*

Plants absorb water from the soil by means of the root hairs*

3*

lhe water enters the cells of the root by a form of diffusion known
as osmosis*

130

lu

Diffusion Is a process whereby one substance becomes spread through­
out another substance*

6*

The force which causes the sugar to spread Is a molecular force*

21*

Osmosis plays an important part in the absorption and transport of
water by a plant*

29*

When transpiration occurs from the surface of the palisade and spongy
cells* the water within these cells diffuses to the surface and re­
places that lost by evaporation* with the result that the concentra­
tion of water within the cell is decreased below that in adjacent
cells not exposed to the air* Osmosis results and the water mores
fron these adjacent cells into the cells lining the air spaces* This
reduces the water content of these cells* which In turn causes water
to move by osmosis from the cells next In line* This is repeated
from call to cell starting with the ceils lining the air spaces and
ending with the cells surrounding the xylem of the veins*

33*

Minerals that are in solution in the soil water move by diffusion
into the epidermal cells of the roots and then Into the aqrlen*

36*

Plants receive carbon dioxide from the air* which diffuses into the
leaves through the stomates and than into the palisade and spongy
cells*
MEIN SCORE l*gl - 2.00

2*

The roots and attached root hairs lie between soil particles which
are Immersed in water*

5*

An example of diffusion is sugar and water* Wham sugar is added to
water the sugar becomes dissolved and in so doing It gradually spreads
throughout the water until it is equally distributed*

7*

Molecules are subject to two opposing forces* Attraction tends to
hold them together and their motion causes them to separate*

11*

(When the molecules separate) such molecule moves in a straight line
away from its neighboring molecules until it is stopped* by collision
either with another sugar molecule* with the wall of the container*
with the surface of the liquid* or with the water molecules*

13*

Because the molecules move in a straight line until stopped and than
immediately start off in another straight line* it is obvious that
the noleoules will tend to move away from the area of greater con­
centration to one of lesser concentration* Repeated collisions in
congested areas prevent any great movement toward this area but in
sparsely occupied areas progress is not impeded*

131

lU*

Finally the molecules fill all of the available space and become
equally distributed among the water molecules*

15*

Osmosis is diffusion of water through a membrane so constructed that
It permits molecules of water to pass through but does not permit
molecules of a dissolved substance to pass through* Such a membrane
is differentially permeable*

16*

If a vessel Is so constructed that a differentially permeable membrane
separates a solution of pure water and a solution of sugar and water,
the water molecules can move both ways through the membrane but the
sugar molecules cannot because the membrane permits the water mole­
cules to move through but prevents the sugar molecules from doing the
same*

17*

The movement of the water molecules is entirely independent of the
sugar molecules and they move In accordance with the laws of dif­
fusion: that Is, they move from an area of greater concentration
of water to one of lesser concentration of water*

18*

(In an osmotic system) the water molecules are more concentrated for
any given space within the pure water side than they are on the sugar
side at the membrane* This Is due to the presence of sugar molecules
which by occupying space among the water molecules cause them to be
farther apart than they would be in a pure solution*

19*

Hence, the water moves by diffusion from the pure water side to the
sugar solution side of the meabrane*

20*

She sugar molecules would move by diffusion through the membrane te
the pure water aide likewise, but they are prevented from doing se
by the membrane*

22*

The roots (of plants) with their root hairs lie between particles of
soil immersed in water*

23*

The protoplasm within the epidermal cells. Including the root hairs,
contains more substances In solution, such as sugars and organic
acids, than the water in the soil (In which the root hairs are
Immersed)*

2U*

The cell membrane (of the root hair cells) acts as a differentially
permeable meabrane which permits the flow of water through it, but
does not permit the dissolved substances of the cell to flow out*
Ihe result is that the water diffuses into the cell by osmosis
through the cell mmabrane*

25*

The water (that passes through the root hair cell membrane) moves
first into the root hair cells and other epidermal cells that sur­
round the root* This Increases the water concentration of these

132

cells over that of the cells next to them Inside of the root* Osmo­
sis again occurs and water moves through the epidermal cells into
these adjacent cells*
26*

A repitition of this process of osmosis from cell to cell toward the
center of the root brings the water eventually to the xylem cells of
the vascular bundle in the center of the root*

30*

The cells surrounding the xylem of the vein (of the leaf) receive
water from the xylem*

35*

In the leaves minerals in solution move from the veins into the
palisade and spongy cells by diffusion*
MEAM SCORE 2,01 - 2*50

8*

This separating force (acting on molecules) is heat energy*

9*

When sugar (for example) is dry, the attractive or cohesive force of
the molecules on each other is greater than the dispersing force and
they cling together In crystals of sugar*

10*

When the crystals (of sugar) are moistened with water, the bends
that hold the molecules together are loosened and they separate*

12*

Whenever collision occurs the molecule moves in another direction,
in a straight line again, until it bumps into something else*

27*

The water is conducted upward by capillarity, root pressure, and
other forces through the xylem of the root to the xylem of the stem,
through the agrlem of the stem, branches, and leaf stems until it
eventually reaches the leaves*

28*

The water evaporates from the surface of the spongy and palisade
cells of the leaf* This evaporation is known as transpiration*

31*

The xylem of the veins (of the leaf) is connected directly with that
of the leaf-stern which is connected with the xylem of the stem* The
stem xylem is connected with the root xylem*

32*

Movement of the water upward through the xylem ducts is due in part
to capillarity, root pressure, and other forces not fully understood*

3U*

Minerals are conducted upward into the leaves by the xylem of the
roots, stems, leaf-stems, and veins*

133

Principle VIII - The synthesis of fata and proteins and carbohydrates
other than glucose Is a sequel to photosynthesis which
makes natter and energy available to living things*
MEAJf SCORE *5 - 1*50
3*

U*
5*

The glucose nay also be changed directly into double sugar or starch
and stored In the leaves or it nay be transported in the phloen te
sons other part of the plant and there stored as sugar or starch*
(The glucose) nay also be changed into fat, which nay be stored*
Finally other chemicalelements nay be added and the glucose changed
Into protein, which is used to build more protoplasn for the plant
cells or stored*
MEAN SCORE 1*51 - 2*00

1*

The glucose foraed within the plant cell (by photosynthesis) nay be
oxidised (combined with free ooqrgen), and the chaaH cal energy which
is released is used fay the plant*

2*

The energy used by plants cannot be taken directly from the sunlight
but must be released by oxidation frcsi a food molecule just as in
animals*
MEAM SCORE 2*01 - 2.$0

6*

In normal growth and development of plants food is stored In roots,
stmas, leaves and fruits*
AREA V
Utilisation of Matter and Energy:

Unit 1, Foods and Digestion

The Specific Objectives
1* Tb classify energy-containing foods as to their general char­
acteristics and their specific actions*
2* Te realise the significance of vitamins and the Importance of
water and mineral salts In the diet*
3* To understand the basic significance of the digestive processes*

13U

Principle*
1, Food is the only form in which matter can be utilised by living
things*
2* The chemical energy of organic food is the only form in which
energy is utillsable by the metabolic activities of organisms*
3. Solubility and diffusibility are prerequisites for the absorp­
tion of foods*
it* Digestion results in organic foods' being changed into their
soluble and diffusible components*
5* Water is a basic medium for life processes*
The Assignment
Biological Science Lecture Syllabus, pp* 18-21, 31-33*
Principle I - Food is the only form in which matter can be utilised by
living things*
m u r score * 5 - 1 * 5 0
1*

Food is any material that can be used by living things to maintain
the normal state of protoplasm*

2*

Some foods furnish energy and some foods provide building materials,
while others aid in different ways in the metabolism of the body*

3* Foods include the organic foods- carbohydrates, fats, proteins and
vitamins- and the inorganic foods- minerals, water, oxygen and carbon
dioxide*
5*

The carbohydrates supply living things with their main source of
energy*

18*

Fats are another good source of energy for living organisms*

25.

Proteins are used as building materials for the protoplasm of the
body but may also be used as a source of energy*

29*

The molecules (of proteins) are f onaed by the union of simpler
mdeoules called amino acids*

39*

Vitamins are organic compounds required of living organisms in vary
minute amounts, but whose absence causes nutritive deficiency diseases*

69*

Water and minerals are the essential inorganic minerals*

135

MEAN SCORE 1*51 - 2*00
It* Co— on foods such as meat* fruits and vegetables are Mixtures of
the basic food substances*
6*

Carbohydrates include sugars* starches* glycogens and celluloses*

19*

Fats are contained in quantities in such foods as vegetable oils*
nuts* butter* crean* lard* bacon and other fatty neats*

20*

The elements carbon* hydrogen and oxygen nake up the fat molecule*
but the hydrogen and oxygen are not in the ratio of HgO as In
carbohydrates*

22*

Because fats are less oxidised than carbohydrates* they contain — re
energy per unit of weight*

2li*

Fats are for— d by the union of fatty acids and glycerol* which are
relatively simple Molecules that hare the bullri1ng-block relationship
to complex fat molecules that the simple sugar molecules* such as
glucose or fructose have to the coaqplex carbohydrates*

26*

Foods high in protein content are lean — ate* eggs* gelatin* cheese
and nuts*

27*

Proteins contain the chemical element nitrogen as well as carbon*
hydrogen and oaqrgan*

30*

The anlno acids have the same relationship to protein molecules that
the simple sugars hare to complex carbohydrates and that fatty acids
and glycerol hare to fats*

31*

Anlno acids combine in infinite ways to form the large and complex
protein molecules that make up the major proportion of living pro­
toplasm*

35*

The aaino acids combine in different proportions to form many dif­
ferent kinds of proteins found in living things*

U2*

With the exception of vitamin D* the primary source of vitamins in
nature is plants*

U5*

Vitamin A is essential for normal growth* for the maintenance of
healthy epithelial tissues* and for the prevention of night
ness*

1*9*

Vitamin B is necessary for normal metabolism* for the prevention of
pellagra and to maintain healthy nerves*

136

66*

Vitamin K la essential for the nonaal clotting of blood*

70*

Life as we know It would be Impossible without water*

71*

The minerals necessary for organisms include calcium, magnesium,
potassium, and sodium in combination with chloride, phosphate and
carbonate*

72*

Small amounts of iron, copper, cobalt, iodine, fluorine, manganese,
and sine are also necessary (in the diet)*
MEAM SCORE 2,(XL - 2*50

7*

Chemically the carbohydrates are all fundamentally alike in that
they are all composed of the three elements - carbon, hydrogen and
oxygen*

8*

There are usually six (or multiples of six) atoms of carbon In the
carbohydrate molecule and the hydrogen and oxygen are usually pres­
ent in the same proportion as in water, that is, 2 parts of hydrogen
te 1 of oxygen (HpO)*

9*

The formula for glucose (C^ftoO^), which is a simple sugar, illustrates
this molecular relationship tin the carbohydrate molecule)*

10*

There are three classes of carbohydrates - simp le sugars, double
sugars, and complex carbohydrates*

16*

By combining many simple sugar molecules in the sums fashion complex
molecules of starch, glycogen or cellulose can be formed*

21*

In fats there is less oxygen in proportion to the hydrogen than In
the case of carbohydrates*

28*

Phosphorus and sulfur are often contained in the molecules (of pro­
tein)*

32*

Amino acids are recognised chemically by the grouping together of
nitrogen and hydrogen as NHj*

36*

In nan the proteins in the cells of different organs ▼axy one from
another*

U3m

Vitamin A is found in animal products such as egg yolk, butter, and
cod-liTer oil*

137

lib*

Certain pigmented plants such as carrots, squash, sweet potato and
yellow corn contain a yellow pigment, carotene, which can be trans­
formed by seme animals into vitamin A*

ii6*

Vitamin B is found in many plants, particularly in bran, wheat
embryo and yeast*

1*8•

Milk, oysters and lean pork are animal sources of vitamin B*

50*

Vitamin B causes root growth in plants*

51*

The effects of a deficiency of vitamin B on the nervous system vary
from mold nervous disorders to the more severe symptoms found la
beriberi*

53*

Vitamin C is present in fresh fruits, particularly citrus fruits*

51u

In the absence of vitamin C, scurvy develops*

*>£•

Scurvy is a degenerative disease affecting many parts, including the
teeth and bones*

57*

Vitamin D is abundant in the liver oils of various fish, particularly
cod and halibut*

58*

Irradiation of milk, yeast and certain plant and animal fats will
produce calciferol*

59m

Human beings can synthesise vitamin D if the akin is exposed te
direct sunlight*

60*

Vitamin D is necessary for the absorption of calcium and phosphate
from the intestine*

61*

The absence of vitamin D results in a bone disease known as rickets*

65*

The normal diet contains ample quantities of vitamin B*

67*

Vitamin K is used to reduce bleeding in modern surgery*

68*

Vitamin K is foamed in the intestine by the action of bacteria on
food residues and consequently is not needed as part of the diet*

mat SCOHE 2*51 - 3*50
11*

Glucose, fructose and galactose are simple sugars and hare the
formula

138

12*

Maltose, lactose and sucrose or cane sugar are double sugars and
hare the formula C12H22°il*

13*

Starch, glycogen and cellulose are complex carbohydrates and have
tbs formula (C^E^Dc;) •

liu

Two molecules of a simple sugar can combine to form one molecule of
a double sugar* In this process one molecule of water Is released*

15*

When two molecules of a simple sugar combine to form one molecule of
a double sugar the reaction can be written in chemical shorthand as
follows:
C6hl2°6 + cA 2 ° 6
c12h22°11 + H2O
simple
simple
double
water
sugar
sugar
sugar

17*

The "n" in the formula for a complex carbohydrate (C^hioO^n repre­
sents a high number (from 20 to 300) of simple sugar molecules that
hare combined to font the complex carbohydrate*

23*

Fats are characterised also by being soluble in alcohol and ether
and they feel greasy to the touch*

33*

NHg is known as the amino group*

3l»*

There are about twenty-three amime acids knows*

37*

There are also certain differences apparent in proteins of different
Individuals*

38*

The proteins found la different species of animals and plants differ
greatly*

¥>*

the vitamins wars first named alphabetically A, B# C, D, X and K,
but these n a m e are gradually being replaced by the chemical name
of the substance as these become known*

ill*

Several of the vitamins have been synthesised in the laboratory and
manufactured for comerelsl sale*

U7*

Vitamin B is a complex of several chemical substances*

52*

Vitnaln C is also known as ascorbic acid*

56*

Vitamin D is known as calciferol*

62*

Vitamin X is known chemically as tocopherol*

63*

Vitamin X is probably essential for the maintenance of normal repro­
ductive aotivites*

139

6km

Vitamin E ia found in wheat germ oil and in germ oil of other grains*

Principle II - The chemical energy of organic food la the only form in
which energy ia utiliaable by the metabolic activities of
organisms*
MBAM SCOHB *g - l,gO
1*

Chemical energy can be stored In molecules*

2*

Green plants have the ability to take the light energy of the sun
and convert it Into chemical energy*

h*

Within the glucose molecule produced by the green plant is the
energy which has been converted from light energy into chemical
energy*

5*

Fats and proteins also contain stored energy*

6*

To use this stored energy (In organic foods) living things break
the bonds that hold the atoms of the molecule together and the
energy is released*

7*

Thus the energy that is used by living things to carry on the pro*
cess of life Is the chemical energy stored in molecules of carbo­
hydrates* fats and proteins*
MEAN SCORE 1*51 - 2*00

3*

Green plants use carbon dioxide and water and combine them into
molecules of glucose*

Principle I U - Solubility and diffusibility are prerequisites for the
absorption of foods*
MEAN SC0BB *S - 1*50
1*

Food is stored in the form of large, complex* Insoluble molecules
in both plants and animals and c a m o t be used until the molecules
are made simpler and soluble in water*

2*

Neither plants nor animals can transport food material through the
body except in a soluble form*

lUo

3.

Food cannot be used for energy nor for building protoplasm unless It
is in a simple molecular form*

lu

Splitting complex molecules into simple ones, which makes them sol­
uble in water, is called digestion*

Principle IF - Digestion results in organic foods being changed into
thsir soluble and diffusible components*

MEAN SCORE *5 - 1*50
1*

Splitting ocaqplex molecules into simple ones, which makes them sol­
uble in water is called digestion*

3*

The process of digestion is facilitated by the action of enaymes*

lu

Ensymes are organic catalyst produced by living cells which speed up
or slow down chemical reactions without themselves being used up*

5*

In the process of digestion ensymes speed up the chemical reactions*

7*

In digestion water is added chemically*
MEAN SCORE 1,£L - 2,00

2*

Digestion is essentially the same in both plants and animals*

6*

In the process of digestion ensymes enable the chemical reactions to
take place at relatively low temperatures*

10*

In plants digestion occurs through ensyme action wherever food is
stored*

12*

After digestion the food is soluble and can be transported, usually
through the phloem, to the part of the plant that needs the energy
or building material*

lU*

The process of digestion ia animals is fundamentally the same in all
forms*

22*

The ameba protoplasm surrounding the food vacuole secretes digestive
ensymes into the vacuole which digest the food and thus make it sol­
uble*

23.

In the ameba, digested food in the vacuole is then absarbed through
the vascuolar membrane into the protoplasm, where it is utilised for
energy production or to build more protoplasm*

2lu

The essential features of the processes associated with food getting
in the ameba are (1) food intalce (2) secretion of digestive enzymes
by the protoplasm through the membrane surrounding the vacuole f (3)
breakdown of complex food molecules by the ensymes into simpler sol­
uble molecules, (h) absorption of the soluble molecules through the
vacuolar membrane into the protoplasm of the cell*
MEAN SCORE 2*01 - 2.£0

8.

The chemical equation for the digestion of starch is:
(e6"is£5)a
starch

*

“V
-*•
water

"?6fy.Z°6
simple sugar

11.

Digestion in plants may occur in the roots, stems, leaves or seeds*

13.

The growing tips of roots or stems are the usual destination of such
soluble energy-containing foods*

15.

Before digestion can take place in an animal, it must eat either
plant material or another animal that has already fed on plants*

16.

The simplest illustration of the fundamentals of food intake and
digestion is found in a single celled animal, the ameba*

21.

The food vacuole of the ameba acts as a digestive structure*
MEAN SCORE 2*51 - 3.50

9*

There is no digestive system in plants*

17*

The ameba is microscopic in size, lives in water, is composed of one
cell only, and moves by a flowing of the protoplasm*

19*

When a food particle is met in the wanderings of the ameba, two or
more protoplasmic processes move toward and around the food until
it is completely surrounded* The processes also d o s e over the top
and bottom of the food until it is completely surrounded*

20*

The surrounding of the food particle by the protoplasm of the ameba
forms a space inside the cell which contains water and the food
particle. This space is known as the food vacuole*
MEAN SCORE 3.51 - U*50

Item number 16.

Content may be obtained from Appendix II*

Principle V - Water is a basic medium for life processes*
MEAN SCQBE *5 - 1*50
1*

The protoplasm of which cells are made is from 60 to 90 per cent
water*

2*

Pood is stored in. the form of large, complex* insoluble molecules
in both plants and animals, and cannot be used until the molecules
are made simpler and soluble in water*

6*

Water is part of the protoplasm and of all body fluids*

7*

Life as we know it would be impossible without water*
MEAN SCORE 1*51 - 2*00

3*

All forms (of life) require a certain amount of water, tut some re­
quire less than others*
MEAN SCQBE 2*01 - 2.$0

lu

Chemicals dissolved in water also have an effect on the kinds of
organisms living in any area*

$•

Water comprises over 60 per cent of the human body b y weight*
AREA T
Utilisation of Matter and Energy:

Unit 2, Organ Systems

The Specific Objectives
1* To understand the structural characteristics of the digestive,
respiratory and eaccretezy systems which function directly in
the lntake-outgo activities of living things*
2* To understand the significance of these organ systems to the
organism as a whole*

1U3

Principle®
1* The exchange of natter between organisms and the environment
is accomplished in the simpler organisms by the physical pro­
cess of diffusion almost exclusively* Ia the complex multicellular animals* supplementary specializations of tissues
and organs evolved to effect the intake-outgo activities*
2* The specializations in the digestive process which evolved to
meet the organism's requirements are those Involved in (1) the
mechanical subdivision of foods (2) the increased secretion of
digestive fluids (3) the stirring of the digestive tract con­
tents (U) the absorption of the end products of digestion and
(5) the reabsorption of water from the fecal wastes*
3* Respiratory organ systems evolved to effect adequate gaseeus
exchanges between the organism and the environment* All
respiratory organs are characterised by having sufficiently
large areas of thin* moist membranes richly supplied with
blood vessels to meet the oxygen intake and carbon dioxide
outgo demands of the organism* The air-breathing organisms
possess a system of tubes which permit a more ready diffusion
of gases to and from the respiratory surfaces*
U* Excretory organ systems evolved to maintain normality in the
chemical composition of the fluids comprising the internal
environment of the organism* In the multieellular animals
this is accomplished by a system of tubes and channels of
varying degrees of complexity which permit the outgo of meta­
bolic wastes filtered from the blood or other body fluids to
the external environment*
The Assignment
Biological Science Lecture Syllabus* PP* 33-U2, 55-63.
Principle I - The exchange of matter between organisms and the environ­
ment is accomplished in the simpler organisms by the
physical process of diffusion almost exclusively* lb the
oomplex multieellular animals* supplementary specialisa­
tions of tissues and organs evolved to effect the intakeoutgo activities*
HEIM SCORE *5 - 1*50
3*

Associated with
secrete enzymes and

thedigestive tube (in man) are several glands* which
other essential materials necessary for digestion*

6*

The fundamental method of obtaining oxygen and removing carbon diox­
ide is the same for both land and water animals* though the details
of the mechanism may differ*

lhli

7,

The fundamental method of obtaining oxygen and removing carbon diox­
ide in both land and aquatic animals is diffusion through a moist
cell membrane*

3*

*!*>• cell membrane must be moist or diffusion through it cannot occur*

MEAN SCOHE 1*51 - 2*00
1*

Man is a complex animal made of billions of cells* some of which
are specialised and combined to form a digestive qjrstem*

2*

The digestive system (in man) is a tube extending from mouth te anus
through which the food must pass to be digested*

lu

Practically eii animals must take in free ooQrgen and must get rid of
carbon dioxide*

•>*

The immediate source of oxygen and the place of disposal for carbon
dioocide is air for land animals and water for aquatic animals*

9*

The simplest example of the morrhanl am (of diffusion) is a single*
celled organism* such as the ameba*

12*

Cellular respiration in the ameba removes the free oxygen from the
cell with the result that the concentration of oxygen within the
cell is below that of oxygma in the water outside* Therefore* the
oxygon diffuses from the water through the moist cell membrane Into
the protoplasm of the cell*

13*

Cellular respiration in the ameba also produces carbon dioxide*
which accumulates within the cell in quantities greater than those
present in the water outside the cell membrane* Therefore* carbon
dioxide diffuses out of the cell through the moist cell membrane
into the surrounding water*
MEAN SCORE 2*01 * 2*gQ

10*

The cell membrane of the ameba is covered with water in which the
ameba normally lives* and this water contains oxygen dissolved in it*

U*

Oxygen is also present within the cell* where it is used in cellular
respiratien*

1U5

Principle U

- The specialisations in the digestive process which evolved
to aeet the organism's requirements are those involved in
(1) the nechanloal subdivision of foods (2) the increased
secretion of digestive fluids (3) the stirring of the
digestive tract contents (It) the absorption of the end pro­
ducts of digestion and (£) the reabsorption of water from
the fecal wastes*
MEAN SCOHE *5 - 1*50

1*

The (human) digestive system is a tube extending from mouth to anus
through which the food must pass to be digested*

2*

Associated with the tube are several glands, which secrete ensymes
and other essential materials necessary for digestion*

8*

Food in the mouth is partly digested by the action of an easyne
secreted by the salivary glands*

53*

The folds and villi serve to increase the surface area of the (in­
testinal) epithelium, and thus to increase the digestive and absorp­
tive capacity of the intestine*

62*

Bile emulsifies the fats, breaking them up into snail droplets*

63*

The enulsification process Increases the surface area of the fat
globules and thus aids the fat digesting ensymes in their work*

66*

The pancreas secretes three kinds of digestive ensymes into the
small intestine* They are protein-digesting, fat-digesting, and
carbohydrate-digesting ensymes*

67*

Glands in the walls of the intestine also secrete protein and
carbohydrate-digesting ensymes*

71*

The amine acids and simple sugars are abosrbed through the epithe­
lium of the small intestine, into small blood vessels, the
capillaries*

72*

Glycerol and fatty acids go not into the capillaries, but into the
branches of the lymphatic system located la the villi*

7ii*

The amount of absorption possible (from the small intestine) is
dependent on the surface area of the epithelium*

85*

However, a mere important function of the large intestine (than the
absorption of digested food) is the absorption of water*'

1U6

MEAN SCORE 1,51 - 2,00
3*

The (digestive) tube le diTided into the following partes mouth,
throat, esophagus, stomach, small intestine, large intestine,
rectum and anus*

lu

The major glands that secrete Into the tube are salivary glands,
gastric glands, liver, pancreas, and intestinal glands*

7*

Food is taken into the mouth, where it is broken up by the chewing
action of teeth, tongue and cheeks*
Chewing increases the area exposed to the action of ensymes and
speeds up digestion*

10*

The salivary glands also secrete mucin, which mixes with the food
to make the particles stick together in small balls and to slide
more easily down the throat*

23*

The pharynx is a common passage way for food and air*

25*

The esophagus is a tube that connects the pharynx with the stomach*

3U*

The stomach is am enlarged portion of the digestive tube*

35*

The stomach acts in part as a sac or reservoir for the temporary
storage of food*

36*

The inside of the stomach is lined with am epithelium and thousands
of glands*

37*

The glands of the stomach are of two kinds, those that secrete
digestive ensymes and those that secrete hydrochloric acid*

1»0*

The squeeslng action (of the stoauich) churns the food and breaks it
up even more than occurred in the mouth*

Ijl*

The squeeslng action of the stomach also forces the food into the
small intestine*

b2*

The ensymes secreted by the glands in the stomach wall act on pro­
teins only*

1*3*

The ensymes produced by the glands in the wall of the stomach act
only in am acid medium, hence the necessity of hydrochloric a d d in
the stoaach*

1Ui*

Practically no food is absorbed in the stomach*

11*7

U5*

After the food has remained In the stomach for three or four hours
end has been churned end ected upon by ensymes it is forced into the
— » n intestine by a peristaltic were of the stomach wall*

1*6.

The

51*

Digestive glands lie in the wall (of the small intestine) beneath
the epithelium and secrete into the cavity of the tube*

52.

The inside walls (of the small intestine) are folded and on these
folds finger-like villi project into the intestinal cavity*

55.

The intestinal walls contain many blood vessels and nerves*

57*

The food and digestive juices are thoroughly mixed and churned in
the small intestine by peristalsis and the pumping action of the
villi*

58*

After a period of churning (in the seal 1 intestine) the food is
pushed along toward the large intestine*

59*

The liver is a large gland that lies in the anterior portion of the
abdominal cavity*

60*

One of the liver's many functions Is to secrete
intestine by way of the bile duet*

61*

The bile mixes with the food as it enters theintestine
the stomach*

68*

Digestion of protein changes them to amine acids*

69*

Digestion of carbohydrate produaes glucose and other simple sugars*

n

intestine is a continuation of the digestive tube*

bile into the »»>»n
from

70*

Digestion of fats results in glycerol and fatty acids*

73*

The lymphatic system is part of the circulatory system*

75*

Because the amount of absorption from the small intestine is depen­
dent on the surface area of the epithelium, the folded inner Un-tug
ef the intestine and the finger-like villi are significant* They
increase the surface area*

76*

After digestion and absorption have taken place, the undigested
residue plus some unabsorbed food rad water pass into the large
intestine*

82*

Mo digestive ensymes are produced by the large intestine*

83.

Sons digestion and absorption occurs in the large intestine*

1U8

86*

Absorption removes most of the water f ran the large intestine,

87,

The food residues bee one fecal natter (feces)*
MEAN SCQBE 2,01 - 2.50

6,

Posteriorly (to the rear) the nouth opens into the pharynx or throat,

12,

The tongue aids in chewing by pushing the food between the teeth*
Tbs oheeks function in the sane nanner on the other side of the
teeth*

13*

The upper surface of the
papillae, at the base of

22*

The phaxynx lies just behind the nouth,

27,

The esophagus contains two layers of muscle tissue in its walls*

28*

Swallowing moves the food from the nouth into the esophagus and then
into the stomach,

29,

When swallowing occurs the food is moved to the back of the tongue*
The throat muscles contract and push it into the esophagus, which in
turn pushes it into the stomach,

30*

The movement of the food through the esophagus is caused by the
action of the muscle layers in the wall of the esophagus*

31*

The action of the muscle layers of the wall of the esophagus is
called peristalsis and is the sane sort of action that occurs when
one squeeaes toothpaste out of a tube*

32,

(During peristalsis) the muscles In front of tbs moving ball of food
relax, while those behind it contract*

33*

Both relaxation and contraction start at the upper end of the e s o p h ­
agus and continue toward the stomach* The food is pushed along by
the squeeslng action of the contracted wall of the esophagus,

1*7*

The snail intestine is smaller, though longer, than the stomach*

b8*

The pylorus, a ring-like band of muscle, separates the stomach and
the small intestine,

1*9*

The pylorus controls the passage of food from the stomach to the
small intestine*

tongue is rough and contains nunerous
which are taste buds*

Ib9

50*

The snail intestine is lined, like the stomach, with an epithelium*

6b*

The pancreas lies between the anterior portion of the snail Intestine
and the stomach*

65*

The pancreas is connected to the small intestine by a duct*

77.

The structure of the large intestine is basically the same as the
— ta~11 intestine*

78*

The large intestine has an epithelium lining the wall and two layers
of smooth muscle tissue that make up the bulk of the wall of the
tube*

79*

There are no villi in the large intestine*

8b*

A certain amount of undigested food plus the ensymes pass inte tbs
large intestine* The ensymes continue to act and the digested foods
are absorbed through its walls*

88*

The large intestine contains a large noaber of bacteria that act
upon and break down farther whatever is left over after digestion*

89,

The residue (in the large intestine) varies with the diet but
usually consists of cellulose from plant foods, tough connective
tissue from meat, and some fats*

92*

This (movement of feces into the rectum) exerts a pressure on the
walls of the rectum which causes a peristaltic wave to pass over the
entire large intestine to the anus*

9b*

(Peristalsis and straining provide the stimulus), the anal sphincter
relaxes and the fecal matter then passes through the anus*
MEAM SCQHB 2*51 - 3*S0

5*

The lips form the anterior (forward) boundry of the mouth* The
palate forms the roof and the cheeks form the side walls* The
floor is occupied by the tongue*

U*

The tongue is a muscular organ that fills the floor of the mouth*

lb*

There are four tastes:

15*

There are three pairs of salivary glands*

16*

One pair (of salivary glands) lies below and in front of the ears*

sweet, sour, salt »w h bitter*

150

17*

A duct fro* each (of the salivary glands lying below and In front
ef the ears) opens into the mouth opposite the second upper molar
tooth*

18.

The second pair (of salivary glands) lies In the posterior part of
the floor of the mouth*

21*

The salivary glands beneath the tongue have a number of duets that
open along the side of the tongue*

2lu

The tonsils and adenoids are embedded In the walls of the pharynx*

26*

The esophagus is lined with an epithelium*

38*

The wall of the stomach contains three layers of smooth muscle
tissue*

39*

The muscle tissue in the wall of the stomach squeezes the stomach
into a variety of shapes*

5b*

The intestinal walls contain two layers of smooth muscle*

56*

Connective tissue binds the various structures of the small intes­
tine together*

80*

The Junction of the small and large Intestines is not a direct end
to end union, for the small intestine connects with the large in­
testine a short way up from the anterior end of the large intestine*

81*

The end of the large intestine that extends beyond the comneetism .
(with the small intestine) has a small finger-like appendage called
the veradform appendix*

90*

O n odor of feces is due to the products of bacterial action*

91*

Peristalsis moves the fecal matter into the lower and of the intes­
tine and into the rectum at the posterior end of the digestive tube*

93*

Straining adds to the pressure on the feces by contraction ef the
diaphragm and the abdominal muscles*
MEAN SCORE 3*5l - b*50

Item numbers 19 and 20*

Content may be obtained f ram Appendix TT*

151

Principle I U - Respiratory organ systems evolved to effect adequate
gaseous exchanges between the organism and the environ­
ment* ati respiratory organs are characterised by baring
sufficiently large areas of thin, moist membranes richly
supplied with blood vessels to meet the oxygen Intake and
carbon dioxide outgo demands of the organism* The airbreathing organisms possess a system of tubes which permit
a more ready diffusion of gases to and from the respiratory
surfaces*
MEAM SCORE *S - 1»50

1*

Practically all animals must take in free oxygen and must get rid of
carbon dioxide*

2* 1he

immediate source of oxygen and the place of disposal of carbon
dioxide Is air for land animals and water for aquatic animals*

3*

The fundamental method of obtaining oxygen and resuming carbon diox­
ide is the same for both types (land and aquatic animals) though the
details of the mechanism may differ*

U*

The fundamental method of obtaining oxygen and removing carbon diox­
ide Is diffusion through a moist cell membrane*

5*

O s cell membrane must be moist or diffusion through It cannot occur*

Id*

Tissue fluids surrounds both capillaries and cells, so the oxygen
diffuses through this tissue fluid to the call*

20* The blood Is returned (from all parts ef the body) to the gills,
where carbon dioxide diffuses out into the surrounding water*

21*

Lungs are sacs contained within the thorax and their inner walls are
lined with a thin, moist, cellular membrane*

22i

Just beneath the moist cellular lining (of the lungs) are
of blood capillaries*

U9*

The exchange of oxygen and carbon dioxide in the lungs takes place
in the lining of the air sacs*

6U*

The inhaled air eventually reaches the air sacs, whose walls are
thin and moist and contain capillaries* The air contains a greater
concentration of oxygen than does the blood flowing through the
oaplllarles, so the oxygen diffuses into the bleed*

152

6J>*

The c ancentration of carbon dioxide in the air sacs of the lungs is
less than that in the blood, so it (the carbon dioxide) diffuses in
the opposite direction, that is, from the blood of the capillaries
to the air spaces in the air sacs*
MEAN SCORE 1,51 - 2*00

7*

The cell membrane of ameba is covered with the water in which the
ameba normally lives, and this water contains oxygen dissolved in
it.

8.

OoQrgen is also present in the cell (body of the ameba) where it is
used in cellular respiration* Cellular respiration removes the free
oxygen from the cell with the result that the concentration of coygen
within the cell is below that of the oxygen in the water outside.
Therefore, the oxygen diffuses from the water through the moist cell
membrane into the protoplasm of the cell.

9.

Cellular respiration (also) produces carbon dioxide, whieh accumulates within the cell in quantities greater than those present in
the water outside the cell membrane* Therefore, carbon dioxide dif­
fuses out ef the cell through the moist cell membrane into the
surrounding water*

10*

Some aquatic animals such as fish and lobsters have special struc­
tures called gills for obtaining oxygen from the water and for
releasing carbon dioxide.

U.

Cills are composed of many finger-like filaments through which blood
flews in capillaries*

12*

The outer layer of a (gill) filament is composed of a thin, cellular
membrane that lies over and is adjacent to the cellular wall of the
capillary.

13.

The aquatic animal lives in water which contains dissolved oxygen.
This water flaws over the surface of the filaments* The concentration
ef oxygen in the water is greater than in the blood flowing through
the capillaries, so diffusion of oxygen takes place from the water
through the moist cellular surface of the filament and through the
equally moist cellular wall of the capillary into the blood*

llu

Carbon dioxide is more concentrated in the capillary blood (ef the
gill filaments) than in the surrounding water and therefore diffuses
out (into the surrounding water)*

15*

Several moist oell membranes are involved in this mechanism (of
gaseous exchange in a gill bearing animal), but the underlying
principle is the sane as in the single-celled organise^

153

16*

Whan blood leaves the gills by way of the vessels It carries oxygen
to the tissues of the body*

17.

The cells of these (body) tissues use oxygen in cellular respiration
and thereby keep the concentration of oxygen In the cells reduced
below that of the blood flowing through the adjacent capillaries*
Diffusion again occurs and oxygen moves fron the blood through the
capillary wall, then through the cell nenbrane to the protoplasm of
the cell*

19*

Carbon dlooclde Is produced by cellular respiration (in aquatic gill
bearing animals) Just as in the case of the ameba, with the result
that the concentration in the cell is higher than la the blood flowlng through the capillaries* Diffusion takes place from the cell to
the capillary blood*

23*

The lining of the lungs is kept moist by the tissue fluid which al­
ways surrounds cells within the body*

2km

The lungs of land animals differ In complexity but all are basically
alike*

2$m

The human respiratory system is a type of complex respiratory
mechanism,

26*

The human respiratory system is composed of two major parts, tbs
first is a series of tubular structures that serve to transport air
into and out of the lungs* The second is a paired organ for absorp­
tion of oxygen and elimination of carbon dioxide* The two parts of
this paired organ comprise the lungs*

U6*

The wells of the air sacs (of the lungs) are thin and contain ■ mn/ wi*
of blood capillaries*

A*

Breathing consist of Inhaling and exhaling, or the movement of air
Into and out of the lungs*

55*

Inhalation results when the air pressure within the lungs falls below
atmospheric pressure, with the consequence that atmospheric pressure
pushes air into the lungs*

66*

Oxygen is transported by the hemoglobin contained in the red blood
corpuscles*

72*

Carbon dioxide is transported in the blood by both red corpuscles
and plasma*

73*

Carbon dioxide is produced in the cells of the body, where it is
picked up by the blood; then it is carried to the lung capillaries*
Prom the lung capillaries it diffuses Into the air spaces of the air
sacs and is breathed out*

15U

76.

In plants, the transport of oxygen to respiring cells and the trans­
port of carbon dioxide away fro* then is by diffusion*
MEAN SCQBE 2*01 - 2,50

6*

The simplest example of the mechanism (of gaseous exchange) is a
single-celled organism such as the ameba*

27*

Inside of the nose and extending back into the head is the paired
nasal oarity*

28*

The paired nasal carity is lined with a moist epithelium*

29.

The nasal carity opens into the pharynx*

30*

Ibe pharynx (throat) is a common passageway for air and food*

31*

The larynx opens into the pharynx just in front of the esophagus*

38.

The trachea is a cylindrical tube that extends from the larynx into
the chest carity*

1*0*

The trachea is lined with a moist, ciliated epithelium*

U2*

The trachea branches within the chest carity into right and left
primary bronchi, which are smaller, but otherwise similar to the
trachea*

U3«

The primary bronchi branch into secondary bronchi, which branch and
rebranch, erentually forming microscopic tubules*

Ijiu

The microscopic air tubules end In small air sacs*

5Q*

The thoracic carity contains the lungs*

56*

The pressure within the lungs is lowered by enlarging the thoracic
carity*

57*

Enlarging the thoracic carity is accomplished by mowing the walls of
the thoracic carity out and by lowering the floor*

60*

Exhalation is accomplished by the collapse of the lungs*

61*

The lungs contain elastic tissue which stretches when they expand
during inhalation* When the chest muscles and the diaphragm relax,
both the walla and the floor of the chest carity return to their
original position* This releases the stretching pressure on the
lungs and they collapse much like a leaky balloon*

155

63.

The lungs are not to be thought of as empty sacs similar to one
rubber balloon, bat rather to Millions of tiny balloons held to­
gether in a compact mass* Each of the tiny balloons has an air tube
connecting It to the main passageway.

67.

Hemoglobin is a red pigment that unites easily with oxygen, forming
the compound oxyhemoglobin#

68.

The oxygen also becomes separated from the hemoglobin easily under
certain conditions#

69#

In the lung capillaries the oxygen combines with hemoglobin, forming
oxyhmeeglobin and as such travels back to the heart to be distributed
throughout the body*

70*

finally it (the oxyhemoglobin) reaches the tissues of the body where
there is little or no oxygen* The oxygen then separates from the
hemoglobin and diffuses into the cells*

71*

(After the oxygen separates from the hemoglobin) the hemoglobin in
the red cells continues on into the veins through the heart and back
to the lungs; where it picks up another load of oxygen and carries
it to the tissues again*

75*

?here are no special structures to transport gases in plants though
there are openings such as the stomates in leaves and lenticels in
bark which permit the air to enter and leave#

77*

The carbon dioxide that the plant cells use in photosynthesis also
is transported by diffusion#
MEAN SCORE 2#5l - 3*50

32*

The larynx is a cylindrical structure with cartilage in its walls#

33*

In the male some of these cartilages (in the larynx) protrude, form­
ing the adam's apple#

3*Jo

Within the larynx are the vocal cords, which are connective tissue
bands which stretch across the cavity of the larynx#

35*

The glottis is the opening of the larynx into the pharynx*

36.

The epiglottis is a flap of oartilage that extends upward for a short
distance into the pharynx#

37*

During swallowing the epiglottis forms a cover for the glottis and
prevents food or water from entering the larynx*

156

39.

The walls of the trachea contain C-shaped cartilaganous rings that
keep the trachea permanently open*

I4
I.

The microscopic cilia on the pithelium beat toward the pharynx and
remove inhaled foreign particles*

U5«

The air sacs attached to the microscopic tubules superficially re­
semble a bunch of grapes*

1*7.

The capillaries in the walls of the air spaces of the lungs are
supported by connective tissue* some of which is elastic*

li8*

Whether the air sacs (of the lungs) are lined with an epithelium is
an open question*

51*

The thoracic cavity is divided into right and left pleural cavities
fay a thick median partition*

52.

Each pleural cavity contains a lung*

53*

The muscular diaphragm forma the floor of the thoracic cavity end
separates it from the abdominal cavity.

58.

The ribs lie within the walls of the thoracic cavity* Contraction
of certain chest muscles which are attached to the ribs causes the
ribs to swing out and produce a lateral enlargement of the cavity*

59*

Ihe floor of the thoracic cavity is made up of the muscular diaphragm.
It is dome shaped* with the dome extending upward into the cavity*
Contraction of the diaphragm flattens the dome and enlarges the space
within the cavity*

62*

The analogy with the balloon is not quite exact because each air sac
increases and decreases in slse during breathing* The entire lung
increases and decreases in aise accordingly*

71*. The xylem and phloem which make up the vascular bundles are the main
conducting tissues in plants*
Principle IV - Excretory organ systems evolved to
normality in
the chemical composition of fluids comprising the inter­
nal environment of the organism* In the multieellular
animals this is accomplished fay a system of tubes and
channels of varying degrees of complexity which permit
the outgo of metabolic wastes filtered from the blood or
other body fluids to the external environment*

157

MEAN SCORE ,5 - 1*50

1.

Metabolic processes in the body result in the production of useless
or harmful materials that must be eliminated*

U.

The nitrogen-containing wastes are excreted by the kidneys and leave
the body as urine*

£*

The kidneys also regulate the composition of the blood, particularly
with respeet to water and glucose*

llu

The blood carries waste materials from the body cells to the kidneys*
MEAH SCQBE 1*51 - 2,00

2*

Carbon dioxide produced in the cells is eliminated by the lungs*

3*

Food residue is eliminated as feces from the digestive tract*

6*

The (human) urinary system consist of two kidneys, two ducts known
as ureters, which drain urine from the kidneys, the bladder, which
is a reservoir for urine, and a single duct, the urethra, which
carries urine from the bladder to the outside of the body*

8*

Each kidney is composed of many small renal units which collectively
secrete the urine*

9*

Each renal unit consists of a small ball of capillaries, the glomeru­
lus, through which blood containing nitrogenous waste flows*

12*

Each renal tubule connects with other renal tubules which come from
other capsules to form a larger duct that empties into a chamber 1m
the central part of the kidney*

13*

The ureter is attached to the central chamber of the kidney*

15*

Within the klckieys the blood (containing nitrogenous wastes) flows
through the glomeruli within the many glomerular capsules*

16*

The pressure of the blood causes the fluid of the blood plus the
wastes and other substances in solution (mainly glucose) to filter
through the capillary walls into the cavity of the capsule*

17*

This liquid (glomerular filterate), which is really blood minus the
cells and the larger plasma proteins, passes into the tubule that
drains the capsule*

158

18*

As the liquid (glomerular filtersts) passes through the tubule the
cells lining its walls extract Most of the water and dissolved sub­
stances, leaving the wastes and sons water* This is urine*

19*

It (urine) leaves the kidneys by way of the ureter which carries it
to the bladder*

20*

The urethra carries it (urine) from the bladder to the outside (of
the body)*

23*

Carbon dioxide produced by cellular respiration nay be elininated
also by diffusion if it is not used in photosynthesis*

MEAN SCOBS 2*01 - 2*$0
7*
10*

The kidneys are bean-shaped structures about four and one-half inches
in length that lie along the dorsal wall of the abdonlnal cavity*
The glomerulus is surrounded by a microscopic cup-shaped structure,
the glomerular capsule*

11* A small tube, the renal tube is attached to the glomerular capsule*
21* Plants hare no special system to carry on the function of excretion*
22* The excess oxygen produced during photosynthesis diffuses out through
the stosiates of the leaves*
2lu

Other wastes are stored in various parts of the plant*

25* These wastes (of the plant) include oils, g u m , resins, organic acids,
tarnins, alkaloids, pigments and certain useless minerals*
AREA V
Utilisation of Matter and Energy:
Unit 3# Cells and the Internal Environment
The Specific Objectives
1* To gain an understanding of the structure and functions of
blood*
2* To knew the substances transported by blood and the functions
of these substances*
3* To understand the relationship between the evolutionary develop­
ment of organisms toward greater complexity and the development
of transport system*

159

Principles
1* Transport is a naans of bringing food, gases, hormones and
antibodies to place of utilisation* It is also a means of
removing wastes*
2* The fluids of the transport system constitute the immediate
environment of living cells*
3* m e evolutionary development of transport systems in organisms
is correlated with an Increase in organism also*
The Assignment
Biological Science Lecture Syllabus, pp* 1*2-55*
Principle I - Transport is a means of bringing food, gases, hormones and
antibodies to place of utilisation* It is also a means of
removing wastes*
HEAM SPORE *5 - 1*50
1*

The food that organisms use as a source of energy and for building
body structures must be transported from the place of digestion and
absorption to the various parts of the body where it is used*

2*

Ihe oxygen that is used to release the chemical energy contained in
food must be transported from its place of entry to the many places
of use*

3*

Many other substances essential to normal functioning of the body
must be carried from place to place*

!*• Finally, the wastes products of living processes must be removed*
5*

The chief method of transport used by all organisms, both plant and
animal, is diffusion*

6*

In some small organisms this (diffusion) alone is sufficient, but
in larger forms diffusion is not fast enough and additional means
of transport are necessary*

7*

These (additional means of transport) Include the blood and blood
vessels of animals, the air tubes of land animals, and the conducting
tissues of plants*

8*

Blood is made of a liquid portion, the plasma, and a cellular part,
the corpuscles*

86*

The heart pumps the blood through the blood vessels to all parts of
the body and back again*

160

92*

The heart is constructed of four chambers called the right and left
aurioles and right and left ventricles* A muscular wall separates
the right and left sides of the heart*

127*

The blood that picks up food from the digestive tract flows to the
liver*

129*

This (the fact that the blood from the digestive tract flows through
capillaries in the liver) enables the liver to remove the excess
glucose and amino acids before the blood goes to other parts of the
body*

130*

The capillaries are thin walled vessels that form an extensive net­
work throughout all body tissues*

135*

It is because of the large number of capillaries that oxygen and
food can be quickly and efficiently transported to cells and wastes
products can be carried away*

ll&»

The lymph capillaries also carry fat from the small intestine*
MEAN SCOHE 1*51 - 2,00

9*

The p l a s m is mainly water containing several substances dissolved
In it* among them blood proteins* mineral salts* food* wastes pro­
ducts* hormones* antibodies* and gases such as carbon dioxide and
oxygen*

13*

lymph is a part of the blood that has left the vessels and filtered
out Into the tissues*

id*

A red pigment known as hemoglobin* is contained within the corpuscles
and is the means of transporting ooorgen*

19*

When free oxygen is abundant it readily forms with hemoglobin a
loose chemical union which is as readily broken when the corpuscles
enter areas in the body where there is a scarcity of oxygen*

85*

The (human) circulatory system consist of heart* blood* blood
vessels* and lymph vessels*

87*

There are two circuits (to the circulatory system)* the pulmonary
and the systemic*

88*

The pulmonary circuit carries the blood to the lungs and back to
the heart*

161

89.

The systemic circuit carries the blood to all other parts of the
body Including tbs head, visceral organs, arsis, legs and body
muscles* The blood foilowing this circuit also returns to the
heart*

90*

The heart is a muscular pumping organ*

10U*

The contraction (of cardiac muscle) sends the blood into thevessels
and relaxation permits the heart to fill with blood again*

105.

The arteries carry blood away from the heart*

110*

Tbs mealiest (arteries) connect directly to the capillaries in
tissues of the body*

117*

The pulmonary artery carries blood from the right ventricle to the
lungs, where the artery breaks up into minute capillaries*

118*

The veins carry blood back to the heart*

122*

Blood flowing through capillaries in the tissues is collected by
the smallest veins* These connect to larger veins which in turn
connect to still larger ones* The largest veins flow into the
auricles of the heart*

128*

In the liver the blood from the digestive tract passes through a
network of capillaries before it returns to the heart*

131*

The capillary walls are a single cell in thickness*

132*

The capillary tubes are so small that red corpuscles must pass
through them in single file*

133*

The number of capillaries in any given area of tissue is very large*

136*

Scattered through the tissues along with the blood capillaries are
the lymph capillaries*

137*

The lymph capillaries are constructed in the same may as blood
capillaries, but they differ in that they are closed at one end*

138*

At their open ends the lymph capillaries interconnect like the twigs
of a tree, forming a branch which forms largerlymph vesselswhich
in turn unite to form large lymph ducts*

139*

The lymph ducts empty into certain large veins near the heart*

the

162

MEAN SCORE 2.01 - 2.50

10.

The blood proteins are a part of the blood and are not to be con­
sidered as food being transported.

.

15

The blood corpuscles include the red corpuscles, the white cor­
puscles, and the platelets.

Mi.

Stopping the flow of blood in one of the blood Teasels of the heart
prerents oxygen and food fro® getting to the heart muscle tissue.

5o.

The differences in human blood cause blood to be categorised Into
groups, ’
^hese are known as the 0 group, the A group, the B group
and the AB group.

58.

Both antigens and antibodies are present in normal blood, haring
been produced during embryonic development.

93.

The right auricle receives blood from the systemic circuit and sends
it Into the right ventricle.

9U.

From the right ventricle the blood Is pumped to the lungs.

95.

Ihe left auricle receives the blood returning from the lungs and
sends it Into the left ventricle, which pumps it into the systemic
circuit.

96.

Valves guard the openings between the auricles and ventricles.

97.

These valves (between auricles and ventricles) consists of flaps of
tissue that act like an ordinary door; that is, they open in one
direction only.

98.

When the blood flows from the auricles to the ventricles, the valves
are pushed open by the flow of blood, but when the ventricles con­
tract, the blood cannot flow into the auricles because the valves
are forced shut.

99.

The arteries that carry blood away from the ventricles also contain
valves.

.

100

.

The pulmonary valve is in the pulmonary artery and the aortic valve
in the aorta.

101

These valves (in the arteries) open when blood flows out of the
ventricles, but d o s e whan the blood attempts to flow back into
the heart.

102.

The walls of the heart are composed of a type of muscle tissue called
cardiac muscle.

163

103*

The outstanding feature of this (cardiac) muscle Is that it con­
tracts and relaxes alternately and tiythinlcally*

106*

The arteries are thick-walled blood vessels composed of three layers*
The Innermost layer is a thin, cellular layer called the endothelium*
The middle layer is thicker and is composed of smooth muscle* The
outside layer is composed of connective tissue*

108*

The largest arteries are those leading from the ventricles*

109*

Sis larger arteries branch and rebranch, gradually getting smaller
and smaller until they are quite minute in the tissues*

111*

The major systemic artery is the aorta that carries blood from the
left ventricle*

113*

Branches from the aorta at the bead carry blood into the head* One
branch goes up the right side of the neck and another up the left
side*

115*

Several arteries leave the aorta along the back and carry blood to
the stomach, intestine, and other organs in the abdominal cavity*

116*

In the pelvic region the aorta branches into two arteries which
extend into the legs*

119*

Veins have the same three layers that are present in arteries, but
they (veins) are much thinner walled*

121*

Valves that prevent the blood from flowing in a direction away from
the heart are found at intervals along the veins*

123*

Blood returns to tbs heart from the head by way of the jugular veins*

12ii*

HLood returning to the heart from the head and arms is carried by
veins that meet in the thorax to form the anterior vena cava which
opens into the right auricle*

12$*

The blood from the legs and back muscles and abdominal organs re­
turns to the heart by way of veins that join to form the posterior
vena cava, which lies along the mid-line of the back parallel to
the aorta*

126*

The posterior vena cava empties into the right auricle*

13lu

There are 2,000 capillaries in each square art111me ter of muscle*

11*0.

At intervals along the lymph vessels are lymph nodes or glands*

11*3*

Lymph glands also filter out and destroy bacteria contained in the
lymph that flows through the vessels*

1614

l^lu

The lymph capillaries drain some of the tissue fluid from the spaces
between the cells*
MB1M SCORE 2*51 - 3 . 5 0

11*

One of the blood proteins is fribinogen, which is important la
blood dotting*

12*

Plasma with fibrinogen removed is called serum*

111*

The volume of blood in an adult averages five or six quarts* depend­
ing on the size of the individual*

16*

The red corpuscles are small circular discs shaped somewhat like a
doughnut*

17*

There is no nucleus in the red corpuscles of mammals*

20*

The red corpuscles originate in the red bone marrow*

21*

During development they (red corpuscles) possess a nucleus which is
lost before the cells reach the circulating blood stream*

22*

Red corpuscles are fairly constant in number*

23*

In certain diseases the number (of red corpusdes) falls below nor­
mal* Such a condition is known as anmda*

2ii*

The white corpusdes are larger than the red* have a nucleus and
contain no hemoglobin, and some can move under their own power*

25*

White corpuscles originate in red bone marrow and lymph nodes*

26*

There are fewer white cells in the blood than red cells and they
vary more in number*

27*

The variability (of white cells) in number is linked up with their
primary function* which is to aid the body in combating infection*

28*

When bacteria enter the body* the white corpusdes d u s t e r around
and Ingest them*

29*

The white corpusdes move from place to place In the body within
the blood stream* but also they can leave the blood vessels end
move through the tissues*

30*

White corpusdes move by means of pseudopodia or protoplasmic pro­
cesses in the same manner as an anaha*

165

31.

The white corpuscles also engulf and digest bacteria as an ameba
does food*

32*

When an Infection Is present (in the body) the number of white
corpuscles increases*

33*

The Increase In white blood corpuscles Is used b y the physician to
determine whether a suspected infection is present, such as in the
diagnosis of appendicitis*

3h*

The platelets are small, colorless, round or spindle-shaped bodies
about one third the sise of red corpuscles*

35*

The platelets have an important function in blood dotting*

36*

A solid, crusty plug forms over a wound shortly after the blood
leaves the vessels and flews over the skin* This plug stops the
leakage of blopd from the vessels and Is known as a d o t *

37*

The chemical changes that result in the formation of the d o t from
the liquid blood start when the platelets disintegrate*

38*

The platelets are very fragile and burst whenever they come in con­
tact with a rough surface*

39*

When the platelets disintegrate they release a substance which re­
acts with the blood plasma to produce thrombin, and ensyme-like
substance, which in turn reacts with fibrinogen, a normal protein
constituent of the blood* The fibrinogen is changed into insoluble
fibrin* The red cells are caught in the meskerork to font a blood
dot*

hO*

The steps in the clotting of blood are as follows t
Thrombin 4 Fibrinogen -4
Fibrin
Fibrin 4- Cells
—►
Clot

hi*

A thrombus is a blood d o t in a blood vessel*

h2*

An esb d u s is a thrombus that is moving freely In theblood

stream*

h3*

Coronary thrombosis is the cause of many heart attacks, a thrombus
or e m b d u s plugging one of the blood vessels of the heart and
stopping the flow of blood*

h5*

A stroke may be caused by an embolus, or a thrombus, becoming
lodged in one of the blood vessels of the brain*

h6»

Hemophilia is a diseaas in which a person's blood does not d o t
quickly enough to prevent severe and sometimes fatal bleeding*

166

U7«

One tape of hemophilia Is hereditary and is thought to be due to
the lack of fragility of the platelets*

U9*

The blood of human beings differs* so it cannot be mixed indiscrim­
inately in transfusion* If different types are mixed* the red
corpuscles may clump or agglutinate and cause death* They may also
disintegrate with equally fatal results*

51*

Another type of blood group which is important in transfusion is
known as the Hh* The Bh group is not related in action to the O*
A, B and AB groups and must be considered separately*

52.

Understanding of the importance of the blood groups in transfusion
depends on an understanding of the antigsn-antibody reaction*

53*

This (antibody-antigen reaction) is based on the fact that when a
foreign protein is injected into an animal* the injected animal's
body reacts by manufacturing a chemical substance to counteract the
effect of the injected protein* The substance injected is called
an antigen and the substance produced because of the presence of
the antigen is called an antibody*

51u

The antlbody-antigen reaction is the basis for immunisation against
such diseases as smallpox* diphtheria* whooping cough and typhoid
fewer*

55*

To illustrate (the antibody-antlgen reaction)* diphtheria is caused
by a germ that produces a poison known as toxin* if the toxin is
injected into a human being or if it enters naturally because of an
infection* it acts as an antigen and stimulates the body to produce
an antibody known as antitoxin* The antitoxin neutralises the toxin

56*

The fatalities that result from mixing different types of blood in
transfusions are due to an antibody-antigen reaction*

57*

The antlgen-antlbody process differs in the blood groups from the
reaction described in the diphtheria example in that the antigens
do not stimulate the production of the antibodies*

59*

Certain hereditary determiners* the genes* cause development of
both antigens and antibodies (concerned In ordinary blood groups)*

60*

The antigens are present in the red blood corpuscles*

61*

There are two kinds of antigens* A and B*

62*

A person may have A antigen only* or he may have the B antigen only*
or he may have both A and B* It is also possible for a person to
have no antigens in the red corpuscles*

167

63*

If he has antigen A he belongs to blood group A. If he has antigen
B, he belongs to blood group B* If he has neither A or B antigen,
he belongs to group 0*

6U.

The antibodies are of two kinds and are known as "a" and "b".

65*

When red cells containing the A antigen are mixed with serum con­
taining the "a* antibody the blood cells clump*

66*

Likewise clumping occurs when B antigen is mixed with "b* antibody*

67*

It is obvious (from this) that a normal person of blood group A
having antigen a does not hare antibody "a*1* If he did the red
corpuscles would d u m p *

68*

However, he (a person with blood of group A) does have antibody "b"*

69.

A B-group individual lacks ”b" antibody but has antibody "a"*

70*

An AB individual has neither "a" nor "B" antibodies)*

71*

A person belonging to group O has both "A” and "B" antibodies*

72*

It is impossible to mix any two kinds of blood without uniting
either A with "a1
1 or B with "b". Nevertheless, blood types are
mixed in transfusion and one of them, known as the universal recip­
ient type, is able to take any of the other types* Another type,
the universal donor, can be used in transfusion to any of the
others*

73*

How is this (mixing of A with "a" or B with ”b M) possible? The
answer is to be found in the difference in quantity of blood be­
tween, the donor and recipient* The quantity of the donor 1s blood
that is transfused is much less than that of a recipient and is
quicldy diluted by the recipient1s blood in the blood vessels*
The antibodies of the donor are thus diluted to such an extent
that their effect is negligible*

7hm

The donor* s red corpuscles, however, are very quickly acted upon
by the antibodies of the recipient because of the relatively large
quantity of the recipients antibodies*

75*

In a transfusion it is necessary to be sure that the donor* s red
corpuscles do not contain an antigen that will react with the
recipient's antibodies*

76*

The universal donor is group
neither antigen (A nor B)*

77*

The universal recipient is group AB because Its serum contains
neither antibody ("a" nor "b**)«

0 because

its red blood cells contain

168

78*

The Kh blood group Is caused by the presence of an antigen known
as the Hh factor la the red corpuscles*

80*

There is no noxmal antibody to the Bh antigen but it nay cause anti­
body production if blood of an Bh positive person (having Bh antigen
la red cells) is transfhsed into an Rh negative person*

81.

If at sons future tine a second transfusion of Bh positive blood is
nade (into an Bh negative individual who has received a previous
transfusion of Rh positive blood), the Rh antigen reacts with the
antibodies and death nay result*

82*

Another serious consequence is caused when an Rh negative expectant
nother carries an Bh positive child* A few of the red corpuscles
containing the Rh antigen leave the blood strean of the unborn
child, get into the nother* s blood strean and stinulate the produc­
tion of antibodies* The antibodies of the nother diffuse Into the
blood strean of the snbryo and destroy the red corpuscles*

83*

Bh antibodies usually do not affect the first child, but subsequent
offspring nay suffer*

81**

Death of the enbryo nay result (frost affects of Rh inconpatibility)
or, if death does not occur, development nay be inpalred and an
anemic or f eebleninded child nay result*

91*

It (the heart) is a little larger than the person's fist and lies In
the thorax, the tip extending to the left of the mid-line*

107*

In the larger arteries there is a large amount of elastic connec­
tive tissue*

112.

The aorta extends forward from the heart and then bends backward
to continue to the posterior part of the body along the nld-llne
of the back just under the vertebral colunm*

llii*

The arteries that go to the arms also leave the aorta in this region
(of the backward bend of the aorta)*

120*

There is little n u s d e or elastic connective tissue In veins*

liil* Thq, lymph nodes are little masses of connective tissue filled with
whits blood cells*
11*2. The function of the lymph glands is to serve as a place for the
production of white blood cells*

169

MEAN SCORE 3.51 - U.50
Itea numbers U 8 end 79*
Principle U

Content nay be obtained from Appendix TT«

- The fluids of the transport system constitute the immediate
environment of living cells*
MEAN SCORE ,S - 1*56

1*

The capillaries lie immersed in tissue fluid that also surrounds
every cell In the body*

2*

Oogrgen and food materials diffuse from the blood through the capil­
lary walls into the tissue fluid*

3*

From the tissue fluid it (oxygen and food materials) diffuse into
the cells*

4*

Carbon dioxide and other waste materials diffuse from the cells
through tissue fluid into the blood of the capillaries*

5*

Tissue fluid is a part of the blood that filters through capillary
walls*

6*

It (tissue fluid) bathes the cells of the body and then passes into
the lymph vessels or back into the capillaries*

7*

The lymph capillaries drain some of the tissue fluid from the spaces
between the cells*

Principle H I - The evolutionary development of transport systems in
organisms is correlated with an increase in organism
sise*
MEAN SCORE *5 - 1*50

1*

The chief method of transport used by all organisms* both plant
and animal* is diffusion*

2*

In some small organisms this (diffusion) alone is sufficient* but
in larger forms diffusion is not fast enough and additional means
of transport are necessary*

170

3,

These (additional me&ns of transport) include the blood and blood
vessels of animals, the air tubes of land animals, and the con­
ducting tissues of plants*

iu

Unicellular animals such as ameba live entirely surrounded by water
that contains In solution the oxygen that the organism needs* This
oxygen diffuses from the water into the protoplasm (of the ameba)*

5*

Since the ameba is small, the oxygen (that diffuses Into the ameba* s
protoplasm) must travel only a short distance to reach all parts of
the individual* For this short distance the rate of diffusion is
adequate to keep the ameba continuously supplied with oxygen*
MEAN SCOBE 1.51 - 2*00

6*

Carbon dioxide, a waste product of metabolism, diffuses out of the
cell (ameba) into the surrounding water*

7*

Food diffuses in a similar manner* If the food is in solution out­
side the organism, it diffuses in* If it is not in solution, it Is
digested in a food vacuole within the cell and from this vacuole it
diffuses to all parts of the cell*
ABBA VI
Coordination and Adjustment:

Unit 1, Nervous Coordination

The Specific Objectives
1* TO understand that irritability is a fundamental characteristic
of living matter*
2* TO know that the structural and functional unit of the nervous
system of most animals is the neuron*
3* TO understand how nervous tissue functions to receive, conduct,
and associate nerve impulses set up as responses to specific
environaental stimuli*
li* TO understand that animal behavior has its basis in the quality
and degree of organisation and association of nervous elements*
5* TO realise that human intelligence is a consequence of the
quality and degree of organisation and association of nervous
elements*
Principles
1* A characteristic property of protoplasm is its capacity to
respond to stimuli of various kinds*

171

2.
3*

It*

The ability of organisms to adjust to their surroundings is
dependent upon the fundamental property of irritability in
llrlng things*
The nervous system is a mechanism which regulates and cooin dlnates the activities of various parts of the
body,
making it possible for the animal to act as an integrated
unit*
Nervous tissue has the capacity to "store up" the effects of
previous reactions to stimuli* This capacity is basic to the
establishment of instincts, habits and memory in animals*

The Assignment
Biological Science Lecture Syllabus, pp* 63-73*
Principle I - A characteristic property of protoplasm is its capacity to
respond to stimuli of various kinds*
MEAN SCORE *5 - 1*50
2*

Irritability is inherent in all living things*
MEAN SCOHB 1*$1 - 2*00

1*

The ability to receive stimulation and respond to it is called
irritability*

Principle IX - The ability of organisms to adjust to their surroundings
is dependent upon the fundamental property of irritability
in living things*

MEAN SCOBE *5 - 1*50
h*

Irritability is inherent in all living things*
MEAN SCOHB 1*51 - 2*00

1*

Living things adjust to the environment*

2* Living things are sensitive to their surroundings and respond to
them*

172

3*

The ability to receive stimulation and respond to it Is called
Irritability*

5.

Unicellular animals and plants respond to environmental stimuli,
though in general they have no structures specialised for this
purpose*

Principle H I - The nervous system is a mechanism which regulates and
coordinates the activities of various parts of the animal
body* making it possible for the animal to act as an
integrated unit*
MEAN SCOHB *5 - 1*50
lu

All animals including man have specialised tissues that aid in ad­
justing the individual to the environment*

5.

(These specialised) tissues which also coordinate the parts of the
body are the nervous and endocrine tissues* which in higher animals
are evolved into nervous and endocrine systems*

16*

The specialised cells that make up the nervous tissue and the nervous
system are the neurons*

75*

The brain functions in controlling and coordinating the actions of
the entire body*

81*

In many organisms special organs have developed that function in
receiving stimuli*
MEAN SCORE 1*51 - 2*00

1*

Life is characterised bgr activity*

2*

(The activity of life) may be the activity of growth, such as the
growth of roots and stems or the growth of man from infancy to
adult; or it may be the activity of parts of an organism; or it
nay be the activity of an animal moving from place to place*

3*

All (life) activity (of organisms) must be controlled and coordinated*

6*

The nervous system of man and other vertebrates has three major partes
(1) the central nervous system, (2) the peripheral nervous system*
and (3) the autonomic nervous system*

173

7*

These three systems axe interconnected* extend to all parte of the
body* and function something like a telephone system in a city*

8.

Messages received at any point can be quickly relayed to any other
part of the body*

9*

(But) just as a telephone message must go through "central”* so all
nervous messages must go through the central nervous system before
passing on to their Intended destination*

10*

The central nervous system

is composed of the brain and spinalcord*

13*

Nerves leave the brain and spinal cord and connect to muscles and
glands in all parts of the body just as telephone wires extend from
"central" to telephones in all parts of a city*

1U*

The peripheral nervous system comprises the nerves that extend from
the brain and spinal cord to muscles and glands in the outlying
parts of the body*

l£*

The autonomic nervous system consists of nerves that connect the
brain and spinal cord to the internal organs of the body such as
the heart* the stomach* and the intestines*

17*

Each neuron has a cell body containing cytoplasm and a nucleus*

18*

Prom this cell body two kinds of protoplasmic fibers extend*
are the dendrites and the axon*

19*

The dendrites usually extend away from the cell body in one direc­
tion* while the single axon stretches off in the opposite direction*

These

20* The axon connects with the dendrites of another neuron whose axon*
in turn* connects with the dendrites of another cell*
21*

(In this manner) a chain of neurons is formed that may reach from
the brain to the foot or to any other part of the body*

22*

Along (such) chains of nerve cells the messages (nerve impulses)
pass*

23*

The connection between an axon and a dendrite is known as a synapse*

2km

The simplest type of nervous interconnection within the body la the
reflex arc*

25*

(The reflex aro) illustrates the principle of nervous function*

26*

The reflex aro is composed of two neurons* a sensory neuron and a
motor neuron*

17U

33*

When an appropriate stimulus is applied to the end of the dendrite
near the surface of the body, a nervous impulse travels along the
dendrite from the point of stimulation to the cell body near the
spinal cord*

35*

At the synapse it (the iapulse) passes to the dendrite of the no tor
neuron and passes along it, through the cell body, e n d .then through
the axon of the no tor nerve*

36*

At the end of the notor axon it (the Inpulse) stimulates the muscle
to action* The muscle then contracts*

38*

The nerves are groups of nerve-cell fibers which extend Aram the
brain and spinal cord to all parts of the body*

57*

(Ihus) nerve impulses that enter the spinal cord by way of the sen­
sory nerves nay go to any notor neuron within the central nervous
system*

59*

Something controls the direction taken by any impulse, and this con­
trol makes possible integrated action within the organism*

61*

The structure which determines the direction that the impulse takes
is the synapse*

66*

All of the neurons of the brain are interconnected and all are con­
nected with the neurons of the spinal cord*

76*

All voluntary action is initiated in the cerebrum*

77*

One area (of the cerebrum) known as the notor area controls all
muscular action*

78*

Another area (of the cerebrum) is concerned with vision, another
with swell, and another with taste*

82*

Structures that function primarily to receive stimuli are called
receptors*

83*

External receptors which receive stimuli from the external anvironment include the eyes, the ears, the nose, the taste buds and the
sensory areas of the skin*

81**

Internal receptors receive stimuli from within the body and include
those in the tendons of the muscles and the semicircular canals of
the inner ear*

92*

The taste buds are on the tongue and are responsive to chemical sub­
stances in solution*

175

98*

D m effectors are tbs organs of the body that respond with action
whenever they are stimulated ty nerve impulses*

99.

There are two kinds of effectors - muscles and glands*

113.

A muscle contracts normally only when a nerve impulse Isdischarged
Into it*
MEAN SCORE 2*01 - 2*50

11.

The brain lies In the head, entirely surrounded by a bony covering,
the cranium*
r

12*

The spinal cord connects with the brain and extends down the middle
of the back within the vertebral coluen*

27*

The sensory neuron has a long dendrite, the end of which lies near
the surface of the body*

28*

It (the dendrite of the sensory neuron) extends from there (near
the surface of the body) to near the spinal cord where It enters
the cell body (of the sensory neuron)*

29*

The axon of the sensory neuron leaves the cell body and extends in*
to the spinal cord*

30*

Within the spinal cord It (the axon of the sensory neuron) connects
with a dendrite of the motor neuron* This connection is the synapse*

31*

The dendrite of the motor neuron Is short and Is almost Immediately
connected with its cell body, which also lies within the spinal
cord*

32*

The axon of the motor nerve passes out of the spinal cord to con­
nect with a muscle within the body*

3U*

(The impulse) goes through the cell body bo and through the axon*

37*

This action (as described) Is purely automatic like pushing a door­
bell, which initiates the passage of an electric current through a
wire* When the electric current reaches the doorbell, the bell
rings*

39*

The nerves enter and leave both sides of the central nervous system
at intervals*

U0*

Ihe twelve pairs of cranial nerves extend from the brain to various
organs in the head region such as the eyes, ears, throat*

176

ill.

The spinal nerves extend from the spinal cord to other parts of the

body*
li3.

Each (spinal) nerve Is attached to the spinal cord toy two roots*

UU*

The dorsal root (of the spinal nerves) contains sensory fibers that
bring inpulses Into the cord and the ventral root contains notor
fibers that carry inpulaes away fran the cord*

U5*

The dorsal sensory root has a ganglion containing the cell bodies
of the sensory neurons*

U6*

The spinal cord is conposed of two parts* the Inner gray natter and
the outer white natter*

51*

Both the cell bodies and the dendrites of these neurons (notor
neurons) lie within the grey natter of the cord*

52*

The axons of the dorsal sensory spinal nerves enter the cord froa
the spinal ganglion and nay connect directly with the dendrites of
the notor neuron*

53*

Usually* however* there are one or nore connective neurons between
(the axons of the sensozy neurons and the dendrites of the notor
neurons*)

5U«

The connective neurons nay extend fron the sensozy axon to the
notor dendrite at the sane level and on the sane side of the spinal
cord*

55*

They (the connective neurons) also nay extend across the cord to a
notor neuron of the other side* or they any go up or down the cord
and connect with a notor neuron at a different level*

56*

Sane (connective neurons) extend up into the brain*

58*

(However) none of the iapulses that enter the spinal cord goes to
all of the notor neurons*

60*

If nothing controlled the pathway taken by nerve inpulses* the
various parts of the body would react haphaaardly with no relation
to the action of other parts* Controlled* coordinated action
would be laposslbie*

62*

Whan an Iapulse reaches a synapse It is either reinforced or In­
hibited*

63*

The brain la a large mass of nervous tissue at the anterior end of
the spinal cord*

177

6iu

It (the brain) contains both gray and white natter*

65*

The gray natter (of the brain) Is composed of cell
white natter consist of axons and dendrites*

67*

The brain has three major parts, the brain a ten, the cerebellum and
the cerebrun*

68*

The brain stem is nade up nostly of axons and dendrites that extend
fro* the spinal cord to the cerebellun and cerebrun*

69.

The Medulla is the part of the brain stan that connects directly
with the spinal cord*

70*

The cerebellum Is a Mass of nervous tissue that lies at the back of
the brain over the Medulla and behind the cerebrum*

7km

The cerebruM is divided into two halves, the rightand left hemi­
spheres*

79m

Hearing also is dependent on the proper function of a certain area
of the oerebrun*

80*

The cerebellun functions in coordinating muscular action*

85*

The eyes receive light stimuli, which activate nerve impulses in
the optic nerve*

86*

These nerve impulses (in the optic nerve) when carried to the oere­
brun, result in the sensation of light*

87*

Tbs ears receive sound waves, which stimulate nerve impulses In the
auditory nerve*

88*

The auditory nerves carry the impulses to the brain, which inter­
prets then as sound*

89*

Oells lining the epithelium of the nose are sensitive to chemical
substances that become dissolved in the nasal fluids*

90.

When stimulated by chemical substances in solution in the nasal
fluids nerve impulses go to the brain by way of the alfactory nerve
and the brain interprets these impulses as man'll,

91*

Taste is closely linked to smell*

93*

The skin contains receptors for touch, pain, pressure, and the sen­
sations of cold and hot*

9km

The skin receptors are localised in certain areas*

bodies and the

178

95*

It Is possible to find then (skin receptors) by touching the skin
In different places with a fine pointed instrument*

111*

Every n u d e

in the body contains one or more nerve ending*

112*

The nerve endings (in muscle cells) are the ends of nerves that
bring nerve Impulses from the central nervous system*

116*

Heart muscle contracts rhythmically*

117*

Heart muscle can contract without nervous stimulation, though there
are nerve endings in the heart*

118*

The nerves that supply the heart function mainly in controlling the
rate of heart beat*

119*

One type of nerve carries impulses that stimulate the heart to beat
faster, and another type carries impulses that stimulate it to beat
more slowly*

123*

Nerves also connect with smooth muscle (cells)*

127*

(Glands) may secrete their substances into a tube and then into
some special organ or they may be without tubes or ducts and secrete
directly into the blood stream*
MEIN SCORE 2*51 - 3«50

U2*

There are thirty-one pairs of spinal nerves in man*

Ji7*

The gray matter contains the cell bodies of the motor neurons*

1*8,

The white matter is composed of cell fibers that extend up and
down the cord*

1*9,

The white color (of the white matter) is due to a fatty covering
material, called myelin, which surrounds each cell fiber*

50*

The axons of the motor neurons extend out of the cord within the
ventral motor spinal nerves*

71*

The cerebellum has an inner branching core of white matter and an
outer cortex of gray matter*

72*

The white matter (of the cerebellum) contains nerve fibers that
connect to cell bodies in the gray matter*

73*

The cerebrum also contains a core of white matter containing nerve
fibers and a cortex of gray matter*

179

96*

The sensation of cold will be perceived only If a cold needle touches
a cold receptor* If It Blisses the cold receptor, no sensation re­
sults unless It Is one of pressure or touch*

97.

The anno thing Is true for any of the other shin senses (that Is true
for cold receptors)*

100*

There are three kinds of noseless

skeletal, heart and snooth*

101*

The skeletal muscles are usually attached to the bones*

102*

They (the skeletal muscles) work in pairs, one of the pair pulling
a bone one way and the other pulling It in the opposite direction*

103*

Skeletal muscle Is wade up of elongated cells with many nuclei
scattered along the periphery of the cell*

10U*

A wnscle call is also called a muscle fiber*

106.

Each wuscle is wade up of many (of these) cells, some lying side
by side and sons end to end*

107*

The (wuscle) cells are held together by connective tissue that con­
tinues beyond the wuscle cells at each end to f o m a tendon*

108*

The tendon Is a tough cord of coxmective— tlssue fibers and attaches
the muscles to bone*

109*

When a wuscle contracts, the wuscle cells shorten, and this shortens
the entire wuscle and pulls on the tendons attached to each end*

110*

Usually one end (of the wuscle) rewe 1,ns fixed while the other end
aoves*

11U*

The heart is composed of cardiac wuscle*

115*

The (muscle) cells (in the heart) are striated like skeletal muscle
but they differ in that individual cells are branched and each cell
has one nucleus*

120*

The walls of the body tubes such as the digestive tract, blood
vessels, and bladder are eonposed primarily of sheets of smooth
muscle tissue*

121*

These (smooth) musole cells are not striated and each cell has but
ana nucleus*

12ii«

(Hands are eonposed of epithelial cells which produce particular
substances that hare a,definite function in relation to maintaining
life functions*

180

125*

'^he digestive glands that secrete digestive enzymes are examples
(of glands)*

126.

Glands may be one-celled or many celled*

128*

The endocrine glands are without ducts and, hence, are frequently
called ductless glands*
MEAN SCORE 3*51 - iu50

Item numbers 105 and 122*

Content may be obtained from Appendix II*

Principle IV - Nervous tissue has the capacity to "store up" the effects
of previous reactions to stimuli* This capacity is basic
to the establishment of instincts, habits and memory in
animals*
MEAM SCORE *5 - 1.50
13*

Learning consists of developing new modes of behavior which replace
inherited behavior or are superinposed upon it*

111*

Every organism starts life with an inherited behavior pattern*
This pattern is changed by learning, either by the suppression of
the inherited behavior or by the addition to it of new types of
behavior*
MEAN SCORE 1*51 - 2,00

1*

Coordinated actions constitute behavior*

2*

The nervous system works as a unit and coordinates all of the actions
of the body*

3*

Much (of this) integration is automatic and is the result of i n­
heritance, while some kinds of coordination are learned*

ii*

The inherited type of coordination is illustrated by the simple
reflex such as the knee jerk*

8*

Most of the lower animals depend entirely upon automatic reflexes
to coordinate their responses to envirommntal stimuli*

15*

The cerebrum is essential for this process (of learning)*

181

16.

How the cerebrun works in accomplishing learning, no one knows for
sure, but it involves receiving inpulses from the separate senses
and coordinating these into a meaningful whole*.

17.

The conditioned reflex offers a clue to the mechanism of the learn­
ing process*

23*

(This new association of stimulus and response) is a conditioned
reflex and also a learned response*

2lu

It is believed that almost all learning is dependent on this basic
mechanism*
MEAN SCORE 2.01 - 2.50

7*

Other examples of automatic behavior are the visceral reflexes that
control breathing, the action of digestive tract and the heart*

9*

Bees build intricate honeycombs without learning*

10*

Birds build nests exactly like their ancestors did, even though
they hare never seen them built before*

11*

Human infants suckle at the breast without learning and they show
a fear reaction if startled*

12*

They (human infants) also cry without training*

18*

lhe classical example of a conditioned reflex is that of salivation
in the dog*

19*

Hom a H y a hungry dog will secrete a quantity of saliva wham food
is seen or smelled* This is a reflex which involves the reception
of the stimulus through the eyes or nose, the conduction of that
stimulus to the brain, and the transmission of the stimulus to the
salivary glands* The glands are stimulated to secrete saliva,
which flows into the mouth*

20*

If a bell is rung at the same time that food is presented to the
dog, he will associate the ringing of the bell with the presence of
food*

21*

After repeated trials, the ringing of the bell without the presence
of the food will cause the dog to secrete saliva*

22*

(Thus) a new association of stimulus and response has been formed*

182

MEAN SCOHB 2«gl - 3.50
5*

If one sits with the lower leg hanging freely, a sharp tap with a
blunt instrument just below the knee will cause the leg to jerk
forward*

6*

The impulses stimulated by the blow travel up the leg along a sen­
sory neuron to the spinal cord* Within the cord they cross a
synapse to a motor neuron that carries the impulses to the leg
musoles, which contract and cause the leg to move*
ABBA VI
Coordination and Adjustment:

Unit 2, Chemical Coordination

The Specific Objectives
1* To understand that special chemical compounds called hormones
produced by certain tissues can modify the functional activities
of other tissues in the animal and plant body*
2* To realise that hormones act as chemical coordinators and in
conjunction with the nervous system of animals control and in­
tegrate the life processes of organisms*
3* To understand that hormones influence behavior in definite ways*
Principles
1* Hormones function in the coordination and integration of life
processes, such as metabolism, growth and reproduction, which
require prolonged stimulation rather than the rapid stimulation
characteristic of nervous action*
2* The systems of chemical and nervous coordination are intein­
dependent to a considerable degree*
The Assignment
Biological Science Lecture Syllabus, pp* 73-77*
Principle 1 - Hormones function In the coordination and integration of
life processes, such as metabolism, growth and reproduction,
which require prolonged stimulation rather than the rapid
stimulation characteristic of nervous action*
MEAN SCORE *5 - 1*50
1*

Adjustment of an organism to its environment involves not only the
proper response to external stimuli, but also the coordination of
activities within the body.

183

5*

The endocrine system coordinates the chemical processes*

7*

In general, endocrine responses are slow, cumulative ones which
stretch over considerable periods of time In contrast to nervous
responses which are almost Instantaneous*

10*

(The endocrine) glands secrete chemical substances directly into
the blood that flows through the glands*

12*

Hie hormones are carried by the blood to all parts of the body*

13*

The hormones affect only certain organs of the body*

ill.

In these organs (affected by the hormones) they produce a specific
type of reaction*

15>*

There are many different hormones, and each hormone usually pro­
duces one kind of reaction*

61*

(Ihe pituitary gland) Is called the master gland because Its hor­
mones regulate and coordinate many of the other endocrine glands
of the body*

70*

The pituitary hormones regulate the performance of other endocrine
glands, such as the thyroid, adrenal and sex gland*

82*

Both the estrogenic hormone and progesterone play essential parts
in the reproductive cycle*

83*

Plants produne hormones that are essential for growth*
ME1M SCQHB 1*51 - 2*00

3*

The autonomic nervous system and the endocrine system coordinate
internal activities*

6*

Examples of these chemical activities (coordinated by the autonomic
system) Include the oxidation of carbohydrates for the release of
energy, the maintenance of the proper amount of calcium In the
blood and the stimulation and Inhibition of the growth processes*

8*

The endocrine system is made up of several glands*

9*

(The endocrine) glands have no ducts*

11*

The chemical substances secreted by endocrine glance are called
hormones*

13h

16*

The action of the hormone secretin illustrates the may in which
hormones coordinate chemical processes in the body*

19*

If these two activities, the entrance of the food into the small
Intestine and the secretion of the digestive enzymes by the
pancreas, occurred at different times, the food and the enzymes
would not mix and digestion would not take place* A hormone,
secretin, coordinates the two events so that they occur approxi­
mately at the sane time*

22*

The major endocrine glands of man are the pancreas, thyroid, para­
thyroid, adrenal, pituitary, and gonads*

26*

A constant supply of islet hormone, insulin, is necessary for the
proper oxidation of glucose in cellular respiration*

27*

Insulin also plays an essential part in the storage of glucose in
the liver*

29*

The thyroid is a paired gland that lies near the trachea in the
neck region*

30,

(The thyroid) secretes the hormone thyroxin, which regulates the
rate of metabolism of the body*

38*

An overproduction of thyroxin increases the basal metabolic rate*

UU*

It (parathormone) regulates the calcium metabolism of the body*

h5*

Removal of the parathyroids causes the level of blood calcium to
to down, which in turn causes the muscles to contract spasmodically*

£2*

During times of stress such as in fright or anger the medulla (of
the adrenal gland) pours adrenalin into the blood*

53*

This (adrenalin in the blood during times of stress) stimulates the
heart to beat faster and causes the liver to release glucose* The
intake of oxygen is increased also*

5U*

The net result (of the affect of adrenalin in the blood during
stress is to increase carbohydrate metabolism and thus to increase
the muscular efficiency of the body*

55>*

The autonomic nervous system is connected to the medulla and stimu­
lates the production of adrenalin*

63*

An excess of one of the hormones (from the pituitary) during early
growth stages results in the production of giants*

68*

A deficiency of the pituitary hormone during early growth stages
results in the production of normally proportioned midgets*

185

71*

They (pituitary homones) control the secretion of m-nif by the
mawoary glands*

72*

They (pituitary hormones) also regulate the metabolism of carbo­
hydrates, fats and proteins*

7k*

Both (ovaries and testis) produce reproductive cells, but they also
produce hormones*

75*

The testes In the male contain two kinds of tissue* One kind is
concerned with the production of sperms* The other kind produces
the hormone testosterone*

77*

The normal development of the secondary sex characteristics In the
male is dependent upon the development of testosterone*

78* The secondary sex characters Include all of those physical and
mental traits that are associated with maleness, other than the
gonads, which are primary sex characters*
79• The ovaries of the female produce an estrogenic hormone*
80* The ovaries of the female produce progesterone*
81*

The estrogenic hormone Is responsible for the development of
secondary sex characters*

female

MEAN SCORE 2,01 - 2*$0
2*

The sense organs and certain effectors and the central and peri­
pheral nervous system take care of the adjustment of the whole
organism with its external environment*

k*

The autonomic nervous system is concerned primarily with the
mechanical processes such as breathing, circulation, and peri­
stalsis*

17*

Secretin coordinates the action of parts of the digestive system*

18*

The stomach mixes hydrochloric a d d with food and digestive enzymes
and eventually forces this mixture Into the small intestine* The
pancreas secretes digestive enzymes into the small Intestine, where
they digest the food*

20*

The hydrochloric acid from the stomach stimulates the cells of the
small Intestine to produce secretin, which passes Into the blood
stream and Is carried to the heart and then to all parts of the
body including the pancreas*

186

21*

Here (in the pancreas) the secretin stimulates the cells of the
pancreas to secrete digestive enzymes that immediately pass into
the Intestine by way of the pancreatic duct*

23* The pancreas has two functions* One is to secrete digestive
enzymes and the other is to secrete a hormone, insulin*
2lu

The endocrine part of the pancreas consists of small islands of
cells scattered among the cells that secrete enzymes*

25*

No ducts lead away from the islet cells* so the hormone is secreted
into the blood capillaries that course through the pancreas*

28*

The disease diabetes results if too little insulin is produced*

31*

The lack of a sufficient quantity of thyroxin in an infant or child
results in cretinism*

33*

Thyroxin deficiency In an adult causes an individual to be over­
weight and to be mentally sluggish* The heart rate is slower than
normal and the entire rate of metabolism df the individual is
slower than normal*

3lu

One type of goiter is associated with thyroxin deficiency*

35*

The production of thyroxin by the thyroid gland is dependent upon,
a sufficient supply of iodine*

36*

When iodine is deficient in the diet* the thyroid gland produces
less thyroxin than normal and also increases in bulk*

37*

The goiter is the overgrown (thyroid) gland*

39»

The individual (with an overactive thyroid) becomes irritable*
nervous* and overactive* The eyes bulge and the heart beats
irregularly*

k2m

(Each parathyroid gland) lies inbedded in or beside the thyroid
gland*

U3*

The hormone produced by these (parathyroid) glands is called
parathormone*

2|6*

Death results (following removal of parathyroids) if calcium is not
supplied*

hi*

The overproduction of parathormone causes calcium to be removed
from bones and teeth*

1*8.

The adrenal glands lie near the kidneys*

187

56*

If the medulla la removed the autonomic nervous system takes over
Its function*

57*

The adrenal cortex produces a hormone, cortin*

58*

Cortin regulates the sodium and potassium level of the blood and
tissues*

59*

The removal of the cortex (of the adrenal gland) Inevitably results
in death*

60*

The pituitary gland lies at the base of the brain*

62*

It is believed at the present time that twenty or more hormones are
produced by the pituitary gianH^

66*

If the excess of (pituitary growth) hormone production occurs after
normal growth has ceased the individual develops the fatal disease
acromegaly*

69*

The intellectual development of such undersized people (pituitary
midgets) Is normal*

73*

The gonads are the reproductive glands, ovaries and testis*

.76*

The cells of the testis that produce testosterone are called inter­
stitial cells*

8/4*

Plant hormones are known as auxins*

85*

A t the tips of s t e m , roots and buds and In young leaves cells
divide repeatedly and produce some growth*

86*

However, most growth (In plants) results from the elongation of
cells behind the tip*
\

87*

This elongation of cells (behind the tip) cannot occur unless auxin

Is present*

88*

It (auxin) Is produced In the dividing cells, at the tip of the
stems and roots, and diffuses to the cells behind the tip*

89*

(As a result of stimulation by auxin) these cells (behind the tip)
elongate and growth results*

90*

However, If the concentration of auxin is too great (In the region
of elongation), growth is retarded*

188

MEAN SCOBS 2*SL - 3*50
32*

Cretins are stunted* They hare short legs and in extreme cases
they waddle when they walk*
Their skin is leathery and their teeth
are defective*
They also are retarded mentally*

hO*

The parathyroids are usually four In number*

hi*

Each (parathyroid) gland is about the size of a pea*

h9*

(The adrenal glands) have two parts*

50*

One part (of the adrenal gland) is a central
the medulla*

coreofcells called

5xL*

The other part (of the adrenal gland) is an outer layer of cells
called the cortex*

6h*

(Skene giants resulting from an excess of one of the pituitary hor­
mones during early growth stages) attain a height of nine feet*

6£>*

The growth of these (pituitary) giants is symmetrical*

67.

In this disease (acromegaly) the bones of the hands* feet and face
Increase in thickness*

91*

Stasis can withstand a higher concentration (of auxin) than buds*

92*

Boots can withstand the least concentration (of auxin)*

Principle II - The systems of chemical and nervous coordination are inter­
dependent to a considerable degree*
MEAN SCORE *5 - 1*50
1*

The autonom ic nervous system and the endocrine system coordinate
internal activities*

MEAN SCOBB 1,51 - 2*00
2*

The autonomic system is concerned primarily with the mechanical pro­
cesses such as breathing* circulation and peristalsis*

3*

The endocrine system coordinates the chemical processes of the body*

189

U*

The autonomic nervous system Is connected to the (adrenal) medulla
and stimulates the production of adrenalin*

5*

If the adrenal medulla is removed the autonomic nervous system takes
- over its function*
AREA VII

Maintenance of the Species:

Unit 1* Reproduction and Development

The Specific Objectives
1*
2*
3*
lu
5*

6*
7*

To understand the processes of cell division and their biolog­
ical significance*
To realise the significance of the fact that gtll life comes
from pre-existing life under present environmental conditions*
To understand the essential difference between sexual and
asexual reproduction*
To understand the essentials of the structure and functioning
of the male and female reproductive systems*
To realise the importance of hormones in coordinating the pro­
cess of reproduction in animals*
To understand the essentials of human development*
To understand the Important features of reproduction and
development in plants*

Principles
1* New living organisms arise as the product of living organisms
of the same kind*
2* The basis for all reproduction is cell division*
3« Thera is an inverse relationship between the number of repro­
ductive elements produced by an organism and the degree to
which the offspring are protected and eared for*
U* The embryonic development of any organism la directed b y the
Interaction between the kind of protoplasm of the organism and
the intrinsic and extrinsic environmental factors*
The Assignment
Biological Science Lecture Syllabus* pp* 76-lOlu
Principle I - New living organisms arise as the product of living organ­
isms of the same kind*

MEAN SCORE *5 - 1*56
3*

Now it is believed that living things cone only from, other living

190

MEAN SCOHE 1,51 - 2,00
U*

The process of producing new individuals is called reproduction*

5*

Sons organisms reproduce sexually and others asexually*

6*

Asexual reproduction consists of the production of two or more in­
dividuals b y the division of one*

8*

In other cases the offspring separates from the parent as a smallersized replica* This is budding*

9*

There are some other forma of asexual reproduction (besides budding
and fission), but all of them are modifications of the same funda­
mental mechanism, which is cell division (mitosis)*
MEAN SCOHE 2*00. - 2*96

1*

Organisns age and die, and thus it is essential that new individuals
be produced*

2*

Tears ago it was thought that life could arise spontaneously out of
non-living matter, such as warms from putrefying flesh or frogs
from mud*

7*

In some oases (of asexual reproduction) the parent organism divides
into two offspring of equal size* This is known as fission*

Principle H

- The basis for all reproduction is cell division*

M E A N SPOKE 1*51 - 2*00

3*

Asexual reproduction consists of the production of two or more <»dividual s by the division of one,

6*

There are some other forms of asexual reproduction (besides budding
and fission), but all of them are modifications of the same funda­
mental mechanism, which is cell division (mitosis)*

7*

Sexual reproduction is similar to asexual reproduction in that cells
separate from the parent to develop into offspring, but it differs
in two respects*

191

.

8

(First) , the cells that separate from the parent (in sexual repro­
duction) are special cells that go through an intricate process of
development before they are ready for reproduction.

9.

(Second), the two kinds of cells (gametes) must unite in a process
called fertilization before offspring can develop.

.

10

There are two kinds of reproductive cells.
the other is the egg.

25.

In the process of fertilization the sperm penetrates the egg and
the nuclear material of both unite.

.

One is the spent and

166

Reproduction involving sex is found in almost all plants.

167.

As in animals, sexual reproduction In plants involves the union of
two gametes to produce a zygote which develops into a new individual*

195.

One of the male gamete nuclei unites with the egg to form the zygote.
This is fertilization.

197.

The zygote develops into the embryo.

MEAM SCORE 2.01 - 2.50
1

.

.

The process of producing new individuals is called reproduction.

2

Some organisms reproduce sexually and others asexually.

km

In some cases (of asexual reproduction) the parent organism divides
into two offspring of equal size. This is known as fission.

5.

In other cases (of asexual reproduction) the offspring separates
from the parent as a smaller-sized replica. This is budding.

12»

Gametes are germ cells (eggs and sperms).

13.

Gametes or g e m cells are produced in special organs called gonads.

1U.

The sperms are produced in testes in the male.

15.

The eggs or ova are produced in ovaries in the female.

2km

The union of the sperm and egg is called fertilization.

.

26

The fertilized egg is called the zygote.

29.

Generally only one s p a m unites with one egg (la the process of
fertilisation).

192

37.

(Thus)* internal fertilization is fundamentally the sane as axterfertilization in that water is the medium in which the sperms and
eggs unite*

50*

Human reproduction is sexual* The male produces the sperms and the
female produces the eggs or ora*

£7.

The undeveloped germ cells have the full complement of chromatin
material*

58*

When the reproductive cells are fully matured they have lost most
of their cytoplasm and half* or approximately half of the chromatin*

59*

The details of the chromatin loss (during maturation) are important
to heredity*

63*

In each testis the tubules containing the sperms converge toward
one side into a network of small tubes*

159*

Plants reproduce in the same manner as animals* that is* asexually
and sexually*

160*

Fission occurs

161*

Budding occurs in yeast*

16U*

Practically all plants develop spores or small cells with a pro­
tective coat*

165*

(The spores or small cells with a protective coat) separate from
the parent plant and develop into a new individual when conditions
favor growth*

183*

Hie reproductive structure that develops in the ovule contains a
number of cells* the most important of which are the endosperm cells
and the egg cell*

181u

The anther contains cells that develop into pollen grains*

190*

Following pollination the tube cell of the pollen begins to grow
downward into the stigma and through the style until it reaches the
center of the ovule*

193*

The nucleus of the generative cell divides* producing two nuclei
which become the male gamete nuclei*

19U*

When the pollen tube reaches the ovule* the end of the tube ruptures
and some of its contents enter the ovule*

196*

The other male ganete nucleus unites with the endosperm nuclei*

in the unicellular algae and bacteria*

*

4

193

203#

Growth of the embryonic plant requires energy which is obtained
from food stored in the embryonic leaves*
MEAN S00RE 2 . 5 1 - 3.50

it,

There are a few exceptional cases where the eggs can develop with­
out union, but this does not invalidate the general rule that in
sexual reproduction the usual procedure is for sperms and eggs to
unite before development of young can occur*

16*

The sperms are usually small and motile*

17,

The eggs are usually comparatively large and non—motile*

18,

The sperms and eggs are produced in organs within the body cavity
of the male or female and must be transported to the outside of
the body*

19,

This (transport of gametes to the outside of the body) is accoatplished by ducts or tubes that extend from the body cavity to an
opening at the surface of the body*

20*

In the male the ducts that transport the sperms are connected
directly to the testis*

21*

In the female the ducts do not connect directly to the ovaries, but
open within the body cavity*

22*

In some forms (of female animal) the open end of the tube is some
distance from the ovary so the egg drops from the ovary into the
body cavity and must be transported within the cavity to the open
end of the duct that carries it to the outside*

23* In other (forms of fmnales), such as the human being, the open end
of the duct is so d o s e to the ovary that the egg normally drops
right into the tube*
27*

Fertilisation is external (outside of the body) in aquatic animals
such as fish and in amphibians (frogs and toads), which reproduce
in the water*

28*

In these forms (fish and amphibians) the males and females come to­
gether in the water during the mating period* While they are to­
gether the female extrudes her eggs into the water
the — b1 —
releases his sperms* This results in a miirtng of the sperms and
eggs, during which time the aperms swim to the eggs and unite with
them*

19h

30.

Many a p a m a may attempt to penetrate one egg; but after one has en­
tered the egg a fertilization Membrane raises fron the surface of
the egg and prevents other s p e m s from entering*

31.

In internal fertilization the sperns and eggs unite within the body
of the female*

32.

This (internal fertilization) is usually accomplished by a mechanism
which injects the sperms into the reproductive ducts of the female*

33.

The male usually inserts the penis into the reproductive duct* which
normally branches and leads to the ovaries*

3U.

ihe eggs are released fron the ovaries and travel down the repro­
ductive ducts to meet the sperms coming up.

35.

Fertilisation (internal) occurs within the ducts (of the female
reproductive system).

36,

Inasmuch as the linings of the reproductive ducts are moist and the
sperms leave the male in a fluid known as semen* the sperms can
move upward within the tube at least partly by swimming*

38*

Only those animals in which there is internal fertilization* such
as reptiles* birds and mammals have become permanent land dwellers.

39*

The amphibians that live on land part of the time must return to
ponds and streams to reproduce because fertilization is external
and can be accomplished in water only*

i|0*

Variations in the usual fora of sexual reproduction include hermaph­
roditism and parthenogenesis*

h3»

(In hermaphroditism) usually two individuals are necessary for re­
production. A n exchange of operas occurs between the two individuals
and the eggs of both Individuals are fertilised*

U5.

In some animals the females produce eggs that do not require fertili^zation for development*

U6.

The development of eggs without fertilization is called partheno­
genesis*

U7.

The queen honey bee* (for example)* produces eggs that may or may
not be fertilised*

51.

The primary reproductive organs of the male are the two testes*

52.

The testes lie within the scrotum suspended from the lower sbilnman
between the legs*

•

195

53*

Each testis contains a number of coiled tubules ill which the sperms
are produced*

5U*

Die walls of each tubule (in the testes) contain reproductive cells
in various stages of development*

55*

Die
the
ity
are

56*

Die undeveloped g e m cells are more or less spherical and have the
normal amount of cytoplasm*

60*

Die mature male reproductive cell is known as the sperm cell*

61*

It (mature sperm) has a head containing the chroamtln tightly packed
inside* a middle piece containing a spiral filament* and a long
tail composed of cytoplasm*

62*

Die head (of the mature sperm) is oval as seen from the top or
bottom and flattened as seen from the side*

6U*

From this network (of small tubes) a number of small ducts lead out
of the testis and join the sperm duct*

65*

Die sperm duct passes upward into the abdoadnal cavity*

66*

Within the abdominal cavity it (sperm duct) curves forward to meet
the sperm duct from the other testis*

67*

Just before the union (of the sperm ducts) a duct from a seminal
vesicle opens into each sperm duct*

68*

Die fluid secretions of the two seminal vesicles make up part of
the semen*

(immature sperm) calls near the outer edge (of the tubules) are
least developed* those lying at the inner surface near the cav­
of the tube are the most developed* and the cells in between
at various intermediate stages*

semen is a fluid in which ejaculated sperms are immersed*
70*

The two sperm ducts open into the urethra*

71*

The urethra passes through the penis and opens at the

72#

Die prostate and bulbo-urethral glands secrete fluids into the re­
productive ducts*

73*

The secretions of the prostate and bulbo-urethral gi
those of the seminal vesicles make up the semes*

added to

196

7li*

The prostate gland lies at the juncture of the sperm ducts and the
urethra*

7*>*

The bulbo-urethral glands lie along side of the urethra*

76*

The sperms produced in the testes pass through the small tubules
into the epididymis*

77*

The sperms remain in the epididymis until ejaculated*

78*

When this (ejaculation) occurs they pass through the sperm duct
and then through the urethra to the outside*

79*

(When ejaculation occurs) fluid from the s eminal resides* prostate*
and bulbo-urethral glands is added as the sperms pass these glands*

80*

Each ejaculate is said to contain 200 to 300 million sperms*

81*

The female reproductive system consists of ovaries and reproductive
duets*

82*

The two ovaries of the female are flattened* oval bodies about an
inch in length*

83*

The ovaries lie attached to the side wall in the pelvic region of
the abdominal cavity*

81i*

Each ovary is filled with connective tissue cells and eggs in var­
ious stages of development*

85*

An epithelium of undeveloped reproductive cells covers the surface
(of each ovary)*

86*

At intervals groups of the epithelial cells sink into the connective
tissue of the ovary* One of them (epithelial cells) becomes the re­
productive cell while the rest cluster about it and become follicle
cells*

87*

The reproductive call increases in sise while the follicle cells
increase in number and form a large ball of cells* the follicle*

88.

A fluid filled cavity appears within the follicle* The reproductive
lies on one side of this cavity surrounded by a group of fol­
licle cells*

89*

Growth of the follicle continues while it moves into the ovary and
then back toward the surface (of the ovary)*

?0*

It (the follicle) eventually reaches the surface* from which it
projects as a bulge* It is now a mature follicle and the repro­
ductive cell is ready to be released*

197

91*

In the female the reproductive ducts consist of * vagina, a uterus
or womb and two oviducts*

92* The vagina is a tube about three inches long which opens at the
surface ofthe body at one end and connects with the uterus at the
other end*

93,

The uterus is also about three inches in length* It is a pearshaped organ with thick, muscular walls and a glandular lining*

9li* Die cervix is a projection of one end of the uterus into the vagina*
95*

At the opposite end of the uterus from the cervix, two oviducts
lead off to the ovaries*

96*

The oviducts do not connect directly to the ovaries butlead into
the body cavity adjacent to them*

97*

Finger-like processes surround the open ends of the oviducts, some
of which attach directly to the surface of the ovary.

98*

The discharge of the female reproductive cell, the egg, from the
ovary is known as ovulation*

99.

(When ovulation occurs) the follicle ruptures and the egg is
squeesed out*

100*

(After ovulation) the egg is drawn into the open end of the ovi­
duct almost immediately, apparently through the action of cilia or
hair-like processes that line the walls of the oviducts and beat
toward the uterus*

101*

In the human female ovulation begins at puberty, about the four­
teenth year, and ends at menopause, about the forty-seventh year*

102*

Generally one egg is released each month between these years (of
puberty and menopause)*

103*

The two ovaries alternate Irregularly in producing mature eggs*

l° k

Sometimes two or more ova are expelled at one time and if fertilized
produce fraternal twins or triplets*

105*

After the egg leaves the follicle the cells that line the follicle
increase in number and develop into a large, yellowish, glandular
structure known as the corpus luteum*

106,

if pregnancy occurs the corpus luteum persist until the latter part
of the pregnant period*

198

107-

If no pregnancy occurs the corpus luteum degenerates in about two
weeks*

108.

TTi* egg moves down the oviduct toward the uterus*

109*

If the egg is fertilized it begins development into an embryo and
travels to the uterus, where it remains until development is com­
plete*

HO*

If the egg is not fertilized it degenerates before reaching the
uterus*

111*

The vnywaw egg looses its ability to be fertilized within a rela­
tively short time after ovulation*

112*

The act of placing the penis of the male into the vagina of the
female is coitus or copulation*

113*

The purpose of copulation is to introduce semen into the vagina*

lilt*

After the sperms are deposited in the vagina, they may be drawn
into the uterus within a minute or two by the muscular action of
the cervix*

115.

The sperms move through the uterus into the oviducts*

116*

If ovulation has occurred, a sperm meets and fertilizes the egg in
the upper part of the oviduct*

117.

Sperms retain their vitality within the oviducts usually for no
longer then one or two days*

118*

In the human female uterine H e e d i n g known as menstruation occurs
at intervals of four weeks*

120*

Menstruation begins (in humans) between the twelfth and fourteenth
years and continues until the menopause*

121*

The duration of any one menstrual period varies from one to five
days*

122*

The average interval between periods is twenty-eight days*

123*

There is no exact regularity in the interval between periods*

12lu

The onset of menstruation coincides with the beginning of ovulation
at puberty*

125*

The cessation of both menstruation and ovulation usually occurs
simultaneously at the menopause*

199

The relation of oculation to menstruation is not mere coincidence.

127.

.

128

Both ovulation and menstruation are intimately linked in a series
of events related to the reproductive function of the female.

129.

We may consider ,the menstrual cycle as beginning when the pituitary
gi.wrf? that lies at the base of the brain secretes a hormone that
stimulates the development of a follicle within the ovary.

.

130

If the pituitary gland is removed the ovary ceases to produce re­
productive cells.

131.

As the follicle (in the ovary) develops it produces an estrogenic
hormone.

132.

ihe estrogenic hormone is carried by the blood stream to the uterus,
where it acts upon the uterine lining.

133.

The estrogenic hormone causes the lining of the uterus to grow and
develop.

13*u

The growth and development of the uterine lining Involves a thicken­
ing of the lining and an increase in the number, size, and secretory
activity of the giand^

135#

Under the stimulus of the estrogenic hormone the glands secrete a
nutritive substance which fills and dilates them.

136.

Blood vessels bring a copious supply of blood to the lining of the
uterus during the period of the thickening of its walls.

137.

The pituitary gland produces another important hormone, the luteiniz­
ing hormone.

138.

The luteinizing hormone directly affects the development of corpus
luteum tissue.

139.

The corpus luteum tissue replaces the follicle after ovulation.

*. The occurrence

11 0

na.

o f ,ovulation causes reduction of the supply of
estrogenic hormone (which has been providing the stimulus for uter­
ine development and thickening).

With the reduction in the supply of estrogenic hormone, another
hormone, progestrone, carries on the work of stimulating the develop­
ment of the uterine lining.

*. Progesterone is

11 2

11*3.

produced by the newly formed corpus luteum.

If the egg produced by the ovary is not fertilised the corpus luteum
maintains its production of progesterone for about two weeks, after
which it degenerates and ceases its endocrine function.

200

ii|l|r As a result of the absence of the corpus luteum hormone, the arteries
that carry blood to the lining of the uterus constrict*
11*5*

The constriction of the arteries to the uterus stops the flow of
blood and cuts off the supply of food and oxygen to the tissues of
the uterus*

11*6*

As a consequence of the lack of food and oxygen, the cells of the
uterine lining degenerate, they begin to slough off, blood Teasels
rupture, and the bleeding and destruction of the uterine lining
begins*

12*7»

The menstrual flow continues from one to five days, after which it
ceases and the lining of the uterus is repaired to begin the cycle
all over again*

U*8.

The beginning of repair coincides with the development of a new
follicle In the ovary and the renewed production of estrogenic
hormone*

11*9*

The estrogenic hormone stimulates the repair of the uterus*

150*

During the growth of the ovarian follicle, the estrogenic hormone
stimulates the development of the uterine lining, so that It be­
comes gorged with the nutritive secretion of the uterine gland*

151.

When the egg is released from the ovary, the corpus luteum hormone
takes over and keeps the lining of the uterus In condition while
the egg travels down the oviduct*

152*

If the egg is fertilised in the oviduct it begins to develop into
an esbryo that passes to the uterus and there becomes attached to
the wall*

153* The embryo uses energy for growth and development and lacking an
adequate supply of yolk, it must find Its nourishment elsewhere*
It finds it in the lining of the uterus*

15U*

The nutritive material secreted by the glands nourishes the embryo,
which at first attaches to the uterine wall and later sinks into it*

155*

The periodic growth and development of the uterine lining coincides
with ovulation, with the result that the young embryo has a favor­
able environment in which to develop*

156*

The
of the development of the uterine lining so that it coin­
cides with the release of the egg end the descent of the embryo Is
the function of the estrogenic hormone and progesterone*

157* If no pregnancy occurs, the uterus looses its developed lining and
starts all over again to be ready for the next ovulation*

201

158*

If pregnancy does occur, the corpus luteum continues to produce its
hormone long enough to insure the establishment of the enbryo within
the uterus*

162.

Some plants, such as the strawberry, send out long, leafless stems
or runners, itiich develop roots and separate from the parent plant*

163*

The potato is a tuber or underground stem that will produce a new
plant when planted*

168,

The flower is the reproductive organ of the flowering plant*

169*

The flower is attached to the end of the stem*

170* The flower consists of sepals, petals, stamens, and the pistils*
171*

The sepals are usually green, leaflike structures which enclose the
base of the petals at their point of attachment to the stem*

175*

The stamens font a circle within the petals and around the pistil*

176* The pistil occupies the center of the stem end*
177*

The parts of the flower concerned directly with reproduction are
the stamen and the pistil*

178*

Each stamen has two parts: the anther and a long upright support,
the filament, which holds the anther aloft*

179*

The pistil is usually flaskshaped, having a bulbous base, the ovulary,
from ifcioh the neoklike style projects upward*

180*

The tip of the style is called the stigma*

181*

Ihe ovulary contains one or more ovules*

182*

In each ovule a reproductive structure develops*

185*

Each pollen grain consists of a generative cell and a tube cell and
is covered by a drought-resisting coat*

186*

When the pollen grains are mature the anther breaks open and the
pollen is freed*

187*

The wind blows the pollen of some flowers to other flowers*

188*

In other plants visiting insects become covered with the pollen and
transport it to other flowers*

189*

When the pollen reaches a flower, some of the grains land on the
stigma of the pistil* This is known as pollination*

t

202

191*

The tube nucleus Moves along the pollen rube just behind the growing
tip*

192*

The gen eratire cell follows the tube nucleus through the cytoplasm
of the pollen tube*

198*

The outer layer or layers of the ovule develop into the protective
covering*

199 .

The embryo and the endosperm surrounded by the protective covering
caaprise the seed*

200*

The embryo is composed of one or two large embryonic leaves (the
cotyledons), one embryonic root and one embryonic stem*

201.

When the seed is mature and environmental conditions are favorable
it will germinate*

202*

Gemination Involves growth and development of the embryonic root
into the ground and growth and development of the embryonic stem
into the air above the ground*

20U*

The cotyledons or embryonic leaves are thick with stored food which
is digested by enaymes*

20£*

After digestion the food is transported to the growing root acid
stem, where it is used for energy and building of protoplasm*

206*

Developawnt of both roots and stems involves the differentiation
of embryonic (meristem) tissues into the mature tissues found in
adult roots and stems*

208*

Leaves develop on the stem (of the plant)*
MEAN SCORE 3*51 - h.$0

Items number 1*1, U2, hh, US, U9, 119, 126, 172, 173, 17U, and 207*
tent may be obtained from Appendix II*

Con­

Principle III - There is an inverse relationship between the number of
reproductive elements produced by an organism and the
degree to which the offspring are protected and cared
for*
Syllabus assignment contained no material related to Principle III*

203

Principle 17 - The embryonic development of any organism is directed by
the interaction between the kind of protoplasm of the
organism and the intrinsic and extrinsic environmental
factors*
MEAN SCORE *5 - 1*50
1.

The fertilised egg or aygote develops by a process of cell division,
growth and differentiation into a new individual*

2*

Food is necessary to supply materials and energy for developomnt (of
the aygote)*

3*

During the early stages of development the embryo's energy require­
ments are met largely by means of yolk stored in the egg*

10*

(In mammals) the problem of "nourishing the developing sygote
solved by the retention of the eabiyo within the body of the
and the development of a temporary organ, the placenta, that
nects the embryo with the tissues of the mother* The embryo
its nourishment directly from the mother*

is
mother
con­
gets

lit*

Embryos obtain the energy they use for growth and developarent by
oxidation of food in the same manner as adult organl sms*

35*

All animal embryos, from the simplest forms to the most complex,
must develop in water to prevent dessication and to insure that
pressures will be equal from all sides*

W#

The first step in the development of a human embryo is fertilisation*
MEAM SCORE 1*53. - 2*00

iu

In all animals yolk is manufactured in the ovary and included within
the egg prior to fertilisation*

5*

Some animals such as the fish and the frog have relatively little
yolk, and this is used up during the early stages of development*

6*

After the yolk is gone the young embryo must depend on its environment for food*

7*

(In forms having very little yolk) a mouth and intestine develop
very early, with the result that they begin to feed quite early in
development on small particles of food in the water*

20k

8*

Other forms, (such as reptiles and birds) produce eggs that hare
sufficient yolk to last then throughout their period of development*

9.

Some animals, including man and other mammals, produce very little
yolk for nourishment of the embryo*

H.

Both the mother* s blood stream and that
of theembryo flam into the
placenta* The two blood streams do not unite, but flam side by
side, and food originally eaten by the mother and carried In her
blood stream diffuses into the blood of the embryo to be carried te
its tissues*

15*

Cellular respiration (In embryos) could not go on without a continuous supply of oxy gen*

16*

The carbon dioxide produced by embryos must be excreted*

17*

In aquatic animals whose young develop in the water, the oaqrgem
(required by the embryo) comes (directly) from the water and dif­
fuses into the cells of the embryo*

18*

Eventually
gills develop in aquatic animals, but prior to their
development the oxygen diffuses from the surrounding water directly
into each individual cell*

19*

Carbon dioxide diffuses out of the cells (of aquatic embryos) into
the water*

23*

In the earliest stages of development (of the land egg) the oxygen
of the air diffuses directly into the pells and the carbon dioxide*
diffuses out, but eventually a respiratory organ develops that
serves to receive oxygen for the embryo from the atmosphere and to
remove the carbon dioxide*

2ii*

This (respiratory) structure (in the lend egg) consists of a seelike membrane that grows out of the embryo and cosms to lie just
beneath the porous shell* Blood vessels of the embryo carry blood
to and away from it* While the blood flams through the membrane,
oxygen diffuses into it from the air and carbon dioxide diffuses
out*

28,

in manuals the placenta serves as the respiratory organ for the
embryo,

29*

In mamm als, the mother's blood, which flows into the placenta,
carries oxygen as well as food and this oxygen diffuses into the
embryo's blood stream* Carbon dioxide diffuses Into the placenta •
in the opposite direction*

30*

All developing embryos produce waste materials other than carbon
dioxide and these must be removed from the body*

205

33*

In mammals the placenta serves to permit wastes In the embryo's
blood stream to pass into the mother's blood stream*
The kidneys of the mother excrete (the metabolic wastes from the
embryo's body)*

36*

Normal symmetrical development would be Impossible unless the pres­
sure of the environment were equally distributed over the surface
of the embryo*
«

37*

The buoyant action of water plus Its fluidity makes it an ideal
medium for maintaining equal pressures*

38*

Land animals do not develop in ponds and streams, but they do
develop surrounded by water*

51*

After fertilisation, the zygote continues to move down the oviduct
to the uterus*

52*

During its passage down the duet it (the zygote) goes through a
process of cell division*

53*

The first division of the zygote results in the formation of two
oalls of equal size* These divide in turn to produce four cells*

5U*

By the time the embryo has reached the uterus repeated cell divisions
have resulted in the formation of a ball of cells* all qpproximately
equal in size*

56*

The bias tula differentiates at this time into an inner cell mass
and an outer layer of cells*

59*

Soon after entering the uterus the eafcryo attaches Itself to the
wall of the uterus*

69*

Upon entering the uterine wall (the embryo) begins to grow* obtain­
ing its nourishment from the dissolved uterine lining*

71*

Qastrulation Involves the differentiation of the inner cell mass
into endoderm and ectoderm*

85*

Ihe placenta functions as an organ of exchange between the mother's
blood stream and that of the embryo*

86*

Food and oxygen pass from the mother's blood into the blood of the
embryo* while waste move In the opposite direction*

107*

(9ms)* all food* oxygen* and wastes that enter and leave the embryo
do so through the umbilical cord*

206

MEAN SCORE 2.01-2.50
12*

Mammals have special milk-secreting glands, the mamnary glands,
that function to nourish the young after birth*

20#

In land animals such as birds and reptiles, the eggs are not ianersed
in water but are laid on land*

21*

In land aninals the air of the atmosphere is the source of oxygen
and the place of disposal of carbon dioxide*

22*

The eggs of birds and reptiles are surrounded by a proous shell
that permits the air to enter and leave the egg*

2$.

The sac-like membrane (under the shell of the land egg) is also a
receptacle for the disposition of other waste products*

31*

In aquatic aninals waste diffuses out of the embryo into the sur­
rounding water*

32.

In birds and reptiles the sac-like membrane (Just beneath the shell)
serves as a receptacle for such (metabolic) wastes*

39*

Early in development in all land animals including reptiles, birds
and mamoals, a sac-like membrane grows out and surrounds the
embryo* This sac is called the amnion*

Uo*

The amnion fulls with water and immersed in this water is the
eabrye*

111*

It is the "bag of waters" that burst prior to the birth of the
human child*

h7m

Mammals do not hare a protective cover immediately surrounding the
sygote, but the embryo develops within the body of the mother,
which serves ably as a protective cover*

h9*

3he spent unites with the egg in the upper third of the oviduct*

50*

The fertilised egg is called the sygote*
A cavity appears in the cneter of the ball of cells, which is now
called a blastula*

57*

The outer layer of cells fonts a hollow sphere within which the
inner cell mass is suspended*

58.

The inner cell mass eventually gives rise to the body of the human
embryo and the outer cell layer develops into membranes surrounding
the embryonic body*

207

6L.

This (attachment of the embryo) happens on the ninth or tenth, day
after fertilisation*

62.

It is suspected that the entoryo secretes an ensyme that digest the
uterine tissue, for the wall of the uterus disintegrates beneath
the embryo*

63*

The embryo promptly sinks into the depression so formed*

61**

It tdces about one day for the embryo to penetrate completely into
the wall of the uterus*

65*

A clot fills the depression above the embryo, which is now effec­
tively sealed in*

66*

Disintegration of the uterus continues (until) the embryo becomes
surrounded with digested uterine tissue, which is absorbed and used
to nourish the growing eabryo*

67*

Up until the tine the embryo penetrates the uterine lining, it re­
mains the same sise as the original sygote*

68*

This (failure of the embryo to Increase in sise) is due to the
limited amount of food the original egg contained*

70*

As it (the embryo) grows, it continues to destroy the tissue around
it and expands into the space thus provided*

72*

2he endoderm is formed when the outer layer of ceGLls separates from
the rest of the inner cell mass*

73*

The ectoderm differentiates at the same time (as the endoderm) and
is made up of the cells remaining after the endoderm has split off*

7U*

The endoderm forms a hallow sphere that remains attached to the
inner cell mass along the surface from which it separates*

79*

The human eabryo and eventually the human infant develops from the
embryonic disc*

83*

A third layer of cells, the mesoderm, develops within the embryonic
disc between the eotoderm and the endoderm*
placenta is composed of two parts, embryonic and maternal*

88*. As the outer cell layer (of the placenta) enlarges, fingerlike pro­
jections, known as villi grow out from its outer surf ace into the
uterine spaces formed b y the disintegration of the tissue of the
uterus*

208

89-

Blood Tassels that fora in the embryo grow down into the villi.
Through then the blood of the embryo flows into the villi and then
back into the enbryo,

90,

The rilli occupy spaces in the uterine wall into which the Mother's
blood vessels eeqpty, and it is here that the exchange of food,
oxygen and wastes occur- Other blood vessels drain the spaces.
Thus, asternal blood is carried to the uterine spaces and assy,

91,

That part of the uterus that contains the blood spaces in which the
villi lie is the asternal part of the placenta,

92-

It will be reneabered that early in developasnb the bias tula is a
hollow sphere of cells. The inner cell aass is attached at one
point andhangs into the cavity of the blastula,

106,

The nabl 1 leal cord connects the developing eabryo body to the villi,
diich develop into the placenta,

108,

All of the tissues, organs and systems that develop in the eabryo
and aake up the adult body cone froa the three enbryonic layers,
the ectoderm, endodera, and mesoderm,

109,

The ectoderm develops into the nervous system and the outer layer
of skin,

110-

Froa the ando derm is developed the lining of the digestive tract
and its glands, the liver and the pancreas,

111,

The lungs also develop froa the ando derm as an outfolding froa the
gut,

112,

The a e s o d e m develops into the muscles, bones, connective tissue,
blood vessels, and other organs that aake up the bulk of the body
and lie between the outer layer of skin and the inner t
of the
digestive tract.

KEAN SCORE 2-51 - 3-S0
13-

The mammary elands are located on the ventral surface of the body,

26,

When the young bird or reptile hatches, the aembrane (beneath the
shell; is separated and discarded,

2?#

In nawnale, among which the young develop within the body of the
aother, the s a d ike aeabrane starts to develop, but it never becoass
functional.

20?

1*2.

The outer covering of the zygotes varies in

different animal forms*

1*3.

Many fish have no covering of any sort over their fertilised eggs*

1*1*.

Frogs, toads and other amphibians secrete aJelly-like substance
that swells in contact with water and serves as a protective layer
for the early stages of development*

1*9. Reptile eggs are covered with a leathery shell*
1*6.

Bird's eggs have ahard, brittle shell*

60.

The point of attachment (of the mnbryo to the uterus) varies, but
usually it occurs high on either the front or back wall*

75.

2his endodermal sphere is called the yolk sac*

76*

The ectodermal cells of the inner cell mass hollow out so that two
hollow balls of cells lie adjacent to each other*

77.

The area where the ectoderm lies next to the endoderm is Known as
the embryonic disc*

78*

‘
ihe embryonic disc is a circular disc-shaped structure composed of
the two layers, ectoderm and endoderm*

8u.

The ectoderm that extends outward and upward from the embryonic disc
arches over it (embryonic disc) to form a dome-shaped roof*

81.

The ectoderm forming the roof over the embryonic disc is the

82*

The cavity within the amnion is the amniotic cavity*

8b*

The mesoderm spreads out, covering the ectoderm of the
the endoderm of the yolk sac*

93*

A layer of cells, the endoderm, separates from the free surface of
the inner coll mass and forms a hollow sphere called the yolk sac*

9k*

The ectoderm, or rem ainder of the inner cell mass hollows out to
become the amnion*
-

95*

The point where the two spheres (yolk sac and amnion) come together
is the embryonic disc*

96.

(Thus), the embryonic disc is composed of two layers of cells, the
ectoderm and endoderm*

and

210

97*

(The embryo develops from the embryonic disc) and the remainder of
the tissues, Including the amnion, yolk sac, and outer cell layers,
become the membranes that function in aiding development*

98*

The membranes that function In aiding development are discarded at
birth*

99*

During early development the embryonic disc raises upward relative
to the amnion so that a circular groove appears around Its edge*
Actually the groove Is caused by the downward growth of the amnion
along the edge where It attaches to the embryonic disc* It (the
amnion) grows downward and folds under*

100.

As it (the amnion) continues folding under, the peripheral groove
deepens and cuts under the edge of the embryonic disc* This Infold­
ing constricts the endoderm into two parts*

101*

The upper part contained within the ectoderm of the embryonic disc
is the gut, the forerunner of the digestive tract*

102*

The lower part (of the endoderm) remains the yolk sac*

103*

An outfolding of endoderm occurs in the floor of the embryonic gut
Just behind its attachment to the yolk sac* This sacllke eutfolding grows into a mass of tissue, the body stalk, which actually
becomes the umbilical cord*

lolu

The amnion enlarges as it grows* As the edges of the amnion fold
under the embryonic disc, they form a tube that extends away from
the lower surface of the embryonic disc* This tube Is called the
umbilical cord*

105*

unhll Inal cord contains the yolk sac and blood vessels*

113*

After four weeks of development the embryo Is only a little over
one-eighth inch long*

HU*

After four weeks of development the eabryo possesses same fish—like
characteristics* It has gill slits and a tail*

13-5*

The arms and legs begin to form as

116*

At six weeks It (the eabryo) is a half-inch in length, the arms and
legs have grown and the head is quite large in relation to the rest
of the body* The parts of the head are becoming differentiated*
gill slits and tall are still present*

117*

By eight weeks the human form Is attained though the length Is only
about one inch*

buds on the sides*

211

118*

From this tine (attainment of human form) on it (the ambzyo) is
known as a fetus*

119*

Further development (of the fetus) consists of growth and c o m ­
pletion of the development of the parts already formed*

120*

The heart starts beating at five or six weeks*

121*

Birth occurs about nine months after conception*

122*

During pregnancy the growth of the fetus is accomplished fcy an en­
largement of the uterus*

123*

(The uterus) becomes approximately fifty times larger (during preg­
nancy) than the original sise*

12li*

By the ninth month the uterus extends to the lower end of the
sternum*

125*

The other organs within the abdominal cavity ere compressed and
displaced as a result of the growth of the uterus*

126*

The fetus assumes a characteristic position within the amnio tic
cavity in which the elbows* knees and hips are flexed* the feet
and arms are crossed* the back bent and the head rests on the
chest and is turned to one side*

127*

At birth the most common position is head downward* although the
reverse position may be assumed with the buttocks near the vaginal
opening*

128*

Die fetus also nay lie crosswise*

129*

When the fetus is crosswise or with the buttocks nearest the vaginal
opening birth is more difficult*

130*

Childbirth occurs approximately 280 dgys after the last menstrual
period or at the time of the tenth missed mensis*

131*

Labor consists of a series of contractions of the Involuntary
muscles of the uterus*

132*

The contractions of the involuntary musoles of tha uterus cause the
"pains" of child birth*

133*

Contractions of the abdominal musoles assist in forcing the fetal
membranes* containing the liquid and the child* against the
cervix*

212

13b*

The fetal membranes or "bag of waters" burst and the child is ex­
truded#

13!>#

Further uterine contractions after the birth of the child expel the
placenta and fetal membranes#

136*

(After birth) the umbilical cord is severed d o s e to the child*s
abdomen#.

137#

Severing the umbilical cord separates the child from the placenta#

138*

The stump of the cord becomes the naval*
AREA T O
Maintenance of the Species:

Unit 2, Heredity

The Specific Objectives
1# To understand the mechanism of heredity#
2# To recognise the social and economic significance of the science
of genetics#
Principles
1# Chromosome behavior and distribution during the maturation of
the germ cells determines the number of different kinds of
germ cells an organism can produce*
2# Genes determine the potentialities of organisms* The environ*
ment determines the extent to which these potentialities can
be realised#
The Assignment
Biological Science Lecture Syllabus# pp* 10U-138#
Principle I - Chrnosome behavior and distribution during the maturation
of the germ cells detentions the number of different kinds
of gorm cells an organism can produce#
MEAN SCORE *5 - 1*50
2*

In both sexual and asexual reproduction cells separate from the
parent or parents to develop into the next generation#

3*

The cells that separate from the parents and develop into the next
generation represent the only protoplasmic link between parents
and offspring#

213

iu

It follows that whatever passes from parents to offspring to cause
the development of parental traits in tbs offspring most be contained in the germ cells*

6*

Chromatin contains chemicals known as genes which govern the develop­
ment of the individual*

21*

Thus, in sexual reproduction, the offspring inherit some of their
traits from the father and some from the mother*

25#

The part of maturation that is particularly significant in heredity
is reduction division*

32.

Each of the new cells (resulting from reduction division) which
contains one chromosome of each farmer pair, becomes a germ cell,
either an egg or a sperm, depending on whether it is produced by
the male or the female*

33*

The primary result of the reduction division is to separate the
paired chromsomes*
MEAN SCORE 1,51 - 2,00

1,

Heredity is the transmission of traits from parent to offspring*
The controlling substance that passes from parents to offspring is
the chromatin*

18*

Both daughter cells have the sane number and the same kind of
chromosomes and the same kind of genes*

19*

Since genes control the development of traits in offspring, it is
apparent that in this kind of reproduction where the offspring get
exactly the same kinds of genes as were present in the parents,
the offspring become exactly like the pa rente*

20*

In sexual reproduction genes from two parents are eoatbined during
fertilization to produce the new individual*

22,

In order to understand how the offspring Inherit some traits from
the father and some from the mother one must follow the history of
the genes during development of the germ calls within the parent*

23*

The germ cells or gametes are produced in the testis of the male
and in the ovaries of the female*

2lu

The development of these cells (gametes) is fundamentally the same
in both sexes (male and female) so far as its effect on heredity is
concerned*

21U

26.

The calls in the gonad (either ovary or testes) undergo a division
daring their development into mature g e m cells that is similar to
but not exactly like mitosis*

27.

Thus (in reduction division) the chromatin granules for* threads*
which shorten and thicken into chromosomes as in mitosis* but in
this case the threads do not duplicate.

28.

(Instead of duplicating themselves as in mitosis) the threads (chromo­
somes) pair*

30*

(In reduction division in humans) the twenty-four pairs of chromo­
somes line up on the equator of the spindle* the paired chromosomes
separate* and each member of a pair goes to the opposite pole of
the spindle*

3hm

The paired chronosasms are homologus or alike; that is* they have
genes for the same traits#

35*

If we use the letters A* B* C and D to designate chromosomes an
■w-im*i having eight chromosomes in a germ cell before maturation
will have two A*s* two B's* and so forth because each (kind of)
chromosome has another like it. During reduction division the
chromosomes will pair as follows AA* BB* CC* DD* When cell divi­
sion (reduction division) occurs* two cells will be formed* each
of which will contain A* B* C* D* This represents the chromosoma
content of a germ cell* The same kind of reduction occurs in the
production of gametes by the other sex* so its germ cells also con­
tain A* B* C, D. When fertilisation occurs* the chromosomes of the
two kinds of g e m cells are united and the sygote contains AA* BB*
CC* DD* This is the same nxafcer as in each of the parents* but
half cams from one parent and half from the other*
MEAM SCOBS 2.01 - 2.50

9m

The particular number (of threads) that form is constant for any
species of organism* tout varies among different species*

10*

Each thread duplicates Itself to become a double strand of chromatin.

11*

The genes are arranged in linear order on the chromatin thread*
like beads on a string* therefore the duplication of the chromatin
thread also duplicates the genes*

13*

These short rods are called chromosomes*

16.

The double chromosomes separate* one going to each pole of the
spindle.

215

17*
*

The cytoplasm constricts in the middle of the cell between the two
groups of chromosomes, with the result that two cells are formed*

29*

In a human cell prior to pairing there are forty-eight chromosomes,
after pairing there are twenty-four pairs*

31*

Following separation of the paired chromosomes the cytoplasm con­
stricts as In mitosis and two cells are formed*
MEAN SCORE 2*51 - 3*50

7*

in
reproduction, such as mitotdLc minary fission, the single
cell divides into two daughter cells* Before division takes place
the chromatin is scattered in a granular form throughout the nucleus*

8*

When division (binary fission) begins the chromatin arranges itself
so that a number of threads are formed within the nucleus*

12*

The double threads then shorten and thicken until short, doable rods
are formed*

Hi*

While the chromosomes are forming, the nuclear membrane disappears
and a spindle forms in the cneter of the cell*

15*

She double chromosomes line up with their long axes parallel to
the equator of the spindle, so that one chromosome is on one side
of the equator toward one pole and the other chromosome on the side
of the equator toward the other pole*

36*

The Illustration of the inheritance of a single pair of characters
(a monohybrid cross) as given in the syllabus, pages 106-107*

37*

The illustration of the inheritance of two pairs of characters (a
dihybrid cross) as given in the syllabus, pages 107-106*

Principle II - Genes determine the potentialities of organisms* The en­
vironment determines the extent to which these potenti­
alities can be realised*
MEAN SCOBE *5 - 1.5Q
33*

(In other words) each gene may produce an enzyme or it may produce
a substance which in turn produces an enzyme*

216

3U*

(These) enzymes regulate the thousands of chemical reactions which
take place in an organism and it is conceivable that a change or
cessation of one or more of these chemical reactions would result
in variations of the appearance or behavior of an individual*
MEAN SCORE l*5l - 2,00

7.

There are two kinds of chromosomes in every cell of sexually repro­
ducing organisms* They are the sex chromosomes called the X and Y
chromosomes* and the autosomes*

17*

Occasionally an individual will appear among offspring that differs
from any that have been produced before*

18,

Sometimes the appearance of an offspring that differs from any that
have been produced before is the result of the recombination of
recessive genes and sometimes it is due to environmental causes pro­
ducing a change in the chromosomes or genes*

19*

Chromosomal or gene changes that result in the appearance of a new
trait are called mutations*

20*
21,
23,

Gene mutations are those in which a single gene is involved*
Chromosome changes include large sections of chromosomes and involve
many genes*
The principles of heredity apply to man as well as to other organisms*

27*

Another method
(of obtaining knowledge of human heredity) isthrough
the use of statistical analysis*

30*

(In previous discussions)* it has been stated that the presence of
certain genes is responsible for the development of certain traits
in an individual*

32,

It has recently been shown by various workers in genetics that it is
possible for a single gene to control a single biochemical reaction
and that this control is probably due to a control of the production
of enzymes*

U5*

It should be appreciated that genes which determine the absence or
presence of a certain characteristic are often influenced by genes
which determine other characteristics*

122,

For this reason (relationship between heredity and environment) it
Is almost impossible to attribute an individual *s intelligence
wholly to heredity or to environment; rather it is a product of both*

I

123*

217

It Is probable that heredity sets the H a l t s of mental development,
while environment acts within these limits*
MEAN SCORE 2,01 - 2*50

1.

If a red snapdragon Is crossed with a white snapdragon, the off­
spring are pink because neither gene of the pair determining color
is camlnaut*

2.

(In snapdragons Individuals) heterosygous (for color) always shew
an intermediate condition between the parents when one apir of
genes only is concerned*

3*

(A type of inheritance similar to color in snapdragons) Is illus­
trated In crosses between Negro and white races Involving skin
color*

U*

There are genes for black skin and genes for white skin and none
are dominant*

5*

The Fi*s of a black and white cross are all mnlattoes of the same
intermediate shade*

6*

Hie F 2's of a black and white cross show a gradation of color from
pure black to pure white.

8*

The sex chromosomes control development of sex traits, while the
autosomes control the development of other body (somatic) traits*

9m
10*

The X chromosomes contain most of the female determining genes*
The Y chromosomes contain few or no sex-determining genes*

11*

The autopomes contain male-determining genes as well as the great
majority of genes affecting somatic characters*

12*

Females have two X chromosomes plus autosomes*

13*

Males have one X and one Y chromosome plus autosomes*

llu

During development the presence of two X chromosomes in the zygote
results in the development of a female because the genes for the
devel opaient of the female sex are present in greater strength than
the genes for development of the male sex in the autosomea*
If * zygote contains XY chromosomes the male genes in the autosomes
control development and a male results*

218

16*

The T chromosome has no effect; rather it is the development of the
extra X that makes possible the development of the male sex*

22*

An example of chromosome changes is deletion, where a piece of
chromosome becomes lost#

2km

The study of human heredity is particularly difficult for several
reasons* First, there are usually only three or four generations
of humans produced within the lifetime of one investigator* Second,
the number of human offspring is very small compared with the number
of offspring produced by plants and animals* Xhird, individual and
social resistance act as barriers which limit experimentation with
human mating#

26*

Some of this information (about human heredity).has been obtained
through the study of family histories, which are interpreted on the
basis of the laws of heredity originally discovered in other or­
ganisms#

31*

The actual relationship between a gene and the trait which it deter­
mines, however, has been a matter of conjecture#

35*

Albinism is an example of a characteristic in man which is a result
of the failure of a certain chemical reaction to take place*

36,

One of the amino acids is oxidised to form a substance called dopa*
In normal man and women dopa is converted to a pigment called
melanin which colors the eyes, skin, and hair* This change from
dopa to melanin is attributed to a dominant gene*

37*

The recessive gene evidently is unable to complete this chemical
reaction (dopa to melanin) and, consequently, an individual who
has two of these recessive genes will be an albino#

38*

This person (an albino) will have very light skin, white hair, and
pink eyes, because of an almost total lack of pigment in these
structures#

U3*

The exact mode of inheritance of eye color is not known, though it
is thought that several genes are involved#

1*6,

Here is a situation (above) where the genes for albinism inhibit
the potential development of eye color despite the fact that genes
for eye color are, present#

1*8,

It is because of the complex interrelationships among genes that
many of the things we would like to know about human inheritance
have not been found out#

219

60.

Apparently one pair of genes can express Itself differently dependIng on the sex. In males the gene Is dominant, while in females it
is recessive.

63.

This abnormality (red-green color blindness) is inherited as a sexlinked recessive.

61*.

A sex-linked character is one in which the genes are on the Z
chromosomes.

65.

The gene for color blindness is recessive to the normal gene; there­
fore two genes for color blindness - one on each Z chromosome - must
be present in the female to cause color blindness.

66.

If only one gene is present (for color blindness) in the female*
she is not color blind, but is a carrier, and can pass the gene on
to one-half of her offspring.

67.

The male, on the other hand, with one X and one Y chromosome, will
be color blind if the defective gene is located on the Z chromosome.

68.

The Y chromosome (of the male) carries no genes for this trait
(color blindness).

69.

Since only one gene is neoessaxy to cause color blindness in nales*
more males are colorblind than females.

81.

According to this hypothesis (that handedness is due to a single
pair of genes with lack of complete dominance) those individuals
who are homoaygous for right-handedness will be right handed* those
homosygous for left-handedness will be left handed. Heterozygous
individuals, however, nay be ambidextrous* right or left handed*
depending upon environmental Influences, which of course* are to­
ward right-handedness.

82.

Handedness among homoaygous individuals may occasionally be changed
by environment, but such a change, according to some psychologist*
may result in nervous disorders such as stuttering.

81*. All three blood groups (ABO, MN and Bh) are inherited independently
of each other.
85.

One explanation of the Inheritance of the A, B, O blood group is
that three genes are involved.

86,

Gene A causes the development of antigen A in the red blood cor­
puscle; gene B causes the antigen B to develop; gene 0 causes the
development of no antigen.

220

87*

These three genes (responsible for the ABO blood groups) are pre­
sent In the population in general, but any one Individual has at
most only two of the three*

88*

Neither gene A nor gene B Is dominant to the other but both are
dominant to gene 0*

lull*

For the sake of simplicity, however, Bh positive isaaid to be 1nberlted as a dominant trait and Rh negative as a recessive trait*

lu9.

If the Bb4* blood oells of the child diffuse into the blood stream
of the eother, they cause in the mother's blood the production of
antibodies*

HO*

If these antibodies (from the Bh- mother's blood stream) diffuse
back into the infant's blood stream and comm in contact with the
Infant's Bh antigen, the red blood cells of the Infant may be
destroyed and the child either dies or has severe anemia and
jaundice at birth*

119*

One thing la obvious, even If we asanas that mental ability Is in. heziteds environment has a definite role to play*

120*

A potential genius, If completely Isolated from society, would mot
develop his mental capacity to the point where It would be recog­
nised as such*

11*1** Phenylketonuria is an example of a single gene's being responsible
for the production of an ensyme, the presence or absence of which
determines normality or feeble-mindedness*
Ui8*

Studies of twins show that when one fraternal twin is feahl o->wiwried,
the other Is feeble-minded in one-fourth of the eases; in Identical
twins, however, when one Is feeble-minded, the other la feeble­
minded in practically every ease*

l£3*

lb the geneticist, the segregation of genes la the most reasonable
explanation for the occasional appearance of dull children In bright
families*

155*

Another test (of the relationship of environment and heredity to
Intelligence) Is the measurement and correlation of the intelli­
gence of adopted children and their foster paretns and comparison
of the results with those derived frcm studies of true parents end
their children*

157*

Studies of Identical twins show that they are more alike in intel­
ligence than fraternal twins even when reared in different environ­
ments*

221

18-1*

Our knowledge of genetics has enabled us to improve the stocks of
our domesticated animals and plants to a considerable extent*

183•

Biologist have long advocated the adoption of measures aimed at
controlling the spread of known hereditary defects throughout the
population as part of an eugenics program*

186*

Before any progress can be made toward the betterment of mankind
through genetics* society must understand the facts placed at its
disposal by scientist and must develop a willingness to use these
facts for the good of society*
MEAN SCORE 2*51 - 3«5Q

25*

Despite the difficulties* much progress has been made (la human
heredity) and a long list of Inherited traits is known*

28*

Th-i* method (of statistical analysis in the study of human heredity)
involves observations of the frequency with which a certain trait
appears In a given population (the gene frequency)*

29*

Geneticist have established certain mathematical formulae by
of which these data (gene frequencies) can be Interpreted to
dicate the mode of inheritance for a particular trait* This
thetical mode of inheritance is then further investigated by
of the trait in closely related individuals*

39*

The color of the eyes is due to granules of pigment deposited through
the back part of the Iris*

UO*

Blue color is due to granules which reflect blue light* Brown eye
color.is caused by the presence of brown pigment In front of the
granules responsible for blue eye color*

ill*

Other eye colors (besides blue and brown)* such as gray or green*
are due to. the varying amount* of brown pigment laid down on the
granules reflecting the blue light*

U2*

In the case of individuals where no pigment is present* the eyes
appear pink because of the reflection of the color of the blood in
the blood vessels of the eye*

UU*

Brown is generally considered dominant over blue*

U7*

Ihis example (of the Inhibiting effect of albino genes) nay give
you an Insight into the complexities of the interrelationships
existing between the actions of the genes*

means
in­
hypo­
studies

222

U9#

Skin color is determined, b y the pigment in the skin*

50.

There is much pigment in the skin of Negroes and little in the skin
of whites*

5l#

in the Negro white crosses the offspring are mulatto and intermediate
in color*

52*

When two mulattoes are crossed, the offspring are various degrees
of pigmentation*

£3*

It is thought by some geneticist that many pairs of genes are re­
sponsible for tbs Inheritance of skin color*

£U*

One explanation (for the inheritance of skin color) is that two
pairs of genes are involved*

££•

A black skin results froa the genotype AABB and a white skin froa
the genotype aabb* A mulatto would have the genotype AaBb*

56*

The skin of an individual having a genotype Aabb would be inter­
mediate between mulatto and white and simil arly a genotype or AAfib
would result in a skin color Intermediate between mulatto and black*

57#

If this hypothesis (for the inheritance of akin color) is accepted,
it can also be inferred that the genes are passed from parent to
offspring as they are in an ordinary dihybrid cross where there is
a lack of dominance in both pairs of genes*

58*

There are small color differences within the white race which may be
caused by the influence of only a single pair of genes* The darker
pigmentation apparently is dominant over the lighter*

59*

Some baldness may result from disease, but much of it is a hereditary
characteristic*

61*

This type of inheritance (as in baldness) is known as sex-limited
or sex-influenced inheritance and explains why more men than women
are bald*

62*

In red-green color blindness the person cannot distinguish between
red and green colors*

70*

If a colorblind man marries a normal woman, all his sons and
daughters will be normal, but one-half of his daughters will be
carriers*

71*

These (carrier daughters) may pass the gene to one-half of their
sons, who will be o d o r blind*

223

72*

A color blind nan vlll transmit this trait (colorblindness) to
soma of his grandsons through his daughters*

73.

Total color blindness is also hereditary, as is the inability to
distinguish between various pastel shades of color*

7U«

The mods of inheritance of these types of color blindness (total
and pastel) has not been definitely established*

75*

Surveys show that approximately 7 per cent of the white population
is left handed*

76*

Studies of closely related individuals indicate that there is a
correlation between the handedness of parents and their offspring*

77*

Wien both parents are right-handed, about 6 per cent of the children
are left-handed*

78*

When one parent is right-handed and the other left-handed about 16
per cent of the children are left-handed*

79m

When both parents are left-handed, about 5>0 per cent of the children
are left-handed*

80*

Since two right-handed parents may have left-handed children and
two left-handed parents may have right-handed children, one hypo­
thesis is that handedness is due to a single pair of genes with
lack of dominance*

83*

There are at least three blood groups in men the ABO group, the MN
group and the B h group*

89*

It has been discovered that the A and B antigens are present not
only in the red blood cells, but also in every cell of the body*

90*

Experimental work in the field of plastic surgery Indicates that
better results are obtained in the grafting of tissues from one
individual to another when these individuals are of the same ABO
type* This may be due to the same principles involved in blood
transfusions*

91*

The A and B antigens are soluable in the body fluids*

92*

Bis degree of solubility (of A and B antigens in the body fluids),
however, varies with different individuals* In about 70 per cent
of the population the presence of these antigens can be detected
in the saliva*

93*

(The individuals in which the antigens can be detected in the saliva)
are known as secretors, the remainder non-se eretors*

22k

9iu

The condition whereby antigen* nay be detected in the saliva i#
inherited as a sinple dominant trait.

95.

Under certain circumstances criminal investigators are able to deter­
mine the ABO type of secretors by analysis of saliva on recently
discarded cigarette stubs*

96*

In the Inheritance of the MN group one gene (M) censes the develop­
ment of the M antigen while another gene (V) causes the production
of the N antigen*

91.

Neither of the genes (for M and N antigen) is dominant.

98.

The MN antigens are not known to produce any harmful effects as a
result of blood transfusions regardless of the MN type of the donor
or recipient*

99.

A knowledge of the mode of inheritance of the ABO and MN blood
groups is applied quite often in cases of disputed paternity*

.

100

.

101

.

Another of the inherited blood groups is the Bh complex*
One explanation of the inheritance of the Bh factor is the presence
of three pairs of genes on a single pair of chromosomes*

102

The six genes (involved in the inheritance of Bh) when contained in
all possible arrangements produce eight different Bh blood types*

103.

Although these eight (Bh) types are due to different genotypes,
seven of them are collectively known as Bh*-, the eighth type, as
Bh—.

105.

According to this simplified explanation, an Bh* Individual would
have a genotype or RR or H r and an Bh- individual would have a
genotype of rr*

.

106

About 85 percent of the white population is Bh* and 15 per cent
is B h—*

107.

Knowledge of the inheritance of the Bh group is important because a
mating between an Bh* father and an Bh- mother will produce in at
least one-half of the cases, offspring that are Bh**

.

108

.

111

The presence of an Bh* child within the body of an Bh- mother some­
times leads to tragic results*

The first child born of such parents (Bh* father and Bh- mother)
usually escapes harm, but b y the tine the second or third child is
developing there may be sufficient antibodies in the mother's blood
to cause the symptoms described above (erythroblastosis) to occur
in the inf ait if it happens to be Bh**

22$

H

2.

This disease (Rh disease) known as erythroblastosis foe tails, has
long been recognised, but the cause was not known before the dis­
covery of the Rh antigens*

113*

(As previously mentioned), the first child b o m to parents of this
Rh combination (Rh+ father and Rh- mother) usually escapes harm
and occasionally the second and third child may be unaffected*

llli.

There have also been eases in which no children (of Rfet fathers
and Rh- mothers) showed symptoms, however, surveys indicate that
about one out of twenty-eight babies b o m to such parents show
symptoms of this disease (Rh disease)*

115*

Of those (babies) showing these symptoms (of Rh disease) same re­
cover without medical attention, others, more severely affected,
may recover with medical treatment, and a few are stillborn or live
for only a short time*

116.

With increasing knowledge of the factors involved, physicians are
constantly developing better techniques for the treatment of this
disease (erythroblastosis)*

117*

Use question whether mental ability is inherited has frequently
been asked*

118*

It is well recognised that the human population varies In intelli­
gence from the Idiot, who never reaches a mental age. high enough
to care for himself, to the genius, who presents the world with
great accomplishments In literature, music, and science*

121*

(On the other hand), an individual who has a low mental capacity
could never become a genius even if ha were exposed to a society
of the highest academic level*

12li*

Tests have been compiled by psycholegists to measure Intelligence*

12$.

These tests measure intelligence in terms of mental age*

128*

The persons considered mentally deficient or feeble-minded are
classified as Idiots, imbeciles, or morons*

3-31*

Idiots are absolutely helpless when it comes to feeding and caring
for themselves*

132*

One type (of idiot) Is the microcephalic, or pinhead, in which the
bones of the skull close very early In the life of the Individual earlier than in normally developing Individuals*

13l*«

Another type of Idiot Is the cretin*

226

135.

.

Cretinism is the result of insufficient thyroid hormone during early
development.

136

One hypothesis as to the cause of idiocy is purely environmental,
attributing the idiocy to faulty prenatal environment or birth
injuries.

137.

Another hypothesis as to the cause of idiocy points to heredity and
requires the presence or absence of certain genes which, when expressed, produce the condition.

138.

Ihe third, and probably the least dogmatic hypothesis as to the
cause of idiocy, includes both environment and heredity as con­
tributing interacting factors.

139.

An example of a type of feeble-mindedness which definitely is heredi­
tary is phenylketonuria.

*. In normal

11 0

individuals, phenylpyrivic acid, which is one of the pro­
ducts of metabolism, is oxidised by an ensyme.

Hil.

In phenylpyruvic idiots, the ensyme (responsible for the oxidation
of phenylpyruvic a d d ) is not present and phenylpyruvic a d d is not
oxidised and is excreted in the urine.

li*2.

The excess of phenylpyruvic acid in the body damages the nervous
system, thus causing idiocy.

11*3.

Phenylketonuria is due to a recessive gene which results in the
absence of the ensyme necessary for oxidation of phenylpyruvic acid.

11*5.

Some feeble-mindedness, higher than Idiocy, is also thought to be
due to heredity.

11*
6. Family histories Indicate that this type of mental deficiency
(feeble-mindedness higher than idiocy) occurs much more frequently
in some families than in others.

11*7.

The study of twins supports the hypothesis that heredity is the
cause of certain kinds of mental slowness.

11*9.

It is known that superior intelligence runs in families.

150.

It is claimed b y some that superior intelligence is due to an en­
vironment which encourages the development.

151.

If environment is the sole cause (of superior Intelligence) one
would expect that all children reared in favorable surroundings
would develop into superior people. This, however, is not the
case.

227

15>2*

Dullards do appear In favorable environments, though not so fre­
quently as in other families*

15U*

Studies made of children reared in orphanages where, presumably,
the environment is fairly constant for all individuals, shew that
just as much variability exist among these orphans as in children
raised in their own homes*

l£6.

It has been found that there is a closer correlation between true
parent and true child than between foster parent and foster child*

158*

Insanity is a derangement of the normal mind*

159*

A person of normal or superior intelligence may become insane*

160*

There are some twenty types of insanity, several of which are con­
sidered hereditary*

161*

Huntington's chorea is inherited as an autosomal dominant*

162.

Because Huntington's chorea frequently appears late in adult life,
its presence is frequently unsuspected until after the individual
has married and reproduced*

163*

Because Huntington's chorea does appear late in life after the nosv
raal reproductive period its control is difficult*

l6U»

Huntington's chorea is a rare disease*

165*

Hospital records show no more than 100 to 200 cases of Huntington's
chorea per year in the United States*
j

166.

The victims of Huntington's chorea exhibit irregular and spasmodic
movements of the face and arms* Gradually other voluntary muscles
are Involved and the mental functions either slowly degenerate or
the individual becomes violently insane*

167*

^here is no known cure for Huntington's chorea*

168*

Schizophrenia (Dementia Praecox) is characterised b y melancholia,
emotionalism, and delusions of persecution*

169.

Some geneticist claim that schizophrenia is hereditary and they use
as a basis for their claim the fact that the frequency of the disease
among relatives of affected persons is much greater than in the
general population*

170*

A study of twins shows that when one member of a pair of fraternal
twins develops the disease, the other develops it in less than onmfourth of the cases (schizophrenia)*

M

228

171*

In identical twine when one member of a pair develops schizophrenia,
both twine develop the disease in nearly every case*

172*

The environmentalist say that there is greater frequency (of
schizophrenia) among relatives of affected individuals because
of coimon environment, common problems and cannon frustrations*

173*

It seems reasonable to assume that mental defects are determined,
in part, by heredity, since mental illnesses have their basis in
the nervous system and the functioning of the endocrine glands*

17U*

Geneticist who have worked on the assumption that schizophrenia is
inherited have postulated that it is transmitted as a recessive
trait*

175*

It is further postulated that individuals possessing genes for
schizophrenia will not exhibit symptoms for it unless they are
faced with certain types of problems and frustrations*

176*

If individuals possessing the genes for schizophrenia should never
be placed in an environment where certain types of problems and
frustrations exist, it is believed they may not develop the disease*

177*

Epileptics suffer convulsions with loss of consciousness*

178*

Recent work indicates that epilepsy is due to a dominant gene with
variable expressivity*

179*

By means of the electroenocephalograph (an instrument used to re­
cord the electrical pulsations of the brain) it has been found that
all epileptics have an abnormal type of brain wave (cerebral diarfaythmia) and that at least one of the parents will also exhibit
this type of brain wave even though he may not be subject to the
seizures*

l8o*

It is assumed that the abnormal brain wave is the consistently ex­
pressed inherited condition (due to the genes responsible for
epilepsy), and for some reason, possibly environmental influences,
people displaying this abnormality may or may not exhibit epileptic
convulsions*

182*

There is little doubt from the standpoint of the common good of
society that measures should be taken to control the spread of
known hereditary defects throughout the population*

I81j.*

Biologist have also pointed to the improvement of the
through selective breeding*

185*

Whether the measures of negative or positive eugenics will be
applied is dependent upon the attainment of a degree of social
consciousness which, at present, seems Utopian*

stock

229

187*

Through a program of general education society can come
stand the facte placed at its disposal by science*

to under­

188*

The development of a willingness on the part of society to use
facts for its own good will have to wait upon an advance in our
social evolution*
MEAN SCORE 3*51 - h*50

Items number 126, 127, 129, 130 and 133*
Appendix II*

Content may be obtained from

AREA VIII
Interrelationships:

Unit 1, The organism and Its Environment

The Specific Objectives
1* To understand the nature of the environment of living things*
2* To understand that adjustment of organisms to an ever changing
environment is essential if the organism or species is to sur­
vive*
3* To recognize that a knowledge of ecological principles in­
creases one's understanding of human societies*
Principles
1* The animals and plants living in the same habitat constitute s
community of interrelated and interdependent members* The plant
life of the community is the primary determinant of the char­
acter^ of the community which because of its characteristics may
be considered a superorganism*
2* The feeding relationships between the organisms of the commun­
ity constitute the center of activity within the comnunity*
Other basic pursuits by the organisms of the c o m m n i t y are
those involved in obtaining shelter and protection from the
biotic and physical elements of the environment, mating, and
caring for the young of the species*
3* The world of nature is in a state of continual change* O r ­
ganisms comprising a given community are continually altering
the soil and water conditions of the habitat so that those
organisms originally inhabiting the area must adapt themselves
to the changes, migrate, or perish* Thus one community paves
the w ay along the environmental path for another community in
a dynamic progression called ecological succession*

230

U*

5*

The carbon cycle and the more complicated nitrogen cycle ex­
emplify the complexity of the interrelationships among living
things and their physical environment* In each instance there
is a cyclic chain of events from the inorganic to the organic
and back to the inorganic elements of the environment*
Social groupings among individuals of the same species and
associations between individuals of different species are
adaptive responses which often increase the chances for sur­
vival of the organisms involved*

The Assignment
Biological Science Lecture Syllabus, pp* 139-175*
Principle I - The animals and plants living in the same habitat consti­
tute a community of interrelated and interdependent members*
The plant life of the community is the primary determinant
of the character of the community which because of its
characteristics may be considered a superorganism*

MEAN SCORE *5 - 1*50
1*

No animal or plant lives a completely independent life*

2*

All organisms are in constant interaction with their environment
and continually respond to environmental factors in order to main­
tain themselves*

U*

The basic relation between organism and environment is the same for
both plants and animals*

5*

The environment of a given organism includes the sum total of the
conditions or factors to which it is exposed*

20*

The animal life of the biome is dependent largely upon the plant
life in the area*

MEAN SCORE 1*51 - 2.00
3*

The responses of animals are often more immediate and noticeable
than those of plants because of the higher degree of organization
in animal forms*

10*

Plants and animals are associated in natural units over the earth*

15*

The biome is not a static unit, but extremely dynamic*

231

16*

The growth and development of the blame includes all of the changes
bare or denuded areas pass through in arriving at a condition of
relative stability called the climax stage,

19,

The vegetation present (in a biome type or natural unit) is dependent
upon climatic and other factors of the environment*

21* Man, in turn, is dependent upon both plant and animal raw materials
obtained from these natural life areas in order to live and build
his industries and institutions*
23* The habitat factors of climate and soil are important determinants
of the distribution of plant and animal life*
2U*

The interaction of living organisms within the biome constitutes the
biotic environment of the individual organism or the population*

2^.

All of the organisms living within the -unit (biome) are striving to
keep alive and reproduce their kind, the competition for food;
shelter, space and mates results in a web of life exceedingly ooav>
plex in its nature*
MEAN SCORE 2*01 - 2*50

6*

The place or niche that an organism occupies in nature is called
its habitat*

7*

The term (habitat), however, includes only the physical factors la
the environment of organisms and not the organisms themselves*

8*

(In other words) the habitat is the physical framework that supports
in one way or another the living organisms in a given comaunlty*

11*

These (natural) units are called communities or, more specifically,,
blames, and each contains many kinds of habitats*

12*

To the biologist the biome is more than the sum of its parts*

13*

In a certain sense the bicme may be regarded as a kind of super*
organism*

1U*

The biome concept is an operational concept in that it has proved
useful in furthering our understanding of the interrelationships
among living things*

17*

The earth can be divided into eight biome types. These are (1)
tundra and ice, (2) coniferous forest, (3) temperate forest, (U)
grassland. (5) desert, (6) tropical forest, (7) temperate ralm
forest, (8) the ocean*

232

18.

Each of the major natural units (biome types) produces characteristic
vegetation#
MEAN SCORE 2#gl - 3*50

9# (For example) the habitat of an oyster population includes such
physical factors as the type of bottom, the chemical,conditions of
the sea water, the pressure, and light and temperature conditions
prevailing in the area, but does not include the interactions be­
tween the oyster and its prey, parasites or predators#
22#

The major vegetation areas on the earth's horizontal surface are al­
so evident in the vertical plane, as on high mountains#

Principle II - The feeding relationships between the organisms of the
community constitute the (center of activity within the
community# Other basic pursuits by the organisms of the
community are those involved in obtaining shelter and
protection from the biotic and physical elements of the
environment, mating, and caring for the young of the
species#
MEAN SCOHE #5 - l.gO
1#

One of the most important integrating factors in the biotic enviroxw
ment is the food chain#

2#

The degree of interdependence of living organisms is evident in the
food relationships of the community#
MEAN SCOHE 1#51 - 2#00

3#

In a typical fresh—water pond the microscopic green plants or alga#
reproduce and grow in oountless numbers#

h#

The algae (in a fresh water pond) transform radiant energy inte
chemical energy of food by their photo synthetic activity and con­
sequently serve as the basic source of food for the community#

5#

Protozoans, microscopic crustaceans, and rr"*"11 insects feed upon
the algae (in a fresh water pond), and these animals, in turn, are
fed on by such larger animals as aquatic Insects and small fish#

233

6.

Large fish feed upon smaller fish and larga insects (in a pond) and
finally reptiles, birds, and mammals utilize the fish as food*

7.

In a food chain such as that in a fresb-water pond, millions of
algae are required to support thousands of microscopic animals,
called key industry forms, which feed upon them*

8*

The thousands of animals, which hare transformed plant protoplasm
into
protoplasm, sustain hundreds of fish, which in t u n
support the relatively few fish-eating vertebrates®

9.

A food pyramid is established for every food chain*

10.

The food pyramid serves to present the quantitative aspect of the
food web in a community®

11.

Food pyramids are the result of two tendencies: (1) that smaller
animals have a higher capacity to reproduce themselves than do the
higher animals, (2) that the smaller animals usually are the prey
for the larger animals®

12*

Included as factors in the formation of food pyramids are such (fac­
tors) as the size of the food, the amount of food, the availability
of food, and the capacity an animal has to utilize the food®

18.

Studies of fluctuations in animal, populations, whether free living
or parasitic, demonstrate that a change in one link of a given food
chain will inevitably influence all the organisms involved in the
chain*

21*

What is true for the free-living forms is true for the parasites
they harbor* Food chains and parasitic life cycles are closely
intertwined®

MEJUf SCOBS 2*01 - 2*50
13*

Organisms expend energy to obtain food and nourishment®

111*

A very large animal occupying the apex of the (food) pyramid might
be able to maintain itself on aneba protoplasm, but the amount of
energy required to obtain sufficient numbers of aneba for this pur­
pose would be altogether out of proportion to the energy yield of
the food®

15®

Because of the relationship between energy required to obtain food
and the energy obtained from the food, animals usually feed upon
the next size group in the food pyramid, thus obtaining the elements
in the aneba protoplasm at third or f ourth hand®

23k

20*

Any factor or set of factors which renders the environment unsuit­
able for the rodents will seriously influence the carnivores which
prey upon then*
MEAN SCORE 2,$1 - 3»50

16*

Ihere are notable exceptions to this rule (that animals usually feed
on the next size group in the food pyramid) such as the Whalebone
whales and the Mississippi River paddlefish, which, despite their
size feed on microscopic animal, and-plant life*

17.

Man is the only organism which can feed on any size food*

19*

It is well known that in Canada the arctic fox fluctuates with the
leanings, the numbers of red foxes fluctuate with mice and rabbits,
the fisher varies with mice, rabbits and fish, and the lynx popula­
tions are correlated with the numbers of rabbits*

Principle III - The world of nature is in a state of continual change*
Organises comprising a given community are continually
altering the soil and water conditions of the habitat so
that those organisms originally inhabiting the area must
adapt themselves to the changes, migrate, or perish* Thus
one community paves the way along the environmental path
for another community in a synanlo progression called
ecological succession*
MEAN SCORE *5 - 1*50
1*

The tendency to change is characteristic of life, whether at the
cellular. Individual organism, population or community level*

2*

The changes which take place at the coaummity level tend to put the
plant life in better adjustment with the soil, water, light and
biological conditions in the area*

3*

Once the adjustment (between the plant life and other conditions In
the area) is affected, a relatively stable condition known as the
climax stage is reached*
■9

5*

The primary causes of ecological succession are (1) the reactions
upon the habitat by the organists living there, and (2) modifica­
tions of the habitat by such physical forces as silting, obemioal
changes in the soil caused by leaching of salts from the soil,
drainage of swamps, fire, cultivation and many others*

23$

6*

(In all instances) the biological and physical forces at work cause
a change in the plant life of the area* and changes in the plant
life cause changes in the nature of the animal life* In this way
the character of the community changes and one type of community
pares the way along the environmental path for each succeeding com­
munity until the relatively stable climax community is reached*
MEAN SCOfffi: 1*51 - 2*00

]**

The series of changes leading to the climax stage is called ecolog­
ical succession*

15*

Ecological succession may also have its beginning in a lake, pond
or stream instead of barren rock*

19*

Succession also occurs within a community*

23*

A knowledge of the natural trends in ecological succession is of
importance to man in his efforts to conserve soil, improve gracing
conditions for his cattle, increase the productivity of his forest
lands, and conserve his wildlife*
MEAN SCORE 2.01 - 2*50

7*

A typical example of the interaction (leading to the climax community)
is the transition of a given area from barren rock to the climax
vegetation of the area*

8*

The first organisms to invade a barren rock substrate are terrestrial
algae, bacteria, lichens and mosses*

9m

through the continued action of climatic forces together with the
biological action of terrestrial algae, bacteria, lichens and mosses,
soil is formed from barren rock substrate*

10*

When soil is formed In an area the environment is prepared for an
invasion by various herbs and weeds*

12*

Eventually, when sufficiently deep soil has been formed, shrubs and
trees may Invade the area, leading to dominant forms of vegetation
which make it difficult for new species to gain a foothold*

13*

Frequently the climax type of vegetation for a given area is not
reached because it is arrested at some stage in the succession by
such human activities as repeated burning or the constant use of an
area for grazing purposes*

236

lii.

Arrested development (toward the climax stage) Is temporary, how­
ever, for once the human influence Is withdrawn, the natural process
of change continues toward the climax type of vegetation*

16.

When ecological succession begins in a lake, pond or stream the in­
vasion of shore plants and the gradual deposition of silt reduce the
area of open water and eventually a bog or swamp results*

17.

The drying up of a bog or swamp, and subsequent changes in the soil
conditions create an environment suitable for land plants*

18*

Over a period of time (beginning with a lake, pond or stream) a
climax community with its characteristic animal life will develop*

22*

In the type of succession occurring within a culture of protozoa,
the accumulation of metabolic wastes together with the exhaustion
of food are important determining factors*

2lu

Human efforts to conserve the replaceable natural resources without
consideration of the natural trends in ecological succession are
doomed to failure*
MEAN SCORE 2.£L - 3*50

11*

Herbs and weeds are characterised by possessing light seeds which
can very easily be transported by the wind*

20*

An example of succession within a community is the succession in a
culture jar of protozoa*

21*

In a new culture of protosoa the clear culture medium becomes cloudy
because of the rapid accumulation of bacteria* Changing environmen­
tal conditione in the culture jar then permit the development of
various types of protosoa, eventually leading to a culture of the
bell-shaped, stalked protosoa called Vorticella*

Principle I? - The carbon cycle and the more complicated nitrogen cycle
exemplify the complexity of the interrelationships among
living things and their physical environment* In each
instance there is a cyclic chain of events from the in­
organic to the organic and back to the inorganic elements
of the environment*

MEAM SCORE *S - 1.50

3#

soil is essential to life because it is the source of the chemical
elements and compounds necessary for the formation and maintenance
of protoplasm*

32*

Because amino acids cannot be synthesised without nitrogen and pro­
teins cannot be made without amino a d d s * the life of all organisms
is dependent on the nitrogen of the atmosphere*

33*

Despite the abundance of nitrogen in the air, green plants which
manufacture the
acids cannot obtain the nitrogen directly
from this overhead supply*

3ii*

Green plants must get nitrogen from, the nitrogen compounds in the
soil In the form of soluble salts and ammonia*

36*

The interchange of nitrogen between the atmosphere and the soil is
cyclic in nature*

37*

The cyclic interchange of nitrogen between the atmosphere and the
soil is one of the most, fundamental interrelations hips between liv­
ing matter and the inanimate environment*

ill*

Animals eat (the) plants or saprophytic plants attack then and
digest the proteins to amino acids, which are then resynthesised
into the proteins of the devouring organisms*

ii6*

Basically there are four processes Involved in the nitrogen cycles
(1) the process of decomposition involving the organisms of decay,
(2) the process of nitrification in which a— ionium compounds are
changed into nitrite and nitrate compounds, (3) the process of
denitrlfication In which certain kinds of bacteria operating under
certain soil conditions change nitrogen compounds of the soil into
free atmospheric nitrogen* and (1») the nitrogen-fixing process In­
volving the nitrogen-fixing bacteria which either live in a sym­
biotic relationship with leguminous plants or are free-living
convert atmospheric nitrogen into the usable nitrate form*

U7*

The element carbon is also constantly being withdrawn from the »nvironment to became a part of the organic makeup of living things*

1*8.

The source of the carbon used by living things is the carbon
of the atmosphere and water*-

1*9*

The atmospheric supply of carbon dioxide is replenished through the
respiratory activities of animals and plants, especially bacteria;
through the combustion of animal and plant residues such as wood,

238

coal, petroleum, gas and the dead remains of organisms; and through
volcanic eruption which bring into the atmosphere carbon dioxide
trapped in the earth's crust in the geologio past*
£0.

Carbon dioxide diffuses into green plants and is used in the manu­
facture of simple sugars*

51*

lhe simple sugars (manufactured b y the plant) may be oxidised im­
mediately by the plant for energy, in which case the carbon dioxide
is released
to the atmosphere, or used again in photosynthesis*

56*

If the plant dies, bacteria and other organisms digest and decompose
the plant compounds and eventually release the carbon as carbon
dioxide*
MEAN SCORE 1*51 - 2,00

1*

The physical environment of animals and plants consists of three
media - soil, atmosphere and water*

26*

The atmosphere is (one of) the basic media in which organisms
and from which they obtain their requirements#

live

28*

The atmosphere consist mainly of nitrogen, oxygen and carbondioxide*

30*

Theamino acids cannot be synthesised without nitrogen*

35*

Nitrogen is constantly being lost from the soil to the atmosphere
and is being constantly returned from the atmosphere to the soil*

38*

Certain bacteria known as nitrogen-fixing bacteria can utilise
atmospheric nitrogen to manufacture nitrates (NQ^)*

39.

Nitrogen-fixing bacteria may be living either in the nodules of the
roots of leguminous plants, such as peas, clover, alfalfa and beans*
or as free organisms in the soil*

UO*

The nitrates produced by nltrogexw-fixixig bacteria are used by plants
in the synthesis of amino acids and plant proteins*
i

i*2*

In animals some proteins are used to produce carbohydrates, with the
result that nitrogen is released and excreted as urea*

U3*

Urea and eventually the dead animal boctyr are decomposed by putrefac­
tive bacteria which change the nitrogen compounds to
(NH3)*

Ul**

Ammonia is returned to the soil (through the action of putrefactive
bacteria) and is acted upon by a group of bacteria which chaxwe
m naonia into nitrites (ND2 )*

239

U$m

A third group of bacteria, the nitrate bacteria, change the nitrites
into nitrates (NO^)•

52.

The simple sugars (manufactured by the plant) nay become a part of
complex carbohydrate molecules to be used as a part of the plant
structure*

53.

The simple sugars (manufactured by the plant) nuay be synthesised
into proteins or fate*

5U.

If the carbon becomes a part of the plant as complex carbohydrate,
protein or fat, it remains in the plant until it Is digested and
used by the plant or until the plant Is eaten by an animal or dies*

55*

If the plant is consumed by an animal, it is digested and the carbon
may become a part of the animal body as animal carbohydrate, fat or
protein or it may be used for energy and carbon dioxide may be given
off as a by-product*

57.

The carbon in animals is also released to the atmosphere as carbon
dioxide when the animal dies and decomposes*

59.

By one of the three processes, fermentation, putrefaction, or decay,
the carbon becomes a part of the microorganisms before it is released
to the atmosphere as caxbon dioxide*

72.

Oxygen, like nitrogen and carbon, is constantly being passed back
and forth between organisms and the atmosphere*

73.

Both plants and anim als remove oxygen from the atmosphere and use it
in respiration.

74.

The green plants return oaqrgen to the atmosphere thxugh the photosynthetic process*

102*

Light is essential to the process of photosynthesis and consequently
is basic to the food supply of ail living things*

103*

The photosynthetic process carried on by chlorophyll bearing plants
transforms the radiant energy of the sun into chemical energy, thus
bridging the energy gap between the physical and biological worlds*
MEAN SCORE 2.01 - 2.50

2.

Operating within these media (soil, atmosphere, water) are the
physical factors of light, heat, pressure, gravity and rlinmln >1
concentrations*

2U0

1*.

Living natter contains a minimum of ten essential elements*

5*

The essential elements (In protoplasm) are carbon, hydrogen, oxygen,
phosphorus, potassium, iodine, nitrogen, sulfur, calcium, iron and
magnesium*

8*

Soil is a mixture of fragmented rocks and minerals, organic matter,
water and air in varying proportions*

9m

Soil develops under the influence of climate and living organisms*

U*

The extent of weathering in any area depends upon the climate*

12*

Dead organisms contribute the organic matter of their bodies when
they decompose*

13*

Living organisms also contribute organic matter (to the soil) in
the form of waste products*

lh*

Some living organisms, such as earthworms which live in the soil,
improve it by burrowing through it, feeding on it, and mixing the
organic matter and minerals*

16*

The production of good soil requires long periods of time* It is
estimated that 300 to 1000 years are required to produce one inch
of productive soil by natural processes*

17*

Because it requires such long periods of time to produce soil the
importance of soil conservation becomes obvious*

18*

The chemical, physical, and biological factors operating within the
soil exert their primary effects on the root systems of plants*

19*

The texture of soil, its temperature, and its water, air and mineral
content must be optimum if plants are to attain their
growth and vigor*

20*

The oxygen content of air in the soil is especially significant be­
cause of its influence on the respiratory activity of plant roots*

23*

The lack or insufficient abundance of any one of them (certain
mineral substances) can limit the growth and development of the
plant*

2ii*

A biological principle based upon (one phase) of the relationship
or organisms to environmental factors is called the "Law of the
Minimal"* It states that the factor present in minigum concentra­
tion in the environment of an organism may limit the growth aad
distribution of that organism*

2bX

27*

The atmosphere is a gaseous envelop that surrounds the earth*

29*

Nitrogen makes up 79 per cent of the atmosphere by volume and is
an essential element in living organisms*

31*

Proteins cannot be made without amino acids*

58*

Decomposition of organic compounds by bacteria and other fungi is
known as either fermentation, putrefaction or decay*

60*

Fermentation is the breakdown of sugars by bacteria and yeast with
the production of alcohols and acids*

61*

The souring of nrnig is an example of fermentation* Milk contains
sugars which are changed through bacterial action to lactic acid*

63*

Certain of the products of fermentation are carbon dioxide and
water*
Putrefaction refers to the decomposition of protein molecules by
microorganisms*

6$.

Protein molecules (may be broken down by microorganisms) into sim­
pler compounds to produce amino acids and finally carbon dioxide*
ammonia, hydrogen sulfide, nitrates, and other simple compounds*

69*

Decay is similar to putrefaction in that protein compounds are de­
composed*

75*

Though oxygen is almost universally available* it is much more
abundant in the atmosphere than in water*

80*

Whether in a pond or at altitude* low oxygen concentrations are
frequently a limiting factor to the life activities of organisms*

91*

As a basic environmental medium, water has many outstanding charac­
teristics* It serves as a solvent, food, circulating
temperature regulator, and catalytic, hydrolytic, and ionizing
agent*

92*

Water is an essential constituent of protoplasm and constitutes
between UO and 90 per cent of its substance*

95*

An organism* s water requirements are often partially met by the
organism's ability to extract a supply of water through the
metabolism of organic foods*

96*

In most Instances (however) living things depend upon free water
to supply their needs*

21*2

97.

The activation of the elements borrowed from the earth's crust and
atmosphere and organized into living things is affected by the
energy from the sun.

98.

Organisms derive their energy from their surroundings and also give
it up to their surroundings.

99.

The available radiant energy varies greatly on different parts of
the earth and also exhibits annual and daily cyclic fluctuations.

139.

Temperature affects the distribution of plants and animals on the
earth.

159.

(Gravity) influences the structural characteristics of organisms
as well as their behavior and physiological adjustment to the
environment.

171.

Organisms must be able to adjust themselves to their chemical en­
vironment.

172.

The chemical environment supplies the organism or tissue with
essential chemical foods.
MBAH SCORE 2.51 - 3.50

7.

Sodium and chlorine are essential to animal nutrition although not
Indispensable to plants.

.

10

The original rock of the earth is broken up in weathering by the
action of the wind, rain, heat and freezing.

15.

Tons of soil per acre are moved and enriched each year by earth­
worms.

.

21

.

Water-logged soil will eventually cause the death of plants because
water fills the air spaces in the soil, thus depriving the plant
of its oxygen supply.

22

Deficiencies in concentration of certain mineral salts in the soil
reduce the vigor of plants.

25.

An example of the "Law of the Minimum" is that there may be a super­
abundance of water and optimum conditions of light and dissolved
mineral salts, but the photosynthetic activity of any given plant
a*y fall below the energy requirements of the plant if the concen­
tration of carbon dioxide is too low. Should this persist over a
period of time the plant will die.
v.

2h3

62.

Tbs sour taste of <H.ll pickles is also the result of fermentation.

66.

Some of the intermediate products of putrefaction have unpleasant
odors*

67.

The microorganisms that cause putrefaction are anaerobes*

68.

Anerobes do not require free oxygen for respiration, but obtain
their oxygen from the compounds they decompose.

70.

Decay differs from putrefaction in that no unpleasant odors are
produced.

71.

The process of decay is carried on by aerobic micreorganisms that
must have free atmospheric oxygen for respiration*

76.

Many fresh water lakes are deficient in oxygen at the lower levels
during the summer months.

77.

Pollution frequently causes a depletion of dissolved oxygen in
lakes and streams.

78.

Atmospheric oxygen decreases in concentration with increase in
altitude.

79.

Breathing air at high altitudes results in oxygen starvation or
anoxia*

81.

Water covers about 72 per cent of the earth*s surface*

83.

Water evaporates from oceans, lakes and streams, land surfaces and
living things and is transferred as water vapor to all parts of tbs
world*

8U.

The water vapor in the atmosphere ultimately precipitates as rain,
fog, dew, snow, or hail and provides regions far removed from the
oceans with water.

85.

Bie cycle of water from earth's surface to atmosphere and back is
called the hydrologic cycle*

86.

The hydrologic cycle has undoubtedly continued with little change
throughout the geologic past until the present time.

87.

It is estimated that about 6,500 cubic miles of water run off the
land anually by way of streams*

88.

Annually, the run off water carries with it soma five trillion tons
of dissolved and suspended matter, all derived from the soil and
the earth* s crust.

4

2hh

89#

The increasing sal tineas of the aea is an evidence of the effective­
ness of the erosion process*

90*

Han's present and future welfare demands an effective control of
the destructive action of water*

93#

Unless animals and plants can adapt themselves to the water condi­
tions of their surroundings, they must either migrate to more con­
genial conditions or perish*

9b*

The water content of an organism frequently determines its ability
to withstand unfavorable environmental conditions*

100*

Solar radiation penetrates the earth's atmosphere quite readily,
but water absorbs certain of the wave lengths*

101*

These facts (concerning energy) are of significance with relation
to the distribution and activities of animals and plants*

10b*

As an envizomental factor,- light must be considered in terms of
its quality and intensity*

105*

The quality of light refers to its wave length*

106*

Color of light is a function of its wave length*

107*

Light intensity refers to the quantitative aspects of light*

108*

The environmental effects of light quality and light intensity are
well exemplified by the requirements of the photosynthetic process*

109*

Chlorophyll is most rapidly decomposed in the orange—red region of
the vlsable spectrum*

110*

It is also true that more light is absorbed by chlorophyll in the
orange-red region of the vlsable spectrum than in any other*

111*

The optimum quality of light for photosynthesis (consequently) is
light of the orange-red color*

112*

If the light intensity is too great, light of these wave lengths
(orange-red) becomes a limiting factor in photosynthesis*

113*

Plants need a definite number of energy units of light for their
growth and maturation*

Ulu

Generally, a plant functions more efficiently when the light is dis­
tributed over a longer period of- time at a lower intensity than
whan the opposite conditions prevail*

2U5

115*

Animals, almost without exception, can lire independently of light*

116*

Some animals such as the cave dwellers, deep-sea fishes, and in—
testinal parasites normally live In environments lacking light*

117*

Light does influence the activities and behavior of the majority
of animals*

11?*

The color changes in animals in response to the incident of light
are responses of the pigment—containing cells in the animal1s in­
tegument and are often adaptive in nature*

120*

In some fishes, as in some birds and m ammals, the sexual cycle
appears to be determined largely by the intensity of light*

122*

Earthworms generally move away from the source of light*

123*

Moths and many other Insects move toward a given light source*

12iu

Plant stems are definitely positive in their reaction to light*

125*

Plant roots are negatively phototropic*

128*

Animals and plants are extremely sensitive to sudden changes in
teaperature and are frequently killed at temperatures only a few
degrees above those d; Which they are accustomed to live*

129*

The death of organisms because of heat is best explained at present
by the fact that the proteins of the living cells become coagulated
in the same way that egg albumin coagulates when heated*

130*

The water content of organisms seams to be an important factor (in
resistance to heat), susceptibility to heat increases as water con­
tent increases*

131*

Animals and plants also nay be killed by cold*

132*

Water content is an important factor (in resistance to cold) sue.ceptibility to cold increases as water content increases*

13b* The rate at which biological reactions occur depends very definitely
upon the surrounding temperature*
135*

According to a physical law, the velocity of chemical reactions *Tt—
creases two or three times with each rise of 10°C* in temperature*
Metabolic processes conform to this law in a general way*

136*

(A more exact generalization is that) metabolic reaction* are con­
trolled by the slowest reaction in a metabolic aystam and that these
systems have critical temperatures*

2h6

137.

Enzymes are active within a narrow temperature range.

133.

Cold blooded animals do not have temperature-regulator mechanisms
and consequently their metabolic processes are more subject to
temperature fluctuations than those of warm blooded animals*

l/*0. Temperature influences the mechanical and chemical changes which
occur In soil and thus it Influences the nature of the plant cover
of.the region*
ill.

She distribution of herbivorous animals is correlated with the
distribution of plants and the distribution of carnivorous and
omnivorous animals is associated with the distribution of their
prey.

Ili2*

All living things are subject to mechanical pressure in the environ**
ment.

Iii3* Aquatic forms must withstand the pressure of the water which lies
above them.
lUlu

Terrestrial forms are adapted to the atmospheric pressure.

1146*

Chi land, the atmospheric pressure decreases with an increase In
altitude.

150*

The oxygen pressure at altitude decreases proportionately to the
decrease in total atmospheric pressure.

157* As in the case of other physical factors of the environment, living
things In general are adapted to a relatively narrow range of
pressures.
158* All living things

respond to the force of gravity.

162*

Another example of the influence of this factor is evident in
adaptations which occur in the skeleton of birds.

the

16/i.

As far as terrestrial forms are concerned, the factor of gravity
definitely limits the maximum size that an animal can attain.

165*

The behavoral and physiological adjustments of organisms to the
factor of gravity are quite evident in living things.

166. Acting in conjunction with plant hozmones, the factor of gravity
causes the roots of plants to grow downward and the stems of plants
to grow upward.
173* The chemical environment produces conditions of osmotic pressure
and acidity or alkalinity (hydrogen-ion concentration) which must
be optimum if the living matter is to function normally or at all.

21*7

17h.

Bed blood corpuscles of a frog, when placed in mammalian physiolog­
ical salt solution, will loose water and shrink*

175*

Plants, if over-fertilised, will die as a consequence of the failure
of their roots to adjust to the increased salt concentration of the
soil water adjacent to the plant*

176*

The adaptations of organises and tissues to chemicals can also be
extremely specific*

178*

Magnesium is absolutely lndispensible to the formation of the
chlorophyll molecule*

179*

The degree of acidity or alkalinity of the chemical environment is
of great importance*

180.

Adjustment of the hydrogen-ion concentration beyond an optimum
range is a common method of inhibiting bacterial growth*

181.

In human reproduction the degree of acidity of the female reproduc­
tive tract is a common cause of sterility because the male repro­
ductive elements are adapted to a relatively narrow range of
hydrogenlon concentration, and if the female tract is too acid the
spematosoa are killed*

182*

When living tissues or organisms cannot adjust themselves to their
chemical environment they die* This is the basis of chemotherapy
in the field of medical science*

183*

Antibiotic substances such as penicillin or streptomycin create an
unfavorable chemical environment for certain types of bacteria and
inhibit the growth of the bacteria thus enabling protective mech­
anisms of the body to exert their influence*

181** Metallic compounds such as mecurlo chloride and iodine cause the
death of the bacteria in a short time*
185*

If the chemical concentrations are not too unfavorable, organisms
can adapt themselves to changes in their chemical environment*

186*

Plants of the desert or seashore adapt themselves to increasing
concentrations of salts in their environment*

187*

Bacteria can adapt themselves to sulfonamide concentrations to the
extent that they become resistant to the chemical*

188*

Homan beings living at high altitudes, such as the plateaus of
Tibet and Peru, are adapted to the low oxygen concentrations pre­
vailing at those altitudes*

2he

189.

The adjustment of living things to their chemical environment illus­
trates strikingly that adaptability is a fundamental characteristic
of living matter*
MEAN SCOHB 3.SI - U.50

Items uiufeer 6, 82, 11A, 121, 126, 127, 133,
1U7, 11*8, 1U9, l5l,
152, 153, 15U, 155, 156, 160, 161, 163, 167, 168, 169, 170, and 177*
Content may be obtained from Appendix II*
Principle V - Social groupings among individuals of the same species and
associations between individuals of different species are
adaptive responses which often Increase the chances of
survival for the organisms involved*
MEAN SCORE *5 - 1«5P
2*

Associations of animals vary in their degree of organisation*
MEIN SCORE 1.51 - 2,00

1*

In general animals live together* Birds form flocks while fishes
farm schools* Mosquitoes s w a m and wolves travel in packs and hunt
the herds of deer* Bees, wasps and ants build their own horns,
where each individual has a specific function to perform*

3*

Some associations of animals are completely lacking in any degree
of integration and, in fact, are associated only*

7*

Associations or aggregations of animals are caused toy forces or
factors that are more social in nature*

8* Such aggregations as bird flocks, schools of fish, "dancing midges”,
and herds of deer are caused toy reactions to each other*
10* One aspect of aggregations (with a social basis) may be sexual and
result in the collecting together of two or more individuals during
the breeding season*
12* In some (animal ) forms the association is distinctly a social
phenomenon carried to a high degree of specialisation*

2h9

l£#

Human beings live together in an intricate and complex interdepen­
dence* The human from birth to death is a part of a group* His
distinctly human characteristics are the result of group living,
and the group goes on after the individual is dead*

16*

Group or social living is a common biological phenomenon*

17*

Group or social living varies from loose, temporazy, and accidental
associations to highly integrated and permanent interrelationships*

26*

The social characteristics that groups have in common involve (1)
the holding of territory, (2) doaiination-subardination, and (3)
leadsrshlp-followship*

36*

Social hierarchies develop in groups of animals based on the second
characteristic of group living, domdnance-subordinatlon*

60*

In a community relationships exist between species which result in
(1) the toleration of one species by the other (2) the exploitation
of one species by the other, and (3) the unconscious cooperation of
two species which results in mutual benefit being derived from the
association*

63*

The exploitation of one species by another is called parasitism*

92*

The host also is specific in its tolerance of parasites*
same and rejects others*

95*

Animals and plants that are parasitic have evolved from freeliving
ancestors*

97*

During the evolutionary adaptation from free-living to a parasitic
■ode of life, the parasite changes, and the degree of chaise usually
is correlated with the length of time the organisms has been para­
sitic*

98*

Parasites that hare been parasitic for a short time. In general,
show few changes and those that have been parasitic for a long •“
show great changes*

99*

It accepts

tut

The changes that a parasite undergoes are usually In the direction
of greater dependence upon the host*

MEJLMf SCOHB 2*01 - 2*50
h*

An example of accidental association is organisms cast into long
drift lines along the sandy beaches of lakes* In such drift lines
one can find many organisms including insects, — ■
n bivalves,
aquatic smalls, and even fish*

250

6* The collection of insects about a light on a summer evening is an
example of animals reacting in the sane way to the sane kind of
environmental stimulus*

9.

Instead of responding to an impersonal external force (animals
which associate because of reactions to each other) collect as a
result of positive reaction to the presence of others like them­
selves•

11*

Sex, however, is not the only factor (involved in aggregations of a
social nature) because manor animals collect together in nonbreeding
seasons or continue their association long after reproduction Is
accomplished*

13*

For example, (of an association which is distinctly a social phe­
nomenon carried to a high degree of specialisation) hives of bees
with the reproductive queen, the males or drones and the sterile
females or workers constitute a permanent association that is
organised so that the group is an entity in itself* Certain In­
dividuals may die but the group persist*

Uu

Ants and termites also represent social organisation in a complex
form*

18*

(Apparently), living together offers some advantages over the con­
dition of living alone*

19*

The advantages of cooperative group effort in human society are
obvious*

20*

Many examples are available demonstrating that the combined, co­
operative action of many people can accomplish tasks that ars
impossible for a single individual*

21*

The advantage gained by the less organised and unconscious associa­
tions (such as fish in a school or birds in a flock) is survival*

22*

An example that illustrates the survival value of aggregations of
animals is as follows: A large group of fish can tolerate an amount
of poison in the water that would kill a very few* The reason is
that each one of the group absorbs a small portion of the poison
and reduces the total amount so that no one fish Is seriously
affected* If only a few fish were present, the amount absorbed by
eaoh one would be enough to k i n it*

23*

Another example of survival value of aggregations la the collection
of certain birds in close groups during oold weather* Collectively
they can withstand the low temperature, while individually they
would perish*
%

251

2b*

Social groups have certain characteristics in common*

25*

the characteristics which social groups hare in common are social
characteristics and are derived from the interaction between the
members of the group*

27*

The different types of Interactions in the group nay* occur in fairly
pure form* or they nay grade into each other* even in schools of
fish* to give eoaqpilcated organisational pattern*

28*

The concept of territory refers to an animal1a recognition and pro­
prietorship of a certain area* It includes homing or the defense of
a certain area* or both*

29*

Homing reactions occur when an animal returns to a specific area
after it has left it*

31*

The defense of a given area is characteristic of territoriality*

33*

Organisms that show a reaction to territory react negatively to in­
vaders of the s ame species. They prevent* by actual combat* or
threat of combat* any individual of the same kind from entering
the selected area*

37*

An example of dominance-subordination is the peck order in chickens*
A newly collected flock of chickens will* in a relatively short
space of tine* develop a social organisation based on the domination
of certain individuals over others* The social order is established
and maintained by the giving and receiving of pecks* or by reactions
to threats of pecking* From this the term peek order has come to
refer to established social hierarchy in chickens*

bl* W* 0* Allee has suamarlsed the qualities that make for high social
status in groups of vertebrates as follows: (1) the stronger In­
dividual usually wins la apir contacts* (2) mature animals usually
dominate those less mature* (3 ) larger animals usually hove a
higher social rank than their smaller associates* (U) the location
of the first meeting is often important* since many animals fight
best in or near their hone territory* (5 ) an animal surrounded by
members of its own group often wins over a stranger* (6) animals
with young tend to fight more fiercely than at other times* (7)
males usually dom inate females* (8) the amount of male hormone pre­
sent often determines the social dominance of either sex* (9) the
female eoneort of a dominant male tends to be accorded hi* social
status so long as she remains near him*
U2*

Hereditary differences are important In relation to dcnlnatlomsubordinatlon*

252

U 6» Leadership, another characteristic arising out of group living,
consists in giving guidance and directing others along a eartain
course or pattern of behavior*
itf* A leader nay be able to attract others to follow him, but sonatinas
force is necessary to control the foilewers or even to secure then*
ii8.

The position of leadership is held by the animal that initiates,
stabilises, or integrates behavior of the group*

5U*

Leadership nay or nay not be associated with social status*

59* In rhesus nonkeys there, is a complete linkage of doninanoe and
leadership* The strongly dominant and aggressive individual is
also the leader*
61*

The term syxbiosis is used by the biologist to include all types of
(such)
partnerships (which exist in a conaunlty)* »
•

62*

The toleration of one species by another is called connensalisn*

6km

The unconscious cooperation between species is called mutualism*

67*

The ccousnsal relationship nay be casual, (as in the ease of the
honey bee and the flowering plant) or it nay be obligatory as in
the case of the Yuocampth and the Tuoca plant*

71*

Mutualisn is found between species of animals, species of plants
or between aninals and plants*

7iu

Other exnqd.es of antually beneficial relationships are those exp­
iating between certain fbngi and algae resulting in the eonposite
plants called lichens | the relationship between the root-inhabiting
nitrogen-fixing bacteria and leguminous plants; and the relationship
between certain taraites and their intestinal protosoa*

75*

Karaites cannot live without the presence of the protosoa (in their
digestive tract) for the protosoa digest the wood (cellulose) eaten
by the termites*

76*

Parasites are organ! ass, either plant or anlnal, that live on or
within another organise and at the expanse of the other organise*

77* „The benefits derived by the parasite M y include food, shelter,
dispersal, and a means of completing the life history*
78*

The host is an organ!an that harbors a parasite*

79*

If the parasite is in an innature stage of growth, the host is
usually known as an Intermediate host*

253

80*

If the parasite is adult, the host that harbors it is known as the
final host*

81*

lbs habitat of the parasite is the host#

82*

The habitat provided by the host is comparable to the water and land
habitata of free-living forms, and parasites become adapted to It
just as free living organisms become adapted to their (habitats)#

83#

The parasitic habitat is essentially of tan types* One is ecto­
pe rasitic, in which the parasite lives on the outside of the host#
Tha second is endoparasitic, in which the parasite lives within
the host#

86* Most parasites can live only in a specific host or hosts#
87* Parasites become adjusted to a certain host environment and can
tolerate no other*

This condition is known as host specificily#

88*

(Furthermore) parasites usually are restricted to living in or on
only certain parts of the host* This is tissue specificity#

90#

Other viruses, such as those that cause chickenpox and smallpox,
attack the skin*

96#

Parasitism probably began as a result of a chance encounter of two
organisms in which one served as a vehicle for the transportation of
the other# This relationship probably persisted for sometime, duxw
lag which the future parasite came to depend upon the host for food
and perhaps other necessities, and as the degree of dependence grew
the degree of parasitism grew#

100#

Tha variations in the parasites may be simplifications of structure
or they may be complications#

10li# (Ulus) imoature or larval parasites live in intermediate host, of
which there may be one, two or three* The adult lives in the final
host# lb complete development of the parasite or to complete its
life history, it must pass from host to host#
106*

The total effect of parasitism on the host depends upon a ™«^i» of
factors. Including the virulency of the parasite, the nunber of
parasites, tha resistance of the host, and whether the parasite-host
association is temporary or permanent and of long duration or of
recent origin*

^ #

Virulence is the capacity of a parasite to produce abnormal
tions in a host by reproducing rapidly and producing highly
substances#

o

109. Parasites that ars highly virulent cause the severe diseases, while
those of less virulence cause mild illnesses only*
n 3r Resistance off the host to a specific parasite is great in sons cases
and very little In others.
U5>. When the parasite host relationship is off long duration and the
parasite and host have lived together for countless generations, a
wfwfri.T tolerance sonatinas develops.
116*

Under conditions off mutual tolerance between parasite andhost, the
host may not be injured sufficiently to cause death, but he (host)
nay suffer from a slight and continued impairment off health known
as a chronic disease.

117.

If the parasite-host relation is of recent origin in the evolutionary
sense, severe reactions may occur. Tha host is unable to inhibit the
action off the parasite sufficiently to protect Itself from harm, and
as a result severe disease and perhaps death of the host ensues.
HEJ lM

SCORE 2 . A - 3.50

$.

Associations of animals may be brought about because the animals
all react the sane way to the same kinds of environmental stimuli.

30.

Ihe (return) distance covered (in the homing reaction) may be only
a few feet as in certain mollusks, or it may be hundreds of miles,
as in homing pigeons and the golden plover.

32.

Birds defend their selected territory against invaders, as do many
fishes, lisards and mammals, Including man.

3iu

An exception to this (defense of territory against entrance by
organisms of the same kind) is mads to a mate or mates.

3$.

Organisms (that shew territoriality characteristics) react posi­
tively to the (selected) territory, seeking it
living in it,

38. When two chickens meet for the first time either there is a fight
or one gifes way without fighting* The successful bird in the
Initial encounter retains the right to peck the other bird at ary
subsequent encounter. This process continues throughout the flock,
each chicken engaging in battle or threat of battle until all fall
into a serial hierarchy with one having the right to peck all othar
chickens and not be peeked in return; with a second being peeked
only by number one while it pecks all other hens in the flock} with
a third submitting to numbers one and two but dominating all the re­
maining birds, and so on, down to tha last bird in the flock which
receives the pecks cf all and gives none in return.

255

39•

Other animals that show a domination-subordination type of social
organisation include fishes, lisards and mammals*

i*0.

Certain human social organisations are suspiciously similar te peck
order,

1*3*

Inbred strains of nice tend to differ both in aggresiTeness and in
fighting ability,

1*1** Defeat which results in lowered social status is often accompanied
by easily recognised ohanges in behavior*
1*5.

A defeated fish nay drop its challenging posture of tense bocy and
erect fins; the fish seens to hang limply in the water; it backs
away slowly and then turns and flees* Many animals, anong then
hens, nice and boys, not infrequently enit characteristic caries
when beaten* The head furnishings of defeated hens sonetlnes
blanch, while those of the victor remain flushed* Defeated nice
rear up in characteristic postures* Other signs of low social
rank include the avoidance of encounters with superiors; defeated
hens nove about quietly, often with head held low, or hide in out-*
of-the^way places or in protected niches,

1*9.

Leadership nay be held by either male or female, who nay be young,
nature or old*

50*

Leadership nay be held by one individual or a group of individuals,

51*

The leader nay lead in the physical sense of going before when the
group changes its location or activity* However, this is not al­
ways true,

52*

The anlnal moving in advance nay not be the real originator of the
movement,

53*

In some Clocks of birds the bird in advance in flight is simply
following along in front of the flock* Any change in direction
originates within the body of the flock,

55*

In flocks of hens leadership often rest in the aid-social ranks
rather than with the number-one hen in the peck order,

5b*

Da ants individual-to-individual dominance is unknown, yet leader­
ship exist,

57*

Among groups of manuals the socially dominant animal, is often the
leader,

58,

Among the red deer of Scotland tha males exert dominance, but the
real leadership is held by a female.

256

65*

Among the most interesting of the commensal relationships are those
involving species of insects and flowering plants*

66*

The collection of nectar and pollen by honey bees to supply food
for the baa colony is an example of a caanensal relationship* 2h
the pursuit of nectar and pollen the honey bees make possible crossfertilization in the plants*

68*

lbs only insect capable of pollinating the Yucca flower is tha
Yucca moth*

69*

Tha female moth* after collecting pollen from several stamens*
drills a hold through the ovary wall of the Yucca flower and leys
her eggs among the ovules of the flower* Development of the ovules
into seeds is insured by inserting the pollen grains into the canal
of the pistil*

70*

Only a few eggs are laid In any one flower thus insuring an ade­
quate food supply for the larvae without endangering the propagation
of the plant upon whose existence the survival of the Yucca moths
depends*

72*

A mutually beneficial relationship existing between an animal and a
plant is seen in the relationship between the green alga Chlorella
and the fresh-water Coelehterate hydra*

73*

The green alga lives within
the carbon dioxide released
photosynthesis* The hydra*
liberated in photosynthesis

8I4.

Examples of ectoparasltie organisms are lice* fleas* and ticks on
man*

85*

Examples of endoparasitio organisms are protozoan blood parasites
that cause malaria* tapeworms that live in the intestine* and
bacteria that live in the respiratory, tract*

89*

Tissue specificity is exemplified by the viruses which cause rabies
and poliomyelitis and affect the nervous system only*

91*

The parasite is not the only part of the host-parasite relationship
that shows specificity*

93*

A host that tolerates the presence of a parasite is said to be
susceptible*

9ii*

A host that does not tolerate a parasite is said to be immune*

'

101*

the body walls of the hydra and utilizes
by the animal to manufacture sugar by
on the other hand* uses the oxygen
in its own respiratory activity*

Complex life histories have developed in many parasitic species*

257

102*

Complex life histories in parasites is associated with differences
between young and adults*

103*

Whan the offspring are like the parents, as in the case of bacteria,
both can lire in the sane environment and the complex life histories
do not develop* However, when the offspring have one form and the
adults have another, they need different environments in which to
live and develop*

105*

The
pork tapeworm is an example of a parasite having a rela­
tively simple life history* The adult tapeworm lives and reproduces
within the Taiwan intestine, the fertilised eggs pass out of the in­
testine with the human excreta* Most of them die, but some are eaten
by pigs* Within the pigs they undergo certain growth changes and
migrate until they invade the pig's muscles* If man eats the pig's
muscle tissue in the fezm of insufficiently cooked pork, the young
tapeworm gains entrance into the human digestive tract, where it
develops into an adult*

lu8*

Parasites differ in their virulence*

110*

The number of parasites that invade a host has a decided effect on
the severity of the host's reaction*

111*

A few parasites can usually be tolerated by the host, but if the
numbers increase the host's resistance is usually overcome and the
damage may be great*

112*

The resistance of the host to the specific parasite determines
whether the parasite will became established*

llii*

Temporary associations of parasite and host, such as mosquito and
man, seldom do much damage, while more or less permanent associa­
tions such as tuberculosis-causing bacteria, hookworms and tapeworms
can cause great damage*
AHBA V I H
Interrelationships:

Unit 2, Populations and Conservation

Specific Objectives
1* To understand the relationship between a species' capacity to
reproduce its kind and the factors of the environment which
resist increase in population also*
2* To recognise the fact that Taiwan populations are subject to
tha sane biological forces as are the populations of other
organisms*

258

3*

To understand the significance of the conservation of natural
resources to human welfare*

Principles
1# The population size of a species Is a result of the interaction
between the theoretical capacity of that species to reproduce
Its kind (its biotic potential) and the environmental resis­
tance confronting the organises comprising the species*
2* The conservation of natural resources is a logical consequence
of nan's understanding of the interrelationships among living
things and between the living and non-living parts of the
environment*
The Assignment
Biological Science Lecture Syllabus, pp* 176-216.
Principle I - The population size of a species is a result of the inter­
action between the theoretical capacity of that species to
reproduce its kind (its biotic potential) and the environ­
mental resistance confronting the organisms comprising the
speoies*
MEAN SPORE .5 - 1.56

1.

The physical and biological factors In the environment can be thought
Of as constituting a resistance to the increase in numbers of living
things*

2.

Unless the Individual living organism is adopted or can consciously
adjust itself to unfavorable environmental conditions, it cannot
survive*

3.

This principle (that unless the Individual living organism is adapted
or can consciously adjust itself to unfavorable environmental con­
ditions, it cannot survive) applies with equal effectiveness to
populations of individuals*

U*

Since all living things possess a tremendous capacity to reproduce
their kind, the size of animal or plant populations fluctuates with
the degree of environmental resistance exerted*

5*

This basic concept of interrelationships In the natural world can
be expressed very simply by the equations

-

asgrsaMSL.

25>9

23,

In tals efforts to understand the population aspects of group biology,
the biologist is concerned basically with three factors* These
factors are (1) the birth rate, (2) the death rate, and (3) the dis­
persion within the population*
MEAM SCORE 1*51 - 2*00

9*

Biologist hypothesise that the failure or success of the human race
will depend upon the wisdom nan shows in controlling his reproduc­
tion quantitatively and qualitatively*

10*

In this respect (ability to apply control measures to his reproduc­
tion both qualitatively and quantitatively) man differs from other
living things, for he (nan) can apply creative intelligence to a
problem which other living things must leave to the action of nonconscious natural forces*

11*

A population can be conpared to a living organism in several respects*

12*

like an organism, a population has a life history, It grows in a
typical fashion, undergoes changes that may lead to a division of
labor among its members, ages and dies*

13*

Like an organism it is an integrated unit* It meets the forces of
the environment as a whole rather than as a loose assemblage of
parts*

16*

The basic similarity (between organises and populations) is espe­
cially evident when a population growth curve is compared to the
growth curve of an individual*

17*

Under ideal environmental conditions the growth of a population
follows the same pattern of development as does the growth of an
Individual*

18*

Growth is slow at first, gradually increasing in rate
mum is reached* Almost imperceptibly this rapid rate
gins to slow down and after a time the rate decreases
rapidly until at a later date there is no appreciable
the also of the population*

19*

When the growth of a population is plotted with either weight or
numbers against time, a typical S curve is secured like that for
the growth of an individual*

20*

A population is defined as a group of living individuals set in a
frame that is limited and defined in respect to time and space*

until a maxi­
of growth be­
more and mere
increase in

260

9J[f The birth rate, or population-increas# factor, takes into considera­
tion the theoretical reproductive capacity and the realised repro­
ductive performance of a species*
1*2*

One of the most significant elements in the biological envlrozseent
of living things is population density*

1*5#

Increased crowding of organisms in a population reduces the growth
rate and can even bring about a decline in the population*

1*6*

If there Is competition for food the fecundity of the females in
the population de caresses with an increase in population#

50*

A growing and vigorous population contains a great preponderance of
young organisms#
MEAM SCORE 2*01 - 2*50

8*

We need not, however, limit our example to bacteria* It has been
estimated for humans that if one husband and wife had six children
and each pair of children had six children, the entire world could
be populated in nineteen generations* ?ha fourth generation would
produce 162 individuals while the nineteenth would consist of
2,321*,522,931* individuals#

11**

(A population) has an heredity#

15*

The structure and composition (of a population) change with in­
creasing ag# even though at any one time it seems very stable*

21#

If more than one species is included in the group, the group is
spoken of as being a mixed population#

22*

Animal and plant communities are usually mixed populations#

26*

(for example), a population might have a theoretical reproductive
capacity of 20,000 offspring per year but a realised reproductive
performance of only 3,000 individuals for the same period of time*

27*

Statistics on human populations show that the range of reproductive
performance extends between an average
of approximately 50
birth per 1,000 population per year to an average mini m m of approxi­
mately 15 birth per 1,000 annually#

29*

Studies also reveal that in humans the rate and success of repro­
ductive performance in a population are determined b y the age of the
reproducing members#

261

31*

The death rata, or populatlon-decrease factor* interest the biolo­
gist fro* the standpoint of w h y organises die and why they die at a
certain age*

32*

It is a population principle that different phases of the life his­
tory of a population hare different and characteristic death rates*

33*

If the cause of death (of a population) can be ascribed to the
environment* it follows that a nore couplets knowledge of •the en­
vironment can lead to reductions in the death rate* if this la
desirable*

36*

Although the human population may be declining in certain areas on
earth* in general the human population is increasing in sise at a
relatively rapid rate*

1*0*

The dispersion factor is concerned with the emigrations and immigra­
tions which occur within a population*

ill*

If either (emigration or immigration) is excessive a condition of
depopulation or overpopulation can take place within an area*

U3*

(Population density) is defined as the number of organises per unit
apace they occupy*

UU* ~ (Population density) has been shown to affect the growth form of a
population*
17*

When the total environment is unsaturated* increased eudLgration
caused by crowding leads to survival in the population because the
organisms moving out find environmental niches still unexplored*

US*

When the total population is static* however* emigrations from one
place to another lead to death*

U9*

(Finally)* the age composition of a population reveals the "young­
ness* or ■hldtaess" of the population in terms of its life history*

51*

A stationary population has an intermediate number of young as oca*»
pared to did individuals*

52*

A declining population is characterised by a preponderance of old
organisms*

S3*

The social* economic* and political implications of these facts far
human populations are manifold*

262

MEAN SCQBE 2*SL - 3*50
t

6*

The idea of an o r g a n i s e theoretical capacity to reproduce can be
gained from the following example* It has been estimated that a
single bacterium 1/ 20,000 of an inch long and 1/ 30,000 of an inch :
thick, if allowed to reproduce to the limit of its capacity without
the restraining influence of its environment, could, in one day* s
tine, fill.a pipe one inch in diameter reaching from New York to
San Francisco*

7* Within twenty-four hours this reproductive spree (of a single
baeterima) would result in fbur aextlllicn bacteria*

25*

The distinction between them (theoretical reproductive capacity
and the realised reproductive performance) is dear,

28*

Countries populated by members of the oaucasoid race tend to have a
lower birth rate than countries populated by nan-caucaaoids*

30*

(For onsaple), aethers 19 Years of age and under are the most fertile
and fertility decreases with increasing age*

3iu

There is a tendency for the industrialised caucasoid countries of
the world tx> have lower death rates, Just as they have lower birth
rates*

35*

(Conversely), a country with a high death rate also has a high birth
rate*

37*

Seme biologist point eat that the human race is actually enjoying a
"breeding storm" notwithstanding wars, famines and disease*

38*

In 1630 approximately J|00,000,000 inhabited the earth* By 1030 *fa*s
number had doubled* B y 1900 the m a k e r had increased to 1,600,000,000
and the. total at preseat is over 2,000,000,000 with am annuel, increase
of 20,000,000 or roughly one per cent*

39*

It is predieted that by 1999 there will be 3,300,000,000 people on
earth*

Principle H

— The conservation of natural resources is a logical conse­
quence of men*s understanding of the interrelationships
among living things and between the living and nonLlvlxg
parts of the environment*

263

MEAM SCORE .5 - 1*50

8*

(Since) the human community Is completely dependant upon the earth**
crust and ite resources, a prise objective human activity should be
tbs vise use of these resources*

9*

Outstanding geographers point out that any nation, if it Is to sup**
port its population and nalntaln a high standard of living anowg
its people, requires five d e s s e s of resources* First, it oust have
an abandonee of fertile soil; second, an adequate supply of Minerals;
a sufficient and dependable supply of fuel and power; fourth, a
sufficiency of timber; a relatively high proportion of its people
must be of hereditarily high biological quality*

10*

Of the resources listed fertile soil stands formost*

11*

The food problems of the world with its ever-increasing population
can be solved only in terms of the basic medium for food production,
the soil*

12*

Soil conservation (thus) becomes a matter of international concern,
since the unchecked depletion of the soil resources through erosion
and the consequent decrease in food supply are ever present invita­
tions for social unrest and political upheaval*

18* Conservation through ecological engineering is of importance to
human welfare, whether in terms of his food and nutritional needs
or in terms of his mental and emotional well-being*
MEAN SCORE 1 *5 1 - 2 *0 0

1* An understanding of ecological relationships reveals the intricacy,
of the factors in the soil'water plant animal complex*
2*

It should be obvious that the welfare of
life on noi tli is
directly dependent upon an understanding of these factors*
>

She study of food chains and the phases of ecological succession
reveals the fact that a disruption of any one of the links in a
given sequence can seriously affect the entire eoaqplex*
It* Man, (therefore), in his agricultural and industrial pursuits must
consider the biological and ecological principles which underlie
his activities*
5*

He (man) should ronamber that he cannot oonquer nature*

26k

7*

He (nan) should constantly be aware of the social, economic and
implications of man»ialtiated disruptions of the ecolog­
ical pattern*

13,

Peace with hunger cannot be peace for long*

111*

Closely related to soil conservation la the conservation of forest,
grasslands, water resources and w ildlife* A H are a part of the
soH-water-plaat-aniJBal complex*

15*

The wise use of our forest, gras elands, and the land under eultiva*
tien leads to batter control of the water and wind forces causing
erosion*

16* Where forest, grasslands, and hedgerows exist, one will find environ­
mental conditions suitable for wildlife*

19* With regard to ninaral, fuel, and power resources, it should be
recognised by all that Anerlcan has become great because of her orig­
inal store of geographic goods and not necessarily baoauae of her
social and political lnstltutlonse

22, 16 pronote successfully the conservation of our natural resources,
whether soil, ninaral, fuel, tinber, or faunas, requires the develop-*
neat within each of us of an ecological conscience*
23*

2a the words of the late dido Leopold, "The practice of conservation
nust spring fren a conviction of wbat Is ethically and eethetlcally
right, as well as wbat is econonically expedient* A thing is right
only when it tends to preserve the integrity, stability and beauty
of the oonuonity and the cn— inlty includes the soil, water, fauna
and flora, as well as people*
MEAM SCORE 2*01 - 2*50

6* At best he (nan) can nerely cooperate with nature on the terns and
under the conditions she sets forth*
17*

Where wildlife abounds nan has an unexcelled recreational outlet*

20*

Her natural resources of coal, iron, copper, and other basic ninerals
together with her resources of oil, timber, and ground water were
the greatest on earth and upon these resources was constructed the
greatest industrial civilisation known to nan*

2-L* As a noted economist states it, "The greatness of Anorl new has been
the greatness of our continent - its sweep, its varied resources*
its abundant vitality* We have what other ntLoxn go to war to

26$

AREA TL
Evolution
The Specific Objectives
1* 2s vutorstaad the dsvelopamnt of the concept of organic evolu­
tion Aron the historical viewpoint*
2* lb understandthe history of the development of living things
la the coarse of geologic tine*
3* lbrecognise and appreciate the validity of the various sources
of evidence supporting the fact of organic evolution*
li* To understand the Theory of Natural Selection*
5* To study the evolution of nan*
Principles
1* Svery kind of animal and plant living today has descended*
with modifications* from organisms which have lived la the
geologic past*
2*
The evolution of living things is* in the broadest sense, pro­
gressive not regressive in nature*
3* Germinal variation is essential to the continuance of evolution,
ii# The interaction of organ! sms with their environment results la
a natural selection' of certain organisms* The ultimate conse­
quence of this selection is the origin of new species*
The Assignment
Biological Science Lecture Syllabus* pp* 217-293*
Principle I - Every kind of animal and plant living today has descended*
with modifications* from organisms which have livsd la the
geologic past*
MEAN SCORE *5 - 1.50
1*

Biological evolution is a principle which states that the kinds of
animals and plants living today have descended from different forms
that lived la the past*

2*

The essential point (concerning biological evolution) is that apecies
are not static but have changed la the past* are changing now*
will oontlnue to change la the future*

3.

Biological evolution is concerned with
the changes that
have occurred la living forms from the first primitive living sdbstance to m o d e m organisms*

266

n *

(These) preserved forms* the fossils* have told man most of what he
knows concerning the evolutionary history of life*

308*

The most direct evidence that all living things hare developed by
evolution Is the evidence of fossils*

312*

From the study of sequence (of fossils) It becomes readily apparent
that the simpler foxes of life appeared first and that more complex
forms followed* to be followed in torn by organisms still more ccapleata

320*

ati other evldenoe (besides that based on the fossil record) that
supports the principle of evolution Is based on one fundamental
assumption* It Is that similarity of organisms indicates relation­
ship and that the degree of closeness of similarity ruts essentially
parallel to the closeness of kinship*

322*

On the basis of the assumption that similarity of structure indi­
cates relationship due to inheritance from a common ancestor the
entire system of classification Is a genealogy of living forms*

330*

Evidence from the study of comparative anatomy supports the theory
that animals are basically alike and hence related even though they
differ in superficial appearance*
MEAN SCORE 1*51 - 2*00

It*

Biological evolution does not attempt to explain how life originated*

28*

During the time when sedimentary rock is being formed*
1■
Plants are occasionally burled within the sediment* Asms of these
f O £ M are preserved*

29*

This (preservation) Is particularly true of the hard skeletal parts
of organisms* though sometimes even the softer body parts or their
form are preserved*

32*

By means of a study of the sequence in time in which the rock layers
have been formed plus a study of the fossils contained in the rooks*
It h a s 'bean possible to trace the history of living things on earth*

33*

By various means it has been possible to determine the approximate
age of the rocks* with the result that a time scale has been made
of the history of the earth's surface and of the history of life on
the earth* Ibis Is known as the Geologic Time Seale*

35*

What ever the cause or the manner of the origin of life it Is gener­
ally agreed that the first forms of life were comparatively simple*

267

36*

It has been suggested that these first living things were protein
in nature and that they had the ability to use inorganic sources of
energy*

39*

The development of chlorophyll or a chlorophyll-like substance
probably occurred very early*

h3«

(It is also reasonable to assuae) that after the appearance of
simple cellular plant-like forms, life divided into two streams*
One of these streams produced the modern plants while the other
resulted in the modern animal so

hit*

% e r e are forms living today that are neither plant nor animal in
the strict, sense*

U6*

The first animals were the invertebrates and of these the singlecelled Protosoa appeared first*

U 7*

Qie sequence of developnent of the remaining invertebrate types is
in doubt* but on tbs basis of structural complexity it was probably
as follows* After the single-celled Protosoa came the colonial
Protosoa*

68*

One should not conclude from a discussion of the sequence of evolu­
tion that it occurred in strictly serial fashion* beginning with the
protosoa* Such is not the case*

69*

The exact sequence of evolution is unknown*

70*

It is generally agreed that evolution has not proceeded in a straight
line* but rather that it has branched like a tree*

137*

In reptiles the land egg developed and they were freed forever from
the necessity of visiting ponds and streams for reproduction*

152.

The major structural changes that occurred during the evolution of
birds are practically all adaptationa to aid in flight*

226ft

All primates Including man evolved from a common ancestor*

229*

(Sms)* man it should be understood* did not evolve from modern
monkeys or apes* but both (man and modern apes) evolved along
soparate paths from a common ancestor*

291*

Early in the history of life the stream of evolution divided Into
two branches* the animals and plants*

292*

The separation of living things into two kinds occurred while life
was still in its simple cellular stage*

268

293#

?he first plants wars probably single calls that differed from their
-■i-fi relatives by having chlorophyll#
*-

309,

Fossils are the remains of animals and plants that lived during the
. past ages#

310#

(Fossils) may be foot prints, animal burrows, leaf prints or any
sort of indications of past life#

311#

It is possible to determine the approximate time when fossil forme
lived and also to determine the sequence of their appearance on
earth#

313#

Has order of appearance of animal forms is first the simpler inverte­
brates, then the more complex invertebrates#

31ii#

The complex invertebrates were followed by the primitive vertebrates,
the ostraooderms#

315#

(Following the appearance of the ostraooderms) the fish then evolved
and the amphibians came later, to be followed by the reptiles, birds
npH mammals#

316#

Many of the forms that lived in the past are no longer present# It
is true that representatives of all great animal groups can be found
on the earth today, but countless forms related to each of the forms
near living have ceased to exist#

317#

Each major group evolved in its turn and produced a myriad of forms
which spread over the earth into every available habitat# Then
•aoh group deolined, leaving a few hardy mashers to continue the
struggle for existence, but never again to fluorish and to dominate
the earth#

318#

As each group declined in numbers and types, a new group would
appear# It (the new group) would produce millions of individuals
aad many new forms and then it, too, would eventually decline#

319#

(Finally), the mammals appeared and today man, as a representative
of this group of animals, dominates the living scene#

321#

The validity of this assumption (that similarity of organises in­
dicates relationship) is apparent when it is considered in relation
to Human kinship # It is well known that s o w identical twins are
so alike that their friends and even their families have difficulty
In distinguishing between thma# This likeness is due to their
common heredity# Identical twins have the same ldLnds of genes be­
cause they develop from the same fertilised egg# S m s both likeness
and relationship are as d o s e as they can possibly be in aay two
living organisms#

269

The next most closely related humans are offspring, xaot identi­
cal twins, of the same parents* These are known as siblings* They
are less allies than identical twins sad also their relationship is
net quite so elose because thay develop from different aygotes*
They receive many of the sane kinds of genes bnt also maay different
kinds of gsnes*
Cousins represent a human relationship that is still farther
removed from the identical twins* Their relationship is not se
olose as between either idantloal twins or siblings because their
ossaon ancestors are grandparents* Thay hare fewer like genes la
common, and they also have fever characteristics la ciamon*
Individuals of the same race hare many characteristies la
common, hence must here a common heredity from a common ancestor,
but the ancestor lived many generations ago and the similarities
are fewer than those found In cousins and siblings*
323*

All IndiTiduals belonging to a species are alike, and being related,
they all hare a common ancestor*

32ii* (Likewise), all species that are alike are related*
325*

This relationship (between species) is Indicated la the system of

classification by placing similar species In one genus* Hence, the
animals or plants belonging to a genus are related* Qenera that
are alike are grouped into families and like families Into orders*
Like orders are grouped into classes and classes Into phyla* F i n a l ­
ly all animal phyla are grouped on tbs basis of similarities Into
the animal kingdom and all plants into the plant kingdom*

326* Bren the plants and animals hare some characteristics In common,
such as cells and protoplasm, so that they too show relationships*
32?*

The logical conclusion (based on the genealogy of living forms) is
that all living things are related*

328*

Some (living forms) are more distantly related than others, but the
evidence of a common ancestor is to bo seen even in the most ills
similar of forms*

329*

If this relationship (among living organisms) is accepted it fol­
lows that evolution must hare occurred; for if no change had taken
place all living things would be alike*

331*

In some organisms the similarities are obscured by modifications of
organs as a result of adaptations to the environment*

335#

During the embryonic development of salmis similarities appear that
would never be suspected on the basis of a comparison of
t-o*

270

336,

* that differ only slightly as adults such as the. dog and
wolf or m
and ape are so similar during the early stages of develop­
ment that it is impossible to tell then apart* fray look erectly
alike* During the later stages of development the differences that
are visabie in the adult begin to appear#

337*

Animals that are widely different as adults are more easily dietinguished as eatoryos* tout some similarities remain in the early
stages#

350#

411

35U#

By comparing (the) structure (of vestigial organs) with similar
organs in related forms it becomes apparent that they are vestiges
or remnants of fully developed useful organs*

*

*i- iwfiiwHng h h have certain vestigial anatomical struc­
tures that have no apparent use#

MEAN SCORE 2*01 - 2*£0
/

5e

No one knows when or how the first forms of life appeared on earth*
tout there are several interesting theories*

6* The Special Creation Theory states that all living things ware
crested within a short space of time immediately after the earth
was made# All things were created at this time* and there has been
no change in any of the living things since this time*
7*

According to the Spontaneous Generation Iheory it was once generally
believed that* given suitable environment el conditions* non-living
matter could font into oomplete* complex living things such as in­
sects* frogs* and fish*

9#

The Physico-chemical Evolution Theory assumes that st one time dusk­
ing the history of the world conditions were such that very simple
farms of life arose through the combination of non-living matters

10*

The physico-chemical theory is somewhat similar to that of spaatas*
eous. generation# The difference is that aecordJj* to spontaneous
generation the production of living things from non-living occurs
constantly while according to the physico-chemical evolution theory
it occurred only at som* remote tin* in the earth* s history
has
not happened since# Also spontaneous generation supposes that oo*plex organisms arise from, non-living matter* while the physico­
chemical theory assumes that only very simple forms of life arose
in this fashion and that all modern* complex forms have evolved from
the primitive forms*

30#

(These) preserved animal and plant ions 1us are called fossils*

/

271

31*

With the lifting of tbs continents the rocks containing the fossils
become exposed to weathering and as the rooks wear away, sone of
these fossils are exposed so that man can find them and study them*

37*

There are certain bacteria living today that do not need plant food
(produced by the action of chlorophyll) as a source of energy, but
can obtain the energy they require by causing certain chemical re­
actions in inorganic matter*

38#

The first living organisms were probably of this sort (similar to
the bacteria which do not depend upon plant food) and later evolved
into forms that utilised the sun as a source of energy*

ho*

These forms (containing chlorophyll or a chlorophyll-like substance)
were than able to capture the energy of the sun and to store this
energy la the form of food*

)

u

ill#

No one knows at what stage the substance of these early living
things became protoplasm as we know it today, nor can we say when
this protoplasm became cellular*

1(2# The early stages of evolution are lost in antiquity, but It seams
reasonable to assume that they occurred very early In world history*
ii5*

(Euglena Is an example of an organism that is neither plant nor
animal in the strict sense)* It has animal traits such as gullet
and a food vacuole and also the characteristic plant trait,
chlorophyll*

US*

Colonial Protosoa are made up of aggregations of cells all of the
same type (showing no differentiation)*

U9*

The colonial stage was, probably followed by a differentiation of
certain of the cells (making up the colony) to bring about division
of labor*

90#

(Differentiation means that) within a d u s t e r of cells -*»v4we up
the colony some would be specialised for food getting, others for
reproduction and still others for other functions*

51*

The next step (following differentiation) was the arrangement of
these specialised cells into layers*

52.

The sponges represent the stage in evolution in which specialised
arranged into layers, being made up of loosely integrated
cells arranged in an outer and an inner layer*

55*

(In Coelenterates) the cells within the two cell layers become more
closely integrated so that they may be called tissues#

272

$7*

A third cell layer appears next between the original two to increase
the complexity of the organisms. The modern flatworas are repre­
sentatives of this evolutionary step*

62*

The next evolutionary advance (over the flatworns) was the develop­
ment of segmentation* as in modern annelid worms#

63* Segmentation is where the parts of the body are repeated in a
pattern from anterior to posterior*

serial

6km

The arthropods such ae the crab* crayfish* insects* and spiders
probably evolved from the early primitive annelids* for they retain
the segmentation of the annelids to a narked degree*

65*

(The arthropods added many new features (to those of the annelids)
including an external skeleton of chi tin and jointed appendages*

66m

The noiluaks* such as the oyster and the clam* became specialised
in the development of an outer protective shell*

67*

The eehinoderms evolved with a five-rayed body pattern and a special
type of locomotion by means of tube feet*

71*

Following the analogy of the tree* the earliest forms of life would
represent the base of the trunk* The trunk immediately splits into
two main stems* one stem becoming the first animal forms and the
other stem the primitive plant fozms* The base of the animal, stem
represents the primitive Protosoa from which a branch extends later­
ally to represent the development of the modern Protosoa* Another
branch represents the modern appendages* Dae main stem continues
upward as the primitive eoelenterates and from here several branches
diverge* One branch leads to. the flatworms and roundworms* another
to the annelids* another to the annelids* and another branches to
form the eehinoderms and the chordates which evolve into the verte­
brates* The annelid branch separates into two smaller branches*
one bee eating the arthropods and the other the moilusks*

72*

The vertebrates evolved from the invertebrates*

73*

The vertebrates appeared early in the history of life on earth#

76.

In general (vertebrate) evolution was directed toward a type of
animal having greater locomotory powers than the invertebrates
possessed*

77*

The invertebrates were sluggish* slow-moving or sessile animals#
while the vertebrates became fast moving and agile*

78*

It is probable that the first vertebrates appeared in fast-flowing
fresh water streams where swimming powers were essential to pre­
vent being swept Into the seas*

n

273

79*

The adaptations that developed in the vertebrates include an Inter­
nal supporting axis, the vertebral column* segmented body muscles
that permitted a lateral bending of the body to attain forward
propulsion and fins to give leverage for the muscular action*

96*

The next advance (above the sharks) In the evolution of the verte­
brates was the appearance of the bony fish*

97*

(These) fish developed a skeleton of bone while the forms that
evolved into m o d e m cyolostcmes and sharks retained the cartilage*

98*

The fish that developed their skeletons of bone are Important be­
cause they not only produced the myriads of m o d e m fish and salt
water fish* but also gave rise to the land living vertebrates in­
cluding man*

99*

The bones of these early (fish) forms made up the internal frame­
work of the body and also covered the tops and sides of the skull*

100*

The pattern of skull bones laid down In these (early) fish can be
traced with modifications Into almost every later vertebrate type#

101*

Even the parts of the human skull can be compared with the individual
bones of these early fish skulls*

102*

An Innovation just as important to vertebrate evolution as the bony
skeleton appeared (in the primitive bony fish)* This was the devel­
opment of paired lungs*

118*

The paired bones (below the humorous In- lobe-finned fish) are simi­
lar In position to the hand and finger bones*

119*

The paired bones (below the humorous la lobe-finned fish) Is com­
parable to the radius and ulna (of land animals)*

121*

(Sons of the lobe-finned fish) became adapted and evolved Into
amphibians*

123*

In amphibians lungs replaced the ancestral gills*

129*

While the success of amphibians In making the transition from water
to land was a tremendous evolutionary step It was not quite com­
plete* The aaphibia started the parade to land* but they never
quite succeeded In leaving the water completely* for when It came
time to reproduce they had to return to water*

130*

M o d e m amphibia* among them the frogs and toads* ire still doing
thi# (returning to water during breeding activity) while many of
the salamanders live permanently in water*

M

27k

131*

Reproduction of any vertebrate animal most necessarily occur in
water* Eggs and aperms need water to unite* The sabxyo needs
water in which to develop*

132*

The problem was to evolve a mechanism for creating this aquatic
environment (necessary for vertebrate reproduction) an land so
that reproduction and development could take place*

139*

The (land) egg contained all of the environmental conditions nor­
mally found in ponds and streams and could be laid anywhere on land*

lkO*

Internal copulation developed (in reptiles) as a necessary repro­
ductive function to bring the sperms and eggs together in a moist
medium*

lUl*

The reptiles made use of the freedom provided by this new reproduc­
tive mechanism and evolved into many different types which entered
practically all of the available land habitats*

1U3*

The reptilian body as a whole became adapted to land living*

11*6*

Die birds evolved from the reptiles*

1U8*

The only reason for identifying these skeletons as birds is the
presence of a faint impression of feathers*

163*

The first mamoals were modifications of a primitive group of flesh
eating reptiles*

16U*

Thefirst mammals were small and probably were no bigger than modern
mice and rats*

167*

Same of the characteristics that developed in mammals include a modification of the reptilian mode of reproduction* warm blood* a
better developed brain* and a change in the position of the limbs*
Mammals retain their young within the body
the mother until they
are quite well developed* They also have special glands* the mannary glands* which secrete milk for the nourishment of the young*
They are warm blooded and have a four chambered heart so that the
production of energy is M gHarr> than in reptiles* The brain is
large* resulting in a high degree of intelligence* and the limbs
are directly under the body with the knees directed forward and the
elbows back* This position of the limbs supports the body and en­
ables the development of rapid locomotion* The teeth of mammals
are quite specialised* and the ear drums are sunk below the sur­
face of the head* Hair is a characteristic body covering*

%

*

178*

*

(la placental mammals) this longer period of development before
birth presumably gave these mnmmals an advantage for thay hare
flourished and evolved into many successful animal types* incluriing aus*

27$

196*

(The primate) brain la highly developed, resulting in a high degree
of Intelligence*

207*

A well developed cerebrum is essential for intelligence*

218*

Han differs froai the apes in many ways, bat the differences are all
differences of proportion of basically similar parts*

219*

The major differences (between man and the apes) are related to
methods of locomotion and to the growth of the brain*

22$*

(The human) brain is much larger, being two or three times greater
than in apes, and man Is more Intelligent*

227*

(The common ancestor of all primates) was one of the most primitive
of mammals, the aboreal Insectivore*

228*

Each of the modern types of primates evolved along a separate path '
resulting in lemurs, tarsias, monkeys, apes and men*

23U*

The most positive evidence of nan's evolution consists of a number
of human fossils*

23$*

(The human fossils) Include the PHtdown man, (Boanthropus dawaonl)»
the Heidelberg man (Homo heidelbergensls)* the Java man (j&jEocagT
thropua ersctas)* the Peking nan (sinanthropus peldnensls)* 4 h e ~
Neanderthal man (Homo neanderthalenaie) and tfm Cro-Magnon nan
(Hone sapiens)*

238*

It Is not certain that each of the fossil nan represents a step In
a single evolutionary path*

239*

It is possible that early in human evolution there was a divergence
so that two or more lines of human evolution nay have occurred*

283*

Modern man evolved during the late Pleistocene and became sub­
divided Into several racial types or sub-species*

285*

(Uhile) most human beings fit into one or the other of these cate­
gories (Kegroid, Mongoloid or Caucasoid), there are nany intermediate
types and it is probable that at present there Is no such thing as
a pore race*

29U*

The early plants lived In water*

29$*

Many of the descendants of the early plants, the thallophytes, still
remain (living In water)*

296*

Some of the thallophytes (descendants of the early plants) have
developed Into large complex, many-oelled structures, though naay
are still single-celled*

276

297*

Baring the tins (Devonian) whan the lobe-finned fieh were climbing
oat on l a d to evolve into the amphibians* plants were also moving
oat of water*

296*

(In fact)* it is very probable that the plants prsoedsd the animals
on land* for the animals coaid not have remained there had there
been no food available*

307*

Today they (flowering plants) are the dominant land plants* though
representatives of other forms still exist*

332*

(An example la which similarities are obscured as a result of adapta­
tion can be seen In) the skeletal structure of the arm of man* the
foreleg of a horse* the flipper of a whale* the wing of a bat and
the wing of a bird* A H are fundamentally the same bat In each form
the bones have become modified In relation to the particular function
that each performs*

333*

Structures that hove a basic similarity bat which have developed
special functional adaptations are said to be homologus*

33U*

The study of embryology also contributes evidence of the fundamental
similarity of animals*

338*

For example (of similarities in the embryo) all animals begin devel­
opment as a single cell* the sygote* All animals above the Protosoa
go through a period of cell division which ends In the formation of
a two layered gaetrula* All animals from the flatworms up go through
another common stage* which is the formation of the third layer of
cells* the mesoderm*

339*

Another very striking example of related but different organisms
going through sim ilar embryonic stages is that of the development
of gill slits in the embryos of all vertebrates* In fish the gill
slits appear in the embryo and remain la the adult as functional
structures* but in amphibia* reptiles* birds and mammals they appear
for a short time only during development and then disappear before
birth*

3U0*

The appearance of (these) gill slits In embryos indicates a genie
complex causing their development* The only possible explanation
of the presence of these genes in all vertebrate embryos is common
anoestoxy*
4

3iil*

On the basis of similarities found among all animals during embryonic
development a theory has been proposed mhioh states that during
embryonic developaant every animal goes through developmental states
that correspond to evolutionary stages which the ancestors of the
animal have passed through* This is the Theory of Recapitulation*

277

3U2,

An example to Illustrate the Theory of Recapitulation follows: The
human eatoryo starts as a single cell, the sygote* This sygote sup*
posedly represents the single cell stage of erolution that ocourred
at the very beginning of life on earth* The next e^ryonle stage
is cell division of the qrgote into a "hollow ball of cells" stage
called the bias tula, which supposedly corresponds to the tine in
evolution when colonial Protosoa represented the highest develop­
ment of life* Ih the following divisions of the sygote the mabryo
becomes atwo-layered blastula, which corresponds to the two-layered
animal stage represented in Modern farms by the codenteretes* The
next major esbryonie step Is the formation of mesoderm which pre­
sumably followed the evolutionary developnent of three—layered forms*
The flatwoms of today represent this evolutionary step* The appear­
ance of gill slits in human embryos represents the fish stage of
human evolution*

3h3*

(Thus), it is possible to relate most of the stages of esbryonie
development with a corresponding stage in evolution and also with
a modern animal type that apparently stopped its evolutionary
daweiopsnnt at one or another of the evolutionary steps*

3Wu

The validity of this theory (of Recapitulation) is questioned, par­
ticularly in relation to its extension to include all embryonic
stages and structures in an evolutionary sequence*

3U5*

Obviously no animal can go through its entire evolutionary history
in the short time it takes for embryonic development*

3U6*

Many stages (in embryonic development) acre telescoped and many sore
are left out entirely*

3U8*

(Consequently), it is impossible to read the entire evolutionary
history of an animal in its embryonic development,

3U9*

(Nevertheless), it is probable that the embryo does repeat a few
of the evolutionary stages of its ancestors, and in so far as it
is possible to reoognlse these, the Theory of Recapitulation is
valid*

351*

The appendix in man is such a (vestigial anatomical) structure*

355*

(For example), the human coccyx is a remnant that represents the
tail vertebrae of other primates*

356*

The development of the coccyx in any individual is due to genes
which com* from its ancestors*

357*

(Presumably, therefore) nan* a ancestors had genes causing the devel­
opment of a tall which in m o d e m forms have bean reduced in their
effect so that a renamnt only develops*

278

358*

No otter explanation (except a genetic one) la logical on the basia
of our knowledge of inheritance*
MEAN SCOBE 2,51 - 3.50

8* According to, Van Helmont, a aixteenth century Dutch scientist* the
combination of soiled linen and cheese would produce nice* The
Nile river and plus the teat of the sun supposedly was able to pro­
duce both nice and rats*
12*

The earth is constructed of a central core and a crust that lies
outside the core* The crust is a shell of rock that varies la
thickness* In places it is covered with water forming oceans*
In otter places the rock is exposed, forming the continents*

13*

The rock of the continents is exposed to the action of wind* rain*
temperature changes* and plants and animals* which result in a
gradual disintegration or "weathering" of the rock*

lit*

The loose material (thus) formed (by weathering action on rook)
covers the earth as the soil*

15*

Some (of this) soil is wasted away by rain and streams and eventual­
ly deposited as sediment in lakes and oceans* where it settles te
the bottom to form layers of and or sand* As time passes more layers
are added on top of the earlier-formed ones and eventually all of
them become rook because of chemical changes and the compressing
effect of weight*

16*

Bock (fowned by the deposition of water borne deposits is called
sedimentary rook because of the materials out of which it is made.
and also is called stratified rook because it is formed in layers*

17*

Weathering* when continued over millions of years* gradually wears
away the exposed rocks and the continents become flattened*

18*

Am the continents wear away the edges of the oceans become filled
with sediments and the water of the ocean gradually overflew* the
land*

19*

The continents as a whole also rise and sink slowly over long inter­
vals of time* and when they sink the water of the ocean inundates
parts of the continent*

20*

(Because of the changing relationship between land and water)greet
arms of the ocean cover vast areas of the continents*

21*

(Hudson Bay
is an example of an a m of the sea havingmovedinover
a vast area of continent)*

279

22*

Into (theae) shallow continental seas wore sediment is carried and
wore sedimentary rock is formed* Eventually the continents rise
again# 2he oceans recede from the continents and the sedimentary
rock becomes dry land*

23*

Usually during (these) periods of uprising continents* the earth's
surface buckles in places and nountains are formed*

2b#

Following the rise of the continents and the formation of mountains
weathering again begins its leveling action through rock disintegra­
tion and sedimentation*

25#

M s cycle of rising and sinking continents has occurred many times
in the past history of the earth and during each cycle new layers
of sedimentary rock are formed*

26#

The layers of sedimentary rock laid down at the beginning of a cycle
are always underneath those laid dawn later and also the layers of
an earlier cycle are always beneath the layers of a later cycle*

27#

Occasional exceptions to this rule (law of superposition) occur when*
during mountain formation* the buckling of the earth results in a
folding of the rock layers*

3b#

Copy of Geologic Time Scale as given on page 217 of Syllabus fbr
Biological Science*

53*

The inner layer (in animals with two cell-layers) functions mainly
in food getting while the outer layer is primarily protective* but
also contains sensitive cells that can respond to environmental
stimuli*

5b*

The Coelenterates represent the next probable evolutionary advance
(above the sponges)*

56#

(In Coelenterates) the outer layer is protective and sensitive*
while the inner layer is concerned with digestion*

58*

Flatwom embryos contain an external cell layer* the ectoderm* an
internal cell layer* the entoderm* and a layer in between known as
mesoderm*

59*

The ectoderm (in flatvorm embryos) develops into an outer layer
which is still primarily protective in function and also retains
its ability to receive stimuli from the external environment*

60*

The inner ectoderm (in fLatwom embryos) becomes the lining of the
digestive tract and is digestive in function*

6L*

(In flatwares) the mesoderm in the middle develops into muscle and
other internal body organs that make up the bulk of the organism*

7U.

The vertebrates appeared about 550.000.000 years ago*

.
.
.

75

Hie vertebrates appeared during the Paleosoic Era.

80

The ostracoderms are the most primitive vertebrates known.

81

The ostraooderms lived about 1*50.000,000 years ago.

83.

The ostraooderms had fish-like bodies and tails that ranged from
six laches to one foot la length, and they ware covered with thick
bony scales. The mouth was a transverse slit and jaws were absent.

81t«

In many ways the ostraooderms resembled the modern cyclostomes,
which are the most primitive of modern fish.

89.

0111 arches are cartilaginous or bony supports for the gills and
lie just behind the mouth on each side.

90.

( m sharks the first pair of gill arches) one on each side, moved
forward, became hinged in the middle and took on the new function
of opening and dosing the mouth.

91.

(In sharks) the scales lying near the edge of the mouth moved la to
rest upon the jaws and beoome teeth.

92.

The transition from gill arch to jaw bone is evident in the develop­
ment of embryos and the similarity of scales to teeth can be seen
on modern sharks.

93.

The sharks also developed paired fins.

9k•

The aoquisltlon of jaws, teeth, and paired fins enabled the sharks
to leave the bottom of the streams and swim freely in the water.
The fins made control of body movements possible and the jass and
teeth were useful in catching prey.

95.

These modifications made greater freedom of movement possible and
the sharks migrated into the oceans where they are found today.

103.

It is probable that lungs developed during a time when seasonal
climatic changes were extreme, restating In a periodic drying up
of stremns and ponds.

105.

The early bony fish with lungs branched into three groups, the ray*
finned fish, the luz^ fish, and the lobe-flxmed fish.

106.

The ray-firmed fish evolved into the modern fish.

107.

The lungs of the ancestors (of the m o d e m fish) became modified
into an air sac or bladder that moved to the dorsal side of the
body cavity.

281

108*

(The air sac or bladdar in modern fish) is used to change the spe­
cific gravity of the body enabling the fish to change Its eleva­
tion In the water with ease*

109*

The lung A s h of today include three forms* One type lives in
Australia, the second in Africa and the third in South imerica*

110*

(Modem lung fish) live in ponds and streams that dry up period­
ically and when this happens the fish burrow into the mud of the
bottom* There they remain until water returns to the pond*

112*

The characteristics of the lobe-finned fish that make possible the
transition from water to lend include the lungs, an open connection
between the external nostrils and the throat, and fins that were
rounded and strong, containing both bone and muscle*

113*

The function of the lungs in an air breathing animal is apparent*

llh*

The internal connection of the nostrils to the throat (in the
primitive lobe-finned Ash) permitted breathing through the
nostrils*

115*

The bone-supported fins (of the primitive lobe-finned fish) gave
sufficient support to permit locomotion across dry land*

116*

(The structure of the skeletal support of the fins of the lobefinned fish is as follows) one bone connects with the shoulder
skeleton* Extending from the end of this bene within the fin are
two bones lying side by side* From the ends of these bones a
series of small bones branch to support the free end of the fin*

117*

The single bone that connects with the pectoral girdle is com­
parable to the humorous of land anlamle including man*

120*

The lobe-finned fish lived during a time whan seasonal changes ware
great, and it is believed that some of thma were forced to become
adapted to living on land or die*

122*

The amphibians whloh evolved from the lobe-finned fish ranged in
slse from about two feet in length to individuals equal in also to
modem crocodiles* They had long, slim Ash-like bodies with long
tails* Paired limbs supported these bodies by means of an internal
bone structure similar to that found in the human skeleton*

12b*

(In amphibians) air was forced into the lungs by swallowing*

125*

The ear made its first appearance in amphibians*

126*

One of the ancestral gill slits persisted as a tubular opening from
the throat to the side of the head* This tubular opening known as
the eustachlaa tube, was closed over at the outer surface by a mem
brane, the ear drum*

*

282

127#

Just beneath the membrane a bony remnant of one of the gill arches
served as a connecting link between the ear drum and the internal
ear*

128*

Vibrations of the ear drum were caused by sound wares and these
vibrations caused movements in the ear bone, which in turn moved
parts of the inner ear thus setting up nerve impulses which were
carried to the brain*

133*

Some amphibia lay eggs in moist burrows, some use rainfilled hollows
in trees, and one modern toad deposits its eggs In little pits on
its back*

13b«

None of the (amphibian) schemes (for obtaining an aquatic environ­
ment for fertilisation) was very successful and the amphibia, which
started the procession to land, fell backward in the evolutionary
race*

135* It remained for the reptiles to solve the problem of reproducing on
land*

138*

The egg that developed In the reptiles consists of a water filled
sac, the amnion, that surrounds the developing embxyo, a yolk sac
containing food suspended from the embryo, and another sac that
serves as a respiratory organ* All of this is surrounded by a
tough, porous protective shell*

lit2*

Some reptiles developed wings and flew while others turned back in­
to the water*

lliii*

A thick, tough, horsy body covering prevented excessive water evap­
oration* The heart became more efficient and the brain more highly
developed, and many other internal organs advanced beyond those of
the amphibians*

Iii5*

The oldest known birds were scarcely more then feathered reptiles*

1J»7*

The skeletons (of primitive birds) was typically reptilian, with a
long tall and teeth attached to the jaws* Bach wing had three
fingers extending from it and these bore daws*

lh9*

It is still questionable how flight evolved*

150,

One theory (as to how flight evolved) states that these early birds
lived In trees and learned to glide from branch to branch*

151*

Another theory (as to how flight evolved) states that the aneestoral
birds ran along the ground and with wings outstreched soared Into
the air*
(

283

153.

Feathers serve to streamline the body and to act In the wings and
tall as rasistant surfaces to posh against tbs air.

15U.

The feathers (of birds) are probably Modified reptilian scales.

155.

The brain (of the birds) enlarged, bat without an increase in intel­
ligence.

156.

The parts of the brain that enlarged were concerned primarily with
sight, balance and the muscular coordination needed for flight.

157.

The sternum (of birds) increased In also to afford greater area
for wing muscle attachment and the bones hollowed out, making the
body lighter.

158.

The eyes dereloped Into efficient organs for sight.
lost and a beak dereloped.

159.

The creatures (birds) also became warm blooded and correlated with
this was the development of an efficient circulatory system that
brought a good supply of oxygen to the tissues.

The teeth were

.

160

As a part of the circulatory system (of birds) a four chaebered
heart developed.

161.

The four chambered heart effectively separated the oxygenated blood
from the nonooeygenated blood and so increased the efficiency of
oxygen distribution.

.

162

The reptiles had scarcely began their long evolutionary history on
earth when the mammals first appeared.

165.

(The early mammalian) teeth were sharp and adapted for flesh eating,
but it is believed that they fed mostly on Insects and worms.

.

166

The brains (of the early mammals) ware better than those of the
reptiles, bat not particularly well developed In comparison with
modern aasaals.

168.

There are three major groups of manuals:
marsupials and the placentals.

169.

The monotremes are found only la Australia and Tasmania.

170.

The monotramas are tin most primitive of all mammals.

171.

(The monotremes) still have many reptilian characteristics, Include
lag the habit of laying eggs which hatch in a nest.

172.

The marsupials have a pouch on their abdomens In Which they earzy
their young.

the monotreams, the

281*

173*

The young (of marsupials) are born prematurely end finish their
development hanging onto a nipple within the pooch (on the mother's
abdomen)*

17lu

The kangaroo is the most generally known marsupial* t-hmigh there are
many others* Including the opossum In the United States*

175*

Practically all (of the marsupials)* however* are confined to
Australia and adjacent areas*

176*

The placental mammals retain their young within the body cf the
mother longer than the monotremes and marsupials*

177*

(In placental mammals) nourishment for the embryo is provided by
the placenta*

179*

The Insectlvores are small* primitive* insect eating placentals
such as the mole and shrew*

180*

The carnivores are the flesh eaters and include the seals* walruses*
bears* cats* dogs* weasels* raccoons and others*

181*

The herbivores are the hoofed animals*

182*

Some (herbivores)* such as the pig* cattle and deer* have two hoofs
on each foot* while others* such as the horse have but one hoof per
foot*

163*

Bats are flying mammals*

l6b*

(In bats)* a flap of skin extends between the elongated finger bones
and from the arm to the body to font the wings*

185*

Whales are the largest of mammals*

186*

Whales are entirely aquatic spending their entire life from birth
to death in the water* The body has become streamlined and the
fore limbs have become flippers* The hind legs axe gone* A fishlike tail aids in swimming*

187*

The primates are the group of mammals to which man belongs*

188*

All of the primates are tree dwellers except a few forms like the
baboon and man* who normally live on the ground*

189*

The structural characteristics of primatesare adapted for a life in
trees*

285

190*

(The structural characteristics) of primates Include flexible limbs
that permit climbing and swinging through the trees* Both the hand
and the foot are grasping organs* The thumb and big toe are oppos­
able to the other fingers* Most primates hare a tail that is used
in some as a grasping organ, though in the man-like apes and man
the external tail is missing* The teeth are reduced in number as
compared with those found in other mammals#

191*

The eyes of primates are well developed*

192*

Stereoscopic vision, which permits the formation of a singleimage
from the two eyes, appears (in the primates)*

193*

(Stereoscopic vision) gives greater depth of field and greater
perspective*

19U*

In the monkeys, apes and man a special area, the central pit, is
present on the retina that enables these animals to see greater
detail*

195#

(In the primates) the sense of smell is degenerate*

197*

There are three main groups of primates:
the anthropoids*

198*

The lemurs are small primitive primates*

199*

The lemurs live in Asia and Africa*

200*

Tarsius is (also) a (small primate)*

201*

Tarsius lives in Sast India*

202#

Tarsius is intermediate in development between the lemurs and the
anthropoids*

203*
20U*

205*
206*

the lemurs, tarsius and

The anthropoids include the monkeys, themanlike

apes,

and sum*

Sam monkeys are separated into two groups*
One, theMew World
monkeys, lives in South America, the other group, the Old World
monkeys, in Asia and Africa*
Monkeys are noted for their curiosity*
This (curiosity of monkeys) is due to a high degree of intellectual
development that supposedly is the result of the combined effect
of the well developed brain, the ability to sit up, the opposable
thumb, and keen eyesight*

286

208,

The ability to alt up supposedly has contributed to the development
of intelligence by freeing the hands for use in handling objects*

209*

The opposable thumb enables the monkey to handle objects*

210*

The keen eyesight (of monkeys) enables him to see more things to be
curious about*

211*

Nan also has all of these characteristics (which the monkey has)*
and it is believed that man's intelligence is the result of the
further development of the sane kinds of traits that are found in
monkeys*

212*

The manlike apes include the gibbon* orangutan* chimpansee and
gorilla*

213*

(The manlike apes) are the closest of all the primates to man in
physical development*

21b*

The skeleton (of the manlike apes)

215*

The chest (of the manlike apes) is braod rather than narrow as it
is in the monkeys and other mammal s*

216*

(In the manlike apes) the arms are larger and the legs are shorter
than in man and the big toe is opposable* but the hand is very
similar to the human (hand)*

217*

These animals (manlike apes) have an erect posture when swinging
through the trees* whereas on the ground they usually progress on
all fours*

220*

Man is erect and walks on the ground* This erect posture has re­
sulted la a curved backbone that brings the trunk and head directly
over the hips and thus centers the weight over the legs*

221*

The foot (of man) is modified by a shortening of the toes and the
expansion of the heel bone as a prep in back* The big toe is no
longer opposable but it is in line with the other toes* Han's
foot is adapted for walking and is no longer a grasping organ*

222*

The hand (of nan) differs less from the ape's hand* It is still
primitive and very useful as a grasping organ* The thumb remains
opposable*

223*

Nan's face isdiorter than the apes} the nose is more prominent and
a chin projects from the lower jaw*

22b*

The teeth (of man) are smaller and weaker than the ape's*

is very similar to man's*

287

230.

The earliest nan probably originated during the Pliocene period of
the Cenoeolc era and evolved into m o d e m man during the Pleistocene
period.

231.

The Pleistocene period was approximately one million years long
and was characterised by periods of glaciation*

.

232

(During the Pleistocene period) there were probably four successive
ice sheets* with long periods of temperate to warm climates between
the periods of glaciation*

233.

The warmer periods (of the Pleistocene) were from ten to hundreds
of thousands of years in length*

.

236

This list (above) does not Include all of the human fossils but
does include the best known ones*

237.

There is no final agreement as to the exact sequence in which these
early men appeared*

21*0*

The age of the rocks in which the fossils were found indicate that
the Piltdcwn and the Heidelberg nan lived during the early Pleis­
tocene period*

*. middle
The Java and Peking men. were probably contemporaneous
Pleistocene.

211

during the

21*
2. The Neanderthal and Cro-Magnon men lived during the late Pleistocene*
with the Cro-Magnon man appearing somewhat later than the Neander­
thal type*

21*3.

The Piltdcwn man was found in Piltdcwn* Sussex* England in 1912*

21*
1*. The (Piltdcwn) fossil dates from the first interglacial stage in
early Pleistocene and consists of pieces of skull* most of a lower
Jaw* nasal bones* a canine tooth and two cheek teeth*
21*5.

A few crude t o d s were found associated with the bones (of Plltdowm
man)*

21*
6. The skull of PHt d o w n man is m o d e m in type except for the bones*
which are twice as thick as m o d e m man*
21*7.

The brain capacity (of Piltdcwn man) is

21*
8 . The brain capacity of m o d e m man ranges
21*9.

1300 ml*
from 1200 to1500

The jaw (of Piltdcwn man) is apelike and has a retreating chin*

ml*

288

2f>o*

Tbs «mnine tooth (of Piltdcwn nan) Is also apelike while the cheek
teeth are a type that could be found in either an ape or in a
primitive nan*

251*

The Heidelberg
teeth*

252*

(The Heidelberg jaw) was found near Heidelberg* Germany*

253*

(Heidelberg jaw) was recovered from rock of early Pleistocene for­
mation*

25U*

(Heidelberg jaw) is apelike in that it is large in else and heavy
in build and has no chin*

255*

The teeth and dental arch (of Heidelberg jaw) are human in character*

256*

(Heidelberg jaw) shows some similarities to the Java man and to the
more recent Neanderthal man*

257*

The Java man dates from the middle Pleistocene about $00*000 years
ago*

258*

The first find (of Java nan) made in the East Indies included a
skull cap* three teeth* and a femur*

259*

Java man had some features that were, human in character and some
that were apelike*

260*

The human characteristics of Java man are as follows: the brain
capacity of the skull (9U 0 ml*) is intermediate between apes (600'
ml*) and m o d e m humans (1200 to 1500 ml*)« The median sagittal
crest is absent* This is a prominent ridge of bone that extends
from front to back along the middle of the
in some apes* The
femur has a straight shaft* and the position of the articular sur­
faces Indicates that the muscle attachments were for an erect
posture* The teeth are more human than apelike*

26L*

The apelike characteristics (of Java man) include heavy brow ridges*
Also the forehead slopes back from the brow ridges which makes the
vault of the skull low* The canine tooth of the lower jaw fits in­
to a space between the teeth of the upper jaw* The wisdom teeth
are not reduced* There is no chin* and the hole through which the
spinal cord enters the cranium is visible from behind* This is not
true of m o d e m skulls*

262*

The Peking man was found in a limestone cavern near Peking* China*

263*

(At the Peking find) the remains of three do sen individuals of both
sexes and both young and adults were discovered*

is represented by a lower jaw with attached

26b*

I hero are some differences between the Peking man and Java man* but
thay are not any greater than the differences among modern races of
men*

265*

The Peking
was a tool user because crude stone tools were found
associated with the bones*

266*

Likewise remants of fires were found* indicating that the Peking
man had learned its use*

267*

Many brain cases had been opened from the bottom* evidently by nan
himself* This is interpreted to mean that the Peking man was a
cannibal*

268*

The Neanderthal man was the first human fossil discovered*
#

270*

Since (the original discovery) many skeletons have been found in
the following locations: Western Europe* Gibraltar, North Africa*
Italy* Croatia* Palestine* and Russia*

271*

(The many locations in which Neanderthal finds have been made) in- ,
dic&te* that the Neanderthal mqn bad spread all over Europe*

272*

(Neanderthal man) had heavy brow ridges* a receding forehead and a
low vault to the brain case* Thera is no chin on the massive jaw*

273* The brain capacity (of Neanderthal man) was 1550 ml* which is as
large as or larger than the cranial capacity of modern races* but
it was due to increased capacity at the back of the skull rather
than in the fore part as in modern man*
27b*

(Neanderthal) males were about 5 feet b inches tall and females
about b feet 8 inches tall* The posture was stooped and the knees
slightly bent*

275*

Neanderthal man used flint tools*

276*

Cro-Magnon man was first found in the Cro-Jiagnon vicinity of France*

277*

(Cro-Magnon man) is believed to represent a race of man that re­
placed the Neanderthal type in Europe*

278*

(Cro-Magnon man) was essentially modern* The head was large with
no brow ridges* a high forehead* a prominent and narrow nose* and
a well developed chin*

279*

The cranial capacity (of Cro-Magnon man) was 1700 to

280*

The Cro-Magnon males were

6 feet

or more in height*

1800 ml*

290

281.

Th<* Cro-Magnon people disappeared at the end of the Pleistocene
period and were replaced by m o d e m man.

282,

There is evidence that some of the people living In North Africa,
Canary Islands, Iceland, North Germany, and Norway may be descendents of the Cro-Magnon man.

2814.

The major races are the Negroids, the Mongoloids and the Caucasoids..

,

286

Man has always been nomadic, with, the result that no human group
has remained Isolated long enough to prevent interbreeding with
other races.

287,

The Negroid race includes the dark-skinned people who have curly
hair and long heads.

288,

The Mongoloids are the yellow and the red-skinned people of the
world. They have broad heads and straight hair.

289*

Indians, Chinese, Japanese, Malays and Eskimos are Mongoloids.

290,

The Caucasoid race or Caucasians are usually white-skinned, though
they also have some pigment in their skin. Their head shape may
be long or bread and their hair form Is generally wavy,

299.

Some of the most prominent and successful of these early land forms
were the seed ferns.

300.

(Early seed ferns) grew to the size of
having steam throe feet in diameter.

.
.

modern trees, seme oftham

301

(Early seed ferns) differed from modern ferns not only in slae but
also in producing seeds. Modern ferns do not produce seeds.

302

The seed ferns and their relatives, such as the tree-like horse­
tails and d u b mosses, flourished In wet, swampy ground. Many of
them were preserved after death and changed through compression
within the earth to form coal.

303.

The gymnoapems, represented today by the evergreen, evolved after
the ferns.

30U.

(The early gymnosperms) had straplike leaves rather than the needleshaped leaves present in modern farms (of gymnosperms).

305.

The true flowering plants appeared later, about the middle of the
Mesoaolo.

t

306.

(The true flowering plants) were very successful land plants and
spread over the entire earth.

291

3ii7-

(Furthermore)* many embryos have developed special structures that
have no evolutionary significance beyond the aid they give the
enbryo in survival*

352.

The degenerate muscles by means of which a certain few human beings
can wiggle their ears is another (example of a vestigial structure)#

353.

The coccyx or tail bones of the human skeleton represents another
example of vestigial structures*
MEAN SCORE 3*51 - ll*50

Items number 82* 85* 86* 87* 88* lOh* 111* and 269*
tained from Appendix II#
Principle H

Content may be ob­

- The evolution of living things Is* In the broadest sense*
progressive and not regressive in nature.
MEAN SCOPE 1.51 - 2.00

1*

Evolution seams to be progressive.

2.

Within the total picture* the evolution of individual forms tells
the same story. For example* the horse began as a small five-toed
creature that evolved In a more or less direct line into a large*
single-toed animal*

3*

O s loss of toes (in the horse) was not sudden but gradual* * During
'the millions of years that elapsed while the horse was evolving*
some of the toes became gradually reduced in sise and were lost*
while one on each foot increased in sise*

hm

Other fossil anlmale and plants show this same progressive change
(that the horse shows) by steps from one condition to another*

6*

Anothar explanation of progressive evolution Is natural selection*

9m

Each generation produces many more offspring than can possibly survlve primarily because of limited food supply*

10.

The offspring vary in their ability to compete for the available food
and consequently during this competition some perish*

U*.

The offspring that perish In the struggle for existence are the less
fit* those that survive are the most fit*

292

12*

(Thus) HaturaL S el action results in the survival of the fittest*

13*

The survivors (at any given tine) then overproduce another genera­
tion anrf the competition and selection goes on*
MEAM SPORE 2.01 - 2*50

5*

One explanation of this progressive evolution is orthogenesis,
which claims that there is some unknown farce within the organism
that guides its evolution*

8*

According to the Theory of Natural Selection all organises are en­
gaged in a struggle for existence*
MEAM SCORE 2*5l - 3.50

7*

The Theory of Natural Selection was proposed by Darwin*

Principle III — Germinal variation is essential to the continuance of
evolution*
MEAN SCCRE *5 - 1*50
1*

In order that evolution can occur, it is necessary •that different
kinds of organisms be produced*

2*

One source of new organisms is sexual reproduction*

3*

Each generation of offspring of sexual parents differs in some re~
speots from the preceding generation*

U*

(Offspring of sexual parents differs from the preceding generation)
due to the uniting of half of the genes from each parent in fertili­
zation with the result that an organism somewhat different from the
parents 1s produced*

6*

(The) source of new organisms is limited because the number of dif­
ferent genes that can'combine is limited*

7*

Something besides sexual recombination of genes is necessary before
evolution can continue Indefinitely*

293

8*

Soma change in heredity must have occurred to produce the mill ions
of different living things that have inhabited or still inhabit the
earth*

9*

The additional necessary factor (additional to sexual recombination
if evolution is to continue) is imitation*

10*

This change in heredity is the essence of evolution*

11*

There are different kinds of nutations* all of which involve a change
in the —
of heredity* but the most fundamental is gene muta­
tion*

12*

Gene nutation is a change in a gene that results in the development
of a new inherited trait*

13*

It is believed at the present time that (gene mutation) is the source
of all variations that result in evolution*

22*

We inherit but one thing and that is a complex of genes that is con­
tained in the germ calls*

35* If one thinks of survival in terms of genes* it becomes obvious that
the genes possessed b y the survivors are the ones that are passed
on to the next generation*
37*

Add to this (concept of the survival of genes)* the factors of isola­
tion and mutation and it becomes evident how two or more different
kinds of organisms can descend from a single common ancestor*
MEAN SCORE 1*51 - 2*00

5#

It is known that according to the laws of heredity the degree of
variation in organisms is limited*

23*

Changes in the body such as the enlargement of muscle through exezvclse or the skill and coordination that results from long practice
do not affect the genes in the g e m cells*

25*

Changes within the genes contained in the g e m cells can be caused
by a number of different things*

28*

Most important of all environmental factors (in relationship te
mutations) is irradiation by x-rays*

29*

Earth radiation and cosmic rays also cause genes to change*

3U*

Natural selctlon re suite in the survival of the fltteist (of the
mutants)*

29k

36*

The genes of the individuals that perish are lost and do not con­
tribute to the evolution of the population*
MEAN SCORE 2.01 - 2.50

lU.

Tears ago a Frenchman named Lamarck suggested that changes in the
mechanism of heredity were brought about by the use or disuse of
organs or parts of the body*

15*

This (theory of Lamarck's) is known as the Iheory of the Inheritance
of Acquired Characters*

16*

According to this theory, (of Lamarck) the loss of toes that occurred
during the evolution of the horse resulted from the lack of use of
such toes*

17*

How the use of an organ apparently resulted in its change can be
illustrated by the long neck of the giraffe*
It was supposed that
the giraffe got its long neck by stretching upward in search of
food in tall trees*

21*

As attractive as (the Theory of the Inheritance of Acquired Characters)
is* it is probably not true, because we do not inherit characteristics
of the body that are developed as a result of the direct effect of
the environment*

21** One can listen for a lifetime to good music and can practice day
after day on a musical instrument and one's offspring will be no
more musical than the genes will allow*
26*

In one kind of plant it was found that aging of the seed would induce
mutations*

27*

In the fruit fly high temperatures will cause mutations*

31*

(But) it was found that many more mutations occur than could be
accounted for on the basis of the amount of irradiation present*

32*

Something else (other than naturally occurring rays), still unknown,
causes the bulk of the mutations*

33*

Nobody knows what the unknown factor is that causes the bulk of
mutations*
MEM! SCORE 2*£L - 3*S0

18*

T M m theory (of Lamarck) was very attractive because it explained
so simply how animals and plants became adapted to their environments*

295

19.

(According to Lamarck* 8 explanation) many cave dwelling animals are
blind because they did not use their eyes in the dark caverns*

20,

Likewise (according to Lamarck), the whale became streamlined and
developed flippers and a fish-like tail by living in the water where
such body traits are useful*

30*

After the discovery’ that irradiation caused gene mutation, it was
thought that the naturally oocurrlng rays that come from the earth
and from space would be sufficient to account for all of the nuta­
tions that occur spontaneously In animals and plants*

Principle 17 - The interaction of organisms with their environment results
in a natural* selection of certain organisms* The ultimate
consequence of this selection is the origin of new species*
MEAM SCORE *5 - 1*50
1*

According to the Theory of Natural Selection all organisms are e n­
gaged in a struggle for existence*

2*

Each generation produces many more offspring than can possibly sur­
vive primarily because of limited food supply*

3*

The offspring vary in their ability to compete for the available
food and consequently during this competition some perish*

Um

The offspring that perish in the struggle for existence are the less
fit, those that survive are the more fit*

5*

(Thus) Natural Selection results in the survival of the fittest*

6*

The survivors (at any given time) then overproduce another genera­
tion and the competition and selection goes on*

7*

If one thinks of survival in terns of genes, it becomes obvious that
the genes possessed by the survivors are the ones that are passed
on to the next generation*

8*

The genes of the individuals that perish are lost and do not contrib­
ute to the evolution of the population*

9«

Add to this (concept of survival of genes) the factors of isolation
and mutation and it becomes evident that two or more different
kinds of organisms can descend from a single common ancestor*

16*

(When two groups of organisms of the same kind are separated) new
mutations will occur in each group*

296

17*

New genes (arising in separated groups) will be confined to the
group in which they arose because there is no mating with other
groups*

18*

The result (in isolated groups) will be independent nutation and
selection in each group and hence independent evolution*

19*

If the environment of two isolated groups is the same the evolution
may be parallel, but if it differs it is likely that the two lines
of evolution will be different*
MEAN SCCBB 1*51 - 2*00

10*

Isolation means the separation of Individuals of the same kind from
each other so they cannot mate*

11*

Isolation may result from migration where one group wanders off into
new territory*

12*

Isolation may result from physical changes in individuals within a
single area so that such individuals cannot mate*

15*

What ever the cause of isolation if two groups of organisms of the
same kind are separated from each other they will evolve separately*
MEAN SCORE 2*01 - 2*50

13*

An example (of physical change of individuals within a single area
preventing mating) is the change that occurred in the copulatory
organs of a type of fruit fly that prevented other flies from
mating with it*

Hu

Social custom such as race prejudice that discourages interracial
mating in human societies may result in a kind of isolation*

APPENDIX II

297
DIRECTIONS FOR AREA I ONLY
It Is the purpose of this investigation to discover the
relative importance of the facts Included in the Lecture Sylla­
bus for Biological Solence.
Eaoh fact from Area I of the sylla­
bus is to be evaluated in terms of the contribution w h ic h you
believe it makes toward attainment of the specific o L leotlvea
of Area I.
The speciflo objectives for Area i 'Were taken from
the Study Guide for Biological Science.
The statements to be
evaluated were taken from the syllabus.
Will you rate each
fact or statement
according to the following key 7
Mar k space

1 if you believe that knowledge of the fact
Is essential to attainment ofthe objectives.
Mark space
2 if y o u b elieve that knowledge of the fact
is culte important to attainment of the
objectives.
Mark space 5 if you believe that knowledge of the fact
is of average importance to attainment of
the objectives.
Mark space 4 if y o u believe that knowledge of the fact
is relatively unimportant to attainment of
the objectives.
Mark space 5 if y o u believe that knowledge of the fact
is unrelated to the attainment of the ob­
jectives.

(speciflo objectives of Area I on next page)

298

THE SPECIFIC OBJECTIVES O F A REA I
1.
2.

To understand the objectives of general education.
To understand the plaoe of biological science in a
eneral education program.
o realize the slgnlfloanee of scientific methods in
effective living.

f
1.

Han*a behavior has been guided since the beginning of human
life by two baale requirements, food and reproduction.
2. Primitive man developed forms of cooperation w i t h other men
which resulted in the satisfaction of als basic requirements.
S.
Out of primitive man's cooperation with other m e n grew a
oomplex society which has evolved Into our modern complex
civilisation.
4.
For a n individual to succeed in obtaining his basic require­
ments he must have certain skills that enable him to do some
special task.
5.
Speolal education is necessary to prepare the individual to
do the special tasks that enable h i m to satisfy his basic
requirements w i t h the result that there are schools of busi­
ness, trade schools, schools of medicine, schools of agri­
culture and many others.
6.
Suocess of the individual as a member of society depends
upon other skills and other knowledge (than ability to handle
a special tasks).
He must know how to cooperate, how to
compromise h i s own particular needs a n d desires with those of
others for the common good.
He must understand the workings
of sooiety a n d the function of each individual within it. F o r
this understanding he must know the origin, growth and develop­
ment of society*
He must appreciate the value of different
parts of society, and above all he must learn to think in
terms of the part he can p lay in promoting the welfare of man­
kind.
7.
General education courses teach the skills and knowledge that
are necessary f o r successful group living.
8.
The welfare of the modern world depends In large measure on
the suocess of the general education program in its efforts to
teach people to live together.
9.
Man is a biological organism.
10. Man's primary activities are biological because without food
he could not live and without reproduction human life would
cease to exist.
11. Man competes with other biological organisms for his food and
frequently for his life.
He struggles for his existence Just
as other organisms do.
12. Man has one advantage not enjoyed by his competitors (in the
struggle for existence.
This advantage
is his ability to
learn to a greater extent than any other organism and t o pro­
fit by that learning.

299
13.

14.
15.
16.
17.
18.
19.
20.
21.

22.
23.
24.
25.
26.
27.
28.
29.
30.
31.

Kan can learn how his bod# functions and ho*- hie life 3.a
dependent on matter and energy derived from the earth, from
the sun, and from other living organioirin.
He can learn the
nature of the universal Interrelafcionshipn nnd interdepen- :
denelee of living thlnga and ao bettor oont^ol them for hie
benefit.
He o&n learn the nature a n d habits of his com­
petitors a n d he also must learn that to match successfully
the strength of his competitors he must work with, other
members of his group.
The battle against disease. Insects, and erosion Is no task
for a single Individual.
Rather it is a task requiring the
united effort of all the people.
Biological Science Is designed to give the student an under­
standing of basic biological principles so that he may better
understand his own hature and that of all living things.
With a n understanding of his own nature and that of all
living things the Individual dan live more effectively as
an Individual and as a member of a group.
A solenee is a body of knowledge that ic obtained by means of
the sclentIflo method concerning a n y part of the universe.
In using the scientific method, one makes observations con­
cerning natural phenomenal
The results of these observations concerning natural pheno­
mena
(data) are recorded, olasslflod, and analyzed, and
from this information relationships are determined.
The observations (of natural phenomena) to be useful must
be made w i t h great accuracy.
To lnorease the accuracy (of observations) , various measur­
ing devloes are employed a n d the senses are extended by
means of mioroeoopes,, telescopes, X-ray machines, and many
other Instruments.
Results of the observations (data) are classified In an
orderly manner.
The order (in the process of classifying data) Is developed
in accordance w i t h what man thinks is logical and meaningful.
In the classification of data facts that appear related are
grouped together.
The olasslried data are thought over in the search for re ­
lationships.
It is In the search for relationships that the ability to
think logically a n d brilliantly is of paramount Importance.
The great scientist of the past were great because they
could see relationships not apparent to most men.
Our modern"greats" (in solenoe; qualify In the same manner
(as the greats of the past).
Formulation of an hypothesis is a technique of the scientific
method that aids in the search for relationships or general­
izations.
The hypothesis is a statement of relationships that goes be­
yond known facts.
An hypothesis is made on the basis of too few faots to be
accepted as proved and is no more than a reasonable guess
concerning a possible relationship that seems to exist.

300
The hypothesis
The hypothesis
. vation
of more

52.

25

54 .
55.

56.
57.
58.
59.
40.
41.
42.
45.

45.

46.
47.
48.
49.
60.
51.

52.
55.

must he tested.
lo tested by the collection through obser­
data that relate to the hypotheoio.
The testing of the hypothesis may Include experimentation,
which Is a controlled observation.
In experimentation the emphasis is on the relationship be­
tween oause a n d effeot.
Two similar event3 are observed,
both of w h l o h are exactly alilce except for one factor. Ir
the observed results of the events differ, the difference
must have been due to the variable factor*
An hypothesis that has been tested may still stand as the
best statement of the relationship a bailable or it may be
found to be totally Incorrect, In w h l o h case it is discarded*
If the hypothesis proves Incorrect a revaluation of all the
facts. Including those brought out In the testing, Is made
and a new hypothesis is stated.
As a third alternative the original hypothesis may be partly
correct and In need only of modification.
A theory Is a n hypothesis that ha3 withstood repeated tests,
but which has not been tested sufficiently to be accepted
as true w i t h a very h i g h degree of probability.
A principle Is a relationship or generalization that Is
supported by such a wea l t h of data that its truth Is very
highly probable.
It must be emphasised that no scientific fact, hypothesis,
theory, or prlnolple Is ever proved absolutely true.
Solentlflo truth Is a matter of probability.
The hypothesis, being b a s e d on a few facts only, has the
least chance of being a true statement of relationships.
Furthur observation may easily show that the hypotheels Is
untenable.
The principle (law or doctrine)
has the greatest chanoe
of surviving as a statement of relationohops among natural
phenomena because It Is the result of the accumulation of
years of repeated observations and testa by many scientists.
Because there are so many observations or facts that support
the prlnolple, the possibility that any facto will ever be
discovered that disprove it Is remote.
It should be remembered also that the relationships are
man-made a n d are what seem to be logical explanations of
the observed phenomena of nature.
The scientific method may also be used in everyday life.
Every Individual holds certain things to be true or false,
ood or evil.
hese are opinions (Judgments of good, evil, true, false)
and on the basis of them all people make decisions that
govern the course of their action.
Every Individual must make many decisions during the course
of his life, and the welfare of the individual, hie family,
and soolety as a whole depends on how well these decisions
are made.
The solentlflo method Is useful In arriving at opinions
that guide the course of action.
In terms of the solentlflo method the opinion la the hypothesls and ft person trained In this method will be aware of
the basis (facts) on w h l o h the opinion (hypothesis) has
^

f

301

54.
55.

56

.

57.
58.

59.

60.
61.

been made.
His degree of oonfldenee in the opinion will
vary according to the adequacy of the faote used In its
formulation.
An opinion based on many verified facts w i l l be given more
weight than one without m uch substantiation.
When a n opinion has been accepted it will not be accepted
unconditionally, but further information will be sought tn
ordex* to rev&luate it (the opinion).
In tei'ms of
the scientific method the hypothesis (opinion)
will be tested.
If this further information supports the
original opinion, more confidence oan be placed in it. How­
ever, if it
disagrees w i t h the opinion, all of the infor­
mation must
be re-examined in order to formulate a new one.
A new hypothesis is made to fit a l l of the facts.
A person using the scientific method is open-minded.
A person w h o uses the scientific method open-mlndedly has
the ability to view his opinions in the light of tacts and
is willing to change his opinions in the light of new in­
formation.
Such a p e r s o n also reserves Judgment if after
considering the facts he realises that they are not sufflci*
eat for the formulation of a n opinion.
Many people are faced w i t h the necessity of making a de­
cision without adequate Information to do it scientifically.
They may lack b oth time and facilities for gathering the
needed information; but the decision must be made neverthelc
In cases where a decision must be made without adequate in­
formation the scientifically trained person seeks the advloi
of cow© one whose opinions are based on adequate Informatioi
The ability to recognize a competent authority and the will­
ingness to be guided by his opinions are very Important fac­
tors in living more scientifically.

302
AREA 3 - CHARACTERISTICS C 3MK3N TO A L L LIVING THINGS
It 18 the purpose of this Investigation to dlaoover the re ­
lative Importance of the facts Included In the Lecture Sylla­
bus for Biological Science.
Bach fact is to he evaluated in
terms of the contribution w h l o h you believe it makes toward
the understanding of a fundamental prlnolple of biology.
Please interpret the word "understanding11 within the limits
you believe to be Imposed by the objectives of general ed­
ucation end the speoiflo objectives of the area In w h l o h the
principle occurs.
The principles were taken from the Study
Guide for Biological Science.
You w ill find the. principles
from each area In the study guide followed b y facts taken
from corresponding areas o f the syllabus.
Hill y o u rate
each fact according to the following keyt
Hark epacc 1 if y o u believe that knowledge of the fact
I 0 essential to a n understanding of the
prlnolple.
Nark space 2 If you believe that knowledge of the fact
It aulte important to a n understanding of
the principle.
Hark space 3 If y o u believe that knowledge of the fact
Is of average importance to an understand­
ing of the principle.
Mark space 4 If y o u believe that knowledge of the fact
I* w j a t i w e i w unimportant to an understand­
ing'oftheprinoiple.
hark space 5 If you believe that knowledge of the fact
I0 unrelated to a n understanding of the
principle.
THE SPECIFIC OBJECTIVES O P AREA 3
1.
To lea r n the characteristics of living things.
2
To understand the fundamental organisation of plants
a n d animals.
3.
To understand the basic significance of respiration
to living things.

.

PRINCIPLE 1
Protoplasm is a conoequenoe of the organisation of matter
and energy.
X.
2.

3.
4.

Living things assimilate a n d utilise materials and energy.
Living things take Into their bodies non-living materials
that are synthesised chemically Into living protoplasm or
oxidised to release energy that Is used In the living pro* ■
cess.
Life can be maintained only when a constant stream of ma ­
terials and energy is passing through the liv i n g organism.
All of the substances in protoplasm are combined Into a
complex organisation in w n l c h chemical and physical process­
es occur that result in life.

303
PRINCIPLE II
The bodies of plants a n d animals are composed of oells or
the products of oells.
1.
2.
3.

4.

5.
6.
7.
8.

Each Individual organism Is made of the same material, which
Is a complex kind of fluid substance known a s protoplasm.
Protoplasm usually takes the form of small bloo k s or spheres
oalled cells.
In the smallest organisms the entire structure Is composed
of one cell, while In the larger more oomplex l i v i n g things
ouch as man the oells are multiplied millions of times to
form the complete individual.
Complex organisms a re made of many millions of oells which
are differentiated Into various kinds.
In oomplex organ­
isms the oells are grouped on the basis of structure and
funotlon into tissues a n d these are combined to f o rm organs.
The organs a r e united into systems.
Groups of cells of similar structure whloh perform special­
ised functions are oalled tissues.
The bodies of man and bther oomplex animals a s well as the
bodies of vascular plants a r e composed of several kinds of
tissues.
Organs In b o t h plants a n d animals a r e oomposed of tissues
that work together to per f o r m a specific funotlon in main­
taining Ilfs.
Organs that w o r k together to accomplish one of the primary
functions of the Individual compose the organ systems.

PRINCIPLE III
Life processes are the activities of protoplasm.
1.
2.
3.
4.
5.
6.
7.
8.
9.

Each individual Is mads of protoplasm organised Into cells.
Every process or funotlon of a liv i n g organism, such as
digestion, movement, seeing or th i n k i n g is the resu lt of
the action of oells.
The protoplasm of w h l o h cells are mads Is from 60 to 90 per
cent water.
The rest is composed of
proteins, carbohydrates,
fats, minerals and ensymes In varying proportions.
All of the substances In protoplasm are combined Into a oom­
p l e x organisation In w h l o h chemical and physical processes
ooour that result In life.
Living things assimilate a n d utilise
materials a n d energy.
Living things grow.
Living things reproduce.
Living things a r e adapted to their environment.
Living things move.

PRINCIPLE IV
Living things have a common structural pattern.
1.
2.

Superficially no common pattern is apparent, but the common
pattern Is there.
Each individual is made of the same material, whloh.Is a
complex kind of fluid substance known as protoplasm.

3.
4.
£>.
6.
?.
6.
9.
10.
11.
IS.
13.
14.
15.
16.
17.
16.
19.

SO.
£1.

In living organisms protoplasm usually takes the f or m of
small blocks or spheres oalled oells.
Tho cell is the unit of struoture and funotlon of a l l living
things.
Svery process or funotlon of a living organism, suoh as di­
gestion, movement, seeing or thinking is the result of the
notion of cells.
A cell is made of protoplasm a n d h a s two major parts, the
nucleus and the cytoplasm.
The nucleus is usually a spherical struoture a n d looated
near the center of the oell a n d limited by a thin, proto­
plasmic membrane known a s the nuolear membrane.
Inside of the nuolear membrane the nucleus is filled with
another kind of protoplasm oalled nuoleoplasm.
Nucleoplasm is a thin, watery liquid In w h loh Is immersed a
loose Irregular network of ohromatln granules.
A large spherical body, the nuoleolue, is a lso found in the
nucleus.
The remainder of the cell surrounding the nucleus is the
cytoplasm.
A thin, tough protoplasmlo membrane, the oell membrane,
surrounds the entire oell.
between the oell membrane a n d the nuolear membrane is the
watery cytoplasm whloh oontalfts a variety of structures
suoh as vaouoles, food granules, oell products a n d wastes.
Plant oells have a wall made of cellulose outside of the
oell membrane.
Groups of oells of similar struoture whloh perform special­
ised function are oalled tissues.
The bodies of man and other oomplex animals as well as the
bodies of vascular plants, are composed of several kinds of
tissues.
Epithelial tissue is thin a n d sheet-like a n d serves to cover
turfaces and to line oavlties.
The outer layer of the skin w h i c h covers the body Is an epi­
thelium, as are the linings of the digestive tract, the a b ­
dominal cavity, a n d the onest cavity.
C v e r y cavity, duct a n d v e s s e l in the body Is lined with epi­
thelial tissue.
Connective a n d supporting tissue holds the parts of the body
togethex* and gives support.
Several types of tissue are oonsldered as connective and
supporting tissue.
*'hey a r e white fiberous tissue, elastic
tissue, fatty or adipose tissue, cartilage and bone.
The connecting and supporting tissues a r e characterised
by the presence of cells plus a non-cellular substance known
as matrix that lies outside*the oells.
Kuscle tissue contracts a n d in so doi n g moves body parts.
There are three kinds of muscle: striated or skeletal mus­
cle, smooth or visceral muscle, and heart or oaridao mueole*
Striated muscle makes up the nr as of the body and moves the
skeletal parts.
S t r i a t e d muscle la composed of elongated oells w i t h many
nuclei and w i t h alternating light a n d dark bands across the
cells.

.

22

23.
24.
26.
26.

305
£?.
29.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.

43.
49.
50.

51.
32.
53.

The light a n d dark bands (striations) on skeletal muscle
is thought to be related to the contracting power of the
tissue and gives it its nave.
Smooth muscle is so oalled because it lacks the striations
of skeletnl muscle.
,;
Smooth muscle oells are spindle-shaped and contain but one
nucleus.
In smooth mueole the spindle-shaped oells lie parallel a n d
form sheets of tissue that fora the walls of various tabes
and duota of the body.
The intestine contains two layers of smooth mueole which
contract a n d move the food along.
Cardlao muscle is found in the heart.
Cardiac muscle is made of branohlng. striated cells.
The cardlao muscle oells contract a n d relax rhythmically
to produce the pumping a c t i o n so essential to the funotlon
of the heart. •
Nerve tissue is made up of nerve cells (neurons).
Neurons have a rounded or triangular oell body to which are
attached fibers. the dendrites and axons.
The dendrites a n d axons interconnect parts of the body a nd
oonduot nerve lnqpulses.
Bundles of nerve fibers make up the nerves.
Blood is a fluid tissue a n d consist of a liquid plasma and
floating oellular elements.
The cells of blood Include the red oells and the white cells.
Blood tissue transports materials throughout the body and
aids in disease resistance.
Kerlstem tissue consists of small, thin-walled oells which
have the ability to divide repeatedly.
Morlatem tissue is found a t the tips of stems and roots
and in vascular bundles where growth takes place.
The cells of merlstem tissue differentiate or change into
all of the other tissues of the plant body.
Epidermal tissue of plants is similar to epithelial tissue
of animals in that it covers surfaces.
Epidermal tissue cells are usually small a n d arranged in
a single layer.
In leaf epidermis the outer oell walls are thick and oovei*ed with a waxy layer whloh reduces water evaporation, while
in root epidermis they are thin-walled and permit the ab ­
sorption of water.
borne epidermal oells of roots have slender projections that
extend between the soil particles.
These are the root hairs.
Parenchyma tissue is made of large, thin-walled, unspeolalised cells.
homo parenchyma oells are colorless and used mainly for stor­
age, while others, in leaves and near the surface of green
atoms, contain ohloroplast and are used mainly for food manu­
facture.
Two kinds of supporting tissue in plants are fibers and wood.
Fibers are extremely thlok-walled. elongated oells with point­
ed ends.
When nature they oontaln no protoplasm.
The overlaping of the pointed ends of the fiber oells give
&reat flexibility and strength to the tissue.

306
AREA 4 - T R A N S F O R M A T I O N

OF

SOLAR ENERGY?

PHOTOSYNTHESIS

It Is the purpose of this Investigation to discover the re­
lative Importance of the facts included in the Lecture Sylla­
bus for Biological Science.
E ach fact is to bo evaluated in
terms of the contribution w h i c h you believe It makes toward
the understanding of a fundamental principle of biology.
Please interpret the word ‘’understanding* within the limits
you believe to be imposed by the objectives of general ed­
ucation and the specific objectives of the area in which
the prlnolple ooours.
The principles were taken from the
Study Guide for Biological Soienoe,
You will find the prlnblples from e a o h a rea in the study guide followed by facts
taken from corresponding areas of the syllabus.
Will you
rate eaoh faot according to the following key ?
Mark space 1 if you believe th«t knowledge of the faot
is essential to an understanding of the
prlnolple,
Mark Space 2 if y o u believe that knowledge of the fact
is quite important to a n understanding of
the prlnolple.
Mark space 3 if y o u believe that knowledge of fchc fact
is of average Importance? to an understand­
ing of the principle.
Mark space 4 If you believe that knowledge of
'.o ’
*■« EglfttlJglY unimportant to an un
-r:;•;>
lng of the prlnolple.
Mark space 3 if y o u believe that knowledge of the fact
is unrelated to a n understanding of the
principle.
THE SPECIFIC OBJECTIVES O F AREA 4
1.
To gain some understanding of the nature of natter
and energy.
2.
To study the energy relationships In living organ­
isms,
3. To understand photosynthesis and to realize the
significance of this process to all living things.
4.
To study the physical basis for the movement of water
and d i s solved materials in plants.
PRINCIPLE I
Matter is the substance of the universe,
1.
2.
3.

Matter
occupies space, has inertia, and attractc other
matter w i t h a force called gravity.
It can be seen,
felt, tasted and smelled.
Matter is composed of atoms,
The idea that matter is composed of atoms was ooncelved
by the ancient Greeks 2000 years ago.
(oontinued)

307
4.

5.
6.
7.
8.

There are thousands of d i f ferent k ind a of matter, but
this does n o t m e a n that there are thousands of different
kinds of atoms, for a t o m s can combine and form substances
that have c h a r a c t e r i s t i c s entirely dif f e r e n t f rom those
of the a t o m s c o m p o s i n g them.
There are 9 2 k i nds of a t o m s in nat u r e and some unstable
atoms p r o d u c e d in the laboratory, e a c h of w h i c h is called
a oheml o a l element.
The c o m b i n a t i o n s of these elements (atoms) p r o d u ce all
of the k i n d s of m a t t e r that make up the universe.
This m a t t e r (of the universe) Is u s u a l l y In the form of
molecules, w h i c h Is the n a m e giv e n to the p a r t i o l e form­
ed by the u n i o n of two o r more atoms.
E x a mples of a t o m s or e l e m e n t s are carbon, hydrogen, oxyen a n d nitrogen.
xamples of m o l e o u l e s a r e water, c a r b o n dioxide, sugar,
lard a n d gelatin.
A m o l ec u l e of w a t e r Is f o r m e d wh*$n two atoms of h y d r o g e n
combine w i t h one a t o m of oxygen.
This r e a c t i o n does not
o c cur q u i t e a s simply a s this, but for i l l u s t r a tion can
be written:
2H+0-*Hg0
If one a t o m of o a r b o n u n i t e s w i t h two a t o m s of oxygen the
result Is a m o l e c u l e of c a r b o n dioxide.
0 -l-Og -♦ C O g
Moleoule s o a n a l s o be c o m b i n e d to f orm larger molecules.
F o r example, 6 m o l e o u l e s of car b o n dioxide (COg) o an be
united w i t h 6 m o l e c u l e s of water(HgO) to form a molecule
of glucose (CgHigOe)*
In this r e a c t i o n there are 6 more
mo l e oul e s of o x y g e n (Og) t han are r e q u i r e d in the glu­
cose molecule, so t h e y a r e g i ven off a s m o l e c u l a r oxygon.
The e q u a t i o n a s w r i t t e n in chemical shorthand is:
6 C O g -4® 6 H g O —
C q H t gOg * O O g
carbon d i o x i d e
water
glucose
oxygen
Fat, a n o t h e r k i n d of food. Is a l s o for m e d by the combin­
a t i o n of carbon, h y d r o g e n a n d oxygen.
Protein, a n o t h e r food, Is formed b y the c o m b i n a t ion of
carbon, hygrogen, oxygen, nitrogen, a n d fr e q u e n t ly other
elements s u c h a s sulfur, p h o s p h o r u s a n d o c c a s i o n ally
m a g n e s i u m a n d Iron.
Vitamins a l s o c o n t a i n carbon, hydrogen, a n d oxygen.

f

10.

11.

12.

13.
14.

13.

PRINCIPLE II
The u l t i m a t e source of e n e r g y a v a i l a b l e to l i v i n g
organisms w i t h i n our p l a n e t a r y s y s t e m Is the r a d i a t i o n
fr o m the sun.
1.
2.

Stored c h e m i c a l e g e r g y Is the souroe of all e n e r g y used
by livi n g thin g s
G r een p l a n t s h ave the a b i l i t y to take the light energy of
the sun a n d con v e r t it into chemical energy.
(continued)

308
3.

The energy that is used by living things to carry on the
process of life is chemioal energy stored in molecules of
carbohydrates, fats and proteins.
The ultimate course of
this stored energy is sunlight, w h i c h is changed from light
energy to stored or potential ohemioal energy,

4.

Only green plants can store energy (from the sun) Sn this
fashion, so the source of a l l energy used by living things
is the green plant.

5.

Sunlight consist of light waves of different lengths which
can be separated by passing through a priom tc form a minature rainbow consisting of the following colora: red, orange,
yellow, green, blue, indigo and violet,
The light waves whi o h produce the red, blue, and violet re*
glone of the spectrum are absorbed by the chlorophyll in
the palisade and spongy cello, and the energy is used in
combination w i t h water a n d carbon dioxide to produce glu­
cose.

6.

PRINCIPLE III
Life is a result of the organization of matter and energy
in a dynamic equilibrium that oan be maintained only by
the oonstant utilization of matter and energy,
1,
2,

S.
4,
5,
6,

Within the organism, matter and energy become a part of a
complex. Integrated meohanism that lives,
The organization of the matter and energy is stable so
long as life continues, but it is a dynamic sort of organ­
ization in whi c h both matter and energy are continually
being utilized,
Life ceases If non-living materials and energy are not
constantly b e i n g fed into the living protoplasm,
The stored chemical energy in organio foods ie the eource
of all energy used by livi n g things.
To use (this) stored energy, living things break the
bonds that h o l d the a t o m ’' of the zaolocsftlft together and
the energy is released,
Oxygen Is necessary f o r this process (of releasing energy
from stored food) w h ich explains why living organisms need
a oonstant supply(of oxygen).
The equation for this energy
releasing reaction is:
c 6 h 12°6 “* 6 °2 — ^ Energy h 6C02 4- 6 HgO

PRINCIPLE IV
Energy and m a t t e r .are neither created nor destroyed in life
processes,
1.

In order to maintain life, non-living matter must be taken
from the environment a n d built into the structure of the

body.

,

(oontinuod)

309
2. Energy must also be taken from tho environment and used
to carry on the living functions.
3. Within the organism matter and energy become a part of a
complex, integrated mechanism that lives.
4. The organization of the matter and energy is atable so
long as life continues, but is a dynamic sort of organiza­
tion in which both matter and energy are continually being
utilized.
5. Energy appears in several forms and can bo changed from one
form to another.
6. In all {of these) forms of energy one type of motion replaces
another.
7. The energy of motion is oalled kinetic energy.
8. Energy c m be stored.
9. Stored energy is oalled potential energy.
10. Stored chemical energy is the source of all energy uced by
living things.
PRINCIPLE V
In photosynthesis radiant energy is transformed to chemioal
energy.
1.
2.

3.
4.

5.

6.

7.

Photosynthesis is the prdoess whereby water, oarbon dioxide,
and light energy are combined through the aid of chlorophyll
to produce carbohydrate food.
Chlorophyll in a living cell is essential in this reaction
(photosynthesis) because it alone oan make use of the ra­
diant energy of the sun to separate certain of the carbon
atoms from the oxygen in the carbon dioxide molecule; to
separate certain of the hydrogen atoms from the water mole­
cule, and to recombine these atoms to form glucose, a simp­
le sugar.
The Chlorophyll probably acts as a catalyst in this react­
ion (photosynthesis), but the details of the process are
still obscure.
(In the photosynthesis reaction) six molecules of carbon
dioxide combine w i t h six molecules of water to produce one
moleoule of glucose.
The equation written In chemical
shorthand is:
6 COg -f- 6 Hg© + (energy) —
C 6H 1S°6 -*■ 6 °2
Six moleoules of oxygen are not utilized in the process
(of photosynthesis) a n d diffuse to the atmosphere.
This
is the primary source of oxygen for cellular respiration
in animals and plants.
Photosynthesis serves not only as the source cf energyyielding food for all living things but also supplies the
oxygen which is necessary to release the energy so that
it oan be used by living organisms.
The glucose formed within the plant cell (by photosynthesis)
may be oxidized (oomblned with free oxygen), and the chemi­
cal energy w h ich is released is used by the plant.
(continued)

310
8#

The energy used by plants cannot bo taken directly from
the sunlight but must be released by oxidation frcm a food
molecule Just as in animals.

PRINCIPLE VI
Only green plants, those containing chlorophyll,
solar energy for the manufacture of foods.
1.
2.
3.

4.

5.

6.
7.
8.

9.

10.
11.

12.
13.
14.
15.

can utilise

Green plants have the ability to take the light energy of
the sun a nd convert It into chemioal energy.
They(green plants) use oarbon dioxide and water and combine
them into molecules of gluoose.
Within the gluoose molecule is the energy which has been
converted from light energy into chemical energy.
The
equation for this process le:
6 COg-f' 6HgO ■+• Energy —
^6^i2°6
® °2
The ultimate souroe of stored energy T i n food) is sun­
light which is changed from light energy to etorod or
potential chemical energy.
Only green plants can store
energy in this fashion,so the source of all energy used
by living things le the green plant.
The green plant is the souroe of all energy-yielding
foods and also of most of the foods that do not contain
energy.
Water and some minerals may be obtained from
nonplant souroes.
The more common flowering plants are composed of roots,
steras, leaves, flowers and fruits.
The roots extend into the ground where thsy serve to anch­
or the plant and to absorb and conduct water and inorganic
minerals.
The root may be composed of a single long process that ex­
tends downward into the ground from whloh smaller secondary
prooesses extend laterally.
This type is called the tap
root system.
Another type (of root system) is the fibrous root system
in which there is no main process, but rather many, of
similar length and thickness, that extend in the soil
downward and laterally in all directions.
A single root le oomposed of mapy oells.
The outside ooverlng of the root is the epidermis which
is composed of flattened, rectangular cells, each of
which may have a protoplasmic projection, the root hair,
extending between the soil particles.
Beneath the epidermis(of the root) le the cortex which
is composed of parenchyma cells.
In
thecenter of the root is the vascular tissue.
In
theoentral portion ofthe root is the xylem tissue and
between the xylem and the oortex lies the phloem (tissue).
At
the tip of the root are found zneristem cello, which dlvide and cause growth of the root.
,___

311
16.
17.
18.
19.
80.
21.
22.
25.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.

The root cap, covering the extrema tip of the root,
protects the. growing tissue as the root rushes into
the soil.
The cells of the root cap are destroyed and sloughed off
during root growth and must constantly bo replaced from
the merlstem tissue.
The stems hold the plant upright and support the branches
and leaves.
The stems also conduct water, minerals and other foods.
The stem has an outer single layer of cells again oalled
the epidermis.
Beneath thls/the epidermis of the stem) Is the cortex made
of parenchyma cells.
Inside of the cortex(of the stem) is the central cylinder
of vascular tissue.
Inside the circle of vascular bundles(of the stem) is a
central core of pith.
The pith (of the stem) is also composed of parenchyma cells.
Bach vasoular bundle has three parts: the phloem, mArlstem
tissue, a n d xylem.
The phloem lies on the outside of the vasoular bundle
near the cortex.
The xylem lies on the Inner side near the pith.
The merlstem tissue(of the stem) Is between the phloem
and the xylem.
The leaves are the food-making organs of the plant.
The leaf Is usually of two parte, the leaf stem and the
blade.
The leaf stem supports the blade and contains conducting
tissue.
The blade Is usually broad, flat and thin.
A waxy outlcle covers the surface of the leaf, beneath
which Is a single layer of cells, the epidermis.
Inside the leaf are two cell layers, the palisade layer
and the spongy layer.
The cells of both layers (palisade and spongy layers) con­
tain chloroplast.
The palisade layer is made of Irregular and somewhat el­
ongated cells that stand more or loss close together.
The spongy cells are more or less Irregular In shape and
have a i r spaces between them which are Interconnected
throughout the leaf.
On both upper and lower surfaces of most leaves are tiny
openings, the stomates.
These(the stomates) permit air from the atmosphere to en­
ter the air spaces of the leaf.
The stomates are usually more numerous on the under sur­
face of the leaf than on the upper surface.
£aoh at ornate is surrounded by guard oells which regulate
the size of the opening.
Veins extending throughout the leaf, crc extensions of
the vasoular bundles of the roots, stems, branches and
leaf stems.

312
PRINCIPLE VII

1.
2.
3.
4.
5.

6.
?•
8.
9.

10.
11.

12.
13.

14.
lb.

Diffusion Is the basic mechanism of transport operating
In the physical activities of organisms aae!3tod by the
Movement of fluids.
Plants absorb water from the soil by means of the root
hairs.
The roots and attached root hairs lie between soil parti­
cles which are immersed in water.
The water enters the oells of the root by a form of diffus­
ion known as osmosis.
Diffusion is a process whereby one substance becomes spread
throughout another substance.
A n example of diffusion is sugar and water.
When sugar is
added to w a t e r the sugar becomes dissolved and In so doing
it gradually spreads throughout the water until it is equal­
ly distributed.
The force w h i c h causes the sugar to spread Is a moleeular
force.
Moleoules are subject to two opposing forces.
Attraction
tends to hold them together and their motion causes them
to separate.
This separating foroe(aotlng on moleoules) is heat energy.
When sugar(for example) is dry, the attractive or cohesive
force of the moleoules on each other is greater than the
dispersing foroe and they cling together in crystals of
sugar.
When the crystals (of sugar) are moistened with water,
the bonds that hold the moleoules together are loosened
and they separate.
(When the molecules separate) each molecule moves In a
straight line away from
its neighboring molecules
until
it is stopped, by collision either with another sugar
molecule, w i t h the wall of the container, with the surface
of the liquid, or with the water molecules.
Whenever collision occurs the molecule moves in another
direction, in a straight line again, until it bumps into
something else.
Because the moleoules move in a straight line until stop­
ped and then ..immediately start off in another straight
line, it is obvious that the moleoules will tend to nova
away from the area of greater concentration to one of
lesser oonoentratlon.
Repeated collisions in congested
areas prevent any great
movement toward this aroa
but in
sparsely occupied areas
progress Is not impeded.
Finally the molecules fill all of the available space and
become equally distributed among the water molecules.
Osmosis is diffusion of water through a membrane so con­
structed that it permits moleoules of water to pass throu­
gh but does not permit moleoules of a dissolved substance
tq pass through.
Such a membrane is differentially perme­
able.
(Continued)

313
16.

17.

16.

19.

20

.

21.

Xf a vessel Is so constructed that a differenti a l l y per­
meable membrane separates a solution of pure writer and
a solution of sugar and water, the water lroleculeti can
move both ways through the membrane but the sugar mole­
cules cannot because the membrane permits the water
molecules to move through but prevents the sugar mole­
oules from doing the same.
The movement of the water molecules is entirely inde­
pendent of the sugar molecules and they move in accordance
with the laws of diffusion: that is, they move from an
area of greater concentration- of water to one of lesser
concentration of water.
(In an osmotlo system) the water molecules are more concen­
trated for any given spaoe within the pure water side than
they are on the sugar side of the membrane.
This is due
to the presenoe of sugar moleoules which by occupying
spaoe among the water molecules cause them to be farther
apart than they would be in a pure solution.
Hence, the water moves by diffusion from the pure water
side to the sugar solution side of the membrane.
The sugar molecules w o uld move by diffusion through the
membrane to the pure water side likewise, but they are
prevented from doing so by the membrane.
Osmosis plays a n Important part in the absorption and
transport of water by a plant.
The roots (of plants) with their root hairs lie between
particles of soil immersed in water.
The protoplasm within the epidermal cells. Including
the root hairs, contains more substances in solution,
such a s sugars and organic acids, than the water in the
Boll(ln w h i c h the root hairs are immersed).
The cell membrane (of the root hair cells) acts as a
differentially permeable membrane which permits the f.
flow of water through it, but does not permit the dis­
solved substances of the cell to flow out.
The result
is that the water diffuses into the cell by osmosis
through the cell membrane.
The water (that passes through the root hair cell membrane)
moves first into the root hair cells and other epidermal
cells that surround the root.
This increases the water
concentration of these cells over that of the cells next
to them inside of the rotft. Osmosis again occurs and
water moves through the epidermal cells into these adjacent
cells.
A repltition of this process of osmosis from cell to cell
toward the center of the root brings the water eventually
to the xylem oells of the vasoular bundle in the center
of the root.
The water is conducted upward by capillarity, root pressure,
and other forces through the xylem of the root to the xylem'
of the stem, through the xylem of the stem, branches, and
leaf stems until it eventually reaches the leaves.

.

22

26.

24.

25.

26.

27.

31U
28.
29.

30.
31.

32.
33.
34.
36.
36.

The water evaporates frori ths surface of She cpongy and
palisade cells of the 2e af.
This evaporation is known as
transpiration.
When transpiration occurs from the surface of the palisade
and spongy cells, the water within these cells diffuses
to the surface and replaces that lost by evaporation, ttith
the result that the concentration of water within the cell
is decreased; below that in adjacent cells not exposed to
the air.
Osmosis results and the water moves frou these
adjacent cells into the cells lining the air spaces.
This
reduces the water content of these cells, which in turn
oauses w a t e r to move by osmosis from the cells next in
line.
This la repeated from cell to cell starting with
the oells lining the a i r spaces and ending with the cells
surrounding the xylem of the veins.
The cells surrounding the xylem of the vein(of the leaf)
receive water from the xylem.
The xy$em of the v e i n s (of the leaf) is connected directly
with that of the leaf-stern which le connected \Vith th©'
xflSJn of the stem.
The stem xylem l a connected, wilh the
root xylem.
Movement of the water upward through the £ylem ducts is
i’due in part to capillarity, root pressure, and other for­
ces not fully understood.
Minerals that are in Solution in the soil water move by
diffusion into the epidermal cells of the roots and then
into the xylem.
Minerals are oonduoted upward into the leaves by the
xylem of the roots, stems, leaf-stems, and veins.
In the leaves minerals in solution move from the veins
into the palisade and spongy cells by diffusion.
Plants receive oarbon dioxide from the air, which diffuses
into the leaves through the stomates and then into the
palisade and spongy cells.

PRINCIPLE VIII
The synthesis of fats and proteins and carbohydrates other
than gluoose is a sequel to photosynthesis which makes
matter and energy available to living things.
1.
2.
3.

4.

The gluoose formed within the plant cell(by photosynthesis)
may be oxidized(combined w i t h free oxygon), and the ohemloal energy w h i c h is released is used by the plant.
The energy used by plants cannot be token directly from
the sunlight but must be released by oxidation from a food
molecule Just as in animals.
The glucose may also be changed directly Into double sugar
or starch and stored in the leaver or It may be trans­
ported in the phloem to some other part of the plant and
there stored as sugar or starch.
(The gluoose) may also be changed Into fat, which may be
stored.
(continued)

315
5,
6.

Finally other chemical elements may bs added &r.d the
glucose ohanged Into protein, which la uoed to build more
protoplasm for the plant cells or stored.
in normal growth and development oJT plants food Is stor­
ed In roots, stems, leaves and fruits.

316
AREA 5 - UTILIZATION
UNIT

OF MATTER AND ENERGY

1 - Foods and Digestion

It Is the purpose of this Investigation to discover the re­
lative Importance of the facts Included In the Lecture Sylla­
bus for Biological Science.
Each fact Is to be evaluated In
terms of the contribution which you believe it makes toward
the understanding of a fundamental principle of biology.
Please Interpret the word "understanding" within the limits
you believe to be Imposed by the objectives of general ed­
ucation and the specific objectives of the area In whloh
the principle occurs.
The principles were taken from the
Study Guide for Biological Science.
You will find the prin­
ciples from eaoh area In the study guide followed by facts
taken from corresponding areas of the syllabus.
Will you
rate eaoh fact according to the following key ?
Mark spaoe 1 if you believe that knowledge of the fact
Is essential to a n understanding of the
prinoiple.
Mark space
2 If you believe that kna lcd> n of V f-ct
is quite Important to rn u n d o r r ; t*'n a n r o f
the principle.
Mark space 3 If you believe that knowledge of the fact
Is of average Importance to an understand­
ing of the principle.
Mark spaoe 4 If you believe that knowledge of t h o fact
Is relatively unlraoortant to an understand­
ing of the principle.”
Mark Space
5 If you believe that knowledge of the-fact
is unrelated to an understanding of the
prInc ipie.
THE SPECIFIC OBJECTIVES OF AREA 5, UNIT 1
1.
To classify energy-containing foods as to their
eneral characteristics and their specific actions,
o realize the significance of vitamins and the
importance of water and mineral salts in the diet.
S. To understand the baslo significance of the digestive
prooesses.

f

PRINCIPLE I
Food is the only form In which matter can be utilized
by living things.
1.
2.

Food is any material that can be used by living things
to maintain the normal state of protoplasm.
Some foods furnish energy and some foods provide build­
ing materials, while others aid In different ways In the
metabolism of the body.

317
3„
4.
5.
6.
7.
8.

9.
10.
11.
12.
13.
14.
13.

16.
17.

18.
19.
20.
21.

Foods Include the organic foods- carbohydrates, fats,
proteins and vitamins- and the Inorganic foods— minerals,
water, oxygen and oarbon dioxide.
Common foods such as meat, fruits and vegetables are mix­
tures of the baslo food substances.
The carbohydrates supply living things with their main
source of energy.
Carbohydrates include sugars, starches, glycogens and
celluloses.
Chemically the carbohydrates are all fundamentally alike
in that they are all composed of the three elements- car­
bon, hydrogen and oxygen.
There are usuftllj^Cor multiples of six) moleoules of oar­
bon in the carbohydrate moleoule and the hydrogen and oxy­
gen are usually present in the same proportion as in water,
that is, 2 parts of hydrogen to 1 of oxygen (H©0).
The formula for glucose (CgHjoOg), which is a simple sugar,
illustrates this molecular relationship(in the carbohydrate
moleo u l e ).
There are three classes of carbohydrates- simple sugars,
double sugars, a n d complex carbohydrates.
Gluoose, fruotose and galaotose are simple sugars and have
the formula C6H12°6*
Maltose, lactose and suorose or cane sugar are double su­
gars and have the formula Ci£H22°ii•
Starch, glycogen and oellulose are complex carbohydrates
and have the formula (C«H1o 05 ) n e
Two moleoules of a simple sugar can combine to form one
moleoule of a double sugar.
In this process one molecule
of water is released.
When two molecules of a simple sugar combine to form one
moleoule of a double sugar the reaotlon can be written
in chemioal shorthand as follows:
eSmpfo6
+
^
‘’iluSfe11 *
liter
sugar
sugar
sugar
By combining many simple sugar molecules in the same
fashion complex moleoules of starch, glycogen or oellu­
lose oan be formed.
The *nN in the formula for a complex carbohydrate (CgH100 5 )n
represents a high number (from 20 to 300) of simple
sugar moleoules that have combined to form the complex
carbohydrate•
Fats are another good souroe of energy for living organ­
isms.
Fats are oontalned in quantities in such foods as vege­
table/oils, nuts, butter, cream, lard, bacon and other
fatty meats.
The elements oarbon, hydrogen and oxygen rake up the fat
moleoule, but the hydrogen and oxygen are not in the ratio
of HoO as in carbohydrates.
In fats there is less oxygen in proportion to the hydrogen
than in the oase of oarbohydrates.

318
22.
25.
24.

25*
26.
27.
26.
29.
50.
51.
52.
55.
54.
56.
56.
57.
58 i.
59.
40.
41.
42.
45.
44.

Because fats are less oxidised than carbohydratee, they
contain more energy per unit of weight.
Fate are characterised aleo by b41ng solu/ble in alcohol
and ether and they feel greasy to the touch.
Fats are formed by the union of fatty a d d s and glycerol,
which are relatively elmple molecules that have the buildlng-blook relationship to complex fat molecules that the
simple sugar molecules, such as glucose or fructose have
to the complex carbohydrates.
Proteins are used as building materials for the protoplasm
of the body but may also be used as a source of energy.
Foods high in protein content are lean meats, eggs, gela­
tin, cheese and nuts.
Proteins contain the chemical element, nitrogen as well
as carbon, hydrogen and oxygen.
Phosphorus and sulfur are often contained in the mole­
oules (of protein).
The moleoules (of proteins) are formed by the union of
simpler moleoules called amino acids.
The amino aoids have the same relationship to protein
moleoules that the simple sugars have to complex carbo­
hydrates and that fatty aoids and glycerol have to fats.
Amino aoida combine in Infinite ways to form the large
and complex protein moleoules that make up the major
proportion of living protoplasm.
Amino aoids are recognised chemically by the grouping
together of nitrogen and hydrogen as NHU.
NH2 Is known as the amino group.
There are about twenty-three amino acids known.
The amino aoids oomblne In different proportions to form
many different kinds of proteins found in living things.
In man the proteins in the cells of different organs vary
one from another.
There are also oertaln differences apparent in proteins
of different Individuals.
The proteins found in dlfferat species of animals and
plants differ greatly.
Vitamins are organic compounds required of living organ­
isms In very minute amounts, but whose absence causes nu­
tritive deficiency diseases.
The vitamins were first named alphabetically A, B, C, D,
E and K, but these names are gradually being replaced by
the ohemloal name of the substance as these become known.
Several of the vitamins have been synthesized in the
laboratory and manufactured for commercial sale.
With the exception of vitamin D, the primary source of
vitamins in nature Is plants.
Vitamin A is found In animal products such as egg yolk,
butter, and ood-liver oil.
Certain pigmented plants such as carrots, squash, sweet
potato.and yellow corn contain a yellow pigment, carotene,
.which oan be transformed by some animals Into vitamin A.

319
45.
46.
47.
48„
49.
60.
51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
66.
69.
70.
71.
72.

Vitamin A is essential for normal growth, for the main­
tenance of healthy epithelial tissues, and for the pre­
vention of night blindness.
Vitamin B is found in many plants, particularly in bran,
wheat embryo and yeast.
Vitamin B is a complex of several chemical substances.
Milk, oysters and lean pork are animal sources of vitamin B.
Vitamin B Is necessary for normal metabolism, for the pre­
vention of pellagra and to maintain healthy nerves.
Vitamin B causes root growth In plants.
The effects of a deficiency of vitamin B on the nervous
sydtem vary from mild nervous disorders to the more severe
symptoms found in beriberi.
Vitamin G is also known as ascorblo acid.
Vitamin C is present In fresh fruits, particularly citrus
fruits.
In the absence of vitamin C, scurvy develops.
Scurvy is a degenerative disease affooting many parts.
Including the teeth and bones.
Vitamin D Is known as calolferol.
Vitamin D is abundant in the liver oils of various fish,
particularly cod and halibut.
Irradiation of milk, yeast and certain plant and animal
fats will produce calciferol.
Human beings can synthesise vitamin D If the skin is ex­
posed to direct sunlight.
Vitamin D is necessary for the absorption of calcium and
phosphate from the intestine.
The absence of vitamin D results in a bone disease known
as rickets.
Vitamin E Is known chemically as tocopherol.
Vitamin E le probably essential for the maintenance of
normal reproductive activities.
Vitamin E is found In wheat germ oil and In germ oil of
other grains.
The normal diet contains ample quantities of vitamin E,
Vitamin K is essential for the normal clotting of blood.
Vitamin K is used to reduce bl&edlng in modern surgery.
Vitamin K is formed in the intestine by the action of
baoterla on food residues and consequently Is not needed
as part of the diet.
Water and minerals are the essential inorganic minerals.
Life as we know it would be impossible without water.
The minerals necessary for organisms Include oalclum,
magnesium, potassium, and sodium In combination with
ohloride, phosphate and carbonate.
Small amounts of iron, cupper, cobalt. Iodine, fluorine,
manganese, and sine are also neoessary(ln the diet).

320

PRINCIPLE II
The chemical energy of organic food le the only form In
whloh energy le utilize hie by the metabolic activities
of o r g a n i s m s .
1.
2.
Z,
4.
5.
6.

Chemioal energy oan be stored In moleoules.
Green plants have the ability to take the light energy
of the sun and convert It into ohemlcal energy.
Green plants use carbon dioxide and water and combine
them Into moleoules of gluoose.
Within the glucose moleoule produced by the green plant
Is the energy whloh has been converted from light energy
Into ohemloal energy.
Pats and proteins also contain stored energy.
To use this stored energy(In organic foods) living things
break the bonds that hold the atoms of the moleoule to*
ether and the energy Is released.
hus the energy that Is used by lining things to carry on
the process of life Is the ohemlcal energy stored in
moleoules of carbohydrates, fats and proteins.

f

PRINCIPLE III
Solubility and diffusibility are prerequisites for the
absorption of foods.
1.

2.
3.
4.

Food Is a&ored in the form of large, complex, lnsoluffble
moleoules In both plants and animals and oannot be used
until the moleoules are made simpler and solujfble in
water.
Neither plants nor animals oan transport food material
through the body except In a solu^ble form.
Food oannot be used for energy nor for building proto­
plasm unless It Is In a simple molecular form.
Splitting oomplex moleoules Into simple ones, which makes
them solurfble in water. Is oalled digestion.

PRINCIPLE IV
8
Digestion results In organic food’being changed Into
their soluble and diffusible components.
1.
S.
31
4.

Splitting complex moleoules Into simple ones, which makes
them soluble In water Is oalled digestion.
Digestion Is essentially the same In both plants and ani­
mals.
The process of digestion Is facilitated by the aotlon of
enzymes.
Enzymes are organic catalyst produced by living cells
whloh speed up or slow down ohemlcal reactions without
themselves being used up.

321
5.
6.
7.

8.

9.
10.
11.
12.
13.
14.
15.
16.
17.
13.

19.

20.

21.
22.
23.

In the process of digestion enzymes speed uu the chemioal
reactions,
In the process of digestion enzymes enable the chemical
reaotione to take place at relatively low temperatures,
In digestion water is added ohemlcally.
The chemioal equation for the digestion of staroh la:
(C«HiQ0 5 )n -4- nHoO
— -> nCgF-hoOfi
starch
water
simple sugar
There Is no digestive system in plants,
In plants digestion ocours through enzyme action where-**
ever food is stored.
Digestion in plants may occur in the roots, stems, leaves
or seeds,
After digestion the food Is soluble and can be transported,
usually through the phloem^ to the part of the plant that
needs the energy ar building material.
The growing tips of roots or stems are the usual destina­
tion of such soluble energy-containing foods.
The process of digestion in animals is fundamentally the
same in all forms.
Before digestion oan take place in an animal, it must eat
either plant material o r another animal that has already
fed on plants.
The simplest illustration of the fundamentals of food in­
take and digestion is found in a single celled animal, the
ameba.
The ameba is mlorosclplo in size, lives In water, is
composed of one cell only, and moves by a flowing of the
protoplasm.
When the ameba moves, parts of the cell project forward
as blunt, finger-like prooesses oalled pseudopodia.
The
rest of the protoplasm flows into these processes.
Other
pseudopodia are them projected and again the rest of the
oell flows into them.
When a food particle is met in the wanderings of the
ameba, two or more protoplasmic processes move toward and
around the food until it is completely surrounded.
The
processes also olose over the top and bottom of the food
until it is completely surrounded.
The surrounding of the food particle by the protoplasm
of the ameba forms a space inside the cell which contains
water and the food particle.
This space is known as the
food v a o u o l e •
The food vaouole of the ameba acts as a digestive struc­
ture .
The aiseba protoplasm surrounding the food vacuole secretes
digestive enzymes into t h e vaouole which digest the food
and thus make it soluble.
In the ameba, digested food in the vaouole Is then absorbed
through the vacuolar membrane into the protoplasm, where
it is utilized for energy production or to build m&ro proto­
plasm.

322
24o

The essential features of the processes speoclnted w 1th
food getting In the ameba are (1) foo3 intake (.?•) scoretion
of digestive enzymes by the protoplasm through the membrane
surrounding the vaouole, (3) breakdown of complex food
moleoules by the enzymes into simpler soluble molecules,
(4) absorption of the soluble molecules through the vacuolar
membrane into the protoplasm of the cell*

PRINCIPLE V

Water is a basio medium for life processes*
1.
2.
3*
4.
5.
6.
?.

The protoplasm tf whloh oella are made is from 60 to 90
percent water.
.
Food le stored in the porm of large, complex, Insoluble
moleoules in b o t h plants and animals, and oannot be used
until the moleoules are made simpler and soluble in water.
A n forms (of life) require a certain a m o u n t of water, but
some require less than others.
Chemicals dissolved in w a ter also have an effect on the
kinds of organisms living in any area.
Water comprises over 60^ of the humsn body by weight.
Water is part of the protoplasm and of all body fluids.
Life as we know it would be impossible without water.

\

323
ARi-A b - UTILIZATION OP MATTER AND ENERGY
UNIT s3 - Organ frystems
It is the purpose of this Investigation to discover the re­
lative importance of the facts included in the Lecture Sylla­
bus for Biological Science.
Eaoh fact is to be evaluated in
terms of the contribution which you believe it makes toward
the understanding of a fundamental principle of biology.
Please Interpret the word "understanding” within the limits
you believe to be Imposed by the objectives of general ed­
ucation and the specific objectives of the area in whloh the
principle occurs.
The principles were taken from the
Study Guide for Biological Science.
You will find the prin­
ciples from eaoh area in the study guide followed by facts
taken from corresponding areas of the syllabus.
Will you
rate each fact according to the following key ?
Hark spaoe 1 if you believe that knowledge of the fact
essential to an understanding of the
pr i n c i p l e .
Hark space 2 if you believe that knowledge of the fact
is quite Important to an understanding of
the principle.
Hark spaoe 3 if you believe that knowledge of the f a c t
is of average Importance to an understand­
ing of the principle*
Hark spaoe 4 if you believe that knowledge of the fact
unimportant to an understand­
ing of the principle.
Hark spaoe 5 if you believe that knowledge of the faot
is unrelated to an understanding of the
principle.
THE SPECIFIC OBJECTIVES OF AREA 6, UNIT 2
1.
To understand the structural characteristics of the
digestive, respiratory and excretory systems whloh
function directly in the intake-outgo activities of
living things.
2.
To understand the significance of these organ systems
to the organism as a whole.
PRINCIPLE X
The exohange of matter between organisms and the environ­
ment la accomplished in the simpler organisms by the phy­
sical prooess of diffusion almost exclusively.
In the
complex multloellular animals, supplementary specialisa­
tions of tissues and organs evolved to effect the intakeoutgo activities.
(continued)

Men le a complex animal made of bill lone of o:;Vio,
some of w h l o h are specialised and cor.blned to f orrs a
digestive system.
The digestive s y s t e m (in man) is a tube extending from
mouth to anus through which the food must pace to be
digested.
Associated w ith the digestive tube(in man) arc several
glands, ft’hioh secrete enzymes and other essential materials
necessary for digestion.
Practically all animals must take in free oxygon and must
et rid of oarbon dioxide.
he immediate souroe of oxygen and the place of disposal
for oarbon dioxide is air for land animals and water for
aquatic animals.
The fundamental method of obtaining oxygen and removing
oarbon dioxide is the same for both land and water ani­
mals, though the details of the mechanism ray differ.
The fundamental method of obtaining oxygen and removing
carbon dioxide in both land and aquatic m i m a l s is diffus­
ion through a moist cell membrane.
The cell membrane must be moist or diffusion through It
cannot occur.
The simplest example of the mechanism(of diffusion) is a
single-celled organism, such as the ameba.
The cell membrane of the ameba is covered with water in
whloh the ameba normally lives, and this water contains
oxygen dissolved in it.
Oxygen is also present within the cell, where it is used
in cellular respiration.
Cellular respiration in the ameba removec the free oxygen
from the cell with the result that the concentration of
oxygen within the oell is below that of oxygen in the
water outside.
Therefore, the oxygen diffuses from the
water through the moist oell membrane into the protoplasm
of the oell.
Cellular respiration in the ameba also produces carbon
dioxide, w h i c h accumulates within the cell in quantities
greater than those present in the water outside the cell
membrane.
Therefore, oarbon dioxide diffuses out of the
oell through the moist oell membrane into the surrounding
water.

f

325
pittHCUPLE II
The specializations in the digestive proceno whloh evolved
to meet the organism*a requirements are those .involved In
(1) the mechanical subdivision or foods (£) the increased
secretion of digestive fluids (2) the stirring of the di­
gestive traot contenta (4) the absorption of the ond pro­
ducts of digestion and (6) the reabsorption of u*ter from
the feoal wastes,
1,
2.
2.
4.
5.
6.
7.
8.
9.
10.
11.
12.
12.
14.
15.
16.
17.
18.
19.

The (human) digestive system Is a tube extending from mouth
to anus through whloh the food must pass to bo digested,
Associated with the tube are oeveral glands, whloh secrete
eneymes a n d other essential materials neceoesry for digest­
ion.
The(digestive) tube Is divided into the following parts:
Mouth, throat, esophagus, stomach, small Intestine, large
Intestine, reotum a n d anus.
The major glands that seoreto Into the tube aro cnlivary
glands, gastric glands, liver, pancreas, and intestinal
glands.
The lips form the anterior(forward) boundry of the mouth.
Che palate forms the roof and the ohocka form the side
walls.
The floor Is oooupled by the tongue.
Posteriorly(to the rear) the mouth opcno Into tho pharynx
or throat.
Food Is taken Into the mouth, where It Is broken up by
the chewing action of teeth, tongue, and cheeks.
Food in the mouth Is partly digested by the action of ah
enzyme seoreted by the salivary glands.
Chewing Increases the area exposed to the action of o n - .
zymes and speeds up digestion.
The salivary glands also secrete mucin, which mixes with
the food to make the particles stick together In small
balls and to slide more easily down the throat.
The tongue is a muscular organ that fills the floor of
the mouth.
The tongue aids in ohewing by pushing the food between
the teeth.
The oheeks function In the same manner on
the other side of the teeth.
The upper surface of the tongue Is rough and oontalns
numerous papillae, at the base of which aro taste buds.
There are four taste: sweet, sour, salt and bitter.
There are three pairs of salivary glands.
One pair(of salivary glands) lies bolow and in front of
the ears.
A duct from eaoh(of the salivary glands lyln^ bolow and
In front of the ears) opens Into the mouth opposlvo the
second upper mobar tooth.
The seoond pair(of salivary glands) lies in tho poster­
ior part of the floor of the mouth.
A duot from eaoh gland (lyftng in the posterior part of
the floor of the mouth) opens into the mouth beneath the
free end of the tongue.

20.
21.

The third pair (of eallv&ry elands) 1 lea honorth t:r> tongue.
The salivary glands benoath the ton no ':v:.vn r-. Kiirb^r of
ducts that open along the aldo of tho ton no.
2 2 . The pharynx lies Just behind the no nth.
255. The pharynx le a oorcmon passage vir.j for fo o "> r r ir*
24. The tonalle and adenoids are erlovUon in th- , - t ];; of the
pharynx.
25.
The esophagus le a tube that connect o thr> u r r y
w ;tu
the stomach.
26. The esophagus is lined with an epitholiun.
27. The esophagus contains two layers of rusolo ti roc in its
walls.
28.
Swallowing moves the food from the mouth Into the enoeliagus a nd t hem into the stomaoh.
29. When rrwallowing ooours the food Is moved to tho beck of
the tongue*
The throat muscles contract end guch it into
the esophagus, w h l o h in turn pushes it into the r.tomaoh.
50. The movement of the food through tho esophagus io caused
by the notion of the musole layors In the well of the
esophagus.
51. The notion of the musole layers of the ur-H of tho ocophagus Is oalled peristalsis and is the anno cort of ac­
tion that ooours w hen one squeezes toothpaste out of a
tube.
52. (During peristalsis) the muscles In front of tho roving
ball of rdod relax, while those behind It contract.
55. Both relaxation and oontraotion start at the uopor end
of the esophagus and oontlnue toward the stomach.
The
food is pushed along by the squeezing notion of tho con­
tracted wall of the esophagus.
54. The stomaoh is a n enlarged portion of tho directive tube.
55. The stomaoh acts In part as a sac or reservoir for the
temporary storage of food.
56. The Inside of the stomaoh is liner! with an epithelium and
thousands of glands.
57. The glands of the stomaoh arc of two kinds, tho::e that
secrete digestive ensymes and thoao that eocrsto hydroohlorlo aoid.
38. The wall of the stomaoh contains three layers of srooth
musole tissue.
39. The musole tissue in the wall of the stomaoh squeezes
the stomaoh into a variety of shapes.
40. The squeezing aotlon(of the stomach) churns the food and
breaks it up even more than oocured In tho routh.
41. The squeezing aotion of the stomach nloo foroon the food
into the small intestine.
42. The enzymes seoreted by the glands In the stoorch wall
aot on proteins only*
43. The enzyems produced by the glands in tho wall of the
stomaoh aot only in a n acid medium, honso tho riooccsity
of hydroohlorio aoid In the stomach.
44. Praotloally no food Is absorbed in the otorach.

327
45.

46.
47.
48.
49.
50.
51.
52.
55.
54.
55.
56.
57.
58.
59.
60.
61.
62.
65.
64.
65.

66.
67.

After the food has remained in the storiach for throo or
four hours and has been ohurned and actod upon by enzymes
it la forced Into the email Intestine by a periatr-ltio
wave of the stomaoh wall.
The small Intestine is a oontinuatlon of the digestive
tube.
The small intestine is smaller, though longer, t h m the
stomaoh.
The pylorus, a ring-like band of muoolo, separates the
stomaoh and the small intestine.
The pylorus oont?ole tho passago of food from tho rtomaoh
to the small intestine*
The small intestine is lined, like the otomach, with an
epithelium.
Digestive glands lie in the wall(of the small lntostlno)
beneath the epithelium and seorete into the cavity of the
tube.
The Inside walls(of the small intestine) aro folded and
on these folds finger-like villi project into the in­
testinal oavity.
The folds a n d villi serve to inorease tho surfcoo area
of the (intestinal) epithelium, and thus to increase the
digestive and absorptive oapaoity of the intestine.
The Intestinal walls oontain two layers of smooth nusole.
The Intestinal walls oontain many blood vooselo and nerves.
Connective tissue binds the various structures of tho
small intestine together.
The food and digestive Juloes are thoroughly mixed and
ohurned in the small intestine by peristalsis and the
pumping n o t i o n of the villi.
After a period of churning(in the small intestine) the
food is p ushed along toward the largo intestine.
The liver is a large gland that lies in tho anterior
portion of the abdominal oavity.
One of the liver's many functions is to seorete bile into
the small intestine by way of the bile duot.
The bile mixes w ith the food as it enters tho small intes­
tine from the stomaoh.
Bile emulsifies the fats, breaking thorn up into email
droplets.
The emulslfloatlon process inoreasea the eurfnoo area of
the fat globules and thus aids tho fat digesting enzymes
in their work.
The pancreas lies between the anterior portion of the
small intestine a n d the stomaoh.
The pancreas is oonneoted to the small intortinc by a
duot.
The panoreas secretes three kinds of digestive enzymes
into the small intestine.
They are protein-digesting,
fat-digesting, and oarbohydrate-digesting enzymoe.
Q-lands in the walls of the intestine also secret© pro­
tein and oarbohydrate-digesting ensymes.

328
68.
39.
70.
71.
72.
73.
74.
75.

76.
77.
78.
79.
80.

81.
82.
83.
84.
85.
86.
87.
88.
89.
90.

Digestion of protein changes thsrc to nrrlno acid s.,
Digestion of carbohydrate produces glucose and other
simple sugars,
Digestion of fats results in glycorol and fntty aoids.
The amino acids and simple sugars n.re .absorbed through
the epithelium of the small intestine, into or*'!! blood
▼easels, the capillaries.
Glycerol and fatty aoids go not into tho capillnrioo, but
into the branches of the lymphatic oyoteri locr.tsd in the
▼illi.
The lymphatic system io part of the c i r c u l a t o r y oystem.
The amount of absorption possible (from the email intest­
ine1
.) is dependent on the surface area of the epithelium.
Because the amount of absorption fro.n the email intestine
is dependent on the surface area of the epithelium, the
folded inner lining of the lntestino rnl the flngcr~llke
▼illl are significant.
They increase tho surface area.
After digestion and absorption have taken place, the un­
digested residue plus some unabsorbod food and water pass
into the large intestine.
The struoture of the large intestine is basically the same
as the small intestine.
The large intestine has an epithelium lining the vail and
two layers of smooth muscle tissue that rako up the bulk
of the w all of the tube.
There are no villi in the large Intestine.
The Junotlon of the small and large intestines is not
a direct end to end union, for the small intoatino connects
with the large intestine a short way up from the anterior
end of the large intestine.
The end of the large Intestine that extends beyond the
connection(with the small intestine) has a email fingerlike appendage oalled the vermiform appendix.
Mo digestive enzymes are produced by the lar^o Intestine.
Some digestion and absorption occurs in the Xer^c into*- time.
A certain amount of undigested food plus the enzymos pass
into the large intestine.
The o m y c o continue to act and
the digested foods afe absorbed through its walls.
However, a more important function of the largo Intestine
(than the absorption of digested food) is the absorption
of water.
Absorption removes most of the water frora the large intes­
tine.
The food residues become feoal matter (feces).
The large intestine contains a large nembcr of bacteria
that aot upon and break down farther whatever is loft
over after digestion.
The residue
Tin the large intestine) varies with the diet
but usually oonsletsofif cellulose from plant foods, tough
connective tissue from meat, and some fats.
The odor o f feces is due to the products of bacterial
notion.

91.
92.

93.
94.

Pariotnlols moves the fcoal matter .Into the lo >ar end
of the Intestine and into the rcctun at tho ^oetcrioi*
end of the digestive tube.
Thia (movement of feoos into t h e root tun) e ; c r t ” a proaaure on the walla of the root urn whloh csuoco a poriataltio wave to paea over the entire lnr^o intestine to
the anue.
Straining adds to the pressure on the focoo by contraction
of the diaphragm and the abdominal m u 3oles.
(Peristalsis and straining provide the ctlmuluo), the anal
sphincter relaxes and the feoal matter then panses through
the a n u s .

PRINCIPLE I I I
Respiratory organ systems evolved to offset adequate
gaseous exchanges between the organism and the environ­
ment.
All respiratory organs are characterized by hav­
ing sufficiently large areas of thin, moist membranes
richly supplied with blood vessels to meet tho oxygon
Intake a n d oarbon dioxide outgo demands of the organism.
The air-breathing organisms possess a system of tubos
whloh permit a more ready diffusion of gases to and from
the respiratory surfaces.
1.
2.
0.

4.
6.
6.
7.
8.

Practically all animals must take in free oxygen and
must get rid of oarbon dioxide.
The Immediate souroe of oxygen and the plaoo of dispos­
al of oarbon dioxide is air for land animals and water
for aquatlo animals.
The fundamental method of obtaining oxygon and re moving
oarbon dioxide is the same for both typos(land end aqua­
tic animals) though the details of tho meohanism nay
differ.
The fundamental method of obtaining oxygen and rcroving
varbon'dioxide is diffusion through a moist oell mem­
brane.
The oell membrade must be moist or diffusion through it
oannot occur.
The simples*example of the i,w>ohanlsm(of gaseous exchange)
is a single-oelled organism such as the ameba.
The oell membrane of ameba is covered with the water in
whloh the ameba normally lives, and this water contains
oxygen dissolved in it.
Oxygen is also present in the c e l l (body of the amoba)
where it is used in oellular respiration. Oellular res­
piration removes the free oxygen from tho ooll with the
result that the oonoentratlon of oxygen within the oell
is below that of the oxygen in the water outside. There­
fore, the oxygen diffuses from the water through the moist
oell membrane into the protoplasm of the ooll.

330
9.

XO.

XI.

is.
13.

14.
15.

16.
X?.

18.
19.

20 .

21

.

.

22

Cellular respir a t i o n (al g o ) produces c'T',.on C.XovXCn, t;*iioh
accumulates within the oell in quantities groatcr L5oan
thoee present in the water outsiclo tho coll rc!3brr.no.
Therefore, oarbon dioxide diffuses out of the coll t;-.trough
the moist oell membrane into the surrounding water.
Some aquatlo animals suoh as fiCh and lobster.’ hove s p e d *
al struotures oalled gills for obtaining oxygen fro n the
water and for releasing oarbon dioxide.
Gills are composed of many finger-like fXlaoentG through
whloh blood flows in capillaries.
The outer layer of a (gill) filament is composed of a thin,
cellular membrane that lies over and is adjacent to the
oellular wall of the capillary.
The aquatic animal lives in water whloh contains dissolved
oxygen.
This water flows over the surface of the filaments.
The concentration of oxygen in the water is greater than
in the blood flowing through the capillaries, no diffusion
of oxygen takes place from the water through the moist
oellular rurfaoe of the filament and through the equally
moist oellular wall of the oaplllary into the blood.
Carbon dioxide is more oonoentrated in the capillary blood
(of the gill filaments) than in the surrounding water and
therefore diffuses out(into the surrounding water).
Several moist oell membranes are involved In this mechanism
(of gaseous exchange in a gill b e e r lag animal), but the
underlying principle is the same as in the single-celled
organism.
When blood leaves the gills by way of the vessels it car­
ries oxygen to the tissues of the body.
The oells of these (body) tissues use oxygon ?r. cellular
respiration and thereby keep the concentration of oxygen
in the oells reduoed below that of the blood flowing
through the adjaoent capillaries.
Diffusion again occurs
and oxygen moves from the blood through the capillary wall,
then through the oell membrane to the protoplasm of the
oell.
Tissue fluids surrounds both oaplllarieo and oells, so
the oxygen diffuses through this tlssuo fluid toTho cell.
Carbon dioxide is produced bv oellular r e o p i r a t l o n d n
aquatlo gill bearing animals) Just as in tho oase of the
ameba, with the result that the concentration in the oell
is higher than in the blood flowing .through tho capillar­
ies.
Diffusion takes plaoe from the ooll to tho capillary
blood.
The blood Is returned (from all parts of the body) to
the gills, where oarbon dioxide diffuses out into the
surrounding water.
Lungs are saos oontalned within the thorax end their
inner walls are lined with a thin, moist, oellular mem?
brane.
Just beneath the moist oellular lining(of the lungs) are
millions of blood capillaries.

331
23.
24.
25.
26.

27.
28.
29.
30.
31.
32.

55.
54.
36.
56.

37.
38.
39.
40.
41.
42.
43.
44.
45.

43*

The lining of the lunga la kept moist by the tlasue fluid
whloh always surrounds oalla within the body.
The lun£& of land aniaals differ in complexity but all
are basically alike.
The human respiratory system is a type of oomplex respira­
tory mechanism.
The human respiratory system is composed of two major
parts, the first is a series of tubular struetures that
servo to transport air into and out of the lungs.
The
second Is a paired organ for absorption of oxygen and
elimination of oarbon dioxide.
The two parts of this
paired organ comprise the lungs.
Inside of the nose and extending ba c k into the head is
the paired nasal oavity.
The paired nasal cavity is lined w i t h a moist'epithelium.
The nusal oavity opens into the pharynx.
The pharynx (throat) le a common passageway for air and
food.
The larynx opens into the pharynx Just in front of the
esophagus.
The larynx is a oyllndrloal structure with oartllage in
its walls.
In the male some of these o a r t l l a g e s d n the larynx) pro­
trude, forming the adam'e apple.
Within the larynx are the vooal cords, which are connec­
tive tissue bands whloh stretch across the oavity of the
larynx.
The glottis is the opening of the larynx into the pharynx.
The epiglottis is a flap of oartllage that extends up­
ward for a short distance into the pharynx.
During swallowing the epiglottis forms a oover for the
glottis and prevents food or water from entering the larynx,
The trachea is a cylindrical tube that extends from the
larynx into the chest oavity.
The walls of the trachea oontain 9-shaped oartllagenous
rin&c that keep the hraohea permanently open.
Tho trachea is lined w i t h a moist, oillated epithelium.
The mlcrosoopio cilia on the epithelium beat toward the
pharynx and remove inhaled foreign particles.
The trachea branohes within the cheat oavity into right
and left primary bronohl ., whloh are smaller, but other­
wise similar to the traohea.
The primary bronchi branoh into eeoondary bronchi, whloh
branch and rebranch, eventually forming mlcrosoopio
tubule
Thu microscopic air tubules end In small air sacs.
T h e air sacs attached to the mlcrosoopio tubules super­
ficially resemble a bunch of grapes.
The walls of the air s a c s (of the lungs) are thin and con­
tain millions of blood capillaries.

47.

The oaplllarles in the walla of the air spacer! of the
lunga are supported by connective tissue,
sore of t’hioh
is elastic.
48.
Whether the air <$aos(of the lunga) are lined with an epi­
thelium la a n open question.
49.
The exchange of oxygen and carbon dioxide in the lunga
takes plaoe in the lining of the air sace.
60. The thoraolo oavitji contains the lunga.
81. The thoraolo oavlty is divided into right and li)ft
pleural oavltles by a thlok median partition.
62.
Each pleural cavity oontalna a lung.
63.
The muscular diaphragm forms the floor of the thoracic
oavlty and separatee it from the abdominal oavlty.
64.
Breathing eonslst of inhaling and exhaling, or the move­
ment of a i r into and out of the lunge.
66.
Inhalation results when the air preeeure within the lungs
falls below atmospheric pressure, tjlth the ooneoquonoe
that atmospheric pressure pushes air into the lungs.
66.
The pressure within the lungs la lowered by enlarging the
thoraolo oavlty.
67.
Enlarging the thoraolo cavity is accomplished by moving
the walls of the thoraolo oaglty out and by lowering the
floor.
68. The ribs lie within the walls of the thoracic oavlty. 0ontraotlon of oei*taln ohest mu cole a which are attached to
the ribs causes the ribs to swing out and produoe a later­
al enlargement of the oavlty.
69.
The floor of the thoraolo oavlty is made up of the mueoular diaphragm.
It Is dome shaped, w i t h the dome extending
upward into the oavlty.
Contraction of the diaphragm flat­
tens the dome a n d enlarges the space within the oavlty.
60.
Exhalation Is accomplished by the oollapse of the lungs.
61. The lungs oontaln elastlo tissue whloh stretches when
they expand during inhalation.
When the ohest musoles
and the diaphragm relax, b oth the walls and the floor of
the ohest oavlty return to their original position.
This
releases the stretohlng pressure on the lunge and they
oollapse m u o h like a leaky balloon.
62. The analogy w ith the balloon is not quite exact beoause
each a i r m a o increases a n d doorcases in slxe during breath­
ing.
The entire lung increases and decreases in size
accordingly.
63.
The lungs are not to be though* of a s empty sacs similar
to one rubb e r balloon, but rather to millions of tiay
balloons held together in a compact mass.
Each of the
tiay balloons has a n air tube oonnecting it to the main
passageway.
64. The Inhaled air eventually reaohes the air sacs, whose
walls are thin and moist and oontaln capillaries.
The
air oontalas a greater concentration of oxygen than does
the blood flowing through the oapllllario, oo the oxygen
difftysee into t h e blood.

333
65*

66.
67.
68.
69.
70.
71.

72.
75.

74.
75.

76.
77.

The concentration of oarbon dioxide In thj r.ir cr-os of
the lungs la lees than that In the blood, oo it(UiD carbon
dioxide) diffusee in the opposite direction, that io, from
the blood of the capillaries to the air spaces in the air
eaos.
Oxygen is transported by the hemoglobin contained in the
red blood oorpusoles.
Hemoglobin is a red pigment that unites easily with oxy­
gen, forming the compound oxyhemoglobin.
The oxygen also beoomes separated from the hemoglobin
easily under oertaln conditions.
In the lung oaplllarles the oxygen comb1n o e with hemo­
globin, forming oxyhemoglobin and as such travels baok
to the heart to be distributed throughout the body.
Finally it(the
oxyhemoglobin) reaches the tieeues of the
body where there is little or no oxygen.
The oxygen then
separates from the hemoglobin and diffuaoa into the cells.
(After the oxygen separates from the hemoglobin) the hemo­
globin in the red oells oontlnuee on into the veino through
the heart a n d b a o k to the lungs; where it picks up another
load of oxygen and oarrles it to the tissues again.
Oarbcm dioxide
is transported In the blood by both red
oorpusoles a n d plasma.
Carbon dioxide is produced i n the oells of the body, where
it is picked up by the blood; then it is carried to the
lung oapllln?les.
From the lung capillaries it diffuses
into the air spaces of the air sacs and is breathed out.
The xylem and phloem which:.make up the vascular bundles
are the main conducting tissues in plants.
There are no special structures t o transport gases in
plants though there are openings such as the ctomates in
leaves and lentloels in bark which permit the a i r to enter
and leave.
In plants, the transport of oxygen to respiring oells and
the transport of carbon dioxide away from thorn is by
diffusion.
The oarbon dioxide that the plant oells use in photo­
synthesis also is transported by diffusion.

PRINCIPLE IV
Excretory organ systems evolved to maintain normality
in the chemical composition of fluldo comprising the
internal environment of the orgsniem.
In the multicellular animals this is accomplished by a 3ystem of
tubes and channels of varying degrees of oomplexity
whloh permit the outgo of metabollo wastes filtered
from the blood or other body fluids to the external
environment.
1.
2.

Metabolic processes in the body result in the production
of useless or harmful materials that ruct be eliminated.
Carbon dioxide produced in the oello is eliminated by the
lungs.

33k
3.

Food residue is eliminated as feces from t;ha digestive
tract.
4.
The nltrogen-oontain&dg wastes are excreted by the kid­
neys a n d leave the b o d y as urine.
6.
The kidneys also regulate the composition of the blood,
particularly w i t h respect to water and glucose.
6.
The(human) urinary system consist of two kidneys, two
duets known as ureters, which drain urine from the kid­
neys, the bladder, w h i o h is a reservoir for urine, and
a single duet, the urethra, w h i o h carries urino from the
bladder to the outside of the body.
?.
The kidneys are b ean-shaped structures about four and onehalf inohes in len g t h that lie a l o n g the dorsal wall of
the abdominal oavlty.
6.
Eac h kidney is composed of many small renal units whioh
oolleotlvely secrets the urine.
9.
Each renal unit consists of a small ball of oaplllarles,
the glomerulus, through whi o h blood containing nitrogen­
ous waste flows.
10.
The glomerulus is surrounded b y a microscopic cup-ehaped
struoture, the glomerular oapaule.
11.. A small tube, the r e nal tube is a t t a c h e d to the glomeru­
lar capsule.
12.
E a c h renal tubule oonnedts with other ronel tubules which
come f r o m o t her capsules t o form a larger duot that empties
into a chamber in the central part of the kidney.
13.
The ureter is attached to the central ohamber of the kidney.
14.
The blood carries waste materials from the boby colls to
the kidneys.
15.
Within the kidneys the blood(containing nitrogenous wastes)
flows through the glomeruli within the many glomerular
capsules.
16.
The pressure of the blood oauses the fluid of the blood
plus the wastes and other substances in solution(mainly
gluoose) t o filter through the oaplllary walls into the
oavlty of the oapsule.
1?.
This liquid (glomerular fllterate), w h i c h is, really blood
minus the cells and the larger plasma proteins, passes
into the tubule that drains the capsule.
18.
As the liq u i d (glomerular fllterate) passes through the
tubule the cells lining its walls extract most of the
water and dissolved aubstanoes, leaving the wastes and
some water.
This is urlns.
19.
It (urine) leaves the kidneys by way of the ureter whioh
carries it t o the bladder.
20.
Hie urethra carries it (urine) from the bladder to the out­
side (of the body).
21.
Plants have no speolal system to oarx»y on the function
of exoretlon.

335
22.
23,
24,
25.

The excess oxygen produced during photosynthesis diffuses
out through the stornates of the leaves.
Carbon d&oride produced by oellular respiration way be
eliminate
also by diffusion It it 1c not uoed in photo­
synthesis.
Other wastes are stored In various parts of the plant.
These wastes(of the plant) Include oils, gums, resine,
organlo acids, tannins, alkaloids, pigments and certain
useless minerals.

336
AREA 5 - UTILIZATION O F M A T T E R A N D ENERGY
UNIT 0 - Celle a n d the Internal Environment
It la the purpose of thle Investigation to dlsoover the re ­
lative importance of the faote included in the Lecture Sylla­
bus for Biological Science.
E a c h faot is to be evaluated in
terms of the oontrl b u t l o n w h i o h ;~ou believe it makes toward
the understanding of a fundamental principle of biology.
Please Interpret the w o r d ■u n d e r s t a n d i n g ■ within the limits
y ou believe to be imposed b y the objectives of general ed­
ucation a n d the specific objectives of the area in w h i oh
the principle oocurs.
The principles w e r e taken from the
Study Guide f o r Biological Science.
Y o u will find the prin­
ciples from e a c h a r e a in the study guide followed by faots
taken from oorreepondlngnareas of the syllabus.
Will y ou
rate eaoh faot a c c o r d i n g to the following key T
Mark apaoG 1 if y o u believe that knowledge of the faot
is essential to a n understanding of the
principle.
Ma r k apaoe 2 if y o u b e l i e v e that knowledge of the faot
is oulte important to a n understanding of
the p r i nciple
M a r k space 3 if y o u believe that knowledge of the faot
la of ave r a g e importance to an understand­
ing of the principle.
Mar k apace 4 if y o u b llove: that knowledge of the faot
la T|i||\*f1iT unimportant to a n understandlag of the p r i n c i p l e •
M a r k space 5 if y o u believe that knowledge of the faot
it unreimted to a n understanding of the
principle.
THE SPECIFIC OBJECT I V E S O F A R E A 5, U NIT 3
1.
To g a i n a n understanding of the structure a n d funct­
ion of blood.
S.
To k n o w the substenoee transported by blood a n d the
functions of these substances.
3.
To understand the relationship between the evolution­
ary development of organisms toward greater complex­
ity a n d
the development of transport systems.
PRINCIPLE Z
Transport is a means of bringing food, gases, hormones
a n d ant i b o d i e s to plaoe of utilisation.
It is also a
means of removing wastes.
1.

The food that organisms use a s a source of energy and for
building body structures must be transported from the
p^aoe of di g e s t i o n a n d absorption to the various parts
of the b o d y where It is used.

2.
3.
4.
5.
6.
7.
8.
0.

10.
11.
12.
13.
Id.
16.
16.
17.
18.
19.

20.
21.
22.
23.
24.
25.

The oxygen thatt is u sed to release the ohomloal energy
oontalned In rood must be transported from lte place of
entry to the m any plaoes of use*
Many other substances essential to normal functioning of
the body m ust be oarrled f r o m place to place*
Finally, the wastes p r o d u c t s of living processes must be
removed*
The chief method o f transport used by all organisms, both
plant and animal, la diffusion.
In some small
organisms this(diffusion) alone Is sufficient,
but In larger forms d i f f u s i o n Is not fast enough and addition
al means of transport are necessary.
These (additional means of transport) include the blood and
blood vessels of animals, the air tubes of land animals,
and the oo n d u o t l n g tissues o f plants.
Blood Is m ade of a liquid portion, the plasma, a n d a cellu­
lar part, the oorpusoles.
The plasma la mainly w a t e r containing several substances
dissolved In It, a m o n g them blood proteins, mineral salts,
food, wastes products, hormdnes, antibodies, a n d gases
such as o a r b o n dioxide and oxygen.
The blood pro t e i n s are a p art of the blood and are not to
be considered a s food b e i n g transported.
One of the blddd proteins Is firblnogen, w h ioh Is Important
In blood clotting.
Plasma w i t h fibrinogen removed la called serum.
l y mph is a part of the b l o o d that h a s left the vessels and
filtered out Into t h e tlssuee.
The volume of b l ood In a n adult averages five or six quarts,
depending o n the else of the individual.
The blood eorpueclee Include the r e d oorpusoles, the white
oorpusoles, a n d the platelets.
The red oorpusoles are small olroular dlsos shaped some­
what like a doughnut.
There is no nucleus in the red oorpusoles of mammals.
A r e d pigment k n own as hemoglobin, is oontalned within the
oorpueoles a n d la the means of transporting oxygen.
When free oxyg e n is abundant it readily forms w i t h hemo­
globin a loose ohemloal union whi o h is as readily broken
when the oorpusoles enter areas in tho body where there
Is a soarolty of oxggen.
The re d oorpusoles originate In the red bone marrow.
During development they(red corpuscles) possess a nuoleus
w h i o h Is lost before the oells r e aoh the olroulatlng blood
stream.
R ed oorpusoles are fairly oonstant in number.
In oertaln dlseaees the number (of r e d oorpusoles) falls
below normal.
Suoh a condition is known a s anemia.
The white oorpusolee are larger than the red, have a nuoleus
a n d oontaln n o hemoglobin, and some oan move under their
own power.
White oorpueoles originate in red bone marrow and lymph
nodes.

m

338
26.
2?.
28.
29.
30.
31.
32*
33.
34*
33.
36.

37.
38.
39.

40.
41.
42.
43.
44*
45.

There are f e w e r white oells in the blood then red oells
and they w a r y more In number.
The warlability(of white cells) in number is linked up
with their primary function, w h i c h Is to aid the body
In combating Infection.
When baoterla enter the body, the white oorpueoles d u s t e r
around a n d Ingest them.
The white oorpuscles more from p l ace to plaoe In the body
w i t h i n .the b l ood stream, but also they can leave the blood
vessels a n d move through the tissues.
White oorpusoles mows by means of pseudopodia or protoplas­
mic processes In the same manner as a n ameba.
The white oorpusoles a l s o engulf a n d digest bacteria as
a n ameba d oes food*
When a n Infection Is present (in the Qody) the number of
white oorpusoles Increases*
The Increase In white blood oorpusoles is used by the
physician to determine whe t h e r mi.suspected Infection Is
present, suoh a s In th& diagnosis of appendicitis.
The platelets are small, colorless, round or spindleshaped bodies about one third the size of red oorpusoles*
The plat e l e t s hare a n Important function In b l ood clotting*
A solid, orusty plug forms over a wourtd shortly after the
blood leaves the vessels a n d flows over the skin.
This
p l u g ”, stops the leakage of blood f rom the vessels an d Is
£nown as a d o t *
The ohomloal changes that result In the formation of the
clot from the liquid b l o o d start w h e n the platelete d i s ­
integrate •
The platelets are very fragile and burst whenever they
come In oontaot w i t h a r o u g h surfaee.
When the platelets disintegrate they release a substance
w h i o h rea c t s w i t h the blood plasma to produoe thrombin,
a n enzyms-llke substanoe, w h i c h in t urn reacts w i t h
fibrinogen, a normal pro t e i n constituent o f the blood.
The fibrinogen Is changed Into Insoluble fibrin*
The red
oells are oaught In the meehwork t9 f orm a b l ood d o t *
The steps In the olottlng of blood are a s follows:
Thrombin +
Fibrinogen
->>
Fibrin
F i b r i n 4 Oells
Clot
A thrombus Is a blood d o t in a b l o o d Vessel.
A n embolus Is a thrombus that is moving freely In the
blood stream*
Coronary thrombosis Is the oause of many heart attacks,
a thrombus or embolus p lugging one of the blood vessels
of the hea r t and stopping the flow of blood.
Stopping the flow of b l ood in one of the blood vecsels
of the heart prevents oxygen and food from getting to
the heart musole tissue.
A stroke m a y be oaused by a n emboluo, or a thrombus, becosting lodged In one of the blood vessels of the brain*

339
46.
47.
48.
49.

60.
61.

62.
68.

54.
56.

56.
57.

58.
69.
60.
61.

Hemophilia is a disease in whioh a p e r s o n 1a blood does
not olot quickly enough to prevent severe and sometimes
fatal bleeding.
One tppe of hemophilia is hereditary a n d is thought to
be due to t h e laok of fragility of the platelets.
In the hereditary type of hemophilia the platelets do
not disintegrate rapidly enough to initiate the chemical
reaotlons normally Involved in blood d o t t i n g .
The blood of h u m a n beings differs, so it cannot be.
mixed indiscriminately in transfusion.
If different types
are mixed, the red oorpusoles may clump or agglutinate
and oause death.
They may also disintegrate with equally
fatal results.
The differences in human blood oause blood to be categori­
sed into groups.
These are known a s the 0 group, the A
group, the B group a n d the A B group.
Another type of blood group wioh is Important in trans­
fusion is known a s the Rh.
The R h group &s not related
in notion to the 0, A, B and A B groups and must be con­
sidered separately.
Understanding of the importance of the blood groups in
transfusion depends on a n understanding of the antigenantibody reaction.
Thls(antlbody-antlgen rsaotlon) Is based on the faot that
when a foreign protein Is injected into an animal, the
lnjeoted animal's body reaots b y manufacturing a oherrloal
substance to oounteraot the effect of the injected protein.
The substance Injected Is oalled an antigen a nd the sub­
stance produced because of the presenoe of the antigen is
oalled a n antibody.
The antlbody-antlgen reaction is the basis for immuni­
sation against suoh diseases as smallpox, diphtheria,
whooping oaugh and typhoid fever.
To Illustrate (the antlbody-antlgen reaction), diphtheria
Is oaused by a germ that produoes a poison known as toxin.
If the t o x i n In lnjeoted Into a human being or if It enters
naturally because of a n Infection, It acts as a n antigen
and stimulates the body to produce a n antibody known as
antitoxin.
The antitoxin neutralises the toxin.
The fatalities that result from mixing different types
of blood la transfusions are due t o a n antlbody-antlgen
reaotlon.
The anllgen-antlbody process differs in the blood groups
from the reaotlon described in the diphtheria example in
that the antigens do not stimulate the production of the
antibodies.
Both antigens a n d antibodies are present in normal blood,
having been produced during embryonlo development.
Certain hereditary determiners, the genes, cause develop­
ment of b o t h antigens and antibodies To onoerned in ordi­
nary blood groups;•
The ant i g e n s are present in the red blood oorpusoles.
There are two kinds of antigens, A and B.

3U0

62.

65

.

64.

66.
66

.

67.

68

.

69.
70.
71.
72.

78.

74.

76.
76.
77.
78.
79.

A person may have A ant & g e n only, or he may have the
B antigen only, or he may hare both A and B.
It is
also possible for a person to have no antigens In the
red oorpusoles.
If he has antigen A he belongs to blood group A.
If
he has antigen B, he belongs to blood &roup B.
If he
has neither A or B antigen, he belongs to group 0.
The antibodies are of two kinds and aro known as •a*
an d *b*.
When red oells oontalnlng the A antigen are mixed with
serum oontalnlng the "a" antibody the blood cells clump.
Likewise clumping ooours w h e n B antigen is mixed with
"b* antibody.
It is obvious (from this) that a normal person of blood
group A h a v i n g antigen A does not have antibody "a " . If
he did the r e d oorpusoles would olunp.
However, he (a person w i t h blood of group A) does have
antibody ”b ” .
A B-group Individual looks ”b ” antibody but has antibody
•a*.
An AB Individual has neither "a” nor ”b" (antibodies).
A person belonging to group 0 has b o t h *a" and flb*
antibodies.
It le impossible to m i x any two kinds of blood without
uniting either A w i t h "a" or B wi t h "b".
Nevertheless,
blood types are mixed in transfusion and one of them,
known as the universal reolplent type, Is able to take
any of the other type s. Another type, the universal
donor, ean be used In transfusion to any of the others.
How le thlej (mixing o f A w i t h ”a ” or B w ith "b")possible?
The answer Is to be found In the difference in Quantity
of blood between the donor and recipient.
The quantity
of the d o n o r 1a blood that Is transfused is muoh less than
that of a reolplent and Is qulokly diluted by the reolp-V’ /
lent's blood In the btod.d bessels.
The antibodies of the
donor are thus diluted to suoh an extent that their effeot
Is negligible.
The donor*s r e d oorpusoles, however, are very qulokly
acted upon b y the antibodies of the recipient be oause
of the relatively large quantity of the reolplent *s anti­
bodies.
In a transfusion It Is necessary to be sure that the don­
or's red oorpusoles d o not oontaln a n antigen that will
reaot w i t h the reolplent*s antibodies.
The universal donor is group 0 beoause its red blood oells
oontaln neither antigen (A nor B).
The universal reolplent Is group A B because Its serum
oontalns neither antibody ("a" nor "b” ).
The R h b l o o d group la oaused by the presence of an antigen
known as the R h faotor in the red oorpusoles.
As l t ( t h e R h faotor) acts Independently of the A, B, AB
a n d 0 groups a person m a y have the R h faotor plus any of
the A or B combinations*

3Ul
80.

81.

82.

83.
84.

85.
86.
87.
88.
89.

90.
91.
92.

93.
94.
95.
98.
97.

Thera le no normal antibody to the R h antigen but It
may oauae antibody production If blood of an R h positive
person (having R h antigen In red oelle) Is transfused
Into a n R h negative person.
If at some future time a second transfusion of R h posi­
tive blood le made(Into a n R h negative individual who
has re&dlved a previous transfusion of R h positive blood),
the R h ant i g e n reaota w ith the antibodies and death may
.result.
Another serious consequence is oausod when an Rh-negatlve
expectant mother marries a n Rh-poeltlve child.
A few of
the red oorpusoles oontalnlng the R h antigen leave the
blood stream of the unborn child, get Into the mother's
blood stream and stimulate the production of antibodies.
The antibodies of the mother diffuse Into the blood
stream of the embryo a n d destroy the red oorpusoles.
R h antibodies usually do not affeot the first child, but
subsequent offspring nay suffer.
Death of the embryo may result(from affects of R h In­
compatibility) or, if dea t h does not oocur, development
may be Impaired and a n anemlo or feebleminded child may
result.
The(human) olroulaftory system oonslst of heart, blood,
blood vessels, a n d l y mph vessels.
The heart pumps the b l o o d through the blood vessels to
all parts of the body a n d back again.
There are
two olroults (to the olroulatory system), the
pulmonary a n d the qystemlo.
The pulmonary olroult carries the blood to the lungs and
baok to the heart.
The systemlo olroult oarrles the blood to all other
parts of the body Including the head, visoeral organs,
arms, legs and body musoles.
The blood following this
olroult also returns to the heart.
The heart Is a musoular pumping organ.
It(the heart) Is a little larger than the person's fist
and lies In the thorax, the tip extending to the left of
the akid—line •
The heart Is constructed of four ehambers oalled the
right and left aurloles a n d right a n d left ventricles.
A musoular > a l l separates the right and left sides of
the heart.
The right aurlole reoeIves blood from the systemlo cir­
cuit a n d sends it Into the right ventricle.
From the right ventricle the blood Is pumped to the
lungs.
The left aurlole reoelvea the blood returning from the
lungs and sends It Into the left ventrlole, whioh pumps
It Into t h e systemlo Olroult.
Valves guard the openings between the aurloles and ven­
trlole s.
.
These valves(between aurloles and ventricles) consists
of flaps of tissue that not like a n ordinary door; that
•Is, they open In one direction only.

3k2
98.

99.
100.
101.
102.
108.
104.
106.
106.

107.
108.
109.
110.
111.
112.

113.
114.
115.
116.
117.
118.

When the blood
flows from the auricles to t h e ventricles,
the valves are puehed open by the flow of blood but when
the ventrlolee oontract, the blood c a n n o t
flow into the
aurloles because t h e ’valvea are forced shut.
The ar.terles that carry blood away from the ventricles
also oontaln valves.
The pulmonary v a lve is In the pulmonary artery and the
aortlo valve In the aorta.
These v a l ves(In the arteries) open when blood flows out
of the ventricles, but close w h e n the blood attempts to
flow b a o k Into the heart.
The walls of the heart are composed of a type of muscle
tissue oalled oardlao musole.
The outstanding feature of this(oardlao) musole Is that
It oontraots a n d relaxes alternately and r h y thmically.
The contraction(of oardlao muacle) eends the b l ood Into
the vessels a n d relaxation permits the heart to fill with
blood again.
The arteries oarry blood away from the heart.
The arteries are thlok - w a l l e d blood vessels- composed of
three layers.
The Innermost layer Is a thin, cellular
layer oalled the endothelium.
The middle layer is thick­
er and Is composed of smooth musole.
The outside layer
Is composed of connective tissue.
In the Jar g s r arteries there Is a large amount of elastic
connective tissue.
The largest arteries are t h o s e leading from the ventricles.
The larger arteries b r a n o h a n d rebranch, gradually getting
smaller a n d emaller until they are quite minute In the
tlesues.
The smallest(arterlee) oonneot dlreotly to the oaplllarles
In the tlesues of the body.
The major systemlo art e r y Is the aorta that carries blood
fro m the l eft ventricle.
The aorta extends forward from the heart and t h e n bends
backward to continue to the posterior part of the body
along the mid-line of the baok Just under the vertebral
column.
Branches from the aorta at the bend carry blood into the
head.
One branoh goes up the right side of the neck and
another up the left side.
The ar teries that go to the arms also leave the aorta in
this r e g i o n (of the backward bend of the aorta).
Several a rteries leave the aorta ftlong the b a o k and oarry
blood to the stomach. Intestine, a n d other organs In the
abdominal o a v l t y •
In the p elvic region the aorta branches Into two arteries
w h i c h extend Into the lege.
The pulmonary artery carries blood from the right ventrlole
to the lungs, where the artery breaks up into minute cap­
illaries.
The vei n s oarry blood b a o k to the heart.

3h3
119.

,

120

121.
122.

123

.

124.
126.

123.
127.
128.
129.

130.
131.
132.
133.
134.
136.
136.
137.
138.

139.

Veins have the same three layers that are present in
arteries, but they(veins) are much thinner called.
There Is little musole or elastic connective t issue in
veins.
Valves that prevent the blood from flowing in a direct­
ion away f rom the heart are found &t Intervals a long the
veins.
Blood f l o w i n g through oaplllarles In the tissues Is colleoted by the smallest veins.
These connect to larger
veins w h i o h in turn oonneet to still larger ones.
The
largest veins flow Into the auricles of the heart.
Blood returns to the heart from the head by way 6t the
Jugular veins.
alood r e t u r n i n g to the heart from fthe head and arms Is
oarrled by veins that meet in the thorax to f o r m the
anterior vena oava wfeioh opens Into the right aurlole.
The blood from the legs a n d baok muscles and abdominal
organs returns t o the h e a r t by way of volns that Join
to form the posterior vena oava, w h i c h lies along the
mid-line of the b aok parallel to the aorta.
The po s terior vena oava empties Into the right aurlole.
The blood that ploks up food from the digestive tract
flows to the liver.
In the liver the blood f rom the digestive tract passes
through a network of oaplllarles before It returns to
the heart.
This(the fact that the blood from the digestive tract
flows thr o u g h capillaries In the liver) enables the
liver t o remove the exoeas glucose and amino acids be­
fore the b l o o d goes to other parts of the body.
The oaplllarles are thin walled vessels that form an
extensive network throughout all body tissues.
The capillary walls are a single cell In thickness.
The capillary tubes are so small that red oorpuscles
must pass through them In single file.
The number of oaplllarles in any given area of tissue
Is very large.
There are 2,000 oaplllarles In each square millimeter
of musole.
It Is beoause of the large number of capillaries that
oxygen a n d food can be qulokly a n d efficiently trans­
ported to oells a n d wastes products can be oarrled away.
Boattered through the tissues along w i t h the blood
oaplllarles are the l y mph capillaries.
The ly mph oaplllarles are oonstructed in the same way
as blood oaplllarles, but they dif f e r in that they are
olosed a t one end.
At their open ends the lymph capillaries interconnect
like the twigs of a tree, forming a branch w h i c h forms
larger l y m p h vessels w h i o h in turn unite to form large
lymph duots.
The lym p h duots empty Into certain large veins near the
heart.

140.

At IntsrtAls Along the lymph vessels are lyffiph nodes o p
lands.
he lymph nodes are little masses of connective tissue
filled w i t h white blood oells.
The fu nction ofi'She lymph g l a n d b is to sepve as a plaoe
for the pr o d u o t l o n OifVhite blood oells.
Lymph glands also filter out and destroy bncterla contain­
ed in the lymph that flows through the vessels.
The ly mph oaplllarles d r a i n some of the tissue fluid from
the spaoes between the odlls.
The lym p h oaplllarles a l s o oarry fat from the small in­
testine.

?

142.
143.
144.
146.

PRINCIPLE II
The fluids o f the transport system constitute the Immed­
iate environment of living oells.
1.
2.
3.
4.
6.
6.
7.

The oaplllarles lie Immersed In tissue fluid that also
surrounds every oell In the body.
Oxygen a n d food materials diffuse from the blood through
the oaplllary walls into the tissue fluid.
From the tissue fluid It(oxygen and food materials) dif­
fuse into the oells.
Carbon dioxide a n d other waste materials diffuse from
the oells through tissue fluid into the blood of the
oaplllarles.
Tissue fluid Is a part of the blood that filters through
capillary walls.
It(tissue fluid) bathes the oells of the body and then
passes Into the lymph vessels or baok Into the capillaries.
The lymph oaplllarles drain some of the tissue fluid from
the spaoes between the oells.

PRINCIPLE III
The evolutionary development o f transport systems In
organisms Is oorrelated w i t h a n lnorease In organism
slse.
1.
2.
3.
4.

The <?hlef method of transport used by all organisms, both
plant a n d animal, la diffusion.
I n some small organisms this(diffusion) olono Is euffl* :■* olent, but In larger forms diffusion Is not fast enough
an d additional means of transport are necessary.
These (additional means of transport) Include the blood
and blood vessels of animals, the a i r tubas of land ani­
mals, a n d the oonduotlng tissues of pbants.
Unicellular animals suoh as ameba live entirely surround­
ed by w a ter that contains In solution the oxygen that the
organism needs.
This oxygen diffuses from the water Into
the protop l a s m (of the ameba).

3U5
do

6.
7.

Since the ameba Is small* the oxygen (the t diffusion into
the ameba's protoplasm) must travel only a short tfiotanoe to reaoh all parts of the individual.
Tor this
short distance the rate of diffusion ic odor-unto to keep
the ameha continuously supplied with oxygen.
Carbon dioxide* a waste product of metabolism, diffuses
out of the oell(ameba) into the surrounding water.
Food diffuses in a similar manner.
If the food is in
solution outside the organism* It diffuses in.
If It Is
not In solution* It is digested in a food vacuole within
the oell and from this vacuole it diffuses to all parts
of the oell.

3U6
AR2A VI- COORDINATT1'AT AND ADJUSTMENT
UNIT 1 - Nervous Coordination
It is ths purpose of this Investigation to discover the relative importance of the facts Included in the Lecture Sylla­
bus for Biological Science.
Each fact is to be evaluated in
terms of the contribution which you bli^ve
it w a k e s toward
the understanding of a fundamental principle of biology.
Please Interpret the word "understanding" within the limits
you believe to be imposed by the objectives of general ed­
ucation and the specific objectives of the area in which
the prlnoiple oocura.
The principles were taken from the
study Guide for Biological Sclenoe.
You will find the prin­
ciples from each area in the study guide followed by facts
taken from corresponding areas of the syllabus.
Will you
rate each faot according to the following key ?
Hark space
if you believe that knowledge of the faot
i® essential to an understanding of the
principle.
Mark space
If you believe that knowledge of the fact
i® Quite Important to an understanding of
the principle.1
‘ Mark space
if you believe that knowledge of the fact
is of average importance to an understand­
ing of the principle.
Mark space
if you believe that knowledge of the faot
i® relatively unimportant to an understand­
ingortheprlnoiple.
Mark space
if you believe that knowledge of the fact
i® unrelated to an understanding of the
principle.
THE SPECIFIC OBJECTIVES OF AREA 6 # UNIT 1
1. To understand that irritability is a fundamental
characteristic of living matter.
2. To know that the structural and functional unit of
the nervous system of most animals is the neuron.
S. To understand how nervous tissue functions to reoeive, conduct, and associate nerve impulses set up
as responses to speolflo environmental stimuli.
4. To understand that animal behavior has its basis in
the quality and degree of organization and associa­
tion of nervous elements.
5. To realize that human intelligence is a consequence
of the quality and degree of organization and associa­
tion of nervous elements.

3U7

PRINCIPLE I
A characteristic property of protoplasra la ite capacity
to respond to stimuli of various kinds.
1.
2.

The ability to receive stimulation and respond to it is
called irritability.
Irritability is inherent in all living things.

PRINCIPLE II
The ability of organisms to adjust to their surroundings
is dependent upon the fundamental property of Irritability
in living things.
1.
2»
3.
4.
6.

Living things adjust to the environment.
Living things are sensitive to their surroundings and re­
spond to them.
The ability to receive stimulation and respond to it is
oalled irritability.
Irritability is Inherent in all living things.
Unicellular animals and plants respond to environmental
stimuli, though in general they have no structures special­
ized for this purpose.

PRINCIPLE III
The nervous system is a mechanism whioh regulates and coordi­
nates the activities of various parts of the animal body,
making it possible for the animal to act as an integrated
unit.
1.
2.

3.
4.
5.

6.

?.

Life is characterized by activity.
(The activity of life) may be the activity of growth, such
as the growth of roots a n d stems or the growth of man from
Infancy to adults or it may be the activity of parts of
an organlsm;or it. may be the aotlvlty of an animal moving
from place to place.
All (life) aotlvlty (of organisms) must be controlled and
coordinated.
All animals inclddkng man have specialized tissues that
aid in adjusting the individual to the environment.
(These specialized) tissues which also coordinate the parts
of the body are the nervous and endocrine tissues, which
in higher animals are evolved into nervous and endoorlne
systems.
The nervous system of man and other vertebrates has three
major p a r t s s (1) the central nervous system, (2) the
peripheral nervous system, and (3) the autonomio nervous
system.
These three systems are interconnected, extend to all parts
of the body, and function something like a telephone system
in a city.

3U8
Q*
9.
10.
11.
12.
13.

14.
lb.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.

Messages received at any point can be quickly relayed to
any other part of the body.
(But) Just as a telephone message must go through "central”
so all nervous messages must go through the central nervous
system before passing on to their intended destination.
The central nervous system is oomposed of the brain and
spinal cord.
The brain lies in the head, entirely surrounded by a bony
oovering, the cranium.
The spinal cord connects with the brain and extends down
the middle of the baok within the vertebral column.,
Nerves leave the brain and spinal cord and connect to mus­
cles and glands in all parts of the body Just as telephone
wires extend from "central” to telephones in all parts of
a city.
The peripheral nervous system comprises the nerves that
extend from the brain and spinal cord to muscles and glands
in the outlying part8 of the body.
The autonomic nervotfs system oonslsts of nerves that con­
nect the brain a nd spinal cord to the internal organs of
the body such as the heart, the stomach, and the intestines.
The specialized oells that make up the nervous tissue and
the nervous system are the neurons.
Each neuron has a cell body containing oytoplasm and a
nuoleus.
From this oell body two kinds of protoplasmic fibers extend.
Thesc are the dendrites and the axon.
The dendrites usually extend away from the cell body in one
direction, while the single axon stretohes off in the opporsite direction.
The axon connects with the dendrites of another neuron whose
axon, in turn, connects with the dendrites of another cell.
(In this manner) a chain of neurons is formed that may reach
from the brain to the foot or to any other part of the body.
Along(such) chains of nerve cells the messages (nerve im­
pulses) pass.
The connection between an axon and a dendrite is known as
a synapse.
The simplest type of nervous interconnection within the
body is the reflex arc.
(The reflex arc) illustrates the principle of nervous func­
tion.
The reflex arc is composed of tivo neurons, a sensory neuron
and a motor neuron.
The sensory neuron has a long dendrite, the end of which
lies near the surface of the body.
It(the dendrite of the sensory neuron) extends from there
(near the surface of the body) to near the spinal cord
where it enters the oell body(of the soneory neuron).
The axon of the sensory neuron leaves the cell body and
extends into the spinal cord.

3h9

30o
31.
32.
33.

34.
36.
36.
37.

38.
39.
40.
41.
42.
43.
44.

46.
46*
47.
48.
49.

60.

Within the spinal cord it(the axon of the sensory neuron)
oonneota with a dendrite of the motor neuron.
Th3.s con­
nection is the synapse.
The dendrite of the motor neuron is chort and io almost
immediately connected with its cell body, which also lies
within the spinal oord.
The axon of the motor nerve passes out of the spinal cord
to connect with a musole within the body.
When an appropriate stimulus le applied to the end of the
dendrite near the surfaoe of the body, a nervous impulse
travels a l ong the dendrite from the point of stimulation
to the oell body near the spinal oord.
(The impulse) goes through the oell body to and through
the axon.
At the synaftse It (the impulse) passes to the dendrite of
the motor neuron and passes along It, through the oell
body, and then through the axon of the motor nerve.
At the end of the motor axon It(the impulse) stimulates
the musole to aotfcon. The musole then contracts.
This notion(as described) is purely automatic like push­
ing a doorbell, which initiates the passage of an electrio
current through a wlre.
When the eleotric current reaohes
the doorbell, the bell rings.
The nerves are groups of nerve-cell fibers ..which extend
from the brain and spinal oord to all parts of the body.
The nerves enter and leave both sides of the central
nervous system at intervals.
The twelve pairs of cranial nerves extend from the brain
to various organs in the head region suoh as the eyes,
ears, throat.
The spinal nerves extend from the spinal oord to other
parts of the body.
There are 31 pairs of spinal nerves in man.
Eaoh (spinal) nerve is attached to the spina} oord by two
roots.
The dorsal root (of the spinal nerves) contains sensory
fibers that bring impulses into the oord and the ventral
root oontalns motor fibers that oarry impulses away from
the oord.
The dorsal sensory root has a ganglion oontalnlng the cell
bodies of the sensory neurons.
The spinal oord is composed of two parts, the inner gray
matter and the outer white matter.
The gray matter oontalns the oell bodies of the motor
neurons.
The white matter is composed of cell fibers that extend
up and down the oord.
The white oolor (of the white matter) is due to a fatty
oovering material, oalled myelin, which surrounds eaoh
oell fiber.
The ax>ns of the motor neurons extend out of the cord
within the ventral motor spinal nerves.

350
51.
52.
55.
54.
55.

56.
57.
58.
59.
60.

61.
62.
65.
64.
65.

66

.

67.

68.
69.
70 i
71.

Both th<3 oell bodies and the cl sndritea of those neurons
(motor neurons) lie within the gray matter of the cord.
The axons of the dorsal sensory spinal nerves enter the
cord from the spinal ganglion and may connect dir?etly
with the dendrites of the motor neuron.
Usually, however, there are one or more connective neurons
between (the axons of the sensory neurons and the dendrites
of the motor neurons.
The connective neurons may extend from the senoory axon
to the motor dendrite at the same level and on the same
side of the spinal oord.
They(the oonnectlve neurons) also may extend across the
oord to a motor neuron otf the other side, or they may
go up or down the oord and connect with a motor neuron
at a different level.
Some(oonnectlve neurons) extend up into the brain.
(Thus) nerve Impulses that enter the spina), cord by way
of the sensory nerves may go to any motor neuron within
the oentral nervous system.
(However) none of the Impulses that enter the spinal oord
oes to all of the motor neurons.
omething controls the direction taken by any Impulse,
and this control makes possible Integrated action within
the organism*
If nothing controlled the pathway taken by nerve Impulses,
the varftoue parts of the body would react haphazardly
with no relation to the action of other parte.
Controlled,
coordinated action would be Impossible.
The structure which determines the direction that the
impulse takes Is the synapse.
When an Impulse reaohes a synapse it is either reinforced
or inhibited.
The brain is a large mass of nervous tissue at the anterior
end of the spinal cord.
It (the brain) contains both gray a n d white matter.
The gray matter (of the brain! is composed of cell bodies
and the white matter consist of axons and dendrites.
All of the neurons of the brain are interconnected and all
are connected with the neurone of the spinal cord.
The brain has three major parts, the brain stem, the cere­
bellum and the cerebrum.
The brain stem is made up mostly of axons and dendrites
that extend from the spinal cord to the oerebellum and
cerebrum.
The medulla is the part of the brain stem that connects
dlreotly with the spinal cord.
The cerebellum is a mass of nervous tissue that lies at
the baok of the bsraln over the medulla and behind the cere­
brum.

t

351
71.
72.
73.
74.
75.
76.
77.
76.
79.
80.
81.
82.
83.
84.
85.
86.
87.
88.
89.
90.

91.
92.
93.
94.
95.
96.

The cerebellum lias an .inner branching core of white matter
and an outer oortex of gray matter.
The white matter (of the cerebellum) contains nerve fibers
that connect to oell bodies in the gray matter,
The cerebrum also contains a core of :-liite matter contain­
ing nerve fibers and a cortex of gray matter.
The oerebrum Is divided into two halves, the right and
left hemispheres,
The brain functions in controlling and coordinating the
actions of the entire body.
All voluntary action is initiated in the cerebrum.
One area (of the oerebrum) known as the motor area controls
all muscular action.
Another area (of the oerebrum) Is ooncerned with vision,
another with smell, and another with taste.
Hearing also is dependent on the proper function of a cer­
tain area of the oerebrum.
The oerebellum functions in coordinating muscular action.
In many organisms speolal organs have developed that funct­
ion in receiving stimuli.
Structures that function primarily to receive stimuli are
oalled reoeptors.
External receptors which receive stimuli from the external
environment include the eyes, the ears, the nose, the taste
buds and the sensory areas of the skin.
Internal reoeptors receive stimuli from within the body
and include those in the tendons of the muscles and the
semicircular canals of the inner ear.
The eyes receive light stimuli, which activate nerve Im­
pulses in the optic nerve.
These nerve impulses (in the optlo nerve) when carried
to the oerebrum, result in the sensation of light.
The ears reoelve sound waves, which stimulate nerve impul­
ses in the auditory nerve.
The auditory nerves oarry the Impulses to the brain, whioh
interprets them as sound.
Cells lining the epithelium of the nose are sensitive to
chemical substances that beoome- dissolved in the nasal
fluids.
When stimulated by chemical stbstanoes in solution
In the
nasal fluids nerve impulses go to the brain
by way of the
alfactory nerve and tne brain interprets these impulses
as smell.
Taste is closely linked to smell.
The taste buds are on the tongue and are responsive to
chemical substances in solution.
The skin oontalns reoeptors for touch, pain, pressure,
and the sensations of cold and hot.
The skin reoeptors are looallzed in eertain areas.
It is possible to find them (skin receptors) by touching
the skin in different places with a fine pointed instru­
ment.
The sensation of cold will be perceived only if a oold
needle touches a oold receptor.
It it mioses the oold
receptor, no sensation results unless it is one of
pressure or touoh.

352
9 7 » The same thing lo true
for any of t.lv; otlior .ukln ?.© nc.es
(that Is true for oold ;xoentorsi
98.
The effeotors are the organa of tha body that respond with
action whenever they are stimulated by nerve irpulses.
99.
There are t w o kinds of effectors - muscles and glands,
1 0 0 . There are three kiQds of muscles: skeletal, heart and smooth,
1 0 1 . The skeletal muscles are usually attached to the bones,
1 0 2 . They (the skeletal muscles) work In pairs, one of the
pair pulling a bone one way and the ether pulling It In
the opposite dlreotlon.
103. Skeletal musole Is make up of elongated cells with many
nuolel scattered along the prrlphery of the cell,
104. A musole oell Is also called a muaele fiber;
103. Each (musole) cell has many fine protoplasmic strands run­
ning lengthwise through It,
On these strands are alter­
nating light and dark areas.
Since these light and dark
areas correspond In position In all of the ostran&s In the
oell, the entire cell looks as though It had oross striatlons on it.
For this reason it is sometimes called stria­
ted muscle,
106. Eaoh musole is made up of many (of these) cells, some lying
side by side and some end to end,
107. The (musole) oells are held together by connective tissue
that continues beyond the muscle cells at eaoh end to form
a tendon,
108. The tendon is a tough cord of oonnectlve-tiasue fibers
and attaches the muscles to bone.
109. When a musole contracts, the muscle cells shorter, and
this shortens the entire muscle and pulls on the tendons
attached to eaoh end.
110. Usually one end (of the muscle) remains fixed while the
other end moves.
111. Every muscle in the body oontalns one or more nerve endings.
112. The nerve endings (in muscle cells) are the ends of nerves
that bring nerve impulses from the central nervous system.
113. A musole oontraots normally only when a nerve impulse is
discharged into it.
114. The heart is composed of oardlao muscle.
115. The (musole) cells (in the heart) are striated like skeletal
musole but they differ in that individual cells are branched
and eaoh oell has one nuoleus.
116. Heart muscle oontraots rhythmically.
117. Heart muscle can contract without nervous stimulation,
though there are nerve endings in the heart.
118. The nerves that supply the heart function mainly in con­
trolling the rate of heart beat.
119. One type of nerve carries impulses that stimulate the heart
to beat faster, and another type carries impulses'that stimu­
late it to beat more slowly.
120. The walls of the body tubes suoh as the digestive tract, blood
vessels, and bladder are composed primarily of sheets or
smooth musole tissue.

353
121c
122.

123.
124.
125.
126.
127.
128.

Those (smooth) ipusole cells tire not striated °nl seeh
oell has but one nucleus.
Each (smooth iauecle) oell
tapers at the ends.
Nerves also oonnect w ith smooth muscle (cello).
Glands are composed of epithelial cells which produce
particular substances that have a definite function In
relation to maintaining life functions.
The digestive glands that secrete digestive enzymes are
examples (of glands).
Glands may be one-celled or many celled.
(Glands) may secrete their substances into a tube and
then Into some speolal organ or they may be without tubes
or duots and seorete directly into the blood stream.
The endoorlne glands a r e without ducts and, hence, are
frequently oalled ductless glands.

PRINCIPLE IV
Nervous tissue has the capacity to "store up" the effects
of previous reactions to stimuli.
This oapaolty is basic
to the establishment of Instincts, habits and memory In
animals.
1.
2.
3.

4.
5.
6.

7.
8.
9.
10.
11.

12.
13.

Coordinated actions constitute behavior.
The nervous system works as a unit and coordinates all
of the actions of the body.
Much (of this) integration Is automatic and is the re­
sult of inheritance, while some kinds of coordination are
learned.
The Inherited type of coordination Is illustrated by the
simple reflex such as the knee Jerk.
If one sits with the lower leg hanging freely, a sharp
tap with a blunt Instrument Just below the k n e o w i l l cause
the leg to Jerk forward.
The Impulses stimulated by the blow travel up the leg along
a sensory neuron to the spinal oord.
Within the cord they
cross a synapse to a motor neuron that carries the Impulses
to the leg musoles, which oontraot and cause the leg to
move.
Other examples of automatic behavior are the vlsoeral re­
flexes that control breathing, the aotion of digestive
tract fluid the heart.
Most of the lower animals depend entirely upon automatic
reflexes to coordinate their responses to environmental
stimuli.
Bees build Intricate honeycombs without learning.
Birds build nest exactly like their ancestors did, even
though they have never seen them built before.
Human Infants suokle at the breast without learning and
they show a fear reaotlon If startled.
They (human Infants) also cry without training.
Learning consists of developing new modes of behavior which
replace Inherited behavior or are superimposed upon it.

3$h
14.

1&.
16.

17.
18.
19.

20.
21.
22.
23.
24.

Every organism starts life with an inherit eel behavior
pattern*
Thle pattern 13 changed Toy learning, cither by
the suppression of the inherited behavior or by the addition tc
it of new types of behavior.
The cerebrum Is essential for this process (of learning).
How the cerebrum works in accomplishing learning, no one
knows for sure, but it involves receiving impulses from
the separate senses and coordinating these into a meaning­
ful whole.
The conditioned reflex offers a d u e to the mechanism of
the learning process.
The ol&ssloal example of a conditioned reflex is that of
salivation in the dog.
Normally a hungry dog will secrete a quantity of saliva
when food is seen or smelled.
This is a reflex which in­
volves the reoeptlon of the stimulus through the eyes or
nose, the conduction of that stimulus to the brain, and
the transmission of the stimulus to the salivary glands.
The glands are stimulated to secrete saliva, which flows
into the mouth.
If a bell is rung at the same time that food is presented
to the dog, he will associate the ringing of the bell
with the ppesenoe of food.
After repeated trials, the ringing of the bell without
the presence of the food will cause the dog to secrete
saliva.
(Thus) a new association of stimulus and response has been
formed.
(This new association of stimulus and response) is a con­
ditioned reflex and also a learned response.
It is believed that almost all learning is dependent on
this basic mechanism.

i

355
AREA

6 - COORDINATION AND ADJUSTMENT
UNIT 2 - Chemical Coordination

It la the purpose of this Investigation to discover the re­
lative importance of the fhcts Included In the Lecture Sylla­
bus for Biological Science.
Eaoh fact Is to be evaluated In
terms of the contribution which you bS>?.leve it makes toward
the understanding of a fundamental principle of biology.
Please Interpret the word "understanding" within the limits
you believe to be inposed by the objectives of general ed­
ucation and the speolflo objectives of the area in which
the principle occurs.
The prlndtpies were taken from the
Study Guide for Biological Science.
You will find the prin­
ciples from eaoh area in the study guide followed by facts
taken from corresponding areas of the syllabus.
Will you
rate eaoh faot aooordlng to the following key ?
Mark space 1 if you believe that knowledge of the faot
is 3A3gajlal to an understanding of the
prlnblple.
Mark space 2 if you believe that knowledge of the fact
Is Qjilte Important to a n understanding of
the prlnolple.
Mark space 3 if you believe that knowledge of the faot
is of average Importance to an understand­
ing of the prlnolple.
Mark space 4 if you believe that knowledge of the fact
I* relatively unimportant to an understand­
ing of the prlnolple.
Mark space 6 if you believe that knowledge of the faot
unrelated to an understanding of the
prlnolple.
THE SPECIFIC OBJECTIVES OF AREA 6, UNIT 1
1. To understand that special chemical compounds called
hormones produced by certain tlesues can modify the
functional activities of other tissues In the animal
and plant body.
2. To realize that hormones act as chemical coordinators
and in conjunction with the nervous system of animals
control and Integrate the life processes of organisms.
3. To understand that hormones Influence behavior In def­
inite ways.
PRINCIPLE 1
Hormones function in the coordination and integration of
life processes, such as metabolism, growth and reproduction,
which require prolonged stimulation rather than the rapid
stimulation characteristic of nervous notion.
1.

Adjustment of an organism to its environment Involves not
only the proper response to external stimuli, but also the
coordination of activities within the body.

356
2c
3.
4.
5.
6.

7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.

19.

80.

21.
22.

The sense organs and certain effect;ore and the central
and peripheral nervous system take care of the adjustment
of the whole organism with Its external environment.
The autonomic nervous system and the endoorone eyetem
coordinate internal activities.
The autonomic nervous system Is.oohoerned primarily with
th.e mechanical processes such as breathing, circulation,
and peristalsis*
The endoorlne system coordinates the chemical processes.
Examples of these ohemloal activities (coordinated by the
autonomic system) include the oxidation of oarbohydrates
for the release of energy, the maintenance of the proper
amount of calolum in the blood and the stimulation and in­
hibition of the growth processes.
In general, endoorlne responses are slow, cumulative ones
whioh stretoh over considerable periods of time in con­
trast to nervous responses which are almost instantaneous.
The endocrine "system is made up of several glands.
(The endoorlne) glands have no ducts.
(The endocrine) glands secrete ohemloal substances directly
into the blood that flows through the glands.
The ohemloal substanoes secreted by endocrine glands are
called hormonee,
The hormones are oarrled by the blood to all parts of the
body.
The hormones affect only certain organs of the body.
In these organs (affected by the hormones) they produoe
a specifio type of reaction.
There are many different hormones, and eaoh hormone usually
produces one kind of reaction,
The action of the hormone secretin illustrates the way in
whioh hormones coordinate chemical processes in the body.
Secretin coordinates the action of parts of the digestive
system.
The stomach mixes hydroohlorio acid with food and digestive
enzymes and eventually forces this mixture into the small
intestine.
The pancreas secretes digestive enzymes into
the small intestine, where they digest the food
If these two activities, the entrance of the food into the
small intestine and the secretion of the digestive enzymes
by the panoreas, oooured at different times, the food and
the enzymes would not mix and digestion would not take
place.
A hormone, secretin, coordinates the two events
so that they occur approximately at the same time.
The hydroohlorio a d d from the stomach stimulates the cells
of the small intestine to produoe seoretin, which passes
into the blood stream and is oarrled to the heart and then
to all parts of the body including the panoreas.
Here (in the panoreas) the seoretin stimulates the oells of
the panoreas to secrete digestive enzymes that Immediately
pass into the intestine by war ot the pancreatic duct.
The major endoorlne glands of man are the panoreas, thyroid,
parathyroid, adrenal, pituitary, and gonads.

357
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.

33.

34.
35.
36.

37.
38.
39.
40.
41.
42.
43.
44.
45.

46.

The pancreas has tv-: functions.
One is to secrete diges­
tive enzymes and the other is t o secrete a hormone, insulin.
The endocrine part of the pancreas consists of amall islands
of cells scattered among the cells that secrete enzymes.
No ducts lead away from the islet cells, so the hormone is
secreted into the blood capillaries that course through
the pancreas.
A constant supply of islet hormone, insulin, is necessary
for the proper oxidation of glucose in cellular respiration.
Insulin also plays an essential part in the storage of
luoose in the liver.
he disease diabetes results if too little insulin is pro­
duced.
The thyroid is a paired gland that lies near the traohea
in the neck region.
(The thyroid) secretes the hormone thyroxin, which regulates
the rate of metabolism of the body.
The lack of a sufficient quantity of thyroxin in an infant
or child results in cretinism.
Cretins are stunted.
They have short legs and in extreme
cases they waddle when they walk.
Their skin is leathery
and their teeth are defective.
They also are retarded
mentally.
Thyroxin deficiency in a n adult causes an individual to
be overweight and to be mentally sluggish.
The heart rate
is slower than normal and the entire rate of metabolism
of the individual is slower than normal.
One type of goiter is associated with t;hyroxin deficiency.
The production tff thyroxin by the thyroid gland is dependent
upon a sufficient supply of iodine.
When iodine is deficient in the diet, the thyroid gland
produces less thyroxin than normal and also increases in
bulk.
The goiter is the overgrown (thyroid) gland.
An overproduction of thyroxin Increases the basal metabolic
rate.
The individual (with an overactlve thyroid) beoomes irrita­
ble, nervous, and overactive.
The eyes bulge and the heart
beats irregularly.
The parathyroids are usually four in number.
Each (parathyroid) gland is about the size of a pea.
(Baoh parathyroid gland) lies imbedded In or beside the
thyroid gland.
The hormone produced by these (parathyroid) glands is called
parathormone•
It (parathormone) regulates the calcium metabolism of the
body.
Removal of the parathyroids causes the level of blood cal­
cium to go down, which in turn causes the muscles to con­
tract spasmodically.
Death results (following removal of parathyroids) if cal­
cium is not supplied.

f

358
47.
48.
49.
50.
51.
52.
55.
54.
55.
56.
57.
58.
59.
60.
61.
62.
65.

The overproduction of parathormone causes calcium to bo
removed from bones and teeth.
The adrenal glands lie near the kidneye.
(The adrenal glands) have two parts.
One part (of the adrenal gland; is a oentral oore of cells
oalled the medulla.
The other part (of the adrenal gland) is an outer layer
of oells oalled the oortex.
During times of stress such as
in fright or anger the me­
dulla (of the adrenal gland) pours adrenalin into the
blood.
This (adrenalin in the blood during times of stress) stim­
ulates the heart to beat faster a n d causes the liver to
release gluoose.
The Intake of oxygon is lnoreased also.
The net result (of the affect of adrenalin in the blood
during stress is to increase carbohydrate metabolism and
thus to lnorease the muscular effloienoy of the body.
The autonomlo nervous system is oonneoted to the medulla
and stimulates the produotlon of adrenalin.
If the medulla is removed the autonomlo nervous system
takes over its function.
The adrenal oortex produces a hormone, oortln.
Gortln regulates the sodium and potassium level of the
blood and tissues.
The removal of the oortex (of the adrenal gland) inevit­
ably results in death.
The pituitary gland lies at the base of the brain.
(The pituitary gland) is called the master gland because
its hormones regulate and coordinate many of the other
endocrine .glands of the body.
It is believed at the present time that twenty or more
hormones are produced 6y the pituitary gland.
An excess of one of the hormones (from the pituitary)
during early growth stages results in the production of
lants.
Some giants resulting from an excess of one of the pitui­
tary hormones during early growth stages) attain a height
of nine feet.
The growth of these(pituitary)giants is symmetrical.
If the excess of (pituitary growth) hormone produotlon
occurs after normal growth has oeased the individual
develops the fatal disease, acromegaly.
In this disease (acromegaly) the bones of the hands, feet
and face increase in thickness.
A deficiency of the pituitary hormone during early growth
stages results in the produotlon of normally proportioned
midgets.
The intellectual development of such undersized people
(pituitary midgets) is normal.
The pituitary hormones regulate the performance of other
endocrine glands, such as the thyroid, adrenal and sex
gland.

f

65.
66.
67.
68.
69.
70.

71.
72.
73.

74.
75.
76.
77.
78.
79.
80.
81.
82.
83.
84.
85.
86.
87.
88.
89.
90.

91.
92.

T h e y ( p i t u i t a r y hormoneo) control the secretion of milk
by the mammary glands*
They (pituitary hormones) also regulate the metabolism
of carbohydrates, fats and proteins.
The gonads are the reproductive glands, ovaries and testis.
Both (ovaries and testis) produce reproductive cells, but
they also produce hormones,
The testes in the male contain two kinds of tissue.
One
kind Is concerned with the production of sperms.
The other
kind produces the hormone testosterone.
The cells of the testis that produce testosterone are called
interstitial cells.
The normal development of the secondary sex characteristics
in the male is dependent upon the development of testosterone.
The secondary sex characters include all of those physical
and mental traits that are associated with maleness, other
than the gonads, which are primary sex characters.
The ovaries of the female produce an estrogenic hormone.
The ovaries of the female produce progesterone.
The estrogenic hormone Is responsible for the development
of female secondary sex oharaotera.
Both the estrogenic hormone and progesterone play essential
parts In the reproductive oycle.
Plant8 produce hormones that are essential for growth.
Plant hormones are known as auxins.
At the tips of stems, roots and buds and in young leaves
cells divide repeatedly and produce some growth.
However, most growth (In plants) results from the elongation
of cells behind the tip.
This elongation of cells (behind the tip) cannot occur
unless auxin is present.
It (auxin) is produced in the dividing cells, at the tip
of the stems and roots, and diffuses to the cells behind
the tip,
(As a result of stumulatlon by auxin) these cells (behind
the tip) elongate and growth results.
However, if the concentration of auxin is too great (in the
region of elongation), growth is retarded.
Btems can withstand a higher concentratlon(of auxlnc) than
buds.
Roots can withstand the least concentration (of auxin).

PRINCIPLE II
The systems of ohemlcal and nervous coordination are inter­
dependent to a considerable degree.
1.
2.
3.
4.
5.

The autonomic nervous system and the endocrine system
coordinate internal activities,.
The autonomlo system is conoerned primarily with the mechan­
ical prooesses such as breathing, circulation and peristalsis.
The endoorine system coordinates
the chemical processes of
the body.
The autonomlo nervous system is connected to the(adrenal)
medulla and stimulates the produotlon of adrenalin.
If the adrenal medulla is removed the autonomic nervous
system takes over its function.

360
AREA 7 - MAINTENANCE

OF THE

SPECIES

UNIT 1 - Reproduction and Development
It is the purpose of this Investigation to discover the re­
lative Importance of the facts included In the Leoture Sylla­
bus for Biological Science.
Eaoh fact Is to be evaluated In
terms of the contribution whloh you believe It makes toward
the understanding of a fundamental principle of biology.
Please Interpret the word "understanding" within the limits
you believe to be Imposed by the objectives of general ed­
ucation and the speolflo objectives of the area In which
the principle occurs.
The principles were taken from the
Study Guide for Biological Solenoe.
You will find the prin­
ciples from eaoh area in the study guide followed by facts
taken from corresponding areas of the syllabus.
Will you
rate eaoh fact according to the following key ?
Mark space 1 if you believe that knowledge of the fact
is essential to an understanding of the
pr i n c i p le .
Mark space 2 If you believe that knowledge of the fact
Is quite Important to a n understanding of
the principle.
Mark space S If you believe that knowledge of the fact
1. of ...rag, Importance to an understandlng of the principle.
Mark space 4 If you believe that knowledge of the fact
la relatively unimportant to an understandlng of the prlnolple.
Mark space 5 If y o u bfelleve that knowledge of the fact
unrelated to an understanding of the
principle.
THE SPECIFIC OBJECTIVES OF AREA 7, UNIT 1
1.
To understand the processes of cell division and
their blologloal significance.
2.
To realise the significance of the fact that all life
comes from pre-existing life under present environ­
mental conditions.
5.
To understand the essential difference between sexual
and asexual reproduction.
4.
To understand the essentials of the structure and
funotlonlng of the male and female reproductive sys­
tems.
6.
To realise the importance of* hormones In coordinating
the process of reproduction In animals.
6.
To understand the essentials of human development.
7.
To understand the Important features of reproduction
and development In plants.

361

PRINCIPLE 1
New living organisms arise as the product of living
organisms of the same kind.
1.
2.
3.
4.
5.
6.
7.
8.
9.

Organisms age and die, and thus It Is essential that new
Individuals he produced.
Xears ago it was thought that life could arise spontaneous­
ly out of non-living matter, such as worms from putrefying
flesh or frogs from mud.
Now It Is believed that living things come only from other
living things.
The process of producing new individuals Is called reprot*duotion.
Some organisms reproduce sexually end others asexually.
Asexual reproduction consists of the production of two or
more individuals by the division of one.
In some oases (of asexual reproduction) the parent organ­
ism divides into two offspring of equal size.
This is
known as fission.
In other oases the offspring separates from the parent as
a smaller-slzed replica.
This is budding.
There are some other forms of asexual reproduction (besides
budding a n d fission),but all of them are modifications of
the same fundamental mechanism, which is cell division
(mitosis)•

PRINCIPLE II
The basis for all reproduction is cell division.
1.
2.
S.
4.
5.
6.

7.
8.

The process of producing new individuals Is oalled re­
production.
Some organisms reproduce sexually and others asexually.
Asexual reproduction consists of the production of two or
more ''individuals by the division of one.
In some oases (of asexual reproduction) the parent organ­
ism divides into two offspring of equal size.
This is
known as fission.
In other oases (of asexual reproduction) the offspaing
separates from the parent as a smaller-slzed replica.
This is budding.
There are some other forms of asexual reproduction (besides
budding and fission), but all of them are modifications of
the same fundamental mechanism, which is cell division
(mitosis)
Sexual reproduction is similar to asexual reproduction
in that cells separate from the parent to develop into
offspring, but it differs in two respects.
(First), the cells that separate from the parent (in
sexual reprodpotlon) are special cells that go through
an intricate process of development before they are ready
for reproduction.

m

362
9.
10.
11.

12.
13.
15.
16.
17.
18.
19.
20.
21.
22.

23.
24.
25.
26.
27.
28.

29.
30.

.31.

(Second), the two kinds of cells (gnn’etoc)
must unite In
a process called fertilization before offspring can develop.
There are two kinds of reproductive cells.
One Is the
sperm and the other is the egg.
There are a few exceptional cases where the eggs can develop
without union, but .This does not invalidate the general rule
that in sexual reproduction the usual procedure is for sperms
and eggs to unite before development of young can occur.
Gametes are germ* cells (eggs and sperms).
Gametes or germ cells are produced in special organs oalled
o n ads.
he sperms are produced in testes in the male.
The eggs or ova are produced in ovaries in the female.
The sperms are usually small and motile,
The eggs are usually comparatively large and non-motlie.
The sperms and eggs are produced in organs within the body
cavity of the male or female and must be transported to
the outside of the body,
This (transport of gametes to the outside of the body) is
accomplished by ducts or tubes that extend from the body
cavity to a n opening at the surface of the body.
In the male the ducts that transport the sperms are con­
nected directly to the testis.
In the female the ducts do not connect directly to the
ovaries, but open within the body cavity.
In some forms (of female animal) the open end of the tube
is some dlstanoe from the ovary so the egg drops from the
ovary into the body cavity and must be transported within
the oavlty to the open end of the duct that carries:, it
to the outside.
In other (forms of females), suoh as the human being, the
open end of the duct is so olose to the ovary that the
egg normally drops right into the tube.
The union of the sperm and egg is oalled fertilization.
In the prooess of fertilization the sperm penetrates the
egg and the nuclear material of both unite*
The fertilized egg Is called the zygote.
Fertilization is external (outside of the body) in aquatlo
animals suoh a s glsh and in amphibians -(frogs and toads),
which reproduce In the water.
In these forms (fish and amphibians) the males and females
come t o g e t h e r in the water during the mating period.
While
they are t o g e t h e r the female extrudes her eggs into the
water and the male releases his sperms.
This results in
a mixing of the sperms and eggs, during whloh time the
sperms swim to the eggs and unite with them.
Generally only one sperm unites w ith one egg (in the prooesa of fertilization).
Many sperms may attempt to penetrate one egg, but after
one has entered the egg a fertilization membrane raises
from the surface of the egg and prevents other sperms from
entering.
In internal fertilization the sperms and eggs unite within
the body at the female.

f

363
38.
33.
34.
35.
36.

37.
38.
39.
40.
41.
48.
43.

44.
45.
46.
47.
48.
49.

50.
51.
52.

This (Internal fertilization) la usually accomplished by
a mechanism which Infects the sperms Into the reproductive
ducts of the female.
The male usually Inserts the penis into the reproductive
opening of the female and releases the sperms into the
duct, whloh normally branches and leads to the ovaries.
The eggs are released from the ovaries and travel down
the reproductive ducts to meet the sperms coming up.
Fertilisation (internal) occurs within the ducts (of the
female reproductive system)
Inasmuch as the linings of the reproductive ducts are
moist and the sperms leave the male in a fluid known as
semen,, the sperms can move upward within the tube at least
partly by swimming,
(Thus), internal fertilization is fundamentally the same
as external fertilization in that water is the medium in
whloh the sperms and eggs unite.
Only those animals in w h loh there is internal fertilization,
such as reptiles, birds and mammals have become permanent
land dwellers.
The amphibians that live on land part of the time must re­
turn to ponds and streams to reproduce because fertilization
is external and can be accomplished in water only.
Variations in the usual form of eexual reproduction include
hermaphroditism and parthenogenesis.
In hermaphroditism there are no distinct males and femaleB.
Instead (of separate sexes), ovaries that produce eggs
and testes that produce sperm are both present in the same
individual.
(In hermaphroditism) usually two individuals are necessary
for reproduction.
An exchange of sperms occurs between
the two individuals and the eggs of both Individuals are
fertilized.
(However), self-fertilization is sometimes possible (among
hermaphrodites).
In some animals the f emales produce eggs that do not re­
quire fertilization for development.
The development of eggs without fertilization is called
parthenogene sis.
The queen honey bee, (for example), produces eggs that
may or may not be fertilized.
If the eggs (of the queen honey bee) are fertilized, they
develop into females.
If they are not fertilized they
develop into males.
In aphids two kinds of females develop.
One kind produces
eggs that require fertilization for development to take
place; the other kind produces eggs that develop without
fertilization.
Human reproduction is sexual.
The male produces the sperms
and the female produces the eggs or ova.
The primary reproductive organs of the male are the two
testes.
The testes lie within the sorotum suspended from the lower
abdomen between the legs.

36U
53.
54.
55o

36

.

37.
36.
39.

60.
61.
62.
63.
64.
65.

66

.

67.

66

.

69.
70.
71.
72 V
73.
74.
75.
76.
77.
78.
79.

Eaoh testis oontalns a mumber of colled t ubules In which
the sperms are produced.
The walls of eaoh tubule (in the testes) contain repro­
ductive cells In various stages of development.
The (Immature sperm) cells near the outer edge (of the
tubules) are the least developed, those lying at the Inner
surface near the cavity of the tube are the most developed,
and the cells In between are at various Intermediate stages.
The undeveloped germ cells are more cr less spehrloal and
have the normal amount of cytoplasm.
The undeveloped germ cells have the full complement of
chromatin material.
When the reproductive cells are fully matured they have
lost most of their cytoplasm and half; or approximately
half of the ohromatln.
The details of the ohromatln lose (during maturation) are
Important to heredity.
The mature male reproductive cell Is known as the sperm
cell.
It (mature sperm) has a head containing the ohromatln
tightly packed Inside, a middle piece containing a spiral
filament, a n d a long tall oomposed of oytoplasm.
The head (of the mature sperm; is oval as seen from the
top or bottom and flattened as seen from the side.
In eaoh testis the tubules containing the sperms converge
toward one side Into a network of small tubes.
From this netword (of small tubes) a number of small ducts
lead out of the testis and Join the sperm duct.
The sperm d uctr. passes upward Into the abdominal cavity.
Within the abdominal cavity it (sperm duot) curves forward
to meet the sperm duct from the other testis.
Just before the union (of the sperm ducts) a duot from
a seminal vesicle opens Into eaoh sperm duct.
The fluid /secretions of the two seminal vesloles make
up part of the semen.
The semen is a fluid in whloh ejaculated sperms are Immer­
sed.
The two sperm ducts open into the urethra.
The urethra passes through the penis and. opens at the end.
The prostate and bulbo-urethral glands sSerete fluids Into
the reproductive duota.
The secretions of the prostate and bulbo-urethral glands
added to those of the seminal vesicles make up the semen.
The prostate gland lies at the Juncture of the sperm duots
and the urethra.
The bulbo-urethral glands lie along side of the urethra.
The sperms produced in the testes pass through the small
tubules Into the epididymis.
The sperms remain in the epididymis until ejaculated.
When this (ejaoulation) ooours they pass through the sperm
duot and then through the urethra to the outside.
(When ejaoulation ooours) fluid from the seminal vesloles,
prostate, a n d bulbo-urethral glands is added as the sperms
pass these glands.

365
Each ejaculate la said to contain 200 to 300 million sperms.
The female reproductive system consists of ovaries and re­
productive ducts.
82.
The two ovarlesof the female are flattened,oval bodies
about a n Inch in length.
83.
The ovaries lie attached to the side wall In the pelvic
region of the abdominal cavity.
84.
Eaoh ovary is filled with connective tissue cells and eggs
In various stages of development.
85. An epithelium of undeveloped reproductive cells covers the
surface (of eaoh ovary).
86. At Intervals groups of the epithelial oells sink into the
connective tissue of the ovary.
One of them (epithelial
cells) becomes the reproductive cell while the rest clus­
ter about It and become follicle cells.
87.
The reproductive cell Increases in size while the follicle
oells Increase In number and form a large ball of oells,
the follicle.
88.
A fluid filled cavity appears within the follicle;
The
reproductive cell lies on one side of this cavity surround­
ed by a group of follicle cells.
89. Growth of the follicle continues while It moves Into the
ovary and then back toward the surface (of the ovary).
90. It (the follicle) eventually reaches the surface, from
whloh It projects as a bulge.
It Is now a mature fol­
licle and the reproductive cell Is ready to be released.
91.
In the female the reproductive ducts consists of a vagina,
a uterus or womb and two oviducts.
92. The vagina Is a tube about three Inches long which opens
at the surface of the body at one end and connects with
the uterus at the other end.
93. The uterus is also about thr?e Inches In length.
It Is
a pear-shaped organ with thick, muscular walls and a glan­
dular lining.
94. The cervix Is a projection of one end of the uterus Into
the vagina.
95. At the opposite end of the uterus from the cervix, two
oviducts lead off to the ovaries.
96. The oviducts do not connect directly to the ovaries but
lead into the body cavity adjaoent to them.
97. Finger-llke processes surround the open ends of the ovi­
ducts, some of whloh attach directly to the surface of
the ovary.
98. The disoharge of the female reproductive cell, the egg,
from the ovary Is known as ovulation.
99.
(When ovulation occurs) the follicle ruptures and the egg
Is squeezed out.
100. (After ovulation) the egg Is drawn Into the open end of
the oviduct almost Immediately, apparently through the
action of cilia or hair-like processes that line the walls
of the oviducts and beat toward the uterus.
101. In the human female ovulation begins at puberty, about the
fourteenth year, and ends at menopause, about the fortyseventh year.
80.
81.

366
uenerally one egg ie released each month between these
years (Of puberty and menopause).
The two ovaries alternate Irregularly in producing ma­
ture eggs.
Sometimes two or more ova are expelled at one time and
If fertilised produce fraternal twins or triplets.
After t h e egg leaves the folliole the oells that line
the folliole Increase In number and develop into a large,
yellowish, glandular structure known as the corpus luteum.
If pregnancy ooours the corpus luteum persist until the
3atter part of the pregnant period.
If no pregnancy ooours the oorpus luteum degenerates in
about two weeks.
The egg moves down the ovlduot toward the uterus.
If the egg Is fertilised It begins development Into an
embryo and travels to the uterus, where It remains until
development Is complete.
If the egg Is not fertilized It degenerates before reach­
ing the uterus.
The human egg looses Its ability to be fertilized within
a relatively short time after' ovulation.
The aot of placing the penis of the male into the vagina
of the female Is ooltus or copulation.
The purpose of copulation Is to lntroduoe semen Into the
vagina.
After the sperms are deposited In the vagina, they may
be drawn Into the uterus within a minute or two by the
muscular action of the oervlx.
The sperms move through the uterus Into the oviducts.
If ovulation has oooured. a sperm meets and fertilizes
the egg In the upper part of the ovlduot.
Sperms retain their vitality within the oviducts usually
for no longer than one or two days.
In the human female uterine bleeding known as menstruation
ooours at Intervals of four weeks.
Menstruation occurs In other primates as well (as In humans).
Menstruation begins (in humans) between the twelfth and
fourteenth years and continues until the menopause.
The duration of any one menstrual period varies from one
to fls?e days.
The average Interval between periods Is twenty-eight days.
There Is no exact regularity in the Interval between per­
iods.
The onset of menstruation oolnoldes with the beginning
of ovulation at puberty.
The cessation of both menstruation and ovulation usually
ooours simultaneously at the menopause.
Cases are known where ovulation has oooured after the
menopause.
The relation of ovulation to menstruation Is not mere
oolnoldenoe.
Both ovulation and menstruation are Intimately linked In
a series of events related to the reproductive function
of the female.

367
129.

130.
131c
132.
133.
134.
135.
136.
137.
138.
139.
140.
141.
142.
143.

144.
146.
146.

147.
148.

We may consider the menstrual oycle as beginning when the
pituitary gland that lies at the base of the brain secre­
tes a hormone that stimulates the development of a follicle
within the ovary:,
If the pituitary gland Is removed the ovary ceases to pro­
duce reproductive cells.
As the follicle (In the ovary) develops It produces an
estrogenlo hormone.
The estrogenlo hormone Is carried by the blood stream to
the uterus, where It acts upon the uterine lining.
The estrogenlo hormone causes the lining of the uterus
to grow and develop.
The growth and development of the uterine lining Involves
a thickening of the lining and an Increase In the number,
size, and secretory activity of the glands.
Under the stimulus of the estrogenlo hormone the glands
seerete a nutritive substanoe which fills and dilates
them.
Blood vessels bring a ooplous supply of blood to the lin­
ing of the uterus during the period of the thlokening of
Its walls.
The pituitary gland produces another Important hormone,
the luteinizing hormone.
The luteinizing hormone directly affects the development
of oorpus luteum tissue.
The corpus luteum tissue replaces the folliole after
ovulation.
The ooouranoe of ovulation causes reduction of the supply
of estrogenlo hormone (which hks been providing the stim­
ulus for uterine development and thickening).
With the reduction In the supply of estrogenlo hormone,
another hormone, progestrone, carries on the work of stim­
ulating the development of the uterine lining.
Progesterone is produced by the newly formed corpus luteum.
If the egg produced by, the ovary is not fertilized the
oorpus luteum maintains its production of progesterone
for about two weeks, after which It degenerates and ceases
its endocrine function.
As a result of the absence of the oorpus luteum hormone,
the arteries that carry blood to the lining of the uterus
constriot.
The constriction of the arteries to the uterus stops the
flow of blood and outs off the supply of food and oxygen
to the tissues of the uterus.
As a consequence of the lack of food and oxygen, the cells
of the uterine lining degenerate, they begin to slough off,
blood vessels rupture, and the bleeding and destruction of
the uterine lining begins.
The menstrual flow continues from one to five days, after
which It ceases and the lining of the uterus is repaired
to begin the oycle all over again.
The geglnnlng of repair oolnoldes with the development of
a f?«w follicle in the ovary and the renewed produotlon of
estrogenlo hormone.

368
149.
150.

NOTES
151.
152.
166.
154.
155.
156.

157.
158.
159.
160.
161.
162.
166.
164.
165.
166.
167.
168.

The estrogenic hormone stimulates the repair of the uterus.
During the growth of the ovarian follicle* the eotrdgenio
hormone stimulates the development of the uterine lining*
so that it beoomes gorged with the nutritive seoretlon of
the uterine gland.
AT THIS POINT PLEASE TURN TO THE NEXT A N S W E R SHEET AND
CONTINUE WITH NUMBER 161.
When the egg is released from the ovary* the corpus luteum
hormone takes over and keeps the lining of the uterus in
condition while the egg travels down the ovlduot.
If the egg is fertilized in the oviduct it begins to develop
into an embryo that passes to the uterus and there beoomes
attached to the wall.
The embryo uses energy for growth and development and
lacking a n adequate supply of yolk* it must find its nourish­
ment else where.
It finds it in the lining of the uterus.
The nutritive material secreted by the glands nourishes the
embryo* whloh at first attaches to the uterine wall and
later sinks into it.
The periodic growth and development of the uterine lining
coincides with ovulation* with the result that the young
embryo has a favorable environment in whloh to develop.
The timing of the development of the uterine lining so
that it coincides with the release of the egg and the de­
scent of the embryo is the function of the estrogenlo hor­
mone and progesterone.
If no pergnanoy ooours, the uterus looses its developed
lining and starts all over again to be ready for the next
ovulatifcn.
If pregnancy does oocur* the oorpus luteum continues to
produoe its hormone long enough to Insure the establish­
ment of the embryo within the uterus.
Plants reproduce in the same manner as animals* that is*
asexually and sexually.
Fission ooours in the unicellular algae and bacteria.
Budding ooours in yeast.
Some plants* suoh as the strawberry* send out long, leaf­
less stems or runners* whloh develop roots and separate
from the parent plant.
The potato is a tuber cr underground stem that will pro­
duoe a: new plant when planted.
Practically all plants develop spores or small oells with
a protective ooat.
(The spores or small oells with a protective ooat)separate
from the parent plant and develop into a new individual
when oonditlons favor growth.
Reproduction Involving sex is found in almost all plants.
As in animals* sexual reproduction in plants Involves the
union of two gametes to produoe a zygote which develops
into a new individual.
The flower is the reproductive organ of the flowering plant.

369
169.
170.
171.
172.
173.
174.
175.
176.
177.
178.
179.
180.
181.
182.
183.
184.
185.
166.
187.
188.
189.
190.
191.
192.
193.
194.
195.
196.
197.
198.

The flower la attached to the end of the stem.
The flower conBlste of sepals, petals
stamens* an d the
pistils.
The sepals are usually green* leaflike structures which
encloee the base of the pe tale at their point of attach­
ment to the stem.
The petals are modified leaves.
The petals may he white or colored.
The petals are attached at the end of the stem In the
form of a circle Just within the attachment of the sepals.
The stamens form a circle within the petals and around the
pistil.
The pistil occupies the center of the stem end.
The parts of the flower concerned directly with reproduct­
ion are the stamen and the pistil.
Each stamen has two parts: the anther and a long upright
support, the filament, which holds the anther aloft.
The pistil Is usually flaskehaped, having a bulbous base,
the ovulary, from whloh tthe necklike style projects upward.
The tip of the style Is called the stigma.
The ovulary contains one or more ovules.
In eaoh ovule a reproductive structure develops.
The reproductive structure that develops In the ovule con­
tains a number of cells, the most Important of which are
the endosperm cells and the egg cell.
The anther oontalns cells that develop Into pollen grains.
Eaoh pbllen grain consists of a generative cell and a tube
cell and Is ooverdd by a drought-resisting ooat.
When the pbllen grains are mature the anther breaks open
and the pollen is freed.
The wind blows the pollen of some flowers to other flowers.
In other plants visiting Insects beoome covered with the
pollen and transport it to other flowers.
When the pollen reaches a flower, some of the grains land
on the stigma of the pistil.
This Is known as pollination.
Following pollination the tube cell of the pollen begins
to grow downward Into the stigma and through the style
until It reaches the center of the ovule.
The tube nucleus moves along the pollen tube Just behind
the growing tip.
The generative cell follows the tube nucleus through the
cytoplasm of the pollen tube.
The necleus of the generative cell divides, producing two
nuclei whloh become the male gamete nuclei.
When the pollen tube reaches the ovule, the end of the
tube ruptures and some of its oontents enter the ovule.
One of the male gamete nuclei unites with the egg to form
the zygote.
This is fertilization.
The other male gamete nucleus unites with the endosperm
nuclei.
The zygote develops Into the embryo.
The outer layer or layers of the ovule develop Into the
protective coverings

199.

200a
201.
202.
203.
204.
205.
206.
207.
208.

The embryo and the endosperm surrounded by iho r.rotectlve
covering oomprlae the seed.
The embryo la composed of one or two lar^e embryonic leaves
(the cotyledons), one embryonic root and one embryonic stem.
When the seed Is mature and environmental conditions are
favorable It will germinate.
Germination Involves growth and development of tho embryonlo
root into the ground and growth and development of the
embryonlo stem Into the air above the ground.
Growth of the embryonlo plant requires energy which is
obtained from food stored In the embryonlo leaves.
The cotyledons or embryonlo leaves are thick with stored
food whloh Is digested by enzymes.
After digestion the food Is transported to the growing
root and stem, where It is used for energy and building
of protoplasm.
Development of both roots and stems Involves the differen­
tiation of embryonlo (merlstem) tissues Into the mature
tissues found In adult roots and stems.
The adult tissues of the plant include parenchyma, xylem,
phloem and supporting tissue.
Leaves develop on the stem (of the plant).

PRINCIPLE III
There is an Inverse relationship between the number of
reproductive elements produced by an organism and the
degree to whloh the offspring are proteoted and cared
for.
(No material In the assignment from the syllabus for
this area)
PRINCIPLE IV
The embryonlo development of any organism is directed
by the Interaction between the kind of protoplasm of the
organism and the lntrlnelo and extrlnslo environmental
factors.
1.
2.
3.
4.
5.
6.

The fertilised egg or zygote develops by a process of oell
division, growth and differentiation into a new Individual.
Pood Is necessary to supply materials and energy for de­
velopment (of the zygote).
During the ea&y. stages of development the embryo’s energy
requirements are met largely by means of yolk stored In
the egg.
In all animals yolk Is manufactured In the ovary and in­
cluded within the egg prior to fertilization.
Some animals suoh as the fish and the frog have relatively
little yolk, and this is used up during the early stages
of development.
After the yolk Is gone the young eipbryo muet depend on Its
environment for food.

371
7.

8.
9.
10.

11.

12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.

24.

(In forma having very little yolk) r mouth and intestine
develop very early, with the result that they begin to
feed quite early in development on small particles of
food in the water.
Other for m a , (such as reptiles and birds} produoe eggs that
have sufficient yolk to last them throughout their period
of development.,
Some animals, including man and other mammals, produce very
little yolk for nourishment of the embryo.
(In mammals) the problem of nourishing the developing zygote
is solved by the retention of the embryo within the body of
the mother and the development of a temporary organ, the
placenta, that connects the embryo with the tissues of the
mother.
The embryo gets its nourishment directly from the
mother.
Both the mother9s blood stream and that of the embryo flow
into the placenta.
The two blood streams do not unite, but
flow side by side, and food originally eaten by the mother
and carried in her blood stream diffuses into the blood of
the embryo to be carried to its tissues.
Mammals have special milk-secreting glands, the mammary
glands, that function to nourish the young after birth.
The mammary glands are located on the ventral surface of the
body.
Embryos obtain the energy they use for growth and develop­
ment by oxidation of food in the same manner as adult organ­
isms.
Cellular respiration (in embryos) could not go on without
a continuous supply of oxygen.
The carbon dioxide produced by embryos must be excreted.
In aquatic animals whose young develop in the water, the
oxygen (required by the embryo) comes(directly) from the
water and diffuses into the oells of the embryo.
Eventually gills develop in aquatic animals, but prior to
their development the oxygen diffuses from the surrounding
water directly into eaoh individual oell.
Carbon dioxide diffuses out of the oells (of aquatio em­
bryos) into the water.
In land animals suoh as birds and reptiles, the
;eggs are
not Immersed in water but are laid on land.
In land animals the air of the atmosphere isthe source
of oxygen and the place of disposal of carbon dioxide.
The eggs of birds and reptiles are surrounded by a porous
shell that permits the air to enter and leave the egg.
In the earliest stages of development (of the land egg)
the oxygen of the air diffuses directly into the cells
and the carbon dioxide diffuses out, but eventually a res­
piratory organ develops that serves to receive oxygen for
the embryo from the atmosphere and to remove the carbon
dioxide.
This (respiratory)structure (in the land egg) consists of
a sac-like membrane that grows out of the embryo and comes
to lie Just beneath the porous shell.
Blood vessels of the
embryo carry blood to and away from it. Uhile the blood flows
through the membrane, oxygen diffuses into it from the air
and carbon dioxide diffuses out.

372
25.
26.

27.
28.
29.

30.
31.
32.
33.
84.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.

The saclike membrane (under the shell of the 1'uiu ©gg)
is also a receptacle for the disposition of other Haste
products.
When the young bird or reptile hatoh?s, the membrane (be­
neath the shell) Is separated and discarded.
In mammals, among which the young develop within the body
of the mother, the saclike membrane starts to develop, but
it never beoomes funotional.
In mammals the placenta serves as the respiratory organ
for the embryo.
In mammals, the mother's blood, which flows into the pla­
centa, oarriesoxygen as well as food and this oxygen dif­
fuses into the embryo's blood stream.
Carbon dioxide dif­
fuses into the placenta In the opposite direction.
All developing embryos produoe waste materials other than
oarbto dioxide and these must be removed from the body.
In aquatic animals waste diffuses out of the embryo into
the surrounding water.
In birds and reptiles the saclike membrane (just beneath
the shell) serves as a receptacle for such (metabolic)
wastes.
In mammals the placenta serves to permit wastes in the
embryo's blood stream to pass into the m o t h e r Da blood stream.
The kidneys of the mother excrete (the metabolic wastes
from the embryo's body).
All animal embryos, from the simplest forms to the most
complex, must develop In water to prevent dessioation and
to Insure that pressures will be equal from all sides.
Normal symmetrical development would be impossible unless
the pressure of the environment were equally distributed
over the s urfaoe of the embryo.
The buoyant action of water plus its fluidity makes it an
Ideal medium for maintaining equal pressures.
Land animals do not develop in ponds and streams, but they
too develop surrounded by water.
Early in development to all land animals including reptiles,
birds and mammals, a saollke membrane grows out and sur­
rounds the embryo.
This sao Is oalled the amnion.
The amnion fulls with water and immersed in this water Is
the embryo.
It Is the "bag of waters" that burst prior to the birth of
the human child.
The outer oovering of the zygotes varies in different ani­
mal forms.
Many fish have no covering of any sort over their fertilized
eggs.
Frogs,toads and other amphibians seorete a Jelly-like sub­
stance that swells in contact with water and serves as a
roteotlve layer for the early stages of development,
eptile eggs are covered with a leathery shell.
Bird's eggs have a hard, brittle shell.
Mammals do not have a protective cover immediately sur­
rounding the zygote, but the embryo develops Within the
body of the mother, which serves ably as a protective cover.

S

373
48.
49*

50.
61.
52.
53.
54.
65.
66.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.

The firet step In the development of a human embryo 3.3
fertilization*
The sperm unites with the egg in the uorer third of the
oviduct.
The fertilized egg is called the zygtte,
After fertilization, the zygote continues to move down the
oviduct to the uterus.
During its passage down the duot It (the zygote) goes
through a process of cell division,
The first division of the zygote results in the formation
of two cells of equal size.
These divide in turn to pro­
duce four oells.
By the time the embryo has reached the uterus repeated cell
divisions have resulted in the formation of a ball of oells,
all approximately equal in size.
A cavity appears in the center of the ball of cells, which
is now oalled a biastula.
The blastula differentiates at this time into an inner cell
mass and an outer layer of cells.
The outer layer of cells forms a hollow sphere within whloh
the inner cell mass is suspended.
The inner cell ma&s eventually gives rise
to the body of
the human embryo and the outer cell layer develops Into
membranes surrounding the embryonlo body.
Poon after entering the uterus the embryo attaches itselt
to the wall of the uterus.
The point of attachment (of the embryo to the uterus) varies,
but usually it occurs high on either the front or back wall.
This (attachment of the embryo) happens on the ninth or tenth
day after fertilization.
It is suspected that the embryo secretes an enzyme that
digest the uterine tissue, for' the wall of the uterus dis­
integrates beneath the embryo.
The embryo promptly sinks Into the depression so formed.
It takes about one day for the embryo to penetrate completely
into the wall of the uterus.
A d o t fills the depression above the embryo, which is now
effectively sealed in.
Disintegration of the uterus continues (until) the embryo
becomes surrounded with digested uterine tissue, which is
absorbed and used to nourish the growing embryo.
Up until the time the embryo penetrates the uterine lining,
it remains the same size as the original zygote.
This (failure of the embryo to increase in size) is due to
the limited amount of food the original egg contained.
Upon entering the uterine wall (the embryoJ begins to grow,
obtaining its nourishment from the dissolved uterine lining.
As it (the embryo) growsj it continues td destroy the tissue
around it and expands into the space thus provided.
Qastrulation Involves the differentiation of the inner cell
mass into endoderm and ectoderm.
The endoderm is formed when the outer layer of cells separates
from the rest of the inner cell mass.

37k
73.

74.
73.
76.
77.
78.
79.
80 1
81.
82.
83.
84.
85.

86

.

87.

88

.

89.
90.

91.
92.

93.
94.
95.

The ectoderm dif fe-ontiatea at t'vi car/. i,j' •?
tUo endoderm) and is made up of the cello rer;aInlnj after the endoderm has split off.
The endoderm forms a hollow sphere that, reirainn attached
to the inner cell mass along the surface from which it
separates.
This endodermal sphere is called the yol3i arc.
The ectodermal cells of the inner cell mass hollow out so
that two hollow halls of cells lie afljncont to each other.
The area where the ectoderm lies next to the endoderm is
known as the embryonlo disc.
The embryonic disc is a ciroular dlsc~chnped structure com­
posed of the two layers, ectoderm and endoderm.
The human embryo and eventually the human infant develops
from the embryonlo dlso.
The ectoderm that extends outward and upward from the em­
bryonic dlso arohes over it (embryonic disc) to form a dome­
shaped roof.
The eotoderm forming the roof over the embryonic disc is
the amnion.
The cavity within the amnion is the amnlotio oav ity.
A third layer of cells, the mesoderm, develops within
the embryonic dlso between the ectoderm and the endoderm.
The mesoderm spreads out, covering the ectoderm of the
amnion and She endoderm of the yolk sao.
The placenta functions as an organ of exchange between the
m o ther’s blood stream a n d that of the embryo.
Food and oxygen pass from the m o t h e r ’s blood into the blood
of the embryo, while waste move in.the opposite direction.
The placenta is composed of two parte, embryonic rnd ma­
ternal.
As the outer cell layer (of the placonta) enlarges, fingerlike projections, known as villi grow out rfrom its outer
surface into tfche uterine spaces formed by the disintegra­
tion of the tissue of the uterus.
Blood tieseels that form in the embryo grow down into the
villi.
Through them the blood of the embryo flows into the
villi and then back into the embryo.
The villi occupy spaces in the uterine wall into which the
mother’s blood vessels empty, and it la here that the ex­
change of food, oxygen and wastes occur.
Other blood ves­
sels drain the spaces.
Thus, maternal blood io carried to
the uterine spaoes and away.
That part of the uterus that contains the blood spaces in
which the villi lie is the maternal part of the placenta.
It will be remembered that early in development the blastula is a hollow sphere of cells.
The inner cell mass is
attached at one point and hangs into the cavity of the
blastula.
A layer of oells, the endoderm, separates from the free
surfaoe of the inner oell mass and forms a hollow sphere
oalled the yolk sao.
The eotodarm, or remainder of the innor cell maos hollows
out to become the amnion.
The point where the two spheres (yolk sc.c and amnion) come
together is the embryonic dlso.

375
96®

(Thus), the embryonic disc is composed of two layers of
oells, the ectoderm and endoderm.
97.
(The embryo develops from the embryonic disc) and the re­
mainder of the tissues, including the amnion, yolk sac,
and outer cell layers, become the membranes that function
in aiding development.
98.
The membranes that function in aiding development are dis­
carded at birth,
99.
During early development the embryonic disc raises upward
relative to the amnion so that a circular groove appears
around Its edge.
Actually the groove Is caused b y the down­
ward growth of the amnion along the edge where It attaches
to the embryonlo disc.
It (the atnnlonT grows downward and
folds under.
100. As it (the amnion) continues folding under, the peripheral
groove deepens and outs under the edge of the embryonlo
dlso.
This Infolding constricts the endoderm into two
parts.
101. The upper part contained within the ectoderm of the embryo­
nic dlso Is the gut, the forerunner of the digestive tract.
102. The lower part (of the endoderm) remains the yolk sao.
103. An outfoldlng of endoderm ooours In the floor of the em­
bryonlo gut Just behind Its attachment to the yolk sac. This
saclike outXoldlng grows into a mass of tissue, the body
stalk, which actually bedomes the umbilical cord.
104. The amnion enlarges as It grows.
As the edges of the am­
nion fold under the embryonlo disc, they form a tube that
extends away from the lower surface of the embryonic disc.
This tube Is oalled the umbllloal cord.
105. The umbilical cord contains the yolk sac and blood Vessels.
106. The umbilical cord connects the developing embryo body to
the villi, which develop into the placenta.
107. (Thus), all food, oxygen, and wastes that enter and leave
the embryo do so through the umbllloal cord.
108. All of the tissues, organs and systems that develop In the
*embryo and make up the adult body come from the three em­
bryonlo layers, the ectoderm, endoderm, and mesoderm.
109. The ectoderm develops Into the nervous system and the outer
M a y e r of skin.
110. From the endoderm Is developed the lining of the digestive
tract and Its glands, the liver and the pancreas.
111. The lungs also develop from the endoderm as an outfoldlng
from the gut.
112. The mesoderm develpps Into the muscles, bones, connective
tissue, blood vessels, and other organs that make up the
bulk of the body and lie between the outer layer of skin
and the Inner lining of the digestive tract.
113. After four weeks of development the embryo Is only a little
over one-eighth Inch long.
114. After four weeks of development the embryo possesses some
fish-llke characteristics.
It has gill slits and a tail.
116. The arms and legs begin to form as small buds on the sides.
116. At six weeks it (the embryo) Is a half-Inch In length, the
arms and legs have grown and the head Is quite large In re­
lation to the rest of the body.
The parts of the head are
bevomlng differentiated.
The gill slits and tall are still

376
117.
118.
119.
120.
121.
122.
123.
124.
125.
126.

127.
128.
129.
130.
131.
132.
133.
134.
136.
136.
137.
138.

By eight weeks the human form la attained though the
length la only about one lnoh.
From this time (attainment of human form) on It (the
embryo)l8 known as a fetus.
Furthur development (of the fetus) consists of growth
and completion of the development of the parte already
formed.
The heart starts beating at five or six weeks.
Birth ooours about nine months after conception.
During pregnancy the growth of the fetus is accomplished
by an enlargement of the uterus;
(The uterus) beoomes approximately fifty times larger
(during pregnanoy) than the original size.
By the ninth month the uterus extends to the lower end
of the sternum.
The other organs within the abdominal cavity are eompressed and displaced as a result of the growth of the
uterus.
The fetus assumes a characteristic position within the
amnlotlc oavlty In whloh the elbows, knees and hips are
flexed, the feet and arms are crossed, the back bent and
the head rests on the ohest and Is turned to one side.
At birth the most common position Is head downward, al­
though the reverse position may be assumen with the but­
tocks near the vaginal opening.
The fetus also may lie orosswlse.
When the fetus Is orosswlse or w ith the buttocks nearest
the vaginal ropenlng birth Is more difficult.
Childbirth ooours approximately 280 days after the last
menstrual period, or at the time of the tenth missed mensIs.
Labor oonsists of a series of contractions of the involuntary
muscles of the uterus.
The contractions of the Involuntary muscles of the uterus
cause the "pains" of child birth.
Contractions of the abdominal muscles assist In forolng the.
fetal membranes, containing the liquid and the child, against
the dilating cervix.
The fetal membranes or "bag of waters" burst and the child
Is extruded.
Furthur uterine contractions after the birth of the ohild
expel the plaoenta and fetal membranes.
(After birth) the umbilical cord Is severed olose to the
ohllds abdomen.
Severing the umbilical cord S e p a r a t e s the o h i l d from the
placenta.
The stump of the cord becomes the naval.

AREA 7 - MAINTENANCE OF THE SPECIES

377

UNIT 2 ••• Heredity
It ie the purpose of this Investigation to discover the re­
lative Importance of the facts included In the Lecture Sylla­
bus far Biological Science.
Each fact la to be evaluated in
terms of the contribution which you believe it makes toward
the understanding of a fundamental principle of biology.
Please Interpret the word "understending* within the limits
you believe to be imposed by the objectives of general ed­
ucation and the specific objectives of the area in which
the principle occurs.
The principles were taken from the
Study Quids for Biological Science.
Xou will find the prin­
ciples from eaoh area in the study guide followed by facts
taken from corresponding areas of the syllabus.
Will you
rate eaoh fact aooording to the following key ?
Hark space 1 if you believe that knowledge of the fact
la essential to an understanding of the
principle.
Mark space 2 if you believe that knowledge of the fact
is quit? i mportant to an understanding of
the principle.
Mark spaoe 3 if you believe that knowledge of the fact
As of average importance to an understand­
ing of the principle.
Mark space 4 if you believe that knowledge of the fact
relatively unimportant to an understandlng of the principle.
Mark spaoe B if you believe that knowledge of the fact
unrelated to an understanding of the
principle.
THE SPECIFIC OBJECTIVES OF AREA 7 t UNIT 1
1.
To understand the meohanlsm of heredity*
2. To recognize the social and economic significance
of the solenoe of genetlos.
PRINCIPLE I
Chromosome behavior and distribution during the maturation
of the g e r m oells determines the number of different kinds
of germ cells a n organism can produoe.
1.
2.
3.
4.
6.

Heredity is the transmission of traits from parent to off­
spring.
In both sexual and asexual reproduction oells separate from
the parent or parents to develop into the next generation.
The oells that separate from the parents and develop into
the next generation represent the only protoplasmic link be­
tween parents and offspring.
It follows that whatever passes from parents to offspring to
cause the development of parental traits in the offspring
must be contained in the germ cells.
The controlling substance that passes from parents to off­
spring is the ohromatln.

6.

Chromatin contains chemicals known as genas which govern
the development of the individual.
7.
In asexual reproduction, suoh as mitotic minary fission,
the single cell divides Into two daughter cells.
Before
dlvldlon takes place the ohromatln is scattered In a granu­
lar form throughout the nucleus.
8.
When division (binary fission) begins the chromatin arranges
Itself so that a number of threads are formed within the
nucleus.
9. The particular number (of threads) that form Is constant
. for any species of organism, but varies among different
s p e o le s .

10. Eaoh thread duplloates itself to beoome a double strand of
ohromatln.
11. The genes are arranged In linear order on the ohromatln
thread, like beads on a string, therefore the duplication
of the ohromatln thread also duplloates the genes.
12. The double threads then shorten and thicken until short,
double rods are formed.
13. These short rods are oalled ohromosomes.
14. While the ohromosomes arc forming, the nuclear membrane
disappears and a spindle forms In the oenter of the oell.
15. The double ohromosomes line up with their long axes parallel
to the equator of the spindle, so that one chromosome Is on
one side of the equator toward one pole and the other chromo­
some on the side of the equator toward the other pole.
16. The double ohromosomes separate, one going to each poke of
the spindle.
17. The oytoplasm constricts in the middle of the oell between
the two groups of ohromosomes, with the result that two
oells are formed.
18. Both daughter bells have the same number and the same kind
of ohromosomes and the same kind of genes.
19. Slnoe genes control the development
of traits .in offspring,
it Is apparent that in this kind of reproduction where the
offspring get exactly the same kinds of genes as were present
in the parents, the offspring beoome exactly like the parents.
20. In sexual reproduction genes from two parents are combined
during fertilisation to produoe the new individual.
21. Thus, In sexual reproduction, the offspring inherit some of
their traits from the father and some from the mother.
22. In order to understand how the offspring Inherit some traits
from the father and some form the mother one must follow the
history of the genes during development of the germ oells
within the parent.
23. The germ oells or gametes are produced in the testis of the
male and In the ovaries of the female.
24. The development of these oells (gametes) Is fundamentally the
same In both sexes (male and female) so far as lte effect on
heredity is oonoerned.
26. The part of maturation that Is particularly significant in
heredity Is reduotlon division.
26. The oells In the gonad (dtther ovary or testes) undergo a
division during their development into mature germ oelle that
Is similar to but not exactly like mitoeie.

379
27.
28.
29i
50.

51.
52.

35.
34.
35.

36.
37.

Thus (in reduction division) the chromatin granules form
threads, whloh shorten and thicken into chromosomes as in
mitOBis, but in this oase the threads do not duplicate.
(Instead of duplicating themselves as in mitosis) the
threads (ohromosomes) pair.
In a human oell prior to pairing there are forty-eight
ohromosomes, after pairing there are twenty-four pairs.
(In reduction division in humans) the twenty-four pairs
of ohromosomes line up on the equator of the spindle, the
paired ohromosomes separate, and eaoh member of a pair goes
to the opposite pole of the spindle.
Following separation of the paired ohromosomes the cytoplasm
constricts as in mitosis and two oells are formed.
Eaoh of the new oells (resulting from reduction division)
which contains one chromosome of eaoh former pair, beoomes
a germ oell, either a n egg or a sperm, depending on whether
it is produced by the male or the female.
The primary result of the reduction division is to separate
the paired ohromosomes.
The paired ohromosomes are homologus or alike; that is, they
have genes for the same traits.
If we use the letters A, B, C and D to designate ohromosomes
ah animal having eight chromosomes in a germ oell before
maturation will have two A's, two B ^ . and so forth beoauee
eaoh (kind o f )chromosome has another like it.
During re­
duction division the ohromosomes will pair as follows AA,
BB, OC. DD.
When oell division (reduction division) ooours,
two ceils will be formed, each of whloh will contain A, B,
C, D. This represents the chromosome oontent of a germ
cell.
The same kind of reduction occurs in the produotlon
of gametes by the fcther sex, so its germ oells also oontaln
A, B, C, D.
When fertilisation ooours, the ohromosomes of
the two kinds of germ oells are united and the sygote con­
tains AA, BB, CO. DD.
This is the same number as in eaoh
of the parents, cut half came from one parent and half from
the other.
The illustration of the inheritance of a single pair of
characters (a monohybrid cross) as given in the syllabus,
pages 106-107.
The illustration of the inheritance of two pairs of char­
acters (a dihybrld oross) as given in the syllabus, pages
107-108.

PRINCIPLE II
Genes determine the potentialities of organisms.
The
environment determines the extent to which these potentiali­
ties can be realised.
1.

If a red snapdragon is crossed with a white snapdragon, the
offspring are pink because neither gene of the pair determining
o d o r is dominant.

380
2.
3.
4.
6.
6.
7.
8.
9.
10.
11.
13.
14.

18.
16.
17.
18.

19.
20.
21*
22.
23.

(In snapdragons individuals) heterozygous (for color)
always show an intermediate condition between tho parents
when one pair of genes only is oonoerned.
(A type of inherltanoe similar to oolor in snapdragons)
is
Illustrated in orossea between Negro and white races involv­
ing skin color.
There are genes for black skin and genes for white skin and
none are dominant*
The Pi's
of a black and white cross ere all mulattoes of
the same intermediate shade.
The Pfi's of a black and white oroso show a gradation of oolor
from pure blaok to pure white.
There are two kinds of ohromosomes in every cell of sexually
reproducing organisms.
They are the sex ohromosomes oalled
the X and X ohromosomes. and the autosomes.
The sex chromosomes control development of sex traits, while
the autoeomes control the development of other body (somatic)
traits.
The X ohromosomes contain most of the female determining genes.
The X ohromosomes contain few or no sex-determining genes.
The autosomes eontaln male-determining genes ae well as the
reat majority of genes aggeeting somatic characters,
emales have two X ohromosomes plus autosomes.
Males have one X and one X chromosome plus autosomes.
During development the presence of two X chromosomes in the
sygote results in the development of a female beoause the genes
for the development of the female sex are present in greater
strength than the genes, for:
development of the male sex
in the autosomes.
If a zygote contains X X ohromosomes the male genes in the
autosomes control development and a male results.
The X chromosome has no effect; rather it is the development
of the extra X that makes possible the development of the
male sex.
Occasionally an individual will appear among offspring that
differs from any that have been produced before.
Sometimes the appearance of an offspring that differs from
any that h ave been produced before is the result of the re­
combination of recessive genes and sometimes it is due to
environmental onuses producing a ohange in the ohromosomes
or genes*
Chromosomal or gene ohanges that result in the appearance of
a new trait are called mutations.
Gene mutations are those in which a single gene is involved.
Chromosome changes include large sections of ohromosomes and
involve many genes.
An example of chromosome ohanges is deletion, where a piece
of ohromosome beoomes lost.
The principles of heredity apply to man ae well as to other
organisms.
'

f

24.

25.
26.

27.
28.
29.

30.
31.
32.

33.
34.

36.
36.

37.

38.

The study of human heredity is particularly difficult for
several reasons.
First, there are usually only throe or
four generations of humans produced within the lifetime of
one investigator.
Seoond, the number of human offspring is
Very small compared with the number of offspring produced by
plants and animals,
"bird, individual and social resistanos
act aa barrleas whloh limit experimentation with human mating.
Despite the difficulties, muoh progress has been make (In .
human heredity) and a long list of inherited traits is known.
Some of this information Tabout human heredity) has been
obtained through the study of family histories, which are
Interpreted on the basis of the laws of heredity originally
discovered in other organisms.
Another method (of obtaining knowledge of human heredity) Is
through the use of statistical analysis.
This method (of statistical analysis in the study of human
heredity) Involves observations of the frequency with which a
certain trait appears In a given population(the gene frequenoy)
Geneticist have established certain mathematical formulae by
means of whloh these data (gene frequencies) can be interpre­
ted to indioate the mode of inheritance for a particular trait.
This hypothetical mode of Inheritance is then furthur Investi­
gated by studies of the tmali In closely related individuals.
Tin previous discussions). It has been stated that the pre­
sence of certainepnes is responsible for the development of
oertaln traits In a n Individual.
The aetual relationship between a gene and the trait whloh
it determines, however, has been a matter of conjecture.
It has recently been shown by various workers in genetics
that it Is possible for a single gene to control a single
bloohemloal reaction and that this control is probably due
to a control of the production of enzymes.
(In other words) each gene may produce an enzyme or it may
produoe a substance whloh In turn produces an enzyme.
(These) ensymes regulate the thousands of chemical reactions
which take place In a n organism and it Is conceivable that
a change or cessation of one or more of these chemioal re­
actions would result In variations In the appearance or be­
havior of a n Individual.
Albinism Is an example of a characteristic in man which Is a
result of the failure of a certain chemical reaction to take
plaoe.
One of the amino acids Is oxidized to form a substance called
dopa.
In normal man and women dopa Is converted to a pigment
oalled melanin whloh oolors the eyes, skin, and hair.
Ibis
change from dopa to melanin is attributed to a dominant gene.
The reoesslve gene evidently is unable to complete this
chemical reaotion (dopa to melanin) and, consequently, an
Individual who has two of these recessive genes will be an
albino.
This person (an albino) will have very light skin, white hair,
and pink eyes, beoause of a n almost total lack of pigment in
these structures.

382
39.

40.
41.
42.
43.
44.
46.
46.
4?.
48.
49.
60.

51.
52.
53.
54.
55.

The color of the eyes Is due to granules of pigment de­
posited through the back part of the iris.
Blue oolor is due to granules which reflect blue light.
Brown eye oolor is oaused by the presence of brown pigment
in front of the granules responsible for blue eye color.
Other eye colors (besides blue and brown), such as gray or
green, are due to the varying amounts of brown pigment laid
down on the granules reflecting the blue light.
In the case of individuals where no pigment is pro cent, the
eyes appear pink because of the reflection of the color of
the blood in the blood vessels of the eye.
The exaot mode of inheritance of eye oolor is not known, though
it is thought that several genes are involved.
Brown is generally considered dominant over blue.
It should be appreciated that genes which determine the ab­
sence or presenoe of a oertaln characteristic are often in­
fluenced by genes which determine other characteristics.
Here la a situation (above) where the genes for albinlsqj
inhibit the potential development of eye color despite the
fact that genes for eye oolor are present.
This example (of the inhibiting effect of albino genes) may
give you an insight into the complexities of the interre­
lationships existing between the actions of the &enes.
It la because of the oomplex Interrelationships among genes
that many of the things we would like to know about human
inheritance have not been found out.
Skin oolor is determined by the pigment in the skin.
There Is much pigment in the skin of Negroes and little in
the skin of whites.
In the Negro white crosses the offspring are mulatto and
intermediate in oolor.
When two mulattoes are crossed, the offspring are various
degrees of pigmentation.
It is thought by some geneticist that many pairs of genes
are responsible for the inheritance of skin oolor.
One explanation (for the inheritance of skin color) is that
two Dalrs of scenes are involved.
A black skin results from the genotype AABB and a white skin
from the genotype aabb. A mulatto would have the genotype

AaBto.
56.

57.

58.

The skin of an individual having a genotype Aabb would be
intermediate between mulatto and white and similarly a geno­
type or AABb would result in a skin color intermediate be­
tween mulatto and blaok.
If this hypothesis (for the inheritance of skin color) is
aooepted, it oan also be inferred that the genes are passed
from parent to offspring as they are in an ordinary dlhybrld
oross where there is a lack of dominance in both pairs of
genes.
There are small oolor differences within the white race
which may be oaused by the influence of only a single pair
of genes.
The darker pigmentation apparently is dominant
over the lighter.

383
59.
60.

61.
62.

65.
64.
66.
66.

Some baldness may result from disease, but c.uch of it is a
hereditary characterlatic.
Apparently onepalr of genes ean express itself differently
depending on the sex.
In males the gene is dominant, while
In females It la reoesslve.
Thle type of Inheritance (as In baldness) io fenown as
sex-limited or sex-influenced Inheritance and explains why
more men than women are bald.
In red-green oolor blindness the person cannot distinguish
between red and green colors.
This abnormality (red-green oolor blindness) Is Inherited
as a sex-linked reoesalve.
A sex-linked character Is one In whloh the gdnes are on
the X chromosomes.
The gene for oolor blindness Is recessive to the normal gene;
therefore two genes for oolor' blindness- one on eaoh X chromo­
some- must be present in the female to cause color blindness.
If only one gene Is present (for oolor blindness) in the
female, she is not oolor blind, but Is a carrier, and can
aes the gene on to one-half of her offspring,
he male , on the other haftd, with one X and one Y chromo­
some. will be oolor blind If the defective gene Is located
on the X-ohromosome.
The X ohromosome (of the male) carries no genes for this
trait (oolor blindness).
Since only one gene Is neoessary to cause color* blindness
In males, more males are colorblind than gemales.
If a colorblind man marries a normal woman, all his sons
and daughters will be normal, but one-half of his daughters
will be barriers.
These {carrier daughters) may pass the gene to one-half
of their sons, who will be oolor blind.
A oolor blind man will transmit this trait (colorblindness)
to some of his grandsons through his daughters.
Total o o l o r :blindness Is also hereditary, as is the inability
to distinguish between various pastel shades of oolor.
The mode of lnheritanoe of these types of oolor blindness
(total and pastel) has not been definitely established.
Surveys show that approximately 7 per cent of the white
population Is left handed*
Studies of olosely related Individuals Indicate that there
Is a correlation between the handedness of parents and their
offspring.
When both parents are right-handed, about 6 per cent of the
ohlldren are left-handed.
When pne parent Is right-handed and the other left-handed
about 16 per cent of the ohlldren are left handed.
When both parents are left-handed, about 50 per cent of
the ohlldren are left-handed.
Sinoe two right-handed parents may have left-handed ohlldren
and two left-handed parents may have right-handed ohlldren,
one hypothesis is that handedness is due to a single pair
of genes with laok of dominance.

§

68.
69.
70.
71.
72.
75.
74.
75.
76.
77.
78.
79.
80.

36U
81.

62.

63 .
64.

.
66.
66

87.
88.

89.
90.

91.
92.

93.
94.
96.
96.
97.
98.
99.

According to this hypothesis (that handedness is due to a
single pair of genes with lack of complete dominance) those
Individuals who are homozygous for right-handedness will
he right handed, those homozygous for left handedness will
he left handed.
Heterozygous individuals, however, nay be
ambidextrous, right o r left-handed, depending upon environ­
mental influences, which of oouree, are toward right-handedness
Handedness among homozygous Individuals may occasionally be
changed by environment, but such a change, according to some
psychologist, may result in nervous disorders such as stutter­
ing.
There are at least three blood groups in men, the ABO group,
the MM group and the R h group.
All three blood groups (ABO, MM and Rh) are inherited in­
dependently of eaoh other.
One explanation of the inheritance of the A, B, 0 blood group
is that three genes are involved.
Gene A causes the development of antigen A in the red blood
oorpusole; gene B causes the antigen B to develop; gene 0
causes the development of no antigen.
These three genes (responsible for the ABO blood groups)
are present in the population in general, but any one in­
dividual has at most only two ot the three.
Neither gene A nor gene B is dominant to the other but both
are dominant to gene O.
It has been discovered that the A and B antigens are present
not only in the red blood oells, but also In every oell of
the body.
Experimental work in the field of plastic surgery indicates
that better results are obtained in the grafting of tissues
from one individual to another when these individuals are
of the same ABO type.
Thle may b e due to the same principles
Involved in blood transfusions.
The A and B antigens are soluable In the body fluids.
The degree of solubility (of A and B antigens in the body
fluids;, however, varies with different individuals.
In
about 70 per cent of the population the presence of these
antigens oan be deteoted in the saliva.
(The individuals in which the antigens oan be detected in
the saliva) are known as seoretors, the remainder non-seoretors
The oondition whereby antigens may b e deteoted In the saliva
is inherited as a simple dominant trait.
Under certain olroumstanoee criminal investigators are able
to determine the ABO type of seoretors by analysis of saliva
on recently discarded cigarette stubs.
In the inheritance of the MM group one gene (M) causes the
development of the M antigen while another gene (N) oauses
the production of the N antigen.
Neither of the genes (for M and N antigen)is dominant.
The MN antigens are not known to produce any harmful effeots
as a result of blood transfusions regardless of the MN type
Of the donor or reolplent.
A knowledge of the mode of inheritance of the ABO and MM
blood groups is applied wulte often in cases of disputed
paternity.

385

100 .
101 .
102 .
105.
104.
105.
106.
107.

108.
109.

110

.

.

111

118.
115.

114.

116.

Another of the Inherited blood groups is the Rh complex.
One explanation of the Inheritance of the Rh factor is the
presence of three pairs of genea on a single pair of chromo­
somes.
The six genes (involved in the inheritance of Rh) when
combined in all possible arrangemento produce eight differ­
ent R h blood types.
Although these eight (Rh) types are due to different geno­
types, seven of them are collectively known as Rh + f the
eighth t y p e ,as Rh-.
For the sake of simplicity, however, Rh positive is said
to be Inherited ae a dominant trait and Rh negative as a
reoeealve trait.
Aooordlng to this simplified explanation,, an R h + i n dividual
would have a gfinotype or HR or Rr and an Rh- individual
would hk*e a genotype of rr.
About 66 per oent of the white population is Rh-*- and 16 per
oent is Rh-.
Knowledge of the lnherlt&noe of the R h group is important
because a m a t l n g between an Rh-f- father and an Rh- mother
will produce in at least one-half of the cases, offspring
that are R h + .
The presenoe of an Rh*)~ child within the body of an Rhmother sometimes leads to traglo results.
If the R h + blood cells of the child diffuse into the blood
stream of the mother, they cause in the mother's blood the
roduction of antibodies.
f these antibodies (from the Rh- mother's blood stream)
diffuse back into the Infant's blood stream and come in
oontaot with the Infant's Rh antigen, the red blood cells
of the Infant may be destroyed and the child either dies
or has severe anemia and Jaundice at birth.
The first ohild born of such parents (Rh+ father and Rhmother) usually esoapes harm, but by the time the second
ob third ohild is developing there may be sufficient anti­
bodies in the mother's blood to cause the symptoms des­
cribed above (erythroblastosis) to occur In the infant if
it happens to be R h + •
This disease (Rh disease) known as erythroblastosis foetalls,
has long been recognised, but the oause was not known before
the discovery of the R h antigens.
(As previously mentioned), tne first child born to parents
of this R h combination (Rzw- father and Rh- mother) us­
ually esoapes harm and occasionally the second a n d third
child may ne unaffected.
There have also been oases in which no children (of Rh-ffathers and Rh- mothers) showed symptoms, however, surveys
indicate that about one out of twenty-eight babies born
to such parents show symptoms of this disease (Rh disease).
Of those (babies) showing these symptoms (of R h disease)
some recover without medical attention, others, more severely
affected, may recover with medloal treatment, and a few are
stillborn or live for only a short time.

S

116,
117.
118.

119.
120.
121.
122.

123.
124.
125*
126.

With Increasing kncivledge of the £
hyaleIans
are constantly developing better techniques for I;'.v?* treat­
m e n t of this disease (erythroblastosic).*
The question whether mental ability io inherited has fre­
quently been a sked.
It Is well recognized that the human population varies in
intelligence from the idiot, who never reaches a mental age
high enough to care for himself, to the genius, who presents
the world with great accomplishments in literature, music,
and solenoe.
One thing is.obvious, even if we assume that mental ability
is inherited: environment has a definite role to play.
A potential genius, if completely Isolated from society,
would not develop nls mental capacity to the point where
it would be reoognised as such.
(On the other hand), an individual who hoc a low mental
eapaolty could never beoome a genius oven if he were ex­
posed to a society of the highest academic level.
For this reason (relationship between heredity end environ­
ment) it is almost Impossible to attributo an individual's
intelligence wholly to heredity or to environment; rather
it is a produot of both.
It is probable that heredity setc the limits of rental de­
velopment, while environment aoto within theco :i.U:ita.
Tests have been compiled by psychologist to
in­
telligence*
These tests measure intelligence in terns of nontax age.
By dividing the mental age of the individual by the chrono­
logical age and multiplying by 100, the I. <1., or intelli­
gence quotient, is determined.

i. Q. -

127.

128.
129.
130.
131.

AiBS— — —

x ioo

Chronological Age
The following arbitrary levels of intelligence have been
established on the basis of intelligence quotients de­
termined by these tests (intelligence teste)
Level
X.Q.
genius
140 or over
very superior
120-140
superior
110-120
normal
90-110
dullness
60-90
borderline
70-80
moron
60-70
imbecile
26-60
idiot
0-26
The persons considered mentally deficient or feeble-minded
are classified as idiots, imbeciles, or morons.
Idiots are those individuals who have an I. Q. of 0 - 26.
The mental age (of idiots) is one to two yc?ro.
Idiots are absolutely helpless when it eomoc tofeeding and
oaring for themselves.

387
132.

133.
134.
135.
136.
137.
138.
139.
140.
141.
142.
143.
144.

145.
146.
147.
148.

149.
150.
161.

One type (of idiot) is the microcephalio, or pinhedd, in
whloh the hones of the skull close very o&rly" in the life
of the individual— earlier than in nornaiiy developing
individuals.
This early closure of the sku l l (in microcephalic idiota)
prevents the brain from growing and developing to normal
else and mental capaoity.
Another type of idiot is the cretin.
Cretinism is the result of insufficient thyroid hormone
during early development.
One hypothesis as to the cause of idiocy is purely environ­
mental, attributing the idiocy to faulty prenatal environ­
ment or birth injuries.
Another hypothesis as to the cause of idiocy points to
heredity a n d requires the presence or absence of certain
genes which, when expressed, produce the condition.
She third, and probably the least dogmatic hypothesis as
to the cause of idiocy, Includes both environment and here­
dity. as contributing interacting factors.
A n example of a type of feeble-mindcclness which definitely
is hereditary is phenylketonuria.
In normal individuals, phenylpyrlvic acid, which is one
of the products of metabolism, is oxidized by an enzyme.
In phenylpyruvio Idiots, the enzyme (responsible for the
oxidation of phenylpyruvio acid) is not present and phenyl­
pyruvio aoid is not oxidized and is exoreted in the urine.
The excess of phenylpyruvio acid in the body damages the
nervous system, thus causing ldlooy.
Phenylketonuria is due to a recessive gene which results
in the absence of the enzyme necessary for oxidation of
phenylpyruvio aoid.
Phenylketonuria is an example of a single gene's being
responsible for the production of an enzyme, the presence
or absence of whloh determines normality or feeble-mindedness.
dome feeble-mindedness, higher than idiocy, is also thought
to be due to heredity.
Family histories indicate that this type of mental deficiency
(feeble-mindedness higher than Idiocy) occurs much more fre­
quently in some families than in others.
The study of twins supports the hypothesis that heredity
is the oause of certain kinds of mental slowness.
Studies of twins show that when one fsaternal twin is
feeble-minded, the other is feeble-minded in one-fourth
of the oases: in identical twins, however, when one is
feeble-minded, the other is feeble-minded in practically
every oase.
It is known that superior intelligence runs in families.
It is claimed b y some that superior intelligence is due
to an environment whloh encourages the development.
.
If environment is the sole oause(of superior intelligence!
one would expeot that all children reared in favorable
surroundings would develpp into superior people,
mis,
however, is not the case.

388
152.
155.
154.

155.

156.
157.
158.
. 159.
s

160.
161.
162.
163.
164.
165.
166.

167.
166.
169.

170.
171.

Dullards do appear In favorable environments. though not
so frequently as in other families.
To the geneticist, the segregation of genes is the most
reasonable explanation for the occasional appearance of
dull ohlldren in bright families.
Studies made of children reared in orphanages whore, pre­
sumable, the environment is fairly constant fox* all indi­
viduals, show that ijust as much variability exist among
these orphans a s in children raised in their ov.n homes.
Another test (of the relationship of environment .and here­
dity to intelligence) is the measurement and correlation
of the intelligence of adopted ohlldren and their foster
parents a n d oomparison of the results with those derived
from studies of true parents and their children.
It has been found that there is a closer correlation be­
tween true: parent and true ohild than between foster
parent a n d foster ohild.
Studies of identical t w i n s show that they ar e more alike
in intelligence than fraternal twins even when reared in
different environments.
Insanity la a derangement of the normal mind.
A person of normal or superior Intelligence may become
Insane.
There are some twenty types of insanity; several of whloh
are oonsldered hereditary.
Huntington*s chorea is inherited as an autosomal dominant.
Because Huntington*s ohorea frequently appears late in
adult life, its presence is frequently unsuspected until
after the individual has married a n d reproduced.
Beoause Huntington's chorea does appear late in life after
the normal reproductive period its control is difficult.
Huntington's ohorea is a rare disease.
Hospital records show no more than 100 to 200 cases of
Huntington's ohorea per year in the United States.
The vlotims of Huntington's ohorea exhibit Irregular and
spasmodic movements of the face a n d arms.
Gradually other
voluntary musoles are Involved and the mental functions
either slowly degenerate or the individual becomes
violently insane.
There is no known cure for Huntington's chorea.
Schizophrenia (Dementia Praeoox) lo characterized by melan­
cholia, emotionalism, and delusions of persecution.
Some geneticist claim that schizophrenia is hereditary
and they use a s a basis for their claim the fact that the
frequency of the disease among relatives of affected per­
sons is much greater than in the general population.
A study of twins shows that when one member of a pair
of fraternal twins develops the disease, the other develops
it in less than one-fourth of the oases (schizophrenia).
In identical twins when one member of a pair develops
schizophrenia, both twins develop the disease in nearly
every case.

389

172.

175.

174.
175.

176.

177.
178.
179.

180.

181.
182.

185.
184.
185.
186.

The environmentalist say that Chore is greater frequency
(of schizophrenia) among relatives of affeatcd individuals
because of common environment, common problem© and common
frustrations.
It seems reasonable to assume that mental defects are
determined, in part, by heredity, since mental illnesses
have their basis in the nervous system and the functioning
of the endocrine glands.
Geneticist who have worked on the assumption that schizo­
phrenia Is inherited have postulated that it is transmitted
as a recessive trait.
It is furthur postulated that individuals possessing genes
for schizophrenia will not exhibit symptoms for it unless
they are faoed with certain types of problems and frustra­
tions.
If individuals possessing the genes for schizophrenia should
never be plaosd in an environment where certain types of
problems and frustrations exist, it is believed they may
not develop the disease.
Bpileptlce suffer convulsions with loss of consciousness.
Reoent work indicates that epilepsy is due to a dominant
ens with variable expressivity.
y means of the eledtroenoephalograph (an instrument used
to reoord the eleotrioal pulsations of the brain) it has
been found that all eplleptlos have an abnormal type of
brain wave (cerebral dlsrhythmla) and that
at least one
of the parents will also exhibit this type
of brain wave even
though he may not be subjedt to the seizures.
It is assumed that the abnormal brain wave
is the consis­
tently expressed inherited oonditiQn (due to the genes re­
sponsible for epilepsy), and for come reason, possibly en­
vironmental lnfluenee8, people displaying this abnormality
may or may not exhibit epileptic convulsions.
Our knowledge of genetios has enabled us to improve the
stooke of our domesticated animals and plants to a con­
siderable extent.
There is little doubt from the standpoint of the common
good of society that measures should be taken to control
the spread of known hereditary defects throughout the
population.
Biologist have long advocated the adopton of measures aimed
at opntroling the spread of known hereditary defects through­
out the population as part of an eugenics program.
Biologist have also pointed to the improvement of the
human stook through selective breeding.
Whether the measures of negative or positive eugenics will
be applied is dependent upon the attainment of a degree of
social oonsoiousness which,at present, seemc Utopian.
Before any progress oan be made toward the betterment of
mankind through genetios, society must understand the facts
plaoed at its disposal by scientist and must develop a will­
ingness to use these fadts for the good of society.

t

390
18?,
188.

Through a program of general education society can come
to understand the facts placed at Its disposal by sclenoe,
The development of a willingness on tho part of society
to use faots for Its own good will have to jr.it upon an
advance In our social evolution.

391

AREA Q - INTERRELATIONSHIPS
UNIT 1 - Th© Organism and Its Environment
It Is the purpose of thie investigation to discover the re­
lative importance of the facts included in the Lecture Sylla­
bus for Biological Bolence.
Each fact Is to be evaluate* in
terms of the contribution which you believe it makes toward
the understanding of a fundamental principle of biology.
Please Interpret the word nunderstanding" within the limits
you believe to be Imposed by the objectives of general ed­
ucation and the specific objectives of the area in which the
principle occurs.
The principles were taken from the Study
Guide for Biological Science.
Xou will find She principles
from each area in the study guide followed by facts taken
from.corresponding areas of the syllabus.
Will you rate
eaoh fact according to the following key?
Mark epaoe 1 if you believe that knowledge of the fact
is essential to an understanding of the
principle.
Mark epaoe 2 If you believe that knowledge of the fact
is oulte important to a n understanding of
the principle.
Mark space 3 if you believe that knowledge of t he fact
Is of average importance to an understand­
ing of the principle.
Mark space 4 if you believe that knowledge of the fact
is relatively HalKBjgg.tafl& So an understand­
ing of the principle.
Mark space 5 if you believe that knowledge of the fact
is unrelated to an understanding of the
p r i nciple„
THE SPECIFIC OBJECTIVE3 OF AREA 8 , UNIT 1
1 . To understand the nature of t h e environment of living
things.
2.
To understand that adjustment of organisms to an ever
changing environment is essential if the organism or
speoles is to survive.
S.
To reoognlze that a knowledge of eoologleal principles
increases o n e ’s understanding of human societies.
PRINCIPLE I
The animals and plants living in the same habitat con­
stitute a community of interrelated and interdependent
members. The plant life of the community is the primary
determinant of the character of the community which be­
cause of its characteristics may be considered a super—
organism.
1.
2.

No animal or plant lives a completely independent life.
All organisms are in constant interaction with their
environment and continually respond to environmental factors
in order to maintain themselves.

392
3.
4*
&.
6.
7*
8.
9.

10 f
11.
12.
13.
14.
lb.
16.
17.

18.
19.
20.
21.
22.
23.

The responses or animals are often moz^e immediate and
noticeable than those of plants because of tha higher
degree of organisation in animal forms,,
The basic relation between organism and environment la the
same for both plants and animals.
The environment of a given organism I n c l u d e s the sum total
of the conditions or factors to which it is exposed.
The place or niche that an organism occupies in nature is
called its habitat.
The term (habitat), however, Inoludes only the physical
factors in the environment of organisms and not the organisms themselves.
(In other words) the habitat is t h e physical framework^
that supports in one way or another the living organisms
in a given community.
(For example) the habitat of an oyster population Includes
such physical factors as 1he type of botton, the chemical
conditions of the sea water, the pressure, and light and
temperature conditions prevailing in the area, but does not
include the interactions between the oyster and its prey,
parasites or predators.
Plants and animals are associated in natural units over
the earth.
These (natural)units are called communities or, more speci­
fically. biomeo. and each contains many kinds of habitats.
To the biologist the biome is more than the sum of its
parts.
In a certain sense the blome may be regarded as a kind of
superorganism.
The blome oonoept is an operational concept in that it has
proved useful in furthering our understanding of the inter­
relationships among living things.
The blome is not a static unit, but extremely dynamic.
The growth and development of the blome inoludes all of the
changes bare or denuded areas pass through in arriving at
a condition of relative stability oalled the olimax stage.
The earth can be divided into eight blome types.
These
are (1) tundra and ice, (2) coniferous forest, (3) temper­
ate forest, (4) grassland, (5) desert, (6 ) tropical forest,
(7) temperate rain forest, (8 ) the ooaan.
Each of the major natural units (blome types) produces
characteristic Vegetation.
The vegetation present (in a blome type or natural unit) is
dependent upon climatic and other factors of the environment.
The animal life of the blome is dependent largely upon the
plant life in the area.
Man, in turrl, is dependent upon both plant and animal raw
materials obtained from these natural life areas in order
to Hire and build his industries and institutions.
The major vegetation areas on the earth's horizontal
surface are also evident in the vertical plane, as on high
mountains.
The habitat factors of climate and soil are important de­
terminants of the distribution of plant and animal life.

393
24.
25.

The Interaction of living organisms within the blome con­
stitutes the biotic environment of the Individual organ­
ism or the population.
All of the organisms living within the unit (blome) are
striving to keep ©live and reproduce their kind, the com­
petition for food, shelter, space and mates results In a
w eb of life exceedingly complex in its nature.

P R I N C I P L E II

The feeding relationships between the organisms of the
community constitute the center of a c t i v i t y within the
community.
Other basic pursuits b y t h e organisms of the
oommunity are those Involved In obtaining shelter and
protection from the biotic and physical elements of the
environment, mating, and caring for the young of the species.
1.

One of the most important Integrating factors In the biotlo
environment Is the food chain,
2.
The degree of Interdependence of living organisms Is evident
in the food relationships of the community,
3.
In a typical fresh-water pond the microscopic green plants
or algae reproduce and grow In countless numbers.
4.
The algae (In a fresh water pond) transform radiant energy
Into chemical energy of food by their photosynthetic aotivity
and consequently serve as the haslo source of food for the
community.
5.
Protozoans, microscopic crustaceans, and small Insects feed
upon the algae (in a fresh water pond), and these animals.
In turn, ard fed on by such larger animals as aquatic In­
sects and small fish*
6.
Large fish feed upon smaller fish and large Insects (In a
pond) and finally reptiles, birds, and mammals utilize the
fish as food.
7.
In a food chain such as that In a fresh-water pond, millions
of a l g a e .are required to support thousands of microscopic
animals,oalled key industry forms, which feed upon them.
6.
The thousands of animals, whloh have transformed plant
protoplasm Into animal protoplasm, sustain hundreds of fish,
which In turn support the relatively few fish-eating verte­
brates.
9.
A food pyramid Is established for every food ohain.
1 0 . The food pyramid serves to present the quantitative aspeot
of the food web In a community.
11. Food pyramids are the result of two tendencies: (1 ) that
smaller animals have a higher c a p a c i t y to reproduce them­
selves than do the higher animals, (2 ) that the smaller
animals usually are the prey for the larger animalB.
12. Included as faotors In the formation of food pyramids are
such (faotors) as the size of the food, the amount of food,
the availability of food, and the capacity an animal has
to utilise the food.
13. Organisms expend energy to obtain food and nourishment.

39k
A very large animal occupying the apex of the (food) pyramid •
might he able to maintain itself on amefoa protoplasm, but
the amount of energy required to obtain sufficient numbers
of ameba for this purpose would be altogether out of pro­
portion to the energy yield of the food.
15. Because
of the relationship between energy required to
obtain food and the energy obtained from the food, animals
usually feed upon the next else group in the food pyramid,
thus obtaining the elements in the ameba protoplasm at third
or fourth hand.
16.
There are notable exceptions to this rule (that animals usual­
ly feed on the next size group in the food pyramid) such
as the Whalebone whales and the Mississippi River paddleflsh,
whloh, despite their size feed on microscopic animal and
plant life.
17. Man is the only organism which can feed on any size food.
18. Studies
of fluctuations in animal populations, whether free
living or parasitic, demonstrate that a change in one link of
a ' . given food chain will inevitably Influence all the
organisms involved in the chain.
19.
It is well known that in Canada the arotio fox fluctuates
with the lemmings, the numbers of red foxes fluctuate with
mice and rabbits, the fisher varies with mice, rabbits and
fish, and the lynx populations are correlated with the
numbers of rabbits.
20.
Any factor or set of factors whloh renders the environment
unsuitable for the rodents will seriously Influence the
oarnivoree which prey upon them.
2 1 . What is true for the free-living forms is true for the
parasites they harbor.
Food ohalns and parasitic life
cycles are olosely intertwined.
14.

PRINCIPLE III
The world of nature is in a state of continual change.
Organisms comprising a given community are continually
altering the soil and water conditions of the habitat so
that those organisms originally inhabiting the area must
adapt themselves to the changes, migrate, or perish. Thus
one community paves the way along the environmental path
for another community in a dynamic progression called
ecological succession.
1.
2.
5.
4.

The tendency to change is characteristic of life, whether
at the cellular, individual organism, population or com­
munity level.
The changes which take place at the community level tend
to put the pbant life in better adjustment with the soil,
water, light and biological conditions in the area.
Once the adjustment (between the plant life and other
conditions in the area) is affected, a relatively stable
condition known as the climax stage is reached.
The series of changes leading to the climax stage is called
ecological succession.

395
5.

The primary causes of ecological succession are (1) the
reactions upon the habitat by the o r g a n i s e living there,
and (2 ) modifications of the habitat by such physical forces
as silting, chemical changes in the soil -caused by leaching
of salts from the soil, drainage of swamps, fire, cultivation
and many others*
6 . (In all instanoes) the biological and physical forces at
work oause a change in the plant life of the sre g , and changes
in the. plant life oause ohanges in the nature of the animal
life.
In this way the character of the community changes
and one type of community paves the way along the environ­
mental path for eaoh succeeding community until the relative­
ly stable olimax community is reached.
?. A typical exanple of the interaction (leading to the olimax
community) is the transition of a given area from barren
rook to the olimax vegetation of the area.
8 . The first organisms to Invade a barren rock substrate are
terrestrial algae, bacteria, lichens and mosses.
9.
Through the continued action of climatic forces together
with the biological action of terrestrial algae, bacteria,
lichens and mosses, soil is formed from barren rock sub­
strate.
10. When soil is formed in an area the environment is prepared
for an invasion by Various herbs and weeds.
11. Herbs and weeds are characterized by possessing light seeds
whloh can very easily be transported by the wind.
1 2 . Eventually, when sufficiently deep soil has been formed,
shrube and trees may Invade the area, leading to dominant
forms of vegetation which make it difficult for new species
to gain a foothold.
15. Frequently the climax type of vegetation for a given area
is not reached because it Is arrested at eome stage in the
succession by suoh human activities as repeated burning or
the constant use of an area for grazing purposes.
14. Arrested development (toward the climax stage) is temporary,
however, for once the human Influence is withdrawn, the
natural prooess of change continues toward the climax type
of vegetation.
15. Eoologloal succession may also have its beginning in a lake,
pond or stream Instead of barren rock.
18. When ecdlogioal suooeflsion begins in a lake, pond or stream
the invasion of shore plants and the gradual deposition of silt
. rsduoe the area of open water and eventually a bog or vswamp
results.
17. The drying up of a bog or swamp and subsequent changes in the
soil conditions create an environment suitable for land plants.
18. Over a period of time (beginning with a lake, pond or stream)
a olimax community with its characteristic animal life will
t develop.

396
19.
20.
21.

22.
23.

24.

Succession also occurs within a community.
An example of succession within a community 1:: the- rjuccesslon
In a culture Jar of protozoa,
In a new culture of protozoa the clear culture medium be­
comes cloudy because of the rapid accumulation of bacteria.
Changing environmental conditions in the culture Jar then
permit the development of various types of pirotosoa, even­
tually leading to a culture of the bell-shaped, italked
protozoa called Vortloella.
In the type of succession occurlng within a culture of
protozoa, the accumulation of metabolic wastes together
with the exhaustion of food are important determining factors
A knowledge of the natural trends in ecological succession
is of Importance to man in his efforts to conserve soil, im­
prove grazing conditions for his cattle, Increase the pro­
ductivity of his forest lands, and conserve his wildlife.
Human efforts to conserve the .replaceable natural resour­
ces without consideration of the natural trends in ecological
succession are doomed to failure.

PRINCIPLE IV
The oarbon cycle and the more complicated nitrogen cycle
exemplify the complexity of the Interrelationships among
living things and their physical environment.
In each
instance there is a cyclic chain of events from the in­
organic to the organic and back to the inorganic elements
of the environment.
1.

The physical environment of animals and plants o'onslata
of three media - soil, atmosphere and water.
2.
Operating within these media (soil, atmosphere, water) are
the physical factors of light, heat, pressure, gravity and
chemical concentrations.
3.
Soil is essential to life because it is the source of the
chemical elements and compounds necessary for the formation
and maintenance of protoplasm.
4.
Living matter contains a minimum of ten essential elements.
6.
The essential elements (in protoplasm) are oarbon, hydrogen,
oxygen, phosphorus, potassium, iodine, nitrogen, sulfur,
oaloium, lrbn and magnesium.
6.
The essential elements oan be remembered easily by using
the memory devioe "C. Hopkins Cafe, mighty good".
?•
Sodium and chlorine are essential to animal nutrition al­
though not indispensible to plants.
6.
Soil is a mixture of fragmented rooks and minerals, organic
matter, water and air in varying proportions.
9,
Soil develops under the influence of climate and living
organisms.
1 0 . The original rock of the earth is broken up in weathering
by the action of the wind, rain, heat and freezing.

11.
12.
13.
14.
15.
16.
17.
16.
19.
20.
21.
22 .
23.
24.

25.

26.
27i
28.
29.
30.
31.

The extent of weathering in any area depends upon the ollmate.
Dead organisms contribute the organic matter of their bodies
when they deoompose.
Living organisms also contribute organic matter (to the soil)
In the form of waste products.
Some living organisms, such as earthworms with live in the
soil, improve It by burrowing through It, feeding on it, and
mixing the organio matter and minerals.
Tons of soil per aore are moved and enriched each year by
earthworms•
The production of good soil requires long periods of time,
It Is estimated that 300 to 1000 years are required to produoe one Inch of productive soil by natural processes.
Because it requires such long periods of time to produce
soil the Importance of soil conservation becomes obvious.
The chemical, physical, and biological faotors operating
within the soil exert their primary effects on the root
systems of plants.
The texture of soil, its temperature, and its water, air
and mineral oontent must be optimum if plants are to attain
their maximum growth and vigor.
The oxygen oontent of air In the soil is especially sig­
nificant because of its; influence on the respiratory activity
of plant roots.
Water-logged soil will eventurlly oause the death of plants
because water fills the a i r spaces in the soil, thus depriv­
ing the plant of Its oxygen supply*
Deficiencies in concentration of certain mineral salts In
the soil reduce the vigor of plants.
The laok or insufficient abundance of any one of them
(certain mineral substances) can limit the growth and de­
velopment of the plant.
A biological principle based upon (one phase) of the re­
lationship of organisms to environmental faotors is oalled
the il’Law of the Minimum".
It states that the factor present
in minimum concentration in the envoronment of an organism
may limit the growth and distribution of that organism.
An example of the "Law of the Minimum" Is that there may
be a superabundance of water and optimum conditions of
light and dissolved mineral salts, but the photosynthetic
activity of any given plant may fall below the energy re-i
quirements of the plant if the concentration of carbon
dioxide is too low.
Should this persist over a period of
time the plant will die.
The atmosphere is (one of) the basic media in which organ­
isms live and from whloh they obtain their requirements.
The atmosphere is a gaseous envelop that surrounds the earth.
The atmosphere oonslst mainly of nitrogen, oxygen and
oar&on dioxide.
Nitrogen makes up 79 peroent of the atmosphere by volume
and is an essential element in living organisms.
The amino acids cannot be synthesized without nitrogen.
Proteins cannot be make without amino a d d s .

32.

Because amino acids cannot be synthesized without nitrogen
and proteins cannot be nmde without amino acids, the life
organisms Is dependent on the nitrogen of the atmos­
phere,
33. Despite the abundance of nitrogen in the air, green plants
which manufacture the amino acids cannot obtain the nitrogen
directly from this overhead supply,
34.
Greeo plants must get nitrogen from the nitrogen compounds
in the soil In the form of soluble salts and ammonia.
35. Nitrogen Is constantly being lost from the soil to the atmos­
phere and ie being constantly returned from the atmosphere
to the soil.
36.
The Interchange of nitrogen between the atmosphere and the
soil is cyclic in nature.
37.
The cyclic interchange of nitrogen between the atmosphere
and the soil is one of the most fendamental interrelationships
between living matter and the inanimate environment.
38.
Certain bacteria known as nitrogen-fixing bacteria can utilize
atmospheric nitrogen to manufacture nitrates (NOg),
39. Nitrogen-fixing bacteria may be living either in the nodules
of the roots of leguminous plants, such as peas, clover,
alfalfa and beans, or as free organisms in the soil,
40. The nitrates produced by nitrogen-fixing bacteria are used
by plants in the synthesis of amino acids and plant proteins,
41. Animals eat (the) plants or saprophytic plants attack them
and digest the proteins to amino acids,which are then resynthesized into the proteins of the devouring organisms.
42. In animals some proteins are used to produce carbohydrates,
with the result that nitrogen is released and excreted as
urea.
43. Urea and eventually the dead animal body are decomposed
by putrefactive bacteria which change the nitrogen compounds
to ammonia (NH3 )•
44.
Ammonia is returned to the soil (through the action of
putrefactive baoterla) and is acted upon by a group of
bacteria which change ammonia into nitrites (NOg).
45.. A third group of bacteria, the nitrate bacteria, change
the nitrites into nitrates (NO*).
46. Basically there are four processes Involved in the nitrogen
cycle: (1 ) the process of decomposition involving the organ­
isms of decay, (2 ) the process of nitrification in which
ammonium compounds are changed into nitrite and nitrate
oompounds, (3 ) the process of denitrification in which
certain kinds of bacteria operating under certain soil con­
ditions change nitrogen compounds of thf? soil into free
atmospheric nitrogen, and (4) the nitrogen-fixing process
involving the nitrogen-fixlng bacteria which either live in
a symbiotic relationship with leguminous plants or are freeliving and convert atmospheric nitrogen into the usable
nitrate form.
47.
The element corbon is also constantly; being withdrawn from
the environment to become a part of the organic makeup of
living things,
*

.

The source of the carbon used by living things le the
carbon dioxide of the atmosphere and waterf
49.
The atmospheric supply of carobn dioxide is replenished
through the respiratory activities of animals and plants,
especially bacteria; through the combustion of animal and
plant residues such as wood, coal, petroleum, gas and the
dead remains of organisms; and through volcanlo eruption
which bring into the atmosphere carbon dioxide trapped in
the earth's crust in the geologic past.
50.
Carbon dioxide diffuses into, green plants and is used in
the manufacture of simple sugars.
51.
The simple sugars (manufactured by the plant) may be
oxidized immediately by the plant for energy, in whloh
oaae the oarbon dioxide is released again to the atmos­
phere, or used again in photosynthesis.
52.
The simple sugars (manufactured by the plant) may beoome
a part of complex carbohydrate moleoules to be used as a
art of the plant struoture.
he simple sugars (manufactured by the plant) may be sjmthesized into proteins or fats.
54.
If the oarfeon becomes a part of the plant as complex carbo­
hydrate, protein or fat, it remains in the plant until it
is digested and used by the plant or until the plant is
eaten by an animal or dies.
55.
If the plant is ooneumed by an anlma:., it is digested and
the oarbon may beoome a part of the animal body as animal
carbohydrate, fat or protein, or it may be used for energy
and oarbon dioxide may be given off as a by-produot.
56.
If the plant dies, bacteria and other organisms digest and
deoompose the plant compounds and eventually release the
carbon as oarbon dioxide.
57.
The oarbon in animals is also released to the atmosphere
as oarbon dioxide when the animal dies and decomposes.
58. Decomposition of organic compounds by bacteria and other
fungi is known as either fermentation, putrefaction or
decay.
59. By one of the three processes, fermentation, putrefaotlon,
or decay, the oarbon becomes a part of the microorganisms
before iv is released to the atmosphere as carbon dioxide.
60. Fermentation is the breakdown of sugars by bactdrla and
yeast with the production of alcohols and acids.
61. The souring of milk is an example of fermentation. Milk
oontalns sugars which are changed through bacterial action
to lactic acid.
62. The sour taste of dill pickles is also the result of fer­
mentation.
65. Certain of the products of fermentation are carbon dioxide
and water.
64. Putrefaction refers to the decomposition of protein moleoules
by microorganisms.
66 . Protein moleoules (may be broken down by microorganisms)
into simpler compounds to produce amino acids and finally
oarbon dioxide, ammonia, hydrogen sulfide, nitrates,and
other simple compounds.
48

?

ij.00
66.

67.

66.
69.
70.
71.
72.
73.
74.
75.
76.
77.
78.
79.
60.
81.
82.
83.
84.
85.

86

.

87.

88

.

89.

Soros or the intermediate products of p u t r e faction have
unpleasant odors.
The mloroorganisms that oause putrefaction are anaerobes.
Anaerobes do not require free oxygen for respiration, but
obtain their oxygen from the compounds they decompose.
Decay Is similar to putrefaction in that protein compounds '
are decomposed.
Decay differs from putrefaction In that no unpleasant odors
are produced.
The process of decay Is carried on by aeroblo microorganisms
that must have free atmospheric oxygen for respiration.
Oxygen, like nitrogen and oarb0n, la constantly being passed
back and forth between organisms and the atmosphere.
Both plants and animals remove oxygen from the atmosphere
and use It In respiration.
The green plants return oxygen to the atmosphere through
the photosynthetic process.
Though oxygen Is almost universally available, it is muoh
more abundant In the atmosphere than In water.
Many fresh water lakes are deficient In oxygen at the lower
levels during the summer months.
Pollution frequently causes a depletion of dissolved oxygen
In lakes and streams.
Atmospherlo oxygen decreases In concentration with Increase
In altitude.
Breathing air at high altitudes results In oxygen starvation
or anoxia.
Whether in a pond or at altitude, low oxygen concentrations
are frequently a limiting factor to the life activities of
organisms.
Water covers about 72 percent of the earth's surface.
If the water on the earth's surface were uniformly distri­
buted It would form an ocean approximately two miles deep
over the entire faoe of the earth.
Water evaporates from oceans, lakes and streams, land sur­
faces and living things and Is transferred as water vapor
to all parts of the world.
The water vapor In the atmosphere ultimately precipitates
as rain, fog, dew, enow, or hall and provides regions far
removed from the ooeans with water.
The cycle of water from earth's surface to atmosphere and
back Is called the hydrologic cycled
The hydrologic cycle has undoubtedly oontlnued with little
change throughout the geologic past until the present time.
It Is estimated that about 6*500 cubic miles of water run
off the land annually by way of streams.
Annually, the run off water carries with it some five
..
trillion tons of dissolved and suspended matter, all derived
from the soil and the earth's crust.
The Increasing saltiness of the sea is an evldenoe of the
effectiveness of the erosion process.

t o

90o
91.

92.
93.
94.
95.
96.
97.
98.
99.
100.
101.
102.
103.

104.
103.
106.
107.
108.
109.
110.
111.

M a n *8 present and future welfare demands an effective conr
trol of the destructive action of water.
As a basic environmental medium, water has many outstand­
ing characteristics.
It serves aa a solvent, food, cir­
culating medium, temperature regulator, and catalytic, hydro­
lytic, and Ionizing agent.
Water Is an essential constituent of protoplasm and con­
stitutes between 40 and 90 peroent of its substance.
Unless animals and plants oan adapt themselves to the water
conditions of their surroundings, they must either migrate
to more congenial conditions or perish.
The water oontent of an organism frequently determines Its
ability to withstand unfavorable environmental conditions.
An organism's water requirements are often partially met
by the organism's ability to extract a supply of water
through the metabolism of organlo foods.
In most instances (however) living things depend upon free
water to supply their needs.
The aotivatlon of the elements borrowed from the earth's
crust and atmosphere and organized Into living things Is
affected by the energy from the sun.
Organisms derive their energy from their surroundings and
also give It up to their surroundings.
The available radiant energy Varies greatly on different
parts of the earth and also exhibits annual and dally cyollo
fluctuations.
Solar radiation penetrates the earth's atmosphere quite
readily, but water absorbs certain of the wave lengths.
These facts (concerning energy) are of significance with
relation to the distribution and activities of animals
and plants.
Light is essential to the prooese of photosynthesis and
consequently Is basic to the food supply of all living
things.
The photosynthetic process carried on.by chlorophyll,
bearing plants transforms the radiant energy of the sun
Into chemical energy, thus bridging the energy gap be­
tween the physical and blologloal worlds.
A s an environmental fqotor, light must be considered In
terms of Its quality and Intensity.
The quality of light refers to its wave length.
Color of light Is a function of Its wave length.
Light Intensity refers to the quantitative aapeots of light.
The environmental effeote of light quality and light In­
tensity are well exemplified by the requirements of the
photosynthetic prooess.
Chlorophyll Is most rapidly decomposed in the orange-red
region of the vlsable speotrum.
It „ls also true that more light Is absorbed by ohlorophyll
in the orange-red region of the vlsable spectrum than In
any other.
,
.
The optimum quality of light for photosynthesis (consequently)
Is light of the orange-red color.

1402
112.
113.
114.

115.
116.

If the light intensity is too great, light, of these wave
lengths (orange-red> becomes a limiting factor in photo­
synthesis.
Plants need a definite number of energy units of light
for their growth and maturation*
Generally, a plant funotions more efficiently when the
light is distributed over a longer period of time at a
lower intensity than when the opposite conditions pre­
vail.
Animals, a l m o s t w i t h o u t exception,
of light.

can live Independently

Some animals such as the cave dwellers, deep-sea fishes,
and intestinal parasites normally live in environments
lacking light.
117.
Light does influence the activities and behavior of the
majority of animals.
118.
The colors of many animals change in response to the in­
cident of light.
119.
The color changes in animals in response to the incident
of light are responses of the pigment-containing cells
in the a n i m a l ’s integument and are often adaptive in
nature.
120. In some fishes, as in some birds and mammals, the sexual
cycle appears to be determined largely by the intensity
of light.
121. The behavior responses of animals and plants to light are
called phototroplsms.
122. Earthworms generally move away from the source of light.
123. Moths and many other insects move toward a given light
source.
124.
Plant stems are definitely positive in their reaction to
light.
12b. Plant roots are negatively phototropic.
126. One of the most spectabular responses to light made by
any living organism is the phototropic response of a fun­
gus which lives in cow or horse dung and which can shoot
its spores toward a spot of light with remarkable accuracy.
127.
Animals and plants can live, within only a relatively nar­
row range of temperature.
128. Animals and plants are extremely sensitive to sudden
changes in temperature and are frequently killed at tem­
peratures only a few degrees above those at which they
are accustomed to live.
129. The death of organisms because of heat is best explained
at present by the fact that the proteins of the living
oells beoome coagulated in the same way that egg albumin
coagulates when heated.
130. The water content of organisms seems to b e an important
faotor (in resistance to heat), susceptibility to hefct
increases as water oontent increases.
131. Animals and plants also may be killed by cold.

132,
133,
134,
136.

Water oontent le an Important factor (in resistance to
cold)
susceptibility to cold increases as water oontent
lnoreases,
It is generally agreed that the formation of ice crystals
in the tissues causes death,
The rate St whloh blologloal reaotions ooour depends wary
definitely upon the surrounding temperature.
Aooordlng to a physloal law, the velocity of chemical re­
actions lnoreases two or three times with each rise of
10 C. in temperature. Metabolic processes conform to this

law in a general way .
136.
137.
138.

139.
140.
141.

142.
143.
144.
146.
146.
147.

148.

(A more exact generalisation is that) metabollo reaotions
are controlled by the slowest reaction in a metabollo
system and that these systems have oritleal temperatures.
*nsymes are active within a marrow temperature range,
Cold blooded animals do not have temperature-regulator
meohanlsms and consequently their metabollo prooesses are
more subject to temperature fluctuations than those of
warm blooded animals.
Temperature affects the distribution of plants and animals

on the earth.
Temperature influences the mechanical and chemical changes
whloh ooour in soil and thus it Influences the nature of
the plant o over of the region.
The distribution of herbivorous animals is correlated with
the distribution of plants and the distribution of oarnlvorous and omnivorous animals is associated with the
distribution of their prey.
A n living things are subjeot to mechanical pressure in
the environment.
Aquatio forms must withstand the pressure of the water
whloh lies above them.
Terrestrial forms are adapted to the atmospherlo pressure.
In water, a change in depth of 34 feet is equivalent to
a change in preseureof one atmosphere (14.7 pounds per
square inch).
On land, the atmospherlo pressure deoreases with an in­
crease in altitude.
At an altitude of 2000 feet above sea level, the atmos­
pheric pressure is a little less than one atmosphere,
and at 18,000 feet approelmately one-halt of one atmos­
phere.
Wien Stephens and Anderson made their stratospherio bal­
loon flight to an tfftltude of 72,696 feet in 1936 the atr
mospherlo pressure on the outside of their pressurised
gondola was approximately four-hundresthe of one atmos-

here.

t 63,000 feet the atmospherlo pressure is so low
S
human blood would begin to boil spontaneously.
160..
161.

that

The oaqrgen pressure at Altitude deoreases proportionately
to the decrease in total atmospherlo pressure.
Deep sea fishes live normally under pressures exoeedlng
eight hundred atmospheres.
Man requires the environment
within a bathoephere in order to study deep sea forms at
relatively moderate depths.

152.'
!

155.
154.
155.
156.

157.
158.
159.
160.
161.
162.
165.
164.
165.
166.
167.
168*
169.

The hydrostatic pressure noting upon deep-sea fishes Is
so great that when suoh forms are brought to the surface
the air In their swim bladders expands to ouch an extent
that It Is everted from the body a n d the fish Is said to
explode.
®lvers working In oalssons under pressures exceeding one
atmosphere must return to the surface slowly so that their
bodies oan beeone adapted to the decreasing pressure.
Unless (divers working under pressure in caissons return
to the surface slowly) a condition known as "dasslons
disease" oan develop and may prove to be fatal,
Aviators flying at high altitudes often complain of the
"bends" and surfer symptons similar to caisson disease.
The symptons iot caisson disease and bends) are oaused
by the release of nitrogen In the form of bubbles from
the body tissues due to the deoreased atmospherlo pressure.
As In the oase of other physical faotors of the environ­
ment* living things in general are adapted to a relatively
narrow range of pressures.
All living things respond to the foroe of gravity*.
(Gravity) Influences the struotural oharacteristics of
organisms as well as their behavior and physiological
adjustment to the environment.
A notable example of the way In w h l o h the factor of gra­
vity affeots animal structure Is the femur of higher ani­
mals*
The engineering design of the human femur admirably adapts
this part of the skeleton to meet the stresses produced
by the. Jforoe of gravity.
A nother example of the Influence of this factor Is evi­
dent in the adaptations whloh aocur in the skeleton of
birds.
(In birds) reduetlon In weight without loss of strength
results in an Increase:in the power of flight*
As far as terrestrial forms are concerned* the factor of
gravity definitely limits the maximum else that an animal
oan attain*
The behavoral and physiological adjustments of organisms
to the factor of gravity are quite evident in living things,
Acting in conjunction with plant hormones* the factor of
gravity oauses the roots of plants to grow downward and
the stems of plants to grow upward*
Suoh responses (as those shown by roots and stems) result­
ing In movements of organisms are oalled troplsms.
In animals specialized organs are often present whloh
keep the animal, aware of Its position in relation the earth*
These specialized organs are oalled statocyst*
The semicircular canals of the human ear represent the
highest degree of development of the type of organs whloh
keep animals aware of their position In relation to the
earth.

170.

171.
172.
173.

174.
175.
176.
177.
178.
179.
180.
181.

182.
183.

184.
185.
186.
187.
188.

It has been aiggeeted that the movementa of one-oelled
animals and many movements of plants are responses to
stumuli set up by staroh grains or other inclusions in
cells as these granules fall through the viscous proto­
plasm attracted by the foroe of gravity.
In suoh instan­
ces the oell note like a etatooyst.
Organisms must be able to adjust themselves to their ohemlo41 environment.
The ohemloal environment, supplies the Organism or tissue
with essential ohemloal foode.
The ohemloal environment produces conditions of osmotio
pressure and aoldlty or alkalinity (hydrogen-ion con­
centration) whloh must be optimum if the living matter
is to function normally or at all.
Red blood oorpusolea of a frog, when placed in mammalian
physlologloal salt solution, will loose water and shrink.
Plants, If overfertillzed, will die as a consequence of
of the failure of their roots to adjust to the increased
salt concentration of the soil water adjacent to the plant.
The adaptations of organisms and tissues to chemicals oan
also be extremely speolflo.
Potassium ions have a definite lnfluenoe on the heart beat
of animals.
Magnesium is absolutely lndlspenslble to the formation of
the chlorophyll raoleoule.
The degree of aoldlty or alkalinity of the chemical environ­
ment is of great importance.
Adjustment of the hydrogen-ion oonoentration beyond an
optimum range is a common method of inhibiting bacterial
rowth.
n human reproduction the degree of aoldlty of the female
reproductive tract is a common oause of sterility because
the male reproductive elements are adapted to a relatively
marrow range of hydrogen-ion oonoentration, and if the
female traot is too aoid the spermatozoa are killed.
When living tissues or organisms cannot adjust themsslves
to their ohemloal environment they die.
This is the basis
of chemotherapy in the field of mSdloal science.
Antibiotic suostanoes suoh as penlolllln or streptomycin
create an unfavorable ohemloal environment for certain
types of bacteria and inhibit the growth of the bacteria,
thus enabling protective meohanlsms of the body to exert
their lnfluenoe.
Metalllo compounds suoh as meourio chloride and iodine
oause the death of the bacteria in a short time.
If the ohemloal oonoent rat ions are not too unfavorable,
organisms oan adapt themselves to changes in their oheml­
oal environment.
Plants of the desert or seashore adapt themselves to in­
creasing concentrations of salts in their environment.
Bacteria oan adapt themselves to sulfonamide concentrations
to the extent that they beoome resistant to the ohemloal.
Himuin beings living at high altitudes, suoh as the plateaus
of Tibet and Peru, are adapted to the low oxygen concen­
trations prevailing at those altitudes.

f

U06
189.

The adjustment of living things to their chemical environ­
ment Illustrates strikingly that adaptability is a funda­
mental characteristic of living matter

PRINCIPLE V
Soolal groupings among individuals of the same species
and associations between individuals of different species
are adaptive responses which often increase the chances of
survival for the organisms involved.
1.

In general animals live together.
Birds form flocks while
fishes form schools.
Mosquitoes swarm and wolves travel in
acks and hunt the herds of deer.
Bees, wasps and ants
uild their own homes, where eaoh individual has a speoiflo
function to perform.
Associations of animals vary in their degree of organisa­
tion.
Some associations of animals are completely lacking in any
degree of integration and, in fact, are associated only
through the chance operation of natural laws.
An example of accidental association is organisms cast into
long drift lines along the sandy beaches of lakes.
In suoh
drift lines one oan find many organisms including lnseots,
small bivalves, aquatic snails, and even fish.
Associations of animals may be brought about because the
animals all react the same way to the same kinds of environ­
mental stimuli.
The collection of insects about a light on a summer evening
is an example of animals reacting in the same way to the
same kind of environmental stimulus.
Associations or aggregations of animals are oaused by
forces or factors that are more social in nature.
Suoh aggregations as bird flooks, schools of fish, "dancing
midges"7 and herds of deer are oaused by reactions to each
other.
Instead of responding to an Impersonal external force
(animals which associate beoause of reaotions to each other)
collect as a result of positive reaction to the presenoe of
others like themselves.
One aspect of aggregations (with a social basis) may be
sexual a nd result in the collecting together of two or
more individuals during the breeding season.
Sex. however, is not the only faotor (Involved In aggre­
gations of a social nature) because many animals collect
together in nonbreeding seasons or continue their associa­
tion long after reproduction is accomplished.
In some(animal) forms the association is distinctly a social
phenomenon carried to a high degree of specialization.
For example, (of an association which is distinctly a social
phenomenon carried to a high degree of specialization) hives
of bees with the reproductive queen, the males or drones and
the sterile fenutles or workers constitute a permanent associa­
tion that is organized so that the group Is an entity in .
itself. .Certain individuals may die but the group persist.

S

2.
3.
4.

5.
6.
7.
8.
9.

10.
11.

12.
13.

U07
14.
15.

16.
17.
18.
19.

.

20
21

.

.

22

26.

24.
25.
26.
27.

28.
29.
60.

Anta a n d t termites alao represent 3oeIftl organisation in
a complex form.
Human beings live together in an intricate and complex
Interdependence.
The human from birth to dsath la a part
of a group.
His distinctly human characteristics are the
result of group living, and the group goea on after the
individual is dead.
Group or social living is a common blologloal phenomenon.
Group or sooial living varies from loose, temporary, and
aooldental associations to highly integrated and permanent
interrelationships.
(Apparently), living together offers some advantages over
the condition of living alone.
The advantages of cooperative group effort in human society
are obvious.
Many examples are available demonstrating that the com­
bined, cooperative action of many people can accomplish
task that are impossible for a single individual.
The advantage gained by the less organized and unconscious
associations (such as fish in a sohool or birds in a flook)
is survival.
A n example that illustrates the survival value of aggrega­
tions of animals is as follows: A large group of fish oan
tolerate an amount of poison in the water that would kill a
▼ery few.
The reason is that eaoh one of the group absorbs
a small protlon of the poison and reduces the total amount
so that on one fish is seriously affeoted.
If only a few
fish were present, the amount absorbed by each one would be
enough to kill it.
Another example of survival value of aggregations is the
collection of certain birds in close groups during oold
weather.
Colleotlvely they can withstand the low tempera­
ture, while individually they would perish.
Sooial groups have certain characteristics in common.
The characteristics which sooial groups have in common are
sooial characteristics and are derived from the interaction
between the members of the group.
The sooial characteristics that groups have in common invaiVe (l) the holding of territory, (2) domination-subord­
ination, and (6 ) leaderehip-followshlp.
The different types of interactions in the group may oocur
in fairly pure form, or they may grade into each other, even
in sohools of fish, to give oomplloated organizational
pattern
The oonoept of territory refers to an animal's recognition
and proprietorship of a certain area.
It Includes homing
or the defense of a certain area, or both.
Homing reaotlons oocur when an animal returns to a speelfio
area after it has left it.
The (return) distance covered (in the homing reaction) may
be only a few feet as in certain mollusks, or it may be
hundreds of miles, as in homing pigeon^ and the golden plo­
ver.

U08
31.
32.
33.

34.
35.
36.
37.

36,

39,
40,
41,

The defense of a given area Is characteristic of territorial­
ity*
Birds defend their selected territory against Invaders, as
do many fishes, lizards and mammals. Including man,
Organisms that 'show a reaction to territory react negatively
to invaders of the same species.
They prevent, toy actual
oomtoat, or threat of combat, any individual of the same
hind from entering the selected area.
An exception to this(defense of territory against entrance
toy organisms of the same kind) Is made to a mate or mates,
Organisms (that show territoriality characteristics) react
positively to the (selected) territory, seeking it and liv­
ing in it.
Sooial hierarchies develop in groups of animals based on the
second characteristic of group living, dominance-subordlnatlon,
An example of dominance-subordination is the peck order in
chickens.
A newly collected flock of chickens will, in a
relatively short space of time, develop a sooial organization
based on the domination of certain individuals over others.
The sooial order is established and maintained by the giving
and receiving of pecks, or by reactions to threats of peck­
ing.
From this the term peck order has come to refer to
established sooial hierarchy in chickens.
When two chickens meet for the first time either there is
a fight or one gives way without fighting.
The successful
bird in the initial encounter retains the right to peck
the other bird at any subsequent encounter.
*hls process
oontinues throughout the flock, each chicken engaging in
battle or threat of battle until all fall into a serial
hierarchy with one having the right to peck all other chick­
ens and not be pecked in return; with a second being pecked
only by number one while it pecks all other hens in the
flock; with a third submitting to numbers one and two but
dominating all the remaining birds, and so on. down to the
last bird in the flock which receives the pecks of all and
gives ndne in return.
Other animals that show a domination-subordination type of
sooial organization include fishes, lizards and mammals,
Certain human sooial organizations are suspiciously similar
to peok order.
W. C, Allee has summarized the qualities that make for high
social status in groups of vertebrates as follows: (1 ) the
stronger individual usually wins in pair oontaots, (2 ) ma­
ture animals usually dominate those less mature, (3) larger
animals usually have a higher social rank than their smaller
associates, (4) the location of the first meeting is oftea i
important, sinoe many animals fight best in or near their
home territory, (5 ) an animal surrounded by members of its
own group often wins over a stranger, (6 ) animals with young
tend to fight more fiercely than at other times, (7) males
usually dominate females, (8 ) the amount of male hormone
present often determines the sooial dominance of either sex,
(9 ) the female consort of a dominant male tends to be ac­
corded his sooial status so long as she remains near him.

#
42.
45.
44.
45.

46.
47.
48.
49.
50.
51.
52.
55,
54.
55.
56.
57.
58.
59.

I4.09

Hereditary differences are important In relation to domlnatIon-subordination.
Inbred strains of nice tend to differ both In aggreslveness
and in fighting ability.
Defeat which results in lowered sooial status is often
accompanied by easily recognized changes in behavior.
A defeated fish may drop its challenging posture of tense
body and ereot fins; the fish seems to hang limply in the
water; it backs away slowly and then turns and flees. Many
animals, among them hens, mice and boys, not Infrequently
emit characteristic cries when beaten.
The head furnishings
of defeated hens sometimes blanch, while those of the Victor
remain flushed.
Defeated mice rear up in characteristic
postures.
Other signs of low sooial rank Include the avoid­
ance of encounters wltheuperiore; defeated hens move about
quietly, often with head held low, or hide in out-of-the-way
places or in protected lilohes.
Leadership, another characteristic arising out of group liv­
ing, consists in giving guidance and directing others along
a certain course or pattern of behavior.
A leader may be able to attract others to follow him, but
sometimes force is neoessary to control the followers or
even to secure them.
The position of leadership is held by the animal that Initi­
ates, stabilizes, or Integrates behavior of the group.
Leadership may be held by either male or female, who may be
young, mature or old.
Leadership may be held by one individual or a group of lndir
vlduals.
The leader may lead in the physical sense of going before
when the group ohanges its location or activity.
However,
this is not always true.
The animal moving in advance may not be the real originator
of the movement.
In some flocks of birds the bird in advance in flight is
simply following al&ng in front of the flock. Any ohange in
direction originates within the £ody of the flock.
Leadership may or may not be associated with social statue.
In flooks of. hens leadership often rest in the mid-sooial
ranks rather than with the number-one hen in the peck order.
In ants lndivldual-to-indlvldual dominance is unknown, pet
leadership exist.
Among groups of mammals the soolally dominant animal is
often the leader.
Among the red deer of Sootland the males exert dominance,
but the real leadership is held by a female.
In rhesus monkeys there le a complete linkage of domlnanoe
and leadership.
The strongly dominant and aggressive in­
dividual is also the leader.

60.

In a community relationships exist between species whioh
result in (1 / the toleration of one species by the other.
(2) the exploitation of one speoies by the other, and (3)
the unoonscious cooperation of two species which results
in mutual benefit being derived from the association*
61.
The term symbiosis is used by the biologist to include all
_
(®noh) partnerships (which exist in a community).
62. The toleration of one speoies by another is called commensallsm.
63.
The exploitation of one species by another is called para­
sitism.
64.
The unconscious cooperation between speoies is called mu­
tualism.
65. Among the most interesting of the commensal relationships
are those involving species of insects and flowering plants.
66. The collection of neotar and pollen by honey bees to supply
food for the bee oolony is a n example of a commensal re­
lationship.
In the pursuit of nectar and pollen the honey
bees make possible oross-fertillzatlon in the plants.
67. The commensal relationship may be casual, (as in the oase
of the honey bee and the flowering plant) or it may be ob*»
llgatory as in the oase of the Yuooa moth and the Yucca
plant,
68 . The only lnseot oapable of pollinating the Yucca flower is
the Yuooa moth.
69. The female moth, after collecting pollen from several sta­
mens, drills a hole through the ovary wall of the YuocS
flower and lays her eggs among the ovules of the flower.
Development of the ovules into seeds is Insured by in­
serting the pollen grains into the oanal of the pistil.
70. Only a few eggs are laid in any one flower thus insuring an
adequate food supply for the larvae without endangering
the propagation of the plant upon whose existence the sur­
vival of the Yuooa moths depends.
71. Mutualism is found between species of animals, species of
lants or between animals and plants,
mutually beneficial relationship existing between an
animal and a plant is seen in the relationship between the
een alga Chlorella and the fresh-water coelenterate hydra,
e green alga lives within the body walls of the hydra and
utilises the oarbon dioxide released by the animal to manu­
facture sugar by photosynthesis.
The hydra, on the other
band, uses the oxygen liberated in photosynthesis in its own
respiratory activity.
74.
Other examples of mutually beneficial relationships are those
existing between oertaln fungi and algae resulting in the
oomposite plants called lichens; the relationship between the
root-inhabiting nitrogen-fixing bacteria and leguminous
plants; and the relationship between certain termites and
their intestinal protosoa.
75.
Termites cannot live without the presence of the protozoa
(in.their digestive tract) for the protozoa digest the wood
(cellulose) eaten by the termites.

S

S

76.
77.
78.
79.
80.
81.
82.

88.

84.
86.
86.
87.
88 .
89.
90.
91.
92.
93.
94.
96.
96.

Parasites are organisms, either plant or animal, that live
on or within another organism and at the expense of the
other organism,
The benefits derived by the parasite may include food, shelter, dispersal, and a means of completing the life history.
The host is an organism that harbors a parasite.
If the parasite is in an immature stage of growth, the host
is usually known as an intermediate host.
If the parasite is adult, the host that harbors it is known
as the final host.

The habitat of the parasite is the host.
The habitat provided by the host is oomprable to the water
and land habitats of free-living forms, and parasites beoome adapted to it Just as free-living organisms become
adapted to their (habitats).
The pafasltlo habitat is essentially of two types.
One is
eotoparasltlo, in whloh the parasite lives on the outside of
the host.
The seoond is endoparasitlo, in which the parasite
lives within the host.
Examples of edtoparasltlo organisms are lice, fleas, and ticks
on man.
Examples of endoparasitlo organisms are protoeoan blood para­
sites that oauae malaria, tapeworms that live in the lntestlme, and baoterla that live in the respiratory tract.
Most parasites can live only in a specific host or hosts.
Parasites beoome adjusted to a oertaln host environment and
oan tolerate no" other.
This condition is known as host
speolflolty.
(Furthurmore) parasites usually are restricted to living
in or on only certain parts of the host.
This is tissue
speolflolty.
Tissue speolflolty is exemplified by the viruses whloh
cause rabies and poliomyelitis and affect the nervous sys­
tem only.
Other viruses, such as those that cause ohiokenpox and small­
pox, attack the skin.
The parasite is not the only part of the host-paraslte relat­
ionship that shows speeiflolty.
The host also is speolflo in its tolerance of parasites.
It
accepts some and rejects others.
A host that tolerates the presence of a parasite is said to
toe susoeptltole.
A host that does not tolerate a parasite is said to toe im­
mune.
Animals and plants that are parasitic have evolved from freeliving ancestors.
Parasitism probatoly began as a result of a chance enoounter
of two organisms in which one served as a vehiole for the
transportation of the other.
This relationship probably per­
sisted for sometime, during whloh the future parasite came to
depend upon the host for food and perhaps other necessities,
and as the degree of dependence grew the degree of parasitism
grew.

1*12

97.

98.
99.
100.
101.
102.
105.

104.

105..

106.

107.
108.
109.
110.
111.

During the evolutionary adaptation from a free-living to
a parasitic mode of life, the parasite changes, and the
degree of change usually Is correlated with the
length of time the organism has been parasitic.
Parasites that have been parasitic for a short time, In
general, show few changes and those that have been parasitic
for a long time show great changes.
The changes that a parasite undergoes are usually In the
dlreotlon of greater dependenoe upon the host.
The variations In the parasites may be simplifications of '
structure or they may be complications.
Complex life histories have developed In many parasitic
species,
Complex life histories In parasites is associated with dif­
ferences between young and adults.
When toe offspring are like the parents, as In the oase of
bacteria, both can live in the same environment and the
complex life histories do not develop.
However, when the
offspring have one form and the adults have another, they
need different environments In whloh to live and develop.
(Thus) Immature or larval parasites live In Intermediate
host, of whloh there may be one, two or three.
The adult
lives In the final host.
To complete development of the
parasite or'to complete Its life history, it must pass from
host to host,
The human pork tapeworm Is an example of a parasite having
a relatively simple life history.
The adult tapeworm lives
and reproduces within the human intestine, the fertilized
eggs pass out of the Intestine with the human excreta.
Most
of them die, but sone are eaten by pigs.
Within the pigs
they undergo oertaln growth changes and migrate until they
Invade the p l g >s muscles.
If man eats the pig's muscle
tissue In the form of insufficiently cooked pork, the young
tapeworm gains entrance Into the human digestive tract, where
It develops Into a n adult,
The total effeot of parasitism on the host depends upon a
number of factors, Including the vlrulenoy of the parasite,
the number of parasites, the resistance of the host, and
whether the parasite-host association Is temporary or per*manent and of long duration or of recent origin.
Vlrulenoe Is the oapaolty of a parasite to produce abnor­
mal conditions in a host by reproducing rapidly and. pro­
ducing highly toxic substanoea,
Parasites differ In their vlrulenoe,
Parasites that are highly virulent cause the severe diseases,
while those of less vlrulenoe cause mild Illnesses only.
The number of parasites that Invade a host has a deolded
effeot on the severity of the host's reaction.
A few parasites can usually be tolerated by the host, but
If the numbers increase the host's resistance is usually
overcome and the damage may be great.

U3
112.
lid.
114*

115.

The resistance of the host to the speolflc parasite de­
termines whether the parasite will become established.
Resistance of the host to a speolflc parasite Is great
in some oases and very little In others.
Temporary associations of parasite and host, such as mos~
qulto and man, seldom do muoh damage, while more or less
permanent associations such as tuheroulosis-oauslng bacteria,
hookworms and tapeworms can oause great damage.
When the parasite host relationship Is of long duration
and the parasite and host have lived together for countless
enerations, a mutual tolerance Bometlmes develops*
nder conditions of mutual tolerance between parasite and
host, the host may not be Injured sufficiently to oause
deatn, but he.(host) may suffer from a slight and contin­
ued Impairment of health known as a chronic disease.
If the para site-host relation Is of recent origin In the
evolutionary sense, severe reactions may oocur. The host
is unable to inhibit the notion of the parasite sufficiently
to protect Itself from harm, and as a result severe disease
and perhaps death of the host ensues.

g

117.

m
AREA 8 - INTERRELATIONSHIPS
UNIT 2 - Populations and Conservation
It Is the purpose of this Investigation to discover the re­
lative importance of the facte Included In the Lecture Sylla­
bus for Biological Science.
Each fact is to be evaluated in
terms of the contribution whloh you believe It makes toward
the understanding of a fundamental principle of biology.
Please interpret the word "understanding" within the limits
you believe to be imposed by the objectives of general ed­
ucation and the specific objectives of the area in which the
principle occurs.
The principles were taken from the Study
Guide for Biological Science.
You will find the principles
from each area in the study guide followed by facts taken
from corresponding areas of the syllabus.
Will you rate
eaoh fact aooording to the following key ?
Mark space 1 if you believe that knowledge of the fact
essential to an understanding of the
principle.
Mark space 2 if you believe that knowledge of the fact
I0 Quite Important to an understanding of
the principle.
Mark spaoe 3 if you believe that knowledge of the fact
is of average Importance to an understand­
ing of the principle.
Mark space 4 if you believe that knowledge of the fact
is relatively unimportant to an understand­
ing of the principle.
Mark spaoe 5 if you believe that knowledge of the fact
I0 unrelated to an understanding of the
principle.
THE SPECIFIC OBJECTIVES OF AREA 8 , UNIT 2
1. To understand the relationship between a species'
capacity to reproduce its kind and the factors of the
environment which resist increase in population else.
2 . To recognize the fact that human populations are sub­
ject to the same biologloal forces as are the popula­
tions of other organisms.
3.
To understand the significance of the conservation of
natural resources to human welfare.
PRINCIPLE I
The population size of a speoies is a result of the inter­
action between the theoretical capaolty of that speoies to
reproduce its kind (its biotic potemtial) and the environ­
mental resistance confronting the organisms comprising the
speoies.
1.

The physical and biological factors in the environment can
be thought of as constituting a resistance to the Increase
in numbers of living things.

1*15
2.
3.

4.

6.

Unlees the Individual living organism is adopted or can
consciously adjust Itself to unfavorable environmental
conditions, it cannot survive.
This prinoiple (that unless the individual living organ­
ism is adapted or can consciously adjust Itself to unfavor­
able environmental conditions, it cannot survive) applies
with equal effectiveness to populations of individuals.
Since all living things possess a tremendous capacity to
reproduoe their kind, the sl2e of animal or plant populations
fluctuates with the degree of environmental resistance ex­
erted.
This basic concept of interrelationships in the natural
world can be expressed very simply by the equation:
- F*produotlv« Capacity

pu ation — EKTiraaMMtai w im n ta

6.

7.
8.

9.
10.

11.
12.
13.
14.
15.

The idea of an organism's theoretical capacity to repro­
duoe oan be gained from the following example.
It has been
estimated that a single bacterium 1/ 20,000 of an lnoh long
and 1/30,000 of an inch thick, if allowed to reproduce to
the limit of its capacity without the restraining influence
of its environment, could, in one day's time, fill a pipe
one inch in diameter reaching from New York to San Franoieoo.
Within twenty-four hous this reproductive spree (of a single
bacterium) would result in four sextlllion baoterla.
We need not, however, limit our example to baoterla.
It
has been estimated for humans that if one husband and wife
had six oh 11dred and eaoh pair of children had six child­
ren, the entire world could be populated in nineteen gen­
erations.
The fourth generation would produoe 162 indivi­
duals whlld the nineteenth would consist of 2,324,522,934
individuals.
Biologist hypothesise that the failure or success of the
human race will depend upon the wisdom man shows in con­
trolling his reproduction quantitatively and qualitatively.
In this respect (ability to apply control measures to his
reproduction both qualitatively and quantitatively) man
differs from other living things, f o r he (man) oan apply
creative Intelligence to a problem whloh other living things
must leave to the action of non-consolous natural forces.
A population oan be compared to a living organism in several
respeots.
Like an organism, a population has a life history, it grows
in a typical fashion, undergoes changes that may lead tw
a division of labor among its members, ages and dies.
Like an organism it is an Integrated unit.
It meets the
forces of the envoronment as a whole rather than as a loose
assemblage of parts.
(A population) has an heredity.
The structure and composition (of a population) change
with increasing age even though at any one time it seems
very stable.

2a6
16.
17.
18.

19.

20

.

21.
22

.

26.

24.
25.
26.

27.

28.
29.
60.
61.

62.

The basic similarity (between organisms and populations)
Is especially evident when a population growth curve Is
compared to the growth curve of an Individual.
Under Ideal environmental conditions the growth of a pop­
ulation follows the same pattern of development as does
the growth of an individual.
Growth is slow at first, gradually increasing in rate
until 4 maximum is reached.
Almost Imperceptibly this
rapid rate of growth begins to slow down and after a time
the rate decreases more and more rapidly until at a later
date theme is no appreciable increase in the size of the
population.
When the growth of a population is plotted with either
weight or numbers against time, a typical 3 curve is se­
cured like that for the growth of an individual.
A population is defined as a group of living individuals
set in a frame that is limited; and defined in respect to
time and spaoe.
If more than one species is Included in the group, the
group is spoken of as being a mixed population.
Animal and plant communities are usually mixed populations.
In his efforts to understand the population aspects of group
biology, the biologist is concerned basloally with three
factors.
These factors are (1 ) the birth rate, (2 ) the
death rate, and (6 ) the dispersion within the population.
The birth rate, or populatlon-lnorease factor, takes into
consideration the theoretical reproductive capacity and
the realized reproductive performance of a speoies.
The distinction between them (theoretical reproductive
capacity a n d the realized reproductive performance) is
clear.
(For example), a population might have a theoretical re­
productive capacity of 20,000 offspring per year but a
realized peproduotive performance of only 5000 individuals
for fchs same period of time.
Statistics on human populations show that the range of re­
productive performance extends between an average maximum
of approximately 50 births per 1000 population per year to
an average minimum of approximately 15 birth per 1000
annually.
Countries populated by members of the oaucasold race tend
to have a lower birth rate than countries populated by noncaucasoide.
Studies also reveal that in humans the rate and success of
reproductive performance in a population are determined by
the age of the reproducing members.
(For example), mothers 19 years of age and under are the
most fertile and fertility decreases with increasing age.
The death rate, or populatlon-decreaee factor. Interest
the biologist from the standpoint of why organisms die and
why they die at a certain age.
It is a population principle that different phases of the
life history of a population have dlffefent and character­
istic death rates.

1*17
33.

34.

35.
36.
37.
38.

39.
40.
41.
42.
43.
44.
45.
46.
47.

48.
49.
50.
51.
52.
53.

If the cause of death (of a population) can be ascribed
to the environment, it follows that a more ootnplete know­
ledge of the environment can lead to reductions in the
death rate, If this is desirable.
There is a tendency for the industrialized cauoasoid count*ries of the world to have lower death rates, Ju3t as they
have lower birth rates.
(Conversely), a country with a high death rate also has a
high birth rate.
Although the human population may be declining In oertaln
areas on earth, in general the human population is increas­
ing in size at a relatively rapid rate.
Some biologist point out that the human race is actually
enjoying a "breeding storm" notwithstanding wars, famines
and disease.
In 1630 approximately 400*000,000 inhabited the earth. By
1830 this number had doubled. By 1900 the number ahd in­
creased to 1,600.000,000 and the total at present is over
2,000,000,000 with an annual Increase of 20,000,000 or
roughly one per cent.
It Is predicted that by 1999 there will be 3,300,000,000
people on earth.
The dispersion factor is oonoerned with the emigrations
and immigrations whloh ooour within a population.
If either (emigration or immigration) is excessive a
condition of depopulation or overpopulation oan take plaoe
within an area.
One of the most significant elements in the biological
environment of living things is population density.
(Population density) is defined as the number of organisms
per unit space they oooupy.
(Population density) has been shown to affeot the growth
form of a population.
Increased crowding of organisms in a population reduces
the growth rate and oan even bring about a decline in the
population.
If there is competition for food the feoundlty of the fe­
males in the population decreases with an Increase in pop­
ulation.
When the total environment is unsaturated, increased e m i ­
gration oaused by orowdlng leads to survival in the pop­
ulation because the organisms moving out find environmental
niches still unexplored.
When the total population is static, however, emigrations
from one plaoe to another lead to death.
(Finally), the age composition of a population reveals the
"youngness" or "oldness" of the population in terms of its
life history.
A growing and vigorous population contains a great pre­
ponderance of young organisms.
A stationary population has an intermediate number of young
as compared to old individuals.
A deollnlng population is characterized by a preponderance
of old organisms.
The social, eoonomlo, and polltloal implications of these
facts for human populations are manifold.

PRINCIPLE II

1*18

The conservation of natural resources Is a logical con­
sequence of m a n !8 understanding of the interrelationships
among living things and between the living and nonliving
parts of the environment.
1.
2.
S.

4.
5.
6.
7.
8.
9.

10.
11.
12.

13.
14.
15.
16.
17.

An understanding of ecological relationahops reveals the
lntrioaoy of the factors in the soll-water-plant-anlmal
complex.
It should be obvious that the welfare of human life on
earth is directly dependent upon an understanding of these
factors.
The study of food chains and the phases of ecological suc­
cession reveals the fact that a disruption of any one of
the links in a given sequence can seriously affect the en­
tire complex.
Man. (therefore), in his agricultrual and industrial pur­
suits must consider the biological and ecologloal principles
which underlie his activities.
He (man) should remember that he cannot conquer nature.
At best he (man) can merely cooperate with nature on the
terms and under the conditions she sets forth.
He (man) should constantly be aware of thp social, economic
and political implications of man-initiated disruptions of
the ecologloal pattern.
(Since) the human community is completely dependent upon
the earth’s crust and its resources, a prime objective of
human activity should be the wise use of these resources.
Outstanding geographers point out that any nation, if it
is to support its population and maintain a high standard
of living among its people, requires five classes of re­
sources.
First, it must have an abundance of fertile soil;
second, an adequate supply of minerals; a sufficient and
dependable supply of fuel and power; fourth, a sufficiency
of timber; a relatively high proportion of its people must
be of hereditarily high biological quality.
Of the resources listed fertile soil stands formost.
The food problems of the world with its ever-Inoreasing
population oan be solved only in terms of the basio medium
for food production, the soil.
Soil conservation (thus) becomes a matter of International
concern, since the unchecked depletion of the soil re­
sources through erosion and the consequent decrease in
food supply are ever present invitations for social unrest
and political upheaval.
Peaoe with hunger oannot be peace for long.
Closely related to soil conservation is the conservation
of forest, grasslands, water resources and wildlife. All
are a part of the soli-water-plant-animal complex.
The wise use of our forest, grasslands, and the land under
cultivation leads to better control of the water and wind
forces causing erosion.
Where forest, grasslands, and hedgerows exist, one will
find environmental conditions suitable for wildlife.
Where wildlife abounds man has an unexcelled recreational
outlet.

10.9

18o

19.

20.

21

.

22.

25.

Conservation through ecological engineering Is of Im­
portance to human welfare, whether in terms of his food
and nutritional needs or in terms of his mental and emotion*al well-being.
With regard to mineral, fuel, and power resources. It should
be recognised by all that America has become great beoause
of her original store of geographic goods and not neoessarlly
beoause of her sooial and political institutions.
Her natural resources of coal. Iron, oopper, and other baslo
minerals together with her resources of oil, timber, and
ground water were the greatest on earth and upon these re­
sources was constructed the greatest Industrial civilization
known to man.
As a noted eoonomlst tftates It, "The greatness of America
has been the greatness of our continent- Its sweep, Its
varied resources, Its abundant vitality.
We have what
other nations go to war to obtain.
And If we are determin­
ed to defend it from attack, we should be equally determin­
ed to defend It from our own abuse?
To promote successfully the conservation of our natural
resources, whether soil, mineral, fuel, timber, or human,
requires the develbpment within aaoh of us of an ecologloal
oonsoienoe.
In the words -of the late Aldo Leopold, N The praotioe of
conservation must spring from a conviction of what Is
ethically and esthetloally right, as well as what Is eco­
nomically expedient. A thing is right only when It tends
to preserfe the integrity, stability and beauty of the
community and the oommunlty includes the soil, water, fauna
and flora, as well as people.

AREA 9 - EVOLUTION

h20

It is the purpose of this Investigation to discover the relative
Importance of the facts Included In the Lecture Syllabus for
Biological Solenoe.
Each fact is to be evaluated In terms of
the contribution whloh you believe It makes toward the understanding of a fundamental principle of biology.
Please Interpret
the word "understanding" within the limits you believe to be im­
posed by the objectives of general education and the specific
objectives of the area in which the prlnoiple oocurs.
The
principles were taken from the Study Guide for Biological Solenoe.
You will find the principles from each area in the study guide
followed by facts taken from corresponding areas in the syllabus.
Will you rate each fact aooordlng to the following key ?
Mark spaoe 1 if you believe that knowledge of the fact
is essential to a n understanding of the
principle.
Mark space 2 if you believe that knowledge of the fact
is fltfA-te- important to an understanding of
the principle.
Mark space 5 if you believe that knowledge of the fact
is of average importance to an understanding
of the principle.
Mark spaoe 4 if you believe that knowledge of the fact is
relatively unimportant to an understanding
of the principle.
Mark spaod 5 if you believe that knowledge of the fact
is uqra^atad to an understanding of the
principle.
THE SPECIFIC OBJECTIVES OF AREA 9
1. To understand the development of the concept of organlo
evolution from the historical viewpoint.
2. To understand the history of the development of living
things in the course of geologic time.
S.
To recognize and appreciate the validity of the various
sources of evidence supporting the fact of organlo
evolution.
4. To understand the Theory of Natural Selection.
5. To study the evolution of man.
PRINCIPLE I
Every kind of animal and plant living today has desoended,
with modifications, from organisms which have lived in the
geologic past.
1.

Biological evolution is a principle which states that the
kinds of animals and plants living today have descended
from different forms that lived in the past.

h21
2.

The essential point (concerning biologies! evolution) is
that species are not static but have changed in the past,
are changing now, and will continue to change in the’future.

3.

Biological evolition is concerned with explaining the changes
that have oocured in living forms from the first primitive
living substance to modern organisms.

4.

Bibloglcni evolution does not attempt to explain how life
originated.

5.

No one knows when or how the first forme of life appeared
on earth, but there are several interesting theories.

6.

The 8peolal Creation Theory states that all living things
were created within a short spaoe of time Immediately after
the earth was made.
A n things were created at this time,
and there has been no change in any of the living things
since this time.

7.

According to the Spontaneous Generation Theory it was once
generally believed that, given suitable environmental
conditions, non-living matter could form into complete,
complex living things such as Insects, frogs, and fish.

S.

Aooordlng to Van Helmont, a sixteenth century Butch scientist,
the oomblnatl on of solldd linen and cheese would produce mice.
The Hlle river mud plus the heat of the sun supposedly was
able to produce both mice and rats.

9.

The Physico-chemical Evolution theory assumes that at one
time during the history of th? world conditions were such
that very simple forms of life arose through the combination
of non-living matter.

10.

The physico-chemical theory is somewhat similar to that of
spontaneeas generation.
The difference is that aooordlng
to spontaneous generation the production of living things
from nonliving occurs constantly while according to the
physico-chemical evolution theory it occured only at some
remote time in the earth's history and has not happened
slnoe.
Also spontaneous generation supposes that complex
organisms arise from non-living matter, while the physico­
chemical theory assumes that only very simple forms of life
arose in this fashion and thAt all modern, complex forms
have evolved from the primitive forms.

11.

(These) preserved forms, the fossils, have told man most of
what he knows concerning the evolutionary history of life.

12.

The earth is constructed of a central core and a crust that
lies outside the core.
The crust is a shell of rook that
varies in thickness.
In places it is covered with water
forming oceans.
In other places the rook is exposed, form­
ing the continents.

i|22
13

o

14.
15.

16.

1?.
18.
19.

20

.

.
22 .
21

26.
24.
26.
26.

27.
28.
29.

The rook of the continents Is exposed- to 'the action of wind,
rain, temperature changes, and plants and anirrais. which
result In a gradual disintegration or "weathering" of the
rook.
The loose material (thus) formed (by weathering action on
rook) covers the earth as the soil.
Some (of this) soil is washed away by rain and streams and
eventually deposited as sediment in lakes and oceans, where
it settles to the bottom to form layers of mud or sand. AS
time passes more layers are added on top of the earlier-formed
ones and eventually all of them become rock because of chemloal
changes and the oompresslng effect of weight,
nock (formed by the deposition of water borne deposits is
called sedimentary rock because of the materials out of whloh
it Is made and also Is called stratified rock beoause It Is
formed In layers.
Weathering, when continued over millions of years, gradually
wears away the exposed rooks and the continents beoome flat­
tened.
As the continents wear away the edges of the ooeans beoome
filled with sediments and the water of the ocean gradually
overflows the land.
The continents as a whole also rise and sink slowly over
long intervals of time, and when they sink the water of the
ocean Inundates parts of the oontlnent.
(Beoause of the changing relationship between land and water)
great arms of the ooean oover vast areas of the continents.
(Hudson Bay is an example of an arm of the sea having moved
In ovefc a vast area of oontlnent).
Into (these) shallow continental eeas more sediment Is carried
and more, sedimentary rook Is formed,
eventually the oontlnents
rise again.
The ooeans recede from the continents and the
sedimentary rock becomes dry land.
Usually during (these) periods of uprising oontlnents, the
earth's surfaoe buckles in places and mountains are formed.
Following the rise of the. oontlnents and the formation of
mountains weathering again begins its leveling aotion through
rook disintegration and sedimentation.
This oyole of rising and sinking continents has ocoured many
times In the past history of the earth and during each oycle
new layers of sedimentary rook cure formed.
The layers of sedimentary rook laid down at the beginning of
a oyole are always underneath those laid down later and also
the layers of an earlier oyole are always beneath the layers
of a later cycle.
Occasional exceptions to this rule (law of superposition)
ooour when, during mountain formation, the buckling of the
earth results In a folding of the rook layers.
During the time when sedimentary rook is being formed, animals
and plants are occasionally burled within the sediment. Some
r O t these forms are preserved.
This (preservation) Is particularly true of the hard skeletal
parts of organisms, though sometimes even the softer body parts
or their form are preserved.

1*23

30.
31.

32.

33.

34.
35.
36.
37.

38.
39.
40.
41.
42.
43.

44.
45.

46.
47.

(These) preserved animal and plant res.Tr..ins are called fossils.
With the lifting of the continents the roc 1:3 containing the
fossils beoome exposed to weathering and as the rocks wear
away, some of these fossils are exposed g o that man can find
them and study them.
By means of a study of the sequence In time in which the rook
layers have been formed plus a study fif the fossils contained
In the rocks, is has been possible to trace the history of
living things on earth.
By various means it has been possible to determine the approx­
imate age of the rocks, with.the result that a time scale has
been made of the history of the e a r t h ’s surface and of the
history of life on the earth.
This is known as the Geologic
Time Scale.
Copy of Geologlo Time Scale as given on page 217 of Syllabus
for Biologloal Solenoe.
What ever the cause or the manner of the origin of life it
is generally agreed that the fiBst forms of life were com­
paratively simple.
It has been suggested that these first living things were
protein in nature and that they had the ability to use in­
organic sources of energfc.
There are certain bacteria living today that do not need
plant food (produced by the action of chlorophyll) as a source
of energy, bqt oan obtain the energy thet require by causing
certain chemical reactions in inorganic matter.
The first living organisms were probably of this sort (similar
to the bacteria which do not depend upon plant food) and later
evolved into forms that utilized the sun as a source of energy.
The development of chlorpphyll or a chlorophyll-like substance
probably oooured very early.
These forma (containing chlorophyll or a chlorophyll-like
substanoe) were then able to capture the energy of the sun
and to store this energy in the form of food.
No one knows at what stage the substance of these early living
things became protoplasm as we know it today, nor can we say
when this protoplasm became cellular.
The early stages of evolution are lost in antiquity, but it
seems reasonable to assume that they oocured very early in
world history.
(It is also reasonable to assume) that af;ter the appearance
of simple.cellular plant-like forrs, life divided into two
streams.
One of these streams produced the modern plants
while the other resulted in the modern animals.
There are forma living today that are neither plant nor
animal In the strict sense.
(Euglena is an example of an organism that is neither plant
nor animal in the strict sense).
It has animal traits such
as a gullet and a food vacuole and also the characteristic
plant trait, chlorophyll.
The first animals were the invertebrates and of these the
slngle-oelled Protozoa appeared first.
The sequence of development of the remaining Invertebrate
types Is in doubt, but on the basis of structural complexity
it was probably as follows. Afcter the single-celled Protozoa
came the colonial Protopoa.

h2b
40.
49.

50.
51.
52.
53.

54.
55.
56.
57.
58.
59.

60.
61.
62.
63.
64.

.
66 .
66

67.

Colonial Protozoa are made up of aggregations of cells all
of the same type (showing no differentiation).
The colonial stage was probably followed by ©. differentiation
of certain of the cells (making up the oolony) to bring about
dlvldlon of &abor.
(Differentiation means that) within a cluster of cells making
up the oolony some would be specialized for food getting,
others for reproduction and still others for other functions:
The next step (following differentiation) was the arrangement
of these specialized cells into layers.
The sponges represent the stage In evolution in whloh special­
ized oells are arranged Into layers, being made up of loosely
Integrated cells a r r a n g e d in'an outer and an Inner layer.
The inner layer (In animals with two cell-layers) functions
mainly In food getting while the outer layer Is primarily
proteotlve, but also oontains sensitive oells that oan resond to environmental stimuli.
he Coelenterates represent the next probable evolutionary
advance (above the sponges).
{In Coelenterates) the oells within the two cell layers be­
come more closely Integrated so that they may be called
tissues.
(In Coelenterates) the outer layer Is protective and sensitive,
while the Inner layer is concerned with digestion.
A third cell layer appears next between the original two to
Increase the complexity of the organisms.
The modern flatworros are representatives Of this evolutionary step.
Flatworm embryos contain an external cell layer, the ectoderm,
an Internal cell layer, the entoderm, and a layer in between
known as mesoderm.
The eotoderm (In flatworm embryos) develops into an outer
layer whloh is still primarily proteotlve In function and
also retains its ability to receive stimuli from the external
environment.
The inner eotoderm (in flatworm embryos) beoomes the lining
of the digestive traot and Is digestive In function.
(In flatworma) the mesoderm in the middle develops into musole
and other internal body organs that make up the bulk of the
organism.
The next evolutionary advanoe (over the flatworms) was the
development of segmentation, as In modern annelid worms.
Segmentation is where the parte of the body are repeated in
a serial pattern from anterior to posterior.
The arthropods such as the orab, orayflsh. Insects, and
spiders probably evolved from the early primitive annelids,
for they retain the segmentation of the annelids to a marked
degree.
(The Arthropods added many new features (to those of the
annelids) including.an external skeleton of ohitln and Jointed
appendages.
The mollueks, suoh as the oyster and the olam, become special­
ized in the development of an outer protective shell.
The eohinoderms evolved with a five-rayed body pattern and
a special type of looomotlon by means of tube feet.

§

68.
69.
?0.
71.

72.
73.
74.
75.
76.
77.
78.
79.

60.
81.
82.
83.

84.
65.
86.

One should not conclude from a discussion of the sequence
of evolution that it occured in strictly serial fashion, be­
ginning with the protoeoa.
Suoh is not the oaee.
The exact sequence of evolution is unknown.
It is generally agreed that evolution has not proceeded in
a straight line, but rather that it has branched like a tree,
Following the analogy of the tree, the earliest forms of life
would represent the base of the trunk.
The trunk Immediately
splits into two main stems, one stem becoming the first ani­
mal forms and the other stem the primitive plant forms. The
base of the animal stem represents the primitive Protozoa
from whioh a branch extends laterally to represent the de­
velopment of the modern Protozoa. Another branch represents
the modern sponges. The main stem continues upward as the
primitive ooelenterates and from here several branches di­
verge.
One branch leads to the flatworms and roundworms;
another to the annelids, andther to the annelids, and another
branches to form the eohinoderms and the chordates which
evolve into the vertebrates.
The annelid branch separates
into two smaller branches, one becoming the arthropods and
the other the mollusks.
The vertebrates evolved from the Invertebrates.
The vertebrates appeared early in the history of life on
earth.
The vertebrates appeared about 550,000,000 years ago.
The vertebrates appeared during the Paleozoic Era.
In general (vertebrate) evolution was directed toward a type
of animal having greater looomotory powers than the in­
vertebrates possessed.
The Invertebrates were sluggish, slow-moving or sessile
animals, while the vertebrates became fast moving and agile.
It is probable that the first vertebrates appeared in fastflowing fresh water streams where swimming powers were es­
sential to prevent being swept into the seas.
The adaptations that developed in the vertebrates include
an internal supporting axis, the vertebral oolumn, segmented
body musoles that permitted a lateral bending of the body
to attain fowward propulsion and fihs to give leverage for
the muscular action.
The ostraooderms are the most primitive vertebrates known.
The ostraooderms lived about 450,000,000 years ago.
The ostraooderms lived during the Paleozoic era on the botton
of fresh water streams.
The ostraooderms had fish-like bodies and tails that ranged
from six inches to one foot in length, and they were covered
with thick bony scales.
The mouth was a transverse slit and
Jaws were absent.
In many ways the ostraooderms resembled the modern oyolostomes, whioh are the most primitive of modern fish.
The ostraooderms or their relatives gave rise to the sharks
whloh represent the next step in vertebrate evolution.
The mddifloatlons (of primitive ostraooderms appearing in
sharks) include the development of Jaws with teeth, the loss
of the heavy armor and the development of fins.

87.
88.
89.
90.
91.
92.
93.
94.

9b.
96.
97.
98.

99.
100.
101.
102.
103.
104.

106.
106.

The Jaws (in sharks) probably developed from the first pair
of gill arches.
(The teeth in sharks) probably developed from the scales
that covered the surface of the body near the mouth.
Gill arches are cartilaginous or bony supports for the gills
and lie Just behind the mouth on each side.
(In sharks the first pair of gill arches) one on each side,
moved forward, became hinged in the middle and took on the
new function of opening and closing the mouth.
(In sharks) the soales lying near the edge of the mouth moved
in to rest upon the Jaws and become teeth.
The transition from gill arch to Jaw bone is evident in the
development of embryos and the similarity of scales to teeth
oan be seen on modern sharks.
The sharks also developed paired fins.
The acquisition of Jaws, teeth, and paired fins enabled the
sharks to leave the bottom of the streams and swim freely
in the water.
The fine made oontrol of body movements pos­
sible and the Jaws and teeth were useful in catching prey.
These mQdlfloations made greater freedom of movement pos­
sible and the sharks migrated into the oceans where they are
fougdL today.
The next advanoe (above the sharks) in the evolution of the
vertebrates was the appearance of the bony fish.
(These) fish developed a
skeleton of bone while the forms
that evolved into modern
oyolostomes and sharks retained the
cartilage.
The fish that developed their skeletons of bone are Important
beoause they not only produced the myriads of modern fish
and salt Water fish, but also gave rise to the land living
vertebrates including man.
The bones of these early(fish) forms made up the internal
framework of the body and also covered the tops and sides
of the skull.
The pattern of skull bones laid down in these (early) fish
oan be traced with modifications into almost every later
vertebrate type.
Even the parts of the human skull can be compared with the
individual bones of these early fish skulls.
An Innovation Just as important to bertebrate evolution as
the bony skeleton appeared (in the primitive bony fish). This
was the development of paired lungs.
It is probable that lungs developed fluring a time when seasonal
oklmatlo changes were extreme, resulting in a periodic drying
up of streams and ponds.
(During a time of extreme seasonal cllmatio changes resulting
in the drying up os ponds and streams) a fish with lungs
would have an advantage over those without lungs in being able
to come to the surfaoe and gulp air, when pools became
stagnant, .foul, and deflolent in oxygen.
The early bony fish with lungs branched into three groups,
the ray-finned fish, the lung fish, and the lobe-finned fish.
The ray-finned fish evolved into the modern fish.

b27
107,
108.
109.

110 .

.

111

.

112

113.
114.
115.
116.

117.
118.
119.

.

120

121.

.

122

123.
124.

The lunge of the ancestors (of the modern fish) became
modified into ah air sao or bladder that moved to the dor­
sal side of the body cavity.
(The air sao or bladder in modern fish) is used to change
the spedlflo gravity of the body enabling the fish to change
its elevation in the water with ease.
The lung fish of today inolude three forms.
One type lives
in Australia, the second in Africa and the third in South
Amerloa.
(Modern lung fish) live in ponds and streams that dry u&
periodically and when this happens the fish burrow into
the mud of the botton.
There they remain until water re­
turns to the pond.
The lobe-finned fish are very similar to lung-fish.
The
only significant difference is that the lung fish remained
stationary in the evolutionary sense while the lobe-finned
fish evolved into land living vertebrates.
The characteristics of the lobe-finned fish that make pos­
sible the transition from water t o land Include the lungs,
an open connection between the external noatrlls and the
throat, and fins that were rounded and strong, containing
both bone and muscle.
The fundtlon of the lungs in an air breathing animal is
apparent.
The internal connection of the nostrils to the throat (in
the primitive lobe-finned fish) permitted breathing through
the nostrils.
The bone-eupported fins (of the primitive lobe-finned fish)
gave sufficient support to permit locomotion across dry
land.
(The struoture of the skeletal support of the fins of the
lobe-finned dish is as follows) One bone connects with the
shoulder skeleton.
Extending from the end of this bone
within the fin are two bones lying side by side.
From the
ends of these bones a series of small bones branch to sup**
port the Tree end of the fin.
The single bone that oonneots with the pectoral girdle is
comparable to the humerous of land animals including man.
The paired bones (below the humerous in lobe-finned fish)
are similar in position to the hand and finger bones.
The paired bones (below the humerous in lobe-finned fish) is
oomparable to the radius and ulna (of land animals).
The lobe-finned fish lived during a time when seasonal changes
were great, and it is believed that some of them were forced
to beoome adapted to living on land or die.
(Some of the lobe-finned fish) became adapted and evolved into
amphibians.
,
The amphibians whloh evolved drom the lobe—finned fish ranged
in else from about two feet in length to individuals equal
in size to modern orooodlles.
They had long, slim fish-like
bodies with long tails.
Paired limbo supported these bodies
by means of an internal bone structure similar to that found
in the human skeleton.
Ih amphibians lungs replaoed the ancestral gills.
(In amphibians) air was forced into the lungs by swallowing.

1*28

125.
126.

127.
128.

129..

130.
131.
132.

133.
134.

135.
136.
137.
138.

139.
140.
141.

The ear m a d e Its first appearance in amphibians.
One of the a n c e s t r a l gill slits persisted as a tubular
o p e n i ng f r o m the throat to the side of the head.
This
tubular ope n i n g known as the euetachian tube, was closed
over at the outer surface by a membrane, the ear drum.
Just b e n e a t h the membrane a bony remnant of one of the
g i l l a r o h e s served as a connecting link between the ear
d r u m a n d the Internal ear.
V i b r a t i o n s of the ear d r u m were caused by sound waves and
these v i b r a t i o n s caused movements in the ear bone, w h i o h
in turn m o v e d parts of the inner ear thus setting up nerve
impulses w h i c h were carried to the brain.
While the success of am p h i b i a n s in making the transition
f r o m w a t e r to land w a s a tremendous evolutionary step it
w a s not q u i t e oomplete.
The a m p h i b i a started the parade
to land, but they never quite succeeded in leaving the
w a t e r completely, f o r w h e n it came time to reproduce they
h a d to r e t u r n to water.
M o d e r n amphibia, a m o n g them the frogs end toads, are still
d o i n g this (returning to w a t e r d u r i n g breeding activity)
w h i l e m a n y of the salamanders live permanently in water.
R e p r o d u c t i o n of a n y v e r t ebrate animal must necessarily
ooour in water.
Eggs a n d sperms need water to unite. The
embryo n e e d s w a t e r in w h l o h to develop.
The p r o b l e m was to evolve a m e c h a n i s m for creating this
a q u a t ic environment (necessary for vertebrate reproduction)
on land so that rep r o d u c t i o n and development could take
plaoe.
Some a m p h i b i a lay eggs in moist burrows, some use rainfilled h o l l o w s in trees, a n d one m o d e r n toad deposits its
eggs in little pits o n its back.
None of the (amphibian) schemes (for obtaining an aquatio
e n vironment for fertilization) was very successful and the
amphibia, w h l o h started the procession to land, fell back­
w a r d in t h e e v o l utionary race.
It r e m a i n e d for the r e p t i l e s to solve the p r o b l e m of r e ­
p r o d u c i n g on land.
T h e r e p t i l e s evolved f r o m the amphibia.
In r e p t i l e s the land egg developed and they were freed
f o r e v er f r o m the necessity of v i s i t i n g ponds a n d streams
for reproduction.
The e g g that d e v e l o p e d in the reptiles consists of a water
filled sao, the amnion, that surrounds the developin g em­
bryo, a y o l k sac containing food suspended from the embryo,
a n d a n o t h e r sao that serves as a respiratory organ.
All
of this is surrounded by a tough, porous proteotlve shell.
The(land) e g g contained all of the environmental conditions
normally f o u n d in jponds and streams and could be 1 a id any­
w h e r e on land.
Internal co p u l a t i o n d e v e loped (in reptiles) as a necessary
r e p r o ductive function to b r i n g the sperms and eggs together
in a moist medium.
T h e r e p t i l e s made use of the freedom provided by this new
r e p r o d u c t i v e meoha n i s m a n d evolved into many different types
w h l o h ent e r e d p r a o t loally all of the available land habitats.

h29
142.
143.

144.

145.
146.
147.
148.
149.
150.
151.
152.
153.
154.
155.
156.
157.
158.
159.
160.
161.
162.
163.
164.

Some reptiles developed wings and flew while others turned
baok Into the water.
The reptilian body as a whole became adapted to land living.
A thick, tough, horny body covering prevented excessive
water evaporation.
The heart became more efficient and
the brain more highly developed, and many other internal
organs advanced beyond those of the amphibians.
The oldest known birds were scarcely more than feathered
reptiles.
The birds evolved from the reptiles.
The skeletons (of primitive birds) was typically reptilian,
with a long tall and teeth attached to the jaws.
Each wing
had three ringers extending from it and these bore claws.
The only reason too identifying these skeletons a 3 birds is
the presence of a faint impression of feathers.
It is still questionable how flight evolved.
One theory (as to how flight evolved) states that these early
birds lived in trees and learned to glide from branch to
branoh.
Another theory(as to how flight evolved) states that the
anoestoral birds ran along the ground and with wings outstreaohed soared into the air.
The major structural changes that occured during the
evolution of birds are practically all adaptations to aid
in flight.
Feathers serve to streamline the body and to act in the
wings and tall as resistant surfaces to push against the
air.
The feathers (of birds) are probably modified reptilian scales,
The brain (of the birds) enlarged, but without an Increase
in Intelligence.
The parts of the brain that enlarged were concerned primarily
with sight, balance and the musohlar coordination needed for
flight.
The sternum (of birds) increased in size to afford greater
area for wing muscle attachment and the bones hollowed out,
making the body lighter.
The eyes developed into efficient organs for sight. The
teeth were lost and a beak developed.
The creatures (birds) also became warm blooded and correlated
with this was the development of an efficient circulatory
system that brought a good supply of oxygen to the tissues.
As a part of the olroulatory system (of birds) a four chamber­
ed heart developed.
.
The four chambered heart effectively separated the oxygenated
blood from the nonoxygenated blood and so increased the
efflolenoy of oxygen distribution.
The reptiles had scarcely began their long evolutionary
history on earth when the mammals first appeared.
The first mammals were modifications of a primitive group
of flesh eating reptiles.
The first mammals were small and probably were no bigger
than modern mice and rats.

1*30
165.
166.
167.

168.
169.
170.
171.
172.
175.
174.
175.
176.
177.
176.

179.
180.
181.
182.

(The early mammalian) teeth were sharp and adapted for flesh
eating, but It Is believed that they fed mostly on Insects
and worms.
The brains (of the early mammals) were better than those
of the reptiles, but not particularly well developed In
comparison with modern mammals.
Some of the characteristics that developed In mammals id—
elude a modification of the reptilian mode of reproduction,
warm blood, a better developed brain, and a change In the
position of the limbs.
Mammals retain their young within
the body of the mother until they are quite well developed.
They also have speolal glands, the mammary glands,'tthlon
secrete milk for the nourishment of the young.
Tney are
warm blooded and have a gour chambered heart so that the
production of energy is higher than In reptiles.
The brain
Is large, resulting In a high degree of Intelligence, and
the limbs are directly under the body with the knees directed
forward and the elbows back.
This position of the limbs
supports the body and enables the development of rapid, looomotlon.
The teeth of mammals are quite specialized, and the
ear drums are sunk below the surface of the head.
Hair is
a oharaoterlstlo body covering.
There are three major groups of mammals: the monotremea, the
marsupials and the plaoentals,
The monotremea are found only In Australia and Tasmania.
The monotremea are the most primitive of all mammals.
(The monotremea) still have many reptilian characteristics,
including the habit of laying eggs whloh hatch In a nest.
The marsupials have a pouch on their abdomens In whloh they
carry their young.
The young (of marsupials) are born prematurely and finish
their development hanging onto a nipple within the pouch
(on the mothers abdomen).
The kangaroo is the most generally known marsupial, though
there are many others, including the opossum In the United
States.
Practically all (of the marsupials), however, are confined
to Australia and adjacent areas.
The placental mammals retain their young within the body of
the mother longer than the monotremes and marsupials,
(In placental mammals) nourishment for the embryo Is pro­
vided by the placenta.
(In plaoental mammals) this longer period of development
before birth presumably gave these mammals an advantage for
they have flourished and evolved into many successful animal
types. Including man.
The lnseotivores are small, primitive, insect eating paaoentals such as the mole and shrew.
The carnivores are the flesh eaters and include the seals,
walruses, bears, cats, dogs, weasels, raccoons and others.
The herbivores are the hoofed animals.
Some (herbivores), such as the pig, cattle and deer, have
two hoofs on each foot, while others, suoh as the horse have
but one hoof per foot.

1*31
183.
184.

Bate are flying mammale.
(In bats), a flap of ekin extends between the elongated
finger bones and from the arm to the body to form the wings.
185. Whales are the largest of mammals.
186. Whales are entirely aquatic spending their entire life from
birth to death in the water.
The body has become streamlined
and the fore limbs have beoome flippers. The hind legs are
gone.
A fish-like tall aids In swimming.
187. The primate8 are the group of mammals to whloh man belongs.
188. All of the primates are tree dwellers except a few forms
like the baboon and man, who normally live on the ground.
189.
The structural characteristics of primates are adapted for
a life in trees.
190.
(The structural oharacterlstlos) of primates include flexible
limbs that permit climbing and swinging through the trees.
Both the hand and the foot are grasping organs.
The thumb
and big toe are opposable to the other fingers. Most primates
have a tall that Is used In some as a grasping organ, though
in the man-like apes and man the external tall Is missing.
The teeth are reduced in number as compared with those foung
In other mammals.
191. The eyes of primates are well developed
192.
Stereosooplo vision, whloh permits the formation of a single
Image from the two eves, appears (in the primates).
193.
(Stereosooplo vision), gives greater depth of field and great­
er perspective.
194.
In the monkeys, apes and man a special area, the central pit,
Is present on the retina that enables these animals to see
greater detail.
196.
Tin the primates) the sense of smell Is degenerate.
196.
(The primate) brain Is highly developed, resulting in a
high degree of intelligence.
197.
There are three main groups of primates: the lemurs, tarsius
and the anthropoids.
198.
The lemurs are small primitive primates.
199.
The lemurs live In Asia and Afrloa.
200.
Tarsius Is (also) a (small primate).
201.
Tarsius lives in East India.
202m
Taralus is Intermediate In development between the lemurs
and the anthropoids.
203.
The anthropoids include the monkeys, the manlike apes, and
man.
204. The monkeys are separated Into two groups. One, the New
World monkeys, lives in South America, the other group,
the Old World monkeys, In Asia and Africa.
205. Monkeys are noted for their ourloslty.
206. This (ourloslty of monkeys) is due to a high degree of
intellectual development that supposedly Is the result of
the combined effeot of the well developed brain, the ability
to sit up, the opposable thumb, and keen eyesight.
207. A well developed cerebrum Is essential for Intelligencer
208. The ability to sit up supposedly has contributed to the
development of intelligence by freeing the hands for use
in handling objects.

k&2
209.

The opposable thumb enables the monkey to handle objects.

210. The keen eyesight (of monkeys) enables him to see more
211

.

212

.

213.

214.
215.

216.
217.
216.
219.

.

220

221.

.

222

223.
224.
225.
226.
227.
228.
229.
230.

things to be ourlous about.
Man also has all of these character!sties (which the monkey
has), and It Is believed that man's intelligence is the
result of the futher development of the same kinds of traits
that are found In monkeys.
The manlike apes include the gibbon, orangutan, chimpanzee
and gorilla.
(The manlike apes) are the closest of all the primates to
man In physical development.
The skeleton (of the manlike apes) Is very similar to man's.
The ohest (of the manlike apes) Is broad rather than narrow
as It is In the monkeys and other mammals.
(In the manlike apes) the arms are larger and the legs are
shorter than In man and the big toe Is opposable, but the
hand Is very similar to the human (hand).
These animals (manlike apes) have an erect posture when
swinging through the trees, whereas on the ground they
usually progress on all fours.
Man differs from the apes in many ways, but the differences
are all differences of proportion of basically similar parts.
The major differences (between man and the apes) are related
to methods of locomotion and to the growth of the brain.
Man is ereot and walks bn the ground.
This ercot posture
has resulted in a curved backbone that brings the trunk
and head directly over the hips and thus centers the weight
over the lags.
The foot (of man) is modified by'a shortening of the toes
and the expansion of the heel bone as a prop in back. The
big toe is no longer opposable but it in line with the other
toes. Man's foot is adapted for walking and is no longer
a grasping organ.
The hand Tof man) differs less from the ape*s hand.
It is
still primitive and very useful as.a grasping organ. The
thumb remains opposable.
Man's face is shorter than the apes; the nose is more pro­
minent and a ohln projeots from the lower Jaw.
The teeth (of man) are smaller and weaker than the ape's.
The (human) brain is muoh larger, being two or three times
greater than in apes, and man is more intelligent.
All primates including man evolved from a common ancestor.
(The oommon ancestor of all primates) was one of the most
primitive of mammals, the aboreal Insectlvore.
Each of the modern types of primates evolved along a sep­
arate path resulting in lemurs, tarsius, monkeys, apes and
man.
(Thus), man it should be understood, did not evolve from
modern monkeys or apes, but both (man and modern apes)
evolved along separate paths from a common ancestor. .
The earliest man probably originated during the Pliocene
period of the Cenozolo era and evolved into modern nan
during the Pleistocene period.

t o

221.
232.
233.

224.
225.

226.
227.
228.
229.
240.
241.
242.
242.
244.

245.
246.
247.
248.
249.
250.
251.
252.
252.

254.

The Pleistocene period was approximately one million years
long and wae characterized by periods or glaciation.
(During the Pleistocene period; there were probably four
successive ite sheets, with long periods of temperate to
warm climates between the periods of glaciation.
The warmer periods (of the Pleistocene) were from ten to
hundreds of thousands of years in length.
The most positive evidence of m a n ’s evolution consists of
a number of human fossils.
(The human fossils) Include the Piltdown man, (Eoanthropus
dgwsonl). the Heidelberg man (Homo heldelber«ensle). the*^
ava man (Pithecanthropus erec tusT. the Peking man (Sinan­
thropus peklnenslsVj the Neanderthal man (Homo nennderthalensis) and the tfro-Magnon man (Homo saplensT~~'
This list (above) does not include all of the human fosfclls
but does include the best known ones.
There is no final agreement as to the exactsequence In
which these early men appeared.
It Is not certain that each of the foBsil men represents
a step In a single evolutionary path.
It is possible that early in human evolution there was a
divergence so that two or more lines of human evolution
may have oocured.
The age of the rocks in which the fossils were found in**
dloate that the Piltdown and the Heidelberg man lived during
the early Pleistooene period.
The Java and Peking men were probably contemporaneous during
the middle Pleistocene.
The Neanderthal and Cro-Magnon men lived during the late
Pleistocene, with the Cro-Magnon man appearing somewhat later
than the Neanderthal type*.
The Piltdown man was found in Piltdown, Sussex, England In
1912.
The (Piltdown) fossil dates from the first interglacial stage
in early Pleistooene and consists of pieces of skull, most
of a lower jaw, nasal bones, a canine tooth and two cheek
teeth.
A few crude tools were found associated with the bones (of
Piltdown man).
The skull of Piltdown man is modern in type except for the
bones, which are twioe as thick as modern man.
The brain capacity (of Piltdown man) Is 1200 ml.
The brain capacity of modern man ranges from 1200 to 1500 ml.
The Jaw (of Piltdown man)is apelike and h^s a retreating chin.
The canine tooth (of Piltdown man) Is also apelike while the
oheek teeth are a type that could be found in either an ape
or in a primitive man.
^
The Heidelberg man Is represented by a lower jaw with attach­
ed teeth.
,
(The Heidelberg Jaw) was found near Heidelberg, Germany.
(Heidelberg Jaw) was reoovered from rock of early Pleistooene
formation.
(Heidelberg Jaw) is apelike In that it is large in size and
heavy in build and has no chin.

h3h
255.
256.
257.
256.
259.
260.

261.

262.
265.
264.
260.
266.
267.
266.
269.
270.
271.
272.
275.

The teeth and dental arch (of Heidelberg Jaw) are human
in character.
(Heidelberg Jaw) ahowe some similarities to the Java man
and to the more recent Neanderthal man.
The Java man dates from the middle Pleistocene about 500,000
years ago.
The firet find (of Java man) made in the East Indies included
a skull cap, three teeth, and a femur.
Java man had some features that were human in character and
some that were apelike.
The human characteristics of Java man are as follows:
The
brain capacity of the skull (940 m l . ) is intermediate be­
tween apes (600 ml.) and modern humane (1200 to 1500 ml.).
The median sagittal orest is absent.
This is a prominent
ridge of bone that extends from fromt to back along the
middle of the skull In some apes.
The femur has a straight
shaft, and the position of the articular surfaces Indicates
that the muscle attachments were for an erect posture.
The
teeth are more human than apelike.
The apelike characteristics (of Java man) Include heavy brow
ridges.
Also the forehead slopes back from the brow ridges
whloh makes the vault of the skull low. The canine tooth
of the lower Jaw fits into a space between the teeth of the
upper Jaw.
The wisdom teeth are not reduced.
There is no
ohln, and the hole through which the spinal cord enters the
oranlum is visible from behing. This is not true of modern
skulls.
The Peking man was found in a limestone cavern near Peking,
9hina.
(At the Peking find) the remains of three dozen individuals
of both sexes and both young and adults were discovered.
There are some differences between the Peking man and Java
man, but they are not any greater than the differences among
modern races of men.
The Peking man was a tool user because crude stone tools
were found assoolated with the bones.
Likewise remnants of fires were found, indicating that.the
Peking man had learned its use.
Many brain oases had been opened from the botton, evidently
by man himself.
This is Interpreted to mean that the Peking
man was a cannibal.
The Neanderthal man was the first human fossil discovered.
The first discovery was made in the Neanderthal Valley near
the Ruhr district in western Germany in 1856.
Since (the original discovery) many skeletons have been
found in the following locations: Western Europe, Gibraltar,.
North Afrioa, Italy, Croatia, Palestine, and Russia.
(The many locations in which Neanderthal finds have been
made) indicates that the Neanderthal man had spread all over
Europe.
(Neanderthal man) had heavy brow ridges, a reoeding fore­
head and a low vault to the brain case. There is no chin
on the massive Jaw.
The brain capacity (of Neanderthal man) was 1550 ml. whloh
is as large as or larger than the cranial capacity of modern
races, but it was due to increased capacity at the back of
the skull rather than in the fore part as in modern man.
^

b3$
274.
275.
276.
277.
278.
279.
280.
281.
282.
285.
284.
285.

286.
287.
288.
289.
290.

291.
292.
293.
294.
295.
296..
297.
298.

(Neanderthal) males were about 5 feet 4 Inches tall and
females about 4 feet 0 Inches tall.
The posture via8
stooped and the knees slightly bent.
Neanderthal man used flint tools.
Cro-Magnon man was first found in the Cro-Magnon vdcinity
of Franoe.
(Cro-Magnon man)is bfelleved to represent a race of man that
replaced the Neanderthal type in Europe.
(Cro-Magnon man) was essentially modern.
The head was large
with no brow ridges, a high forehead, a prominent and narrow
nose, and a well developed chin.
The cranial capacity (of Cro-Magnon
man) was 1700 to 1800 ml.
The Cro-Magnon males were 6 feet or more in height.
The CrorMagnon people disappeared at the end of the Plelstooene period and were replaced by modern man.
There is evidence that some of the people living in North
Africa, Canary Islands, Iceland, North Germany, and Norway
. may be descendants of the Cro-Magnon man.
Modern man evolved during the late Pleistocene and became
sub-divided into several racial types or sub-species.
The major races are the Negroids, the Mongoloids and the
Causa8olds.
(While) most human beings fit into one or the other of these
categories (Negroid, Mongoloid or Caucasoid), there are
many intermediate types and It is probable that at present
there is no such thing as a pure race.
Man has always been nomadic, with the result that no human
group has remained isolated long enough to prevent inter­
breeding with other races.
The Negroid race includes the dark-skinned people who have
curly hair and long heads.
The Mongoloids are the yellow and the red-skinned people
of the world.
They have broad heads and straight hair.
Indians, Chinese, Japanese, Malays and Eskimos ere Mongoloids,
The Cauoasold race or Caucasians are usually white-skinned,
though they also habe.some pigment in their skin.
Their
head shape may be long or broad and their hair form is gen­
erally wavy.
Early in the history of Ilf e. the stream of evolution divided
into two branches, the animals and plants
The separation of living things into two kinds ocoured while
life was still in its simple cellular stage.
The first plants were probably single cells that differed
from their animal relatives by having chlorophyll.
The early plants lived in water.
Many of the descendants of the early plants, the thallophytes,
still remain (living in water).
Come of the thallophytes (descendants of the early plants)
have developed into large, complex, roany-celled structures,
though many are still single-celled.
During the time (Devonian) when the lobe-finned fish were
eilmblng out on land to, evolve into the amphibians, plants
were also moving out of water.
(In fact), it is very probable that the plants preceded the
animals on land, for the animals could not have remained there
had there been no food available.
^

299.
300.
301.
302.

303.
304.
305.
306.
307.
308.
309.
310.
311.
312.

313.
314.
315.
316.

317.

318.

Some at the most prominent and successful of these early land
forme were the seed ferns.
(Early seed ferns) grew to the size of modern trees, some of
them having stems three feet in diameter.
(Early seed ferns) differed from modern ferns not only in
size but also in producing seeds.
Modern ferns! do not produoe seeds.
The seed ferns and their relatives, such as the tree-like
horsetails and club mosses, flourished in wet, swampy ground.
Many of them were preserved after death and changed through
compression within the earth tolbrm coal.
The gymnosperms, represented today by the evergreen, evolved
after the ferns.
(The early gymnosperms) had strapllke leaves rather than the
needle-shaped leaves present in modern forms (of gymnosperms).
The true flowering plants appeared later, about the middle
of the Mesozolo.
(The true flowering plants) were very successful land plants
and spread over the entire earth.
Today they (flowering plants) are the dominant land plants,
though representatives of other forme still exist,
The most direct evldenoe that all living things have developed
by evolution is the evldenoe of fossils.
Fossils are the remains of animals and plants that lived
during the past ages.
(Fossils) may be foot prints, animal burrows, leaf prints or
any sort of indications of past life.
It Is possible to determine the approximate time when fossil
forms lived and also to determine the sequence of their ap­
pearance on earth.
From the study of sequenoe (of fossils) it becomes readily
apparant that the simpler forms of life appeared first and
that more complex forms followed, to be followed in turn
by organisms still more complex.
The order of appearance of animal forms is first the simpler
Invertebrates, then the more complex invertebrates.
The complex .Invertebrates were followed by the primitive
vertebrates, the ostraooderms.
(Following the appearnce of the ostracoderms) the fish then
evolved and the amphibians oame later, to be followed by the
reptiles, birds and mammals.
Many of the forms that lived In the past are no longer pre­
sent.
*t Is true that representatives of all great animal
groups o a n b e found on the earth today, but countless forms
related to eaoh of the forms how living have ceased to exist.
Each major group evolved in its turn and produced a myriad
of forms whloh spread over the earth into every available
habitat.
Then eaoh group declined, leaving a few hardy mem­
bers to oontinue the struggle for existence, but never again
to fluorlsh and to dominate the earth.
£a eaoh group deollned In numbers and types, a new group
would appear.
It (the new group) would produce millions of
individuals and many new forms and then it, too, would event­
ually decline.

h37
319.
320.

321.

322.

323.
324.
326.

326.
327.

(Finally), the mammals appeared and today maa, as a repre­
sentative of this group of animals, dominates the living soene
All other evldenoeTbesides that based on the fossil record)
that supports the principle of evolution Is based on one
fundamental assumption.
It Is that similarity of organisms
Indicates relationship and that the degree of closeness of
similarity runs essentially parallel to the closeness of
kinship.
The Validity of this assumption (that similarity of organisms
indicates relationship) is apparant when it is considered
in relation to human k&nshlp,
It is well known that some
Identical twins are so alike that their friends and even their
families have difficulty in distinguishing between them.
This
likeness Is due to their common heredity.
Identical twins
have the same kinds of genes because they develop from the
same fertilized egg.
Thus both likeness and relationship
are as olose as they can possibly be in any two living organ­
isms.
The next most closely related humans are offspring, not
identical twins, of the same parents.
These are known as
siblings.
They are less alike than Identical twins and also
their relationship is not quite so close because they develop
from different zygotes.
They receive many of the same kinds
of genes but also many different kinds of genes.
Cousins represent a human relationship that is still
farthur removed from the identical twins.
Their relation­
ship Is not so close as between either identical twins or
siblings because their oommon ancestors are grandparents.
They have fewer like genes in common, and they also have fewer
characteristics in common.
Individuals of the same race have many characteristics in
oommon, hence must have a oommon heredity from a common an­
cestor, but the ancestor lived many generations ago and the
similarities are fewer than those found in cousins and sibling!
On the basis of the assumption that similarity cf structure
indicates relationship due to inheritance from a oommon an­
cestor the entire system of classification is a genealogy of
living forms.
All individuals belonging to a species are alike, and being
related, they all have a common ancestor.
(Likewise), all speoies that are alike are related.
This relationship (between speoies) is indicated in the
system of classification by placing similar species in one
genus.
Hence, the animals or plants belonging to a genus
are related*
Genera that are alike are grouped into families
and like families into orders.
Like orders are grouped into
classes and olasses into phyla.
Finally all animal phyla
are grouped on the basis of similarities into the animal king­
dom and all plants into the plant kingdom.
Evan the plants and animals have some ohara c tdr I sties in
oommon, suoh as cells and protoplasm, so that they too show
relationships.
.
.
The logioal conclusion (based on the genealogy of living forms;
is that all living things are related.

h38
328.
329.
330.
331.
332.

333.

t1

334.
336.
336.

337.
338.

339.

340.

341.

Some (living forms) are more distantly related th*n others,
hut the evldenoe of a oommon ancestor Is to be seen even In
the most dissimilar of forms.
If this relationship (among living organisms) is accepted It
follows that evolution must have occured; for if no change
had taken place all living things would be alike.
Evldenoe from the study of comparative anatony supports the
theory that animals are basloally alike and honce related even
though they differ In superficial appearance.
In some organisms the similarities are obscured by modifications
of organa as a result of adaptations to the environment.
(An example in whloh similarities are obscured as a result of
adaptation can be seen in) the skeletal structure of the arm
of man, the foreleg of a horse, the flipper of a. whale, the
wing of a bat and the wing- of a bird. All are fundamentally
the same but in each form the bones have become modified In
relation to the particular function that eaoh performs,
Structures that have a basic similarity but which have develop- ’
ed special functional adaptations are said to be homologus,
The study of embryology also contributes evidence of the
fundamental similarity of animals.
During the embryonic development of animals similarities ap­
pear that would neyer be suspected on the basis .of a com­
parison of adults.
Animals that differ only slightly as adults such as the dog
and wolfi or man and ape are so similar during the early stages
of development that It Is Impossible to tell them apart. They
look exactly alike.
During the lAter stages of development
the dlfferenoes that are vlsable In the adult begin to appear.
Animals that are widely different as adults are more easily
distinguished as embryos, but some similarities remain in the
early stages.
For example (of similarities In the embryo) all animals begin
development as a single oell, the zygote. Ail animals above
the Protozoa go through a period of oell division which ends
In the formation of a two layered gastrula. All animals from
the flatworms up go through another common stage, which Is
the formation of the third layer of cells, the mesoderm.
Another very striking example of related out different organ­
isms going through similar embryonic stAges Is that of the
development of gill slits in the embryos of all vertebrates.
In fish the gill slits appear in the embryo and remain In
the adult as funotlonal structures, but in amphibia, reptiles,
birds and mammals they appear for a short time only during
development and then disappear before birth.
The appearance of (these) gill slits In embryos Indicates
a genic complex oausing their development.
The only possible
explanation Of the presenoe of these genes in all vertebrate
embryos Is oommon ancestory;
On the basis of similarities JMund among all animals during
embryonic development a theory has been proposed which states
that during embryonic development every animal goes through
developmental states that correspond to evolutionary stages
which the anoestors of the animal have paseed through. This is
the Theory of Recapitulation.

U39
342.

243.

244.
242.
246.
247.
348.
349.

350.
351.
352.
353.
354.
355.
356.

An example to Illustrate the theory of Recapitulation follows:
The human embryo starts as a single cell, the zygote.
This
zygote supposedly represents the single oell stage of evolution
that oooured at the vefiy beginning of life on earth.
The
next embryonlo stage Is oell division of the zygote Into a
"hollow ball of cells" stage oalled the biastula, whloh sup­
posedly corresponds to the time in evolution when colonial
Protozoa represented the highest development of Ilf©.
In the
following divisions of the zygote the embryo becomes a twolayered blastula, which corresponds to the two-layered animal
stage represented in modern forms by the coelenterates. The
next major embryonlo step is the formation of mesoderm whloh
presumably followed the evolutionary development of threelayered forms.
The flatworms of today represent this evolution­
ary step.
The appearanoe of gill slits in human embryos re­
presents the fish stage of human evolution.
(Thus), it Is possible to relate most of the stages of em­
bryonic development with a corresponding stage in evolution
and also with a modern animal type that apparently stopped
its evolutionary developmeht at one or another of the evol­
utionary steps.
The validity of thld :theory (of Recapitulation) Is questioned,
particularly In relation to Its extension to include all
embryonlo stages and structures In an evolutionary sequence.
Obviously no. animal can go through Its entire evolutionary
history in the short time It takes for embryonic development.
Many stages (in embryonic development) are telescoped and
many more are left out entirely.
(Furthermore), many embryos have developed special structures
that have no evolutionary significance beyond the aid they
ive the embryo in survival,
Consequently), It is impossible to read the entire evolution­
ary history of an animal In its embryonic development.
(Nevertheless), it Is probable that the embryo does repeat
a few of the evolutionary stages of Its ancestors, and In so
far as It is possible to recognize these, the Theory of Recap­
itulation Is valid.
All animals including man have certain vestigial anatomical
structures that hare no apparent use.
The appendix in man is such a(vestigial anatomical)structure.
The degenerate muscles by. means of whloh a certain few human
beings can wiggle their ears Is another(example of a vestigial
structure).
The ooooyx or tall bones of the human skeleton represents
another example of vestigial structures.
By comparing (the) structure (of vestigial organs) with
similar organs in related forms It becomes apparent that they
are vestiges or remnants of fully developed useful organs.
(For example), the human ooooyx Is a remnant that represents
the tall vertebrae of other primates.
The development of the ooooyx in any individual Is due to
genes whloh oome from its ancestors.

f

Mo
3576
358.

(Presumably, therefore) man’s ancestors h a d g o n e n causing
the development of a tall whloh In modern forme have been
reduced in their effect so that a remnant only develops.
No other explanation (except a genetic one) is logical on
the basis of out knowledge of Inheritance.

p r i n c i p l e : ii

The evolution of living things is, in the broadest sense,
progressive and not regressive in nature.
1.
2.

3.

4.
5.
6.
7.
8.
9.
10.
11.
12.
13.

Evolution seems to be progressive.
Within the total picture, the evolution of individual forms
tells the same story. For example, the horse began as a small,
five-toed creature that evolved in a more or less direct line
into & large, single-toed animal.
The loss cf toes Tin the horse) was not sudden but gradual.
During the millions of years that elapsed while the horse was
evolving, some of the toes beoame gradually reduced in else and
were lost, while one on each foot increased in size.
Other fossil animals and plants show this same progressive change
(that the horse shows) by steps from one condition to another.
One explanation of this progressive evolution is orthogenesis,
whloh olalms that there is some unknown force within the organ­
ism that guides its evolution.
Another explanation of progressive evolution is natural selection
The Theory of Natural Selection was proposed by Darwin.
According to the Theory of Natural Selection all organisms are .
engaged in a struggle for existence.
Each generation produces many more offspring than can possibly
survive primarily because of limited food supply.
The offspring vary in their ability to compete for the available
food and consequently during this competition some perish.
The offspring that perish in the struggle for existence are the
less fit, those that survive are the most fit.
(Thus) Natural Selection results in the survival of the fittest.
The survivors (at any given time) then overproduce another gener­
ation and the competition and seleotion goes on.

PRINCIPLE III
(terminal variation is essential to the continuance of evolution.
1.

2.
3.
4.

5.

In order that evolution can occur, it is necessary that different
kinds of organisms be prdduoed.
One source of new organisms is sexual reproduction.
Each generation of offspring of sexual parents differs in some
respects from the preceding generation.
(Offspring of sexual parents differs from the preceding gen­
eration) due to the uniting of half of the genes from each
parent in fertilisation with the result that an organism some­
what different from the parents is produced..
It is known that aocording to the laws of heredity the degree
of variation in organisms is limited.

llij!
69
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.

18.
19.
20.
21.

22.
23.
24.
25.
26.

(The) source of new organisms is limited because the number
of different genes that can combine is limitedo
Something besides sexual recombination of geneo is necessary
before evolution can continue indefinitely.
Some ohange in heredity must have occured to produce the
millions of different living things that have inhabited or
still inhabit the earth.
The additional neoessary factor (additional to sexual re<oomblnatlon if evolution is to continue) ismutation.
This ohange in heredity is the essenoe of evolution.
There are different kinds of mutations, all of which Involve
a ohange in the meohanlsm of heredity, but the most fundamental
is gene mutation.
Gene mutation is a change in a gene that results in the develop­
ment of a new inherited trait.
It is believed at the present time that (gene mutation) is the
source of all variations that result in evolution.
Xears ago a Frenchman named Larnaroh suggested that changes in
the meohanlsm of heredity were brought about by the use or
disuse Of organs or parts of the body.
This (theory of Lamarck's) is known as the Theory of the
Inheritance of Aoqulred Characters.
According to this theory (of Lamarck) the loss of toes that
oooured during the evolution of the horse resulted from the
laok of use of suoh toes.
How the use of an organ apparently resulted in its change can
be illustrated by the long neck of the giraffe.
It was supposed
that the giraffe got its long neck by stretching upward in
search of food In tall trees.
This theory (of Lamarck) was very attractive because it explained
so simply how animals and plants became adapted to their environ­
ments.
(According to Lamarok’s explanation) many cave dwelling animals
are blind because they did not use their eyes in the dark
caverns.
Likewise (aooordlng to Lamarok), the whale became streamlined
and developed fllppera and a fish-like tall by living in the
water where suoh body traits are useful.
As attractive as (the Theory of the Inheritance ofAoqulred
Characters) is, it is probably not true, because we do not in-r
herit characteristics of the body that are developed as a re*suit of the direct effect of the environment.
We inherit but one thing and that is a complex of genes that
is contained in the germ cells.
Changes in the body suoh as the enlargement of muscle through
exercise or the skill and coordination that results from long
practice do not affect the genes in the germ cells.
One can listen for a lifetime to good music and can practice
day after day on a musloal instrument and One's offspring will
be no more musloal than the genes will allow.
Changes within the genes contained in the germoells oan be
caused by a number of different things.
In one kind of plant it was found that aging of the seed would
induce mutations.

bte
27.
2Q.
29.
30.

31.
32.
33.
34.
35.
36.
37.

In the fruit fly high temperatures wil l cause mutations.
Most important of all environmental factors O.n relationship
to mutations) is Irradiation by x-rays.
Earth radiation and cosmic rays also cause genes to change.
After the discovery that irradiation caused gene mutation, it
was thought that the naturally occuring rays that come from
the earth and from space would be sufficient to account for
all of the mutations that occur spontaneously In animals and
plants.
(But) it was found that many more mutations occur than could
be accounted for on the basis of the amount of irradiation
present.
Something else (other than naturally occuring rays), still
unknown, causes the bulk of the mutations.
Nobody knows what the unknown factor is that causes the bulk
of mutations.
Natural selection results in the survival of the fittest (of
the mutants).
If one thinks of survival in terms of genes, it becomes
obvious that the genes possessed by the survivors are the
cnee that are passed on the the next generation.
The genes of the individuals that perish are lost and no not
contribute to the evolution of the population.
Add to this (concept of the survival of genes), the factors
of Isolation and mutation and it becomes evident how two
or more different kinds of organisms can descend from a single
oommon ancestor.

PRINCIPLE IV
The interaction of organisms with their environment results
in a natural selection of certain organisms.
The ultimate
consequence of this selection is the origin of new species.
1.
2.
3.
4.
5.
6.
7.
8.
9.

According to the Theory of Natural Selection all organisms
are engaged in a struggle for exlstenoe.
Eaoh generation produces many more offspring than can possibly
survive primarily because of limited food supply.
The offspring vary In their ability to compete for the avail­
able food and consequently during this competition some perish,
The offspring that perish in the struggle for existence are
the less fit, those that survive are the more fit.
(Thus) Natural Selection results in the survival of the fittest,
The survivors (at any given time) then overproduce another
generation and the competition and selection goes on.
If one thinks of survival in terms of genes, it becomes obvious
that the genes possessed by the survivors are the ones that
are passed on to the next generation.
The genes of the individuals that perish are lost and do not
contribute to the evolution of the population.
Add to this (concept of survival of genes) the factors of
isolation and mutation and it becomes evident that two or
more different kinds of organisms can descend from a single
common ancestor.

kk3
10.
11.
12.
IS.

14.
15.
16.
17.
16.
19.

Isolation means the separation of individuals of the same
kind from each other so they cannot mate.
Isolation may result from migration whore one group wanders
off into new territory.
Isolation may result from physical changes in Individuals
within a single area so that such individuals cannot mate.
An example (of physical ohange of individuals within a single
area preventing mating) is the ohange that oooured in the
oopulatory organs of a type of fruit fly that prevented other
flies from mating with it.
Social custom suoh as race prejudice that discourages Inter­
racial mating in human sooletles may result in a kind of
isolation.
What ever the cause of isolation if two groups of organisms
of the same kind are separated from each other they will
evolve separately.
(When two groups of organisms of the same kind are separated)
new mutations will occur in eaoh group.
New genes (arising in separated groups) will be confined to
the group in which they arose because there is no mating
with other groups.
The result (in Isolated groups) will be independent mutation
and selection in eaoh group and hence independent evolution.
If the environment of two Isolated groups is the same the
evolution may be parallel, but if it differs it is likely
that the two lines of evolution will be different.