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This is to certify that the

thesis entitled

Teaching the Structure and Function
of Plants to Seventh Grade Students

presented by

Jodie L. Fisher

has been accepted towards fulfillment
of the requirements for

Masters Biological Science

degree in

 

 

Major professor

Date July 11, 1996

 

0-7 639 MS U i: an Affirmative Action/Equal Opportunity Institution

 

PLACE Ii RETURN BOX to mow this checked tram your record.
TO AVOID FINES return on or before date duo.

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TEACHINGrTHE STRUCTURE.AND FUNCTION OF
PLANTS TO SEVENTH GRADE STUDENTS

By
Jodie L. Fisher

A.THESIS
Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

BIOLOGICAL SCIENCE

Division of Science Education

1996

 

 

 

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ABSTRACT

TEACHING THE STRUCTURE AND FUNCTION OF
PLANTS TO SEVENTH GRADE STUDENTS

By
Jodie L. Fisher

The topic of my thesis is using the constructivist ap-
proach to teach the structure and function of plants to
seventh grade students. I included a combination of various
teaching and learning strategies with a focus on "hands-on"
activities. Students conducted laboratory investigations
that I developed at Michigan State University in 1995. They
made concept maps, wrote in journals, and dissected flowers
as part of this unit. I used a focus group consisting of 2
higher-level students, 2 middle-level students, and 2 lower-
1eve1 students for purposes of evaluation. These students
all showed significant improvement in their understanding of
the structure and function of plants after the teaching of

this unit.

ACKNOWLEDGMENTS

I would like to thank Dr. Merle Heidemann for her
patience and understanding as I struggled with my thesis this
past year, Dr. Kenneth Nadler for sharing his expertise on
plants with me and giving me great lab ideas, and Dr. Joyce
Parker for imparting her vast knowledge of alternative

assessment ideas.

 

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DIS

 

 

TABLE OF CONTENTS

INTRODUCTION................................................1
Statement of Problem and Rational for Study............1
Demographics of the Classroom..........................4
Literature Review'of Scientific Principles.............5

Classification....................................6
Life Cycle........................................7
Photosynthesis....................................8
Food.Storage.....................................11
Transpiration....................................11
Respiration......................................12
Literature Review'of Teaching.Approach................14

IMPLEMENTATION OF UNIT.....................................20
Basic Outline.........................................20
Daily'Calendar...................................20
Audio-VisualwAids.....................................29
neereaching’Techniques...............................30
Laboratory’Investigations.............................33

EVALUATION.................................................45
Pre and.Post Tests....................................45
Analysis........................................52
neereaching'Strategies..............................55
Student,Interviews...................................56
Subjective Evidence-Informal Discussions.............60

DISCUSSIONANDCONCLUSIONS................................63
Aspects of New ”Hands-On" Materials in Unit
Particularly Effective in Conveying Key
Information..........................................63
.Analysis of What was Effective.......................65
Aspects of the Unit that need Improvement............66
Overall Evaluation.and.Conclusion....................67

APPENDICES
Appendix.A
Objectives.....................................68
Appendix B
CompleteILaboratory“Write-ups..................70

Appendix C
Sample Student Concept.Maps...................103

Appendix D
Instructor's concept HaPOOOIOOOOOOOOO0.0.0.0...117

Appendix E
Central.Question............... ...... ..........121

 

 

In

I NTRODUCT I ON

The topic of my thesis is using the constructivist
approach to teach the structure and function of plants to

seventh grade students.

A. STATIINT OP PROBLEM AND NATIONAL-E FOR STUDY

The goal of my thesis was to choose a unit from the
MEGOSE (Michigan Essential Goals and Objectives, 1992) and
teach this unit using the constructivist approach to teaching
and learning. I chose to teach.a plant unit to seventh grade
students. The central question I posed to students was: How
are plants, as producers, fundamentally different, yet
similar to consumers such as humans and other animals? (See
Appendix.E)

I chose this problem.as a basis for my thesis because
St. Johns School District recently rewrote our Science
curriculum.to align it with the MEGOSE. Our K-12 teachers
met to decide which grade level was going to teach which
topics. .As a result of this meeting, we are to teach 6 units
at the seventh grade level instead of 13. These six units
are: the solar system, ecology, ecosystems, classification,
cells, and plants. I chose plants for my thesis topic because
I felt it was the unit that lacked hands-on activities and

laboratory investigations, resulting in low student test

 

 

 

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scores (both on the final exams and the unit test). Also, it
was the one which I, as the instructor, understood the least.
As is every teacher's goal, I wanted my students to better
understand the concepts of plant biology. Teaching fewer
units allowed me to teach six to nine week units instead of
the two weeks I previously spent. Obviously, this allowed me
to»do:mcre laboratory investigations and hands-on activities
with my students .

In the old schedule, we began by defining the vocabulary
terms found at the end of every unit (Prentice Hall, 1991).
we would read the three or four sections in the book that
comprised the unit, I would teach one of the following four
note-taking strategies: outlining, concept mapping,
highlighting, and two-column notes for the students to use as
they read the chapter. At the end of every chapter there was
a chapter review, consisting of questions in.multiple choice,
completion, true/false, skill building (short answer), and
essay formats. There always was one lab included in the
chapter. If time permitted, we would include this
investigation.

The instruction in our previous schedule, was very
teacher-centered. Students were given very little
opportunity for discussion or exploration, Besides the essay
questions, no higher level thinking or problemssolving skills
were used by the students. It was simply a matter of rote

memory or having good reading skills.

 

 

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The new approach was vastly different. I included a
combination of various teaching and learning strategies .
Using the constructivist approach, in which students
construct their own knowledge, there must be a connectedness
between students ' own prior knowledge, objects and phenomena
in the real world, and other scientific ideas (Smith, 1990) .
For this to happen, students must be dissatisfied with their
current conceptions (begin to question their conception) and
be provided with an intelligible alternative (one that makes
sense to them). The alternative must be plausible
(believable) and fruitful (produce better results than their
prior conception). In order for these things to happen, my
teaching style had to change because it did not encompass
these aspects .

I began by finding out what students already knew. This
was accomplished in a variety of ways. Pre-tests were given,
brainstorming lists were made, clinical interviews were done,
and journal writing was required as a means to find out what
they did or didn't know. Often times student dissatisfaction
came with simply hearing other students ideas that were
different than their own, observing a discrepant event, or
posing a question or laboratory that could not be solved with
their knowledge.

Again, alternative ideas came from other students'
suggestions or laboratory investigations that lead them to
actually “see" that their predictions were not correct.

Students had to actually "try it" for themselves to believe

 

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that the alternative really worked and it had to fit with

what they already knew of the world. They had to relate it to
"axioms" (things they, and everybody else, know'to be true)
and find that it did, indeed, make sense (it fit with what
they knew, and was more feasible than their prior
misconception).

In order for constructivism to work and be successful,
it was necessary for me to make my classroom and instruction
more student-centered, I extracted laboratory investigations,
activities, and background information from a variety of
materials. Much of my own background information
came from the book "Biology of Plants", fourth edition, by
Peter H. Raven, Ray F. Evert, and Susan E. Eichorn; WOrth
Publishers Inc., 1986. This is a college book for Botany
non-majors. It is written so that non-majors can understand
the content, but goes beyond a simple perusal.

The laboratory investigations were taken from my
classroom textbook, Prentice Hall, Merrill, "Focus on Life
Science", 1987, and the ”Fast Plants" manual. I used the
SEMSplus Module? Unit planning for conceptual change by
Berkheimer, Anderson, and Smith as a basis for the design of

the unit.

B. DEMOGRAPHICS OF THE CLASSROOM

The class I chose for study in this unit, was my seventh

grade class. The class consisted of 26 students: 5 girls and

5
21 boys chosen randomly by computer. I have 8 special

education students in this class, therfore, I co-teach with a
special education teacher. I decided to focus on 2 higher-
level students, 2 middle-level students, and 2 lower-level
students for purposes of evaluation. .As the lower-level
students I chose two special education students.

I determined which students I would use by a random
draw. I determined which of the 26 students belonged in the
category of high, medium, or low levels, I based this on
students' MEAP (Michigan Educational Assessment Performance)
scores and I discussions with their sixth grade science
teachers. I then put them.into a hat and simply drew 2 high,
2 medium, and 2 low level students as my sample group for

evaluation.

C. LITERATURE REVIEW 01" SCIENTIFIC PRINCIPLES

The scientific concepts explained and.demonstrated in
thisunit are: (1) the classification.of organisms into
major groups on the basis of their structure; (2) the life
cycle of a flowering plant; (3) evidence that plants make
and store food; and (4) how selected systems and processes
work.together in plants. Background information on each of

these four objectives is presented below.

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Aristotle was the first to try to classify organisms.
Be classified organisms on how they moved. This method of
classification was inexact because sometimes their method
of movement was the only characteristic they had in
common. John Ray tried to classify organisms according to
their internal anatomy. This was also inexact because
organisms with similar internal anatomies were dissimilar
in most other respects. It was Carolus Linneaus who
developed the classification system used today. He
classified organisms according to similar characteristics.

In medieval times, Latin ”polynomials" were used to name
organisms . This five-word naming system was complicated and
tiresome. In 1753, Linneaus published a two-volume piece of
work, Spgies Plantarium. Instead of using the polynomial
designations , he laid the foundation for the binomial (two-
term) system of nomenclature. Linneaus wrote a single
word, which, combined with the generic name, formed a
convenient "shorthand" designation for the species .
Seventh grade students should be able to sort specific
plants into broad groupings such as flowering/non-
flowering, seed plants/non-seed plants, or
gymnosperms/angiosperms and be able to utilize the binomial
nomenclature naming system developed by Linneaus .

To understand that these plants belong in different

groupings, it is necessary for the students to know the

 

 

 

 

7
structure of these organisms. Understanding the life cycle

of a flowering plant and the parts of a flowering plant
‘will allow them to look for these characteristics in a new

plant and classify it.

LI PE CYCLE

To understand the life cycle of a flowering plant
students will observe the growth of Wisconsin Fast Plants,
Brassica raga. Brassica rapa completes its life cycle,
from.seed to seed, in 35-40 days.

Through various experiments, students will realize that
germination is dependent on environmental conditions. The
proper moisture, temperature, and oxygen levels must be
present for germination to take place. The maturity of the
seed at harvest and seed dormancy also affect germination.

.After germination, seeds go through a stage of
vegetative growth where they develop roots, stems, and
leaves that grow rapidly. The seedling, at this stage, is
still sexually immature. Then the immature plant begins to
develop flower buds.

The development of flower buds leads to a process known
as gametogenesis: the production of the reproductive cells.
The mature plant contains flowers which effect pollination.
Pollination, which requires, in the case of the Brassica
papa, pollinators such as insects, is the first stage in
the reproductive cycle. Here, the pollen from.the anther of

one plant is transferred to the stigma of another plant

8

(in the case of cross-pollination). The pollen tube
travels down the style to the ovary where it unites with
the female's egg. The uniting of the pollen and the egg is
the process of fertilization. Fertilization is the second
stage in the reproductive cycle of the Brassica raga.

Once fertilization is completed, a mature parent plant
produces an embryo. This process is known as
embryogenesis, when the growth and development of the
endosperm and embryo occurs. Eventually, the seed becomes
independent of its parent and this step is the death of the
parent Fast plant. With the death of the parent plant, the
seeds that are independent of the parent but are dependent

on the pod and the environment for dispersal.

PNOTOSINTEES I S

Students have difficulty grasping the idea that plants
make their own food. Students still believe plants must, in
part, get their food from the soil. They are not alone in
their'beliefs.

Until a little over 300 years ago, there were many
scientists who also believed this to be true. The Belgian
physician Jan Baptista van Belmont, discovered that soil
alone does not nourish the plant. He grew a small willow
tree in an earthenware pot, adding only water to the pot.
At the end of five years the willow had increased in weight

by 74.4 kilograms. ‘Whereas the earth had only decreased in

9

weight by 57 grams. Therefore, van Belmont incorrectly
concluded that all the substance of the plant was produced
by from.the water and none from.the soil or the air.

Toward the end of the eighteenth century, the English
scientist Joseph Priestly reported that he had
”accidentally hit upon a method of restoring air that had
been injured by the burning of candles”. On August 17,
1771, Priestly "put a [living] sprig of mint into air in
which a wax candle had burned out and found that, on the
27th of the same month, another candle could be burned in
the same air". Priestly's experiment showed that plants
take up the C02 produced by combustion or exhaled by
animals, and that plants do produce oxygen.

The Dutch.physician Jan Ingenhousz confirmed Priestly's
work and showed that the air was restored only in the
presence of sunlight and only by the green parts of plants.
In 1976, Ingenhousz went a step further and suggested the
following equation for photosynthesis

C02 + 320 + Light Energy = (CHZO) + 02
assuming that the carbohydrate came from.a combination of
the carbon and water molecules and that the oxygen was
released from the carbon dioxide molecule. This
hypothesis, as it turned out, was wrong.

C.B. van Niel of Stanford University refuted this
theory. Using purple sulfur bacteria, a photosynthetic
bacteria, he proposed that water, not carbon dioxide, was

split.in photosynthesis.

10
In 1905, plant physiologist F. F. Blackman, discovered

evidence that photosynthesis is a two stage process. He
proposed that there was one set of light-dependent
reactions that were temperature independent. In this '
reaction, light energy is used to form ATP from ADP and to
reduce electron carrier molecules. He also suggested a
second set of reactions that were dependent, not on light,
but on temperature. In this reaction, energy products of
the first stage are used to reduce carbon from.aarbon
dioxide to a simple sugar. He realized that when both
factors (temperature and light) were increased the rate of
photosynthesis was greatly accelerated. Therefore, he
concluded that both sets of reactions were required for the
process of photosynthesis.

It is fromtthis combination of initial discoveries that
the modern understanding of photosynthesis comes: the
process where light energy is converted to chemical energy
(with the help of chlorophyll and other photopigments and
enzymes found in chloroplasts), and carbon is "fixed" into
organic compounds. This is expressed in the following
equation.

sunlight+ 6C02 + GEZO = cealzos + 602

(energy) (carbon dioxide) (water) (glucose) (oxygen)

 

 

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Food storage in plants can take place in stems, roots,
leaves, and seeds. Food is usually found stored in plants
as starch or polysaccharides. Foods manufactured above
ground in photosynthesizing portions, primarily leaves, or
the plant body, move through the phloem to the storage
tissues. This food may eventually be broken down and
transported back through the phloem.to tissues requiring
energy.

An example of food storage in the stem.is the tuber,
exemplified by potatoes. Tubers can be found at the ends of
long, thin rhizomes (underground, horizontal stems) or the
tips of stolons (slender stems growing along the surface of
the ground). Other examples of food storage in the stem
are bulbs such as onions and corms such as gladiolus.

In seeds, food storage occurs in the cotyledons and
endosperm, In gymnosperms, the stored food is provided by
the haploid female gametophyte. In angiosperme, it is

provided by triploid.endosperm.tissue.

TRANSPIRATION

Transpiration is a good example of how selected systems
and processes work together in plants. Transpiration is
the loss of water vapor by any part of the plant body,

although leaves are by far the principal organs of

12

transpiration. water vapor is lost through the stomata in
the leaves.

How are transpiration and photosynthesis linked? The
necessary energy for photosynthesis comes from sunlight.
Therefore, for maximum.photosynthesis, a plant must spread
a.maximum.surface to the sunlight. Chloroplasts not only
need sunlight, but they require carbon dioxide. In order
for the carbon dioxide to diffuse into the plant cell, the
gas must come into contact with.a moist cell surface.
However, wherever water is exposed to air, evaporation
occurs. Plants have developed adaptations to limit
evaporation, but all of these out down the supply of carbon
dioxide. The uptake of carbon dioxide for photosynthesis
and the loss of water by transpiration are inextricably

bound‘together.

RESPIRATION

Respiration is another good example of how selected
systems and processes work together in plants. A
relationship’exists between respiration and photosynthesis.
In the course of photosynthesis, the energy of the sun is
used to forge high-energy carbon-carbon and.carbon-hydrogen
bonds; then, in the course of respiration, these bonds are
broken down to carbon dioxide and water, releasing energy.

Respiration is the means by which the energy potential

of carbohydrates is used to make ATP-the universal energy

13
carrier. ATP is thus made available for the immediate

energy requirements of the cell. Respiration oxidizes
glucose, the building blocks of sucrose and starch. The

equation for the complete oxidation of glucose is as

follows
C6H1206 + 602 = 6C02 + 320 + Energy
(sugar) (oxygen) (carbon (water)

dioxide)

Respiration involves three stages.

(1) Glycolysis- the 6 carbon glucose molecule
molecule is broken down to a pair of 3 carbon

molecules of pyruvic acid or pyruvate.

(2) The Krebs Cycle- The Acetyl group, derived from
pyruvate, is broken apart in a series of
reactions to yield carbon dioxide. In the
course of the oxidation of each acetyl group, 4
electron acceptors are reduced and another

molecule of ATP is formed.

(3) Oxidative Phosphorylation- The glucose
molecule is completely oxidized. Some of its
energy has been used to produce.HTP from ADP.

Most of it, however, still remains in the

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electrons removed from the carbon atoms as they
were oxidized. These electrons were passed to
the electron carriers NAD and FAD and are at a
high energy level. In the course of the
electron transport chain, they are passed
"downhill" to oxygen and the energy released is

used to form.ATP from.ADP.

D. LITERATURE REVIEW OF TEACHING APPROACH

The task of the teacher is to provide an environment
that is conducive for students to learn science with
understanding. This currently consists of providing a set of
stimuli and reinforcements that are likely to get students to
emit an appropriate response. If the goal is to get students
to replicate a certain behavior, this method works well; but
if our goals in education are understanding, synthesis,
eventual application, and the ability to use information in
new situations, a behaviorist approach is not successful.
Because there is no place in the model for understanding, it
is not surprising that behaviorist training rarely produces
it (Robert E. Yager, 1991).

In the past, this is the method of teaching I have
employed. My teaching consisted of having students define
the vocabulary words, read the chapter and take notes, and,
finally, complete the questions at the end of the chapter. I

would include a few experiments but I often failed to ask

 

 

 

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critical thinking questions. My questions usually focused on
what they saw, not why they saw it.

Constructivism, on the other hand, views students not as
the receptors for knowledge, but rather the prime actors in
constructing their own knowledge (Reilly, 1989) . Learning is
viewed as an active process that must occur within the
learner and that can be influenced by the learner (Weinstein
1985).

Learning outcomes do not entirely depend on what the
teacher presents. Rather, they are an interactive result of
what information is encountered and how the students process
it based on perceived notions and existing personal
knowledge. (Reilly, 1989).

Cognitive psychologists ' research on how children learn
challenges the assumption that teachers transmit knowledge to
learners . They argue that children discover and construct
meaning from their experiences in the environment through
analyzing data to detect patterns , forming and testing
hypotheses , and integrating new knowledge with previous
understandings. (Reilly, 1989).

From a Constructivist perspective, language must have
meaning. We use language to cope with our environment, to
help us make sense of our world, and to communicate how we
can use the meaning formulated. Von Glasserfeld says (Yager,
1991) , rather than presupposing that knowledge has to be a
representation of what exists, we should think of knowledge

as a mapping of what turns out to be feasible, given human

 

 

 

 

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experience. Teachers should also understand that knowledge
can not simply be transferred by means of words without first
having an agreement about meaning and some experiential
base.(Yager, 1991)

The Constructivist Learning Model of teaching cites two
criteria for understanding in science; connectedness and
usefulness in social contexts. The first criterion deals
with the structure of a persons' knowledge. .An idea is
understood to the extent that the learner has appropriately
represented it and connected it with other ideas,
particularly with the learners own prior knowledge and
beliefs. This is in sharp contrast to rote learning. A
concept is meaningful to the extent that it is non
arbitrarily related to other concepts in the individual's
cognitive structure (Smith, 1990)

The second criterion of constructivism, deals with the
function of a person's knowledge . .An idea is understood to
the extent that the learner can use that idea in successfully
performing significant tasks appropriate to the social
context in which they occur. Understanding is considered as
competent performance of tasks valued by the group in the
social context where they normally occur. Responsibility for
these tasks is gradually transferred to the learners until
they are able to carry out the tasks independently. (Smith,
1990)

Constructivists, then, propose that understanding a

scientific idea involves making connections between that

 

 

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17
concept and (1) the student's own prior knowledge, (2)

objects and phenomena in the everyday experiences, and (3)
other scientific ideas. This can be accomplished by
utilization of a "concept map" (Smith 1990).

Concept maps are intended to show connections or links
between scientific concepts, students' prior knowledge, and
their everyday experiences. I have previously used concept
maps in my classroom but I did not let students construct
them. I would give them a partially completed map and have
them finish it or I would simply do one for them and have
them copy it down. This method of concept mapping shows my
connections and uses my prior knowledge not the students ' .
They have not constructed their own knowledge . I have done it
for them. It is imperative that students devise their own
concept maps to truly see the connections they make between
prior knowledge, the concept, and everyday experiences .

Often, students ' prior knowledge is inconsistent with the
scientific knowledge that they are expected to learn. While
understanding requires relating new information to prior
knowledge, the prior knowledge must change (Smith, 1990) .
Students will not give up their beliefs easily. There are
some conditions that must exist before change can take place

(Smith, 1990) .

- Dissatisfaction with the prior conception must be
developed: they must find fault with their ideas;

- an intelligible alternative must be available;

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- The alternative must be viewed as plausible;
- The alternative must be viewed as fruitful: that is

more feasible than the prior conception.

Dissatisfaction can come from viewing a discrepant event,
posing a problem that, upon investigation, can not be
answered with the prior conception, or simply hearing peers
discuss a view different from your own. In order for
dissatisfaction to occur, the students mmst.question,
interact, and investigate.

An intelligible alternative, an alternative that makes
sense, must be available. I often let students come up with
their own alternative through laboratory investigations, or
in the case of plants, simple observations. ‘When an
alternative is found, we must discuss the feasibility of it.
Is the alternative plausible, is it believable, will it work
with what we know about plants and the world? In other words
can connections be made between what we know, everyday
experiences, and other scientific ideas.

The last, and often most difficult question is: is this
alternative fruitful, or more fruitful than the prior
conception? The last thing we want students to do is believe
the concept for the test but revert back to their mis-
conceptions once the unit is over. If the alternative fits
in their everyday experiences and makes sense they will want

to hold on to that belief.

19

In order for students to construct their own knowledge
and retain it, it was necessary for students to engage in
hands-on activities, laboratory investigations , model-making,
pre-testing, clinical interviews and other student-centered

activities .

 

 

 

 

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IMPLEMENTATION 01" UNIT

I developed a six-week unit on plants to be taught as
the first unit of the school year. The basic concepts of
this unit are: classification (angiosperms vs. gymnosperms),
the life cycle of a flowering plant, photosynthesis,
respiration, food storage, and transpiration. These
objectives were taken from the MEGOSE objectives under the
topic "Living Things". The following is a daily calendar of
events. In parentheses are the MEGOSE objectives they are
intended to meet (Appendix A). The calendar is based on

meeting everyday for 48 minute periods.

A. BASIC OUTLINE

DAILY CALENDAR

WEEK 1

MONDAY: Predict whether plants will grow'or live without
light, water, and carbon dioxide.(Ull&C1)
Predict whether plants will grow successfully under
various conditions (UlZ,C1,&C2)
Design a system.for plants to grow

successfully.(U14&C2)

20

ACTIVITY:

@2131;

ACTIVITY:

21

Pre-test
Introduction to Fast Plants

Plant Fast Plants seeds

Concept map(KWL)-What do we Rnow,‘What do we‘Want
to know, and what have we Learned about plants.
Why are specialized cells needed by plants and
animals?(U1)

What is the difference between a vascular and a
non-vascular plant? Explain how water and food

move through a plant.(U3)

Have students look at and describe a vascular and a
non-vascular*plant.

Look at cross sections of leaf cells, onion, celery
etc. and identify/draW'xylem.cells and phloem
cells.

DEMO-white carnation in food coloredawater.

WEDNESDAY:Describe the life cycle of a flowering plant.(U9)

ACTIVITY :

What is necessary for germination?

What occurs during germination?

Put Coleus plants (2) in dark

Set-up germination observation activity

Put together plant journals

w:

ACTIVITY:

FRIDAY:

ACTIVITY:

MONDAY:

22

Explain how a plant gets its food.(U5)

Explain why plants placed in the dark will
eventually'die.(U4)

Explain how a plant stores food.(U6)

Why is the presence of starch an indication that
photosynthesis is occurring? Why are light and C02
needed for photosynthesis?

What is the purpose of KOH?(U10)

What would happen if there were no plants?(C4&S)

Soak bean seeds
Record observations from germination activity in
plant journals.(C2&3)

Introduction to photosynthesis lab.(C2&3)

Plant bean seeds
Record observations from.germination activity in
plant journals.(C2&3)

Finish introduction to photosynthesis lab.(C2&3)

WEEK 2

Do the seeds appear to change in volume before they

split(See.Appendix.B-Germination lab)?

 

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It”

23
‘Why? What is the first structure to emerge from.the

seed?
‘When does chlorophyll first appear? What is the
function of the cotyledons? Did all the seeds
germinate? Why or why not?(U9)

ACTIVITY:
Record germination observations. Record number of
leaves and flowers on each plant. Measure and
record the height of the plant.(C2&3)

Complete germination lab questions.

TUESDAY: What are the parts of the plant? What are the male
and female reproductive organs/parts?(U9)
ACTIVITY:
Journal-sketch your plant and label the parts

dissect a fast plant and identify/draW'parts

WEDNESDAY:
ACTIVITY:
JOurnal observations

Plant.models

THURSDAY: Any new'plant parts?(U9)
ACTIVITY:
Prepare water for tomorrow's lab
JOurnal activities

Plant sketches

FRIDAY :

ACTIVITY :

MONDAY:

ACTIVITY :

24
Flower parts

Finish plant models

Describe evidence that plants make and store
food.(UlO)

What is a byproduct of photosynthesis? What raw
materials are necessary for photosynthesis to
occur? What is the role of sodium bicarbonate in
the Photosynthesis and Oxygen lab? In what cells
does photosynthesis occur? (U5&6)

design controlled plant experiments.(U13&C2)

Make bee sticks
Journal measurements (pay attention to internode
distances)

Photosynthesis and Oxygen Lab

WEEK 3

What is the function of the cuticle? The epidermis?
In what colors of light does photosynthesis occur

more rapidly? Why?(U5&13)

Pollinate Fast Plants
Journal.Activities

Finish Photosynthesis and Oxygen Lab

TUESDAY:

ACTIVITY:

25

Pollinate
Pinch off unopened buds
JOurnal activities-sketches

Photosynthesis and Carbon dioxide 1ab(C2&3)

WEDNESDAY:What are the parts of the flower? What are their

ACTIVITY:

THURSDAY:

ACTIVITY:

FRIDAY:

ACTIVITY:

functions?(UZ,3&9)

Journal activities
Jeopardy game

Finish photosynthesis and carbon dioxide lab

What evidence do you have that plants store

food?(U6&10)

JOurnal activities-sketches

starch tests in various conditions (dark vs.light)

How do seeds develop? What changes have occurred in
your plant? Why? Do plants continue to make new

leaves? New flowers? Do the parts lengthen?(U9)

‘Wrap corn seeds

Journal activities-sketches-length of pistil

26

Fertilization and seed.development activity

WEEK 4

MONDAY: Explain how'a plant converts food into energy and
waste materials. What occurs during respiration?
What is produced? How do you know? In what cells
does respiration.occur?(UZ,8&13)

ACTIVITY:
Respiration lab(C2&3)

Journal activities

M:

ACTIVITY:
Record.pistil lengths in journal-sketch plant
Journal activities(C3)
Finish respiration lab

WEDNESDAY:What is the interdependency of photosynthesis and
respiration?(U2,5,&8)

ACTIVITY:
What factors affect respiration lab(C2&3)

Journal activities

THURSDAY:
ACTIVITY:
Journal activities-record.pistil lengths-sketches

(Fast Plants)

27
Finish respiration lab

FRIDAY: Explain how a plant regulates water loss. What are
the effects of certain environmental conditions on
water loss?(U2,7&13)

ACTIVITY:

Transpiration lab(demo)

WEEK 5

MONDAY: Explain how a plant regulates water loss. What are
the effects of certain environmental conditions on
water loss?(UZ,7,&13)

ACTIVITY:
Finish transpiration lab (C2)

Journal activities

TILED—AI:
ACTIVITY :

Journal activities-pistil lengths-sketches

WEDNESDAY:
ACTIVITY:
Test'writing

Journal activities

THURSDAY :

ACTIVITY :

M:

ACTIVITY :

MONDAY :

ACTIVITY :

TUESDAY :

ACTIVITY :

28

Journal activities-record.pistil lengths—sketches

Finish transpiration lab

What are the size of the ovules? What do you see

inside the pod? Are some seeds in a pod more
developed that others? What do you see inside an

embryo? (Fast Plants) (U9)

Journal activities

Dissect the pod of Fast Plant

Prick an ovule and squeeze out developing embryo

WEEK 6

Remove Fast Plants from water

Journal activities

Journal activities

29
WEDNESDAY :

ACTIVITY :

Journal activities

THURSDAY: How many seeds in a pod? Any variations in the
seeds?
ACTIVITY:
Harvest seeds
Graph results(R1)
FRIDAY:
ACTIVITY:
Post-Test

Concept mapping
3. AUDIO-VISUAL AIDS

I used one audio-visual aid. It was a computer program
that showed how the processes of photosynthesis, respiration,
and transpiration related to the plant organs involved in
these processes. I did not have access to many audio-visual
aids. I did preview some, but I felt they were too advanced
for seventh grade. I also felt with the time that I had, six
weeks, I preferred not to use visual aids so that I had more

time for hands-on activities.

30
c. m Tucarnc neurons

In this unit, I used a combination of various teaching
and learning strategies including journal writing. I used
the constructivist teaching approach as a guide. I wanted
the students tolconstruct their own knowledge instead of me
trying to impart knowledge to them. Using the constructivist
approach, I attempted to make connections between students'
own prior knowledge, objects and phenomena in their everyday
experiences, and other scientific ideas.

I began by finding out what they already knew, This was
accomplished in a variety of ways. A Pre-test was given (see
Evaluation pg 39-part A). My pre-test consisted of the
following four questions: (1) What is food for plants?
Explain your answer. (2) Describe the life cycle of a
flowering plant. (3) Do plants breathe? Explain.your answer.
(4) If you were a plant what would your concerns be? I also
conducted clinical interviews with the six students I chose
as my core (See Demographics). I asked them the same four
questions as above but had students explain verbally to me
their thoughts and ideas. Another method of finding out what
students already knew'was simply to ask students what they
thought they already knew about plants. we then made a list
of all the things students thought they knew about plants
(see Evaluation pg 50-Part D). I had students write their
observations about the growth of their fast plants in

journals.

31

To convince students that there were alternatives to
the misconception they held, it was necessary to perform many
laboratory investigations that lead them to actually "see"
that their predictions and ideas were not correct. Many
times these laboratory investigations were not ”planned”. I
had a student tell me that he did not see why oxygen was
necessary for germination because the seeds were under soil,
anyway, and therefore could not be receiving oxygen. .Another
student suggested that as long as the soil wasn't ”packed” it
was receiving oxygen. This was a perfect opportunity to test
it and make observations. So, students set up an experiment.
Keeping all other variables the same, they put a seed packed
in soil, and one with the soil sprinkled on top and observed
their growth (or lack of). It took an actual investigation
to convince the first student that the seed did, indeed,
receive oxygen in the soil. This lead to many other
discussions by students suggesting that water contains oxygen
and maybe the oxygen was taken from.the water, leading to
further investigations. Students needed to test hypotheses
for themselves to find how things worked and fit with what
they already knew’to be true of the world.

Obviously, it was necessary for me to make my classroom.
and instruction more student-centered. Students worked in
pairs to plant their Fast Plants and.worked in cooperative
groups to solve problems and perform laboratory
investigations. In addition, students recorded data on their

fast plants in journals, they constructed concept maps to

32

show connections between ideas, and we had whole-class
discussions to share ideas. Students constructed plant
models, they dissected plants for plant part identification
and the functions of these parts, and they used a computer
program.showing how'photosynthesis, respiration, and
transpiration work including the parts involved in these

processes.

LABORATORY I NVEST I GAT IONS

The following are rationales and summmaries of
laboratory investigations that were developed during my
research at M.S.U.. They are all new to this unit and.were
adapted from Prentice Hall, Merrill, ”Focus on Life Science",
1987, and the "Fast Plants" manual,‘Wisconsin Fast Plants
Program” University of‘Wisconsionadison Department of Plant
Pathology (Full labs are found in Appendix B). I chose those
labs that would best help students reach the unit objectives.
They also needed to be appropriate for seventh graders.

The evaluation section of these labs is based on teacher
observation and student answers to the lab questions. A.more

in-depth evaluation of students is in the Evaluation section.

PHOTOSYNTHESIS: AN INTRODUCTION

RATIONALE :
This lab will enable students to explain the role of light

carbon dioxide in.photosynthesis.

SUMMARY:

Students are to test Coleus leaves for starch (stored food)

grown under various light conditions to see how light effects

photosynthesis. First, they test a Coleus leaf that has been
in the light by boiling it, leaching it using alcohol, and

testing it (using Lugol's solution). Students should find a

33

34

lot of areas with starch. Secondly, have students take a leaf
that has been in the dark for 24 hours and stain it (using
the same procedure). Students should find just a.very few
areas, if any, with starch. Thirdly, have students take a
plant that has been in the dark for 24 hours, cover a portion
of several of the leaves with paper cards and tinfoil, place
it in the light for 24 hours, and stain a covered leaf for
starch. Students should find the areas that were covered did
not have starch because the light could not reach these parts
therefore, photosynthesis could not occur and thus, no
starch.

Lastly, take a destarched (One that has not been in light for
72 hours) Coleus plant and place it in a tightly sealed bell
jar with potassium hydroxide to see the effect carbon dioxide
has on photosynthesis. Students should find that because the
potassium.hydroxide absorbed the carbon dioxide the plant did
not have enough carbon dioxide for photosynthesis and they

should find no starch on the leaf.

EVALUATION:

In most cases, the differences between the plant in the light
and the plant that ended up having a portion of its leaf
covered for 48 hours were obvious but students had a hard
time determining the amount of starch with the plant left in
the dark for 24 hours. The difference in amounts of starch
between the one in the light and the one in the dark for 24

hours was not obvious enough.

35
Most of the students understood the idea that plants

need the light in order to make food and.when they lack
sunlight they can not make food, as evident by the lack of
starch in the leaf. One of my lower level students did state
that "without food from the light the plant would die", here

the misconception that the light is the food still remains.

OXYGEN AND PHOTOSYNTHES IS

RATIONALE :

This lab will enable students to explain that one of the by—
products of photosynthesis is oxygen. The amount of oxygen
produced by a plant during a period of time can serve as a

‘way of telling how'much photosynthesis is taking place.

SUMMARY :

Students will make two identical set-ups and place one in
the dark and one in the light.

Each set-up will contain a cut Elodea plant placed under a
funnel in a jar. Take a full test tube of water and invert it
over the stem.of the funnel. After 24 hours, measure the
height of the gas column collected in each test tube.
Students should find that in the test tube in the dark
produced no gas column as no photosynthesis occurred. The
test tube in the light should have a gas column because

photosynthesis did occur producing oxygen.

3 6
EVALUATION :

I ended up doing this experiment as a demonstration. I had
students make predictions as to what would happen in each of
the two set-ups. My higher-level students correctly
predicted the tube in the light would produce a gas, oxygen,
to replace the water but my lower-level students predicted
that the tube in the light would also produce a gas to
replace the water but thought that carbon dioxide, not
oxygen, was given off during photosynthesis. It was
necessary, then, to prove to them that this was indeed
oxygen, not carbon dioxide.

The students came up with different things they could try to
test if it was oxygen. One student suggested striking a

match and if it remained lit the gas must be oxygen.

PLANT RESPIRATION

RATIONALE :

This lab will enable students to describe how plants obtain
energy through respiration. During this process, carbon
dioxide is given off as a by-product. This gas is colorless
and odorless but can be detected by bromthymol blue which is

an indicator for carbon dioxide.

37
SUMMARY:

Students will put water in one test tube and a solution of
bromthymol blue in another. They will place an effervescent
tablet in the water and stopper it with a tube running to the
tube containing bromthymol blue. Students should find that
the bromthymol blue changes to a green/yellow color in the
presence of carbon dioxide. Next, students will take a flask
of bromthymol blue and blow into it with a' straw. Again,
because we breathe out carbon dioxide the bromthymol blue
should change colors. Lastly, have students take soaked lima
bean seeds and put them in a tightly sealed jar with a beaker
of bromthymol blue. Students should see a change in color of
the bromthymol blue as the beans are respiring, thus giving

off carbon dioxide .

EVALUATION:

Students were pretty easily convinced that plants release
carbon dioxide during respiration because the results were so
obvious. Students always think of plants "breathing" in
carbon dioxide and "breathing" out oxygen. This lab was an

excellent way to show that both of these processes occur.

GERHINATION OBSERVATION

RATIONALE:
This lab will enable students to explain what occurs in the

first stage in the life cycle of a plant. The seed remains

38

dormant until environmental factors such as temperature and
availability of oxygen and water are sufficient for

germination.

SUMMARY :

Students will place ten Fast Plant seeds across the top half
of a petri dish which is covered with an absorbent material.
Cover the petri dish with the bottom half and place at an
angle in two centimeters of water under the light bank.
Observe for four days. Record information each day about the
number of seed coats split, the number of radicles emerged,
the changes that occur in the hypocotyl, and the changes in
root length. Students should find that on day 2 most of the
seed coats have swollen and split, by day 3 the radicles and
cotyledons have emerged and the hypocotyl has changed from
purple to green (presence of chlorophyll so photosynthesis
can begin), and by day 4 the hypocotyl is totally green. With
each day the roots grow longer (reach deeper in the soil for

nutrients and water).

EVALUATION :

Because this was an observational activity, students had no.
problem stating what they saw, but they did have some
difficulty in determining what conditions were necessary for
germination. Therefore, we needed to set up other
experiments. Students set-up some seeds with‘water and air

but denied them light. Then they provided them with air but

39

no water and light. We set up as many different varieties as
people wanted and had them record all of their results in

their journals. The students finally did conclude that for a
viable seed to germinate all three parameters : oxygen, water,

and sunlight were necessary.

TRANSP IRATION

RATIONALE:

This lab will enable students to determine the rate of
transpiration in a given plant species and to explain how
certain environmental conditions affect the rate of

transpiration in plants .

SUMMARY:

Using a potometer students will test to see how much water is
lost from the leafy shoot of various plants in several
experimental conditions. They will test it with no added
factors (control), they will test the shoot under a
spotlight, near a fan, with Vaseline on one surface, and
with Vaseline on both surfaces. Students should find that
the rate of transpiration, from highest to lowest, was: with
the fan, with the fan and one surface covered with Vaseline,
with the spotlight, and with both surfaces covered with

Vaseline .

4O
EVALUATION :

This activity was also done as a demonstration because we did
not have enough materials to make potometers for the entire
class. Students were able to see that certain environmental
conditions affect the rate of transpiration. I had students
tell me what each of the experimental conditions tried with
the leaf simulated in nature. Students related the fan to
wind and the spotlight to sunlight, for example. The problem
with this lab was that the amount of water loss was so small
it was hard to measure. It did not make a drastic enough

change to impress students.

HOW CAN WE LOCATE AND RECOGNIZE XYLEM IN A CELL?

RATIONALE:
This lab will enable students to locate and recognize xylem

tissue in a stem and explain its function.

SUMMARY:

Students will stand a celery stalk in red food coloring for
24 hours. The dye will allow students to see the Xylem
tissue. Students will observe the tissue under the low and

high power lens of a microscope and draw what they see.

EVALUATION:
The vascular tubes in celery are very large and easy to see.

Students were totally fascinated with this lab. They could

 

 

Th
th.
flc

the

41
actually see and pull off individual xylem tubes. The

important thing students learned from this lab was that both
xylem and phloem tissue are conducting vascular tissue but
phloem conduct from top to bottom and xylem from bottom to

top .

FLOWER DISSECTION

RATIONALE:
This activity will allow students to identify the parts of a

flower and give the function of each part.

SUMMARY:

Each student will be given a flower from a geranium plant.
They are to find with an eye glass, the pistil, stamen,
ovary, sepals, and petals and tell the function of each.
They will identify the pistil, stigma, style, anther, and
filament and give their functions. They will also take each
of these parts and scotch tape them to index cards with the

appropriate labels .

EVALUATION:

The students saw many flower models around the room and in
the book, but it is hard for students to relate this to the
flowers they see every day. Students had a hard time finding

the ovary, as they often had to dig for it. It was also

42
difficult for them to differentiate between the stamen and

the pistil. I decided to give them another type of flower
that did not have the same number of stamens and looked a
little different so that they could see that they were

comprised of the same parts although they looked slightly

different.

PLANTIMODELS

RATIONALE:
This activity will allow students to construct a plant model

'with all of the necessary parts.

SUMMARY:

The students will be provided with a variety of materials
i.e. construction paper, pipe cleaners, packing peanuts,
cotton, glue, craft sticks, etc. and be asked to construct a
three-dimensional model of a plant that includes all of the

parts of a plant.

EVALUATION:
Students had already done the flower dissection and had
observed the parts of a plant on their fast plants so were

able to construct these models with very little difficulty.

43
FAST PLANTS/ FAST PLANT JOURNALS

RATIONALE :
This activity will allow students to observe the life cycle

of a flowering plant.

SUMMARY:

In pairs, students will plant a quad of fast plants. Over a
period of 35 days (the life cycle of a Wisconsin Fast Plant)
students will make observations and.measurements and record

this information in a journal on a daily basis.

EVALUATION:

Students were able to observe germination, the development of
cotyledons, true leaves, flower buds, and flowers. They were
able to pollinate, observe the elongation of the pistils,
seed pod development, and the harvesting of the seeds. I was
also able to include some graphing. we took a class history
of plant heights on certain days or the number of seeds
harvested per quad and graphed this information using line,
bar, and pie graphs. From their observation students were
able to give a chronological description of the life cycle of

a flowering plant.

44
CONCEPT MAPPING

RATIONALE :
This activity will allow students to make connections between

the concepts in the unit and everyday experiences.

SUMMARY :

The students will construct 5 concept maps. They'will
include vascular plants, respiration, photosynthesis,
transpiration, and germination. Students were given a list
of vocabulary words for each concept map and asked to show

how they were all related.

EVALUATION :

See attached concept maps in.Appendix D. The concept maps

were done by my core group after instruction. The bold, or
darker marks, were made by me. In a few instances students
were not sure how a concept was related to others and some
misconceptions were still believed at the end of the unit

but, for the most part, students made accurate maps.

EVALUAT I ON

The evaluation of this unit took on many facets. The
students were given a pre and post-test. Students conducted
laboratory investigations (see Appendix B;Evaluation in
previous section) and constructed concept maps (Appendix C).
I facilitated student interviews and informal discussions.
All of the information presented below is from the core group
consisting of 2 low-achieving students, 2 average students,

and 2 high-achieving students .

A. PRE AND POST TESTS

PRE-TEST :

The first question asked was: What is food for

plants? Explain your answer.

Prior to any instruction, the answers to this question

were as follows :

LOW-ACHIEVING STUDENTS- (1) "Sun and soil because the
soil holds the minerals and the roots suck them up. Sun
because the leaves get it and turns it into sugar." (2)

"Sunlight, water, air with these things they make food.

45

46
AVERAGE STUDENTS- (1) "Food for plants are water,

nutrients, sunlight, fertilizer, and soil because they all
keep the plant living and make it grow. " (2) "I think water
and sun are food for plants because if the plant doesn't get

those two things it dies. "

HIGH-ACHIEVING STUDENTS- (1) ”Food for plants is a
substance called glucose, which is made from water, oxygen
and minerals.” (2) ”Minerals, it needs it to stay alive.

Fertilizer makes it grow.”

POST-TEST:

The same questions were asked to these same six students

on the post-test. Here are their responses:

LOW-ACHIEVING STUDENTS- (1) "Glucose it makes in
photosynthesis. When water and C02 and sunlight mix make
photosynthesis." (2) ”Glucose-it is a sugar it uses as

food."

AVERAGE STUDENTS- (1) "Food for plants is glucose,
fertilizer, minerals, and C02 or 02." (2) "Glucose and sugar

because water and sun make the food, they aren't the food."

47
HIGH-ACHIEVING STUDENTS- (1) "Glucose is food for

plants. Glucose is made during the process of
photosynthesis. It is made of carbon dioxide, water,
sunlight, and chlorophyll." (2) "Glucose is food for plants.
They use light, minerals, and water to use in photosynthesis

to make glucose, but glucose is their food."

The second question on the test was: Describe the life

cycle of a flowering plant.

PRE-TEST :

LOW-ACHIEVING STUDENTS- (1) "

 

 

 

 

 

 

 

(2) "

 

48

AVERAGE STUDENTS- (1) "

 

 

 

 

 

 

 

 

 

 

(2) "The life cycle of a plant is sprouting, getting leaves,

 

then flowers . "

HIGH-ACHIEVING STUDENTS- (1) " (1) seed, (2) sprout, (3)

leaves form, (4) Flowers, (5) withers and dies." (2) "

 

POST-TEST:

LOW-ACHIEVING STUDENTS- (1) " First there is a seed,
then a cotyledon, then flowers, and then it dies." (2) "First
germination happens, then roots begin, to grow, then flower

buds grow, then seed pods form, then the plant dries up.

49

AVERAGE STUDENTS- (1) " First is germination then
cotyledons, true leaves, flowers, and then seed pods." (2)
"The life cycle of a flowering plant is cotyledon, true

leaves, flowers, and then seed pods."

HIGH-ACHIEVING STUDENTS- (l) "Germination is the first
step, it is the early growth stage of a plant. Then comes
cotyledons, the cotyledons store food (glucose) until the
plant can make its own. After that are true leaves. True
leaves make glucose. The next step is flowers . Reproduction
takes place in the flowers. Pollination is when pollen is
transfers from the anther to the stigma (during this
reproduction also occurs)." (2) "The life cycle of a
flowering plant goes first is the seed, then it breaks open,
then are roots which absorb water, then cotyledons which hold
food, next is true leaves that is where photosynthesis takes
place, then flowers which holds the pollen and is where

reproduction takes place. "

The third question was: Do plants breathe? Explain

your answer .

50
PRE-TEST:

LOW-ACHIEVING STUDENTS- (1) " Plants do breathe. They
breathe C02 and breathe out 02" (2) " Yes, because without

air they would not live."

AVERAGE STUDENTS- (1) “Yes by there roots so they can
live.” (2) "Yes I think plants breath because plants produce

02."

HIGH-ACHIEVING STUDENTS- (1) ”No, breathing applies to
oxygen (inhaling) plants need C02 which they get from.the
soil, water, and minerals. (2) "Yes, they breathe because

they need oxygen."

POST-TEST:

LOW-ACHIEVING STUDENTS- (1) " Yes, they breathe mostly
C02 and give off 320. (2) " Yes, but it is really called

respiration."

AVERAGE STUDENTS- (1) "Plants inhale C02 and exhale 02
or the other way around because all living things have to
breathe." (2) "Yes, plants breathe because plants take in
C02 and take out 02 for us. Also plants use 02 to live and

grow just like us."

51
HIGH-ACHIEVING STUDENTS- (1) " Yes, plants take in 02,

but very little, they release C02, or Vice versa. (2) " Yes,
flowers breathe because they take in C02 and let out oxygen,

but no because they don't have lungs.

The last question was: If you were a plant what

would your concerns be?

PRE-TEST :

LOW-ACHIEVING STUDENTS- (1) " I would get some sun. I
would not want to be stepped on. (2) " To have food and

water . "

AVERAGE STUDENTS- (1) "Right amount of water, being
healthy, and getting lots of food." (2) "If I was a plant my

concerns would be getting water and sun. "

HIGH-ACHIEVING STUDENTS- (1) "I will still be alive
tomorrow, am I getting enough water and minerals, and how
many toxins are in the ground . (2) "I need oxygen, minerals,

sunlight, and water. "

52
POST-TEST:

LOW-ACHIEVING STUDENTS- (1) "There would be acid rain,
not enough sunlight, I won't get enough water. " (2) That I

make enough glucose to live.”

AVERAGE STUDENTS- (1) "I need sun, C02 and 02, moist
soil and room to function. " (2) ”My concerns if I was a plant
were to get plenty of water, soil, and sun. Without those
three things I would not be able to live because I would not

be able to make my own food.”

HIGH-ACHIEVING STUDENTS- (1) "I am afraid of pesticides.
They will kill the bees that pollinate me." (2) ”My concerns
are that I'm not covered with something so I can get water
and light, I still have roots like no one cut them off, and
pesticide isn't spread around because it could kill me or

bees which are needed for pollination and reproduction. "

ANALYS I S :

The pre and post-tests gave me some amazing insight into
what students already knew, thought they knew, and their
misconceptions. On the first question, What is food for
plants?, I thought it was interesting that the low-achieving
student knew, prior to instruction, that plants make their

own food and the average and high-achieving students did not.

53

After instruction, all students said that plants make their
own food but there were still some misconceptions on what
materials are necessary for this process.

On the second question, the life cycle of a flowering
plant, prior to instruction, most students showed that the
plant started as a seed, produced leaves, then flowers, and
then it dies. .After instruction, the high-achieving students
were able to describe the life cycle in much greater detail
using words such as germination, cotyledons, true leaves,
reproduction, pollination, and photosynthesis. The low and
average-achieving students were able to write down the cycle
versus drawing pictures.

On the third question, Do plants breathe?, prior to
instruction, all students felt there was some need for air
but they were not sure how it was done or why it was needed.
.After instruction, one lowaachieving student was able to call
the process respiration but students were still confused on
which gas is taken in and.which is given off.

On the last question, ("If you were a plant what would
your concerns be?"), prior to instruction, most students felt
their needs as a plant would be very similar to needs as a
person. i.e. getting enough food, water, and sunlight. .After
instruction, these concerns were the same but they could be
more specific such as needing C02, water, and sunlight to
make food and being pollinated to reproduce.

The pre and post tests required written responses. I

felt the students did not put down everything they knew about

54

the questions so I asked these same questions, with their
answers in hand, and asked them to expand on them in the
student interviews. The student interviews gave me an idea
of what activities students liked best as well as which
activities were most helpful in meeting the objectives
(Appendix.A).

The most popular activities seemed to be the growing of
the Fast Plants, the plant models, flower dissection, and the
xylem lab. These activities were all hands-on with very clear
results. I think they were most popular because students
could relate to them in their everyday experiences. .All
students have seen flowers, wondered about the'parts (what
they are called and what each one does), and how the food and
water get to various parts of the plant.

Before beginning this unit, I asked students what they
thought they knew about plants and after instruction they
were asked the same question (see Part D). Prior to
instruction, students strongly defended what they knew with
certainty i.e. they grow in the ground, they need sunlight
and water, so it was difficult of see what misconceptions
existed. One misconception came out of this-they take out 02.
At this point some of my students already knew that plants
made their own food. After instruction, they were able to add
to the first list and tell me WHY things from the prior list
were true (or false) and could provide evidence for their

reasoning.

55

After instruction, I provided students with
words /concepts from the unit and they were to construct
concept maps showing how these terms were related (Appendix
C). The only misconception that still existed at this point
for two of the students was that they still believed it was
02, not C02 that was necessary for photosynthesis. The
concept maps are an excellent representation of how these six
different students, from all different levels, make
connections between the concepts , prior knowledge , and

everyday experiences .

B. NEW TEACHING STRATEGIES

As evidenced by the evaluation portion, the constructivist
teaching method applied to this unit was a huge success. I
believe the key to its success is in its ability to allow
students to prove themselves wrong. Students are wrong on
many occasions. I find that on those occasions if I tell
them they are wrong and then tell them the right answer they
would respond with their original answer if I asked them the
same question the next day.

With the constructivist teaching, I did not tell
students that their answers to the pre-test were wrong, or
that their before- instruction brainstorming list was
inaccurate; I lead them through various laboratory
investigations and other hands-on activities, allowing plenty

of time to discuss their findings with their peers, and,

56

because they had constructed their own, new ideas, it was
these they remembered.

As evidenced by the concept maps (Appendix C) students
were able to make connections between their own prior
knowledge, everyday experiences, and the scientific concepts.
The pre and post-test (being open-ended) allowed students to
explain, through words or pictures, their ideas about the
questions. In this way, I received.more information about
what the students knew'because they were not under the
impression that there was only one correct answer (as in
multiple choice tests). The evaluations of the labs
(Evaluation section part D) and allowing students to conduct
their own investigations permitted them to "be" scientists.
Students posed questions about their fast plants (Howhmany
seeds, per quad, did our plants produce?), made predictions,
tested their predictions (broke open the pods and counted the
number of seeds produced), recorded the results, and analyzed
their data (made a graph showing how many seeds each quad
produced), and, finally, to reach a conclusion based on their

findings.

C. STUDIHHP INTERVIEW"!

I interviewed the same six focus students that I used
throughout my unit. There were two high-achieving, two
average, and two low-achieving students. The students were

chosen randomly, as previously described.. There are five

57

males and one female. I was CO-teaching this hour, so I was
able to take each student out for approximately 20 minutes
while the other teacher conducted class. I paraphrased what
the students told me from a tape—recording. I tried to use
their words as much as possible but they are not direct
quotes . The average and high-achieving students were
interviewed together because two of the students were
uncomfortable being interviewed one on one. I did include
both students ideas.

I asked the students a variety of questions about the
activities we did throughout the unit. What activities did
they like best? Least? Why? What did they learn from the
various activities? How does it relate to their lives, do
they think they would use these concepts in their lives?

Their paraphrased interviews are presented below:

key: Ll= low-achieving student #1
L2= low-achieving student #2
A1= average student #1
A2= average student #2
H1= high-achieving student #1

H2=high-achieving student #2

L1: I liked the fast plants the best, especially taking
apart the seeds and finding all of the parts. They really
helped me learn the life cycle stages of the plant. I liked

the flower dissection next best. We took apart and labeled

58
the parts . We also had to find out what part did what. The

flower models helped me learn the parts and the functions of
each part. The photosynthesis lab showed us how the plant
makes food in light and that the more light there was the
more food it could make. The xylem lab showed us that
different tubes do different things. The xylem carries stuff
up and the phloem carries stuff down. This stuff helps me
take care of my plants at home because now I know that they

need light and water and air to live.

L2: I liked the xylem the best because you could actually
see the xylem tubes because of the red food coloring. Not
only could you see it well but we could actually pick it out
and look at it under the stereoscope. I learned a lot from
the photosynthesis lab also. The plant who was put in the
dark for a long time didn't get sun so it couldn't do
photosynthesis and it didn't have very much food in its
leaves. The plant that was in the light made the most food.
The flower dissection and flower/plant model taught me the
parts of the flower and what they do. I thought growing the
fast plants was a good idea because you could actually see
the stages the plant goes through. I think I will do a
better job of growing my plants at home because now I know
how much light and water the plant needs and why it needs

those things .

59
A1 8 A2: We liked the flower/plant model the best because we

could be creative. We learned where things were, what order
they were in, and what each part did. The xylem lab was cool
too because we could actually cut out the xylem tubes because
of the food coloring. The photosynthesis lab showed us why
the plant needs sunlight. The sunlight is the energy the
plant needs to make glucose-food for the plant. The fast
plants were neat to grow it taught us where things were and
in what order things happened. After learning all of this we
could work in a greenhouse because now we know what the

plants need.

El & HZ: We liked the flower/plant models the best because
putting all of the stuff together helped us remember what the
parts were and what each part did. The fast plants allowed
us to see the growth and see the different stages the plants
go through instead of you just "telling" us what they do. It
was helpful to dissect a real flower because then you could
look at all of the parts and know what they are really like.
The Xylem lab proved to us that the xylem tubes actually do
carry water up the plant. We know this now because we saw
it. The food colored water actually stained the celery and
the leaves on top of the celery so it must have traveled up
the xylem tube. The photosynthesis lab showed us that light
was necessary for the plant to make food. The plant made
more food in light than it did in the dark. We did an iodine

test to test for starch which is the stored form of glucose.

60

The sugar made by plants in photosynthesis. .Anyone who is
going to make a living in plants, or even a farmer, needs to
know what plants need to live. These activities were more
fun than if we just followed to book. we understood it

better.

D. SUBJECTIVE EVIDENCE-INFORMAL DISCUSSIONS

Prior to teaching the unit I asked the students what
they ”thought they knew“ about plants. .All answers were
accepted and we did not judge them as correct or incorrect at

this time.

PRIOR TO INSTRUCTION

-Fertilizer helps them grow

-They grow in the ground

-Some are green and some are brown
-They need sunlight and water to grow
-some have white stuff in them

-They breathe C02

-They take out 02

-Without them we could die

-They make chlorophyllawhich is a natural sugar made from.C02
and sunlight- in leaves

-Some produce food or make medicine

-some make diseases-some cure diseases

6 1
-They make paper

-Animals love living in them and eating them
-They have roots

-Everything would die without them.

AFTER INSTRUCTION

The students realized they did have misconceptions on
their before-instruction list and they crossed those off or
changed them. The students also added new things to the list

that they had learned throughout the unit .

-Fertilizer does help them grow because when we grew our fast
plants we used fertilizer and in the quad that did not have
fertilizer did not grow or at least not as well.

-They do grow in the ground-soil to be more specific- but
they can grow in water because there are aquatic plants .
-Even though plants (flowers) are all different colors they
have green on them for photosynthesis .

-They do need sunlight and water to grow but they also need
chlorophyll to capture the sunlight for photosynthesis, C02,
minerals, 02 for respiration, and other nutrients

-They do not breathe C02 ; They respire and 02 is needed for
this process.

—They do release 02 through photosynthesis

-We still think we would die without them because they

provide us with 02 and are important in the food chain

62
-They make glucose (not chlorophyll) the chlorophyll in the

leaves captures the sunlight to make this sugar

-Some plants are used as food in the food chain and they do
make medicines

-Some plants do cause and cure diseases

-We make paper using trees- the trees don't make the paper
-Animals do use plants for habitats and food

-They do have roots

-Many things would die without them

The students all tested well on their plant units which
included the four post-test questions listed above in
addition to 25 multiple choice questions. The lowbachieving
students received a 70% and a 75% respectively. The average
students received a 89% and a 78% respectively. The high

achieving students receives a 95% and a 90% respectively.

 

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DISCUSSION AND CONCLUSIONS

A. ASPECTS OF NEW ”HANDS ON" MATERIALS IN
UNIT PARTICULARLY EFFECTIVE IN CONVEYING

KEY INFORMATION

The most effective aspect of the unit, as measured by
the student interviews and my observations, ‘was the use of
the fast plants to show the life cycle of a flowering plant.
The students were able to ”be" scientists. Students posed
questions about their fast plants and, made predictions
(hypotheses) about the growth of the plants. They were able
to test their predictions, record the results, analyze their
data (they graphed information, drew'pictures, and.made
measurements), and, finally, to reach a conclusion based on
their findings. They were able to use the scientific method
repeatedly throughout this segment of the unit. One of my
goals for myself, as a teacher of science, is to focus more
on process i.e., how'can.we find the answers to our
questions, and using‘Wisconsin Fast Plants allowed me to do
this.

One of the best examples of this was the germination
observation activity. Students posed the question "What do
seeds need to germinate?". They then stated an hypothesis,
set up an experiment, recorded their results on a daily
basis, graphed the results, and were able to state a

conclusion (that seeds need oxygen, water, and proper

63

 

 

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64

temperature for germination). They were able to test their
hypothesis for themselves and actually see the results
instead of me telling them.

The dissection of flowers and the making of the flower
models was very effective in teaching students the parts of
the plants. In the past, they would look at a picture in the
book to identify flower parts. This time students examined
real flowers with their hands and eyes. After dissecting the
flowers I had them look at their fast plants and identify
these same parts. I have never had students grasp the
pollination of plants as I did in this unit. We made bee
sticks (with dried bees) and students actually went around
and pollinated each others plants. They were then required
to describe (in pictures, words, re-enactment) the process.
The combination of understanding the flower parts and their
functions, in conjunction with the pollination of plants
really helped students with this objective.

The plant respiration lab was effective in showing that
plants do respire and do require oxygen for this process. It
was particularly effective because it was a very drastic and
noticeable color change of the bromthymol blue from blue to
yellow.

The use of celery for identifying the xylem tubes also
was effective. The food coloring showed the
”tube” that water takes as it travels up a plant and left
nothing to the imagination. This also allowed students to

realize that, although they could not see it, phloem tissue

65

is a conducting tissue that conducts from top to bottom,

carrying food as it goes because food is made in the leaves.

B. ANALYSIS OF WHAT WAS EFFECTIVE

The constructivist teaching approach was extremely
successful in this unit. The basis of this strategy is to
have students as active learners responsible for constructing
their own knowledge. ‘With the use of hands-on activities,
laboratory investigations, model-making, pre-testing,
clinical interviews and other student-centered activities,
students had.many opportunities to dO‘thiS.

I found the use of concept maps especially useful in
this construction of knowledge (Appendix C). Concept mapping
allowed students to make connections between the concepts
taught in the various hands-on activities and everyday
experiences. ‘What I thought ‘was fantastic is that no two
student concept maps were exactly alike. No two students
constructed knowledge in the same way because each student
came to the unit with different experiences. I made a unit
concept map (Appendix D) showing the connections I made
between ideas. I looked to make sure students connections
were correct (made sense-no misconceptions) but it was not
necesarry that it look like mine or like each others.

I have already begun.adding many aspects of this unit to
my other units. Constructivism is a strategy, a way of

thinking, that can be applied to any unit that I teach. I

66

have also found that my students leave my class excited about
science and tell their friends some of the things they have

been doing in my class. These friends then tell their Science
teachers and I have actually had some of these teachers ask

me about this strategy and the activitesit
C. ASPECTS OF THE UNIT THAT NEED IMPROVEMENT

A few of the laboratory investigations I chose did not
work very well and will need to be improved or exchanged for
a different lab that will illustrate the same concepts. The
differences in the amount of starch between the three plants
with different treatments in the photosynthesis lab was not
significant enough to convince students that light is needed
for photosynthesis to occur. If I made the time differences
more extreme among the three it may help.

The transpiration lab was supposed to show that certain
environmental conditions affect the rate of transpiration.
The amount of water loss was so small it was hard to measure
and was not a significant change. If I exposed them to the
"condition" for a longer period of time and made the
"condition" more extreme the water loss may have been more
significant.

Next time I teach this unit I would like to spend
another week on the unit to allow more time to analyze the
plant journals. I had students taking measurements and

making observations on almost a daily basis. The students

67

were able to graph some data and share data; however, it
would have been nice to discuss why different groups may have
gotten different results and been able to set up some

experiments to test their hypotheses.

D. OVERALL EVALUATION AND CONCLUSION

I feel the combination of the constructivist teaching
strategy in.conjunction with the laboratory investigations,
hands-on activities, and concept mapping lead students to an
understanding of the following scientific principles: (1) the
classification of organisms into major groups on the basis of
their structure (2) the life cycle of a flowering plant (3)
evidence that plants make and store food and (4) how selected
systems and processes work together in plants.

In using the constructivist approach, students were able
to take ownership for what they have learned because it is
knowledge they constructed based on their own experiences and
prior knowledge. In allowing students to construct their own
knowledge, we have made them active learners who will
remember what they have learned because it fits in their

world.

APPENDICES

APPENDIX A

APPENDIX A

OBJECTIVES

(As taken from the MEGOSE-Living things)

US I NG OBJECTIVES

To explain

(Ul) - Explain why specialized cells are needed by plants and
animals.

(U2) - Explain how selected systems and processes work
together in animals and plants.

(U3) - Explain how water and food moves through a plant.

(U4) - Explain why plants placed in the dark will eventually
die.

(U5) - Explain how a plant gets its food.

(U6) Explain how a plant stores its food.

(U7) Explain how a plant regulates water loss

(U8) - Explain how a plant converts foods into energy and

waste materials .

To describe

(U9)- Describe the life cycle of flowering plants.

(U10)- Describe evidence that plants make and store food.

68

69
To predict

(U11)- Predict whether plants will grow or live without
light, water, and carbon dioxide.

(U12)- Predict whether plants will grow successfully under

various conditions .

To design

(U13)- Design controlled plant experiments.

(Ul4)- Design a system for plants to grow successfully.

CONSTRUCTING OBJECTIVES
(Where students construct knowledge)
(Cl) - Generate scientific questions about the world, based
on Observation.

(C2) - Design and conduct simple investigations.

(C3) - Use measurement devices to provide consistency in an
investigation .

(C4) — Construct main ideas necessary for them to conclude

that we would have no food if there were no green plants.
(C5) - Construct main ideas necessary for them to conclude

that we would not have enough oxygen if there were no green

plants .

REFLECT ING OBJECTIVES

(R1) - Evaluate the strengths and weaknesses of claims,

arguments , or data .

APPENDIX B

APPENDIX B

COMPLETEILABORATORY”WRITE-UPS
XYLEM.AND PHLOEM LAB

In the process of photosynthesis, green plants
manufacture carbohydrates from raw materials - carbon dioxide
and water using sunlight as an energy source. Carbon dioxide
enters a plant through the stomatas in a leaf. Water enters
a plant through the roots. From the roots, the water passes
up the stem and eventually reaches the leaves. After the
leaves manufacture the carbohydrates , the synthesized
material is transported from the leaves to the stem and the
roots. Conducting (vascular) tissue in the stem- the xylem
and phloem- provides the passageway between the leaves and
the roots.

By using a dye, you will be able to locate the tissue
that conducts substances upward in a plant stem. You will
then examine this tissue under a microscope.

*This lab was tested at MSU, summer 1995

-1 celery stalk per pair

—1 beaker with food coloring and water
-1 dissecting knife

-1 stereoscope

An

1. Obtain a celery stalk.

2. Cut it about an inch from the bottom and stand it in water
containing dye.

3. Let it stand for 24 hours.

70

71
B.
1. Remove the celery from.the dyed water and rinse it under
running water to remove the excess dye.
2. Hold the plant toward the light.
3. What evidence is there that the dye has or has not reached
the leaves?

C.

1. Cut a thin slice, about 1-2cm in thickness, from the
bottom end of the stem.

2. Discard the slice.

3. With a hand lens, examine the cut surface of the remaining
stem.

4. Make a drawing of this cross section on a separate piece
of paper and indicate the location of the dye.

D.

1. Cut off another l-2cm slice of stem.

2. Place this slice in a drop of water on a slide and set it
aside for a while.

3. Lay the long remaining piece of stem on the table and
carefully shave off the epidermis and the thin layer of
tissue underneath it. Stop shaving the stem when you see one
or more thin colored lines .

4 . What evidence is there that the dye has or has not moved
upward through specific tissue?

E.

1. Take the slide on which you have placed a thin slice of
stem (from part D-2) .

2. Cut this slice of stem lengthwise into four strips.

3. Select a strip that shows the colored dye and discard the
other strips.

4. Move the remaining strip to the center of the slide and
cover the strip with another drop of water.

72

5. With dissecting needles, tease apart the tissue as much as
possible.
6. Apply a cover slip and press down firmly on it with the
blunt end of a pencil.
7. Absorb any excess fluid on the slide with a piece of paper
towel.
8. examine the specimen under low'power.

(the stained tissue is Xylem)
9. Change to the high power and explore the xylem tissue.
10. On a separate piece of paper, make a drawing of the xylem.
tissue.

QUESTIONS
1. In a celery stem, where is Xylem.tissue located?

2. How are Xylem tissue cells different from other plant
tissue cells?

3. What is the function of Xylem.tissue?
4. How is Xylemrtissue adapted to its function?
5. Phloem tissue is also present in celery stem. .Although

phloem tissue is a conducting tissue, the dye does not color
it. Suggest a reason for this.

6. Name the tissue that gives rise to Xylem.and Phloem.

73
PHOTOSYNTHESIS :iAN’INTRODUCTION

OVERVIEW

During photosynthesis, plants capture a small amount of the
sun's energy and store it in the chemical bonds of
carbohydrates. The carbon source for this process is carbon
dioxide, which is reduced by electrons fromnwater to form.
glucose (sugar) as follows:

6C02 + 6820 + Energy C631206 + 02
(carbon (water) (glucose) (oxygen)
dioxide)

*This lab was tested at MSU, summer 1995

MATERIALS
-3 Coleus plants

-Alcohol bath
-Boiling water bath
-Lugol's solution

SEC 1: The role of light in photosynthesis
OBJECTIVE: Discuss the role of light in Photosynthesis.
PROCEDURE: PART.A

1. Obtain a leaf from a Coleus plant and place it in boiling
water for 2- 3 minutes.

2. Transfer the leaf from.the boiling water to a beaker of
alcohol, and allow'the green pigment to leach out (20-
30min.). **While waiting do part B.

3. Remove the leaf from the alcohol and place it in a petri
dish.

74
4. Pour Lugol's solution over it. The starch present in the
leaf will stain dark blue-black.
5. Draw the leaf and indicate the starch containing areas.

PROCEDURE: PAM B

1. Obtain a Coleus plant that has been in the dark for 24
hours.

2. Remove a leaf from this plant and stain it for the
presence of starch as described in Part A.***While waiting
set up part C.

3. Draw'the leaf and indicate the starch containing areas.

PROCEDURE: PART C

1. Cover several of the leaves of a Coleus plant that has
been in the dark for 24 hours with paper cards and foil. Be
sure to leave about half of the leaf uncovered.

2. Place the coleus plant in the light for 24 hours.

3. After 24 hours, remove one of the covered leaves and test
it for starch.

4. Draw'the leaf and indicate the starch containing areas.

QUESTIONS

1. Why is the presence of starch an indication that
photosynthesis is occurring?

2. Why is the lack of starch in a leaf an indication that
photosynthesis is not occurring?

75
3. In part C of the investigation, discuss why only the
uncovered portion of the leaf stained positive for starch.

4. In part B of the experiment, what happened to the starch
that was present in the leaf before it was placed in the
dark?

5. Based on your experimental results in section 1, state a
hypothesis involving the need for light in photosynthesis.

76
OXYGENUAND PHOTOSYNTHESIS

OVERVIEW

green plants can turn raw materials into food. Green plants
take in water and carbon dioxide and, in the presence of
light and chlorophyll, turn these chemicals into food. This
process is called photosynthesis. One of the by-products of
photosynthesis is oxygen, produced from the breakdown of
water. The amount of oxygen produced by a, plant during a
period of time can serve as a way of telling how much
photosynthesis is taking place.

*Tested and modified at MSU, sunnner 1995

MATERIALS (per group)
-Water that has been standing 24 hours
-Sodium Bicarbonate (lgm)

-2 Elodea plants (pet stores)

-2 Test tubes

-2 jars

1. Fill each jar with water that has been standing for at
least one day. Add 1 g of sodium bicarbonate to the water in
each jar.

2. Obtain 2 elodea plants and cut about 1 or 2 cm from the
bottom of the stem. Throw away the part you cut off. Lightly
crush the upper 2.5cm of the stem between your fingers.

3. Place an elodea plant into the water in each jar and cover
it with a funnel. Position the plants so that the cut
crushed ends are up.

4. Fill a test tube completely with water. Hold your index
finger over the mouth of the test tube and invert it over the

77
stem.of the funnel. Do not let any water escape from the
test tube. Place a test tube over each funnel.
5. Place one jar near a bright light for 24 hours. Place the
other jar in the dark (control).
6. After 24 hours, measure the height in cm of the gas column
that collected in each test tube.
-Lab‘ taken from Merrill-"Focus on Life Science" 1987

QUESTIONS

1. What proof do you have that light is needed for
photosynthesis?

2. What proof do you have that oxygen is being given off
during the experiment? Before you answer, carefully review'
what you observed during this experiment.

3.‘Why was sodium.bicarbonate added to the water? HINT:
Sodium bicarbonate gives off carbon dioxide when mixed with
water.

The following graph shows the total amount of oxygen given
off by a green plant during a 24-hour period of time.

660

8

 

12 18 24
Time (in hours)

Amount of Oxygen (in Miiiiiiiors) Given
0 8
o

 

78
4. (a) How many hours did the plant receive light?
(b) How many hours was the plant in the dark?
(c) How many milliliters of oxygen were given off between
hours 18524?

5 . Explain what change may have occurred in the light during
hours 18824 that would have decreased the amount of oxygen
given off when compared to hours 0—11?

6. Which graph below best shows the total amount of oxygen
produced if a plant was illuminated for 24 continuous hours?

.k . 3 '(y'

 

Amountochs ‘

FIGURE 19-4.

0 Time 0 0
7. Which graph below best shows the total amount of oxygen
produced if a light source were slowly moved farther and
farther away from the plant during a 24 hour period?

 

 

 

 

 

 

A 8 ’ c

 

FIGURE 19-5.

 

 

 

 

 

 

8 . From this activity, what are the requirements for
photosynthesis to occur? ‘

79
9. Write the equation for photosynthesis .

10. What are the products of photosynthesis?

11. What would happen if there were no green plants?

12. How does the equation for photosynthesis compare with the
equation for respiration?

13. In what cells does photosynthesis occur?

14. In what cells does respiration occur?

80
CARBON’DIOXIDE.AND PHOTOSYNTHESIS

OVERVIEW

The site of photosynthesis in green plants is the leaf. In
order for leaves to make food during photosynthesis, the
plant must be provided with raw'materials. One of the raw’
materials needed is a gas called carbon dioxide. If you can
supply a plant with extra carbon dioxide, will it make more
food?

*Tested at MSU, summer 1995

MATERIALS (Per group)

-2 small plants

-2 plastic bags

-2 1/2 filled paper cups with water
-2 effervescent tablets

-1 pair tongs

-Boiling water bath

-Alcohol bath

-Iodine solution

PROCEDURE
PART.A

1. Examine a prepared microscope slide of a leaf cross
section.

2. Label the cuticle, the upper epidermis, the lower
epidermis,the palisade layer, the spongy layer, and
chloroplasts.

81
PART B

1. Place two small plants inside separate plastic bags.

Place one plant near a light source and the other plant in
the dark.

2. Seal both bags with tape.

3. Place two more plants inside plastic bags. Place one near
a light source and the other plant in the dark. Do not seal
the bags.

4. Place a paper cup half-filled with water in each of the
open bags. Put two effervescent tablets inside each open bag.
DO NOT put the tablets in the cup of water yet. Seal both
bags with tape.

5. Working through the plastic bags, carefully pick up the
effervescent tablets and place them in the cups of water. DO
NOT open the bags.

6. After 24 hours, test the leaves of the four plants for the
presence of food by opening each bag and removing a leaf from
each plant. Mark each one in the following way for
identification. Snip off the tip of the leaf from the plant
left in the dark. Do nothing to the leaf from the plant
placed in the light. Cut a notch in one side of the leaf from
the plant placed in the light with effervescent tablets.

Cut two notches in one side of- the leaf placed in the dark
with the effervescent tablets.

7 . Boil the leaves in water for two minutes.

8. Remove the leaves from the hot water with tongs . Now place
the leaves in alcohol until they turn white.

9. Use tongs to remove the leaves from the alcohol. Spread
the leaves out in a shallow dish. Add water to soften the
leaves . Pour off the water and cover the leaves with iodine
solution. Allow the leaves to remain in the iodine solution
for two minutes.

-Lab taken from Merrill-"Focus on Life Science"-1987

82
DATA AND OBSERVATIONS

1. In data table 20—1, record the color of the three leaves.
Be sure to compare the color of the leaves to on another.
Use such terms as light brown, dark brown, or black.

DOIO Table 20-11
Plant leaf color with iodine solution

 

 

No light
Light ' . . i
Light and carbon dioxide _.

No light and carbon dioxide

 

 

 

 

 

 

QUESTIONS AND CONCLUS IO”

1. What is the function of the cuticle?

2. What is the function of the epidermis?

3. In what parts of the leaf is the chlorophyll?

4. In what parts of the leaf does photosynthesis occur?

5. Why must the plants with the effervescent tablets be
placed in sealed bags?

6. Why were the other plants placed in Sealed bags?

 

83
7. What gas formed inside the bags when the effervescent
tablets were added to water?

8. What is removed from the leaves when they are placed in
alcohol?

9. What does the iodine test tell you about photosynthesis in
plants?

10.‘Which plants have the most food in their leaves? HINT: A
dark.brown leaf color shows much food is present. A light
brown or tan leaf shows little food is present.

11. Which plants carried on the most photosynthesis?

12. What conditions are needed for photosynthesis to occur?

13. Why is a control needed in this activity?

JEOPARDY GAME
OVERVIEW

As a means of review, students will play a jeopardy game.
They will be able to discuss the questions with their teams
to determine the best answer.

1. Class will be split into five groups of six.

2. There are six categories: Classification, Life Cycle,
Photosynthesis, Food Storage, Respiration, and Transpiration.
3. All questions are worth 100 points.

4. All answers must be in the form.of a question

5. Team.one will be asked a question. Thewaill have one
minute to discuss the answer. If they answer correctly they
receive 100 points. If they answer incorrectly they do not
lose any points but team.2 will have the chance to steal for
90 points. If team 2 answers incorrectly, team.3 will have a
chance to steal for 80 points and so on.

6. The second question goes to team 2. Again, they will have
one minute to discuss their answer. If they answer
correctly, they receive 100 points. If they answer
incorrectly, team.3 will have a chance to steal for 90
points. If team 3 answers incorrectly team 4 will have the
chance to steal for 80 points and so on.

7. The team with the most points is the winner and their
total points starts the ”AP's. .All other teams grades will
be determined by a % using the winners points. For example,
if the winners, team 1, had a total of 1000 points and
another team, team.2, had a total of 800 points, team 2 would
receive an 80% or a "B".

85
SAMPLE‘QUESTIONS

CLASSIFICATION

1. These plants contain transport tubes. (Vascular)

2. These plants do not have true roots, stems, or leaves.
(Non-vascular)

3. These plants produce uncovered seeds. (Gymnosperms)

4. These plants usually need.a pollinator or pollinating
mechanism. (Angiosperms)

5. These plants are cone-bearers. (Gymnosperms)

M

1. This is the early growth stage of a flowering plant. It
requires the proper temperature, water, and.oxygen levels.
(Germination)

2. This part of a flower produces the pollen. (Anther)

3. The process where the egg and sperm unite is known as?
(Fertilization)

4. The lst stage of sexual reproduction in a flowering plant
is? (Pollination)

5. The 3 parts that make up the female reproductive organ, or
the pistil, in a flowering plant are? (Stigma, Style, and

OVEIY)

PHOTOSYNTHESIS

1. The green pigment found in the leaves of plants is?
(Chlorophyll)

2. Carbon Dioxide enters the leaf by the process of?
(Diffusion)

3.‘Water enters the cell by a process called? (Osmosis)
4. Food for a plant is? (Glucose)

5. The process whereby plants make their own food is?
(Photosynthesis)

 

FOODlSTORAGE

1. Where food is stored in a seed. (Cotyledons)

2. Food is stored as this in plants. (Starch or sucrose)

3. Vitamins and minerals move through a plant through this
process. (Active Transport)

4. Stored food gets to other plant parts through this tissue.
(Phloem)

5. This provides energy for the plant. (Glucose)

RESPIRATION

1. This process produces energy for the plant. (Respiration)

2. Respiration requires what 2 things. (Oxygen and Glucose)

3. Respiration produces what two things.(Energy and C02)

4. The process of respiration is done by the help of what

organelle? (Mitochondria)

5. The equation for respiration is?
(C6Hl206+602=6COZ+6HZO+Energy)

TRANSPIRATION

1. The process where water is lost in plants. (Transpiration)

 

2. water is lost through the in a leaf. (Stomata)
3. water loss is regulated by? (Guard cells)
4. Stomata are at night? (Open)

5. What affects the rate of transpiration? (Environmental
conditions)

 

87
PLANT RESPIRATION

OVERVIEW

Plants and animals obtain energy through respiration. This
is the process by which food reacts with oxygen to produce
the energy necessary to keep the plant and animal alive.
During respiration, a gas called carbon dioxide is given off
as a waste product. This gas is colorless and odorless but
can be detected by a liquid called bromthymol blue which
changes color in the presence of carbon dioxide.

*Tested at MSU, Summer 1995

MATERIALS (Per group)
-1 effervescent tablet
-1 straw

-1 flask

-2 covered jars
-5 been seeds
-Rubber stopper
-Glass tube
-Bromthymol blue
-2 test tubes
-Rubber‘tubing

    

FIGURE 18-1.
PART.A ‘

1. Assemble the stopper, glass tube, and rubber tubing as
shown in the figure.

88
2. Fill a test tube with bromthymol blue. Record the color of
the bromthymol blue in data table 18-1. Fill a second test
tube half full with water.
3. Assemble the apparatus shown below,

 

 

4. Remove the stopper from.the test tube with water in it.
Drop 1/4 of an effervescent tablet into the water and replace
the stopper quickly.

5. Wait 3 minutes. Record the color in the data table.

PART B

1. Fill a flask 1/4 full with bromthymol blue.

2. Place a straw into the flask and blow through the straw 20
times. Make sure your breath is bubbling through the liquid.
CAUTION: Do not suck any of the liquid into your mouth.
Record the color in the data table.

PARTC

1. Assemble the equipment shown in figure 18-3.

2. Assemble an identical jar with no bean seeds.

3. Cover the jars and keep closed for 24 hours. After 24
hours, observe the color of the bromthymol blue in the
beakers. Record the color in the data table.

-Lab taken from.-Merrill-"Focus on life science"-1987

89
DATA AND OBSERVATIONS

Dcita Table 18-1

 

 

 

 

 

 

 

 

Color of Bromthyrnol Blue
’ ‘ Carifirnrclgigx‘tide Before ‘ After
Effervescent tablet - _ I
'Jhflnanlneafli 4f " :
‘Unulbeanseeds - . - < l -

 

 

 

QUESTIONS AND CONCLUSIONS

1. What gas forms when an effervescent tablet is placed in
water?

2. What color change occurs in bromthymol blue when carbon
dioxide gas is added to it?

3. What gas is present in the air you exhale? What proof do
you have?

4. What gas is given off by living seeds? What proof do you
have?

5. What was the purpose of the jar with no bean seeds?

90
TRANSPIRATION

OVERVIEW

Water is absorbed through the root system of higher
plants and carried upward through the stem.to the leaves.
‘Water is used in plants chiefly in the process of
photosynthesis. However, a large amount of the moved water is
lost by transpiration. Transpiration is a process in which
‘water evaporates through leaves and cools the plant. A.corn
plant transpires about 190 liters of water during a 100-day
growing season. Transpiration is partially responsible for
water movement from roots to leaves in a plant.

In this investigation, you are tO> determine the rate of
transpiration in a given plant species. You are to determine
the effect of certain environmental factors on transpiration
rate.

*Tested at MSU, Summer 1995

MATERIALS (per group)
-1 Leafy Shoot

-Fan

-Spotlight

-Vaseline

-Potometer

PROCEDURE

1. With a razor blade, remove a leafy shoot from.a potted
plant. Place the shoot in a large beaker of water. Holding
the cut end under water, out off 2-3cm.from the cut end of
the plant to remove any air in the xylem vessels. Keep the
shoot submerged in the beaker.

2. With a pipette, fill the potometer by adding water to the
pipette attached to the potometer. Add water until it

 

91
overflows from.the other side of the ”U". When overflowing
occurs, insert the leafy shoot into the rubber tubing. Tie
the cord as tight as possible around the rubber tubing
holding the shoot. Fill the pipette part of the potometer to
the zero mark. No water should leak from.around the shoot.
3. Allow'the shoot to transpire for five minutes. At the end
of five minutes, determine the volume Of water that has
transpired. Calculate the volume of water (mL) transpired per
hour. Record your results in the data table.
4. Refill the potometer to the zero mark on the pipette.
Place the leafy shoot about 1m.from.an«electric fan. At the
end of five minutes, determine the volume of water
transpired. Calculate the amount of water transpired in 1
hour. Record your results in the data table.
5. Repeat placing leaf 1m.from.a spotlight.
6. Repeat placing leaf 1m from fan after you have coated the
UPPER.leaf'with.vaseline.
7. Repeat placing leaf 1m from fan after you have coated
UPPER AND LOWER.surfaces of the leaf.
-Lab taken fromp"Probing levels of life”-1989
DATA AND OBSERVATIONS

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TABLE 54-2. CLASS DATA ON WUNT OF WATER TRANS"
ml. OF WATER TRANSPIRED PER HOUR
TYPE OF PLANT
PETROLEUM JELLY
NORMAL FAN SPOTLIGHT (UPPER SURFACE)
QUESTIONS

1. What environmental factors did you use that increased the
rate of transpiration?

92
2. What environmental factors did you not use that would
increase the rate of transpiration?
3. What environmental factors did you use that decreased the
rate of transpiration?
4. What effect would the size of the leaf have on the rate of
transpiration?
5. What other factors may effect the rate of transpiration?
6. How do the fan, light, and Vaseline increase or decrease
the rate?
7. Did any of these three conditions increase or decrease the
rate of transpiration more than the others?
8. From the class data arrange, in order, from the greatest
to the least, the transpiration rate in the various species
of plants.
9. Why do you think each species of plant transpires at a
different rate?
10. were any controls used in this investigation? Explain.
11. If you were to do this investigation again, what factors
would you be certain to control?
12. How'did these factors affect your results?

 

93
WHAT FACTORS AFFECT RESPIRATION?

OVERVIEW

Both plant and animal cells carry on respiration. In this
experiment, YOU‘Will demonstrate that carbon dioxide and is
produced during respiration.

*Tested at MSU, summer 1995

MATERIALS (PER GROUP)

-Bromthymol blue

—8 test tubes

-2 Elodea (pet store)

-Solution 50mL aquariumnwater and 20mL bromthymol blue
solution

PROCEDURE
YOD‘Will demonstrate that plants respire by testing for the
presence of carbon dioxide.

Bromthymol blue is blue in an alkaline environment, but turns
yellow in an acid environment. Carbon dioxide in the presence
of water forms a weak acid.

1. Prepare a solution of 50 mL of aquariumnwater and 20 mL of
bromthymol blue solution.

2. Fill 8 test tubes to within 3 cm of the top with this
solution.

3. Add a sprig of Elodea to 4 of the test tubes.

4. Place 2 test tubes with Elodea and 2 test tubes without
plants in the dark.

5. Place the other 4 tubes in the light.

6. Observe the tubes the next day.

94
QUESTIONS

1. Why did you leave 4 test tubes with no Elodea?
2 . Which tubes showed a color change?
3. Why did these tubes change?

4. What process has taken place? How do you know?

95

FLOWER PARTS

Observational Exercise for older students

 

L,

. LUngahmdlenscuefuliy'
emnnethebrassicaat‘ast

 

amthefiowerpartsone

 

 

Pianflflower.Compareyom- bymAtoothpickortweezex-s
flowertotbeworkshoetdthe wmhelptosepantetheflower
hudoaflower. parts.
Lem-am
"AMEN
Slandetheflowcrmthemale

poflenmyingknobsealledan-
thcsmtop. Countthenmnber
ofstsmens andnotioehowthey
mmgeduoandthepisfii.

 

 

7.1‘hepistilisthofsmalepct Embahndlngobosrntho
theflower,anditoolleetspoliea mmmma
onitsstiekytop,thestim'l'ho them.’l‘henectafiosseaete
ear-pelmsidethebaseoffln amnesterfioeifyoean
pisfiloantainsthcegsmvales). tuteit.

 

 

 

9.0mhteyourdnwingasing
motherlanssieaflowenm
fimmmpcbmocufios,
anthernoumttoadflhbel
anthem

 

 

96

FERTILIZATION AND SEED DEVELOPMENT

Observational Exercbe

 

 

LObsu-vethefistflsonthean-
pollinated

3.1'hree
dayslater,
lookfior
fisnscf
Pish'l .

 

 

 

Useasb'oagpintoopenidissoct.)
thepodObmvethesizeot'the
amiss.

 

 

 

 

 

\

- 9.Priektheovnleendsqaeue
7.Exannneseoddsveiopmsnt Smash-staundhbdwhatyou outthedsvelopinganhryaLook
alongthelsngthd'thepodwidi usinsidsdiepodsDetethe wefuilywithyom-handlons.
handlensormicrosoope. drawing. " Whatdoyoasoe?

 

 

 

97

PAGE 2-79

    
 
 
    
   
     
 
    
  
 
 
 
 
 
  

Brassi

Is the
Is the model accurate?
Can you observe
' a stem
0 alternating
° cotyledons

receptacle

four sepals
0 six stamens

with anthers
0 one pistil
I with stigma
fam- petals

pollen grains

 

signature of evaluator

98

GERMINATION mm A...

 

            
 

S“ I) “\‘7 \\\.\‘

\‘-’

 

1. Cuttwolayersofpapctawds 2. Withapencilflebelfliebottou
tofitinthomdmhalflofe d'thepepertowelwithym
IO iOl . .

 

  
 

 

4m 0 5. Mpdridishatansndeh

shallownterinthebuefa
4. PlaoefiveFastPhntseedson two-litersodabotfleorinan-q
thetaphalfofthetoweland sotbatthebottomlfl'oflhe
mwiththebottomkmaller towelisbelow thewatu-‘ssar-
InlDot'thepetridish. face.

 

 

 

 

 

 

 

99

GERMINATION

STUDENTS’ WORKSHEET

Background
Ammbnssicaseedcmsismofmemhyommndedbyaseedmlhecmmyocmsimof
coryledons (the seed leaves),rootandshoor apical meristemandthe hypocotyioroot sun's. The
ad remains dormant until conditions are appropriate for germination. Envizonrmntal fem,
smhummpmnmmdavflhbifiryofmandoxygmanphyaafimlmlemdemmnnmgwhen
gunfinadonoccmsflhefirstsuucnuetoemergefiomtheseedooatistheradide

New'l‘erms .

apicalmeristcm Theareaofundiflersnfiatedplamnssucatthcdpofthcmotorshootfiomwhich
newccllsarise.

dormancy Acontfidonofmtedgrowthinwhichtheplant(oritsparm)doesn0tbcginm
growwithoutspedaienvironmeamlcncs. '

germination 'I'hebeginningofgrowthbyaseed.

hypocotyl-motaxis Theembryoazdsbclowtbecotyledon(s)consistingofthehypocotylandme

apicalmu'isuemoftheradiclc.

radicle Embryonicmor.

Objectives

Yonwfllobservcsomcofthcpmccssesassodawdwithseedgcrminadon.

Materials
olORCBrmds
opeuidish
opieceoffilmrpapquNo.2
oforocps ‘
ohandlcnsorsmoomicroscopcmpdonal)
°plasficsfid
0mm
°sraphpapu
ProceduresandObsemtions
Dayl
l. Placemephsdcgridmthempofapeuidishhsmanamomtofmbetweeathephmand
theplasdcwinhelpkeepthegndflat).8moothoutanywnnklesorairpocbts.
2. labcltheedgeofthefiltcrpapcr(useapcncfl.inkwiilwashout)withseedtypc,dateand
fimeofsowing,andinitialsorname(Figurel).
3. Placcthefilwrpaperoverthegndinmetopofapeuidish.Wetthepaperdiououghly.
4. Mthforoepsorfingu'splacclOseedsinarowonthetopiineofmegfidafigm'el).

 

This exercise was adapted from Some Uses of Brassica campesuis in Studies of Growth and Devel-
opment as well as Reproduca'on and Geneticrfor the Teacher by Joy Erikscn, 1361:0138! Middle
School, DcForcst, Wisconsin, 1986.

 

100

 

Figural.

Covcrwithbomomhalfofthepeu'idish.
Placemepeu-idishwithseedsatthetapataslightangleinthcwaterreservoirCfigmeZ).
Addwatcrtoadopthoncminmerescrvoir.

Placcunderfluoresccntlights.

PS9.“

 

 

 

Day2
ObmganfinadmkecorddaminTable1.1.ookforanychangcsinsecdsizc;theseedcoat
bdngsheimcmergenceofpnmmymotmmhahs,wtyledmsandyoungshmmm
withahandlcasmstctoonnuoscopc.McasmcthelengthofmmandmcmdinTabloz

Day3 . '

1. Obmethesocdlings. Whathashappenodtothehypocotyl? Recordyom'obmationsin
Table 1.

2. Whathashappcnedtotheroot? Rocordyomobsmvationsin'l‘able 1.

3. Measm'eandrocm'dtheroOtlcngthinTableZ.

Day 4.
Repeat the acfivitics for Day 3. Draw one mdling in detail in the space provided.

Table L Germination.

101

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Number of seeds placed on paper
Number of seed Number of Changes in Changes in
coats spi‘rt radicles emerged hypocotyl root
Day 2
Day 3
Day 4
Table 2. Root Length (millirneters).
Seed Number
1 2 4 5 6 7 9 10
Day 2
Day 3
Day 4

 

 

 

 

 

 

 

 

 

 

 

 

Draw one seedling in detail.

Label the hypocotyl, cotyledons. roots, root hairs, and young shoots.

 

 

 

102

D' .on

1. Dothc seeds appearto change in volume before they split? Why?

2. Whatisthefirstsuucnnethatcmgcsfiomtheseed?

3. At what point in developmentdocs chlorophyll first appear?

4. Whydidsomeseedsnotgerminate? (Ifaflyomseedsgernfinatedobservethoseofother
students.)

5. Istheprimaryfunction ofthe catyledons photosynthesis orfood storage? .

APPENDIX C

APPENDIX C

SAMPLE STUDENT CONI'3EP'1| MAPS

These maps were typed, verbatim, from.atudent maps.

81

A

(Photosynthes;

 

ator e

‘/»fl‘é enters .\
( Sunlighgm 11.5w Cotyledons

\

captures which is where is for

\z - \é

arried by

let in 02
13:7, ‘uce combines with

 

 

 

/Respiration

 

 

103

104

Ermination 1

 

Embryo

E with the right this grows

.-

 

 

 

 

 

Vascular Plants

( one group) second group

\V
( Angiospeimsp Gymnosperms

/ I

have have

( Uncovered 8%
they have /

A

Xylem amd Phloem 113%

made by

 

 

 

 

 

 

 

 

 

Cambium

 

105
[ Transpiration?
J!

Guard Cells

guard the

L

which lets in and out

L

 

 

112

106

__

L PhotosynthesE

used for

L

until

T

contain

L
carbon dioxi- -
quLls

@N) stored ..__——? Starch

\
and 02 /

Waste equals

-
L/
609

107

combines with

/?

088
equals produces “’9. Waste is

Energy

 

7

iVascualr Plant” 4? contain—- Al Xylem &

 

Phloem

L‘ligfisiiiiiip» (giggosperms toTEiin
L

produce produce Cambium

flaw'ers &
Covered Seeds @ered 3%

 

 

 

108
lGerminationLaz-ighta we eed Develop
I enough—3

- contains ‘4

\Transpiration -— happens when-‘9.- regulate- Amount of
~ 320

going through

¢

/

on surface of

\L

 

 

 

 

 

109
u
stored

¢

Photosynthesis is for/a Food Storage
+ I l/ N
W \l/
captured by @EeaQ
1‘1” L L
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J“ '/ 5
makes {‘13} Ikxxi
‘1’ \I

carried by

let outL/

 

 

 

 

 

L

let in

L
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Q,

produce

110 _

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Eranspiratifl
‘57
m

L

guard cells regulate

_

St.O M'ta

~L

Which let in

._‘

Fewer?
vb

the

4/

Seeds

akr’l”,z”’IWith£ t e yrigh\
Moisture

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1;

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111

Escular

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4/

W...

 

 

 

are have

1

ficovered seeds
seen“; \\\\\‘~\~\j; ¥://///”,,r”””
theijave
612R. Phloem Tissues )

made by the

L

Cambium

 

 

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EesLiratjE

adds

I

with

L5///equals

1 1 2
[P'hotosynthes is 2

./

captured by

( Chlorphyll >\

all equals

 

Waste

9
‘z

0
N
H
H
3

called

9e

 

 

Escular L
\
plants have

4:

Xylem

tubes and

J/

Phloem

ix

tubes also have

i I

produce produce

‘1’ \fi
@ @ed seeds 3

 

 

. 113
Tiranspiration]
I

has

Guard Cells

1

which regulate the opening and closing of the

< Strmmrta.)

~11

which regulates

s1;

@erminatiE
L

with the right

L

d

.3
1L“

 

L

d
(02)
it will create growth called

from the

114

 

 

 

 

L1
Wsynthesis L
/
v
make
\L 11
the CW
‘
1
gets in the
A!
M in the
1......
J
when food is stored it is
called I l]

a 9

food goes down the

._‘ 115 __
[PespiratiSn]
.L
{z

is used for

 

Ener

 

Glucose

iflastr

‘

R

6‘5“ {—3

9

 

[Germination]

E.

9
m

E
*3

I;

is the young plant at needs the right

aw

 

_ 1 16
[Vascular Plantg

/ A:
are ®
./
W food goes up the plant
.1, 4/
..

Jx

Uncover® food goes down the plant

4/

L

have

4/
@ered @

 

 

 

 

 

Eanspiratia
f 4/

Stomata

§
$6-

is the

Guard Cells

6-

@656

to lose too much or too little

APPENDIX D

APPENDIX D

INSTRUCTOR'S CONCEPT MAP

 

 

 

 

 

117

118

    

 

 

 

 

               

 

 

 

 

 

 

_ @1111
+0.11 ®Lo/ 1....
.115

 

[ mam—l

 

1111...
L/@11\.x@x_/@-..

L1 .11....xole1
111/9:11.111

 

 

 

 

 

 

 

120

 

 

 

 

 

APPENDD§ E

APPENDIX E

CENTRAL QUESTION

HOW ARE PLANTS, AS PRODUCERS, FUNDAMENTALLY DIFFERENT, YET

SIMILAR TO CONSUMERS SUCH AS HUMANS AND OTHER ANIMALS?

People eat food of various kinds, drink water and breathe
air; Plants take in minerals, water, and air. Plants do not
rely on multiple sources for their food energy and they do
not use water and air in the same way consumers do. Consumers
ingest their food. Plants make their own food through
photosynthesis .

Consumers take in oxygen and release carbon dioxide. Plants
take in carbon dioxide and release oxygen. Plants and
consumers both need oxygen to carry on respiration.

Plants and consumers both take in water to "recover” and
"rejuvinate" but water is taken apart by plants and used in
the food-making process .

Plants an animals are composed entirely of. cells and
specialized cells are needed by plants and animals to do
specific jobs.P1ants and consumers store food.

Plants and consumers go through various stages in their life

cycle as they grow and develop .

121

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