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Teaching Evolution Concepts using a Hands-On Approach

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TEACHING EVOLUTION CONCEPTS USING A HANDS-ON APPROACH
By

Amanda Jane Whitfield

A THESIS

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

MASTER OF SCIENCE
Interdepartmental Biological Sciences

2008

ABSTRACT
TEACHING EVOLUTION CONCEPTS USING A HANDS-ON APPROACH
By

Amanda Jane Whitfield

Teaching evolution can be challenging because of the many misconceptions
students hold about the theory and due to students’ personal and religious beliefs.
However, evolution is now required in the Michigan biology curriculum and can no
longer be avoided. This thesis focuses on incorporating hands-on activities in an
evolution unit designed for an introductory high school biology course to encourage
student learning of evolutionary concepts. The labs and activities were designed to
address student misconceptions and increase student knowledge of the theory of
evolution.

A wide variety of labs and activities were implemented during the evolution unit
with a high rate of success. The students improved their scores on the post-test, as
compared to the pre-test. Also, the attitudes and opinions regarding evolution changed for
the students when the pre-survey and post-survey were compared. Overall, the hands-on

activities were successful and more meaningful for student learning than lectures alone.

ACKNOWLEDGEMENTS

I would like to express my gratitude to the faculty and staff of the Division of
Science and Math Education at Michigan State University for encouraging me,
supporting me, and teaching me throughout the entire process of finishing my Master’s
Degree. A special thanks to Dr. Merle Heidemann for all of her assistance, knowledge,

and guidance. I would also like to thank my friends and family for their support as well.

iii

TABLE OF CONTENTS

LIST OF TABLES ............................................................................................................ v
LIST OF FIGURES .......................................................................................................... iv
Introduction ......................................................................................................................... 1
The Science Behind Evolution ........................................................................................... 4
Theoretical Framework for Teaching Evolution .............................................................. 11
What is Science? ........................................................................................................... 11
Why Teach Evolution? ................................................................................................. 13
Teaching Evolution ....................................................................................................... 18
The Controversy ............................................................................................................ 19
Demographics ................................................................................................................... 23
Implementation ................................................................................................................. 25
Overview and Summary of Activities ........................................................................... 26
Data and Analysis ............................................................................................................. 33
Pro-Survey ..................................................................................................................... 34
Post-Survey ................................................................................................................... 37
Post-Survey Questions .................................................................................................. 39
Pre-Test ......................................................................................................................... 41
Post-Test ....................................................................................................................... 42
Paired T-Tests ............................................................................................................... 44
Labs and Activities ....................................................................................................... 45
Multiple Choice Test ..................................................................................................... 50
Conclusions ....................................................................................................................... 5 1
Survey Results .............................................................................................................. 51
Discussion of Labs and Activities ................................................................................. 54
Pro-Test and Post-Test .................................................................................................. 55
Summary ....................................................................................................................... 56
APPENDICES .................................................................................................................. 58
APPENDIX 1: Michigan High School Content Expectations for Evolution ................ 59
APPENDIX 11: Activities and Labs .............................................................................. 62
APPENDIX III: Assessments and Rubrics ................................................................. 117
BIBLIOGRAPHY ........................................................................................................... 129

iv

LIST OF TABLES

Table 1: Sequence of Events for the Evolution Unit ....................................................... 25
Table 2: Student Descriptions .......................................................................................... 33
Table 3: P-values for Paired T-Tests of Pro-Test and Post-Test ...................................... 45

Figure 1:
Figure 2:
Figure 3:
Figure 4:
Figure 5:
Figure 6:
Figure 7:

Figure 8:

LIST OF FIGURES

Pre-Survey Mode for the Fifteen Opinion Statements ..................................... 34
Pre-Survey Points per Question for the Nature of Science .............................. 36
Pre-Survey and Post-Survey Mode for the Fifieen Opinion Statements .......... 38
Post-Survey Points per Question on the Nature of Science ............................. 39
Pre-Test Points per Question ............................................................................ 41
Post-Test Points per Question .......................................................................... 42
Mean Scores for Pre-Test and Post-Test .......................................................... 44
Number of Correct Answers for Multiple Choice Questions ........................... 50

Introduction

With the advent and implementation of Michigan’s new state standards, the
biology curriculum has become more intense and demanding. Any topic in biology would
have been appropriate to research in light of the new expectations. Photosynthesis and
cellular respiration are complicated topics to teach and students often end the unit without
a clear understanding of the processes. Cellular division can also pose problems for
student learning, and the human body systems are not covered in my biology classes
because there is not sufficient time to teach everything. After reviewing my curriculum, I
found that evolution is my least developed unit and decided to focus my research at
Michigan State University on the topic. Prior to this study, the evolution unit was rushed,
and dominated by lectures and worksheets. It lacked the labs and activities that the other
units in the biology curriculum contained. I observed students were often bored with the
topic long before it was over because they were not actively engaged in any activities.

Traditionally, in my curriculum, evolution is taught at the end of the semester
long course in biology. The unit typically follows genetics and classification, and should
tie all of the concepts previously learned together. Understanding evolution requires
knowledge of DNA, mutations, sexual reproduction, ecology, and cellular processes, all
of which are addressed in previous units during the semester. Ending the semester with
evolution helps students review and apply what they have learned earlier in the semester,
while engaging in new concepts concurrently. With new activities that actively involve
the learners, my goal is for students to have a better overall understanding of evolution
and how it unites all of biology. The problem investigated by this study centered on how

to improve student understanding of evolution using new labs and activities.

Students carry many preconceived notions and misconceptions with them to the
classroom concerning evolution. Based on the curriculum from the middle school,
evolution is not taught extensively prior to high school. The students can give examples
of how organisms adapt to their environment, but beyond a limited set of examples for
adaptations, they have no understanding of evolution or its mechanisms. An overall
awareness of misconceptions and the lack of prior knowledge pertaining to the theory of
evolution also motivated me to choose evolution as a research topic.

In addition to student misconceptions, the new expectations required by the State
of Michigan also lead me to choose evolution. In the past, evolution was not emphasized
extensively in the State curriculum. With the application of the new expectations,
evolution is a whole unit, required and expected to be taught. As evolution is addressed
on the Michigan Merit Exam, I want my students to be fully prepared for any question
concerning evolution. Lectures and worksheets alone will not give the students the long-
term recall of the information necessary for success on the standardized tests.

The majority of my research was devoted to finding and developing new activities
that addressed the various aspects of evolution. I wanted the activities to draw the
students into the topic and allow them to make their own observations, hypothesis, and
conclusions, forcing the students to think on their own, and not just regurgitate facts.
Student misconceptions cannot be changed with lectures alone, and I focused on
activities that would help them see that evolution is not just scientist’s best theory, but
something they can become engaged in and observe. Since many of the processes
involved in evolution take millions of years to occur, the skepticism of the students is

justified. However, with the use of simulations and activities, the students can actively

participate in the processes and concepts of evolution. With active involvement in the
learning process for evolution, the students will have a more complete understanding of
the topic.

The thesis focuses on my evolution unit and the incorporation of new labs and
activities meant to aid student learning and challenge misconceptions. Assessments were
utilized prior to the unit beginning and following the end of the unit to gauge student
learning and opinions. Overall, the evolution unit underwent extensive changes as

compared to how the unit was taught in the past.

The Science Behind Evolution

Evolutionary theory addresses the relatedness of organisms by explaining that the
millions of species on earth are related by descent to common ancestors. As organisms
compete for limited resources, some traits provide an advantage for survival. Those traits
that are heritable are passed from one generation to the next. As differences continue to
occur in a population and accumulate, populations of organisms diverge from their
ancestors. (National Academy of Science, 1998) The divergence from the earliest
organisms has lead to the diversity of life today. Even though humans, bacteria, and
salarnanders seem to defy comparison, they all share some of the characteristics of their
common ancestors. Diverse organisms have descended from common ancestors,
accounting for the similarities shared by species. Biology is the story of life, but
evolution is the story of biology and the relatedness of all living things. (Alters and
Alters, 2001)

The diversity of life can also be explained by evolution. When members of a
population possess measurable difference in heritable traits that favor survival, these
adaptive traits are passed on to offspring. As populations inhabit different niches, the
individuals with more successful traits increase in number and the nature of each
population changes. Isolating mechanisms vary, but the overall result is the same.
Populations split from common ancestral populations, and differences accumulate,
allowing organisms to occupy new ecological niches. (Alters and Alters, 2001)

The earth is billions of years old, not 6,000 to 10,000 years old as once previously
thought. Life did not appear on Earth until 3.5 billion years ago. In the time since then,

millions of species have lived on Earth, all sharing a common ancestor in the distant past.

The theory of evolution provides a scientific explanation for the history of life on Earth,
and also explains both the diversity of life and why there are similarities that exist
between different species. Evidence for evolution and common ancestors may be
observed in the fossil record, homologous structures, embryonic development, and in
molecular biology.

Fossils provide a snapshot of organisms in the past. The layered deposits of fossils
in rocks reveal the history of life in a particular region. By studying fossils from
sequential layers of rock, a researcher could view how living organisms are linked to a
common ancestor.

Living organisms also provide evidence for evolution. The limbs of vertebrates
differ in form and function, but they are all constructed from the same basic bones.
Homologous structures develop fi'om the same embryonic tissues, like the bones of the
limbs of vertebrates. Even though they may be wings, legs, or flippers, the bones all
develop the same way in the embryo. Evidence that four-limbed organisms with
backbones descended with modification from a common ancestor is provided by
homologous structures. Vestigial organs are traces of homologous structures that serve
little or no purpose. For example, skinks have tiny legs that no longer function in
walking, and humans have an appendix that no longer plays a role in digestion. Even
though these organs no longer serve a purpose for the organism, vestigial organs may not
disappear because they have no negative affect on the organism’s ability to survive and
reproduce. Therefore, natural selection has not totally eliminated the organ.

In addition to fossils and homologous structures, DNA gene sequencing provides

evidence for evolution. Organisms that seem to have fewer similarities may share large

sections of gene sequences. In the past, morphological characteristics were used to
classify organisms. However, classification based on physical traits is inadequate because
organisms that look alike may have little common heritage. For instance, a dolphin looks
like a fish, but it really is a mammal. Now, with the advent of gene sequencing and
development, organisms can be grouped together based on similarities in their genomes.
DNA is providing additional evidence for evolution that is irrefutable.

In simple terms, the theory of evolution states that groups of organisms change
over time. Charles Darwin, the grandfather of current evolutionary theory, published his
theory in 1859 in the book On the Origin of Species, after years of traveling and
collecting observations on the differences among individuals of the same species.
Although information on genetics and DNA were not available during Darwin’s time, his
observations lead to the same conclusions scientists confirm today. We now know the
sources for changes in a species include sexual reproduction, as a result of meiosis, and
mutations. As a result of these two processes, variation exists within a species. Natural
variation is defined as the differences among individuals of a species. The differences
that exist in crops and livestock have been exploited for years, as farmers try to grow the
best crops, or raise the biggest animals for food, a process termed artificial selection. In
artificial selection, nature provides the variation, and humans select the most useful
variations to utilize and breed, in the hopes that those traits will move from one
generation to the next. Farmers want the best fruits or livestock, so they choose what
organisms will pass their genes on to the next generation.

Natural selection is not so different from artificial selection. Instead of humans

deciding what traits are passed on, nature chooses. In nature, organisms must compete

with each other for a limited amount of resources in a struggle for existence. Most
organisms produce many offspring, but not all of the young survive as a result of
competition, disease, and predation. Therefore, the high production of offspring increases
the chance of some of the young surviving to reproduce. The organisms that are stronger,
faster, or better adapted to the environment are more likely to survive and pass on their
traits. Fitness is the ability of an individual to survive and reproduce. Adaptations, like
speed, camouflage, mimicry, and toxins, increase an organism’s fitness. An adaptation is
any inherited characteristic that increases an organism’s chance of survival. Successfiil
adaptations cause an organism to be better suited to their environment and increase the
likelihood the organism will survive and reproduce.

Survival of the fittest is the idea that individuals that are better suited to their
environment, or more fit, will survive to reproduce more successfully than organisms that
are less fit. Natural selection is the process that determines which organisms are the most
fit. Over time, natural selection results in changes in the inherited characteristics of a
population. These changes increase a populations’ fitness in the environment, and the
changes will increase in frequency in the overall species over time.

Organisms today look different than they did in the past, as evidenced by the
fossil record. Over long periods of time, natural selection produces organisms that have
different structures, niches, or habitats. Each living species has descended from other
species with modifications. This is known as the principle of descent with modification,
and the principle implies that all living organisms are related to each other through a

common ancestor and common ancestors of separate groups.

In order for a trait to be passed fi'om a parent to the offspring, the allele for the
trait must be present in gametes, if sexual reproduction is used. When sexual
reproduction is utilized, mutations that occur in somatic cells can not be passed on to
Offspring, even if the mutation increases fitness. Gene pools are the combined genetic
information of all the members of a particular population, and they constitute all of the
alleles that can be inherited by future offspring. The relative frequency of an allele is the
number of times the allele occurs in a gene pool compared to other alleles. Sexual
reproduction is the main source of variation within a population. However, sexual
reproduction does not change the relative frequency of alleles in a population because the
genes are just shuffled in the formation of gametes, they are not eliminated or changed by
mutations.

The number of phenotypes produced for a given trait depends on the number of
genes that control the trait. Single-gene traits only produce two phenotypes. An
individual either has the trait or they do not. Natural selection on single gene traits can
lead to changes in allele frequencies and to evolution. Organisms of a certain color may
produce fewer offspring than organisms of another color, resulting in change in the
population. Polygenic traits are controlled by more than one gene and they show more
variation than single-gene traits. When graphed as a distribution, polygenic traits
typically form a bell curve.

Natural selection can affect the distributions of polygenic phenotypes in three
ways. In directional selection, individuals at one end of the bell curve have higher fitness
than individuals in the middle or at the other end. Evolution causes an increase in the

number of individuals with the trait at one end of the curve, and the average phenotype

shifts. Stabilizing selection is the result of the average phenotype having a higher fitness,
and the bell curve pinches in the middle because the phenotypes at the ends of the curve
are less fit. Finally, in disruptive selection, both ends of the bell curve have a higher
fitness than the average phenotype. Disruptive selection can result in two distinct
phenotypes, as long as natural selection is strong enough and acts long enough.

If a population does not experience change, then evolution does not occur. The
Hardy-Weinberg principle defines this further by stating that allele fi'equencies will
remain constant unless one or more factors cause the frequencies to change. When there
is no change in allele fi'equencies, a population has attained genetic equilibrium. In order
to maintain genetic equilibrium, there must be random mating in a population, the
population must be large in numbers, there can be no immigration or emigration, no
mutations may occur, and natural selection cannot happen. If one or more of these
conditions is not met, then genetic equilibrium is disrupted and evolution occurs.

Speciation is the process that leads to the formation of a new species. The formal
definition of a species is a group of organisms that can breed and produce fertile
offspring. When a new species evolves, populations become reproductively isolated from
each other. Reproductive isolation occurs when two populations can no longer produce
fertile offspring, and two separate gene pools exist. In behavioral isolation, two
populations are capable of interbreeding, but have difference in courtship rituals or other
behaviors that isolate the populations reproductively. Two populations can be separated
by geographic barriers, and geographic isolation can result. Populations living on either
side of a river may not reproduce any longer as a result of the barrier, and natural

selection will work on each group separately. It is important to note that geographic

barriers do not always result in Speciation. If two separated populations can still
interbreed, then they remain a single species. Reproductive isolation can also result from
temporal isolation, in which two or more species reproduce at different times.

Overall, evolution is a complex theory that helps to explain the diversity of life
and the similarities that all organisms share. The mechanisms of evolution depend on
competition and natural selection and result in changes in groups of organisms over time.
As changes accumulate in a group of organisms, the species becomes better adapted for

survival, and may result in a new species.

10

Theoretical Framework for Teaching Evolution
What is Science?

"The best science teaching reveals not just the science of nature, but also the
nature of science.” (Pennock, 2005) Science is not just facts or theories; it is a dynamic,
inquiry-based method of looking at the natural world to understand how it operates.
Students must move past rote memorization of facts and vocabulary to the application
and actively participate in the process of science. Today’s world is the most scientific
society that has ever existed, and failing to provide students with an understanding of the
power and process of science is a disservice. The lack of understanding of how science
operates is a contributing factor to those who fail to accept evolutionary theory. (Forbes,
2007)

The National Academy of Sciences has defined the characteristics of science. In
summary of their findings: Science must be guided by natural law, including the laws of
physics, geology, chemistry and biology; science must be testable against the natural
world; conclusions in science are tentative pending additional information; conclusions
are potentially falsifiable; science asks a question and then seeks answers to those
questions. (National Academy of Sciences, 1998) Science is not guesswork; it is based on
evidence and relies on the assumption that anything that can be observed or measured can
be investigated by science. (N STA, 1997) Science differentiates itself from philosophy
and theology; two disciplines that attempt to incorporate nature and human existence,
because science is based on empirical research and explains the world using only natural

explanations. (Forbes, 2007)

ll

The nature of science reveals that science is not the same as common sense.
Science is based on data and observations, and as observations and evidence accumulate
and change, so does science. Science statements are not the final truth, but as the
evidence accumulates over time, the statements become increasingly more accepted.
Finally, science is based on the work of individuals, but requires the collaboration and
reinforcement of the scientific community. Darwin’s original theory would not hold up
without the significant amount of evidence that now exists, as a result of other scientists
working to reaffirm his original theory. (National Academy of Sciences, 1998)

According to the National Science Education Standards (1998), scientific literacy
implies that a person can ask, find, or determine answers to questions derived from
curiosity about everyday experiences. Additionally, scientific literacy necessitates that a
person has the ability to describe, explain, and predict natural phenomenon. Literate
individuals can read scientific articles with understanding and engage in social
conversation about the validity of the conclusions. Also, they can evaluate the quality of
scientific information on the basis of its source and the methods used to generate the
article. (National Science Education Standards, 1998) A scientifically literate individual
is capable of forming a conclusion, based on the data and source, and refuses to accept
everything presented in the popular media. According to a survey completed on scientific
literacy in the United States, fewer than 7% of adults, 22% of college graduates, and 26%
of individuals with a graduate degree are scientifically literate. (Miller, 1998)

In order to increase scientific literacy for evolution, some common words must be
clearly defined. A theory, in every day is speech is often utilized to mean a guess or

hunch, but this is what scientists would call a hypothesis, not a theory. Contrary to

12

common use, theories are the most important scientific explanations of natural
phenomenon and are not guesswork. The National Academy of Sciences (1998) defines a
theory as “. . .a well-substantiated explanation of some aspect of the natural world that can
incorporate facts, laws, inferences, and tested hypotheses.” Any scientific theory is based
on evidence, and is not a guess. Scientific facts are defined as “. . .an observation that has
been repeatedly confirmed,” by the Academy. Finally, the Academy defines a law as “A
descriptive generalization about how some aspect of the natural world behaves under
stated circumstances.” Misconceptions concerning the definitions of facts, laws, and
theories can impede scientific literacy and the understanding of evolution.
Why Teach Evolution?
“When you combine the lack of emphasis on evolution in kindergarten
through 12th grade, with the immense popularity of creationism among the
public, and the industry discrediting evolution, it’s easy to see why half of
the population believes humans were created 10,000 years ago and lived
with dinosaurs. It is by far the biggest failure of science education fi‘om
top to bottom.”
— Randy Moore, Editor (1999), The American Biology Teacher
Many of the how and why questions of science, that often ignite the curiosity of
students can only be answered by evolutionary concepts. For example, why are there so
many unique species, and where did life come from? Scientists agree that students can
not attain a well-rounded background in science without learning evolution. (Alters and
Alters, 2001) Most famously, Dobzhansky said, “Nothing in biology makes sense except
in the light of evolution.” (1973) Evolution is the unifying theory that connects all of
biology, and incorporates many of the other sciences. Scientific disciplines with a

historical component, like astronomy, geology, biology, and anthropology, cannot be

taught thoroughly if evolution is not incorporated. (N STA, 1997) Overall, evolution is a

13

unifying theme among the sciences, and provides students with a fi'amework to
understand the natural world. (Alters and Alters, 2001)

Where did life on earth originate? Why do organisms across species have so many
striking similarities? Despite sharing common characteristics, why are there so many
different types of organisms? The diversity of life, the history of life, and the similarities
between living organisms can only be addressed scientifically by evolution. Biology can
effectively explain how organisms reproduce, the mechanisms and processes of cellular
respiration, and how organisms work overall, but evolution is the only theory that can
explain why. Although scientists continue to discuss and disagree on some of the details
governing natural selection, the scientific consensus is that evolution has happened in the
past, and is occurring today. Evolutionary theory is the best and only scientific
explanation for the unity and diversification of life on earth. (MSTA, 2007)

Evolution can also help explain the changes in the planet’s physical environment.
The processes of photosynthesis and cellular respiration account for the differences in the
planet’s atmosphere since the beginning of earth. Photosynthesis has created an
atmosphere rich in oxygen that supports the majority of living organisms. Populations of
organisms also impact weather, climate, and the movement of water from the atmosphere
to the land and the oceans. Water moves through the living systems of plants and back
into the atmosphere, playing an important role in the water cycle. Finally, plants and
microorganisms can absorb or emit greenhouse gasses that control global temperatures.
(National Academy of Sciences, 1998)

Structure and function are inseparable from each other in living organisms, but

why are they so closely related? Once again, evolution provides an answer. Organisms

l4

with an anatomical feature that is better adapted to a certain function are more likely to
live to reproductive age than organisms with structures that do not function as well.
Structures that fit a function are adaptations that accumulate in a population over time.
For instance, bird beaks are shaped in a way that allows birds to eat a particular type of
food. Structurally, beaks serve a specific function, and beaks that increase survival will
increase in a population over time. (Alters and Alters, 2001)

Evolution contributes to the society we live in today. The theory helps explain
why some antibiotics are no longer effective because the microorganisms have evolved
resistance over time. (National Academy of Sciences, 1998) Understanding evolution
also aids in understanding the frequency of genetic diseases. For instance, sickle cell
anemia is more prevalent in Afiican Americans because individuals with the disorder are
resistant to malaria. Even though sickle cell anemia eventually leads to death, the gene
provides an adaptive advantage in the resistance to malaria, another potentially fatal
disease. (Alters and Alters, 2001)

Overall, evolution is a unifying concept that links science disciplines together. It
is critical that students understand the mechanisms involved in evolution so that they can
understand the world around them, and answer some of the why questions that they will
encounter in life.

Common Misconceptions

Students enter any science classroom with prior knowledge and misconceptions
concerning various topics. Teachers provide learning experiences that aid students in
generating links between relevant information and what they already know. (Alters and

Alters, 2001) Misconceptions are difficult to change, and students have many

15

misconceptions concerning evolution. To challenge and change misconceptions requires
an extended period of time, and students must be exposed to new concepts continuously
in order to reach a more complete understanding.

One obstacle that has to be overcome when teaching evolution is the age of the
earth because students have no concept of the long expanses of time between the
beginning of earth and the appearance of life. Many students believe that the earth is very
young, as compared to billions of years old. The story of creation and religious beliefs
often cater to this misconception. In addition, there are misconceptions concerning the
origin of life. Some students believe that life appeared suddenly, and the types of
organisms have not changed since the creation of Earth. Despite the evidence found in
the fossil record, many believe that humans lived in the time of dinosaurs. (N STA, 1997)

According to a study conducted by Anderson and Bishop that consisted of non-
major introductory biology students, students thought that the environment causes traits
to change over time. They failed to acknowledge the importance of genetic variation and
the role mutations and sexual reproduction play in causing the frequency of traits to
change over time. These students felt that the organisms changed in response to
environmental demands, and they lost the idea that the environment affects the survival
of traits after their appearance in a population. The study also found another common
misconception in that students did not view genetic variation as an important mechanism
for evolution. Variation is essential for natural selection to act upon. A common mistake
is for students to think that evolution acts on a species as a whole, but it is the variation
among individuals that causes a population to change over time, as new traits establish

themselves in a population. (Bishop and Anderson, 1990)

16

“Evolution is just a theory.” Many students use this statement as an argument
against evolution. However, this misconception is the result of confusion in definitions
for a theory. Other words that lead to confusion and reinforce misconceptions include
adaptation and fitness. In every day language, an adaptation refers to the ability to change
a physical, behavioral, or other attribute in response to an environmental condition. In the
context of science, an adaptation is a change in a population of organisms that occurs as
the result of chance mutations or sexual reproduction. Only traits that are heritable and
increase the chance of survival and reproduction are considered adaptations. Finally, in
daily language, fitness refers to the health of an individual. In the context of evolution,
fitness is the ability of an organism to survive to reproduce and produce viable offspring.
(Alters and Alters, 2001) Once again, scientific literacy proves to be essential for the
understanding of evolution and the elimination of misconceptions.

Evidence for evolution exists in the fossil record, but many people argue that the
fossil record is incomplete, lacking transitional fossils. Therefore, many conclude that
there is a lack of evidence for evolution, and consider the theory void. This may have
been true during Darwin’s time, but the fossil record is much more complete now, with
the discovery of new fossils occurring every day. A common misconception in science is
that science can only confirm events if they have been observed happening. Since the
evolution of dolphins was not observed, their evolutionary descent cannot be proven. To
find the evolutionary pathway of a dolphin, the fossil record provides sufficient evidence,
even though dolphins evolved long ago, and scientists did not see it happening in real

time. (Forbes, 2007)

17

The theory of evolution is thought to state that humans evolved fi'om monkeys.
Many students believe that this statement is true, and that is often all they know of
evolution. However, the theory does not teach that humans descended fi'om monkeys.
Instead, it states that both humans and monkeys share a common ancestor. Many argue
that if humans descended from monkeys, then monkeys should no longer exist. This
common error is the result of not understanding that new species evolve by splitting from
an established species. The established species does not disappear. A new species may
appear as the result of isolation mechanisms and as sufficient differences accumulate in
the populations, the two groups are different enough to result in two species. (Rennie,
2002)

Finally, some individuals feel that science works to disprove God. Since the
presence or absence of a god cannot be tested empirically, it falls outside the realm of
science. Science can only address issues that can be tested, and those that cannot be
tested can only be explored through philosophy and theology. Science attempts to explain
the world using only natural causation, and is based solely on empirical investigations.
Therefore, one does not believe in science, but rather, it is more appropriate to say that
one accepts the evidence for a scientific theory, like evolution. (Forbes, 2007)

Teaching Evolution

Lectures alone are not sufficient for students to leave a class with an
understanding of evolution. Since lectures often promote memorization and do not allow
students to apply the concepts of evolution, they are ineffective if not supplemented with
activities. Listening to a lecture does not cause enough conflict in a student’s mind to

challenge his misconceptions, and the student walks away with the same misconceptions

18

he held prior to the class. It is imperative that students are exposed to problem solving,
hands-on activities, and simulations involving the concepts of evolution. If
misconceptions are not addressed through activities, then they will not be challenged, and
will not change. (Alters and Alters, 2001)

The concepts of evolution are often abstract and difficult for students to grasp
without concrete examples and applications. (ibid) Labs and hands-on activities provide
students with the opportunity to visualize and actively participate in the tenants of
evolution. Rote memorization is not enough to address misconceptions and change points
of view.

Definitions and facts are important and can be presented in a variety of ways, but
there are many experiences, like hands-on activities, that greatly enhance learning.
(Moore et a1, 2001) In a study conducted by McManus, Dunn, and Denig in 2003 on the
effects of learning through lectures versus through hands-on activities, the study found
that the more students were involved in tactual and kinesthetic resources, or hands-on
activities, the more their science and achievement and attitude scores increased.
(McManus, Dunn, and Denig, 2003) In other words, hands-on activities increase student
understanding and performance for science classes. It is imperative that students are able
to do science and understand the characteristics of science. (Leonard, Speziale, and
Penick, 2001) In order to do science, the students must be engaged in hands-on activities
and labs that will lead to an understanding of the characteristics of science.

The Controversy
Opponents to teaching evolution in the classroom argue that creationism and

intelligent design should be included in the science curriculum if evolution is taught as

19

well. According to William Jennings Bryan, the prosecutor in the Scopes Trial, as quoted
by Randy Moore, “all the ills from which America suffers can be traced back to the
teaching of evolution.” (Moore, 2005) Bryan also stated, “If the Bible and microscope do
not agree, the microscope is wrong,” as quoted by Randy Moore. (ibid) Despite the
overwhelming scientific evidence supporting evolution, theology and philosophy often
intrude on the teaching of evolution. A personal conflict exists for many when it comes to
accepting the concepts of evolution. Many teachers exclude evolution from the biology
curriculum because they want to avoid conflict with parents and students. According to a
survey conducted by the NSTA, 31% of teachers indicated that they feel pressured to
include creationism, intelligent design, or other non-scientific alternatives to evolution in
their curriculum. Most of this pressure originates from parents and students, not school
administrators. (N STA Express, 2005)

According to a statement by the Michigan Science Teachers Association, teachers
should only teach evolutionary theory as the explanation of the development and
diversification of life on earth. Additionally, non-scientific alternatives should be omitted
from the curriculum as they offer alternatives to students that are false scientific
alternatives. Similarly, the National Science Teachers Association supports the teaching
of evolution because if evolution is omitted, students will not reach the level of scientific
literacy necessary to participate in society. They further propose that teaching evolution
has been deemphasized in science classrooms as the result of intimidation of science
teachers, the general public’s misunderstanding of the theory, and over a century of

controversy. (MSTA, 2007)

20

The overwhelming majority of scientists reject the concept of intelligent design.
Proponents of intelligent design argue that the evidence for evolution is incomplete, and
the only explanation to fill in the gaps is an intelligent designer. (Brumfiel, 2005) Since
intelligent design does not rely directly on biblical sources, many Christian groups
support the alternative explanation in an effort to move creationism back into the
classroom. (Ibid) There are many political goals attached to intelligent design that cause
scientists to outright reject the alternative. (Ibid) The National Science Education
Standards notes that, “explanations of how the natural world changes based on myths,
personal beliefs, religious values, mystical inspiration, superstition, or authority may be
personally useful, and socially relevant, but they are not scientific.” (1996)

Since its conception, evolution has been controversial at it challenges an
anthropocentric view of life. Several court cases have upheld the teaching of evolution,
and the elimination of creationism from the science classroom. The First Amendment
requires that public institutions, like schools, be religiously neutral. Therefore, the
inclusion of creation science, which asserts a specific religious view, cannot be supported
in public schools. In Mclean v. Arkansas Board of Education, the judge ruled that
“creation science” did not qualify as a scientific theory. The decision by the Supreme
Court in Edwards v. Aguillard found that creation science was an inherently religious
idea, and teaching it in public schools would be unconstitutional.

In the most recent court case, Kitmiller vs. Dover Area School District, Judge
John Jones found that intelligent design should not be taught as a reasonable scientific
alternative to evolution. Even though the theory of evolution is not perfect, it “should not

be used as a pretext to thrust an untestable alternative hypothesis grounded in religion

21

into the science classroom or to misrepresent well-established scientific propositions.”
(Humes, 2005) The Dover case concluded that intelligent design is not an alternative to
evolution, and should not be included in any high school science curriculum. Many
additional court cases have upheld including evolution in a science curriculum, while

omitting creation science and intelligent design.

22

Demographics

I teach at Vestaburg High School, located in a small, rural community in
Montcalm County. Vestaburg’s population is 3,029, and 85% of the families own their
own home, while the other 15% rent. For the township, the median household income is
$33,641, as compared to the State of Michigan median income of $43,880. The
percentage of adults living in district with at least a high school diploma is 83.7%, and
10.2% of adults have a bachelor’s degree or higher. Approximately 11% of the students
in Vestaburg come from single parent homes. (School Matters, 2006)

There are 254 students that attend the high school, and 91% of the students are
Caucasian. Very few minority students attend Vestaburg, and social groups are often
based on socioeconomic status, as opposed to race. The community is tied to agriculture,
and is suffering due to the economy. The percent of students eligible for fi'ee lunches is
73%, and another 26% are eligible for reduced lunch. (Public School Review, 2004)
Despite economic disadvantages and atypical homes, the students at Vestaburg
consistently score higher on standardized tests than the state averages. US. News and
World Report recently recognized Vestaburg High School as a Bronze Medal school.
(2008)

Sixteen teachers work at the high school, and the average class size is 16 students.
The science department has two teachers, and I am the only person to teach the life
sciences. Biology is taught as a semester long class using block scheduling, with 80
minute periods. The majority of the students in biology are sophomores that have taken
earth science as freshman. Occasionally, juniors and seniors are required to take biology

because of scheduling issues. Special education students account for 13% of the high

23

school student population are included in the general education classes with
accommodations and the assistance of the special education teacher. The biology class
included in this study had 26 students, with two of the students having special needs and
accommodations, and one minority student.

The majority of students at Vestaburg are involved in extracurricular activities,
including sports and clubs. Those who are not involved often have jobs outside of school,
or they are required to take care of younger siblings. Many of the students are actively
involved in the churches in the area. They hold strong religious beliefs, and the majority
of the students participate in youth groups and bible studies. Some of the students also
form groups at school to discuss and share their beliefs during lunch and prior to the start

of the school day.

24

Implementation

One month prior to the beginning of the unit, parent permission slips to participate
in the research were sent home. All of the students returned their permission slips, but I
was not aware of which students were allowed to participate until after the completion of
the evolution unit, in order to help reduce bias in the data collection and analysis. I began
the unit with a pre-unit survey and pre-test of evolution to reveal student misconceptions
and prior knowledge concerning evolution. Following the survey and pro-test, the unit
began in earnest. Below is a sequence of events followed for the evolution curricultun.
The majority of the material used in the evolution unit was developed during the research
period of the summer of 2007, and included many new labs and activities that provided
students with more hands-on opportunities and the ability to apply the concepts of
evolution. I did not change the pre-existing notes or multiple choice test but chose to
supplement those materials with activities.

Table 1: Sequence of Events for the Evolution Unit

 

Day State Objectives Addressed Activities
(Appendix I)
Day 1 B5.1A, BS. 1B, B5. 1c, BS.ld, Conclusion of Classification- Unit Test

B5.1e, B5.1f, 35.1 g, B5.2a, Implementation of the Pre-Unit Survey and

 

 

 

 

 

 

 

B5.2b, BS.3A, B5.3B, Pre-test
B5.3C, B5.3d, B5.3e, BS.3f
Day 2 B5.1c Timeline of the History of Life on Earth“
Day 3 B4.3c Giraffe Simulation“
A 19th Century Journey
Human Variation Lab
Day 4 B4.3c Adaptations of the Human Hand
BS.3e When Milk Makes You Sick
Day 5 B5.1c Simulating the Radioactive Decay of C-14
B5.1f Fossil and Migration Pattern in
Early Hominids
Day 6 B5.1c Laetoli Footprints
Chronology of Hominids

 

 

 

25

 

Table 1: Sequence of events for Evolution Unit Continued

 

Day State Objective Addressed Activities

Day 7 B5.1A, B5.1B, BS.le, B5.lg Bead Bug Blitz

Day 8 BS. 1d, BS.3C, B5.3B Clipbirds and Speciation

Day 9 Review for Test

Day B5.1A, B5.1B, B5.lc, B5.ld, Implementation of Post-Unit Survey

10 B5.1e, B5.1f, B5.1 g, BS.2a, Implementation of Multiple Choice Test“
B5.2b, B5.3A, B5.3B, Implementation of Post-Test

B5.3C, B5.3d, B5.3e, B5.3f

 

 

 

 

 

 

 

 

 

*These activities have been used in the past, but the remaining activities were all new
to the evolution unit.
Overview and Summary of Activities

The activities and simulations used in the evolution unit are briefly described
below. All of the activities included in the unit can be found in Appendix II.
Timeline of the History of Life on Earth (Appendix II A): In this activity, students use
15 meters of cash register tape to make a timeline of the history of life on earth,
beginning with the Big Bang and ending with the present day. Pictures are cutout and
pasted on the timeline, representing the major events of life on earth. Students can
visually see how old the earth is and that human existence represents a very short period
of time, compared to the existence of the planet. This exercise effectively addresses the
misconception that the earth is only 6,000-10,000 years old, and students are amazed to
see how old the earth truly is. Students are able to visually see that the Earth is billions of
years Old, and that life has not always existed on the planet.
Giraffe Simulation (Appendix II B): In this simulation, paper leaves are hung from the
ceiling at varying heights. Students become giraffes, and they are told that they must eat

to survive. In the end, only the tallest students remain. We then discuss what this means

26

for future generations of giraffes, what they will most likely look like and why. Students
enjoy the competition aspect of this simulation, and they seem to understand the end
result and can accurately predict what future generations of giraffes will look like and
explain why the offspring would have certain traits. This simulation introduces the idea
of competition and traits that are more advantageous to survival. Although the simulation
is short, it introduces the idea that organisms compete for a limited amount of resources,
and organisms that are more fit survive to reproduce. It is an effective activity for
introducing the role of competition and natural selection.

A 19‘” Century Journey (Appendix II C): This activity has students map out the
journey of Charles Darwin on a world map, using coordinates and excerpts from
Darwin’s journals. They are also required to draw pictures of what Darwin observed on
the map, and draw conclusions at the end of the activity. Overall, students are able to
identify the variations in organisms Darwin observed. They are also able to see that
Darwin traveled around the world, and his observations were global, not just local.
Human Variation Lab (Appendix II D): This activity is meant for students to observe
the variations that exist within the classroom population. The hand spread of all students
is measured, recorded, and graphed as a classroom set of data. Additionally, students
choose two other variations, and collect data from other individuals. Students are then
asked to hypothesize on the sources of variation in the population, and why variations
exist in a population. In the end, students can identify advantages and disadvantages for
the differences seen in individuals. Overall, the comparison of variations of the
individuals in class begins to address the natural variation that exists in all populations of

organisms. Addressing variation using the student population in the classroom allowed

27

students to observe that variations exist in all populations, including humans. This lab is
more effective than using variations in different populations because the students are the
source of variation and actively involved in the lab.

Adaptations of the Human Hand (Appendix II E): The opposable thumb is a human
adaptation that is easily seen. This activity requires students to perform everyday tasks
with the use of their thumbs, and record the amount of time required to complete each
activity. After the tasks are completed, students must tape their thumbs down, causing
them to become non-functioning. Without the use of their thumbs, students then complete
the same tasks, and time how long each takes to complete. Finally, students compare the
time each task took to accomplish and hypothesize about what life would be like without
thumbs. Also, students are asked to identify other human adaptations and explain why
they are useful. This activity helps students understand that adaptations exist in all
populations, and those adaptations serve a purpose.

When Milk makes you Sick (Appendix II F): Lactose tolerance is actually a mutation
in humans that leads to an adaptation. Many populations are lactose intolerant because
they lack the mutation in the lactase gene. In this activity, students draw pedigrees
following lactose intolerance through families and predicting the mode of inheritance.
Students also graph the percentage of lactose intolerant populations in various countries.
Finally, the students graph the percentage of lactose intolerant individuals in the different
ethnic groups in the United States. Based on the data, students predict where lactose
tolerance originated from and hypothesize as to why the mutation is an advantage.
Students are shocked to find that lactose intolerance is more common than lactose

tolerance. This lab addresses the idea that mutations are not always harmful, and they are

28

another source for variations that lead to adaptations. The opposable thumb and lactose
tolerance are both adaptations that are the result of evolution. Once again, because the
adaptations are related to humans, these activities are more interesting to the students as
they can apply them to their lives.

Simulating the Radioactive Decay of Carbon-14 (Appendix II G): Scientists have to
accurately date fossils to determine where they fit in the tree of life. Carbon-l4 is
radioactive and decays at a predictable rate. Licorice represents C-14 in this lab, and
students experience half-lives by cutting the licorice in half and drawing a curve for the
amount of C-14 remaining after each half-life. Students are then given fossils, and they
must predict how old they are based on the amount of C-14 remaining in the fossil, using
the curve they drew. Students soon see that the amount of carbon-14 is limited, and this
form of dating is only useful for dating fossils of a certain age. This lab exposes students
to the process of dating fossils and the idea that radioactive elements are used to
determine the age of a fossil. Since students are able to practice dating fossils using their
graphs, they become actively involved in the lab. Activities that include food always
seem to increase the interest of the students, and this lab is no exception.

Fossil and Migration Patterns in Early Hominids (Appendix II H): Fossils with
human-like characteristics have been found around the world. Students are given
coordinates for the different taxons of human fossils and asked to map where each of the
fossils was found. Students begin with the oldest known fossils and work through to the
most recent fossils, using different colors to map each taxon. Once the map is completed,

students then hypothesize in which area humans originated fi'om and how they spread

29

throughout the world. Students discover the origin of humans in Africa, based on their
own findings, and not a lecture.

Laetoli Footprints (Appendix II I): In this laboratory investigation, students measure
their height, foot length, and leg length, and graph footprint size vs. height for a
classroom set of data. Students also measure the number of strides they take walking and
rrmning a distance of 20 meters. A set of the Laetoli footprints is available for the
students to measure and investigate. The footprints are images of the original fossilized
footprints found in Tanzania in 1976. Using the measurements of stride and footprint
size, students are able to predict the height of the hominid making the footprints, based
on the information they gathered as a class. This activity shows the type of information
that can be obtained from fossils, and actively engages the students in the investigation.
Fossils provide a significant amount of evidence for evolution. The Laetoli footprint lab
and the fossil migration lab offer students the ability to understand what information can
be gained from studying the fossil record. Students are able to hypothesize about the
origin of humans, and use their data to predict what the Laetoli fossils looked like.
Scientists use fossils to gain a similar understanding of life in the past, and these two labs
provide learners with the chance to act as a scientist.

Chronology of Hominids (Appendix II J): Students are given a range of dates during
which various fossils related to humans lived. These dates are then graphed to show the
changes in hominids over time. Additionally, students find that Homo sapiens, or modern
man, has not existed for as long as the students once previously thought. This activity
also demonstrates that man did not walk with the dinosaurs, and that we are a very young

species.

30

Bead Bug Blitz (Appendix 11 K): Bead bugs are a population of beads that inhabit a
fabric habitat. The activity begins with three different colors of beads populating the
habitat. Students act as predators and try to find the bugs on the fabric. At the end of each
feeding, the remaining bugs reproduce, and the populations typically change overtime,
with one or more of the color populations experiencing extinction. After several rounds
of feeding, the bead bugs are forced to move to a new habitat, which is a different piece
of fabric with different patterns. The predators move too, and continue to eat bead bugs
every generation. In response to the new habitat, the bead bug populations typically
change, and a new color may go extinct or become more dominant. Natural selection
plays an active role in this exercise, and students see how adaptations, like camouflage,
are important to the survival and reproduction of a species. Students enjoy the
competition and challenge of this activity, and start to understand how natural selection
affects a population for a given trait. The process of natural selection is officially
introduced in this lab. Participants in the lab engage in a game of survival and extinction.
Several groups had bead bug populations that went extinct, and populations that
increased significantly in number due to natural selection. The students walk away with a
better understanding of the process of natural selection and how populations change over
time.

Clipbirds (Appendix II L): Two populations of clipbirds are separated by a mountain
chain. The students represent the clipbirds, and the classroom is divided into two groups.
Differences in bird beaks and different types of food available on each side of the
mountain range should cause the two populations to diverge from each other. Each

population starts the same, with two individuals with a large binder clip for a beak, two

31

with a medium size binder clip beak, and two with a small binder clip beak. Energy
requirements to survive and reproduce have been pre-determined. Students compete with
each other to determine survivors. At the end of each feeding, the food is counted for
calories. Some clipbirds die, others survive for another round, and some have enough
energy to reproduce. Once the survivors and offspring are ready, the food supply on each
side of the island changes, and the competition begins again. The purpose of this exercise
is to Show that geographical isolation can lead to changes in populations. This simulation
reveals how populations separated by a barrier change in response to different
environmental pressures. This lab was not as effective as other activities because both

populations of clipbirds went extinct before change was seen.

32

Data and Analysis

The following data are from 21 out of 26 students. Three students chose not to
participate in the study, and two students were not in school on the day of the pre-test or
the post-test, so their data have been omitted. For some aspects of data analysis, I will be
following six students. These students were chosen based on their grades in biology and
their success in other classes. Refer to Table 2 for background information on each of the
students. They have fictional names to maintain confidentiality.

Table 2: Student Descriptions

Name Description

David David is a successful student, with a 4.0
grade point average. He participates in
classroom discussions, and retains
information well. He is an active participant
in the high school band.

Darlene Darlene is also a successful student who
earns A’s in most of her classes. She is
involved in many sports, and also
participates in class.

Drew Drew is an average student, earning mostly
B’s and C’s in class, with an occasional A.
For the most part, Drew would rather work
by himself than with others.

Derek Derek is also an average student. He has
had some problems in other classes, and can
be a handful behaviorally. However, he
participates in activities in class.

Dallas Dallas is a student that struggles, not
because he is not capable but because he has
problems maintaining focus. He does not
always turn in assignments, and typically
receives C’s and D’s in classes.

Devon Devon is also a student that struggles in
class. Attendance is a problem for him, and
he often sleeps in class. He prefers social
commitments to academics, and he typically
receives D’s in class and has failed classes
in the past.

 

 

 

 

 

 

 

 

 

 

 

33

Pre-Survey

Prior to beginning the unit, students participated in a fifteen question pre-survey
to gauge their opinions and attitudes on some of the misconceptions associated with
evolution, see Appendix HI A. Students stated their opinions on a scale of one to five,
with one meaning strongly disagree and five representing strongly agree. A three implies
no opinion on the subject. Figure I shows the mode score for each of the questions
because it was a more usefirl representation of the data than the mean. When the mean
was calculated, the average response for each statement resulted in a three, indicating no

opinion.

 

Figure l: Pre-Survey Mode for the Fifteen Opinion Statements
In summary of the pre-survey, many students had no opinion on the variation that
exists in a population, and they disagree that humans have used artificial selection for

thousands of years. Students did strongly disagree that DNA mutations are always

34

harmful, but also disagreed on the statement that organisms are linked by a universal
genetic code. The majority of students agreed that the species of organisms on Earth were
created at the same time and the earth is 6,000-10,000 years old. Furthermore, students
agreed with the statement that the fossil record is incomplete and new species discovered
today have been on earth for thousands of years. The students agreed that humans as a
population are perfectly adapted. The most common opinion on fitness shows that
students disagree with the statement of fitness being the ability of an organism to survive
and reproduce. Students had a neutral opinion on the definition for a theory. For the
statements concerning evolution, students agreed that there is no evidence for evolution,
evolution is not occurring today, and strongly agree the theory states humans came from
monkeys. Finally, students strongly disagree that humans originated from Africa.

The pre-survey also included questions concerning the nature of science. These
questions were graded on a three-point scale, and included questions on what science is,
what science is based on, and why evolution is considered a theory. Figure 2 illustrates

the students understanding of science.

35

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

j

1 2 3
SurveyOuestlon

[IScoreofO IScoreoH IScoreon IScoreors]
Figure 2: Pre—Survey Points per Question for the Nature of Science

 

 

Many students incorrectly defined science as the study of life, the definition for
biology. For instance, Darlene stated that, “Science is the study of living organisms and
their environment.” Other students, like David and Devon stated that science is the study
of everything, another common answer among students. Many students stated that
science is based on theories, facts, and evidence. Finally, most students did not have an
answer for why evolution is considered a theory, as they gave no answer, or “I don’t
know.”

The remaining questions on the pre-survey were based on opinions.
Overwhehningly, students agreed that labs and activities enhance their learning, based on
their previous experiences with hands-on activities. When asked for their opinion on
evolution, students could be grouped into three categories. Five students thought that

evolution happens; fourteen students felt that evolution was not real, and two students

36

had no opinion about the theory. Ten students agreed that evolution should be taught in
schools because they did not know very much about the theory. Six students felt that
evolution should not be taught in school because it does not agree with their religious
beliefs. Finally, five students did not know whether evolution should be taught in schools.
When asked where life on earth originated, sixteen students stated that God created life
on earth. Three students stated that life on earth originated with the Big Bang, and two
students did not have an opinion.
Post-Survey

Following the end of the laboratory activities, the students completed a post-
survey (Appendix HI A). Once again, the mode was calculated for each of the fifteen
opinion questions, where students answered on a scale of one to five, with one meaning
strongly disagree and five representing strongly agree. A three implies no opinion on the

subject. Figure 3 shows a comparison between the pre-survey and post-survey modes.

37

 

123456789101112131415
QuestionNunInr

 

[I Pre—Survey Post-Survey I

 

Figure 3: Pre—Survey and Post-Survey Mode for the Fifteen Opinion Statements
The results in Figure 3 show the most common answers for each of the fifteen
questions. For question one, students strongly agree that variation exists within members
of a population and for question two, that artificial selection has been used by humans for
thousands of years. Overwhelmingly, students strongly disagreed that DNA mutations are
always harmful as represented by question three, and regarding statement four where
organisms are linked by a universal genetic code, the students held a neutral opinion.
Students disagreed that most species on earth were created at the same time, and strongly
disagreed on the statement of the earth being 6,000 to 10,000 years old, statements five
and six respectively. Participants disagreed with statement seven that the fossil record is
incomplete, but they agreed that new species discovered today have been on earth for

thousands of years for statement eight. Furthermore, students disagreed with statement

38

nine that humans are perfectly adapted, and strongly agreed on statement ten regarding
fitness. Most commonly, students strongly disagreed on statements eleven and twelve
that a theory is just a guess, there is no evidence for evolution, and statement thirteen that
evolution is not occurring in organisms today. Students disagree with statement fifteen
that humans originated from Afiica but students reported a neutral opinion concerning
statement fourteen where evolution states that humans came from monkeys.

Post-Survey Questions

 

 

 

///,,

Number of Students

 

 

Survey Question

 

LIScore ofO IScoreof1IScoreof2 IScoreofSI

Figure 4: Post-Survey Points per Question on the Nature of Science

For the open-ended survey questions, students still seemed fixated on defining
science as the study of life or the study of everything. Very few defined science as did
David, “Science is the study of things you can prove.” Dallas defined science as
“something testable.” The majority of students stated that science is based on some type

of evidence, like theories, facts, proof, or experiments. Finally, Darlene said that

39

evolution is considered a theory because, “It is testable and experimental but not yet
proven.” Some students continued to address this question by stating evolution is a theory
because it has not yet been proven. However, other students like David and Derek said
that evolution is a theory because there is “evidence supporting it.”

The opinion questions on the post survey revealed that 100% of the students felt
that labs and activities enhance their learning, with most citing that hands-on activities
help them remember things. When asked about their opinion on evolution, eight students
reported that evolution is “real” and six reported that evolution is possible. Four students
reported that evolution is false, and three did not have an opinion. The majority of
students thought that evolution should be taught in schools. Devon stated that evolution
should be taught because it is “highly logical.” Fourteen students agreed with Devon, and
felt that evolution should be taught in schools, with many citing that they found the topic
interesting and they thought it was a good explanation. Only three students felt that
evolution should not be taught in schools, with one person stating there was no evidence
for the theory, and four students had no opinion on the subject.

Finally, when asked where they thought life on earth originated fiom, six students
stated that life on earth was the result of the Big Bang. Derek said life originated from,
“The big boom because evidence supports it.” Five students reported that God created
life, and five students stated that life on earth started as a small organism, like bacteria.
David said, “I think that we mutated and evolved from microscopic organisms.” An
additional five students said that they did not know how life started or reported no

opinion.

40

Pre-Test

In addition to the survey, a pre-test was also given in order to gather information
about the prior knowledge students had regarding natural variation, natural selection, the
theory of evolution, and speciation. The pre-test was graded on a three-point rubric

(Appendix HI D). Figure 4 shows the average scores for each of the fifteen questions.

 

 

 

 

 

     
      

131

10 11 12 4 15

     

 

o
1 2 3 4 5 e 7 a 9
TeetOuestlon
LIScoreofO IScoreoH IScoreon IScoreofB]

 

 

Figure 5: Pre—Test Points per Question

Many students were able to define variations as differences, but they did not apply
the definition to populations of organisms. Many students also answered question number
two correctly. They could provide at least one variation within a population. According to
Devon, “An adaptation is a mutation to adapt to the environment.” Darlene stated, “An
adaptation is something that helps something survive.” Several students were able to

define an adaptation as something that helps an organism, but did not identify adaptations

41

as something that must be inherited. For question six, students were asked to give an
example of a human adaptation and explain why it is useful, and some participants were
able to list a trait, like height, but did not explain its usefulness. The final question that
students performed better than expected required them to identify what is necessary for
an idea to become a theory. Answers ranged from facts to evidence, but most focused on
proof, as a pre-requisite for an idea to become a theory. Students were not able to
describe what the theory of evolution states, but some were able to state that DNA and
fossils provide evidence for evolution.
Post-Test

A post-test was also administered (Appendix III D). Figures 6 showsithe

distribution of students receiving scores from zero to three.

18

Number of Students

 

123456789101112131415
TeetQueetion

 

[lscoreoro IScoreof1IScoreof2 IScoreof3]

Figure 6: Post-Test Points per Question

42

Very few students were able to answer questions three, four, nine, and fifteen.
Question three asked students to provide the two main sources of genetic variation within
a population. Many students could identify mutations as a source of genetic variation but
could not cite sexual reproduction as the other source. Darlene answered question four in
the following manner, “Mutations in gametes can be passed on because they are in the
genes of the gamete and the genes are passed down.” Participants struggled with question
four, and many left the question blank. Overall, question nine and fifteen resulted in a
score of zero most often. Question nine asked students to describe the role of the
environment in natural selection. David answered this question as follows, “If an
animal’s habitat is destroyed by a natural disaster, then they would move and adapt to
their new surroundings.” Dallas stated, “Some animals are more fit for their environment,
like faster, camouflage, stronger, or keener.” Finally, question fifteen asked students to
explain how geographic isolation could result in speciation. Derek answered, “The two
species would eventually change and not be able to reproduce with each other.” Darlene
remarked that geographical isolation “makes organisms adapt to the environment. One
species could be split because of a mountain and both sides would have to adapt to the
environment.”

Figure 7 represents a comparison of the mean scores for each question on the pre-

test and post-test. Questions were scored on a scale of zero to three.

43

 

 

 

I Pre-Test I Post-Test

Figure 7: Mean Scores for Pre-Test and Post-Test

The scores on the post-test were higher than the scores for the pre-test for all
fifteen questions, as seen in Figure 7. This indicates that the students increased their
understanding of evolution following the unit.

Paired T-Tests

The pre—test and post-test data was compared using paired t-tests as a statistical
analysis for each individual student. The null hypothesis states that hands-on activities do
not aid students in learning evolution, and can be rejected if the p-value is less than 0.05.
Table 3 shows the p-values for each student. Students were randomly assigned letters to

maintain confidentiality.

Table 3: P-values for Paired T-Tests of Pre—Test and Post-Test

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Student ID P-Value Student ID P-Value

A 5.1 E-08 L 2.8E-02
B 2.7E-04 M 1 .2E-08
C 3.0E-O3 N 8.0E-06
D 5.5E-02 O 6.6E-04
E 4.6E-08 P 2.8E-04
F 2.1 E-06 Q 6.4E-04
G 2.3E-05 R 1 .3E-04
H 4.0E-03 S 8.9E-05
I 7.0E-06 T 7.6E-05
J Undefined U 1 .5E-04

Labs and Activities

There was not a post-lab test given, but analysis of the laboratory questions is
included as a subjective gauge of student learning. The timeline, beginning with the Big
Bang and ending at the present, did not have a written aspect to it. Students responded to
the activity with statements like, “I didn’t know that the earth was that old,” and “A lot
happened in such a short amount of time!” Also, students stated that, “There are long
periods of time, where nothing happened,” and “We have not been around for a very long
time.”

The giraffe simulation also did not have a written response involved in the
activity, but students still had comments to share. Many stated, “This is discrimination
against short people!” Despite the elimination of several students based on height,
students could respond to questions about the future generations. “The next generation of
giraffes should be taller because the genes for shortness have been eliminated.” “Future
generations should gradually get taller.” In response to questions concerning what caused
the change, students responded with, “Competition and nature caused the changes to
occur.” Questions concerning why some giraffes survived, while others did not resulted

in responses like, “They were taller and better adapted to survive.”

45

According to Drew, Darwin observed, “cliffs, beaches, islands, plains, and
volcanoes” during the activity on Darwin’s Journey. Darlene identified observations like,
“different climates, animals, plants, and landscapes.” David provided more complete
answers concerning Darwin’s journey. “They found a colony of people in the middle of
nowhere that were quite civilized.” He also declared, “They found a lot of remains of
large animals in Buenos Aires,” and “In Cape Verde, they found some cows and goats,
even though they don’t have much food.” All students were able to identify some of
Darwin’s observations that lead to the theory of evolution.

When questioned on the definition of variations, Drew stated, “The differences
between two or more organisms of a species,” following the human variation activity.
Darlene’s group defined variations as the “difference within a species.” Most groups
were able to identify that variations are differences between organisms. When asked to
explain the significance of having variations within the human population, Dallas
remarked, “So each person could be who they really are, and not be worried because
there are others like them.” Drew responded to the same question, with, “The uniqueness
allows the species, in one way or another, to adapt to any climate.” Answers to this
question varied. Few students were able to identify the source of variations in a
population, but Dallas answered with genetics. Most of the other groups left the question
blank. All groups were able to list variations that exist between humans, such as blood
types, hair color, foot size, weight, height, and many others.

Adaptations of the human hand asked students to explain how the human hand is
adapted for performing everyday actions. Darlene responded, “Your thumbs help you

grip things,” and Dallas stated, “The thumb is more free to move in all directions.” Drew

46

said, “My hands are adapted to do the actions I tested and others by having opposable
thumbs and fingers.” Students were also asked to identify adaptations that exist in other
species. David provided the following answer, “A dogs nose is an adaptation because
they can smell better than hrunans.” Devon added, “The gills of fish are adapted for
breathing underwater.”

The study of adaptations continued with the lactose tolerance activity. Students
were asked to hypothesize as to the origin of lactose tolerance. The most common
hypothesis stated that lactose tolerance originated in European countries because they
could raise cows in that climate. David’s hypothesis was, “European countries are where
it originated because they have more cows and can store milk longer.” Drew further
explained, “They evolved the mutation to keep the lactose gene active because their main
source of protein and other nutrients was milk.” Students were able to identify where the
mutation most likely occurred and why it was maintained in the populations.

For the simulation of the radioactive decay of carbon, students could date the
fossils, and explain why carbon-14 is not useful for fossils more than 50,000 years old.
According to David, carbon-14 is no longer useful after 50,000 years “because there is
not enough carbon-l4 left to tell how old the fossil is.” Derek suggests, “the carbon-l4 is
gone, and you have to test for something else.” Students were also able to predict that a
fossil with 5.5 percent of the original carbon-14 remaining would be between 23,000 and
28,000 years old.

Following the activity involving the migration patterns of hominids, and after
perfomring the Laetoli footprint lab, students were asked to identify the type of

information that could be inferred based on the footprints found in a backyard. Darlene

47

stated, “You could determine a person’s foot size, height, and weight, and if they were
rrmning or walking, but you couldn’t determine any other physical features.” Similarly,
Devon wrote, “They could tell if the person was running and if they were tall or not. You
could not tell how old the person was or what they looked like.” The class was able to
predict how tall a person what based on his foot length by using the classroom data.

“The Homo neanderthalensis and Australopithecines are fossils found pretty
much around the same place, but Homo sapiens and Homo erectus are here and all over,”
according to Devon, in response to a question asking to describe the overall pattern of
hominid migration. David answered with the following response: “They branched out in
different directions as they moved to different environments.” Dallas reported that Afiica
is the “birthplace” of hominids, “Because Afiica has the most found hominids (human
fossils) than any other continent in the world.” Drew. answered the same question by
stating, “Afiica is considered the birthplace because the oldest hominids were found in
Afiica.” The learners were able to hypothesize why Afiica is considered the birthplace of
hominids and the overall pattern of hominid migration. Other than placing the hominid
fossils in chronological order, the chronology of hominids did not ask students specific
questions. However, students were shocked to see that Homo sapiens “have not been
around for very long.”

In the Bead Bug activity, students were asked if any specific color of head bug
went extinct, and to explain why extinction occurred. Most groups had a population
experience extinction. David reported, “Blue and red went extinct because they didn’t
have very good camouflage.” Drew stated, “Orange went extinct because it stood out too

much.” After the bead bugs moved to a new habitat, students were asked to relate this

48

move to an event in real life, and most could state that the move represented a natural
disaster. The learners also hypothesized what would happen if all of the bead bugs were
green to begin with. Students stated that there would not be any changes in the population
over time. Drew said that the populations would not change because of a lack of
variation, as did Derek and Darlene. Despite a lack of variation, students predicted that
the green bead bugs would be able to adapt in the future if the organisms had to re-locate
to a new environment. In response to the question, Dallas stated, “The bead bugs can
adapt, but there would have to be a mutation.” However, Darlene disagreed by saying,
“The green bead bugs would not be able to adapt because there is no variation.”

Clipbirds, the final hands—on activity asked students to identify the role of the
mountain range in the lab. Derek stated, “It separates the two sets of birds,” and Drew
said, “It divides the two populations in half.” When asked to predict what beak size
would be the most adapted for survival, students thought the small beak would provide an
advantage. Darlene stated that her predictions “were so far off, I thought the small beak
would win, but they didn’t.” The participants were also asked to explain whether or not
Speciation was occurring in the two populations. According to Devon, “Speciation is not
occurring because one population went extinct.” Dallas felt that, “Speciation is occurring
because more large beaked clipbirds survived initially.” The question concerning
Speciation provided a variety of responses because the activity did not end as expected.
Even though students were unsure if Speciation was occurring, they did identify the type
of isolation as geographical isolation because of the mountain range dividing the two

populations.

49

Multiple Choice Test

Students in past semesters took a forty point multiple choice test at the end of the
evolution unit. Since student tests are typically multiple choice, and they are familiar with
this assessment format, I decided to also give the students the same version of the
evolution multiple choice test that was used in the past (Appendix HI E). Figure 8 shows

the results of the number of students that answered each question correctly.

25'

 

B

.L
0

Number of Correct Answers
a

 

13 5 7 9111315171921232527293133353739
OueetlonNunber

Figure 8: Number of Correct Answers for Multiple Choice Questions

The questions that were answered incorrectly most often dealt with the
types of selection, as in number 24, 25, and 26. Additionally, question 31 asked students
about genetic drift, and question 33 and 35 asked students about the different isolation
mechanisms involved in speciation. The rest of the test questions had more students

answering correctly, with questions 6, 16, 18, and 19 answered correctly by all students.

50

Conclusions

Overall, I feel that the evolution unit went quite well. The class involved in the
research responded well to the activities, and appeared to enjoy participating in the
hands-on labs, while learning something at the same time as indicated by the scores on
the post-test and multiple choice tests, Figures 6 and 8. Although I spent two weeks on
the evolution unit, I needed more time to include all of the labs and activities that were
developed at Michigan State University in the summer of 2007. I actually had thirteen
days set aside to complete the unit, but three of those days were lost due to poor weather,
and school was cancelled. All labs that were not used in the research can be found in
Appendix II.

Due to the cancelled days, I ran out of time to teach everything that I planned. The
Lab Assessment was not given to the students because of a shortage of time.
Additionally, I did not give a final exam in this particular biology class in order to
complete the evolution unit. Despite the interference of the weather, I think that the labs
and activities included in the curriculum were advantageous to the learners as evidenced
by their success on the post-test and the change in attitude seen in the post-survey, Figure
3. The majority of the labs were repeated in the biology spring semester class. These
students were not included in the research data because of where the evolution unit falls
in the curriculum. Since it is the last unit I teach, I did not feel that there would be
sufficient time to collect and analyze all of the data if these students were included also.
Survey Results

The pre-unit survey helped to provide insight for the misconceptions of the

students and gauge their opinions and attitudes concerning evolution and the nature of

51

science. Many students changed their perception of the theory of evolution because of the
hands-on activities and their experiences with the concepts of evolution in the classroom,
as seen in Figure 3, where the pre-survey and post-survey modes are compared. In the
past, students did not change their perception because the activities included in the
evolution unit were not hands-on and were dependent on the information in the book. The
personal encounters with evolutionary concepts helped to challenge misconceptions, prior
knowledge, and attitudes. At the end of the unit, fewer students felt that humans were not
still evolving, and less students thought that evolution stated that man evolved fi'om
monkeys.

For instance, students went from a neutral opinion to strongly agreeing that
variation exists within a population. Interestingly, the mode for the statement that the
earth is 6,000-10,000 years old went fi'om the students agreeing in the pre-unit survey, to
disagreement in the post-unit survey. I believe this is the result of the timeline activity,
where the students could visualize how old the earth really is. Another interesting shift in
opinion occurred for the statement on the fossil record. Prior to the unit, students agreed
that the fossil record was incomplete, but after completion, students disagreed with the
statement. There were several activities that required students to work with fossils, and
these too helped to shift the attitudes of the students.

An additional change in opinion resulted for the statement that there is no
evidence for evolution. Initially, students agreed that there is a lack of evidence, but after
the unit, the students strongly disagreed. The same shift in opinion occurred for the
statement that evolution is not occurring in organisms today. These are significant

changes in opinion for a small community with strong religious ties. In the past, many

52

students started and ended the evolution unit with the same misconceptions, based on
conversations with the students following the unit test, but with the inclusion of the labs
and activities, the students involved in this study were challenged to question their prior
knowledge.

Even though most students were unable to provide a well-developed definition for
science, they were able to explain that science is based on evidence, experiments, proof,
and facts. They were also able to explain why evolution is considered a theory. In the
future, I would like to address the issue of defining science with a classroom activity
where students provide words that they think mean science. These words would then be
placed on a bulletin board and referenced throughout the year.

The survey revealed a change in student opinions concerning evolution. When
asked for their opinions of evolution prior to the unit, fourteen students said that the
theory was not true at all. After the unit, the number of students stating that evolution was
not possible was reduced to four. More students also felt that evolution should be taught
in schools after the completion of the unit. Finally, for the question concerning the origin
of life on earth, sixteen students believed God created life on the pre-unit survey. On the
post-unit survey, fifteen students provided a different explanation. The shift in attitudes
and opinions is the direct result of teaching evolution through hands-on activities and not
depending on lectures and book assignments alone to teach the concepts of evolution.
The active involvement in the learning process challenges the students to change their

opinions and prior knowledge, as evidenced by the transformation of opinions.

53

Discussion of Labs and Activities

The labs and activities that were included in the evolution unit were fun for the
students, and engaged them in the learning process. Students overwhelmingly agreed that
hands-on activities increased their learning and retention of information. As an extra
credit question on the evolution test, I asked students to pick their favorite lab from the
entire semester. One student answered that the Bead Bug Blitz was his favorite lab
because it was challenging and fun. Hands-on activities provide a more valuable learning
experience for the students, and I think this is evidenced by the multiple choice test. The
overall average on the evolution multiple choice test increased for both biology sections
this year. For the two semesters prior to the research, the student average on the test was
70%, but the average increased to 85% for the two classes where labs were included.

Students appeared to have a better understanding of the material, as a result of the
new activities. Since there was such an improvement on the evolution test for the fall
semester, I decided to continue to use the labs for the spring semester, and the same
success resulted. In addition to showing improvement, the multiple choice test results
also pointed out some areas that need more work. For instance, isolation mechanisms in
the process of speciation need to be emphasized more, and I think this can be addressed
with the Clipbird lab, once it is re-worked. To correct the Clipbird lab, the energy levels
required to survive or reproduce must be decreased in order for the students to see that
geographical isolation can lead to speciation. Otherwise, all of the birds went extinct
when this lab was used, and the students did not experience speciation as a result of
geographical isolation. Also, the different selection mechanisms need to be addressed

more thoroughly, and I will have to search for or develop a lab to confi'ont this issue. The

54

activities not included in the unit might help confront these issues as well, and I would
like to incorporate them in the future.
Pre-Test and Post-Test

In order to reject the null hypothesis, stating that hands-on activities do not help
students learn evolutionary concepts, the p-value for the paired t-tests must be less than
0.05. The null hypothesis can be rejected for all but two of the students that participated
in the study. Student D had a p-value of 0.06 because she left the majority of the
questions on the pre-test and post-test blank. Based on previous units, Student D did not
score well on tests, and had difficulty with short answer questions. Since Student D left
the majority of the questions blank, it was difficult to gauge learning because there was
nothing to grade. For Student J, no p-value could be assigned because no points were
scored on either the pre-test or the post-test. Student J also had problems with short
answer questions on previous tests, and often chose not to answer them at all. On the
post-test, Student J’s answers made no sense and did not pertain to the questions.
Although these two students did not perform well on the post-test, the remaining nineteen
students did. These students had p-values that were less than 0.05, so the null hypothesis
can be confidently rejected.

The questions that seemed to provide the most difficulty for the students were
those dealing with natural selection. I think that because there was only one lab that
centered on natural selection, the students struggled with the concept. The Jumping Frog
lab (Appendix II 0) that was not used may help to address this issue in the future. Also,
students seemed to struggle with the question dealing with geographic isolation, and this

was supported by the multiple choice results as well. Once again, changing the Clipbird

55

activity so that the birds survive should help to alter student responses for geographic
isolation.

Based on the p-values and the multiple choice test, the students did gain a better
understanding of evolution due to the labs and activities that were incorporated into the
biology curriculum. Since the notes and information remained the same, and the only
change made to the evolution unit was the inclusion of the activities, I can confidently
report that the activities significantly improved student learning. The change in attitudes
observed on the survey also provides support for student learning through activities.
Overall, the research and study can be considered a success because of the significant
improvement in test scores and attitudes.

Summary

In conclusion, I feel that the evolution unit was a success, and the labs and
activities utilized to teach evolutionary concepts will be used again. As mentioned
previously, I would like to include more of the labs that snow days did not permit me to
use this past school year. By the end of the unit, the students were not bored with the
topic, and they wanted to do more hands-on activities, there just was not significant time
to accommodate their requests.

For the future, I would like to address the issue of defining science more
accurately in the classroom and work to improve scientific literacy in the student
population. Challenging the students to confront their misconceptions and change their
existing knowledge to incorporate new ideas will help to increase their scientific

understanding of the world around them. I plan to continue to use the evolution activities

56

developed during the course of my research and search for new activities that will

supplement the weaker parts of the evolution curriculum.

57

APPENDICES

58

APPENDIX I

Michigan High School Content Expectations for Evolution

59

Michigan High School Content Expectations for Evolution

BS. lA- Summarize the major concepts of natural selection (differential survival and
reproduction of chance inherited variants, depending on environmental conditions).

B5. lB-Describe how natural selection provides a mechanism for evolution.
B5. lc - Summarize the relationships between present-day organisms and those that
inhabited the Earth in the past (e. g., use fossil record, embryonic stages, homologous

structures, chemical basis).

B5.ld - Explain how a new species or variety originates through the evolutionary process
of natural selection.

B5.le - Explain how natural selection leads to organisms that are well suited for the
environment (differential survival and reproduction of chance inherited variants,
depending upon environmental conditions).

BS. 1 f - Explain, using examples, how the fossil record, comparative anatomy, and other
evidence supports the theory of evolution.

B5.l g - Illustrate how genetic variation is preserved or eliminated fi'om a population
through natural selection (evolution) resulting in biodiversity.

BS.2a— Describe species as reproductively distinct groups of organisms that can be
classified based on morphological, behavioral, and molecular structures.

B5.2b-Explain that the degree of kinship between organisms or species can be estimated
from similarity of their DNA and protein sequences.

B5.2c- Trace the relationship between environmental changes and changes in the gene
pool, such as genetic drift and isolation of subpopulations.

B5.3A — Explain how natural selection acts on individuals, but it is populations that
evolve. Relate genetic mutations and genetic variety produced by sexual reproduction to
diversity within a given population.

BS.3B — Describe the role of geographic isolation in speciation.

BS.3C — Give examples of ways in which genetic variation and environmental factors are
causes of evolution and the diversity of organisms.

B5.3d — Explain how evolution through natural selection can result in changes in
biodiversity.

60

BS.3e — Explain how changes at the gene level are the foundation for changes in
populations and eventually the formation of a new species.

B5.3f — Demonstrate and explain how biotechnology can improve a population and
species.

61

APPENDIX II

Activities and Labs

62

Appendix II A: Timeline of the History of Life on Earth
Adapted from: The History of Everything
http://www.fresno.k12.ca.us/schools/sO90/_atkinsgatebio/timelineproj ect/tmlinefstpage

Procedure:

1. Measure as accurately as possible 15.5 meters of three-inch wide cash register tape.

2. Measure 25 centimeters fiom one end draw a line straight across the tape and label it
"Present" or "Now".

3. Accurately measure and label the years ago every 10 centimeters (100 million years),
make and label time markers (lines straight across the tape) until you reach the 5 meter
mark (5 billion years ago), then change the time markers to every 50 centimeters. Do this
until you reach 15 billion years ago. You may wish to go back and use a darker line to
show the billion year marks.

4. Cut out and paste the pictures at the corresponding time on the timeline.

5. Pictures can be found at:
http://www.fresno.kl2.ca.us/schools/sO90/__atkinsgatebio/timelineproject/tmlinefstpage

63

Appendix II B: Giraffe Simulation

For this simulation, the teacher needs to hang paper leaves fiom the ceiling at
various heights. The students are then told that they will be acting as giraffes. In order to
survive, the giraffes need to eat. Giraffes are not allowed to jump or climb on furniture to
grab a leaf. Divide the room in half, and have one half of the students eat, followed by the
other half of the students. If a giraffe cannot eat, then they do not survive and can no
longer participate in the simulation. Continue to do this until there are only a few students
left. Discuss what future generations of Offspring will look like based on the students who
are left standing.

64

Appendix II C: A 19"I Century Journey
Adapted from: PBS Evolution, Who was Charles Darwin
http://www.pbs.org/wgbh/evolution/educators/lessons/lesson2/act1 .htrnl

Introduction: Traveling in the 1830’s was expensive and dangerous. Few people went
very far fi‘om their homes. However, it was also a time of great discovery and
colonization. At this time, a young man had just recently graduated from Cambridge
University with a Bachelor’s of Art degree. He was planning to follow in his father’s
footsteps and become a physician, but he could not stand the sight of blood. His interests
extended beyond the arts to nature, including botany and geology. Eventually, he became
a pastor in a small church so that he could also study natural history.

In 1831, this young man was invited to voyage on a ship called the Beagle to
explore the shores of Chile, Peru, and island in the Pacific. He took the job as an unpaid
naturalist and recorded his observations on his expedition.

Purpose: To map the journey of a young naturalist and identify key observations from
the voyage and hypothesize what they mean.

Procedure:

1. Using the excerpts from The Voyage of the Beagl_e and a world map, plot the
voyage. You should include the date at each location and number the locations in
chronological order.

2. Connect the locations with a line, starting and ending in England.

3. When you are finished with your map, you should illustrate it. Use small pictures
to illustrate the observations made on the voyage. If you do not have enough room
on the map, you may draw on a separate piece of paper and number them to
correspond to the map.

4. List at least 5 significant observations made on the journey in one column and
write how the observations contribute to the development of natural selection.

65

Excerpts fi'om Voyage of the Beagle
Adapted from www.1iterature.org

Devonport, England: 50° N, 4° W

December 27, 1831

After having been twice driven back by heavy southwestern gales, Her Majesty’s ship
Beagle, a ten-gun bri , under the command of Captain Fitz Roy, R.N., sailed from
Devonport on the 27t of December, 1831. The object of the expedition was to
complete the survey of Patagonia and Tierra del F uego, commenced under Captain
King in 1826 to 1830—to survey the shores of Chile, Peru, and of some islands in the
pacific — and to carry a chain of chronometrical measurements round the World.

Cape Verde, Porto Praya: 14° N, 23° W

January 16, 1832

The neighbourhood of Porto Praya, viewed from the sea, wears a desolate aspect. The
volcanic fires of a past age, and the scorching heat of a tropical sun, have in most
places rendered the soil unfit for vegetation. The island would generally be
considered as very uninteresting. A single green leaf can scarcely be discovered over
wide tracts of the lava plains; yet flocks of goats, together with a few cows, contrive
to exist. It rains very seldom, but during a short portion of the year heavy torrents fall,
and immediately afterwards a light vegetation springs out of every crevice. . ..

Rio de Janeiro, Brazil: 23° S, 43° W

July 5, 1832

In the morning we got under way, and stood out of the splendid harbour of Rio de

J aneiro. In our passage to the Plata, we saw nothing particular, excepting on one day a
great shoal of porpoises, many hundreds in number. As soon as we entered the
estuary of the Plata, the weather was very unsettled. One dark night we were
surrounded by numerous seals and penguins, which made such strange noises, that the
officer on watch reported he could hear the cattle bellowing on shore. On a second
night we witnessed a splendid scene of natural fireworks; the mast-head and yard-
arm-ends shone with St. Elrno’s light. . ..

Tierra del Fuego, Argentina: 55° S, 73° W

December 17, 1832

Having now finished with Patagonia and the Falkland Islands, 1 will describe our first
arrival in Tierra del Fuego. A little after noon we doubled Cape St. Diego, and
entered the famous strait of Le Maire. We kept close to the Fuegian shore, but the
outline of the rugged, inhospitable Statenland was visible amidst the clouds. In the
afternoon we anchored in the Bay of Good Success. While entering we were saluted
in a manner becoming the inhabitants of this savage land. The savages followed the
ship, and just before dark we saw their fire, and again heard their wild cry. The
harbour consists of a fine piece of water half surrounded by low rounded mountains
of clay-slate, which are covered to the water’s edge by one dense gloomy forest. A

66

single glance at the landscape was sufficient to Show me how widely different it was
from anything I had ever beheld. . ..

Maldonado, Uruguay: 34° S, 54° W

July 24, 1833

The Beagle sailed fiom Maldonado, and on August the 3rd she arrived Off the mouth
of the Rio Negro. This is the principal river on the whole line of caost between the
Strait of Magellan and the Plata. It enters the sea about three hundred miles south of
the estuary of the Plata. About fifty years ago, under the old Spanish government, a
small colony was established here; and it is still the most southern position (lat. 41°)
on this eastern coast of America, inhabited by civilized man.

Buenos Aires, Argentina: 34° S, 59° W

August 24, 1833

The Beagle arrived here on the 24th of August, and a week afterwards sailed for the
Plata. With Captain Fitz Roy’s consent I was left behind, to travel by land to Buenos
Ayres. I will here add some observations, which were made during this visit and on a
previous occasion, when the Beagle was employed in surveying the harbour.

The plain, at the distance of a few miles from the coast, belongs to the great Pampean
formation, which consists in part of a reddish clay, and in part of a highly calcareous
marly rock. Nearer the coast there are some plains formed from the wreck of the
upper plain, and from mud, gravel, and sand thrown up by the sea during the slow
elevation of the land, of which elevation we have evidence in upraised beds of recent
shells, and in rounded pebbles of pumice scattered over the country. At Punta Alta we
have a section of one of these later-formed little plains, which is highly interesting
fiom the number and extraordinary character of the remains of gigantic land-animals
embedded in it. I will here give only a brief outline of their nature.

First, parts of three heads and other bones of the Megatherium, the huge dimensions
of which are expressed by its name. Secondly, the Megalonyx, a great allied animal.
Thirdly, the Scelidotherium, also an allied animal, of which I obtained a nearly
perfect skeleton. It must have been as large as a rhinoceros: in the structure of its head
it comes, according to Mr. Owen, nearest to the Cape Anteater, but in some other
respects it approaches to the armadillos. F ourthly, the Mylodon Darwinii, a closely
related genus of little inferior size. Fifthly, another gigantic edental quadruped.
Sixthly, a large animal, with an osseous coat in compartments, very like that on an
armadillo. Seventhly, an extinct kind of horse, to which I shall have again to refer.
Eighthly, a tooth of a Pachydermatous animal, probably the same with the
Macrauchenia, a huge beast with a long neck like a camel, which I shall also refer
again. Lastly, the Toxodon, perhaps one of the strangest animals ever discovered: in
size it equaled an elephant or megatherium, but the structure of its teeth, as Mr. Owen
states, proves indisputably that it was intimately related to the Gnawers, the order
which, at the present day, includes most of the smallest quadrupeds.

The remains of these nine great quadrupeds, and many detached bones, were found
embedded on the beach, within the space of about 200 yards square. It is a remarkable

67

circumstance that so many different species should be found together; and it proves
how numerous in kind the ancient inhabitant of this country must have been. . ..

The remains at Punta Alta were embedded in stratified gravel and reddish mud, just
such as the sea might now wash up on a shallow bank. They were associated with
twenty-three species of shells, of which thirteen are recent and four others very
closely related to recent forms. . ..

Port St. Julian, Argentina: 49° S, 67° W

January 9, 1834

Everything in this southern continent has been effected on a grand scale: the land,
from the Rio Plata to Tierra del Fuego, a distance of 1200 miles has been raised in
mass (and in Patagonia to a height of between 300 and 400 feet), within the period of
the now existing sea-shells. I have said that within the period of existing sea-shells,
Patagonia has been upraised 300 to 400 feet: I may add that within the period when
icebergs transported boulders over the upper plain of Santa Cruz, the elevation has
been at least 1500 feet. Nor has Patagonia been affected only by upward movements:
the extinct tertiary shells from Port St. Julian and Santa Cruz cannot have lived,
according to Professor E. Forbes, in a greater depth of water than fi‘om 40 to 250 feet;
but they are now covered with sea-deposited strata fiom 800 to 1000 feet in thickness:
hence the bed of the sea, on which these shells once lived, must have sunk
downwards several hundred feet, to allow the accumulation of the superincumbent
strata. What a history of geological changes does the simply-constructed coast of
Patagonia reveal!

Bay of S. Carlos, Chile: 42° S, 73° W

January 15, 1835

On January the 15th we sailed from Low’s Harbour, and three days afterwards
anchored a second time in the bay of S. Carlos in Chiloe. On the night of the 19th the
volcano of Osomo was in action. At midnight the sentry observed something like a
large star, which gradually increased in size till about three o’clock, when it presented
a very magnificent spectacle. . ..

Valdivia, Chile: 39° S, 73° W

February 20, 1835

This day has been memorable in the annals of Valdivia, for the most severe
earthquake experienced by the oldest inhabitant. I happened to be on shore, and was
lying down in the wood to rest myself. It came on suddenly, and lasted two minutes,
but the time appeared much longer. The rocking of the ground was very sensible. The
undulation appeared to my companion and myself to come from due east, whilst
others thought they proceeded from southwest: this shows how difficult it sometimes
is to perceive the directions of the vibrations. There was no difficulty in standing
upright, but the motion made me almost giddy: it was something like the movement
of a vessel in a little cross-ripple, or still more like that felt by a person skating over
thin ice, which bends under the weight of his body. A bad earthquake at once destroys
our oldest associations: the earth, the very emblem of solidity, has moved beneath our
feet like a thin crust over a fluid. . ..In the course of the evening there were many

68

weaker shocks, which seemed to produce in the harbour the most complicated
currents, and some of great strength.

Concepcion, Chile: 37° S, 73° W

March 4, 1835

We entered the harbour of Concepcion. While the ship was beating up to the
anchorage, I landed on the island of Quiriquina. The mayor-domo of the estate
quickly rode down to tell me the terrible news of the great earthquake of the 20th: --
“That not a house in Concepcion or Talcahuano (the port) was standing; that seventy
villages were destroyed; and that a great wave had almost washed away the ruins of
Talcahuano.” During my walk round the island, I observed that numerous fiagments
of rock, which, from the marine productions adhering to them, must recently have
been lying in deep water, had been cast up high on the beach; one of these was six
feet long, three broad, and two thick.

Galapagos Islands, Ecuador: 0° S, 90° W

September 15, 1835

This archipelago consists of ten principal islands, of which five exceed the others in
size. They are situated under the Equator, and between the five and six hundred miles
westward of the coast of America. They are all formed of volcanic rocks; a few
fragments of granite curiously glazed and altered by the heat, can hardly be
considered as an exception...

Considering that these islands are placed directly under the equator, the climate is far
from being excessively hot; this seems chiefly caused by the singularly low
temperature of the surrounding water, brought here by the great southern polar
current. Excepting during one short season, very little rain falls, and even then it is
irregular; but the clouds generally hang low. Hence, whilst the lower parts of the
islands are very sterile, the upper parts at a height of a thousand feet and upwards,
possess a damp climate and a tolerably luxuriant vegetation. . ..

September 29th — We doubled the southwest extremity of Albemarle Island...

The rocks on the coast abounded with great black lizards, between three and four feet
long; and on the hills, an ugly yellowish-brown species was equally common. The
whole of this northern part of Albemarle Island is miserably sterile. . ..

The natural history of these islands is eminently curious, and well deserves attention.
Most of the organic productions are aboriginal creations, found nowhere else; there is
even a difference between the inhabitants of the different islands;; yet all show a
marked relationship with those of America, though separated from that continent by
an open space of ocean, between 500 and 600 miles in width. The archipelago is a
little world within itself, or rather a satellite attached to America. . ..

. . ..The remaining land-birds form a most singular group of finches, related to each
other in the structure of their beaks, short tails, form of body and plumage: there are

69

thirteen species, which Mr. Gould has divided into four sub-groups. All these species
are peculiar to this archipelago; and so is the whole group, with the exception of one
species of the sub-group Cactomis, lately brought from Bow Island, in the Low
Archipelago. Of Cactomis, the two species may be often seen climbing about the
flowers of the great cactus-trees; but all the other species of this group of finches,
mingled together in flocks, feed on the dry and sterile ground of the lower districts.
The males of all, or certainly of the greater number, are jet black; and the females
(with perhaps one or two exceptions) are brown. The most curious fact is the perfect
gradation in the size of the beaks in the different species of Geospiza, from one as
large as that of a hawfinch to that of a chaffinch, and (if Mr. Gould is right in
including his sub-group, Certhidea, in the main group) even to that of a warbler.
Seeing this graduation and diversity of structure in one small, intimately related group
of birds, one might really fancy that from an original paucity of birds in this
archipelago, one species had been taken and modified for different ends.

I will first describe the habits of the large tortoises (Testudo nigra, formerly called
Indica), which has been so frequently alluded to. These animals are found, I believe,
on all the islands of the archipelago; certainly on the greater number. They frequent in
preference the high damp parts, but they likewise live in the lower and arid districts. I
have already shown, from the numbers which been caught in a single day, how very
numerous they must be. Some grow to an immense size: Mr. Lawson, an Englishman,
and vice- governor of the colony, told us that he had seen several so large, that it
required six or eight men to lift them from the ground; and that some had afforded as
much as two hundred pounds of meat. The old males are the largest, the females
rarely growing to so great a size; the male can readily be distinguished fiom the
female by the greater length of its tail. The tortoises which live on those islands where
there is no water, or in the lower and arid parts of the others, feed chiefly on the
succulent cactus. Those which frequent the higher and damp regions, eat the leaves of
various trees, a kind of berry (called guayavita) which is acid and austere, and
likewise a pale green filamentous lichen, that hangs from the boughs of trees. . ..

I have not as yet noticed by far the most remarkable feature in the natural history of
this archipelago; it is, that the different islands to a considerable extent are inhabited
by a different set of beings. . .. I never dreamed that islands, about 50 or 60 miles
apart, and most of them in sight of each other, formed of precisely the same rocks,
placed under a quite similar climate, rising to a nearly equal height, would have been
differently tenanted; but we shall soon see that this is the case. ..

Tahiti Island, French Polynesia: 17° S, 149° W
November 15, 1835

At daylight, Tahiti, an island which must for ever remain classical to the voyager in
the South Sea, was in view. At a distance the appearance was not attractive. The
luxuriant vegetation of the lower part could not yet be seen, and as the clouds rolled
past, the wildest and most precipitous peaks showed themselves towards the centre of
the island. . ..

7O

Sydney, Australia: 33° S, 151° E

January 12, 1836

Early in the morning a light air carried us towards the entrance of Port Jackson.
Instead of beholding a verdant country, interspersed with fine houses, a straight line
of yellowish cliff brought to our minds the coast of Patagonia. A solitary lighthouse,
build of white stone, alone told us that we were near a great and populous city.
Having entered the harbour, it appears fine and spacious, with cliff-formed shores of
horizontally stratified sandstone. The nearly level country is covered with thin
scrubby trees, bespeaking the curse of sterility. Proceeding firrther inland, the country
improves: beautiful villas and nice cottages are here and there scattered along the
beach.

Cocos Islands: 12° S, 96° E

April 1, 1836

We arrived in view of the Keeling or Cocos Islands, situated in the Indian Ocean, and
about six hundred miles distant from the coast of Sumatra. This is one of the lagoon-
islands (or atolls) of coral formation, similar to those in the Low Archipelago which
we passed near. .

Port Louis, Mauritius: 20° S, 57° E

May 9, 1836

We sailed from Port Louis, and calling at the Cape of Good Hope on the 8th of July
we arrived off St. Helena. This island, the forbidding aspect of which has been so
often described, rises abruptly like a huge black castle fiom the ocean.

Ascension: 8° S, 14° W

July 19, 1836

On the 19‘” of July we reached Ascension. Those who have beheld a volcanic island,
situated under an arid climate, will at once be able to picture to themselves the
appearance of Ascension. The will imagine smooth conical hills of a bright red
colour, with their summits generally truncated, rising separately out of a level surface
of black rugged lava.

Falmouth, England: 50° N, 5° W

October 2, 1836

. . ..On the 2nd of October we made the shore, of England; and at Fahnouth I left the
Beagle, having lived on board the good little vessel nearly five years. . ..

7l

Appendix II D: Human Variations
Adapted from: http://www.ncsu.edu/scivis/lessons/variation/varlab2.html

The human population exhibits countless variations that result in each individual
being unique. Variations within a population provide the means for natural selection by
affecting the survival rates and reproductive success of individuals within a population.
In this lab we will determine the amount of variation that exists in our small population
by measuring the spread of the hand, and the length of the arm and leg. You must also
measure 2 other variations, on at least 10 people, to be determined by you and your
partner.

Working in groups of four you and your partners will measure hand spread, leg
length, arm length and two other variables that will be determined by your group. You
will then graph the hand spread data for classroom data and determine the mean, median
and mode for the hand spread data.

Materials: Meter stick, ruler, calipers, vernier calipers

1. To measure hand spread make a fist with your thumb and pinky sticking out fi‘om
your fist.

2. Press your fingers down on a metric ruler with your thumb and pinky spread out
as far as possible and record the data in the table below and on the board.

3. Measure the length of your leg by measuring from the outside of the ankle bone to
the top of the hip bone.

4. Measure length of arm from the top of shoulder to the wrist.

5. You and your partners must make measurements of two other variations on 10

 

different people.
Table 1: Hand Spread, Leg Length, and Ann Length Measurements
Hand Spread (cm) Leg length (cm) Arm length (cm)

 

 

 

 

 

 

 

 

 

Table 2: Variations and Measurements
Name Variation 1 Variation 2

 

 

 

 

 

 

 

 

 

 

9P9!"

 

72

Table 3: Hand Spread Classroom Data
cm 10 ll 12 13 14 15 16 17 18 19 20 21 22 23 24

# of
people

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1. Compare the leg length to the arm length of the individuals that you collected data
from. Why would this comparison be of interest to anthropologists?

2. What was the largest hand spread and smallest hand spread measured? What
would be the advantages and disadvantages of large and small hand spread?

3. Why did your group select the two final variations to be measured?

4. What does the mean, median and mode tell us about the data collected?
Mean
Median

Mode

5. What is the significance of having variations within a species such as humans
(Homo sapiens sapiens)?

6. What is the source of the variations that you observed?

73

7. In your own words define variation.

8. In addition to the variations that were observed today list at least 10 other
characteristics that vary in human populations. Try to think of some that are
internal rather than externally visible.

74

Appendix II E: Adaptation of the Human Hand
Adapted from: Labs Online
http://www.troy.kl2.ny.us/thsbiology/labs_online/home_labs/thumb_lab_home.htrnl

Introduction: Living things have structures and molecules that are adapted for the places
they live and the things they do. For example, fish have gills so that they can remove
oxygen that is dissolved in water; most plants have green leaves that contain chlorophyll
to aid in photosynthesis; jellyfish have stinging cells to acquire prey; birds have hollow
spongy bones so that they will be light enough to fly; arctic animals have layers of fat and
thick coats of fur to keep warm in the Arctic climate. Every organism has some type of
adaptation that allows for a successful life.

Humans are also adapted for the things they do. An example of a human
adaptation is our hands. Humans, as well as monkeys, gorillas, and other primates have a
hand that can grasp objects. The opposable thumb makes everyday tasks seem simple, but
what would life be like without thumbs?

Purpose: To demonstrate how the opposable thumb is a human adaptation that we use
daily.

Procedure:
1. You will be given a series of tasks to complete as you normally would.
2. Record the amount of time it takes for you to complete each task in the chart
below.
3. When you have completed each of the tasks, you will lose the use of your thumbs
and complete the tasks again.
4. Using the tape provided, tape your partner’s thumbs tightly to the palm of his or
her hand.
After your thumbs are securely taped, complete the same tasks as before.
6. Record the amount of time it takes for you to complete each task in the chart
below with your thumbs taped to your palms.

i"

 

 

Timed Actions
Action Time with Thumbs Free Time with Thumbs
'Iflred
Tie knot in string

 

Remove and replace
shoe with your hands
Unscrew bottle cap

 

 

Unbutton and re-button
two buttons
Open door

 

 

 

 

 

 

Write your name

 

75

Questions and Analysis:

1.

Compare what life would be like without thumbs to your life now. Do you think
that you would be able to adapt to not having thumbs and perform the tasks as
well in the firture? Why or why not?

Explain why dog and cat paws are not adapted for doing the six actions you
tested. What are cat and dog paws adapted for?

Describe how your hand is adapted for doing the actions you tested and other
actions you perform everyday.

You have an opposable thumb. Explain what you think that means.

List and explain at least two reasons that you feel the human hand adaptations
have helped to make humans such a successfirl species on earth.

Give at least two examples of other adaptations that humans have and explain
why they are useful.

Give at least two examples of adaptations in other species and explain why they
are useful.

76

Appendix II F: When Milk Makes You Sick
Adapted fiom: Therese Passerini
http://www.indiana.edu/~ensiweb/lessons/tp.milk3.htrnl

Introduction: According to statistics, approximately one third of all Americans feel ill
after consuming milk and other dairy products. Parents constantly tell their children to
drink their milk because milk “does a body good.” It is well known that the calcium in
milk helps to build strong teeth and bones. Overall, milk is a good source of nutrients,
like calcium and protein.

Most animals stop drinking milk after they are weaned and their body chemistry
changes so that they can no longer digest the sugar found in milk. Worldwide, this is also
true for the human population. It is actually unusual for adults to be able to digest milk
easily.

Lactose intolerance is the inability to breakdown the sugar found in milk. People
who are unable to breakdown lactose are missing, or have a non-functioning enzyme
called lactase. When lactose intolerant people consume milk, they often feel bloated and
experience gas and diarrhea. As mentioned earlier, most adult animals are not able to
breakdown lactose. Somewhere along the way, some adult humans might have developed
a mutation that allows them to digest lactose as adults.

Purpose: To hypothesize where lactose tolerance might have developed and why, and to
determine the mode of inheritance for the gene.

Part A: Pedigrees

You will make three pedigrees based on each of the scenarios below to determine how
lactose intolerance is inherited. Fill in the circles or squares of individuals that are lactose
intolerant.

Pedigree A

Mike and Donna Miller are both lactose tolerant. They have four children. Fred, Nick,
and Linda are all lactose tolerant. Their daughter Jane is lactose intolerant. Draw the
pedigree for this family below.

Pedigree B
Mary is married to John. Mary is lactose intolerant. They have five children. Ann, David,
and Dan are lactose intolerant. Nancy and Scott are lactose tolerant.

77

Pedigree C

Joe and Lucy Anderson are both lactose intolerant. They have four children: Alicia, Eric,

Ben, and Rodney and all of their children are lactose intolerant.

Analysis of Pedigrees:
1. Does it appear that lactose intolerance is an inherited characteristic? Explain your

answer.

2. How can two parents who are both lactose tolerant produce children who are
lactose intolerant? Explain your answer.

3. What is the most probable mode of inheritance for lactose intolerance? In other
words, is lactose intolerance autosomal or sex-linked, and is it dominant or
recessive. Give reasons for your choices.

4. Draw a Punnett square to support your mode of inheritance for lactose

intolerance.

Part B: Populations and Lactose Intolerance

Graph the information in the charts below that provide percentages for lactose intolerant
populations in different countries. You may use a bar graph. The x-axis should be the
country of origin and the y-axis should be the percentage of lactose intolerance.

Percent of Lactose Intolerant People by Country

 

 

 

 

 

 

 

 

 

 

 

 

Country of Percent Lactose Country of Origin Percent Lactose
Origin Intolerant Intolerant
China 98 Iraq 71

Greenland 85 Russia 16

Mexico 53 Australia 20
Brazil 60 England 15
Italy 55 Kenya 88
South Afiica 95 United States 30
India 60 Nigeria 22

 

78

 

Ethnicity in the United States also plays a part in lactose intolerance. Graph the

information found in the table below in a bar graph. The ethnicity should go on the x-axis

and the percent of intolerance should go on the y-axis.

Lactose Intolerance in the United States

 

 

 

 

 

 

 

 

Ethnicity Percent Lactose Ethnicity Percent Lactose
Intolerant Intolerant

Afiican 75 Eskimos 80

Americans

Asian Americans 90 Hispanic Americans 53

Caucasians 15 Native Americans 90

 

Questions and Analysis:

 

. Formulate a hypothesis as to where lactose tolerance originated and explain why
tolerance would occur here.

2. During the past 5,000 years agriculture has been important to human populations.

In some isolated areas, crops did not perform as well or the climate did not permit
growing crops year round. In these places, animals and their milk were the main
food supply. Use your knowledge of evolution and natural selection to explain
how some populations may have become lactose tolerant.

. What would explain the statistics that approximately 30% of all Americans are
lactose intolerant compared to other parts of the world where that number is more
than 80%?

. Compare the percentages of populations in African countries that are lactose
intolerant. Form a hypothesis to explain why Nigeria is so different from the other
Afiican countries. You should include an explanation with your hypothesis.

. Use the articles on lactose tolerance and evolution available in the classroom, to

gather evidence to support your original hypothesis or formulate a new
hypothesis. Write a paragraph about how scientists think lactose tolerance
evolved.

79

Appendix 11 G: Simulating the Radioactive Decay of Carbon-14
Adapted from Ginny Lambert

Purpose: To understand the concepts of radioactive decay and half-life in the process of
carbon dating.

Materials:

2 pieces of red licorice
1 plastic knife

1 piece of graph paper
1 red colored pencil

1 black colored pencil

Introduction:

Imagine you discover a fossil in your backyard. Although fossils are interesting to
look at, and a lot of information can be gathered just by observing a fossil, it is also
useful to estimate how old the fossil is. All living things consume carbon-l4, which is a
radioactive version of carbon-12. Organic molecules, like proteins, carbohydrates, and
lipids all contain carbon. All of us have carbon-14 in our bodies, and it is constantly
decaying. Radioactive atoms change over time into other types of atoms. For instance,
carbon-l4 decays into nitrogen-14. Carbon-14 can be used to determine the age of
anything that was once living or was made of organic material up to 50,000 years old! All
radioactive materials have a half-life, which is the amount of time it takes for half of a
sample to decay. The half-life of carbon-14 is 5,770 years, but other radioactive atoms
exist with longer half-lives. The ratio of carbon-14 to carbon-12 in living things is
relatively constant when the organism is alive. After death, the carbon-14 continues to
decay, but the amount of carbon-12 remains the same. By measuring the amount of
carbon-14 remaining in a fossil, a bone, or even a piece of cloth, the age of the artifact
can be estimated. In this simulation, red licorice will be used to represent carbon-l4. To
simplify the graphing, we will assume the half-life is about 6,000 years.

Procedure:

1. Turn a piece of graph paper so that it is horizontal instead of vertical.

2. Label the x-axis number of years. The scale will be 1,000 years per line. You
should label the axis up to 55,000 years.

3. Label the y-axis Percent of Carbon-14 remaining. Using the entire y-axis (from
top to bottom), label fi'om 0-100%.

4. Take both pieces of red licorice and lay them on the graph paper at time 0.

5. You need to cut the pieces of licorice so that they are the exact length of the y-
axrs.

6. Mark the top of the licorice at time 0.

7. Lay one piece of licorice on the y—axis, this piece will remain here until the end.

8. Measure the length of your other piece of licorice in centimeters. Record the
number here:

9. Using the knife, cut the licorice exactly 1n half.

'10. Place the half piece of licorice on the 6, 000 year point on the x-axis.

 

80

11.

12.

13.

Draw a line at the top of the piece of licorice. This piece stays on the graph until
the end.

Measure the length of the other half of licorice in centimeters. Record the nrunber
here:

Using the knife cut the licorice exactly in half.

 

14. Place one of the halves of licorice on the 12,000 year point on the x-axis.

15. Draw a line at the top of the piece of licorice. This piece will also stay on the
graph.

16. Continue cutting the licorice in half, placing the pieces on the graph every 6,000
years. Your challenge is to see how many times you can cut the licorice in halfl

17. Once you can no longer cut the licorice in half, connect all of the points with a
line graph, using the red colored pencil.

18. Above the red line, you need to draw a line from each of the intersects to the top
of the graph, using a black colored pencil. This line represents nitrogen-l4, one of

the products of carbon-l4 decay.

19. Once your graph is complete, all of the radioactive licorice may be consumed.

Questions and Analysis:
1. Based on what you have seen in your graph, fill in the chart below with the
percent of carbon-l4 remaining every 5,730 years.

Radioactive Decay of Carbon-14

 

Years
from
present

0

5,730

1 1,460

17,190

22,920 28,650 34,300 40,110 45,840

 

Percent
of
original
carbon-
14 left

 

 

l
0
0

 

 

 

 

 

 

 

 

 

 

2. Describe the problems you had as you approached the last division you did with
the licorice.

3. What do the black lines on your graph represent? Where did this element come

from?

4. Carbon dating is generally useful for dating objects up to about 50,000 years old.
Explain why this method is limited for objects older than 50,000 years and how
you think scientists can date older objects.

81

5. If a 42,000 year old piece of pottery was sold to a museum, how many half-lives
has it existed for? If the original amount of carbon-14 was 1 kg,
how much of the radioactive element is left today?

 

6. If you have a fossil with only 30% of the original radioactive carbon-l4
remaining, how old is the fossil?

7. Ask the teacher for your fossils. You will be given 3 licorice fossils that you must
date using your graph. Place your fossils on the graph and find where they
intersect the curve and estimate the age of each fossil. Mark each fossil on your
graph. Record the ages of the fossils below from youngest to oldest.

Fossil l

 

Fossil 2

 

Fossil 3

 

8. In 1991, a prehistoric man, Otzi, was discovered. The prehistoric man was frozen
in time by glaciers. Carbon dating of the samples from the site established the
time of Otzi’s death at approximately 5,300 years ago. What percentage of the
original carbon-14 in the body was remaining in 1991?

9. While studying the nature of past climates, scientists in 1998 pulled to ice cores
from the bottom of a glacier. Trapped within the cores were insects and bark
fiagments fiom local trees. Carbon fi'om organic material near the bottom of the
cores dated to the coldest period of the last ice age. If those samples had 5.5
percent of their original carbon-l4 remaining, approximately how many years ago
did the glacier form?

10. The authenticity of the Shroud of Turin has long been debated. In 1988, scientists
removed small samples for carbon dating. Three different labs analyzed the

samples, and all three found that approximately 8 percent of the carbon-14 atoms
had decayed. Using this information, how old is the shroud?

82

Appendix [I H: Fossil and Migration Patterns in Early Hominids
Adapted from John Banister-Marx
www.teachersdomain.org/resources/tdc02/sci/life/evo/Ip_bumanevo/index.btml

Introduction:

Discoveries of fossil hominids around the world have helped scientists to
determine not only a likely origin for human species, but also a migration pattern
throughout the world. Until the 1920's, Asia had been considered the birthplace of
humans. Yet one man stood alone in his conviction that Asia was not the birthplace of
humankind. Louis S. B. Leakey searched the weathered desert slopes of Olduvai Gorge
for several decades, looking along what had been prehistoric shores of an ancient lake
looking for hominid fossils. Eventually his efforts paid off when he confirmed finding
early hominid fossil remains. Since then, other fossil hominids have been discovered
throughout much of the world. It is the type, dates and distribution of these fossil
specimens that gives us an indication of where humankind's earliest ancestors had
migrated and originated.

Purpose:

Using knowledge of geography and mapping skills, students will determine the
location of a sampling of fossil hominids to infer a continent of origin and a likely pattern
of migration fi'om that point of origin.

Procedure:

Examine the data below and plot each coordinate. Though this list is not an
exhaustive list of all the fossil hominid discoveries, it is accurate in terms of general
trends of distribution and density within given regions. Mark your map by using red
numbers for Australopithecines (1-10), blue numbers for Homo erectus (1 1-22), green
numbers for Homo sapiens neanderthalensis, and black numbers for Homo sapiens
sapiens. Write the numbers directly on your map using colored pencils.

Data:
The data below includes four pieces of information:
9. Fossil taxon and its age range in millions of years
10. Location in degrees east or west longitude and north or south latitude, and the name
of site where fossil was found

83

Australopithecines (4.4-1.4 MYA) Fossils 1-10

 

1) 38°E, 1°S Chemeron

5) 36° E, 5° S Laetoli

9) 27° E, 27° 8
Swartkrans

 

2) 27°E, 27°S Sterfontein

6) 36° E, 7° N Omo

10) 38° E, 4° N Koobi—
Fora

 

3 43° E, 8°N Hadar

7) 26° E, 26° S Kromdrai

 

 

4) 37° E, 4° S Olduvai

 

 

8) 28° E, 25° S Magapansgat

 

Homo erectus (1.9-.3 MYA) Fossils 11-22

 

11)112°E,38°N

15) 38° E, 4° N Koobi-For a

19) 27° E, 27' s

 

Zhoukoudian Sterkfontein
12) 112° E, 8° S 16) 6° W, 35 °N Sale 20) 43° E, 8° N Nhadar
Modjokerto

 

13) 18°E, 18°NYayo

17) 13° E, 47°N Mauer

29 37° E, 4° S Olduvai

 

 

14) 7° W, 34°N Rabat

 

 

18) 27' E, 27' S Swartkrans

22) 36° E, 7°N Omo

 

Homo neanderthalensis (.13-.03 MYA) Fossils 23-45

 

23) 36° E, 33°N Amud

31) 11° E, 47° N Steinheim

39) 36° E, 35° N

 

 

Tabun

24) 110° E, 7° S Solo 32) 7° E, 52°N Neanderthal 40) 24° E, 30° S
Florisbad

25) 8° E, 32° S Saldanha 33) 34° E, 45° N Kiik-Koba 41) 138° E, 34° S Lake
Mung)

 

26) 27° E, 32° S Broken
Hill

34) 5° w, 32° N Jebel-Irhoud

42) 115° E, 1°N Niah

 

27) 68° E, 41° N Teshik
Tash

35) 38° E, 50° N Sungir

43) 112° E, 38°N

 

 

28) 5° W, 35°N Gibraltar 36) 3° E, 35°N Swanscombe 44) 99° W, 19°N
Tepexpan

29) 44° E, 36° N Shanidar 37) 18° E, 48° N Predmost 45) 112° E, 38° N
Zhoukoudian

 

30) 2° W, 52° N
Swanscombe

 

38) 70' E, 62° N

 

 

 

Early modern Homo sapiens (.1-.02 MYA) Fossils 46-56

 

46) 75° w, 2°N Punin

50) 108° E, 27°N

54) 88° W, 32° N
Natchez

 

47) 120° W, 44° N
Marmes

51) 32° E, 27° S Border Cave

55) 102° W, 32°N
Midland

 

48) 100' E, 54° N

52) 35° E, 32°Jebel Qafzeh

56) 81°W, 27°N Vero
Beach

 

49) 70° E, 23° N

 

 

53) 44° W, 18° S Lagoa
Santo

 

 

84

 

 

 

 

Questions

1. How many thousands of years ago is 1.3 million years? Or .02 million years?

2. Why have scientists concluded that Africa is the “birthplace” of hominids?

3. Find a fossil and write its type (taxon) and map coordinates for each of the
following locations listed below.
Location Fossil Type
United States
Central America
South America
Australia
Asia
Afiica
Europe

4. Which taxon seems to have the smallest range of distribution?

5. Which taxon seems to have the largest range of distribution?

6. Explain how you think that the hominids got to all of the different places.

7. In which area does Neanderthal seem to be most prominent?

8. Describe the overall pattern of hominid migration based on the data that you
plotted.

85

Appendix II I: Laetoli Footprints: Analyzing Fossilized Footprints
Adapted from: J oselyn Burnaby
Kent City High School

Introduction: In 1976, a 3.6 million-year-old set of hominid footprints were discovered
in Tanzania that were preserved by volcanic ash. They were discovered by Andrew Hill
and a colleague when they were throwing elephant dung at each other. Hill dove out of
the way and landed on the tracks. Since then, the footprints have provided insight into
early bipedal ancestors of humans.

Purpose: To analyze foot length, stride length and height of modern man and compare
these measurements to the Laetoli footprints to calculate early hominid height.

Procedure:
You will gather a classroom set of data to determine if there is a relationship between
foot length, leg length, and height. You will also measure your stride while walking and
running.
1. Measure your foot length, leg length, and height in centimeters and record in the
data table.
2. Graph the footprint size vs. height for the entire class. Footprint size on the x-axis
and height on the y-axis.
3. Draw a line of best fit thru the data points on your graph.
4. Measure and mark off a distance of 2000 cm (20m).
5. Walk the length while counting the number of strides (Nw). Record Nw in the

data table.
6. Run the length while counting the number of strides (Nr). Record the Nr in the
data table.
7. Calculate the stride length (S) by dividing by the distance (2000 cm) by the
number of strides (N).
Sw = 2000cm + Nw Sr = 2000 cm -I- Nr

8. Graph the relationship between leg length and stride length. Leg length should go
on the x-axis and stride length should go on the y-axis.
9. Calculate the ratio of your stride length to leg length (S/L) and record in the data
table.
S/L = Sw -=- Leg length
10. Calculate the ratio of stride length (S) to height (S/H) and record in the data table.
S/H = Sw + Height
11. Measure the footprint sizes from the model of the Laetoli footprints and record in
Data Table 2.
12. Calculate the average size for the smaller individual and the average size for the
larger individual. Record in Data Table 2.
13. Using the best-fit line graph from the class data, determine how tall the
individuals might have been based on their footprint size.
14. Measure the distances between the strides and calculate the average stride
distance for each individual and record in Data Table 2.

86

Conclusions and Analysis
1. Do you see a pattern on the stride graphs? Explain your answer.

2. Determine if foot length can be used to predict height. To test this hypothesis,
measure a person’s foot length and use your graph to predict his or her height.
Now, measure the height of that person. How close was your prediction to the
actual height? Explain whether or not foot length can be used to predict height.

3. Paleontologists use the ratio of stride length divided by leg length (S/L) to tell
whether a dinosaur is walking, trotting, or running. The following values are used
to determine how a dinosaur might have been moving:

Less than 2 = walking 2-2.9 = trotting More than 2.9 = running
Examine the class data for the ratios of stride to leg length (SW/L and Sr/L) to
determine if the values used for dinosaurs also apply to people. If not, what values
would change? Explain your answer.

4. If a person’s footprints were discovered in someone’s backyard, explain what
information could be determined about the person who made the footprints? What
information about the person could not be determined fi'om the footprints?

5. Explain why you counted your strides over a 2,000 cm length rather than make
only one stride measurement.

6. Below is a series of footprints found in the mud outside of school. Based on the
measurements given, calculate the leg length and height of the person. Who do
you think the footprint belongs to?

Foot length = 29 cm Stride length = 160 cm

Estimate how tall the person is and what the person was doing when the footprints
were made.

87

Appendix II J: Chronology of Hominids
Adapted from: Chronology Lab by Larry Flarnmer
http://www.indiana.edu/~ensiweb/lessons/chronlab.htrnl

Introduction: As more discoveries are made, the fossil record for hominids is becoming
more complete. Hominids include humans and their two-legged primate ancestors. With
the addition of more information, the gaps in the fossil record are starting to show a more

complete history of early man.

Purpose: To create a timeline of hominid fossils to show the changes in hominids over

time.

Procedure:

1. Start with the oldest fossil in the chart below (A. ramidus), and draw a vertical
line near the lower left comer on the chronology chart. The vertical line should
start at 4.6 million years ago (mya) and end at 4.2 mya. Write the name of the

fossil next to the vertical line.

2. For each of the remaining species, shift about a centimeter to the right each time

and plot the vertical lines on the chronology chart.

3. Estimate as closely as possible the positions to plot which fall between the lines

on the chronology chart.

A e of Fossils

 

Species/Sub-species

Lived. . .Years Ago

 

Homo sapiens
Cro-Magnon ......................
Neanderthal .......................
Archaic H. sapiens ..............

50,000-10,000
l 25,000—3 0,000
700,000-250,000

 

Homo erectus

1.8 mya — 300,000

 

 

 

 

 

Homo habilis 2.5 mya — 1.5 mya
Australopithecus boisei 1.8 mya — 1.4 mya
A. robustus 2 mya — 1.5 mya
A africanus 3 mya — 2.3 mya
A. afarensis (Lucy) 3.9 mya — 3 mya

 

A. anamensis

4.5 mya — 3.0 mya

 

 

Ardipithecus ramidus

 

4.6 mya — 4.2 mya

 

88

 

Chronology Chart
MYA

 

Now

 

 

 

ixbxhiu

 

 

1.2

 

1.4

 

1.6

 

1.8

 

2.0

 

2.2

 

 

2.4

 

2.6

 

2.8

 

3.0
3.2

 

3.4

 

3.6

 

3.8

 

4.0

 

4.2

 

4.4

 

4.6

 

4.8

 

5.0

 

89

Appendix II K: Bead Bug Blitz
Adapted from Merle K. Heidemann
Science and Math Education Professor, Michigan State University

Introduction: A population is a group of interbreeding organisms that exist within a
known range. Natural variation exists among the organisms in a population, and selection
pressures can cause certain individuals in a population to have an advantage over other
individuals. A classic example of this is the peppered moths. There are two morphs of
peppered moths, a light and a dark morph. Peppered moths live in England and rest on
trees that are nearly the same color as the light morph peppered moth. Predators can
easily find the dark morphs against the light background of the tree, so very few of the
dark morphs survive to produce offspring. However, when the industrial revolution hit
England, ash in the air from the coal-burning factories caused some of the lightly colored
trees to become gray. In response, the light colored peppered moths were very easy to
spot, so very few of the light morphs survived to reproduce. As a result, the dark
peppered moths became more numerous because they had better camouflage and blended
in with the darker trees. This example shows that populations can change over time as a
result of selection pressures.

Purpose: To explain how genetic variation and environmental pressures contribute to the
diversity of organisms and how natural selection acts on individuals, causing changes in
populations over time.

Materials:

3 populations of colored beads (approximately 50 beads of each color)
2 fabric “habitats”

3 cups

Scenario: There exists a patch of land known as Multicolored Meadows. In the Meadows,
there are small critters known as Beadbugs, who come in a variety of colors. The
Meadow Muncher is a natural predator of Beadbugs. Today, you will become the
Meadow Muncher and devour the tasty Beadbug in its natural habitat. You will be
monitoring the different populations of Beadbugs for several generations to see if any
change occurs.

Procedure: Read all directions before beginning!

1. Form a group of three.

2. Assign the following roles in your group: Meadow Muncher, Recorder, and
Beadbug Reproduction Manager. You may swap duties when you change the
habitat later.

3. Choose two types of habitats for your Beadbugs. The habitats come in the form of
patterned material.

4. Choose three colors of beads to represent your Beadbugs. The colors should
roughly match the colors of your first habitat. In other words, your beads should
blend in to the background.

5. Gather about 50 bead of each color and place each color into a separate cup.

90

 

 

 

 

 

 

6. Take all of your materials back to your lab station.

7. Lay down your first habitat and everyone but the Meadow Muncher should evenly
place 16 beads of each color on the fabric.

8. Record in your data table the number of beads of each color in Generation 1.

9. Now it is time for the Meadow Muncher to start catching Beadbugs, but there are
some rules to follow:

a. The Meadow Muncher can only pick up one bead at a time.

b. The Muncher must take the first bead that he or she secs.

0. After picking up a bead, the Muncher must look away before picking up
another bead.

10. The Muncher must eat 24 beads.

11. After the feeding, the number of each color Beadbug must be counted and
recorded in the data table.

12. Take the initial population and subtract the number eaten to find the number of
survivors for each color.

13. The Beadbugs who survive get to reproduce. Each parent produces one offspring
identical to it. The Beadbug Reproduction Manager must double the number of
survivors of each color and place the offspring in the habitat. For example, if 6
red Beadbugs survived, there would be 6 red offspring, for a total of 12 red
Beadbugs at the beginning of the next generation.

14. Record the initial population for the next generation. This number should be two
times the number of survivors from the previous generation.

15. Continue to eat, reproduce, and record the information for five generations of
Beadbugs.

16. At the end of five generations, the Beadbugs are forced to move to a new habitat
due to a drought. Move your Beadbug population to your other habitat.

17. Continue to use the same procedure for five generations on the new habitat.

First Round
Habitat Descri ation
Generation Color: Color: Color:
Initial Population: _ Initial Population: _ Initial Population: _
1 Number Eaten: Number Eaten: _ Number Eaten:
Survivors: Survivors: Survivors:
Initial Population: _ Initial Population: __ Initial Population: __
2 Number Eaten: Number Eaten: _ Number Eaten:
Survivors: Survivors: Survivors:
Initial Population: ___ Initial Population: __ Initial Population: _____
3 Number Eaten: Number Eaten: __ Number Eaten:
Survivors: Survivors: Survivors:
Initial Population: Initial Population: __ Initial Population:
4 Number Eaten: Number Eaten: _ Number Eaten:
Survivors: Survivors: Survivors:
Initial Population: Initial Population: _ Initial Population:
5 Number Eaten: Number Eaten: __ Number Eaten:
Survivors: Survivors: Survivors:

 

 

 

 

 

91

 

Second Round
Habitat Descri tion

 

 

 

 

 

 

 

Generation Color: Color: Color:
Initial Population: __ Initial Population: _ Initial Population: __
1 Number Eaten: __ Number Eaten: _ Number Eaten: __
Survivors: Survivors: Survivors:
Initial Population: __ Initial Population: _ Initial Population:
2 Number Eaten: __ Number Eaten: __ Number Eaten: _
Survivors: Survivors: Survivors:
Initial Population: __ Initial Population: _ Initial Population: __
3 Number Eaten: _ Nrunber Eaten: _ Number Eaten: __
Survivors: Survivors: Survivors:
Initial Population: _ Initial Population: _ Initial Population:
4 Number Eaten: __ Number Eaten: _ Number Eaten: __
Survivors: Survivors: Survivors:
Initial Population: __ Initial Population: __ Initial Population:
5 Number Eaten: __ Number Eaten: _ Number Eaten: __
Survivors: Survivors: Survivors:

 

 

 

 

 

Questions and Analysis:

1.

Did any specific color of Beadbug go extinct? If so, explain why extinction
occurred using the concept of natural selection. If no extinction occurred, explain
why all colors survived using the concept of natural selection.

Was there a change in the distribution of Beadbug colors when you switched
habitats? Explain what this change in habitat represents in the real world.

If you started with a population of only green Beadbugs, would you see any
change take place in this population over time? Why or why not?

If you only had green Beadbugs, explain whether or not this population would be
able to adapt in the future if the organisms had to change habitats again.

Predict what the population of Beadbugs in the second habitat would look like in
10 generations. Explain why you think the population may or may not change.

92

Appendix [I L: Clipbirds
Adapted fiom: A1 Janulaw and Judy Scotchmoor
http://www.ucmp.berkeley.edu/education/lessons/clipbirds/

Overview:
This activity will demonstrate how variation in bird beaks within a population varies
from generation to generation based on the available food types.

Purpose:
To show variation and natural selection within a population, adaptations that are
advantageous persist in a population, and speciation requires reproductive isolation.

Introduction:

Evolution is the result of natural selection acting upon variation within a population.
Given a set of environmental circumstances, organisms with favorable traits have a
selective advantage over individuals with less favorable traits. Selective advantage leads
to speciation. It is important to understand that favored traits are only advantageous
within a particular situation and may not aid in survival if the circumstances change. For
Clipbirds, different types of food favor different beak sizes. One beak size may only be
favorable over another beak size under specific conditions. When conditions change, the
favored beak size may also change.

Materials per group:

3 bags filled with “food” for each season
10 large binder clips

10 medium binder clips

10 small binder clips

10 plastic cups

Scenario:

In a land far, far away, there is an island known as Clipland. The island is inhabited by a
large population of Clipbirds that feed on a variety of foods. The Clipbirds recently had a
major disagreement about the mating season, and part of the population re-located to the
other side of the mountain range that divides the island. The two populations now live
separately because of their differences. Now, the two populations are known as the East
and West Clipbirds.

Procedure:

1. The room will be divided in half, and you will be working with the people on
your side of the room.

2. Before starting, predict which beak will be the most fit for survival for the three
seasons described in Table 1. You should look at the energy values for each food
type and at each of the bird’s energy requirements for survival and reproduction.

3. Choose six people to begin as the Clipbirds.

93

4. Two of the six people will be given large clips, two will be given medium clips,

and the remaining two will be given small clips.

Each of the Clipbirds must also have a plastic cup that represents the stomach.

Spread out the food the first season in the pan provided.

Each Clipbird has different energy requirements to survive, and additional energy

is needed to reproduce. See Table 2 for the caloric values of the food and Table 3

for the survival and reproduction energy needs for each bird type. Keep in mind

there is a competition between the east and west Cliplands to see which
population will become the largest. When there is enough energy to reproduce,
one offspring is made that is identical to the parent.

8. The entire population will have 30 seconds to eat all that they can, at the same
time, but remember each of the various food types have a different caloric value.

9. To gather food, the “beaks” are opened, the food is grasped, the “beak” is closed,
and the food is deposited in the stomach.

10. At the end of each feeding, the number of calories must be calculated and the fate
of the bird must be recorded in Table 3. The number of birds that survive and the
nrunber of Offspring for each season will be recorded. Students who were not part
of the original six birds, will become the offspring for seasons 2 and 3. Birds that
do not survive, are eliminated from the population, but may become offspring in
future seasons.

11. After Season 1 is completed, retrun all of the food to the bag.

12. Pour the bag labeled Season 2 into the container and repeat steps 7-10.

13. At the end of Season 2, return all of the food to the bag.

14. Pour the bag labeled Season 3 into the container and repeat steps 7-10.

15. Record the initial populations and the end total population for the East and West
Cliplands on the board for each season and each bird beak.

>193"

T pes and amounts of food available each season

 

 

 

 

Location Season 1 Season 2 Season 3
4 cups popcorn 1 cup popcorn
East Clipland 2 cups lima beans 20 lima beans 100 marbles
50 marbles 50 marbles
4 cups popcorn 4 cups popcorn
West Clipland 2 cups lima beans 20 lima beans 6 cups of
50 marbles 5 marbles popcorn

 

 

 

 

 

Predict which bird beak will be the most successful in each season, and explain why you
think that way.
East Clipland Season 1:

East Clipland Season 2:

East Clipland Season 3:

94

West Clipland Season 1:

West Clipland Season 2:

West Clipland Season 3:

Based on your predictions, describe what you think the population on each side of the
island will look like at the end of the third season. Explain why you think your
predictions are likely.

East Clipland:

West Clipland:

Food Values in Kilocalories

 

 

 

 

 

Food Type Energy (Kilocalories)
Marblefruit (Marble) 10

Big Tootfi'uit (Lima beans) 5

Tiny Tootfruit (Popcorn) 2

 

 

 

Kilocalories Needed for Survival and Reproduction

 

 

 

 

Type of beak Kilocalories needed Kilocalories needed
to survive to reproduce

Large beak 100 200

Medium beak 60 120

Small beak 35 70

 

 

 

 

 

95

Clipbird Population

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Season 1 Season 2 Season 3

Small Initial Population Initial Population Initial Population
Survivors Survivors Survivors
Offspring Offspring Offspring
Total moving to Total moving to Total at end
Season 2 Season 3 _

Medium Initial Population Initial Population Initial Population
Survivors Survivors Survivors
Offspring Offspring Offspring
Total moving to Total moving to Total at end
Season 2 Season 3 _

Large Initial Population Initial Population Initial Population
Survivors Survivors Survivors
Offspring Offspring Offspring
Total moving to Total moving to Total at end
Season 2 Season 3 _

Questions and Analysis:

1. On a separate piece of paper, graph the initial populations and the end total

population for the small, medium, and large beaks for each season and for both
sides of the island. The seasons are on the x-axis and the number of birds should

go on the y-axis. All of the information should be put on one graph.

2. What does the graph show is happening to the population of birds in East
Clipland? Explain what you think caused the changes seen in the graph.

3. What does the graph show is happening to the population of birds in West
Clipland? Explain what you think caused the changes seen in the graph.

96

 

. Determine which beak size was the best adaptation for each of the seasons in East
Clipland.
Season 1 Season 2

 

 

Season 3

 

. Compare your predictions with your results for East Clipland. Were the
predictions the same as the results? Why or why not?

. Determine which beak size was the best adaptation for each of the seasons in
West Clipland.
Season 1 Season 2

 

 

Season 3

 

. Compare your predictions with your results for West Clipland. Were the
predictions the same as the results? Why or why not?

. Define natural variation. Give at least two sources of natural variation found in

this simulation.

. Explain the role of the mountain range on the island. In other words, how does the
mountain range effect the population of birds?

10. After three seasons, explain whether or not you think speciation is occurring

between the two populations of clipbirds. Give evidence to support your claim.

1 1. What type of speciation do you think is occurring on Clipland? Explain your

answer.

97

Appendix II M: Molecular Sequencing of Amino Acids
Adapted from: Craig Nelson and Martin Nickels
http://www.indiana.edu/~ensiweb/lessons/mol.prim.html

Purpose: In this activity, you will analyze the amino acid sequence of beta hemoglobin
molecules of eight different species to determine how closely the species are related. You
will also construct a cladogram and graph the similarities.

Introduction: For many years, organisms have been classified based mainly on their
visible characteristics. Organisms that are in the same genus are more closely related than
all of the organisms in the same kingdom. The fossil record shows that the types of
organisms on earth have changed dramatically over millions of years. However, the
change is gradual, and indicates that common ancestors connect all life forms to each
other. When tracing the flow of life back deep in time, many examples of gradual
changes from earlier times can be seen. This leads to the understanding of descent with
modification.

In addition to structural similarities and the fossil record, DNA and proteins can
be used to determine patterns of ancestry and how organisms are related. In fact, many
organic molecules can be used to determine the degree of similarity.

Procedure Part A:

1. On the Data Sheet you will find an amino acid sequence for beta hemoglobin for
eight different species. To save time and space, only the amino acids that are
different have been listed.

2. Compare species A with species B. Count the number of differences you see
between the two sequences and record this number in the matrix below.

3. Compare Species A with species C. Count the number of differences you see
between the two sequences and record this number in the matrix below.

4. Continue comparing the species and counting the number of differences seen in
each sequence and recording them in the matrix below.

5. Calculate the average number of differences for each species and record.

Note: The S In the matrix below means the same species were compared, so there are

obviously no differences. The X represents comparisons that overlap 1n the matrix.

Part “A” Matrix: Differences Amon Amino Acid Se uences

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Species A B C D E F G
A S 25
B X S 25
C X X S 24
D X X X S 23
E X X X X S 22
F X X X X X S 25
G X X X X X X S
H X X X X X X X
Averags ----- 24

 

****Averages must be rounded to the nearest whole number.

98

Questions and Analysis for Part A:
1. What does the S represent in the matrix? In other words, what two species are
being compared? How many differences would you expect for this comparison?

2. What two species are the most closely related? How can you tell?

3. What two species are the least closely related? How can you tell?

4. What is the general pattern of differences among the column averages as you
move from left to right across the table? What does this suggest about the
relationships of each species?

Part B

1. The first seven species in the data table and matrix are primates.

2. Label each of the species A-G with their names in the matrix according to the
table below:

 

 

 

 

 

 

 

 

 

 

Sgecies A Human Species E Rhesus Monkey
Species B Chimp Species F Squirrel Monkey
Species C Gorilla Species G Lemur
Species D Gibbon

Questions:

1. Are gorillas more similar to humans or to chimpanzees based on the sequence
data? Why?

2. Explain what you think the similarities between the species indicate about a
common ancestor?

Part C: Building a Cladograrn

Cladistics is a classification scheme that assumes every group of organisms arose by
branching off from a previous group. Each branch is called a clade. That clade
includes any and all subsequent branching. One clade often includes many smaller
clades. All the individuals within a clade share one or more selected traits. Each trait
must be identical or very similar within a clade. However the traits appear to be
modified from earlier forms of the trait. The simplest diagram showing the branches
is based on the sequence of modifications and produces a cladogram.

99

 

Species

G

 

Species

F

 

Species

E

 

Species

D

 

Species

C

 

Species

B

 

Species

A

 

 

Amino

Acid
Position

 

 

 

 

 

 

 

 

10
12
13
16
20
21

 

 

 

 

 

 

22
33

 

 

43

 

50
52
54
56
69

 

 

 

 

 

70
72
73

 

 

 

75

 

76
87
94
95

 

 

 

 

104

 

112

 

116

 

120

121

 

 

123

 

125

 

126

 

129

 

130

 

135

 

 

Data Table: Comparison of the Amino Acids in the Beta Chain of the Hemoglobin

Molecule in Eight Selected Species

100

Appendix II N: Creating Phylogenic Trees using Carninalcules
Adapted fiom Robert P. Gendron
Indiana University
Introduction:

This exercise introduces the process of classification and the development of a
Phylogenic tree based on the physical characteristics of Carninalcules. Carninalcules
have an extensive fossil record that has been collected by many scientists throughout the
world. You and your partner have been asked to assist in developing a Phylogenic tree
based on the fossil evidence and several currently surviving species of Carninalcules. As
you develop your Phylogenic tree please keep notes on the characteristics that you used
to develop your tree. You will later be asked to compare your classification tree to those
of other researchers in your classroom. Your notes will assist you in defending your
Phylogenic tree. Please keep in mind that there may be many possible ways of
developing a phylogenic tree for a given set of data.

About The Carninalcules:

The Carninalcules are artificial animals created by the late Professor Joseph Carnin of the
University of Kansas. They were developed to study how taxonomist classify real
organisms.

Materials: Scissors, rulers, poster board, tape, Carninalcules

Procedures:

11. Cut out the 14 currently living species of Carninalcules and 57 fossilized species
of Carninalcules.

12. Each Carninalcules is identified by a number, which corresponds to an individual
species.

6. The number in parentheses indicates the age of the fossil which was determined
by radiometric dating.

3. On poster board draw horizontal lines. Each line will represent 1 million years.
On the bottom you will place the oldest specimen at 19 million years ago.

4. You should place the Carninalcules onto the poster board on the corresponding
dates. Organisms that look alike should be placed above their ancestors to show
the evolutionary lines of descent.

5. As you move upward, toward the present, attempt to determine the relationship of

the newer species to the older species. Pay close attention to the characteristics
that were used in determining the relationship fi'om one species to the others.

101

6. Use horizontal lines to connect species of Carninalcule that are related. Be able to
justify your reasoning for these relationships.

7. Compare your Phylogenic with others within the classroom. Openly discuss and
share your ideas on each Phylogenic tree.

8. When finished answer the questions and turn in your phylogenic tree making sure
to tape your Carninalcules to the poster board.
Questions
1. What does your phylogenic tree represent?

2. If two Carninalcules are related in your classification, or appear close
together, what does that mean?

3. Which Caminalcule fossil is the oldest? What characteristics does it have?

4. Which Carninalcule is most closely related to nrunber 9 and number 7 and
why?

5. What may have occurred to number 34?

6. What is the common ancestor to number 20? Why do you think this?

7. If scientists wanted to test this hypothetical phylogenic tree, what other
evidence could be used to analyze the relationships between Carninalcule ?

8. Are any of the Carninalcules dead end lineages or went extinct? What
could have occurred to cause this extinction?

9. Write a paragraph explaining how you developed your phylogenic tree and
what characteristics were used.

102

Appendix 11 O: Jumping Frogs: Selecting for Phenotypes
Adapted from: Holt High School Biology Department

Introduction: Variation exists within all populations of organisms, meaning not all
individuals look the same. The differences seen in an individual are the result of gene
shuffling due to sexual reproduction, crossing over during meiosis, and mutations. Most
people associate natural selection as the mechanism that drives evolution, but the changes
in genes and gene frequencies caused by mutations and sexual reproduction are the raw
materials for natural selection. Natural selection does not act directly on genes. Instead, it
acts on phenotypes, or the physical characteristics of an organism. Phenotypes that are
more fit, survive to reproduce. Natural selection determines what genes are passed from
one generation to the next based on phenotypes.

Purpose: To show that natural selection acts on phenotypes to change the allele
frequencies in a population.

Materials:
- 5 x 5 sheets of paper (small fiogs)
- 8 x 8 sheets of paper (large frogs)
- Dice
- Origami handout
- Meter stick
- Ruler

Post-it Notes

Scenario: A nuclear power plant has been built near the habitat of a population of fiogs.
The recent addition of the power plant has made food scarce, and the frogs now have to
jump over a barrier to find food. On the other side of the barrier, there are several
predators that happen to enjoy frog. So, not only do the frogs have to jump over the
barrier to survive, they must also escape the predators. Currently, the frogs come in two
sizes: large and small. The frogs can also be spotted or have no spots. Frogs without spots
are easier for predators to find. You will be monitoring the fi'og population and changes
to the size and spots of the frogs over several generations to see if the nuclear power plant
has any affect on the fiog population and to determine if evolution is occurring in the
population.

Genetic Information

The size of the frog is determined by one gene. The small phenotype is dominant over the
large phenotype. Write the genotypes below for the size of a frog. Use the letter g to
represent the allele for size.

Small Small Large

 

 

 

Spots are also controlled by one gene. The absence of spots is dominant over the presence
of spots. Write the genotypes below for spots on a frog. Use the letter a to represent the
allele for spots.

103

Spots Absent Spots absent Spots
Questions:
1. What would a frog look like that had the genotype Gg?

 

 

2. What would the genotype be for a frog with spots? How do you know?

3. What would a fi'og look like if it had the following genotype: ggAa?

4. Predict which size frog you think will be able to jump further and higher. Explain
why you think that Size frog will be the best.

5. Before beginning, predict whether you think frogs with spots or frogs without
spots will be able to avoid predators better. Explain why you think spots or no
spots will be more fit.

Procedure:
1. Flip a coin to determine the genotypes and phenotypes of your frog. You will
need to flip the coin four times to determine the genotypes for both traits.

 

 

 

Heads = G, A
Tails = g, a
Trait Allele 1 (Flip 1 Allele 2 (Flip 2 Genotype Phenotype
for traitL for trait)
Size
Spots

 

 

 

 

 

 

 

2. Make a frog according to your genotypes, using the origami handout.

3. Record the phenotypes of all the frogs at your group in the Generation 1 Table as
the initial population.

4. Take a small sticky note and write the genotype of your frog on it and stick it to
your frog.

5. Lay the meter stick across your table and flip it on its side so that it is standing up
and no longer lying flat. The meter stick represents the barrier the fi'og has to
jump over.

6. Measure 25 cm fi'om the meter stick, and place a piece of masking tape here. This
will be the starting line that the frogs must jump from.

7. Line your frog up at the starting line and push on the frog’s “legs” to make it
jump. If your fi'og makes it over the barrier, it survives the first obstacle. Frogs
that do not make it over the barrier starve to death and are no longer part of the
population.

104

8. Once on the other side of the barrier, the dreaded dice predators exist.

9. You need to a roll a die to determine whether your fiog evades being eaten by a
predator. The chances of survival are different for spotted and non-spotted frogs.
Use the table below to determine whether your frog survives based on the number

 

 

you roll.
Spots 1-5 Survive 6 die
No spots 1-3 Survive 4-6 die

 

 

 

 

 

10. Record the number of survivors for each phenotype in the Generation 1 Table.
11. If your frog survived, you need to find a partner to reproduce with in your group.
Your frog can reproduce with any other fi'og because they are all the same

species.
12. Using the genotypes of the parents, draw a Punnett square for both traits.
Size: Spots:

 

 

 

 

 

 

 

 

 

 

 

 

13. Due to the nuclear power plant, the frogs only produce one offspring per mating.
Tear off four pieces of paper and number them 1-4. Fold them in half and draw a
number. The numbers correspond to the genotypes in the Punnett squares. You
will have to draw two numbers, one for each of the traits.

1 2

 

 

3 4

 

 

 

 

14. Make your offspring, and record its phenotype in the Generation 1 Table, along
with all other offspring made in your group.

15. Starting with step 6, repeat the experiment using the parents that survived and the
offspring for three more generations.

16. Save all your frogs because they may be re-used as offspring and we will be using
them later.

Generation 1 Table

 

 

 

 

 

 

Frog Phenotype Initial Number that Percent Offspring Survivors
Population Survive of plus
Size Survival Offspriri
Small without spots
Small with spots
Large without spots
Large with Spots

 

 

 

 

 

 

 

105

Generation 2 Table

 

Frog Phenotype

Initial Population
Size

Number that
Survive

Percent of
Survival

Offspring

Survivors
plus
Offspring_

 

Small without
spots

 

Small with spots

 

Large without
spots

 

Large with Spots

 

 

 

 

 

 

 

 

Generation 3 Table

 

Frog Phenotype

Initial Population
Size

Number that

Survive

Percent of
Survival

Offspring

Survivors
plus
Offspring

 

Small without
spots

 

Small with spots

 

Large without
SQ“

 

 

Large with Spots

 

 

 

 

 

 

 

Generation 4 Table

 

Frog Phenotype

Initial Population
Size

Number that
Survive

Percent of
Survival

Offspring

Survivors
plus
Offspring_

 

Small without
spots

 

Small with spots

 

Large without
spots

 

 

Large with Spots

 

 

 

 

 

 

 

1. Graph the initial population of fiogs for each generation. The generations should
go on the x-axis and the number of individuals should go on the y-axis. You need
to use four different colors to represent the different types of frogs. Everything
should fit on one piece of graph paper.

2. Which size of frog proved more fit for the environment? Why?

3. Were spotted fi'ogs or non-spotted frogs better adapted to the environment? Why?

4. Describe what the selective pressures were for the fiogs. In other words, what
determined whether a frog survived or not.

5. Explain what you think the population of fi'ogs will look like in 10 generations, if
nothing else in their habitat changes.

106

6. Were any of the phenotypes eliminated from the population? If so, which
phenotype was no longer present in the population and why did it disappear? Did
the phenotype ever re-appear? Why or why not?

7. Were any of the alleles (G or g) eliminated from the population? If so, which
allele was no longer presenting the population and why did it disappear?

8. Is evolution occurring in this population of frogs? Give evidence to support your
answer.

107

Appendix II P: Mutated Frogs: Are Mutations Always Bad?
Adapted from: Holt High School Biology Department

Introduction: Gene shuffling from sexual reproduction and mutations are the two main
driving forces of natural selection. In the previous exercise, you saw how natural
selection works on phenotypes, and how genotypes change. Today, we are going to be
working with jumping fi'ogs that have a mutation. Mutations are changes in the DNA
sequence as a result of bases being inserted, deleted, or changed. These changes can be
either beneficial to an organism or harmful, but the mutations can also be passed on from
one generation to the next in a population. Radiation from the sun or a man-made source
can cause mutations. The jumping frog population has not moved away from the nuclear
power plant, and some mutations in skin color have resulted.

Purpose: To examine whether or not mutations can help a species become more or less fit
in a particular environment.

Materials:
- 5 x 5 Sheets of paper (small frogs)
- Dice
- Origami handout
- Meter stick
- Ruler
- Post-it Notes
- Colored Pencils

Scenario: After ten years of living near the nuclear power plant, the jumping frog DNA
has mutated! The mutation affects the gene for skin color. Before the nuclear power
plant, most frogs were found in a 50:50 ratio of green to brown. However, scientists
monitoring the effects of the nuclear power plant have found red and albino frogs in the
population, and they also observed that the large frogs have been eliminated fiom the
population completely. To assist the scientists, your job is to follow the mutated frogs
through several generations to determine if the red and albino mutations have a positive
or negative impact on the frog population. Since the fi'ogs refuse to leave their habitat,
they still have to jump across a barrier in search of food and there are still the same
predators they have to avoid.

Hypothesis: Predict what color frog you think will have an advantage in the habitat, and

explain why you think it is the most fit. Predict what color frog you think will be at a
disadvantage and explain why you think it is the least fit.

108

Procedure:

1.

2.

Since the large frogs have been eliminated, you will only be working with small
frogs.

To determine the color of your fiog, you will roll a die. Use the table below to
determine what the genotype and phenotype of your frog will be based on the
number you rolled.

 

 

 

 

 

 

 

Number Rolled Phenotype Genotype
1 Green GG
2 Green GA
3 Brown BB
4 Brown BA
5 Red GB
6 Albino AA

 

 

 

 

 

Record the phenotype and genotype of your frog here:

On a small sticky note, write the genotype of your frog and color the sticky note
the appropriate color. A line of color would be enough.

Attach the sticky note on the back of one of the small frogs from yesterday.
Record the initial population of fi'ogs in the Generation 1 Table.

Lay the meter stick across your table and flip it on its side so that it is standing up
and no longer lying flat. The meter stick represents the barrier the fiog has to
jump over.

Measure 25 cm from the meter stick, and place a piece of masking tape here. This
will be the starting line that the frogs must jump fi'om.

Line your frog up at the starting line and push on the fiog’s “legs” to make it
jump. If your fiog makes it over the barrier, it survives the first obstacle. Frogs
that do not make it over the barrier starve to death and are no longer part of the
population.

 

 

 

 

 

 

 

 

 

 

10. Once on the other side of the barrier, the dreaded dice predators exist. Roll the
die. Use the number on the die and the chart below to determine if your frog
survives or not. The different colors of frogs have different chances of survival.

Color Survive if you roll: Death if you roll:
Green 1, 2, or 3 4, 5, or 6
Brown 1, 2, or 3 4, 5, or 6
Red 1, 2, 3, 4, or S 6
Albino 6 1, 2, 3, 4, or 5
11. Record the number of survivors in the Generation 1 Table.

12

. If your frog survived, you need to find a partner to reproduce with in your group.

Your frog can reproduce with any other frog because they are all the same
species.

109

13. Using the genotypes of the parents, draw a Punnett square for color.
Color:

 

 

 

 

 

 

14. Due to the nuclear power plant, the fi'ogs only produce one offspring per mating.
Tear off four pieces of paper and number them 1-4. Fold them in half and draw a
number. The numbers correspond to the genotypes in the Punnett squares. You
will have to draw two numbers, one for each of the traits.

l 2

 

 

3 4

 

 

 

 

15. Make your offspring, and record its phenotype in the Generation 1 Table, along
with all other offspring made in your group.

16. Starting with step 6 repeat the experiment using the parents that survived and the
offspring for three more generations, using steps 6-15.

Generation 1

 

 

 

 

 

 

Frog Phenotype Initial Number that Percent of Offspring Survivors
Population Survive Survival plus
Size Offspring_
Green
Brown
Red
Albino

 

 

 

 

 

 

 

Generation 2

 

 

 

 

 

 

Frog Phenotype Initial Number that Percent of Offspring Survivors
Population Survive Survival plus
Size OffsprinL
Green
Brown
Red
Albino

 

 

 

 

 

 

 

110

Generation 3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Frog Phenotype Initial Number that Percent of Offspring Survivors
Population Survive Survival plus
Size Offspring_
Green
Brown
Red
Albino
Generation 4
Frog Phenotype Initial Number that Percent of Offspring Survivors
Population Survive Survival plus
Size OffsprinL
Green
Brown
Red
Albino

 

 

 

 

 

 

 

 

10.

ll.

12.

13.

14.

15.

16.

Graph the initial population of fi'ogs for each generation. The generations should
go on the x-axis and the number of individuals should go on the y-axis. You need
to use four different colors to represent the different types of frogs. Everything
should fit on one piece of graph paper.

What color of frog proved to be the most fit? Why?

Which mutation showed a positive influence on survival? Why was this mutation

an advantage?

Which mutation had a negative impact on survival? Why was this mutation not
beneficial?

Are all mutations negative? Why or why not?

Explain what will happen to a frog if it has a negative mutation.

What color will most likely become the dominant color in future generations?
Give evidence to support your choice.

Is evolution occurring in this flog population? Why or why not?

111

Appendix [I Q: Salamander Speciation
Adapted from: Investigation 9.4 in Biological Science-An Ecological Approach
(BSCS Green Version), 1987, Kendall/Hunt Publishing Co.

Introduction: The small salarnanders of the genus Ensatina are strictly land-dwelling
animals. They even lay their eggs on land. Nevertheless, these salarnanders need a moist
environment and do not thrive in dry regions. In California, the species Ensatina
eschscholtzii has been studied by RC. Stebbins at the University of California
(Berkeley). There are several subspecies of this salamander found in different parts of
California. A subspecies is a geographically restricted population that is significantly
different from other populations of the same species. The way that scientists write out the
name of a subspecies is by adding another name after the species name.

Example: Genus Species Subspecies

Ensatina eschscholtzii croceator
To avoid writing out all of the names, scientists abbreviate the first two and only write
out the subspecies name (i.e. E. e. croceator).

Procedure:

1. You have gathered data about the habitats of each of the subspecies of E.
eschscholtzii. This information is found in Data Table 1.

2. Working in groups of two, you will map out the distribution of each of the
salamander subspecies on a map of California. Around each of the points, draw a
small circle that clearly defines where the salamander was found.

3. Each of the subspecies has a designated color you need to use on the map.

112

Data Table l- Salamander Subspecies Distributions

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Subspecies Number found Color on Map Locations on Map

E.e. croceator 15 Brown 32/R, 32/S, 30/T, 3l/T

E. e. eschscholtzii 219 Red 30/M, 32/O, 34/S, 35/V,
36/W, 35/Z, 38/Y, 40/Z,
36/Z, 4l/Z, 33/M, 34/W,
34/U

E.e. klauberi 71 Blue 36/Z, 38/a, 39/a, 40/a, 40/b,
40/Z, 36/a

E.e. oregonensis 373 Purple 9/B, 7/E, 6/E, 13/C, IO/C,
7/D, 15/D

E.e. picta 230 Yellow 2/B, 2/C, 3/C, 4/C

E.e. platensis 120 Green 8/J, 10/J, ll/M, 13/M,
lS/M, 15/O, 17/M, 15/P,
20/Q, 24/S, 21/R, 25/T,
26/U

E.e. xanthoptica 271 Orange 17/G, 17/F, 19/H, 19/0,
20/1, 20/J, 21/I

Unidentified 44 Pink 4/1, S/H, 7/H, 7/F, 6/J, 9/F

Population 8

Unidentified 13 Maroon 28/T, 27/T, 26/T, 28/S,

Population 9 29/T

Unidentified 131 Turquoise 23/J, 24/K, 24/1, 29/M,

Population 11 25/J, 25/1

No salarnanders Mark with an “x” 11/1, 14/1, l7/K, 22/N,

found in these “x” on the 26/Q, 5/M, 32/U, 32/a, 35/f

locations map

Questions:

1. Are the subspecies distributed evenly across the state? Use your knowledge of the
species habitat requirements to explain their distribution. What other factors
might affect their distribution?

113

. Compare your map to the actual pictures of the salamanders. What patterns do
you see? Where are the spotted salarnanders located? Where are the unspotted
salarnanders located? F orm a hypothesis about the distributions of the Spotted vs.
unspotted salarnanders.

. Subspecies E. e. eschscholtzii and E. e. klaauberi are different fiom each other.
Where are they found in relation to one another on the map?

. The unidentified populations are not new subspecies. If these salarnanders are not
separate subspecies, then what are they? Explain your answers.

. Since you don’t have a picture for unidentified population 11, draw what
individuals from this population could like. Explain why they would look this
way.

. Why is it unlikely that you would ever find individual salarnanders showing a
mixture of traits from E. e. picta and E. e. xanthopicta?

. You did not find any salamander hybrids between E. e. eschscholtzii and E. e.
klauberi, what does that tell you about their classification of subspecies? Keep in
mind the biological species concept.

. Imagine that you were looking for specimen j on the salamander sheet, where
would you expect to find it on the map? Draw a line on your map to Show where
you would expect to find other salarnanders like this one.

. Scientists think that the Ensatina salarnanders first lived in Oregon and then
spread to California. Explain how the many subspecies could have arisen from the
E. e. oregonensis population as it moved south through California.

114

Appendix II R: Seed Multiplication
Adapted from: Judith K. Wood
Woodrow Wilson Biology Institute

Introduction: Have you ever eaten a cucumber and wondered why there are so many
seeds inside? Every seed in the cucumber has the potential to become a cucumber plant.
The same is true of apple seeds, tomato seeds, and orange seeds. Why is it that the world
is not overrun with plants?

Purpose: To estimate the future plant population based on the number of seeds found in a
fruit or vegetable and compare predictions with the real world.

1.

Count and record the number of seeds in your fruit or vegetable, and record the
number.

If every seed germinated, how many plants would there be in the second

generation? Record this number.

If each of the plants in the second generation produces 10 new fruits or
vegetables, how many new fi'uits or vegetables would there be? Record this
number.

If each of the second generation plants produced 100 seeds, how many new plants
would be produced in the third generation?

How many plants would the original fi'uit have produced by the third generation?

Draw a graph of the generation number vs. the number of offspring for the first
three generations. The generation number goes on the x-axis and the number of
offspring goes on the y-axis.

Based on your graph and calculations, explain why plants have not yet taken over
the world.

Do all of the seeds germinate and all of the plants produce the expected number of
plants? Why or why not?

115

Charles Darwin made two observations:
A) The number of offspring produced exceeds the number of parents.
B) The number of parents remains constant fiom generation to generation.

9. How many parents were present in the first generation?

10. Based on Darwin’s observations, how many parents would be present in the
second generation? Does this agree with your calculations? Does this agree with
what you see in nature?

1 1. Assuming Darwin’s observations are more correct in nature than your
calculations, what are some possible reasons for the difference?

12. Using Darwin’s two observations, what conclusions can you draw about why
more offspring are produced than will survive?

116

APPENDIX III

Assessments and Rubrics

117

Appendix III A: Evolution Unit Pre—Survey and Post-Survey

Answer the following questions on a scale of 1-5.

1-
2-
3-
4-
5-

1.

10.

11.

12.

13.

14.

15.

Strongly Disagree
Disagree
Neutral/No opinion
Agree

Strongly Agree

Variation exists within members of a population.

1 2 3 4 5

Artificial selection has been used by humans for thousands of years.
1 2 3 4 5

DNA mutations are always harmful.

l 2 3 4 5

Organisms are linked by a universal genetic code.

1 2 3 4 5

Most species on earth were created at the same time.

1 2 3 4 5

The earth is 6,000-10,000 years old.

1 2 3 4 5

The fossil record is incomplete, and thus provides poor evidence for the history of
life on earth.

1 2 3 4 5

New species discovered today have been on earth for thousands of years.
1 2 3 4 5

Humans as a population are perfectly adapted.

l 2 3 4 5

The fitness of an organism is the ability of an organism to survive and reproduce.
1 2 3 4 5

A theory is just a guess with little or no evidence to support it.

1 2 3 4 5

There is no evidence for evolution.

1 2 3 4 5

Evolution is not occurring in organisms today.

I 2 3 4 5

Evolution states that humans came from monkeys.

l 2 3 4 5

It is most likely that humans originated from Afiica.

1 2 3 4 5

118

Open response questions
1. What is science?

2. What is science based on?

3. Explain why evolution is considered a theory.

4. Do labs and activities enhance your learning? Explain why or why not.

5. What is your opinion of evolution?

6. Do you think that evolution should be taught in schools? Why or why not?

7. How do you think life on earth originated? Explain your answer.

119

Appendix III B: Rubric for Evolution Unit Pre-Survey and Post-Survey

Answer the following questions on a scale of 1—5.
1- Strongly Disagree

2- Disagree
3- Neutral/No opinion
4- Agree

5- Strongly Agree

MThe following fifteen questions were meant to provide insight on the opinions and
misconceptions of the students concerning the statements on evolution below. No rubric
was required to gather this data.

1. Variation exists within members of a population.
1 2 3 4 S
2. Artificial selection has been used by humans for thousands of years.
1 2 3 4 5
3. DNA mutations are always harmful.
1 2 3 4 S
4. Organisms are linked by a ruriversal genetic code.
1 2 3 4 5
5. Most species on earth were created at the same time.
1 2 3 4 5
6. The earth is 6,000-10,000 years old.
1 2 3 4 5
7. The fossil record is incomplete, and thus provides poor evidence for the history of
life on earth.
1 2 3 4 5
8. New species discovered today have been on earth for thousands of years.
1 2 3 4 5
9. Humans as a population are perfectly adapted.
1 2 3 4 5
10. The fitness of an organism is the ability of an organism to survive and reproduce.
1 2 3 4 5
11. A theory is just a guess with little or no evidence to support it.
1 2 3 4 5
12. There is no evidence for evolution.
1 2 3 4 5
13. Evolution is not occurring in organisms today.
1 2 3 4 S
14. Evolution states that humans came from monkeys.
l 2 3 4 5
15. It is most likely that humans originated from Afiica.
1 2 3 4 5

120

Open response questions
** Questions 1-3 were scored based on a three-point rubric.
1. What is science?
3 points- Science is an organized way of using evidence to learn about the natural
world.
2 points- Science is the study of the natural world.
1 point- Science is the study of everything.

2. What is science based on?
3 points- Science is based on evidence, facts, theories, and proof.
2 points- Two of the answers listed above.
1 point- One of the answers for three points.

3. Explain why evolution is considered a theory.
3 points- Evolution is considered a theory because there is evidence to support it.
2 points- Evolution is a theory because it explains something.
1 point- Evolution is a theory because it is the best explanation scientists have.

”The following questions were subjective, with no right or wrong answers. Students
were divided into groups based on their responses.
4. Do labs and activities enhance your learning? Explain why or why not.

Group A- Yes because. . ..

Group B— No because. . ..

5. What is your opinion of evolution?
Group A- It is real or possible
Group B- It is not true
Group C- No opinion or I don’t know

6. Do you think that evolution should be taught in schools? Why or why not?
Group A- Yes because...
Group B- No because...

7. How do you think life on earth originated? Explain your answer.
Group A- From other organisms, like bacteria.
Group B- God created life
Group C- The Big Bang
Group D- No opinion or I don’t know

121

Appendix III C: Evolution Pre-Test and Post-Test

Answer each of the following to the best of your ability.

. What is natural variation in a population?
. Give at least two examples of variations that exist within a population of

organisms.

. What are the two main sources of genetic variation within a population? Explain
how each of the sources increases variation.

. Why are mutations in the gametes able to be passed from one generation to the
next in organisms that sexually reproduce?

. What is an adaptation?

. Give an example of a human adaptation and explain why the adaptation is useful.

Explain the role of artificial selection in agriculture.

. Compare the differences and similarities between artificial selection and natural
selection.

. Describe the role of the environment in natural selection. Think about things like
natural disasters, predator-prey relationships, and competition.

10. How does natural selection increase the fitness of a population?

122

11. What is a scientific theory?

12. What is necessary for an idea to become a theory?

13. What does the theory of evolution state?

14. Provide at least three pieces of evidence for evolution.

15. How can geographic isolation result in speciation?

123

Appendix 111 D: Evolution Pre-Test and Post-Test Assessment Rubric
Answer each of the following to the best of your ability.

** The following questions were graded based on a three-point rubric.

1. What is natural variation in a population?
3 points- Natural variation is the differences that exist among organisms of a
population.
2 points- The differences between individuals
1 point- Differences

2. Give at least two examples of variations that exist within a population Of
organisms.

3 points- Two examples of variation

2 points- One example of a variation

1 point- Variations are differences

3. What are the two main sources of genetic variation within a population? Explain
how each of the sources increases variation.

3 points- Both sources with explanations

2 points- One source with explanation

I point- One or two sources without explanation

4. Why are mutations in the gametes able to be passed from one generation to the
next in organisms that sexually reproduce?
3 points- Mutations in body cells cannot be passed on, only those that occur in the
gametes.
2 points- Garnetes form offspring.
1 point- Garnetes are the sperm and egg

5. What is an adaptation?
3 points- An inherited characteristic that increases an organism’s chance of
survival
2 points- Something that helps an organism survive
I point- An example of an adaptation

10. Give an example of a human adaptation and explain why the adaptation is usefirl.
3 points- Example with explanation
2 points- Example with an incorrect explanation
I point- Example only

11. Explain the role of artificial selection in agriculture.
3 points- Definition of artificial selection and what it is used for
2 points- Definition only
1 point- An example like selective breeding

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12.

13.

14.

15.

16.

17.

18.

19.

Compare the differences and similarities between artificial selection and natural
selection.

3 points- Differences and similarities

2 points- Either the differences or the similarities

1 point- Definition of one of the processes

Describe the role of the environment in natural selection. Think about things like
natural disasters, predator-prey relationships, and competition.

3 points- The environment places pressures on a species to survive and organisms
that are better adapted will survive to reproduce.

2 points- Natural disasters kill weaker individuals

1 point- Organisms have adaptations to help them survive natural disasters

How does natural selection increase the fitness of a population?

3 points- Natural selection increases the genes and traits that provide an advantage
for the survival of a population by eliminating weaker individuals.

2 points- The stronger, better organisms survive to reproduce

1 point- Survival of the fittest

What is a scientific theory?

3 points- A well-tested explanation that unifies a broad range of observations
2 points- A well-tested explanation

I point- An explanation for something

What is necessary for an idea to become a theory?
3 points- Evidence, proof, experiments, data, facts
2 points- One of the above answers

1 point- A hypothesis

What does the theory of evolution state?
3 points- Organisms change over time

2 points- Things change

lpoint- Evidence for evolution

Provide at least three pieces of evidence for evolution.

3 points- Three examples given: fossil record, DNA, homologous structures,
embryonic development

2 points- Two examples given

1 point- One example given

How can geographic isolation result in speciation?

3 points- Two populations are separated physically by geographic barriers that
may or may not result in changes in a population that lead to speciation.

2 points- Two populations change because of a physical barrier

1 point- Two populations are separated by a physical barrier

125

Appendix III E: Evolution Multiple Choice Test
Evolution Test

1. Who was the first scientist to recognize that organisms change over time?
A) Darwin B) Mendel C) Lamarck D) Whitfield

2. True or False: Acquired characteristics, like having your appendix removed, can be
passed on from one generation to the next.

3. What is a well-supported, testable explanation of things that occur in the natural
world?

A) theory B) hypothesis C) experimental D) scientific

4. The theory of evolution states:
A) humans evolved from apes B) acquired characteristics are inheritable
C) organisms change over time D) none of the above

5. Which of the following is an example of natural variation?
A) fiuit production B) milk production
C) height in humans D) all of the above

6. True or False: The struggle for existence states that organisms compete with each other
for limited resources.

7. What is the ability of an individual to survive and reproduce called?
A) adaptation B) fitness C) survival D) natural selection

8. True or False: Adaptations can not be inherited.

9. Individuals that are more successfirl are likely to survive to reproduce.
A) more B) less

 

10. Which of the following principles states that species today look different than their
ancestors?

A) struggle for existence B) principle of common descent

C) descent with modification D) natural selection

11. True or False: The principles of descent with modification and common descent
imply there is a single tree of life.

12. Which of the following give evidence for evolution?

A) fossil record B) homologous structures C) embryonic development
D) all of the above

126

13. In vertebrates, the bones of the limbs all develop fi'om the same embryonic tissues,
what is this an example of?

A) vestigial organs B) homologous chromosomes

C) homologous structures D) none of the above

14. In humans, the appendix no longer serves a purpose, but we still have one, what is
this an example of?

A) vestigial organs B) homologous chromosomes

C) homologous structures D) none of the above

15. True or False: Natural selection works only on inherited traits.

16. What is the combined genetic information of all members of a population called?
A) relative frequency B) fitness C) gene pool D) alleles

17. Which of the following is not a cause of genetic variation?
A) mutations B) crossing over C) gene shuffling D) mitosis

18. True or False: Mutations are always bad.

19. How many phenotypes are possible with a single gene trait?
A) I B) 2 C) many

20. True or False: Single gene traits show more variation than polygenic traits.

21. What does the graph of a polygenic trait look like?
A) line graph B) bar graph C) exponential curve D) bell curve

22. What does natural selection work on?
A) genes B) phenotypes C) genotypes D) individuals

23. True or False: Evolution works on individuals and not on populations.
24. What type of selection causes an increase in the average phenotype and causes the
ends to pinch in on the bell curve?

A) directional B) stabilizing C) disruptive D) none of the above

25. What type of selection does the graph below represent?
A) directional B) stabilizing C) disruptive D) none of the above

26. What type of selection can result in two distinct phenotypes?
A) directional B) stabilizing C) disruptive D) none of the above

27. A random change in allele frequency in a small population is called:
A) gene shuffling B) genetic drift C) mutations D) founder effect

127

28. When gene frequencies remain constant, what is this called?
A) genetic drift B) gene shuffling C) genetic equilibrium D) mutation

29. True or False: If allele fi'equencies stay the same, evolution does not occur.

30. Which of the following is not required to maintain genetic equilibrium?
A) large population B) no migration C) mutations D) random mating

31. True or False: Large populations increase the influence of genetic drift.

32. The formation of a new species is called:
A) reproductive isolation B) genetic drift C) founder effect D) speciation

33. When two populations do not interbreed because of courtship rituals, this is:
A) behavioral isolation B) reproductive isolation C) geographic isolation
D) temporal isolation

34. True or False: Geographic isolation always results in the formation of a new species.
35. When two populations reproduce at different times, this is an example of what type of

isolation?
A) behavioral B) reproductive C) geographic D) temporal

Matching

36. Combined genetic information of all A) adaptation
members of a particular population.

37. Differences among individuals of a B) gene pool
species

38. Inherited characteristic that increases an C) natural variation
organism’s chance of survival.

39. Well-tested explanation D) speciation

40. Formation of a new species

128

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129

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