Ch 14 Study Guide:
Evolution: How Change Occurs
Section 14-1: Developing a Theory of Evolution
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In this section you learned that evolutionary theory is a collection of carefully reasoned
about how evolutionary change occurs. The fact that plants and animals have changed over time has been
obvious to scientists for many years. How and why this change occurs is not so obvious.
Jean
proposed one of the first explanations for evolutionary change. However, his
theory was based on three assumptions that we now know to be incorrect: (1) Organisms have an inborn urge
to
themselves, (2) organs can change in size and shape in response to the
of
the organisms, and (3) acquired traits can be passed from parents to
.
Charles Darwin’s explanation for evolutionary change was influenced by the ideas of many other people. After
reading Charles
book, Darwin became convinced that the Earth had existed for a
time – long enough for
to occur. The work of plant and animal breeders demonstrated
that crops and livestock changed over time as a result of
. This
indicated to Darwin that organisms could – and did- evolve as the result of
occurring
selective forces. The ideas of Thomas
also had a powerful influence on Darwin. In writing
about human
and society, Malthus noted that the animal and plant populations are, like the
human population,
to a certain size. Darwin recognized that the forces that
the growth of populations were also the forces behind evolutionary change.
Thinking It Through: Building Vocabulary Skills
Recall that the scientific usage of the term theory is different from the common usage. In common usage, a
theory may be an idea or a hunch that is not backed up by strong evidence. In scientific usage, a theory is a
verified, time-tested concept that logically explains past events and makes useful an dependable predictions
about the natural world.
Read each of the following statements about evolutionary theory carefully. In the space provided, indicate
whether each statement is true or false.
1. Evolutionary change is indefinable.
2. Evolutionary theory is based on vague hunches.
3. Current evolutionary theory is exactly like Darwin’s theory.
4. Much research in many branches of biology is based on evolutionary theory.
5. Because some of Darwin’s original theory was not entirely correct, it is possible that evolution does not
occur.
6. Evolutionary theory is a collection of carefully reasoned hypotheses about how the evolutionary changes
occurs.
7. Evolutionary theory is the foundation on which the rest of biological science is built.
8. Darwin was the first person to come up with an explanation for evolution.
Ch 14 Study Guide:
Evolution: How Change Occurs
Influences on Darwin: Examining the Main Ideas
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1. People who read Darwin’s book On the Origin of Species by Means of Natural Selection are often surprised
that many pages at the beginning of the book discuss the breeding of pigeons. In these pages, Darwin also
described the many varieties of domesticated pigeons. Why do you think Darwin chose to spend so much time
discussing pigeons?
2. The following passage is from the first chapter of An Essay on the Principle of Population as It Affects the
Future Improvement of Society, by Thomas Malthus.
“Through the animal and vegetable kingdoms, nature has scattered the seeds of life abroad with the most
profuse and liberal hand. She has been comparatively sparing in the room, and the nourishment necessary to
rear them. The germs of existence contained in this spot of earth, with ample food, and ample room to expand
it, would fill millions of worlds in the course of a few thousand years. Necessity, that imperious, all-pervading
law of nature, restrains them within the prescribed bounds. The race of plants, and the race of animals shrink
under this great restrictive law. And the race of man cannot, by any efforts of reason, escape from it. Among
plants and animals its effects are waste of seed, sickness, and premature death…”
a. What are the main ideas in this passage?
b. In your own words, define the “great restrictive law” mentioned in the passage.
c. According to this passage, how does nature keep the growth of a plant or an animal population under
control.
d. How might the forces that control the size of populations relate to selection?
Concept Mapping.
Consider the concepts presented in Section 14-1 and how you would organize them into a concept map. Now
look at the concept map for Chapter 14 at the end of this package. Notice that the concept map has been started
for you. Add the key facts and concepts you fell are important for Section 14-1. When you have finished the
chapter, you will have a completed concept map.
Ch 14 Study Guide:
Evolution: How Change Occurs
Section 14-2: Evolution by Natural Selection
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In this section you were introduced to the concept of
. Darwin proposed
that natural selection operates in a fashion similar to the process of
selection used by
farmers. Darwin observed that plants and animals showed variations, and he realized that many of them were
. He also observed that high birthrates and a shortage of life’s necessities forced organisms to
constantly struggle in order to exist. Darwin concluded that those organisms that possessed characteristics that
made them well-suited for their environment
; those less well equipped did not
Darwin called this principle
. In this section you also read about an
interesting example of natural selection in action. Recall that peppered moths come in two forms: a
colored form and a
colored form. The form that
in with the tree bark in a
given area is more common than the nonform. An experiment by H.B.D. Kettlewell
demonstrated that the
moth form has a higher survival rate.
Writing Definitions: Building Vocabulary Skills
In your words, define each of the following terms.
1. Natural Selection:
2. Survival of the Fittest:
3. H.B.D. Kettlewell:
Concept Mapping:
Consider the concepts presented in Section 14-2 and how you would organize them into a concept map. Now
look at the concept map for Chapter 14 at the end of this package. Notice that the concept map has been started
for you. Add the key facts and concepts you fell are important for Section 14-2. When you have finished the
chapter, you will have a completed concept map.
Section 14-3: Genetics and Evolutionary Theory
Darwin worked under a serious handicap when he was developing his theory of evolution: He did not know
how
traits are passed from parents to
. And as you learned in this
section,
and evolutionary theory are inseparable.
In this section you discovered how evolutionary theory is defined in genetic terms. You also became familiar
with the terms that link genetics and evolution. For example,
are the source of the variation
upon which natural selection operates, and the group of genes possessed by a population is known as its
. In addition, you learned new definitions for familiar terms. Evolution can be defined as
. Species can be defined as a group of
similar-looking organisms that
with one another and produce
offspring
in the natural environment.
Ch 14 Study Guide:
Evolution: How Change Occurs
Matching Definitions: Building Vocabulary Skills
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In the space provided, write the term that best fits each of the following descriptions.
1. All the behaviour and physical characteristics produced by the interaction of
genotype and environment.
2. Any change in the relative frequencies of alleles in a gene pool
3. The success of an organism in passing on its genes
4. A collection of individuals of the same species in a given area whose members can
breed with one another.
5. A graph of this often forms a bell-shaped curve.
6. The number of times an allele occurs in a gene pool compared with the number of
times other alleles for the same gene occur.
7. Any genetically controlled characteristic of an organism that increases its fitness
8. Once defined as a group of organisms that look alike.
Concept Mapping
Consider the concepts presented in Section 14-3 and how you would organize them into a concept map. Now
look at the concept map for Chapter 14 at the end of this package. Notice that the concept map has been started
for you. Add the key facts and concepts you fell are important for Section 14-3. When you have finished the
chapter, you will have a completed concept map.
Section 14-4: The development of New species
In the first part of this section you were introduced to the concept of the niche. A species niche is the
combination of its
in the environment and the place in which it lives. If two species
occupy two different niches, they can
. If their niches are the same or extremely similar, they
will
with each other for
and living
. If one species is
much better at making a living than the other, it may cause its competitor to become
. No two
species can occupy the same niche in the same location for a long period of time.
You then learned about speciation, the process in which new species evolve from old species, by reading about
Darwin’s
. Recall that the fourteen species of Darwin’s finches evolved from a
ancestral species. In the past, populations of the ancestral finches became
from other
populations. The
populations
to local conditions. In time, the
gene pools of the finch populations had changed so much that the finch populations could not
.
Finally, you learned about some basic patterns of evolution. Adaptive radiation, or
evolution, is the process in which an ancestral species gives rise to a diversity of new species. (like Darwin’s
).
evolution is the process in which species from different
evolutionary lines grow to
one another because they adapt to similar
.
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Ch 14 Study Guide:
Evolution: How Change Occurs
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Defining Terms: Building Vocabulary Skills.
In your own word, define each of the following terms.
1. Divergent evolution:
2. Analogous Structures:
3. Niche:
4. Reproductive Isolation:
5. Adaptive Radiation:
6. Speciation:
7. Convergent Evolution:
Analyzing Diagrams: Using the Main Ideas
Some of the animals shown in the accompanying diagrams lived long ago. Others are still alive today.
Examine diagrams A and B. then answer the following questions.
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Ch 14 Study Guide:
Evolution: How Change Occurs
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1. What process is shown in diagram A? Explain.
2. Why do the animals in diagram A look different from one another?
3. What process is shown in diagram B? Explain.
4. Why do the animals in diagram B look similar to one another?
Concept Mapping
Consider the concepts presented in Section 14-4 and how you would organize them into a concept map. Now
look at the concept map for Chapter 14 at the end of this package. Notice that the concept map has been started
for you. Add the key facts and concepts you fell are important for Section 14-4. When you have finished the
chapter, you will have a completed concept map.
Ch 14 Study Guide:
Evolution: How Change Occurs
Section 14-5: Evolutionary Theory Evolves
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Evolutionary theory has been modified over the years as scientists formulate theories about the details of
evolutionary change. In this section you learned about some of the major modifications to Darwin’s original
theory of evolution by natural selection.
Sometimes the relative
of an allele in a gene pool changes merely by
. In
other words, evolution may occur in the absence of natural selection. This is known as
.
Darwin envisioned evolution as being a slow,
and continuous process. However, this is not
always the case. In a few cases, evolution may occur so slowly that gene pools remain the same for long
periods of time. Alternatively, evolution may occur relatively
. This theory is called
.
Defining Terms: Building Vocabulary Skills
In your own words, define each of the following terms.
1. Punctuated Equilibria:
2. Genetic Drift:
3. Gradualism:
4. Mass extinction:
5. Equilibrium:
Understanding concepts: Using the Main Ideas:
1. Under what circumstances might genetic drift occur?
2. What does genetic drift imply about an organism’s characteristics and its fitness?
3. How might the theory of punctuated equilibria explain “missing links” in the fossil record?
4. Under what circumstances might rapid evolution occur?
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Ch 14 Study Guide:
Evolution: How Change Occurs
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Concept Mapping
Consider the concepts presented in Section 14-5 and how you would organize them into a concept map. Now
look at the concept map for Chapter 14 at the end of this package. Notice that the concept map has been started
for you. Add the key facts and concepts you fell are important for Section 14-5. When you have finished the
chapter, you will have a completed concept map.