Name
Period
Test #2-Evolution Review
Exercise 1 – Evidence for evolution
In addition to fossils, examples of natural selection, and examples of artificial selection, there are other kinds
of evidence for evolution: Biogeography, comparative anatomy, and molecular biology. Each of the
examples below illustrates which of these kinds of evidence?
1. Fertilized eggs of earthworms, insects, and snails go through the same
pattern of cell division.
2. The same gene seems to be involved in the formation of eyes in many
animals.
3. The genes of humans and chimpanzees are about 96% identical.
4. Remains of upright-walking but small-brained apes have been found in
Africa.
5. All animals with backbones have 12 pairs of nerves extending from the
brain.
6. Bacteria quickly become resistant to antibiotics.
7. The American Kennel Club recognizes more than 150 dog breeds.
8. Many unique marsupial mammals live in Australia.
9. A protein called albumin is very similar in dogs and wolves, less
similar in dogs and cats.
10. The farther an island is from the mainland, the more unique its plants
and animals.
11. The limbs of all land vertebrates have an upper “leg” bone and two
lower “leg” bones.
12. Humans have small tailbones, and occasionally a baby is born with a
short tail.
13. Animals called trilobites were common in the oceans 300 million
years ago, but they have been extinct for millions of years.
14. In all living things, AUG is the mRNA “start” codon.
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15. Some whales possess vestigial hind leg and foot bones.
16. Cabbage, cauliflower, and broccoli were all bred from a wild mustard.
Exercise 2 – Evidence for evolution Homologues structures
A human arm and a bat wing are homologous structures  features that may have different functions but are
structurally similar because of common ancestry. Such homologies, whether anatomical or molecular, are
important clues to evolutionary relationships. Circle the number of the examples above that illustrate
homologous structures.
Exercise 3 – Evolution in action
Circle the word that best matches each statement.
1. A group of individuals of the same species: gene pool, population
2. What natural selection acts on: individual, population
3. What actually evolves: individual, population
4. All the alleles in all the individuals in the population: genome, gene pool
5. Change in relative frequencies of alleles in the gene pool: microevolution, macroevolution
6. Causes of variation (circle all that apply): mutation, natural selection, sexual reproduction
7. Portion of variation relevant to natural selection: acquired, genetic
8. Produces new alleles: mutation, sexual reproduction
9. Mutations that affect a population’s variability: Somatic mutations, mutations in gametes
10. Generates most new gene combinations in animals and plants: mutations, sexual reproduction
11. Sexual processes that generate variation (circle all that apply): crossing over, independent assortment,
random fertilization
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Exercise 4 – Hardy-Weinberg Equilibrium
Microevolution is the change of frequencies of alleles in the gene pool. To see what happens when
microevolution occurs, it is helpful to first look at a hypothetical population that is not evolving  a population
at “Hardy-Weinberg equilibrium”. Imagine a population of 100 annual wildflowers, some red and some yellow.
The red allele, R, is dominant; the yellow allele, r, is recessive. There are 36 RR plants in the population, 48 Rr
plants, and 16 rr (yellow) plants. If the population is at Hardy-Weinberg equilibrium, what will be the
frequencies of the various genotypes and the frequencies of the two alleles, R and r, in the next generation?
First figure out the genotype frequencies for the current generation:
A. Phenotypes
Red
Red
Yellow
B. Genotypes
C. Number of plants (total 100)
D. Genotype frequencies
(number of genotypes/100)
Next, figure out the frequencies of R and r alleles in the gene pool:
E. Number of R alleles in the gene pool
F. Number of r alleles in the gene pool
G. Allele frequencies
(number of R alleles/200
or number of r alleles/200)
Now, what will be the frequencies of the various genotypes and the frequencies of the two alleles, R and r, in
the next generation?
What would you predict for the third generation? Why?
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Exercise 5 – More Hardy-Weinberg Equilibrium
1. Allele B for white wool, is dominant over allele b, for black wool. In a sample of 900 sheep, 891 are white
and 9 are black. Estimate the allelic and genotypic frequencies in this sample, assuming the population is in
equilibrium.
2. In a population that is in Hardy-Weinberg equilibrium, the frequency of the recessive homozygous genotype
of a certain trait is 0.09. What is the percentage of individuals homozygous for the dominant allele?
3. In a population that is in Hardy-Weinberg equilibrium, 36% of the individuals are recessive homozygotes for
a certain trait. For the same trait, what is the percentage in this population of homozygous dominant
individuals? Of heterozygous individuals?
4. In corn, yellow kernel color is governed by a dominant allele; white, by its recessive allele. A random
sample of 1,000 kernels from a population that is in equilibrium reveals that 910 are yellow and 90 are white.
What are frequencies of the yellow and white alleles in this population? What is the percentage of
heterozygous in this population?
5. A rare disease due to a recessive allele, which is lethal when homozygous, occurs with a one in a million.
How many individuals in a town of 14,000 can be expected to carry this allele?
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Exercise 6 – Multiple choice
1. Breeding of plants and animals by humans is called
a.
b.
c.
d.
e.
natural selection
balancing selection
founder effect
artificial selection
intersexual selection
2. In evolutionary terms, an organism’s fitness is measured by its
a.
b.
c.
d.
e.
health
contribution to the gene pool of the next generation
mutation rate
genetic variability
stability in the face of environmental change
3. Organisms that possess homologous structures probably
a.
b.
c.
d.
e.
are headed for extinction
evolved form the same ancestor
have increased genetic diversity
by chance has similar mutations in the past
are not related
4. Darwin
a.
b.
c.
d.
e.
was the first person to conceive that organisms could change over time
believed that organisms could pass on acquired changes to offspring
was the first biologist to win the Nobel Prize
worked out the mechanism of evolution  natural selection
was the first to realize that fossils are remains of ancient organisms
5. In a population of black bears, which would be considered the fittest?
a.
b.
c.
d.
e.
the biggest bear
the bear having the most mutations
the healthiest bear
the strongest, fiercest bear
the bear that leaves the most descendants
6. Which of the following would result in evolutionary adaptation of a mouse population to its environment?
a.
b.
c.
d.
e.
half the mice are killed by an avalanche
a mutation for spotted fur
several mice leave the area and mate with individuals elsewhere
mice with thicker fur best survive a cold winter
mice are most likely to mate with close neighbors
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7. Each of us is part of the ongoing evolution of the human species. Which of the following occurrences would
have the greatest impact on the future biological evolution of the human population?
a.
b.
c.
d.
e.
You work out everyday so that you stay physically fit and healthy
a mutation occurs in one of your skin cells
you move to Hawaii, the state with the longest life expectancy
a mutation occurs in one of your sperm or egg cells
you encourage your children to develop their intellectual abilities
8. Fossils are formed
a. from animals but not plants.
b. Primarily from the soft tissue an organism
c. most often in sedimentary rock.
d. in ways that reveal the structure but not the
behavior of an organism.
9. When hard minerals fill an imprint of an organism, they eventually form a model of the organism called a
a. cast
b. mold
c. tissue
d. stratum
10. According to the law of superposition, the lowest layer in a cross section of rock
a. is the most recent.
b. is the oldest.
c. has the fewest fossils.
d. contains only the fossils of burrowing
animals.
11. The fossil record indicates that the first organisms to appear on Earth were
a. marine invertebrates.
b. land plants.
c. reptiles.
d. prokaryotes.
12. A comparison of recently formed fossil types with types of living organisms shows that
a.
b.
c.
d.
new organisms arise in areas where similar forms already live.
modern organisms are very different from extinct forms that inhabit the same area.
organisms that become extinct do not resemble modern organisms.
a new organism cannot arise in an area until a similar form has already become extinct.
13. If Lamarck’s hypothesis of species modification were true, the children of a person who developed
large muscles by lifting weights would be born with
a.
b.
c.
d.
smaller-than-average muscles.
normal-sized muscles.
normal-sized muscles that would become larger only if the children also lifted weights
larger-than-average muscles.
14. When Darwin saw fossil shells of marine organisms in the mountains, he reasoned that
a.
b.
c.
d.
powerful storms scooped the animals out of the ocean and left them in the mountains.
ancient rock beds that were beneath the sea were elevated to form mountain ranges.
the ancient oceans were so deep that they covered the mountains.
the organisms that left the fossils migrated from the ocean to the mountains.
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15. Darwin’s theory of descent with modifications states that
a.
b.
c.
d.
newer forms appearing in the fossil record are the modified descendants of older species.
organisms that descend from high elevations are modified as they acquire new traits.
all living things descend from a recent common ancestor on the Galápagos Islands.
individuals modify their behavior to survive and then pass those modifications on to
their descendants.
16. According to Darwin’s theory of modification by natural selection,
a.
b.
c.
d.
individuals are modified by adverse environmental conditions.
the environment affects all organisms in a population in the same way.
populations of all organisms grow unchecked under natural conditions.
organisms that have more favorable traits tend to leave more offspring.
17. Natural selection is sometimes described as “survival of the fittest.” Which of the following best measures
an organism’s fitness?
a.
b.
c.
d.
e.
how many fertile offspring it produces
its mutation rate
how strong it is when pitted against others of its species
its ability to withstand environmental extremes
how much food it is able to make or obtain
18. The wing of a bat and the foreleg of an alligator are
a. analogous features
b. homologous features
c. vestigial features
d. artificially selected features
19. Features that were useful to an ancestral organism but are not useful to a modern organism
that has them are said to be
a. analogous
b. homologous
c. vestigial
d. artificially selected
20. Embryological comparisons reveal that
a.
b.
c.
d.
all vertebrate embryos look similar at early stages of development.
embryos of different vertebrates look more similar as development proceeds.
rabbit embryos look like adult fish.
gorillas begin life as fish and then develop into gorillas during an embryonic stage.
Exercise 7 – Essay Questions
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1. Jason and Lindsay collected some wildflower seeds form a meadow and scattered them along the roadside
near their home. As the weather got hotter, some of the seedlings began to wither. Jason said, “Hey, those
scrawny plants are going to have to adapt or they are going to die.” Lindsay replied, “They may not adapt,
but the wildflower population might.” What did she mean?
2. A population of 100 fish in an aquarium consists of 49 homozygous green individuals, 42 heterozygous
green individuals, and 9 white individuals. What are the frequencies of the three genotypes in the
population? What are the frequencies of the green and white alleles in the gene pool? If the population is at
Hardy-Weinberg equilibrium, what will be the genotype and allele frequencies in the next generation of fish?
3. Describe 5 ways in which the fish population in Question 2 could be caused to deviate from Hardy-Weinberg
equilibrium.
4. An ecologist studying predators and their prey in White Sand Dunes State Park found that nocturnal pocket
mice exist in dark and light morphs. In the area, 42% of the mice are dark and 58% are light. Because owls
swallow their prey whole and cough up “pellets” consisting of bones and fur, the ecologist was able to
discover that 61% of the mice caught by owls were dark, and 39% were light. What is likely to happen to the
pocket mouse population in the future, and why?
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