Chapter 6

Question 1

__________ and its biota were a source of inspiration to Charles Darwin as he formulated his
theory of evolution by natural selection. This place also remains a mecca for biologists like Peter
and Rosemary Grant who are interested in the study of evolutionary biology.
A) Antarctica D) The Galápagos Islands
B) Australia E) The California Channel Islands
C) The Orkney Islands

Answer 1

D) The Galápagos Islands

Question 2

Why did average beak size increase in surviving individuals of Darwin’s medium ground finch
(and their progeny) during a period of severe drought in the Galápagos?
A) Individuals eating the harder seeds available during the drought developed larger beaks and
passed this trait on to their offspring.
B) Individuals with larger beaks could eat the harder seeds available during the drought and
survived better than individuals with smaller beaks.
C) Individuals with larger beaks are always at an advantage.
D) The observed change in beak size was purely the result of chance.

Answer 2

B) Individuals with larger beaks could eat the harder seeds available during the drought and
survived better than individuals with smaller beaks.

Question 3

The only mutations of interest to evolutionary biologists are those that cause changes in the
structure of protein products.
A) True B) False

Answer 3

B) False

Question 4

A new protein produced by a mutant gene may or may not have properties different from those
of the original protein. If its properties are altered, these properties are most likely to be
__________ to the individual.
A) beneficial B) harmful C) neutral

Answer 4

B) harmful

Question 5

Mutation is a random force in evolution that produces genetic variation independently of the
fitness consequences of the genetic change for the individual that bears the mutation.
A) True B) False

Answer 5

A) True

Question 6

The development of resistance to cyanide poisoning in California citrus scale is an excellent
example of evolution by natural selection. Which of the following characteristics of this
situation were critical to the evolutionary process?
A) There was variation in cyanide resistance among individuals.
B) There was inheritance of cyanide resistance.
C) There were differences in fitness related to variation in cyanide resistance.
D) All of the above were critical to the evolutionary process.

Answer 6

D) All of the above were critical to the evolutionary process.

Question 7

Natural selection is an external force that urges organisms toward some predetermined goal.
A) True B) False

Answer 7

B) False

Question 8

Which of the following is relevant to the evolutionary process?
A) how fast rabbits can run
B) whether running speed affects the ability of rabbits to leave successful offspring
C) both A and B
D) neither A nor B

Answer 8

B) whether running speed affects the ability of rabbits to leave successful offspring

Question 9

The process that creates natural selection is ecological—the interaction of individuals with their
environments, including physical conditions, food resources, predators, other individuals of the
same species, and so on.
A) True B) False

Answer 9

A) True

Question 10

When the field cricket, Teleogryllus oceanicus, experienced strong selective pressure from a
predator that used sound to locate singing males, the frequency of males capable of producing
mating calls decreased in the population. Although this adaptive response was beneficial, it also
had a negative consequence. What was this negative consequence?
A) Silent males are unable to attract mates.
B) Silent males are also deaf.
C) Silent males have defective wings and are unable to fly.
D) Silent males are unable to attract prey.
E) There was no negative consequence.

Answer 10

A) Silent males are unable to attract mates.

Question 11

In the previous question, you were asked to identify a negative consequence for males unable
Chapter 6: Evolution and Adaptation
3
to produce mating calls. What additional adaptive response emerged in the population that
offset the negative consequence of silence?
A) Silent males also displayed more striking coloration than their singing counterparts.
B) Silent males also engaged in more active flight displays than their singing counterparts.
C) Silent males also spent more time chasing receptive females than their singing
counterparts.
D) Silent males also tended to aggregate around singing males that attracted females with
their calls.
E) Silent males exhibited all of the above adaptive responses.

Answer 11

D) Silent males also tended to aggregate around singing males that attracted females with
their calls.

Question 12

Which of the following types of selection serves as a kind of genetic housekeeping, sweeping
away harmful genetic variation?
A) stabilizing selection D) all of the above
B) directional selection E) none of the above
C) disruptive selection

Answer 12

A) stabilizing selection

Question 13

Which of the following types of selection results in the distribution of phenotypes in a
population shifting toward a new optimum?
A) stabilizing selection D) all of the above
B) directional selection E) none of the above
C) disruptive selection

Answer 13

B) directional selection

Question 14

Which of the following types of selection can lead to a bimodal distribution of phenotypes?
A) stabilizing selection D) all of the above
B) directional selection E) none of the above
C) disruptive selection

Answer 14

C) disruptive selection

Question 15

Weight at birth of human babies has a genetic component. In one large study, survival in a
cohort of babies during the first month of life was shown to be greatest for babies of average
weight at birth and least for babies with very low or very high weights at birth. Survivors of the
first month of life had lower variation in weight at birth than did all babies in the cohort.
Differential survival of this kind could result in __________ on genes controlling weight at birth.
A) stabilizing selection C) disruptive selection
B) directional selection D) no selection

Answer 15

A) stabilizing selection

Question 16

Which of the following types of selection is illustrated by the example of the peppered moth,
Biston betularia?
A) stabilizing selection D) all of the above
B) directional selection E) none of the above
C) disruptive selection

Answer 16

B) directional selection

Question 17

In his studies of the peppered moth, Biston betularia, H. B. D. Kettlewell demonstrated that the
ultimate selective agent leading to changes in genotypic frequencies was:
A) predation by birds.
B) poisoning of moths caused by industrial pollution.
C) indiscriminant use of pesticides.
D) all of the above.

Answer 17

A) predation by birds

Question 18

An interesting and gratifying footnote to the long‐term study of the peppered moth, Biston
betularia, in England has been the recent:
A) increase in the melanistic form.
B) stabilization of the melanistic form.
C) decline of the melanistic form.
D) demonstration that coloration in peppered moths has no selective value.

Answer 18

C) decline of the melanistic form.

Question 19

With the advent of pollution controls, what happened to the frequency of the melanistic form
of the peppered moth in England?
A) immediate shift to a lower frequency
B) gradual shift to a lower frequency
C) immediate shift to a higher frequency
D) gradual shift to a higher frequency
E) no change

Answer 19

B) gradual shift to a lower frequency

Question 20

During the summer months, where would you expect to find a cactus wren in early afternoon?
A) in almost any available microhabitat
B) in exposed areas with no plant cover
C) in the deep shade cast by small trees and large shrubs
D) in the nest

Answer 20

C) in the deep shade cast by small trees and large shrubs

Question 21

During the summer months, cactus wrens build nests oriented to take advantage of which of
the following?
A) prevailing afternoon breezes
B) shade cast by large saguaro cacti
C) reduced incidence of predation
D) ground cover that can break the fall of a nestling pushed from the nest

Answer 21

A) prevailing afternoon breezes

Question 22

Which of the following best defines the reaction norm?
A) the observed relationship between the phenotype of an individual and density of
conspecifics
B) the observed relationship between the phenotype of an individual and density of predators
C) the observed relationship between the phenotype of an individual and density of prey
D) the observed relationship between the phenotype of an individual and the environment

Answer 22

D) the observed relationship between the phenotype of an individual and the environment

Question 23

The larvae of swallowtail butterflies are capable of surviving and growing over a range of
temperatures. They exhibit faster growth as the environmental temperature increases. The
responsiveness of the larval phenotype to a range of environmental temperatures is referred to
as:
A) a genotype‐environment interaction. D) evolutionary fitness.
B) phenotypic plasticity. E) none of the above
C) variation in fecundity.

Answer 23

B) phenotypic plasticity

Question 24

Swallowtail butterfly larvae from Alaska and Michigan each exhibit characteristic reaction
norms for growth rate with respect to temperature. Although larvae from both populations
exhibit increasing growth rate with increasing temperature, larvae from Alaska grow faster at
lower temperatures and larvae from Michigan grow faster at higher temperatures. The specific
relationship described is referred to as:
A) a genotype‐environment interaction. D) evolutionary fitness.
B) phenotypic plasticity. E) none of the above.
C) variation in fecundity.

Answer 24

A) a genotype‐environment interaction

Question 25

When a population develops an adaptive response that results in improved performance under
the prevalent environmental conditions, a shift in the reaction norm is likely to result in
__________ performance in alternate environmental conditions.
A) improved B) reduced C) similar

Answer 25

B) reduced

Question 26

Acclimatization is a(n) __________ process.

A) reversible B) irreversible

Answer 26

A) reversible

Question 27

Of the following plants, which is likely to achieve the same maximum photosynthetic,
irrespective of the temperature to which it is acclimatized?
A) Larrea divaricata, a plant found in a seasonal climate
B) Atriplex glabriuscula, a plant found in a continuously cool climate
C) Tidestromia oblongifolia, a plant found in a continuously hot climate
D) all of the above

Answer 27

A) Larrea divaricata, a plant found in a seasonal climate

Question 28

Of the following plants, which is likely to achieve a higher maximum photosynthetic when
acclimatized at a low temperature?
A) Larrea divaricata, a plant found in a seasonal climate
B) Atriplex glabriuscula, a plant found in a continuously cool climate
C) Tidestromia oblongifolia, a plant found in a continuously hot climate
D) all of the above

Answer 28

B) Atriplex glabriuscula, a plant found in a continuously cool climate

Question 29

Of the following plants, which is likely to achieve a higher maximum photosynthetic when
acclimatized at a high temperature?
A) Larrea divaricata, a plant found in a seasonal climate
B) Atriplex glabriuscula, a plant found in a continuously cool climate
C) Tidestromia oblongifolia, a plant found in a continuously hot climate
D) all of the above

Answer 29

C) Tidestromia oblongifolia, a plant found in a continuously hot climate

Question 30

Developmental responses are __________ processes.

A) reversible B) irreversible

Answer 30

B) irreversible

Question 31

Why do individuals of the African grasshopper, Gastrimargus africanus, have pigmentation that
matches the background color of their habitat?
A) Matching coloration helps them avoid detection by would‐be predators.
B) Matching coloration minimizes absorption of solar radiation.
C) Matching coloration makes them more attractive to potential mates.
D) Matching coloration alerts fewer competitors when food is discovered.

Answer 31

A) Matching coloration helps them avoid detection by would‐be predators.

Question 32

Late in the dry season, individuals of the African grasshopper, Gastrimargus africanus, are
black. What habitat condition makes this coloration adaptive?
A) more intense sunlight
B) browning of the vegetation
C) blackening of the ground by fires
D) reduction of standing water in the habitat

Answer 32

C) blackening of the ground by fires

Question 33

Which of the following was an interesting outcome of the reciprocal transplant experiments
carried out by Niewiarowski and Roosenberg on fence lizards?
A) Native lizards and transplants from New Jersey performed equally well in Nebraska.
B) Nebraska lizards performed equally well in Nebraska and in New Jersey.
C) New Jersey lizards performed equally poorly in New Jersey and in Nebraska.
D) Each of the above was an interesting outcome of this experiment.

Answer 33

C) New Jersey lizards performed equally poorly in New Jersey and in Nebraska.

Question 34

Highbush blueberry plants belonging to a particular species grow in a wide range of
environments in North Carolina. Plants growing in acidic bogs are slower growing than plants
on fertile, better‐drained floodplains. In a reciprocal transplant study, plants from a bog were
transplanted to a floodplain and plants from a floodplain were transplanted to a bog. The
transplants from the bog performed better in the floodplain, but not as well as plants native to
the floodplain. The transplants from the floodplain performed more poorly in the bog, about
the same as plants native to the bog. What can we conclude from this experiment about the
causes of differences in growth rate between the bog and floodplain populations?
A) They are genetically determined.
B) They reflect phenotypic plasticity.
C) Both of the above conclusions are correct.

Answer 34

C) Both of the above conclusions are correct.

Question 35

The outward expression of the genotype in the individual’s structure and function is called the
__________.

Answer 35

phenotype

Question 36

Different forms of a particular gene are referred to as __________.

Answer 36

alleles

Question 37

A diploid individual that has two different alleles of a particular gene is said to be __________.

Answer 37

heterozygous

Question 38

Molecules of DNA are comprised of four kinds of subunits (adenine, thymine, cytosine, and
guanine) called __________.

Answer 38

nucleotides

Question 39

Certain mutations are referred to as __________ because the mutated coding sequence still
codes for the same amino acid as the unmutated coding sequence. Such mutations have no
consequences for fitness.

Answer 39

silent or synonymous

Question 40

A diploid individual who has two different alleles of a particular gene is said to be __________.

Answer 40

heterozygous

Question 41

The __________ of variation is the genetic basis of evolution.

Answer 41

inheritance

Question 42

__________ selection can result in a bimodal distribution of phenotypes with peaks toward
both ends of the original distribution.

Answer 42

disruptive

Question 43

Increased frequency of the dark‐colored form of the moth Biston betularia in England was
associated with industrial development leading to darkening of tree trunks. Because of this, the
increased frequency of dark moths has been dubbed __________.

Answer 43

industrial melanism

Question 44

Whether differences between populations are due to genetic differences, phenotypic plasticity,
or genotype‐environment interactions can often be revealed by __________ experiments.

Answer 44

reciprocal transplant