CHAPTER 1: Adaptation by Natural Selection
MULTIPLE CHOICE
1. Adaptations are defined as the components of an organism that
a. allow it to survive and reproduce. c. occur by random chance alone.
b. allow it to evolve more rapidly. d. absolutely never change.
ANS: A DIF: Medium REF: Explaining Adaptation Before Darwin
OBJ: Describe why our modern understanding of the diversity of life is based on the ideas of Charles
Darwin. MSC: Remembering
2. Which of the following is an adaptation?
a. The human eye.
b. Design by a divine creator.
c. Both the human and the fish eye, but humans are better adapted to their environments than
fish are to theirs.
d. The Grand Canyon.
ANS: A DIF: Easy REF: Explaining Adaptation Before Darwin
OBJ: Explain how natural selection can produce very complex adaptations like the human eye.
MSC: Applying
3. Influential nineteenth-century scientists like Charles Darwin concluded that the complex adaptations
we see in plants and animals are problematic and require a special explanation because
a. a divine creator designed them.
b. it is very unlikely that they arose by random chance alone.
c. they occur in most plants and animals.
d. they have no real function.
ANS: B DIF: Easy REF: Explaining Adaptation Before Darwin
OBJ: Describe why our modern understanding of the diversity of life is based on the ideas of Charles
Darwin. MSC: Understanding
4. Before Charles Darwin proposed his theory of natural selection by adaptation, many scholars argued
that adaptations are proof that
a. evolution is a process based on random chance alone.
b. because of their ability to adapt quickly, humans are better than all other species.
c. God exists and designs all things to fit a specific purpose.
d. there is no way that God can exist.
ANS: C DIF: Easy REF: Explaining Adaptation Before Darwin
OBJ: Describe why our modern understanding of the diversity of life is based on the ideas of Charles
Darwin. MSC: Remembering
5. Charles Darwin is known for his revolutionary argument that
a. plants and animals are not designed by God and do not change over time.
b. plants and animals change slowly over time.
c. fossil plants and animals changed, but existing plants and animals do not.
d. plants and animals are created by chance and then evolve through divine intervention.
ANS: B DIF: Easy REF: Darwin’s Theory of Adaptation
OBJ: Describe why our modern understanding of the diversity of life is based on the ideas of Charles
Darwin. MSC: Remembering
, 6. The postulates that make up Darwin’s theory of adaptation include all of the following EXCEPT
a. any given environment can support only a certain number of individuals.
b. variation affects the ability of individuals to survive and reproduce.
c. individuals always compete with each other physically.
d. variation is passed from parents to offspring.
ANS: C DIF: Easy REF: Darwin’s Theory of Adaptation
OBJ: Describe why our modern understanding of the diversity of life is based on the ideas of Charles
Darwin. MSC: Remembering
7. For natural selection to occur, variation must exist. This is true because without variation
a. there is no way for change to occur between generations.
b. the one trait that exists is always advantageous, and change is not necessary.
c. there is no competition among individuals.
d. traits are never inherited by offspring.
ANS: A DIF: Hard REF: Darwin’s Theory of Adaptation
OBJ: Explain how competition, variation, and heritability lead to evolution by natural selection.
MSC: Understanding
8. Even though natural selection was named after the artificial selection that plant and animal breeders
use, it really refers to
a. the survival of the physically fit.
b. the reproduction of traits from generation to generation.
c. the selective retention of variation in a population.
d. the variable ability of species to survive and reproduce.
ANS: C DIF: Hard REF: Darwin’s Theory of Adaptation
OBJ: Explain how competition, variation, and heritability lead to evolution by natural selection.
MSC: Understanding
9. During 1976 on the Galápagos Island of Daphne Major, Peter and Rosemary Grant found evidence of
natural selection by adaptation when they observed that
a. finches with shallow beaks were less likely to survive and reproduce than finches with
deep beaks.
b. finch beak size had no effect on survival rates.
c. many more small seeds were available for the finches to eat.
d. more finches with deep beaks died than finches with shallow beaks.
ANS: A DIF: Medium REF: Darwin’s Theory of Adaptation
OBJ: See why natural selection sometimes causes species to become better adapted to their
environments. MSC: Applying
10. Natural selection acted on the medium ground finch on Daphne Major because
a. birds with medium beak sizes experienced higher mortality.
b. a drought changed the environment where the finches lived.
c. offspring of finches with small beaks did not survive the juvenile period.
d. the population reached equilibrium.
ANS: B DIF: Medium REF: Darwin’s Theory of Adaptation
OBJ: See why natural selection sometimes causes species to become better adapted to their
environments. MSC: Applying
11. Which of the following is an example of directional selection?
, a. Both small and large individuals survive.
b. Only large individuals survive.
c. The proportion of small and large individuals remains the same.
d. Neither small nor large individuals survive.
ANS: B DIF: Easy REF: Darwin’s Theory of Adaptation
OBJ: Understand why natural selection can produce change or cause species to remain the same over
time. MSC: Applying
12. Which of the following is an example of stabilizing selection?
a. Both small and large individuals survive, but medium individuals die off.
b. Only large individuals survive.
c. The proportion of small and large individuals remains the same.
d. Neither small nor large individuals survive.
ANS: D DIF: Easy REF: Darwin’s Theory of Adaptation
OBJ: Understand why natural selection can produce change or cause species to remain the same over
time. MSC: Applying
13. When the Daphne Major finches reach a point where the costs of a having beak larger than average
size outweigh the benefits, beak size will begin to stay the same, and the population will achieve a(n)
________ state.
a. direction c. equilibrium
b. trend d. drift
ANS: C DIF: Easy REF: Darwin’s Theory of Adaptation
OBJ: Understand why natural selection can produce change or cause species to remain the same over
time. MSC: Remembering
14. If a population is in stasis (an unchanging state), then
a. the population is in its natural state.
b. natural selection is not acting on the population.
c. the most common type of individual is consistently favored by stabilizing selection.
d. the most common type of individual is consistently favored by disruptive selection.
ANS: C DIF: Medium REF: Darwin’s Theory of Adaptation
OBJ: Understand why natural selection can produce change or cause species to remain the same over
time. MSC: Understanding
15. After a drought, a scientist collects dead birds and finds that most of the individuals that did not
survive to adulthood have either small or large beaks. Given this pattern, how would you expect
selection to act on the population?
a. Selection will not change the mean beak size.
b. Selection will make the mean beak size in the population smaller.
c. Selection will make the mean beak size in the population larger.
d. The entire population will die out.
ANS: A DIF: Medium REF: Darwin’s Theory of Adaptation
OBJ: Understand why natural selection can produce change or cause species to remain the same over
time. MSC: Analyzing
16. Species are best described as populations of organisms that
a. are best adapted to their environment.
b. assume some fixed characteristics.
c. are dynamic.
, d. cannot be modified or go extinct.
ANS: C DIF: Medium REF: Darwin’s Theory of Adaptation
OBJ: See why natural selection usually works at the level of the individual but not at the level of the
group or species. MSC: Understanding
17. Natural selection usually acts upon and produces adaptations at the level of the
a. gene. c. group.
b. individual. d. species.
ANS: B DIF: Easy REF: Darwin’s Theory of Adaptation
OBJ: See why natural selection usually works at the level of the individual but not at the level of the
group or species. MSC: Remembering
18. Natural selection generally produces adaptations that are
a. harmful to both individuals and groups.
b. helpful to individuals but harmful to groups.
c. harmful to individuals but helpful to groups.
d. not successful unless every member of the group survives and reproduces.
ANS: B DIF: Medium REF: Darwin’s Theory of Adaptation
OBJ: See why natural selection usually works at the level of the individual but not at the level of the
group or species. MSC: Understanding
19. Fecundity is defined as the ability of
a. a population to have variation.
b. an individual to compete for resources.
c. an individual to survive to adulthood.
d. an individual to produce offspring.
ANS: D DIF: Easy REF: Darwin’s Theory of Adaptation
OBJ: See why natural selection usually works at the level of the individual but not at the level of the
group or species. MSC: Remembering
20. When all females have high fecundity, a population can be driven to extinction. This occurs because of
a. natural selection. c. blending inheritance.
b. convergence. d. continuous variation.
ANS: A DIF: Medium REF: Darwin’s Theory of Adaptation
OBJ: See why natural selection usually works at the level of the individual but not at the level of the
group or species. MSC: Applying
21. Despite its detrimental nature, cannibalism can evolve by natural selection because
a. cannibalistic groups are ferocious enough to scare predators away.
b. individuals who cannibalize have higher fitness than those who do not.
c. natural selection is always immoral.
d. cannibalistic individuals kill off the rest of their population and have no mates left to
reproduce with.
ANS: B DIF: Medium REF: Darwin’s Theory of Adaptation
OBJ: See why natural selection usually works at the level of the individual but not at the level of the
group or species. MSC: Analyzing
22. Continuous variation occurs when
a. no real variation is apparent between forms.
b. variants come in distinct forms.
MULTIPLE CHOICE
1. Adaptations are defined as the components of an organism that
a. allow it to survive and reproduce. c. occur by random chance alone.
b. allow it to evolve more rapidly. d. absolutely never change.
ANS: A DIF: Medium REF: Explaining Adaptation Before Darwin
OBJ: Describe why our modern understanding of the diversity of life is based on the ideas of Charles
Darwin. MSC: Remembering
2. Which of the following is an adaptation?
a. The human eye.
b. Design by a divine creator.
c. Both the human and the fish eye, but humans are better adapted to their environments than
fish are to theirs.
d. The Grand Canyon.
ANS: A DIF: Easy REF: Explaining Adaptation Before Darwin
OBJ: Explain how natural selection can produce very complex adaptations like the human eye.
MSC: Applying
3. Influential nineteenth-century scientists like Charles Darwin concluded that the complex adaptations
we see in plants and animals are problematic and require a special explanation because
a. a divine creator designed them.
b. it is very unlikely that they arose by random chance alone.
c. they occur in most plants and animals.
d. they have no real function.
ANS: B DIF: Easy REF: Explaining Adaptation Before Darwin
OBJ: Describe why our modern understanding of the diversity of life is based on the ideas of Charles
Darwin. MSC: Understanding
4. Before Charles Darwin proposed his theory of natural selection by adaptation, many scholars argued
that adaptations are proof that
a. evolution is a process based on random chance alone.
b. because of their ability to adapt quickly, humans are better than all other species.
c. God exists and designs all things to fit a specific purpose.
d. there is no way that God can exist.
ANS: C DIF: Easy REF: Explaining Adaptation Before Darwin
OBJ: Describe why our modern understanding of the diversity of life is based on the ideas of Charles
Darwin. MSC: Remembering
5. Charles Darwin is known for his revolutionary argument that
a. plants and animals are not designed by God and do not change over time.
b. plants and animals change slowly over time.
c. fossil plants and animals changed, but existing plants and animals do not.
d. plants and animals are created by chance and then evolve through divine intervention.
ANS: B DIF: Easy REF: Darwin’s Theory of Adaptation
OBJ: Describe why our modern understanding of the diversity of life is based on the ideas of Charles
Darwin. MSC: Remembering
, 6. The postulates that make up Darwin’s theory of adaptation include all of the following EXCEPT
a. any given environment can support only a certain number of individuals.
b. variation affects the ability of individuals to survive and reproduce.
c. individuals always compete with each other physically.
d. variation is passed from parents to offspring.
ANS: C DIF: Easy REF: Darwin’s Theory of Adaptation
OBJ: Describe why our modern understanding of the diversity of life is based on the ideas of Charles
Darwin. MSC: Remembering
7. For natural selection to occur, variation must exist. This is true because without variation
a. there is no way for change to occur between generations.
b. the one trait that exists is always advantageous, and change is not necessary.
c. there is no competition among individuals.
d. traits are never inherited by offspring.
ANS: A DIF: Hard REF: Darwin’s Theory of Adaptation
OBJ: Explain how competition, variation, and heritability lead to evolution by natural selection.
MSC: Understanding
8. Even though natural selection was named after the artificial selection that plant and animal breeders
use, it really refers to
a. the survival of the physically fit.
b. the reproduction of traits from generation to generation.
c. the selective retention of variation in a population.
d. the variable ability of species to survive and reproduce.
ANS: C DIF: Hard REF: Darwin’s Theory of Adaptation
OBJ: Explain how competition, variation, and heritability lead to evolution by natural selection.
MSC: Understanding
9. During 1976 on the Galápagos Island of Daphne Major, Peter and Rosemary Grant found evidence of
natural selection by adaptation when they observed that
a. finches with shallow beaks were less likely to survive and reproduce than finches with
deep beaks.
b. finch beak size had no effect on survival rates.
c. many more small seeds were available for the finches to eat.
d. more finches with deep beaks died than finches with shallow beaks.
ANS: A DIF: Medium REF: Darwin’s Theory of Adaptation
OBJ: See why natural selection sometimes causes species to become better adapted to their
environments. MSC: Applying
10. Natural selection acted on the medium ground finch on Daphne Major because
a. birds with medium beak sizes experienced higher mortality.
b. a drought changed the environment where the finches lived.
c. offspring of finches with small beaks did not survive the juvenile period.
d. the population reached equilibrium.
ANS: B DIF: Medium REF: Darwin’s Theory of Adaptation
OBJ: See why natural selection sometimes causes species to become better adapted to their
environments. MSC: Applying
11. Which of the following is an example of directional selection?
, a. Both small and large individuals survive.
b. Only large individuals survive.
c. The proportion of small and large individuals remains the same.
d. Neither small nor large individuals survive.
ANS: B DIF: Easy REF: Darwin’s Theory of Adaptation
OBJ: Understand why natural selection can produce change or cause species to remain the same over
time. MSC: Applying
12. Which of the following is an example of stabilizing selection?
a. Both small and large individuals survive, but medium individuals die off.
b. Only large individuals survive.
c. The proportion of small and large individuals remains the same.
d. Neither small nor large individuals survive.
ANS: D DIF: Easy REF: Darwin’s Theory of Adaptation
OBJ: Understand why natural selection can produce change or cause species to remain the same over
time. MSC: Applying
13. When the Daphne Major finches reach a point where the costs of a having beak larger than average
size outweigh the benefits, beak size will begin to stay the same, and the population will achieve a(n)
________ state.
a. direction c. equilibrium
b. trend d. drift
ANS: C DIF: Easy REF: Darwin’s Theory of Adaptation
OBJ: Understand why natural selection can produce change or cause species to remain the same over
time. MSC: Remembering
14. If a population is in stasis (an unchanging state), then
a. the population is in its natural state.
b. natural selection is not acting on the population.
c. the most common type of individual is consistently favored by stabilizing selection.
d. the most common type of individual is consistently favored by disruptive selection.
ANS: C DIF: Medium REF: Darwin’s Theory of Adaptation
OBJ: Understand why natural selection can produce change or cause species to remain the same over
time. MSC: Understanding
15. After a drought, a scientist collects dead birds and finds that most of the individuals that did not
survive to adulthood have either small or large beaks. Given this pattern, how would you expect
selection to act on the population?
a. Selection will not change the mean beak size.
b. Selection will make the mean beak size in the population smaller.
c. Selection will make the mean beak size in the population larger.
d. The entire population will die out.
ANS: A DIF: Medium REF: Darwin’s Theory of Adaptation
OBJ: Understand why natural selection can produce change or cause species to remain the same over
time. MSC: Analyzing
16. Species are best described as populations of organisms that
a. are best adapted to their environment.
b. assume some fixed characteristics.
c. are dynamic.
, d. cannot be modified or go extinct.
ANS: C DIF: Medium REF: Darwin’s Theory of Adaptation
OBJ: See why natural selection usually works at the level of the individual but not at the level of the
group or species. MSC: Understanding
17. Natural selection usually acts upon and produces adaptations at the level of the
a. gene. c. group.
b. individual. d. species.
ANS: B DIF: Easy REF: Darwin’s Theory of Adaptation
OBJ: See why natural selection usually works at the level of the individual but not at the level of the
group or species. MSC: Remembering
18. Natural selection generally produces adaptations that are
a. harmful to both individuals and groups.
b. helpful to individuals but harmful to groups.
c. harmful to individuals but helpful to groups.
d. not successful unless every member of the group survives and reproduces.
ANS: B DIF: Medium REF: Darwin’s Theory of Adaptation
OBJ: See why natural selection usually works at the level of the individual but not at the level of the
group or species. MSC: Understanding
19. Fecundity is defined as the ability of
a. a population to have variation.
b. an individual to compete for resources.
c. an individual to survive to adulthood.
d. an individual to produce offspring.
ANS: D DIF: Easy REF: Darwin’s Theory of Adaptation
OBJ: See why natural selection usually works at the level of the individual but not at the level of the
group or species. MSC: Remembering
20. When all females have high fecundity, a population can be driven to extinction. This occurs because of
a. natural selection. c. blending inheritance.
b. convergence. d. continuous variation.
ANS: A DIF: Medium REF: Darwin’s Theory of Adaptation
OBJ: See why natural selection usually works at the level of the individual but not at the level of the
group or species. MSC: Applying
21. Despite its detrimental nature, cannibalism can evolve by natural selection because
a. cannibalistic groups are ferocious enough to scare predators away.
b. individuals who cannibalize have higher fitness than those who do not.
c. natural selection is always immoral.
d. cannibalistic individuals kill off the rest of their population and have no mates left to
reproduce with.
ANS: B DIF: Medium REF: Darwin’s Theory of Adaptation
OBJ: See why natural selection usually works at the level of the individual but not at the level of the
group or species. MSC: Analyzing
22. Continuous variation occurs when
a. no real variation is apparent between forms.
b. variants come in distinct forms.
