Deck 1: Adaptation by Natural Selection

Question 1

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.

Answer 1

A

Question 2

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.

Answer 2

B

Question 3

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.

Answer 3

C

Question 4

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.

Question 5

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.

Question 6

Adaptations are defined as the components of an organism that

A) allow it to survive and reproduce.
B) allow it to evolve more rapidly.
C) occur by random chance alone.
D) absolutely never change.

Question 7

When all females have high fecundity, a population can be driven to extinction. This occurs because of

A) natural selection.
B) convergence.
C) blending inheritance.
D) continuous variation.

Question 8

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.

Question 9

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.

Question 10

Natural selection usually acts upon and produces adaptations at the level of the

A) gene.
B) individual.
C) group.
D) species.

Question 11

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.

Question 12

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.

Question 13

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.

Question 14

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.

Question 15

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.

Question 16

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.

Question 17

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.

Question 18

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
B) trend
C) equilibrium
D) drift

Question 19

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.

Question 20

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.

Question 21

Many of Darwin's contemporaries argued that discontinuous variation is the reason that complex traits evolve. However, Darwin reasoned that discontinuous traits do not play a major role because evolution

A) happens only in large leaps.
B) occurs by singular, chance events.
C) occurs very rapidly.
D) is a gradual process.

Question 22

A South American marsupial cat and a North American placental cat existed 10,000 years ago and shared a tree shrew-like common ancestor about 120 million years before that. Both of these animals evolved a saber-toothed adaptation. What does the presence of this complex trait mean?

A) Tree shrews have saber teeth.
B) The same complex adaptation evolved twice independently.
C) Saber teeth are very common.
D) North American and South American cat populations were interbreeding.

Question 23

Discontinuous variation occurs when

A) no real variation is apparent between forms.
B) variants come in distinct forms.
C) variants come in a smooth distribution from one extreme to another.
D) only one extreme variant exists.

Question 24

In order for the medium ground finch to evolve into the large ground finch over a 46-year period, what environmental scenario would have to occur?

A) No selective pressure from the environment
B) Constant selective pressure from the environment
C) An isolated fit of extreme selective pressure from the environment followed by no selective pressure at all
D) Constantly changing selective pressure from the environment

Question 25

Continuous variation occurs when

A) no real variation is apparent between forms.
B) variants come in distinct forms.
C) variants come in a smooth distribution from one extreme to another.
D) only one extreme variant exists.

Question 26

The morphology of the marsupial wolf of Tasmania is very similar to that of the placental wolves of Eurasia. This is an example of

A) blending inheritance.
B) convergent evolution.
C) essentialism.
D) continuous variation.

Question 27

How do complex adaptations usually evolve?

A) By a single large step due to a highly adaptive mutation
B) By many small steps, but only when each is an improvement over the last step
C) By many small steps, but only when each has a minimal effect on fitness
D) By single large steps, but only when natural selection is strong

Question 28

How fast does evolution by natural selection take place?

A) It is such a slow process that a single adaptation requires millions of years.
B) It is so slow that it cannot be seen in the fossil record.
C) It is fast enough that several new species can evolve from other forms in a few million years.
D) It is so rapid that new species often evolve in a matter of decades.

Question 29

What is unique about evolution by means of artificial selection (for example, domestic dogs)?

A) It takes longer because there is no selection pressure.
B) Stabilizing selection commonly occurs.
C) Selection pressure occurs in fits and starts.
D) It can occur rapidly because selection pressure is constant.

Question 30

Achondroplasia is a genetic adaptation that causes affected individuals to be much shorter than other people. This adaptation is an example of

A) convergence.
B) gene flow.
C) discontinuous variation.
D) outbreeding.

Question 31

Discontinuous variation is unlikely to lead to new species because

A) quick changes are never found in the fossil record.
B) complex adaptations are unlikely to occur in a single jump.
C) selection cannot act on discontinuous variation.
D) it allows for only small incremental changes.

Question 32

Convergent evolution occurs

A) when all members of a species become more similar.
B) as a result of stabilizing selection.
C) when natural selection produces similar adaptations in unrelated species.
D) when individuals have equal fitness.

Question 33

Which of the following was likely the first adaptation to occur during the evolution of the human eye?

A) A protective cover and internal structures
B) A depression where information about light and light movement is collected
C) A simple, light-sensitive photo receptor
D) Neural machinery for image processing

Question 34

What does the Grants' study of medium ground finches tell us about evolution by means of natural selection?

A) New species cannot form.
B) A new species can form only when natural selection operates consistently in one direction for a few million years.
C) Evolution can change only single traits within a species.
D) New species normally take thousands to millions of years to arise because natural selection pressures operate in fits and starts.

Question 35

A complex adaptation like the human eye exists in its present form because

A) past organisms evolved and utilized a transitional form of the modern eye.
B) extreme forms of variation allowed it to evolve in a single jump.
C) it was created by a chance mutation.
D) many organisms have eyes.

Question 36

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.

Question 37

Using the rate of change that the Grants observed in the medium ground finch, and assuming a selection event only occurs once every century, how rapidly would you predict that a species of finch like the large ground finch could evolve?

A) It would take millions of years for only beak size to evolve.
B) The medium ground finch could evolve into the large ground finch in 20 years.
C) Natural selection could produce a new species of ground finch in a few thousand years.
D) Because selection generally pushes constantly in one direction, a new species of ground finch could evolve in a single century.

Question 38

Which of the following is NOT an example of how selection is able to produce complex evolutionary changes in remarkably short periods of time?

A) Using artificial selection, people intentionally created dozens of different forms of domesticated pigeons in just a few hundred years.
B) A study of fish from the genus Poeciliopsis shows that short generation times allowed three different types of placenta to evolve in less than 2.4 million years.
C) Theoretical studies of the evolution of the eye in an aquatic organism show that because of a short generation time, a complex eye could evolve in less than a million years.
D) The fossil record indicates that the human brain took 2 million years to double in size.

Question 39

Convergent evolution provides evidence that complex adaptations are not a matter of mere coincidence because

A) evolution always occurs in very different ways.
B) the same process of evolution can occur independently in unrelated species.
C) the process of evolution is biologically determined and not flexible.
D) no two species ever end up with similar traits.

Question 40

Darwin believed that when a new species arises, it does so by

A) immediately achieving a distinct, discontinuous form.
B) achieving perfection through natural selection in the first try.
C) gradually accumulating small changes.
D) following God's will.

Question 41

What is convergent evolution? Using examples from your text, explain why convergent evolution provides evidence that complex adaptations do not occur by random chance alone.

Question 42

How does natural selection produce complex, functionally integrated adaptations like the human eye?

Question 43

How has an understanding of artificial selection aided our current comprehension of natural selection?

Question 44

Based on blending inheritance, which Darwin and his contemporaries believed in, if a finch with a large beak depth mates with a finch with a small beak depth, then the offspring will have

A) beaks with small depth.
B) beaks with medium depth.
C) beaks with large depth.
D) beaks with random depth.

Question 45

What major difficulty did Darwin have with his theory of natural selection?

Question 46

When does selection produce evolutionary change relatively quickly? Provide at least two pieces of evidence to support your answer.

Question 47

Darwin could not convince his contemporaries of natural selection because

A) Darwin thought that discontinuous variation was important for evolution.
B) they believed in genetic inheritance.
C) Darwin believed in blending inheritance, which reduces variation.
D) they believed that traits were inherited from only one parent.

Question 48

Charles Darwin did not always agree with his contemporaries. What were some of his revolutionary ideas? Describe how these ideas were different from the mainstream beliefs of the nineteenth century. Lastly, discuss why we are still talking about these ideas today.

Question 49

Why was natural selection difficult for Darwin to fully explain?

A) Natural selection reduces variation.
B) Natural selection acts by removing only variants of highest fitness.
C) Natural selection acts by removing only variants of the lowest fitness.
D) Natural selection does not actually remove any variants in real life.

Question 50

What three conditions did Darwin conclude are necessary for natural selection to take place? Support your answer by either providing a real example from the chapter or coming up with a reasonable hypothetical example of how evolution operates. Be sure to discuss the role of the environment in your answer.

Question 51

Under what circumstances is selection NOT directional? Illustrate your answer with at least one example. Use your answer to explain why scientists must understand stabilizing selection in order to accurately describe evolutionary processes.

Question 52

Theoretical studies of the evolution of the eye revealed that

A) approximately 1,800 incremental changes of 1% could allow the eye to evolve from a single photo receptor to a spherical gradient lens.
B) it would take more than 10 million years for the eye to evolve in an aquatic species with a short generation time.
C) it was built by artificial selection in no more than 500 years.
D) after 1,800 changes, an eye would still be in the photo receptor phase.

Question 53

Do adaptations always benefit the group, population, or species? Why or why not? Use real or hypothetical examples to illustrate your answer.

Question 54

One of the things that Darwin had difficulty explaining was how inheritance worked. Why was inheritance so difficult for Darwin?

A) The prevailing theory of inheritance was based on random mating.
B) The prevailing theory of inheritance was incompatible with the maintenance of variation.
C) The prevailing theory of inheritance implied that variation was not inherited from parents.
D) The prevailing theory of inheritance implied that too much variation exists for natural selection to operate.

Question 55

Due to the difficulties that Darwin faced, his contemporaries continued to believe all of the following EXCEPT

A) new species arise by discontinuous variation.
B) new species arise by small steps.
C) new species arise in a single step.
D) new species can form rapidly.

Question 56

Which of the following provides an example of why Jenkin called Darwin's ideas incompatible?

A) Tall and short individuals are not able to breed with one another because they look different.
B) If tall and short individuals breed with one another, all of their offspring will be short, and variation will disappear.
C) If tall and short individuals breed with one another, all of their offspring will be tall, and variation will disappear.
D) If tall and short individuals breed with one another, all offspring will be intermediate in height, and variation will disappear.

Question 57

Why did Darwin's contemporaries believe that natural selection could not move a population beyond its initial range of variation?

A) Because selection cannot permanently change a population
B) Because selection does not produce new variants
C) Because selection can only act to stabilize variants
D) Because small increments of change are highly advantageous and cannot be bred out through blending

Question 58

Which of the following is an example of blending inheritance?

A) A tall individual marries a short individual, and all of their offspring are intermediate in height.
B) All of the domestic breeds of dogs that are alive today are descended from a wolf ancestor.
C) Offspring from two unrelated species of cats have similar saber-toothed adaptations.
D) A red-headed individual marries an individual with black hair, and all of their offspring have black hair.