Deck 1: Adaptation by Natural Selection

Question 1

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.

Answer 1

A

Question 2

Which of the following is an example of stabilizing selection on size?

A) Both small and large individuals survive, but medium individuals die off.
B) Only large individuals survive, thus stabilizing the species in the next generation.
C) The proportion of small and large individuals remains the same.
D) Large and small individuals are selected against to a similar degree.

Answer 2

D

Question 3

Which of the following postulates makes up Darwin's theory of adaptation?

A) The total resources in a given environment tends to expand as the number of individuals using those resources increases.
B) Only noninherited variation has a long-term impact on evolutionary change.
C) Regardless of variation in parents, genetic mixing makes offspring very similar to each other across a species.
D) Individuals vary in ways that sometimes affect survival or reproduction.

Answer 3

D

Question 4

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 5

Adaptations are defined as the components of an individual 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 6

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

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

Question 7

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 8

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 9

Charles Darwin, when developing his theory of adaptation by natural selection, incorporated the observation that

A) offspring are adapted to avoid resembling their parents in order to avoid mate confusion.
B) offspring tend to resemble their parents.
C) all competition between individuals within a species is over mates.
D) variation in offspring is shaped by the behavior of the parents during their lifetimes.

Question 10

While on the Galápagos, Darwin observed variation among finches. These observations

A) helped lead Dárwin to move away from the concept of species as unchanging entities.
B) caused Darwin to assert that the ability of a population to expand is infinite.
C) confused Darwin, but he was later informed by the Grants, who were experts on birds, what he was seeing.
D) led to Darwin's formulation of the theory of natural selection, which he published while still in the Galápagos.

Question 11

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 do you expect selection is likely acting 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 12

A key observation that Charles Darwin incorporated into his theory of adaptation by natural selection was that

A) any given environment can support only a certain number of individuals.
B) adaptations appear to arise fully formed every now and then, as a key driver of evolution.
C) individuals within a species tend to cooperate for the survival of the species.
D) no matter how limiting the resources in a given environment are, individuals can always find a way to survive.

Question 13

Even though natural selection was named after the artificial selection that plant and animal breeders use, it really refers to the

A) survival of the physically fit.
B) reproduction of traits from generation to generation.
C) selective retention of variation in a population.
D) variable ability of species to survive and reproduce.

Question 14

When the Daphne Major finches reach a point where the costs of having a 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 15

Why did natural selection act on the medium ground finch on Daphne Major?

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 16

What is the significance of the human eye in the history of research on evolution?

A) William Paley proved that since the human eye was clearly designed for seeing, it was evidence for a heavenly designer.
B) Human eyes are far more advanced than the eyes of other mammals and are an example of rapid, recent evolution.
C) Differences between human eyes and other animals' eyes are explained as different adaptations shaped by natural selection.
D) Since the human eye is made of soft tissue, and has no fossil record, the study of the eye does not inform evolutionary thinking.

Question 17

Which of the following is an example of directional selection on size?

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.

Question 18

Darwin originally went to school to become a ________ but ended up at ________ and after graduation studied ________.

A) doctor; Cambridge; natural history
B) ship's captain; Portsmouth navy yard; sailing
C) preacher; University of Edinburgh; religion
D) doctor; Harvard University; genetics

Question 19

If a population is in stasis, 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 20

Species are populations of

A) unrelated individuals that are best adapted to their environment.
B) individuals that maintain a fixed set of characteristics.
C) individuals that may vary and that may or may not change through time.
D) individuals that cannot be modified or go extinct.

Question 21

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 22

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 23

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 24

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 25

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 26

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 27

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 28

It is difficult to imagine how only part of an adaptation could function, but Darwin explained this. How would he answer the question, "What good is 5% of an eye?"

A) Once an organism has the first 5% of an adaptation, the rest will quickly evolve.
B) Five percent of an eye is always better than a full eye since it is easier to grow. The difficulty is in explaining fully formed eyes.
C) Since variation is random, we don't expect to see more than about 5% of an eye in any species.
D) Five percent of an eye, perhaps a simple light-sensitive spot, is often better than having no eye at all.

Question 29

The body 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 30

Fecundity is defined as the ability of a(n)

A) population to have variation.
B) individual to compete for resources.
C) individual to survive to adulthood.
D) individual to produce offspring.

Question 31

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

A) since they lack continuity, discontinuous traits would be rapidly selected against.
B) discontinuous traits, although common, are rarely inherited.
C) the probability of several novel mutations that work together arising at once is so high that there are mechanisms that immediately destroy them.
D) the probability of several novel mutations that work together to make a functioning trait arising all at once is almost zero.

Question 32

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 33

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 34

Despite its detrimental nature, cannibalism can evolve in a wide range of species by natural selection if

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 with which to reproduce.

Question 35

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 36

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 37

Discontinuous variation is unlikely to lead to new species because

A) rapid changes are never found in the fossil record.
B) complex adaptations require multiple simultaneous mutations that work together.
C) selection cannot act on discontinuous variation.
D) it allows for only small incremental changes.

Question 38

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 very different species.
C) the process of evolution is biologically determined and not flexible.
D) no two species ever end up with similar traits.

Question 39

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 independently in different species.
D) when individuals have equal fitness.

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

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

Question 42

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

A) small
B) medium
C) large
D) random

Question 43

Darwin proposed that three conditions of life underlie the reason that species change through time adaptively. They are as follows:

A) Populations grow beyond what the environment can handle; organisms vary; and some of the variation is genetic.
B) Populations are adapted to avoid growing beyond what the environment can handle; organisms vary; and some of the variation is genetic.
C) Populations maintain equilibrium; species are immutable; and most of the individuals in a species are the same.
D) Populations grow beyond what the environment can handle; organisms vary; and variation that is acquired in life can be passed on genetically.

Question 44

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 45

Why was natural selection difficult for Darwin to fully explain?

A) Natural selection tends to reduce variation.
B) Natural selection acts by removing only variants of the 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 46

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 47

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 48

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 49

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.

Question 50

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 51

Darwin could not convince many of 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 52

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 53

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 54

What is the difference between a fish eye and a mammal's eye, and in what way might this be explained?

A) The fish eye has only one light-bending element; the mammal eye has two. This is because the human eye is more advanced than the fish eye.
B) Fish eyes have multiple light-bending elements in order to see in water, while mammal eyes have only one.
C) The fish eye has only one light-bending element; the mammal eye has two. This allows fish to have more light-gathering ability and mammals to have greater distance vision.
D) Mammals have two light-bending elements, while the fish eye makes use of the surrounding water to act as a second "lens," so it can have only one light-bending element.

Question 55

Which of the following is an example of selection producing complex evolutionary changes in a remarkably short period of time?

A) Using artificial selection, people intentionally caused dairy cattle, which varied in their milk production, to produce the maximum amount genetically possible.
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) Richard Dawkins was able to produce most of one of Shakespeare's sonnets using only trained monkeys and small candies as rewards.
D) The fossil record indicates that the human brain took 2 million years to double in size.

Question 56

Most of Darwin's contemporaries believed

A) species evolved, and new species arise by discontinuous variation.
B) species evolved, and new species arise by small steps.
C) natural selection explained much of the variation we see in nature, even though selection actually reduces variation.
D) new species only arise by artificial selection.

Question 57

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 58

Darwin understood that

A) populations of organisms will grow until they are checked by the limited supply of resources in the environment.
B) populations of organisms will grow until individuals stop reproducing in order to control population.
C) populations of organisms maintain a steady state, just below the maximum allowed by the environment.
D) as soon as a population has filled its environment, it will evolve into a new species.

Question 59

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

Question 60

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 61

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 62

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

Question 63

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

Question 64

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