Deck 13: How Populations Evolve

Question 1

Which of the following statements regarding the currently available fossil record is false?

A)The currently available fossil record shows that the earliest fossils of life are about 3.5 billion years old.
B)The currently available fossil record shows that younger strata were laid down on top of older strata.
C)The currently available fossil record documents gradual evolutionary changes that link one group of organisms to another.
D)The currently available fossil record shows that the first life-forms were eukaryotes.

Answer 1

D

Question 2

The core theme of biology, which explains both the unity and diversity of life, is

A)genetics.
B)ecology.
C)evolution.
D)metabolism.

Answer 2

C

Question 3

Blue-footed boobies have webbed feet and are comically clumsy when they walk on land. Evolutionary scientists view these feet as

A)an example of a trait that is poorly adapted.
B)the outcome of a trade-off: Webbed feet perform poorly on land, but are very helpful in diving for food.
C)an example of a trait that has not evolved.
D)a curiosity that has little to teach us regarding evolution.

Answer 3

B

Question 4

Darwin found that many of the species on the Galápagos islands

A)resembled species on the nearest mainland.
B)resembled species in Europe.
C)resembled species from Australia.
D)were identical to South American species.

Question 5

A dog breeder wishes to develop a breed that does not bark. She starts with a diverse mixture of dogs. Generation after generation, she allows only the quietest dogs to breed. After 30 years of work she has a new breed of dog with interesting traits, but on average, the dogs still bark at about the same rate as other dog breeds. Which of the following would be a logical explanation for her failure?

A)There is no variation for the trait (barking).
B)The tendency to bark is not a heritable trait.
C)The selection was artificial, not natural, so it did not produce evolutionary change.
D)There was no selection (differential reproductive success)related to barking behavior.

Question 6

Which of the following statements would Darwin have disagreed with?

A)Species change over time.
B)Living species have arisen from earlier life-forms.
C)Descent with modification occurs through inheritance of acquired characteristics.
D)Descent with modification occurs by natural selection.

Question 7

Lyell's book Principles of Geology, which Darwin read on board the H.M.S. Beagle, argued in favor of which of the following concepts?

A)Earth's surface is shaped mainly by occasional catastrophic events.
B)Meteorite impacts may have been a major cause of periodic mass extinctions.
C)Earth's surface is shaped by natural forces that act gradually and are still acting.
D)The processes that shape Earth today are very different from those that were at work in the past.

Question 8

Which of the following disciplines has found evidence for evolution based on the native distributions (locations)of living species?

A)molecular biology
B)comparative anatomy
C)geographic distribution
D)paleontology

Question 9

Which of the following assumptions or observations is not part of Darwin's idea of natural selection?

A)Whether an organism survives and reproduces is almost entirely a matter of random chance.
B)Heritable traits that promote successful reproduction should gradually become more common in a population.
C)Populations produce more offspring than their environment can support.
D)Organisms compete for limited resources.

Question 10

Which of the following represents a pair of homologous structures?

A)the wing of a bat and the scales of a fish
B)the wing of a bat and the flipper of a whale
C)the antennae of an insect and the eyes of a bird
D)the wing of a bat and the wing of a butterfly

Question 11

Broccoli, cabbages, and Brussels sprouts all descend from the same wild mustard and can still interbreed. These varieties were produced by

A)artificial selection.
B)natural selection.
C)genetic drift.
D)inheritance of acquired characteristics.

Question 12

What evidence is used to determine the branching sequence of an evolutionary tree?

A)experiments in artificial selection
B)anatomical or molecular homologous structures
C)the genetic code
D)an overall assessment of general similarities between organisms

Question 13

Which of the following thinkers argued that much of human suffering was the result of human populations increasing faster than food supply, an argument that later influenced Charles Darwin's ideas of natural selection?

A)Charles Lyell
B)Thomas Malthus
C)Jean-Baptiste Lamarck
D)Gregor Mendel

Question 14

Which of the following would prevent an organism from becoming part of the fossil record when it dies?

A)It is fully decomposed by bacteria and fungi.
B)It is buried in fine sediments at the bottom of a lake.
C)It gets trapped in sap.
D)It is frozen in ice.

Question 15

Aristotle believed that

A)species evolve through natural selection and other mechanisms.
B)an individual's use of a body part causes it to further evolve.
C)species are fixed (permanent)and perfect.
D)the best evidence for change within species is seen in fossils.

Question 16

Humans share several features with salamanders. Certain genes and proteins are nearly identical between the two species; both species have four limbs with a similar skeletal structure; the species' early embryos are very similar; and where the salamander has a functional tail, humans have a vestigial tailbone. In evolutionary terms, these are examples of

A)geographic similarity.
B)homology.
C)adaptation by natural selection.
D)coincidental similarity.

Question 17

Which of the following statements regarding natural selection is false?

A)Natural selection depends on the local environment at the current time.
B)Natural selection starts with the creation of new alleles that are directed toward improving an organism's fitness.
C)Natural selection and evolutionary change can occur in a short period of time (a few generations).
D)Natural selection can be observed working in organisms alive today.

Question 18

Who developed a theory of evolution almost identical to Darwin's?

A)Lyell
B)Wallace
C)Aristotle
D)Lamarck

Question 19

During the 1950s, a scientist named Lysenko tried to solve the food shortages in the Soviet Union by breeding wheat that could grow in Siberia. He theorized that if individual wheat plants were exposed to cold, they would develop additional cold tolerance and pass it to their offspring. Based on the ideas of artificial and natural selection, do you think this project worked as planned?

A)Yes; the wheat probably evolved better cold tolerance over time through inheritance of acquired characteristics.
B)No, because Lysenko took his wheat seeds straight to Siberia instead of exposing them incrementally to cold.
C)No, because there was no process of selection based on inherited traits. Lysenko assumed that exposure could induce a plant to develop additional cold tolerance and that this tolerance would be passed to the plant's offspring.
D)Yes, because this is generally the method used by plant breeders to develop new crops.

Question 20

Which of the following best expresses the concept of natural selection?

A)differential reproductive success based on inherited characteristics
B)inheritance of acquired characteristics
C)change in response to need
D)a process of constant improvement, leading eventually to perfection

Question 21

Which of the following conditions would tend to make the Hardy-Weinberg equation more accurate for predicting the genotype frequencies of future generations in a population of a sexually reproducing species?

A)a small population size
B)little gene flow with surrounding populations
C)a tendency on the part of females to mate with the healthiest males
D)mutations that alter the gene pool

Question 22

A rabbit population consists of animals that are either very dark on top or very light on top. The color pattern is not related to sex. No rabbit shows intermediate coloration (medium darkness). This pattern might result from

A)disruptive selection.
B)directional selection.
C)stabilizing selection.
D)sexual selection.

Question 23

Microevolution, or evolution at its smallest scale, occurs when

A)an individual's traits change in response to environmental factors.
B)a community of organisms changes due to the extinction of several dominant species.
C)a new species arises from an existing species.
D)a population's allele frequencies change over a span of generations.

Question 24

The frequency of homozygous dominant individuals in a population that is in Hardy-Weinberg equilibrium is equal to

A)q or p.
B)p².
C)2pq.
D)2p.

Question 25

Which of the following statements best describes the true nature of natural selection?

A)Only the strongest survive.
B)The strong eliminate the weak in the race for survival.
C)Organisms change by random chance.
D)Heritable traits that promote reproduction become more frequent in a population from one generation to the next.

Question 26

The ultimate source of all new alleles is

A)mutation.
B)chromosomal duplication.
C)genetic drift.
D)natural selection.

Question 27

A population is

A)a group of individuals of the same species that live in the same area and interbreed.
B)all individuals of a species, regardless of location or time period in which they live.
C)a group of individuals of different species living in the same place at the same time.
D)a group of individuals of a species plus all of the other species with which they interact.

Question 28

Which of the following terms represents the frequency of heterozygotes in a population that is in Hardy-Weinberg equilibrium?

A)p
B)q
C)2pq
D)q²

Question 29

Genetic differences between populations tend to be reduced by

A)gene flow.
B)mutation.
C)the founder effect.
D)natural selection.

Question 30

A population of 1,000 birds exists on a small Pacific island. Some of the birds are yellow, a characteristic determined by a recessive allele. The others are green, a characteristic determined by a dominant allele. A hurricane on the island kills most of the birds from this population. Only 10 remain, and those birds all have yellow feathers. Which of the following statements is true?

A)Assuming that no new birds come to the island and no mutations occur, future generations of this population will contain both green and yellow birds.
B)The hurricane has caused a population bottleneck and a loss of genetic diversity.
C)This situation illustrates the effect of a mutation event.
D)The 10 remaining birds will mate only with each other, and this will contribute to gene flow in the population.

Question 31

Thirty people are selected for a long-term mission to colonize a planet many light-years away from Earth. The mission is successful, and the population rapidly grows to several hundred individuals. However, certain genetic diseases are unusually common in this group, and the group's gene pool is quite different from that of the Earth population they have left behind. Which of the following phenomena has left its mark on this population?

A)founder effect
B)bottleneck effect
C)high rates of mutation
D)natural selection

Question 32

Genetic drift resulting from a disaster that drastically reduces population size is called

A)natural selection.
B)gene flow.
C)the bottleneck effect.
D)the founder effect.

Question 33

Which of the following will tend to produce adaptive changes in populations?

A)genetic drift
B)gene flow
C)natural selection
D)the founder effect

Question 34

An elk herd is observed over many generations. Most of the full-grown bull elk have antlers of nearly the same size, although a few have antlers that are significantly larger or smaller than this average size. The average antler size remains constant over the generations. Which of the following effects probably accounts for this situation?

A)directional selection
B)stabilizing selection
C)a bottleneck effect that resulted in low genetic diversity
D)a high rate of gene flow

Question 35

After a copper smelter begins operation, local downwind populations of plants begin to adapt to the resulting air pollution. Scientists document, for example, that the acid tolerance of several plant species has increased significantly in the polluted area. This is an example of

A)stabilizing selection.
B)disruptive selection.
C)directional selection.
D)genetic drift.

Question 36

Large antlers in male elk, which are used for battles between males, are a good example of a trait favored by

A)intersexual selection.
B)intrasexual selection.
C)disruptive selection.
D)stabilizing selection.

Question 37

Darwin was the first person to draw an evolutionary tree, a diagram that represents

A)records of breeding in domesticated animals.
B)records of lineages in humans (also known as a family tree).
C)evidence-based hypotheses regarding our understanding of patterns of evolutionary descent.
D)groupings of organisms based on overall similarity.

Question 38

The recessive allele of a gene causes cystic fibrosis. For this gene among Caucasians, p = 0.98. If a Caucasian population is in Hardy-Weinberg equilibrium with respect to this gene, what proportion of babies is born homozygous recessive and therefore suffers cystic fibrosis?

A)(0.02)² = 0.0004
B)0)02
C)(0.98)² = 0.9604
D)2(0.02 × 0.98)= 0.0392

Question 39

In populations of the greater prairie chicken in Illinois, genetic diversity was

A)lost through mutation and restored by natural selection.
B)lost through genetic drift and restored by natural selection.
C)lost through gene flow and restored by mutation.
D)lost through genetic drift and restored by gene flow.

Question 40

Imagine that you are studying a very large population of moths that is isolated from gene flow. A single gene controls wing color. Half of the moths have white-spotted wings (genotype WW or Ww)and half of the moths have plain brown wings (ww). There are no new mutations, individuals mate randomly, and there is no natural selection on wing color. How will p, the frequency of the dominant allele, change over time?

A)p will increase; the dominant allele will eventually take over and become most common in the population.
B)p will neither increase nor decrease; it will remain more or less constant under the conditions described.
C)p will decrease because of genetic drift.
D)p will fluctuate rapidly and randomly because of genetic drift.

Question 41

According to this figure, which pair of organisms shares the most recent common ancestor?

A)lungfishes and amphibians
B)amphibians and lizards
C)mammals and crocodiles
D)lizards and ostriches

Question 42

The sickle-cell allele produces a serious blood disease in homozygotes. Why doesn't natural selection eliminate this allele from all human populations?

A)Natural selection is a positive force, so it does not eliminate alleles.
B)In populations where endemic malaria is present, heterozygotes have an important advantage: They are resistant to malaria and therefore are more likely to survive and produce offspring that carry the allele.
C)Mutations keep bringing the allele back into circulation.
D)Natural selection occurs very slowly, but elimination of the sickle-cell allele is expected to occur soon.

Question 43

Some of your DNA may not code for any protein and has no known function in gene regulation; it is sometimes referred to as "junk" DNA. How do nucleotide sequences of "junk DNA" evolve?

A)They evolve through natural selection.
B)They evolve through genetic drift and other chance processes.
C)They evolve to be more useful by taking on new functions.
D)They evolve by gradually being eliminated from the gene pool.

Question 44

A news article discussing the evolution of domestic dogs from wolves included this statement: "On its way from pack-hunting carnivore to fireside companion, dogs learned to love-or at least live on-wheat, rice, barley, corn, and potatoes." What is a more scientifically accurate way to state what happened with dogs?

A)Dogs mutated to be able to eat wheat, rice, barley, corn, and potatoes.
B)Some wolves may have had variants in their digestion that allowed them to eat wheat, rice, barley, corn, and potatoes and so were able to survive with humans.
C)Being around humans represented an advantage, so wolves were able to take advantage of that by changing their digestion to be able to eat wheat, rice, barley, corn, and potatoes.
D)Dogs were created at the same time as wolves.

Question 45

Mate-attracting features such as the bright plumage of a male peacock result from

A)intersexual selection.
B)intrasexual selection.
C)disruptive selection.
D)stabilizing selection.

Question 46

Which of the following statements about adaptation is true?

A)An individual that has learned how to survive cold winters has become adapted to the cold.
B)A population that has an increase in frequency of alleles for thicker fur has become adapted to the cold.
C)Adaptation results when cold temperatures cause mutations for longer fur.
D)Adaptation is possible when all the alleles in a gene pool are the same.

Question 47

Which statement best describes the mode of selection depicted in the figure?

A)stabilizing selection, changing the average color of the population over time
B)directional selection, favoring the average individual
C)directional selection, changing the average color of the population over time
D)disruptive selection, favoring the average individual

Question 48

A farmer decides to go into the business of raising trout for tourists who enjoy fishing. She builds six trout ponds and stocks each of them with trout from genetically identical stock. Her friends tell her that because she started each pond with just a few trout, she has created a bottleneck effect and her trout populations are likely to become genetically different rapidly. Which of the following statements about her trout is likely true?

A)Because they are all genetically alike, they will all remain alike even though the ponds are different.
B)Because each population started off with just a few individuals, every mutation that occurs will have a huge impact on the population, so they are likely to evolve in different directions quickly.
C)Because the ponds are different and the populations are likely to experience different mutations, the populations will likely diverge evolutionarily, but only over many generations.
D)The increase in genetic diversity caused by sexual reproduction will promote evolutionary divergence over time.

Question 49

In a large population of plants, notches in the leaves are caused by a dominant allele N and lack of notches by a recessive allele n. Over many generations the proportion of plants in the population with notched leaves increases. What is the most likely cause?

A)Dominant alleles generally increase in frequency over time.
B)The recessive alleles were all masked by the dominant alleles.
C)Directional selection favored plants with notched leaves.
D)Genetic drift caused a steady movement toward a greater proportion of plants with notched leaves.

Question 50

A woman struggling with a bacterial illness is prescribed a month's supply of a potent antibiotic. She takes the antibiotic for about two weeks and feels much better. Should she save the remaining two-week supply, or should she continue taking the drug?

A)She should save the drug for later, because if she keeps taking it the bacteria will evolve resistance.
B)She should save the drug for use the next time the illness strikes.
C)She should save the drug because antibiotics are in short supply and she may need it to defend herself against a bioterrorism incident.
D)She should continue taking the drug until her immune system can completely eliminate the infection. Otherwise, some bacteria may remain in her system, and they will probably be resistant.

Question 51

Which of the following statements regarding fins on fishes is true?

A)Fins evolved so that fish could swim better.
B)Fins came about because animals couldn't live in water without them.
C)Fins are an adaptation that aid in swimming.
D)Fins resulted from a mutation caused by a movement from land to water.

Question 52

Frequency-dependent selection, as seen in the case of the scale-eating fish in Lake Tanganyika, tends to

A)eliminate rare alleles and favor whichever allele is initially most frequent.
B)maintain two phenotypes in a dynamic equilibrium in a population.
C)produce random changes in allele frequencies.
D)stimulate new mutations.

Question 53

Which of the following would most quickly be eliminated by natural selection?

A)a harmful allele in an asexual, haploid population
B)a harmful recessive allele in a sexual, diploid population
C)a harmful recessive allele in a sexual, polyploid population
D)any harmful allele, regardless of the system of inheritance in a population

Question 54

Tay-Sachs is inherited as an autosomal recessive allele. Homozygous individuals die within the first few years of life. However, there is some evidence that heterozygous individuals are more resistant to tuberculosis. Which of the following statements about Tay-Sachs is true?

A)The allele for Tay-Sachs is selected against.
B)This situation is an example of heterozygote advantage if tuberculosis is present in a population.
C)This situation is an example of disruptive selection.
D)Heterozygotes will be more fit than either homozygote regardless of environmental conditions.

Question 55

A group of dog breeders is trying to design and develop an ideal dog. They want a dog with a gentle disposition, black fur, long ears, short legs, and a strong sense of smell. Which of the following comments from fellow dog breeders represents the biggest challenge they are likely to face?

A)There are breeds with long ears and breeds with short leg, but no breeds with both.
B)There does not seem to be any genetic variation in sense of smell.
C)Artificial selection is artificial and cannot change the genetics of a breed like natural selection.
D)Most dogs with black fur have long legs.

Question 56

If you were just diagnosed with a serious bacterial disease, which of these would predict the most positive outcome for treatment? The disease was acquired

A)in a hospital, where most of the bacteria are probably already weakened by antibiotics in the environment.
B)in a livestock barn where the animals have been treated with antibiotics.
C)in a big city where antibiotics are routinely prescribed by doctors.
D)in a remote, sparsely populated area where the bacteria have not been exposed to antibiotic drugs.

Question 57

Some butterflies can ingest toxic chemicals from the milkweed plants they feed on and then can store those chemicals in their body. Because toxins stored in the butterflies are toxic to birds, the birds avoid eating the butterflies. Which of the following is the best explanation for this situation?

A)Butterflies that stored the chemicals were never eaten by predators, so those butterflies survived.
B)Butterflies developed a mutation that led them to be able to store the chemical because they needed to avoid being eaten.
C)Milkweed plants wanted the butterflies to ingest the chemical so they would no longer feed on the plant, but the butterflies fooled the milkweed by storing the toxic chemicals.
D)Any butterfly allele that allowed milkweed toxin storage would be likely to persist because butterflies that had it were more likely to survive.

Question 58

A population of butterflies has an allele B for big spots on the wings and b for small spots on the wings. The table below provides data about this population. Genotype BB Bb bb
Number of butterflies 300 400 300
Genotype frequency 0.3 0.4 0.3
Regarding these data about the butterfly population, which of the following statements is correct?

A)The population is in Hardy-Weinberg equilibrium because the number of B alleles is equal to the number of b alleles.
B)The population is in Hardy-Weinberg equilibrium because half of the heterozygotes are B and half are b.
C)The population is not in Hardy-Weinberg equilibrium because p² and 2pq are different.
D)The population is not in Hardy-Weinberg equilibrium because the genotype frequency of bb is greater than it would be in equilibrium.

Question 59

Mothers and teachers often say they need another pair of eyes on the backs of their heads. And another pair of hands would come in handy in many situations. You can imagine that these traits would have been advantageous to our early hunter-gatherer ancestors as well. According to sound evolutionary reasoning, what is the most likely explanation for why humans do not have these traits?

A)Because they actually would not be beneficial to the fitness of individuals who possessed them. Natural selection always produces the most beneficial traits for a particular organism in a particular environment.
B)Because every time they have arisen before, the individual mutants bearing these traits have been killed by chance events. Chance and natural selection interact.
C)Because these variations have probably never appeared in a healthy human. As tetrapods, we are pretty much stuck with a four-limbed, two-eyed body plan; natural selection can only edit existing variations.
D)Because humans are a relatively young species. If we stick around and adapt for long enough, it is inevitable that the required adaptations will arise.

Question 60

Brown-eye genes are dominant over blue-eye genes. What is the best explanation for the fact that all the blue-eye alleles have not disappeared in the human population?

A)Some blue alleles are always hidden in heterozygotes.
B)The population is likely in Hardy-Weinberg equilibrium for that locus.
C)Brown-eyed people sometimes have a blue-eyed parent.
D)People with brown eyes tend to choose mates with brown eyes, and blue-eyed people tend to choose mates with blue eyes.

Question 61

After reading the paragraph below, answer the questions that follow.
Desert pupfish live in springs of the American Southwest. Today there are about 30 species of pupfish, but they all evolved from a common Pleistocene ancestor. The southwestern United States was once much wetter than it is now, and the Pleistocene pupfish flourished over a wide geographic area. Over thousands of years, however, the Sierra Nevada mountain range was pushed upward by geological forces, blocking rainfall from the Pacific Ocean. As the large lakes dried up, small groups of pupfish remained in springs and pools fed by groundwater seepage. Now, although many of these small springs still have pupfish, each population, through evolution, has become very different from populations of pupfish in other springs.
Which of the following statements represents a probable explanation for differences among pupfish populations?

A)The frequency of genotypes reached equilibrium.
B)New genes entered the population through migration.
C)The isolated populations had restricted gene pools.
D)Each new species contains all the original genotypes of the larger populations.

Question 62

After reading the paragraph below, answer the questions that follow.
Desert pupfish live in springs of the American Southwest. Today there are about 30 species of pupfish, but they all evolved from a common Pleistocene ancestor. The southwestern United States was once much wetter than it is now, and the Pleistocene pupfish flourished over a wide geographic area. Over thousands of years, however, the Sierra Nevada mountain range was pushed upward by geological forces, blocking rainfall from the Pacific Ocean. As the large lakes dried up, small groups of pupfish remained in springs and pools fed by groundwater seepage. Now, although many of these small springs still have pupfish, each population, through evolution, has become very different from populations of pupfish in other springs.
The variation in gene pools among the 30 pupfish populations occurred through an evolutionary mechanism called

A)the bottleneck effect.
B)directional selection.
C)random mating.
D)Hardy-Weinberg equilibrium.

Question 63

After reading the paragraph below, answer the questions that follow.
Desert pupfish live in springs of the American Southwest. Today there are about 30 species of pupfish, but they all evolved from a common Pleistocene ancestor. The southwestern United States was once much wetter than it is now, and the Pleistocene pupfish flourished over a wide geographic area. Over thousands of years, however, the Sierra Nevada mountain range was pushed upward by geological forces, blocking rainfall from the Pacific Ocean. As the large lakes dried up, small groups of pupfish remained in springs and pools fed by groundwater seepage. Now, although many of these small springs still have pupfish, each population, through evolution, has become very different from populations of pupfish in other springs.
If, in one population of pupfish all of the individuals have a blood pigment that is extraordinarily effective at carrying oxygen, but this trait is not seen in any of the other populations, what likely happened?

A)Because oxygen was low where these pupfish lived, a new allele for an effective blood pigment arose.
B)This population was lucky to have an individual with a random mutation for an effective blood pigment, and the frequency of this allele was increased in subsequent generations through natural selection.
C)The ancestral population probably had this type of blood pigment, but it was lost through genetic drift in the other 29 populations.
D)The other populations did not need this pigment, so they did not evolve it.

Question 64

The change in curves in the graph represents

A)a decrease in genetic variation in a population of mice.
B)the appearance of a new allele for darker color in a population of mice.
C)a shift in the range of genetic variation in a population of mice.
D)a lack of genetic variation for light fur color in the original population of mice.