Deck 13: How Populations Evolve

Question 1

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

Answer 1

C

Question 2

Aristotle believed that

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

Answer 2

A

Question 3

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

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

Answer 3

A

Question 4

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

Question 5

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)0.02² = 0.0004
B)0.98² = 0.9604
C)0.02
D)2(0.02 × 0.98)= 0.0392

Question 6

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)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.
B)No,because Lysenko took his wheat seeds straight to Siberia instead of exposing them incrementally to cold.
C)Yes,because this is generally the method used by plant breeders to develop new crops.
D)Yes,the wheat probably evolved better cold tolerance over time through inheritance of acquired characteristics.

Question 7

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

A)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.
B)Natural selection is a positive force,so it does not eliminate alleles.
C)Natural selection occurs very slowly,but elimination of the sickle- cell allele is expected to occur soon.
D)Mutations keep bringing the allele back into circulation.

Question 8

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

A)p2.
B)q or p.
C)2p.
D)2pq.

Question 9

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

Question 10

A lot of your DNA is inherited "junk": It doesn't code for any protein and has no known function in gene regulation.How do nucleotide sequences of "junk DNA" evolve?

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

Question 11

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

Question 12

Which of the following statements would Darwin have disagreed with?

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

Question 13

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

Question 14

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

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

Question 15

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

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

Question 16

Mothers and teachers have often said 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 humans are a relatively young species.If we stick around and adapt for long enough,it is inevitable that the required adaptations will arise.
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 every time they have arisen before,the individual mutants bearing these traits have been killed by chance events.Chance and natural selection interact.

Question 17

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

Question 18

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

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

Question 19

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

Question 20

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

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

Question 21

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,polyploid population
C)a harmful recessive allele in a sexual,diploid population
D)any harmful allele,regardless of the system of inheritance in a population

Question 22

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

Question 23

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

A)molecular biology
B)paleontology
C)comparative anatomy
D)biogeography

Question 24

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

Question 25

Which sentence best describes the true nature of natural selection?

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

Question 26

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

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

Question 27

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

Question 28

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

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

Question 29

Genetic differences between populations tend to be reduced by

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

Question 30

The ultimate source of all new alleles is

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

Question 31

Darwin found that many of the species on the Galápagos islands

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

Question 32

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

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

Question 33

Which of the following statements regarding natural selection is false?

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

Question 34

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

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

Question 35

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

Question 36

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 ten remain,and those birds all have yellow feathers.Which of the following statements is true?

A)This situation illustrates the effect of a mutation event.
B)The hurricane has caused a population bottleneck and a loss of genetic diversity.
C)The ten remaining birds will mate only with each other,and this will contribute to gene flow in the population.
D)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.

Question 37

Microevolution,or evolution at its smallest scale,occurs when

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

Question 38

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

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

Question 39

A population is

A)a group of individuals of a species plus all of the other species with which they interact.
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 the same species that live in the same area and interbreed.

Question 40

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

A)lungfish and amphibian
B)lizard and ostrich
C)amphibian and lizard
D)mammal and crocodile

Question 41

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

A)q
B)2pq
C)q2
D)p

Question 42

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

Question 43

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

Question 44

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

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

Question 45

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

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

Question 46

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

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

Question 47

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

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

Question 48

If you had to choose,where would you rather get infected with a serious bacterial disease?

A)In a remote,sparsely populated area where the bacteria have not been exposed to antibiotic drugs.
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 hospital,where most of the bacteria are probably already weakened by antibiotics in the environment.

Question 49

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

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

Question 50

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

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

Question 51

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