Chapter 20 Test Bank Answers Genes Within Populations Raven

Biology, 12e (Raven)

Chapter 20 Genes Within Populations

1) Sometimes, one gene pair will interfere with the expression of a second gene pair in an interaction called ________.

A) epistasis

B) incomplete dominance

C) codominance

D) pleiotropy

E) blending inheritance

2) By evaluating and selecting mates with superior qualities, an animal can increase its

A) reproductive success.

B) learning.

C) competitive strategies.

D) foraging efficiency.

E) length of life.

3) Natural selection for a certain phenotype will affect the ________.

A) allele frequency of a population

B) allele frequency of an individual

C) genotype of an individual

D) genotype of a population

4) When fisheries managers move fish from one lake to another, this causes gene ________.

A) blending

B) flow

C) mutation

D) dominance

5) Genotypes are said to be in ________ equilibrium if there is random mating and no other forces tend to alter the proportions of alleles from one generation to the next.

A) steady state

B) homeostatic

C) Hardy-Weinberg

D) Mendelian

6) The key point in Darwin's proposal is that the ________ imposes the conditions that determine the direction of selection.

A) parent

B) gene

C) individual

D) environment

7) The presence of the disease sickle cell anemia illustrates that natural selection does not always eliminate ________ alleles.

A) dominant

B) recessive

C) polymorphic

D) neutral

8) As a mechanism of evolution, natural selection acts on variants within populations and ultimately leads to the evolution of different species was proposed by

A) Mendel.

B) Lyell.

C) Malthus.

D) Darwin.

E) Founder.

9) Moths that can evade a bat's echolocation have ________ that increase their likelihood of survival and reproduction.

A) genes

B) fitness

C) mutations

D) adaptations

E) selection

10) In the Hardy-Weinberg equation, p and q are ________.

A) allele frequencies

B) genotypes

C) phenotypes

D) measures of fitness

E) mutation rates

11) A restriction in genetic variability caused by a drastic reduction in population size is called a

A) founder effect.

B) Hardy-Weinberg effect.

C) bottleneck effect.

D) polymorphic effect.

E) adaptive effect.

12) Reproductive success of an individual is known as:

A) variation.

B) microevolution.

C) macroevolution.

D) fitness.

E) adaptive makeup.

13) Darwin proposed that natural selection occurs in an environment by

A) favoring heritable features that make the organism better suited to survive and reproduce.

B) producing a constant number of offspring while in that environment.

C) surviving for a fixed amount of time.

D) resisting the environment and keeping the environment from changing.

E) favoring those individuals with the most favorable acquired characteristics.

14) In the Hardy-Weinberg equations, the frequencies of 2 alleles in a population (where there are only 2 alleles to consider) can be designated as

A) (p + q)2.

B) p and q.

C) p2 and q2.

D) 2pq.

E) p2 and 2pq.

15) The frequency of a particular allele within a population can be changed, over time, by

A) genetic outflow.

B) large population size.

C) selection.

D) inheritance of acquired characteristics.

E) random mating.

16) The genetic preservation of the features that increase the likelihood of survival and reproduction of some individuals within a population is called the process of

A) natural selection.

B) creation of new species.

C) genetic drift.

D) outcrossing.

E) increasing evolutionary resistance.

17) There are more than 30 blood group genes in humans, in addition to the ABO locus.  This increases ________ in human populations.

A) genetic variability

B) homozygosity

C) selective mating

D) gene flow

E) founder effects

18) Two parents who do not have sickle cell anemia have a child that has the disease.  The parents are both:

A) homozygous for the sickle cell allele.

B) heterozygous for the sickle cell allele.

C) homozygous for the normal allele.

D) epistatic for the sickle cell allele.

E) pleiotropic for the sickle cell allele.

19)

In the graph above, how can the change in infant mortality be explained as birth weight increases from 2 to 7 pounds?

A) A larger baby will have more developed organs and thus have greater fitness.

B) A baby closer to 7 pounds will not be able to be delivered safely and thus have higher mortality.

C) A baby closer to 7 pounds will have more developed organs and thus have higher mortality.

D) A baby closer to 7 pounds will have more developed organs and thus have lower mortality.

E) A baby closer to 2 pounds will not be able to be delivered safely and thus have lower mortality.

20)

In the graph above, which baby characteristics would explain the percent infant mortality curve and any subsequent effects on fitness? 

A) The baby needs to be large enough to survive after birth, but small enough for a safe delivery.

B) The larger the baby the better the chance of survival.

C) The smaller the baby the better the chance of survival.

D) The baby needs to be small enough to survive after birth, but large enough for a safe delivery.

E) There is no correlation between birth weight and survival.

21) Hardy-Weinberg pointed out that the original proportions of the genotypes in a population would remain constant from generation to generation if certain assumptions are met. Which one of the following is not a Hardy-Weinberg condition?

A) The population is very large.

B) No gene flow occurs.

C) No selection occurs.

D) Random mating occurs.

E) No polymorphic loci exist in the population.

22) For a gene with two alternative alleles, A (with a frequency of p) and B (with a frequency of q), the term in the algebraic form of the Hardy-Weinberg equilibrium for the heterozygote genotype frequency is

A) p2.

B) q2.

C) 2pq.

D) (p+q)2.

E) 2Aa.

23) The observation that most pureblood Native Americans have type O blood is best explained by ________

A) a founder effect.

B) gene flow.

C) genetic drift.

D) assortative mating.

E) frequent mutations.

24) In a small population of cockroaches living in your kitchen, only a few roaches mate in one year.  This can lead to random changes in allele frequency in the population through ________

A) mutation.

B) migration.

C) genetic drift.

D) nonrandom mating.

E) selection.

25) Female cardinals select male mates in part based on their bright red color. What effect would this have on a cardinal population that was in Hardy-Weinberg equilibrium?

A) The frequency of red alleles would be greater than those predicted by Hardy-Weinberg equilibrium.

B) The frequency of red alleles would be less than those predicted by Hardy-Weinberg equilibrium.

C) The red allele frequencies would remain unchanged because of equilibrium.

D) The frequency of red alleles would be equal to those predicted by Hardy-Weinberg equilibrium.

E) The red allele frequencies would decrease because of equilibrium.

26) You spray your kitchen with an insecticide to kill the cockroaches.  A few survive and reproduce, producing a large healthy population in a few generations that all have similar genetic backgrounds.  This is an example of ________

A) mutation.

B) migration.

C) genetic drift.

D) assortative mating.

E) bottleneck effect.

27) Gene flow, defined as the movement of genes from one population to another, can take place by migration, as well as

A) mating with certain trait-containing individuals.

B) mating with dominant phenotypes.

C) mating between individuals of adjacent populations.

D) removing the barriers between the populations.

E) physical movement of genes within an individual by transposons.

28) Some flowering plants cannot self-pollinate which increases their tendency to mate with phenotypically different mates, a process called disassortative mating.  What effect would this have on a population in Hardy-Weinberg equilibrium?

A) An increase in heterozygotes would be observed.

B) A decrease in heterozygotes would be observed.

C) An increase in homozygotes would be observed.

D) No change homozygotes or heterozygotes would be observed.

E) The population would remain in Hardy-Weinberg equilibrium.

29) ________ would keep a population in Hardy-Weinberg equilibrium.

A) Mutation

B) Gene flow

C) Random mating

D) Genetic drift

E) Selection

30) Being born with extra fingers on a hand is called polydactyly.  This is more common in some populations in North America than others due to ________.

A) a founder effect because their ancestors from Europe carried the alleles

B) an increase in mutation rate in these populations

C) random mating with other populations in North America

D) natural selection in favor of extra fingers in these populations

E) migration of people with multiple fingers out of the population

31) In order for natural selection to occur within a population, certain conditions must be met. One such condition is

A) phenotypic differences resulting from environmental conditions.

B) frequent mutations that are inherited.

C) low rates of immigration.

D) phenotypic variations that are genetic.

E) heterozygosity must be very low.

32) About 80% of the alleles present in thoroughbred horses can be dated back to 31 known ancestors from the late eighteenth century. As a result, one would expect ________

A) low rates of mutation.

B) many polymorphic alleles.

C) little variation in physiology and behavior.

D) Hardy-Weinberg equilibrium.

E) random mating.

33) In a forest, trees that get more sunlight grow taller than other nearby trees.  This is a form of ________

A) natural selection.

B) stabilizing selection.

C) disruptive selection.

D) directional selection.

E) artificial selection.

34) For a gene with two alternative alleles, B and b, the term q2 in the Hardy-Weinberg equation represents

A) the frequency of the B allele.

B) the frequency of the bb genotype.

C) the total number of individuals in the population.

D) the frequency of the Bb genotype.

E) the total number of alleles for that gene in the population.

35) Certain small towns in the western United States have remained isolated and inbred since their settlement many years ago. Some alleles are more common in these communities as compared to the rest of the population. This effect is known as

A) artificial selection.

B) directional selection.

C) disrupting selection.

D) Hardy-Weinberg principle.

E) founder effect.

36) Cheetahs have been through a genetic bottleneck; evidence for this is that

A) little natural selection occurs in this species.

B) the body is long, thin, and graceful.

C) there is very little genetic variability.

D) these cats are members of an endangered species.

E) they originally came from small areas of Africa.

37) Animals that select mates that are phenotypically similar will have ________ when compared with Hardy-Weinberg predictions.

A) fewer homozygotes

B) less natural selection

C) more heterozygotes

D) more homozygotes.

E) more mutations

38) If a population was in Hardy-Weinberg equilibrium, then ________ would occur in that population.

A) directional selection

B) assortive mating

C) natural selection

D) an increase of recessive alleles

E) no evolutionary changes

39) Large ears is a rare trait in a mainland population of mice.  A few female mice homozygous for very large ears arrive at an island that already contains mice after sneaking onto a boat. This will lead to a population with a higher incidence of big ears than the mainland population because of ________

A) a bottleneck effect.

B) gene flow.

C) increased mutation.

D) genetic drift.

E) natural selection.

40) An island is on the migration route of sea birds. This island also has abundant tree nesting birds that live on the island permanently and are not found on any other island. The tree nesting birds are more likely than the sea birds to be in Hardy-Weinberg equilibrium because: 

A) of high immigration in the sea bird population.

B) the sea bird population is larger.

C) there are fewer mutations in the sea birds.

D) mating is random in the tree nesting birds.

E) natural selection is stronger in the tree nesting birds.

41)

The percentage of different colored water boatmen eaten by fish were graphed relative to the frequency of that color in the population.  Based on the graph, a population of water boatmen would ________

A) lose rare genotypes.

B) have no variation in genotype frequencies.

C) increase in rare genotypes.

D) increase in size.

E) decrease in genetic variability.

42) In some instances environmental change causes a situation where one phenotype is favored for a period of time, and then a different phenotype is favored. This oscillating selection causes

A) the maintenance of genetic variation in the population.

B) elimination of rarer genotypes because of uneven selection.

C) an increase in point mutations.

D) high population increase to maintain phenotypic variation.

E) extinction of the population.

43) People homozygous for the sickle-cell anemia allele develop a life threatening disease, while those homozygous for the normal allele are at the highest risk of dying from malaria.  Carriers have some resistance to malaria, but do not develop sickle cell anemia.  This is an example of ________

A) founder effect.

B) genetic bottleneck.

C) point mutation.

D) heterozygote advantage.

E) heterozygosity.

44) In disruptive selection, over time

A) a population goes extinct.

B) the most extreme outliers of a population are eliminated (e.g., the largest beaks and smallest beaks are eliminated).

C) the population is strongly selected for in one direction (e.g., larger beak size).

D) the population is strongly selected for in two directions (e.g., larger beak size and smaller beak size).

E) a population increases its variation (e.g., a wide selection of all beak sizes).

45) During a drought on the Galapagos islands, finches with larger beaks were able to crack the large tough seeds produced by plants that survived the dry conditions.  This is an example of ________.

A) directional selection

B) stabilizing selection

C) disruptive selection

D) genetic drift

E) a founder effect

46) If the frequency of an autosomal recessive trait in humans is 1 out of 100 births, what would be the expected frequency of heterozygote carriers for the trait if we assume that the gene is in Hardy-Weinberg equilibrium?

A) 0.01

B) 0.10

C) 0.18

D) 0.81

E) 0.90

47) The recessive phenotype of a trait occurs in 16% of a population. What is the frequency of the dominant allele?

A) 0.16

B) 0.36

C) 0.40

D) 0.48

E) 0.60

48) A human autosomal recessive trait appears in 1 in 100 births. What percent of people are homozygous dominant for this trait?

A) 0.01

B) 0.10

C) 0.18

D) 0.81

E) 0.90

49) A population of flowers is in Hardy-Weinberg equilibrium with an allele frequency for white flowers (w) of 40%. What percentage of the flowers will have the colored or dominant phenotype?

A) 16%

B) 25%

C) 40%

D) 60%

E) 84%

50) In a large population of randomly reproducing rabbits, a recessive allele r comprises 80% of the alleles for a gene. What percentage of the rabbits would you expect to have the recessive phenotype?

A) 4%

B) 32%

C) 64%

D) 80%

E) 100%

51) You are studying a population of geese in which there are two color phases, brown and gray. Color in this species is controlled by a single gene, with brown dominant to gray. A random sample of 250 geese shows that 210 are brown. What percentage of the brown geese are heterozygous? (Assume that the population is in Hardy-Weinberg equilibrium.)

A) 36%

B) 43%

C) 48%

D) 57%

E) 84%

52) Coloration in the peppered moth (Biston betularia) is determined by a single gene with two alleles showing complete dominance. Dark moths are homozygous dominant or heterozygous for the gene, light moths are homozygous recessive. In a sample of 100 moths, you determine that 64 of the moths are dark. According to the Hardy-Weinberg rule, the expected frequency of the dominant allele is ________.

A) 0.4

B) 0.36

C) 0.6

D) 0.64

E) It cannot be determined.

53) Antigens on red blood cells are hereditary traits that allow blood to be typed in different ways. One system is based on a gene with two alleles, M and N. If the frequency of the M allele in a population is 0.4, then according to the Hardy-Weinberg rule, the expected frequency of the heterozygous MN genotype is ________.

A) 0.16

B) 0.24

C) 0.36

D) 0.48

E) 0.6

54) The disease, sickle-cell anemia is common in malaria-infested areas because individuals that are heterozygous for the gene (AS) have enhanced resistance to malaria over normal individuals (AA). Individuals with severe sickle-cell anemia (SS) usually die before reproduction. If this population moves to an area without malaria, what will happen to the allele frequency of the A allele over time?

A) It will go up because there is no malaria.

B) It will go up because there is no sickle cell anemia.

C) It will go down because there is no malaria.

D) It will go down because there is no sickle cell anemia.

55) A fur color gene in rabbits has a white dominant (W) and brown recessive allele (w).  The environment changes suddenly and none of the white rabbits survive.  In a population of 10,000 rabbits the initial frequency of W in the pool was 0.7.  How many generations would be required to eliminate all W alleles from the population? Assume that there is no mutation and the population meets all other Hardy-Weinberg conditions.

A) 1

B) 2

C) 5

D) 20

E) It can never be eliminated.

56) ________ would produce the smallest evolutionary change in a given period of time in a population of birds.

A) Mutation

B) Natural selection

C) Migration

D) Assortive mating

E) Gene flow

57) ________ could not be involved in gene flow.

A) Wind-blown pollen

B) Gametes dispersed by ocean currents

C) Zygotes dispersed by ocean currents

D) Disassortative mating within a population

E) Hybridization between neighboring populations

58) The California populations of the Northern elephant seal are descendants from a very small population of seals that was overhunted in the 1890s. Heterozygosity in this population would be expected to be ________ due to ________.

A) slight; a bottleneck effect

B) slight; the founder effect

C) great; disruptive selection

D) great; a bottleneck effect

E) great; assortive mating

59) The several hundred species of picture-winged fruit flies of the Hawaiian Islands are genetically very similar, yet they all differ markedly from their ancestral population in Asia. This is probably an example of ________

A) sexual selection.

B) directional selection.

C) disruptive selection.

D) founder effect.

E) gene flow.

60) An insect population that becomes resistant to a commonly used insecticide is an example of ________.

A) natural selection

B) genetic drift

C) disruptive selection

D) a founder effect

E) gene flow

61) The organism with the highest fitness is:

A) An animal that lives 10 years and produces 10 offspring per year.

B) An animal that lives 100 years and produces 10 offspring total.

C) An animal that lives 2 years and produces 10 offspring per year.

D) An animal that lives 10 years and produces 2 offspring per year.

E) An animal that lives one year and produces 10 offspring total.

62) A population of lizards lives in a rocky area next to a desert.  Some lizards are light colored and blend into the sand.  Others are dark and blend into the rocks.  What may happen to this population of lizards over time?

A) They may evolve into two separate species as a result of disruptive selection.

B) They may evolve into two separate species as a result of directional selection.

C) They may remain one species as a result of disruptive selection.

D) They may remain one species as a result of directional selection.

E) They may remain one species as a result of stabilizing selection.

63)

In the experiment above, guppy color patterns (spots) were measured in populations exposed to increasing amounts of predation.  From this you could conclude that ________.

A) predators are more likely to catch and eat brightly colored guppies

B) predators are less likely to catch and eat brightly colored guppies

C) brightly colored guppies are more likely to reproduce in the presence of predators

D) predators do not affect the color patterns of guppies

E) evolutionary changes take millions of years to appear

64) Both extremes of an array of phenotypes are favored in ________.

A) directional selection

B) stabilizing selection

C) disruptive selection

D) gene flow

E) genetic drift

65) In early ancestors of the modern giraffe, longer necks allowed animals to reach higher tree branches as food.  This would lead to ________ in the ancestral giraffe population.

A) directional selection

B) stabilizing selection

C) disruptive selection

D) sexual selection

E) genetic drift

66) The midrange of an array of phenotypes is favored in ________.

A) directional selection

B) stabilizing selection

C) disruptive selection

D) gene flow

E) genetic drift

67)

Based on the graph above, the color of male guppies can be seen as a balance between positive and negative selections.  Bright colors are an advantage in ________, but a disadvantage in ________.

A) attracting mates; avoiding predators

B) avoiding predators; attracting mates

C) avoiding predators; finding food

D) attracting mates; finding food

E) finding food; attracting mates

68) Many male songbirds are brightly colored.  However, the color of the birds is determined by a balance of

A) natural selection against bright colors by predation and sexual selection in favor of bright colors.

B) mutations that reduce bright colors and gene flow in favor of bright colors.

C) natural selection against bright colors by predation and mutations that introduce bright colors.

D) mutations that reduce bright colors and sexual selection in favor of bright colors.

E) gene flow that reduces bright colors and natural selection in favor of bright colors.

69) Average human males are most likely to be attracted to women with a waist to hip ratio of 0.72.  Women with this waist to hip ratio are also the most fertile.  By being attracted to women with a waist to hip ratio, a male is increasing his chances of having children and thus improve his ________.

A) fitness

B) longevity

C) allele frequency

D) gene flow

70) Select the phrases that can be associated with intersexual selection

A) mate choice

B) males fighting males to win a territory

C) peahens choosing peacocks with greater number of eyespots in their tail feathers

D) sexual selection within a sex

71) Investigate the effects of the costs of reproduction by completing the sentences.

72) Investigate sexual selection by completing the sentences.

73) Since females take on the larger parenting role in most species, what tendency do they have?

A) They produce large numbers of gametes.

B) They compete heavily for access to high fitness males.

C) They are the choosy sex.

D) They acquire polyandrous groups of male mates.

74) Pea fowl (peacocks and peahens) show sexual dimorphism -- males have long blue-green tail feathers with eyespots, while females have short brown tail feathers. Which statement best describes the graphed data about peacocks?

A) There are no peacocks with less than 140 eyespots.

B) The fewer eyespots that a peacock has in his tail, the more mates he attracts.

C) Actually eyespots have very little to do with mate-attracting activities.

D) The more eyespots that a peacock has in his tail, the more mates he attracts.

E) There are no peacocks with more than 165 eyespots.

75) A study finds a positive correlation between the number of spots on the tail of male peacocks and their mating success. What would be the best followup experiment?

A) Count the number of spots on female tails and measure mating success.

B) Remove spots or add artificial spots to male tails and determine female responses.

C) Measure the sperm count of males and compare to spot count.

D) Inject testosterone and observe changes in spot count.

76) Platys and swordtails are related tropical freshwater fish. In studies, researchers have shown that female platys prefer males with swordtails, even though males of their own species do not have them. This was discovered by attaching artificial swordtails to platys males. What does this suggest about the origin of the swordtail feature?

A) Female preference for swords may have predated the origin of the feature itself.

B) Evolution of swords later led to evolution of female preference for swords.

C) The same gene that causes sword development also causes development of neural circuits for female preference.

D) Adjacent genes on the same chromosome cause sword development and development of neural circuits for female preference.

77) Male Mormon crickets choose larger females as their mates. Which of the following statements best interprets the graph?

A) Larger females live longer and thus produce more eggs.

B) Larger females are capable of storing sperm.

C) Larger females reproduce earlier than smaller females.

D) Larger females lay more eggs.

E) Larger females defend themselves better.

78) In the phalarope, or wadepiper bird, the male is unusual in playing the larger parenting role -- he performs all the egg incubation and chick care. What unusual behavior might you predict for the female of the species?

A) The female provides sperm to fertilize the male's eggs.

B) The female is part of a large harem of females, under the domain of a single male.

C) The females compete to mate with the males, who choose among them.

D) The females have dull, brown coloring that keeps them well-camouflaged.