Chapter 16
77) Genetic drift is more common in large populations than in small populations.
FALSE
2) A population is defined as A) all individuals of all species located throughout the world. B) all individuals of the same species located in a given geographic region. C) all individuals of the same species located throughout the world. D) all individuals of all species located in a given country. E) those individuals of the same species that have an identical genetic makeup.
B) all individuals of the same species located in a given geographic region.
51) The change in one population driven by a change in an associated population is called A) assortative evolution. B) coevolution. C) genetic drift. D) random mutation. E) fitness.
B) coevolution.
25) The process by which allele frequencies are altered in a small population due to chance is called A) random mutation. B) genetic drift. C) random evolution. D) assortative evolution. E) fitness.
B) genetic drift.
39) Having greater evolutionary fitness means A) being stronger. B) having more offspring. C) being better able to survive. D) being able to produce more sperm or eggs. E) being larger or faster.
B) having more offspring.
47) Natural selection selects for or against certain A) gene pools. B) phenotypes. C) populations. D) alleles. E) genotypes.
B) phenotypes.
23) Habitat loss, natural catastrophes, and/or excessive harvesting of a species often result in A) increased gene flow. B) population bottlenecks. C) increased mutation rates. D) artificial selection. E) increased fitness of individuals.
B) population bottlenecks.
3) The allele frequency of a population is the A) sum of all genes in that population. B) relative proportion of a given allele in that population. C) number of different types of alleles in that population. D) number of all alleles in that population.
B) relative proportion of a given allele in that population.
49) Female finches, which do not sing, often choose to mate with males that sing a specific, elaborate song. This is an example of A) inbreeding. B) sexual selection. C) coevolution. D) assortative mating. E) fitness.
B) sexual selection.
33) Shrews have been documented to travel across frozen lakes and establish populations on previously uninhabited islands. The low level of genetic diversity in the new populations is the result of A) assortative mating. B) the founder effect. C) genetic drift. D) coevolution. E) a population bottleneck.
B) the founder effect.
27) Mutations are important because they A) usually provide an individual with increased reproductive rates. B) occur in response to environmental demands. C) provide variation that can result in evolutionary change. D) are always beneficial to the individuals affected by them.
C) provide variation that can result in evolutionary change.
46) The male peacock's beautiful tail is really a trade-off between A) disruptive selection and natural selection. B) natural selection and genetic drift. C) sexual selection and natural selection. D) artificial selection and natural selection.
C) sexual selection and natural selection.
31) Genetic drift results in a change in allele frequencies because A) gene flow within the population allows alleles to flow between populations. B) the population has not yet stabilized. C) the population size is so small that chance occurrences can alter allele frequencies. D) the population is so large that natural selection has little noticeable effect.
C) the population size is so small that chance occurrences can alter allele frequencies.
13) A population carries two alleles for a trait in which T is dominant and t is recessive. In the Hardy-Weinberg equation, 2pq represents the A) proportion of homozygous dominant individuals. B) decrease in heterozygous individuals. C) proportion of homozygous recessive individuals. D) increase in homozygous individuals. E) proportion of heterozygous individuals.
E) proportion of heterozygous individuals.
45) The elaborate courtship displays common among animals are the result of A) spontaneous mutations. B) stabilizing selection. C) random mating. D) disruptive selection. E) sexual selection.
E) sexual selection.
50) Members of one gender influence allele frequencies in a population by choosing mates according to some conspicuous feature in the other gender in the process called A) random evolution. B) fitness. C) genetic drift. D) random mutation. E) sexual selection.
E) sexual selection.
81) Natural selection causes genetic changes in an individual.
FALSE
80) Natural selection causes genetic changes in populations.
TRUE
12) According to the Hardy-Weinberg principle, if 75% of the alleles in the gene pool are A1 and 25% are A2, what is the proportion of individuals with genotype A1A2 in this population? A) 0.375 B) 0.025 C) 0.1875 D) 0.0625 E) 0.5625
A) 0.375
1) Which of the following can evolve? A) Populations B) Genes C) Individuals D) Communities
A) Populations
54) When a species lives in a constant environment for a long time, the "average type" of individual may have the best chance of surviving and producing the most offspring. What type of selection is occurring? A) Stabilizing B) Sexual C) Directional D) Artificial E) Disruptive
A) Stabilizing
36) Which of the following is an example of assortative mating? A) A female sheep chooses a mate because he has previously mated with many females. B) A female mouse chooses a mate because he is the same color that she is. C) A female lizard chooses to mate with the first male she encounters. D) A female sparrow chooses a mate because he attracts her by singing a different species' song. E) A dominant male elephant mates with most females in a group, excluding other males from mating with the females.
B) A female mouse chooses a mate because he is the same color that she is.
18) Which of the following is most likely to experience genetic drift? A) A population of bears that is growing by thousands of individuals each year B) A population of endangered birds that includes only five individuals C) A plant species that has spread to many different habitats all around the world D) A species of insect that occurs all across North America E) A population of common rodents that includes millions of individuals
B) A population of endangered birds that includes only five individuals
55) If two or more phenotypes in a population are both favored by selection, what is happening? A) Sexual selection B) Balanced polymorphism C) Directional selection D) Stabilizing selection E) Gene flow
B) Balanced polymorphism
48) As predator and prey species acquire new adaptations to help them survive the constant "arms race" between them, what evolutionary phenomenon is occurring? A) Competition B) Coevolution C) Artificial selection D) Sexual selection E) Genetic drift
B) Coevolution
20) A young male baboon leaves the troop that he was born in and joins a small neighboring troop of small baboons. He quickly rises to become a dominant male. From an evolutionary point of view, what important process has occurred? A) Nonrandom mating B) Gene flow C) The bottleneck effect D) Genetic drift E) Natural selection
B) Gene flow
24) Which of the following mutations would increase evolutionary fitness? A) One that removes other alleles from the population B) One that increases the frequency of successful reproduction C) One that increases the birth weight of offspring while decreasing the number of offspring D) One that attracts more potential mates without increasing the frequency of reproduction E) One that increases the life span of the organism
B) One that increases the frequency of successful reproduction
37) Which of the following can be measured to estimate an organism's evolutionary fitness? A) The number of eggs it produces over its lifetime B) The number of offspring it produces over its lifetime that survive to breed C) The number of offspring it produces over its lifetime D) The size of its offspring E) The number of gametes it produces over its lifetime
B) The number of offspring it produces over its lifetime that survive to breed
35) The extreme loss of genetic diversity that has occurred in cheetah populations due to overhunting is the result of A) natural selection. B) a population bottleneck. C) the founder effect. D) genetic drift. E) coevolution.
B) a population bottleneck.
62) Imagine that a mutation for red eye color becomes very common in a population of flies because female flies in this population prefer to mate with red-eyed males. This is an example of A) directional selection. B) stabilizing selection. C) disruptive selection. D) sexual selection. E) genetic drift.
D) sexual selection.
32) Evolution by genetic drift is most obvious in A) aquatic organisms. B) migratory species. C) large populations. D) small populations. E) invertebrate species.
D) small populations.
34) The Pennsylvania Amish have a very high frequency of an unusual allele that results in short arms and legs and extra fingers. This high frequency is thought to be the result of A) a population bottleneck. B) the addition of new members to an already established population. C) nonrandom mutations. D) the founder effect. E) coevolution.
D) the founder effect.
57) A new predator is introduced to an area that can feed on any millipedes shorter than 200 millimeters. No millipedes that live in that area are longer than 15 millimeters. What will happen? A) Directional selection will favor predators that consume the smallest millipedes. B) Millipedes will necessarily evolve to avoid the predator. C) The millipedes will necessarily mutate to be longer. D) Disruptive selection will favor 15-millimeter-long millipedes. E) All millipedes will be potential prey.
E) All millipedes will be potential prey.
74) In a population, the most common phenotype represents the dominant allele.
FALSE
75) Gene flow results when new individuals migrate into an area and join the breeding population there.
TRUE
78) Organisms that have the greatest reproductive success are considered the most evolutionarily fit.
TRUE
53) The type of selection most likely to act on a well-adapted population in a relatively constant environment is A) stabilizing. B) nonrandom. C) disruptive. D) directional. E) artificial.
A) stabilizing.
38) A bacterial allele that provides resistance to the antibiotic streptomycin is A) always beneficial to the bacterial cell. B) always detrimental to the cell. C) neither beneficial nor detrimental to the cell. D) beneficial to the cell in the presence of streptomycin. E) beneficial to the cell in the presence of any antibiotic.
D) beneficial to the cell in the presence of streptomycin.
8) Populations of organisms are constantly evolving, which means that they are always A) getting bigger. B) becoming more like humans. C) improving. D) changing. E) at equilibrium.
D) changing.
43) In one butterfly species, the colors of individuals range from white to black, with many shades of gray in between. If the butterflies in a mountain population become more and more similar in color over several generations (e.g., if most butterflies are the same shade of gray), what kind of evolutionary force is likely acting on the population? A) Directional selection B) Artificial selection C) Disruptive selection D) Stabilizing selection
D) Stabilizing selection
40) Male fish that display a bright blue color attract more mates as well as more predators. Maintaining that blue gene in the population is an example of A) coevolution. B) a population bottleneck. C) genetic drift. D) sexual selection. E) the founder effect.
D) sexual selection.
65) The bright coloration of male birds is often the result of A) gene flow. B) genetic drift. C) sexual selection. D) stabilizing selection. E) coevolution.
C) sexual selection.
14) A population carries two alleles for a trait in which T is dominant and t is recessive. In the Hardy-Weinberg equation, p2 represents the A) proportion of homozygous dominant individuals. B) decrease in heterozygous individuals. C) proportion of homozygous recessive individuals. D) increase in homozygous individuals. E) proportion of heterozygous individuals.
A) proportion of homozygous dominant individuals.
19) Inbreeding is defined as A) sexual reproduction among closely related individuals. B) reproduction among unrelated individuals. C) reproduction within a geographically isolated population. D) sexual reproduction in a large population. E) sexual population among unrelated individuals.
A) sexual reproduction among closely related individuals.
44) Evolution by natural selection is A) a process that occurs as a result of differences in fitness. B) a rare event that has never been observed by scientists. C) constantly occurring at the same rate in all organisms. D) currently occurring but only in scientific laboratories. E) a process that has occurred only in the past.
A) a process that occurs as a result of differences in fitness.
71) The nonliving components of an environment, such as weather and water availability, are A) abiotic components. B) alleles. C) phenotypes. D) genotypes. E) biotic components.
A) abiotic components.
5) The gene pool for a particular population is made up of A) all the genes that occur in the population. B) the sum of all the heterozygous individuals in the population. C) all the alleles for a certain trait in a given individual. D) the sum of all the homozygous individuals in the population. E) all the genes for a certain trait that occur in the population.
A) all the genes that occur in the population.
70) When natural selection tends to split a population into two phenotypic groups, it is called A) balanced polymorphism. B) genetic drift. C) stabilizing selection. D) gene flow. E) coevolution.
A) balanced polymorphism.
59) A population of hummingbirds with a variety of beak sizes finds a new food source in a plant that has a long trumpet flower with nectar at the bottom of the trumpet. Over time, these hummingbirds develop longer beaks. This is an example of A) directional selection. B) stabilizing selection. C) disruptive selection. D) sexual selection. E) genetic drift.
A) directional selection.
61) Suppose a population of mostly sand-colored crabs migrates from a sand beach to a pebble beach and evolves a darker, speckled coloration that closely resembles the pebble beach. This is an example of A) directional selection. B) stabilizing selection. C) disruptive selection. D) sexual selection. E) genetic drift.
A) directional selection.
42) In a certain species of salmon, some adult males are extremely large whereas other adult males are very small, compared to the females. There are no intermediate-sized adult males in the population. This is probably the result of A) disruptive selection. B) stabilizing selection. C) directional selection. D) artificial selection.
A) disruptive selection.
67) The net migration of alleles into or out of a population from neighboring populations is called A) gene flow. B) genetic drift. C) sexual selection. D) stabilizing selection. E) coevolution.
A) gene flow.
66) Bright coloration in birds makes them stand out to predators. In female birds that sit on the nest, bright coloration is rare. This is likely the result of A) natural selection. B) gene flow. C) stabilizing selection. D) coevolution. E) artificial mutations.
A) natural selection.
29) In general, each species of fruit fly in the Hawaiian archipelago is restricted to a single island. One hypothesis to explain this pattern is that new species formed after a small number of flies colonized each new island. This mechanism of speciation is called A) the founder effect. B) assortative mating. C) genetic equilibrium. D) artificial selection. E) sexual selection.
A) the founder effect.
68) Which of the following occurs due to chance events that change the allele frequencies in small populations? A) Gene flow B) Genetic drift C) Sexual selection D) Stabilizing selection E) Coevolution
B) Genetic drift
41) If the tallest and shortest individuals of a population of humans do not survive and reproduce as well as the individuals of "average" height, which type of selection would most likely result? A) Disruptive selection B) Artificial selection C) Stabilizing selection D) Directional selection
C) Stabilizing selection
30) Imagine a population of monkeys in South America whose habitat has been reduced to the point where only 20 individuals survive. This is an example of A) the founder effect. B) sexual selection. C) a population bottleneck. D) genetic drift. E) natural selection.
C) a population bottleneck.
26) Mutations A) are caused by natural selection. B) arise due to environmental pressures. C) can be helpful, neutral, or harmful to individuals. D) limit the potential for evolution.
C) can be helpful, neutral, or harmful to individuals.
58) A flock of birds with various beak sizes migrates to a new island where their traditional food is not available. However, there are plants that produce a variety of large nuts, which can be eaten by birds with the largest beaks, and plants that produce a variety of small, soft seeds, which can be eaten by birds with the smallest beaks. Over time, this population divides into two species with large and small beaks. This is an example of A) directional selection. B) stabilizing selection. C) disruptive selection. D) sexual selection. E) genetic drift.
C) disruptive selection.
4) The interaction of genes and environment produces a specific A) population. B) gene pool. C) phenotype. D) genotype. E) allele.
C) phenotype.
15) A population carries two alleles for a trait in which T is dominant and t is recessive. In the Hardy-Weinberg equation, q2 represents the A) proportion of homozygous dominant individuals. B) decrease in heterozygous individuals. C) proportion of homozygous recessive individuals. D) increase in homozygous individuals. E) proportion of heterozygous individuals.
C) proportion of homozygous recessive individuals.
6) In a very small population of birds, assume 5 out of 20 alleles are the type that codes for blue feathers. What is the allele frequency of the "blue feather allele" in this population? A) 0.50 B) 5 C) 0.40 D) 0.25 E) 0.20
D) 0.25
21) Zoos often loan animals to other zoos for breeding purposes. From an evolutionary standpoint, what is the benefit? A) It increases the effects of natural selection on the population. B) It increases the rate of random mutations. C) New animals increase zoo revenues. D) It increases the genetic diversity of the zoo's population. E) It creates a bottleneck effect.
D) It increases the genetic diversity of the zoo's population.
73) Which of the following can affect a small, endangered population so severely that it goes extinct? A) Sexual selection B) Artificially adding new genes C) Matings with a closely related species D) Lost alleles and/or low genetic diversity E) Increased mating opportunities
D) Lost alleles and/or low genetic diversity
9) Within a large population, if no mutations occur, no migration occurs, all matings are random, and each individual has an equal chance of reproducing, which of the following will probably happen? A) Natural selection will occur at the normal rate for that species. B) Extinction will result. C) A change in allele frequency will lead to rapid evolution. D) No evolution will occur. E) A bottleneck will occur.
D) No evolution will occur.
64) Which of the following phenomena favors individuals with average phenotypes over those with extreme phenotypes? A) Gene flow B) Genetic drift C) Sexual selection D) Stabilizing selection E) Coevolution
D) Stabilizing selection
11) In an equilibrium population A) mutation rates do not change. B) rates of gene flow are constant. C) population size cannot change. D) allele frequencies do not change. E) natural selection occurs.
D) allele frequencies do not change.
10) In the context of evolution, equilibrium means A) equal numbers of all alleles. B) equal numbers of males and females. C) no change in population size. D) no change in allele frequency. E) no individuals move into or out of the population.
D) no change in allele frequency.
52) Which trait is the best example of an adaptation? A) A shorter neck in a giraffe that lives in an area with many rival males and tall trees B) A longer tongue in an insect-eating mammal that feeds on insects that live in shallow burrows C) A new mutation that confers Tay-Sachs disease in humans D) A mutation resulting in weak branches in a species of tree that lives in windy regions E) A mutation resulting in a heat-resistant enzyme in a bacterium living in a hot spring
E) A mutation resulting in a heat-resistant enzyme in a bacterium living in a hot spring
17) Which of the following can cause evolutionary change in a small population? A) Homozygous individuals B) Lack of mutations C) Lack of gene flow D) All recessive alleles E) Genetic drift
E) Genetic drift
7) Evolution can be defined as A) a change in the phenotype of an individual over his or her lifetime. B) one species diverging into two species. C) a change in the genetic makeup of an organism over time. D) an individual changing into another species. E) a change in the genetic makeup of a population over time.
E) a change in the genetic makeup of a population over time.
72) Multidrug-resistant bacteria A) are becoming less widespread. B) are not serious threats to human health. C) have always been common in the natural environment. D) have been eradicated worldwide. E) are becoming more widespread.
E) are becoming more widespread.
56) In some butterfly populations, there are equal frequencies of alleles that code for black and yellow coloration. This is an example of A) stabilizing selection. B) directional selection. C) sexual selection. D) nonrandom mutations. E) balanced polymorphism.
E) balanced polymorphism.
28) Gene flow A) isolates populations from one another. B) negates the influence of evolution on a population. C) prevents migration of individuals into other populations. D) limits evolutionary fitness. E) can spread certain alleles throughout a species.
E) can spread certain alleles throughout a species.
63) When different species closely interact for an extended period of time and develop new adaptations in response to each other, it is called A) gene flow. B) genetic drift. C) sexual selection. D) stabilizing selection. E) coevolution.
E) coevolution.
69) When one species evolves a new phenotypic feature and another species evolves new adaptations in response, it is called A) gene flow. B) genetic drift. C) sexual selection. D) stabilizing selection. E) coevolution.
E) coevolution.
60) Suppose a new mutation that improves metabolic efficiency is lost from a small population of mammals living in a region of seasonal food scarcity after a hurricane eliminates half the mammal population. This is an example of A) directional selection. B) stabilizing selection. C) disruptive selection. D) sexual selection. E) genetic drift.
E) genetic drift.
22) The 30,000 elephant seals alive today are genetically very similar due to A) random mutation. B) natural selection. C) artificial selection. D) the founder effect. E) the bottleneck effect.
E) the bottleneck effect
16) Imagine that one of the original four mice that escape from a research lab is blind due to a genetic defect. If the escaped mouse breeds and most of the mice born in subsequent generations are blind from birth, this is most likely a case of A) selective mutation. B) an equilibrium population. C) natural selection. D) artificial selection. E) the founder effect.
E) the founder effect.
76) In a single family, the parents have brown eyes but all five of their children have green eyes. This is an example of evolution.
FALSE
79) The use of antibiotics caused the mutation that produced methicillin-resistant Staphylococcus aureus (MRSA).
FALSE
82) Environmental change causes the heritable variations in individuals that natural selection acts upon.
FALSE
83) A bird comes in a range of phenotypes, from white through gray to black. Disruptive selection favors the gray phenotype.
FALSE
