Chapter 20

In a population of seahorses, red seahorses on average produce 125 offspring and brown seahorses produce 75 offspring. What is the fitness of the brown phenotype? Multiple choice question. 1 0.6 0.4 1.4

0.6

Consider a population with 100 cats. If 72 cats are black and 28 are white, what is the phenotypic frequency of black cats? Multiple choice question. 0.14 0.72 0.56 0.36 0.28

0.72

When quantifying fitness in natural populations, the most fit phenotype is assigned a fitness value of Blank______. Multiple choice question. 100 1 2 10

1

Which evolutionary mechanism does not change allele frequencies, but changes genotype frequencies by increasing the proportion of homozygotes in the next generation? Multiple choice question. Assortative mating Genetic drift Migration Natural selection

Assortative mating

Why does selection occur? Multiple choice question. Because evolution strives to develop better traits. Because individuals move between populations and mix their genes. Because individuals must adapt to be able to survive in challenging environments. Because some individuals in a population possess more favorable phenotypes than others.

Because some individuals in a population possess more favorable phenotypes than others.

Sexual selection is a type of natural selection in which the evolution of certain traits is driven by which of the following types of competition? Multiple choice question. Competition between males and females Competition with predators Competition for mates Competition between unrelated individuals

Competition for mates

Which type of selection favors individuals at one extreme of a phenotypic range who have greater reproductive success in a particular environment? Multiple choice question. Disruptive selection Stabilizing selection Directional selection Balancing selection

Directional selection

Selection against intermediate-sized beaks in African black-bellied seedcracker finches is an example of which of the following? Multiple choice question. Oscillating selection Disruptive selection Frequency-dependent selection Stabilizing selection

Disruptive selection

Which type of selection acts to eliminate individuals which are intermediate on a phenotypic range? Multiple choice question. Directional selection Stabilizing selection Disruptive selection

Disruptive selection

What conclusion can be drawn from the observation that a population is not in Hardy-Weinberg equilibrium? Multiple choice question. Genotype frequencies but not phenotype frequencies are the same from one generation to the next. The population is isolated from other populations of the same species. Allele frequencies are stable from one generation to the next. Evolutionary forces are affecting the population.

Evolutionary forces are affecting the population.

Which of the following is true of evolutionary forces in natural populations? Multiple choice question. Evolutionary forces have no affect on allele frequencies in natural populations. Evolutionary forces are responsible for having dominant and recessive alleles for most genes. Evolutionary forces always increase the frequencies of new alleles in a natural population. Evolutionary forces can alter allele frequencies in natural populations.

Evolutionary forces can alter allele frequencies in natural populations.

Which of the following is a driving force of intersexual selection? Multiple choice question. Ability of males to escape predation Competition between males Female choice of males based on certain characteristics Males defending a territory with abundant resources

Female choice of males based on certain characteristics

What term quantifies reproductive success of a phenotype? Multiple choice question. Competition Evolution Fitness Hardy-Weinberg equilibrium

Fitness

Which of the following agents of evolutionary change occurs when alleles move from one population to another? Multiple choice question. Assortative mating Gene flow Natural selection Mutations

Gene flow

Evolutionary change is not caused by phenotypic variation if the phenotypic variation lacks which of the following? Multiple choice question. Exon shuffling Genetic basis Heterozygote Natural selection

Genetic basis

What evolutionary mechanism results in random changes in allele frequencies from one generation to the next? Multiple choice question. Nonrandom mating Natural selection Genetic drift Gene duplication Migration

Genetic drift

How does mate choice typically differ (if at all) between males and females of a species? Multiple choice question. In most animal species, both males and females choose mates randomly. In most animal species, males and females employ a similar strategy when choosing a mate. In many animal species, mate choice differs markedly in males and females.

In many animal species, mate choice differs markedly in males and females.

How does genetic drift affect allele frequencies? Multiple choice question. It increases the frequencies of beneficial alleles that are heritable. It increases the frequencies of beneficial alleles that are not heritable. It eliminates all new mutations. It changes allele frequencies randomly.

It changes allele frequencies randomly.

By favoring different phenotypes at different times, oscillating selection acts in which way? Multiple choice question. It maintains genetic variation in a population. It decreases genetic variation in a population to some extent without eliminating it completely. It completely eliminates genetic variation in a population.

It maintains genetic variation in a population.

Which of the following statements about the reproductive strategies of males and females is true? Multiple choice question. Males and females always have different reproductive strategies, regardless of the species in question. Males and females of the same species always have the same reproductive strategy. Males and females often have different reproductive strategies.

Males and females often have different reproductive strategies.

Which of the following is true about the reproductive strategies of males and females? Multiple choice question. Males are selective in choosing a mate much less frequently than females. Males are selective in choosing a mate much more frequently than females. Males are selective in choosing a mate about as frequently as females.

Males are selective in choosing a mate much less frequently than females.

What is the ultimate source of all new alleles? Multiple choice question. Natural selection Genetic drift Nonrandom mating Mutation

Mutation

Which evolutionary mechanism causes beneficial traits that are heritable to become more common in a population? Multiple choice question. Horizontal gene transfer Natural selection Genetic drift Nonrandom mating Migration

Natural selection

If we find evidence that a population is experiencing changes in allele frequencies from one generation to the next, we say that this population is which of the following? Multiple choice question. Not evolving Not in Hardy-Weinberg equilibrium Increasing in size In Hardy-Weinberg equilibrium

Not in Hardy-Weinberg equilibrium

In Northeastern South America, which of the following is the main predator in streams found just below waterfalls? Multiple choice question. Killifish Guppies Pike cichlids

Pike cichlids

A deer's antlers, a ram's horns and the bright plumage of a male paradise bird are all examples of which of the following? Multiple choice question. Secondary sexual characteristics Sperm competition Primary sexual characteristics Intersexual selection

Secondary sexual characteristics

Which type of selection favors individuals with intermediate phenotypes and selects against individuals with extreme phenotypes? Multiple choice question. Diversifying selection Sexual selection Directional selection Stabilizing selection

Stabilizing selection

Which of the following statements describes frequency-dependent selection? Multiple choice question. The fitness of a phenotype depends on the frequency of matings between individuals with that phenotype. The fitness of a phenotype depends on its frequency in the population. The fitness of a phenotype depends on the frequency of mutations leading to that phenotype.

The fitness of a phenotype depends on its frequency in the population.

The most fit phenotype produces, on average, which of the following? Multiple choice question. The healthiest offspring The most physically fit offspring The greatest number of surviving offspring

The greatest number of surviving offspring

What appears to determine variations in the coloration, size and maturation of guppies in northeastern South American streams? Multiple choice question. The relative proportion of sunlight and shade The location of streams relative to waterfalls The amount of dissolved salts in the stream The temperature of the stream

The location of streams relative to waterfalls

What is gene flow? Multiple choice question. The accumulation of mutations in a gene over time. The movement of alleles into or out of a population. The change from one allele to another. The increased survival of individuals with beneficial alleles.

The movement of alleles into or out of a population.

What is fitness? Multiple choice question. The relative likelihood that a genotype will survive The ability to exercise for a prolonged period of time The relative likelihood that a genotype will contribute to the gene pool of the next generation The ability to maintain an internal environment that is suitable for cellular functions

The relative likelihood that a genotype will contribute to the gene pool of the next generation

The phenotype frequency is calculated by dividing the total number of individuals with a particular phenotype by which of the following? Multiple choice question. The total number of homozygous individuals in that population The total number of heterozygous individuals in that population The total number of alleles in that population The total number of individuals in that population

The total number of individuals in that population

What can likely happen to uncommon alleles in small, isolated populations as a result of genetic drift? Multiple choice question. They are likely to increase in frequency. They are likely to increase in heterozygotes. They are likely to be lost. They are likely to form the next generation.

They are likely to be lost.

Which describes male guppies located below South American waterfalls where predation is high? Multiple choice question. They grow to larger sizes. They exhibit drab coloration. They exhibit bright coloration. They mature later.

They exhibit drab coloration.

In a laboratory experiment, researchers placed guppies in three different types of pools: no predation, low predation, and high predation. Researchers hypothesized that predation is a selective force and that large, brightly colored guppies are more conspicuous to predators. Based on that, what would you predict the guppies will look like in the pool with high predation after 10 generations? Multiple choice question. They should be very large, but not very brightly colored. They should be smaller and not very brightly colored. They should be large and brightly colored. They should be very small and very brightly colored.

They should be smaller and not very brightly colored.

Genetic variation in a population results from evolutionary forces that cause changes in Blank______. Multiple choice question. allele frequencies predatory habits population size migration rates

allele frequencies

In genes that are epistatic in nature, Blank______. Multiple choice question. an allele's selective advantage will always be different in different individuals an allele's selective advantage may vary from one individual to another based on their genotype selection on one allele would have no effect on other alleles certain alleles can never confer a selective advantage

an allele's selective advantage may vary from one individual to another based on their genotype

Consider two populations (population A and population B) of the same plant species and the gene Xx. Researchers discover that there is constant flow of the x allele from population B into population A. This allele happens to be detrimental to individuals in population A because of the local soil conditions. In this case gene flow Blank______. Multiple choice question. has a random effect on evolutionary change is strongly promoting evolutionary change appears to be constraining evolutionary change

appears to be constraining evolutionary change

When researchers raised guppies in laboratory pools with high levels of predation, the guppies in those aquariums Blank______. Multiple choice question. became smaller and drab in coloration as a result of natural selection after just 1 generation became smaller and drab in coloration as a result of natural selection after about 10 generations became larger and brighter in coloration as a result of natural selection after about 10 generations became larger and brighter in coloration as a result of natural selection after just 1 generation

became smaller and drab in coloration as a result of natural selection after about 10 generations

In theory, if mutation rates were high enough, alleles could be maintained in a population Blank______. Multiple choice question. even if the alleles are not favored by natural selection if the population size is small only if the alleles are favored by natural selection

even if the alleles are not favored by natural selection

Promoting or constraining evolutionary change via the movement of beneficial or detrimental alleles into or out of a population is an effect of Blank______. Multiple choice question. gene transfer natural selection gene flow genetic drift

gene flow

Evolution can result from any process that changes the Blank______ composition of a population. Multiple choice question. habitat age genetic male/female

genetic

In small populations, advantageous alleles may be lost and/or harmful alleles may increase in frequency, due to Blank______. Multiple choice question. random mating disassortative mating natural selection genetic drift

genetic drift

Many 19th century scientists believed that natural selection always favored an optimal form, and therefore would tend to reduce or eliminate Blank______. Multiple choice question. heterozygosity genetic variation genetic equilibrium population genetics

genetic variation

Assortative mating changes Blank______ frequencies but does not change Blank______ frequencies. Multiple choice question. genotype; allele genotype; heterozygote allele; heterozygote allele; homozygote

genotype; allele

Consider a gene with two alleles, A1 and A2. If the fitness of A1A2 individuals is higher than the fitness of both A1A1 and A2A2, we are observing Blank______. Multiple choice question. inbreeding non-random mating outbreeding heterozygote advantage

heterozygote advantage

When a population is in Hardy-Weinberg equilibrium, Blank______. Multiple choice question. no natural selection is occurring natural selection is balanced by genetic drift genetic drift quickly eliminates new mutations that arise natural selection quickly eliminates new mutations that arise

no natural selection is occurring

In nature, mutation rates are usually Blank______ to maintain alleles that are not favored in a population by natural selection. Multiple choice question. not high enough too high often able

not high enough

Ground finches with large bills are favored during times of drought, while ground finches with small bills are favored during times when water is abundant. This is an example of Blank______. Multiple choice question. balancing selection oscillating selection stabilizing selection diversifying selection

oscillating selection

In chickens, the same gene that affects a hen's comb also affects the rate at which the hen lays eggs. This is an example of Blank______. Multiple choice question. pleiotropy natural selection heterozygosity advantage artificial selection

pleiotrophy

The amount of genetic variation present in naturally occurring populations is Blank______. Multiple choice question. very little significant insignificant practically nonexistent

significant

For a population to be in Hardy-Weinberg equilibrium, Blank______. Multiple choice question. the rate of migration into the population must be greater than the rate of migration out of the population there must be no migration into or out of the population the rate of migration into the population must be less than the rate of migration out of the population the rate of migration into the population must equal the rate of migration out of the population

there must be no migration into or out of the population

As a result of epistasis, the selective advantage of an allele Blank______. Multiple choice question. would vary from one genotype to another would be the same in all genotypes would strongly depend on environmental conditions

would vary from one genotype to another