Smartbook 12- Population Genetics

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

Evolutionary forces are affecting the population.

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

Males and females often have different reproductive strategies.

What evolutionary process is occurring if individuals with certain genotypes mate with each other more commonly than would be expected on a random basis? Multiple choice question. Natural selection Nonrandom mating Genetic drift Gene flow

Nonrandom mating

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

The movement of alleles into or out of a population.

Multiple (blank) are usually responsible for most traits.

genes

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

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

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

Directional selection

Select the statement that describes nonrandom mating. Individuals with beneficial alleles are more likely to survive. Genetically similar individuals preferentially mate with each other. Alleles move from one population to another. Allele frequencies change due to random chance.

Genetically similar individuals preferentially mate with each other.

Select all that apply Select reasons why genetic variation within natural populations was a puzzle to Darwin and other scientists in the 19th century. Segregation of alleles among progeny of hybrids was not understood. Genetic variants were expected to be diluted to the point of disappearing in future generations. Scientists thought that selection should always favor an optimal form. The theory of blending inheritance predicted that genetic variation would increase.

Segregation of alleles among progeny of hybrids was not understood. Scientists thought that selection should always favor an optimal form. Genetic variants were expected to be diluted to the point of disappearing in future generations.

Recent evolutionary studies have shown that Darwin was mistaken in his belief that evolution occurred ____. at a very fast pace at a very slow pace at a variable pace (sometimes very slowly, sometimes very quickly)

at a very slow pace

The processes that lead to evolutionary change are mutations, natural selection, (blank) drift, gene flow and (blank) mating.

genetic nonrandom

Random changes in allele frequencies in small populations are known as (blank) (blank).

genetic drift

Selection occurs because some individuals in a population have more favorable (blank) than others in the same population and leave more progeny than others.

phenotypes

The theory of natural (blank) as a mechanism of evolution was proposed by Charles Darwin.

selection

(Blank) selection acts to prevent change away from an already common intermediate phenotype.

stabilizing

What type of selection acts to eliminate both extremes from an array of phenotypes? Multiple choice question. Directional Disruptive Stabilizing

stabilizing

If the frequency of heterozygotes in a population of mice is 0.48 for a particular gene, what would be the frequency of heterozygotes in future generations if the population is in Hardy-Weinberg equilibrium? Multiple choice question. 0.24 0.48 0.16 0.36

0.48

Why does selection occur? Multiple choice question. Because some individuals in a population possess more favorable phenotypes than others. 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.

Who mistakenly believed that evolution occurred at an extremely slow pace? Multiple choice question. Kimura Darwin Wallace Weinberg

Darwin

What type of selection favors individuals with phenotypes toward one end of an array of phenotypes? Multiple choice question. Stabilizing Counteracting Directional Disruptive

Directional

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

Disruptive selection

Select all that apply Select all of the following that are true about maintaining genetic variation in populations. Mutation is usually high enough to counteract natural selection. Evolutionary forces can work in opposition to change allele frequencies. Evolutionary forces can act together to change allele frequencies. Genetic drift is expected to overwhelm natural selection in large populations.

Evolutionary forces can work in opposition to change allele frequencies. Evolutionary forces can act together to change allele frequencies..

True or false: Within the same species, females and males usually employ the same reproductive strategy.

False

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

Fitness

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

Gene flow

When heterozygous advantage exists, how would you describe the fitness of the heterozygous genotype? It has higher fitness than either homozygote It has lower fitness than either homozygote It has fitness that is intermediate between that of the two homozygotes

It has higher fitness than either homozygote

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

It maintains genetic variation in a population.

Consider a gene with two alleles, one dominant, and the other recessive. If this population is in Hardy-Weinberg equilibrium with respect to this gene, what would happen to the dominant allele from generation to generation? Its frequency will slowly decrease Its frequency will remain unchanged Its frequency will slowly increase

Its frequency will remain unchanged

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

Mutation

Select all of the following processes that can cause changes in allele or genotype frequencies in populations. Multiple select question. Gene flow Genetic drift Random Mating Nonrandom Mating Natural selection Mutations

Mutations gene flow nonrandom mating genetic drift natural selection

Multiple phenotypic effects of alleles, lack of genetic variation, and interactions between genes can all limit what ______ can accomplish. Multiple choice question. SNP analysis migration Hardy-Weinberg equilibrium natural selection

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 In Hardy-Weinberg equilibrium Increasing in size Not in Hardy-Weinberg equilibrium

Not in Hardy-Weinberg equilibrium

Select all that apply Choose all the components of fitness from the list below: Body size and health Production of viable, numerous offspring Mating success Individual survival

Production of viable, numerous offspring Mating success Individual survival

What is genetic drift? Transfer of genes from one species to another Migration of individuals from one population to another Shuffling of exons of different genes to create new genes with novel functions Random changes in the allele frequencies of a population over time

Random changes in the allele frequencies of a population over time

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

The greatest number of surviving offspring

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

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

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? They should be smaller and not very brightly colored They should be very small and very brightly colored They should be very large, but not very brightly colored They should be large and brightly colored

They should be smaller and not very brightly colored

True or false: Genetic drift, mutations, and nonrandom mating are three agents that can act to produce evolutionary changes in a population.

True

Suppose that a population of finches migrates to a small island where most of the seeds are large. On the island, birds with large beaks are more likely to survive, and over time, the mean beak size of the population increases. This is an example of (blank) selection.

directional

The accumulation of differences in species that causes new species to arise from existing ones is a process called Multiple choice question. evolution. acquisition. inheritance. Hardy-Weinberg equilibrium.

evolution

The word (blank) is used to refer to how an entity, such as a species, changes over time.

evolution

In natural populations, most genes Multiple choice question. exhibit variation. are not variable. are monomorphic. possess only one allele.

exhibit variation

Consider two populations of the same plant species - population A and population B 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. This is an example of gene flow opposing genetic drift. mutation opposing natural selection. genetic drift reinforcing natural selection. gene flow opposing natural selection.

gene flow opposing natural selection.

Many 19th century scientists believed that natural selection always favored an optimal form, and therefore would tend to reduce or eliminate which of the following? Multiple choice question. Heterozygosity Equilibrium Genetic variation Population genetics

genetic variation

A situation where individuals with two different alleles at a gene locus are favored over individuals with two of the same alleles at the locus is called (blank) advantage.

heterozygous

Natural selection may be countered by mutations when mutation rates are (blank) and by genetic drift when population sizes are (blank).

high, small

Most phenotypes in nature are affected by Multiple choice question. environment only. more than one gene. a single gene. developmental processes only.

more than one gene

Most phenotypes in nature are affected by Multiple choice question. environment only. more than one gene. developmental processes only. a single gene.

more than one gene

(Blank) is the ultimate source of genetic variation.

mutation

Multiple phenotypic effects of alleles, lack of genetic variation, and interactions between genes can all limit what ______ can accomplish. Multiple choice question. SNP analysis Hardy-Weinberg equilibrium natural selection migration

natural selection

The guppy, which lives in streams above and below waterfalls in northeastern South America, has been the subject of recent lab and field studies demonstrating natural selection. inbreeding. the founder effect. mutation rates.

natural selection

The process in which beneficial traits that are heritable become more common in successive generations is called ____. Multiple choice question. natural selection random mating gene flow genetic drift

natural selection

A type of natural selection called (blank) selection favors different phenotypes at different times and maintains (blank) variation in populations.

oscillating genetic

Select all that apply Select all of the following factors that limit what selection can accomplish. pleiotropy interactions between genes lack of genetic variation equal allele frequencies

pleiotropy interactions between genes lack of genetic variation

(Blank) selection is a type of natural selection in which competition for mates drives the evolution of certain traits.

sexual

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

significant

An example of recent experiments of evolution that have been conducted both in the lab and in the field are Multiple choice question. studies of the guppy Poecilia reticulata. studies of the fruit fly Drosophila. studies of the sickle-cell allele in humans. studies of ommatidia number in compound eyes of insects.

studies of the guppy Poecilia reticulata.

Select all that apply Fitness is a measure of Multiple select question. survival. physical strength. mating success. number of offspring produced per mating.

survival. mating success. number of offspring produced per mating.

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? Competition between males and females Competition between unrelated individuals Competition with predators Competition for mates

Competition for mates

Many 19th century scientists believed that natural selection always favored an optimal form, and therefore would tend to reduce or eliminate which of the following? Multiple choice question. Equilibrium Heterozygosity Genetic Variation Population genetics

Genetic Variation

Directional selection acts to eliminate individuals on both ends of a range of phenotypes. acts to eliminate one extreme from a range of phenotypes. acts to eliminate individuals with an intermediate phenotype.

acts to eliminate one extreme from a range of phenotypes.