Module 13 Chapter 23 Quiz Natural Selection and Evolution

Which of these variables is likely to undergo the largest change in value as the result of a mutation that introduces a brand-new allele into a population's gene pool at a locus that had formerly been fixed? A. average heterozygosity B. nucleotide variability C. geographic variability D. average number of loci

A. average heterozygosity

Use this information to answer the following questions. You are studying three populations of birds. Population A has ten birds, of which one is brown (a recessive trait) and nine are red. Population B has 100 birds, of which ten are brown. Population C has 30 birds, and three of them are brown. Which population is most likely to be subject to the bottleneck effect? A. population A B. population B C. population C D. They are all equally likely. E. It is impossible to tell from the information given.

A. population A

Adult male humans generally have deeper voices than do adult female humans, which is the direct result of higher levels of testosterone causing growth of the larynx. If the fossil records of apes and humans alike show a trend toward decreasing larynx size in adult females and increasing larynx size in adult males, then A. sexual dimorphism was developing over time in these species. B. intrasexual selection seems to have occurred. C. stabilizing selection was occurring in these species concerning larynx size. D. selection was acting more directly upon genotype than upon phenotype.

A. sexual dimorphism was developing over time in these species.

Whenever diploid populations are in Hardy-Weinberg equilibrium at a particular locus A. the allele's frequency should not change from one generation to the next, but its representation in homozygous and heterozygous genotypes may change. B. natural selection, gene flow, and genetic drift are acting equally to change an allele's frequency. C. this means that, at this locus, two alleles are present in equal proportions. D. the population itself is not evolving, but individuals within the population may be evolving.

A. the allele's frequency should not change from one generation to the next, but its representation in homozygous and heterozygous genotypes may change.

Which statement about the beak size of finches on the island of Daphne Major during prolonged drought is true? A. Each bird evolved a deeper, stronger beak as the drought persisted. B. Each bird's survival was strongly influenced by the depth and strength of its beak as the drought persisted. C. Each bird that survived the drought produced only offspring with deeper, stronger beaks than seen in the previous generation. D. The frequency of the strong-beak alleles increased in each bird as the drought persisted.

B. Each bird's survival was strongly influenced by the depth and strength of its beak as the drought persisted.

In the formula for determining a population's genotype frequencies, the 2 in the term 2pq is necessary because A. the population is diploid. B. heterozygotes can come about in two ways. C. the population is doubling in number. D. heterozygotes have two alleles.

B. heterozygotes can come about in two ways.

Use this information to answer the following questions. You are studying three populations of birds. Population A has ten birds, of which one is brown (a recessive trait) and nine are red. Population B has 100 birds, of which ten are brown. Population C has 30 birds, and three of them are brown. In which population would it be least likely that an accident would significantly alter the frequency of the brown allele? A. population A B. population B C. population C D. They are all the same. E. It is impossible to tell from the information given.

B. population B

Heterozygote advantage should be most closely linked to which of the following? A. sexual selection B. stabilizing selection C. random selection D. directional selection E. disruptive selection

B. stabilizing selection

In a very large population, a quantitative trait has the following distribution pattern: What is true of the trait whose frequency distribution in a large population appears in the previous figure? It has probably undergone A. directional selection. B. stabilizing selection. C. disruptive selection. D. normal selection.

B. stabilizing selection.

If, on average, 46% of the loci in a species' gene pool are heterozygous, then the average homozygosity of the species should be A. 23%. B. 46%. C. 54%. D.There is not enough information to say.

C. 54%.

Which of the following is a true statement concerning genetic variation? A. It is created by the direct action of natural selection. B. It arises in response to changes in the environment. C. It must be present in a population before natural selection can act upon the population. D. It tends to be reduced by the processes involved when diploid organisms produce gametes. E. A population that has a higher average heterozygosity has less genetic variation than one with a lower average heterozygosity.

C. It must be present in a population before natural selection can act upon the population.

During an individual organism's lifetime, which of these is most likely to help the organism respond properly to changes in its environment? A. microevolution B. change in allele or gene frequency C. change in gene expression D. change in average heterozygosity

C. change in gene expression

The recessive allele that causes phenylketonuria (PKU) is harmful, except when an infant's diet lacks the amino acid phenylalanine. What maintains the presence of this harmful allele in a population's gene pool? A. heterozygote advantage B. stabilizing selection C. diploidy D. balancing selection

C. diploidy

Although each of the following has a better chance of influencing gene frequencies in small populations than in large populations, which one most consistently requires a small population as a precondition for its occurrence? A. mutation B. nonrandom mating C. genetic drift D. natural selection E. gene flow

C. genetic drift

Most Swiss starlings produce four to five eggs in each clutch. Starlings producing fewer, or more, than this have reduced fitness. Which of the following terms best describes this situation? A. artificial selection B. directional selection C. stabilizing selection D. disruptive selection E. sexual selection

C. stabilizing selection

No two people are genetically identical, except for identical twins. The main source of genetic variation among human individuals is A. new mutations that occurred in the preceding generation. B. genetic drift due to the small size of the population. C. the reshuffling of alleles in sexual reproduction. D. geographic variation within the population. E. environmental effects.

C. the reshuffling of alleles in sexual reproduction.

In peas, a gene controls flower color such that R = purple and r = white. In an isolated pea patch, there are 36 purple-flowering plants and 64 white-flowering plants. Assuming Hardy-Weinberg equilibrium, what is the value of q for this population? A. 0.36 B. 0.64 C. 0.75 D. 0.80

D. 0.80

In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.1. What is the frequency of individuals with AA genotype? A. 0.20 B. 0.32 C. 0.42 D. 0.81 E. Genotype frequency cannot be determined from the information provided.

D. 0.81

In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of the allele a is 0.3. What is the percentage of the population that is homozygous for this allele? A. 0.09 B. 0.49 C. 0.9 D. 9.0 E. 49.0

D. 9.0

Which of the following statements best summarizes evolution as it is viewed today? A. It represents the result of selection for acquired characteristics. B. It is synonymous with the process of gene flow. C. It is the descent of humans from the present-day great apes. D. It is the differential survival and reproduction of the most-fit phenotypes.

D. It is the differential survival and reproduction of the most-fit phenotypes.

Over time, the movement of people on Earth has steadily increased. This has altered the course of human evolution by increasing A. nonrandom mating. B. geographic isolation. C. genetic drift. D. gene flow.

D. gene flow.

Swine are vulnerable to infection by bird flu virus and human flu virus, which can both be present in an individual pig at the same time. When this occurs, it is possible for genes from bird flu virus and human flu virus to be combined, thereby producing a genetically distinctive virus, which can subsequently cause widespread disease. The production of new types of flu virus in the manner described above is most similar to the phenomenon of A. bottleneck effect. B. founder effect. C. natural selection. D. gene flow. E. sexual selection.

D. gene flow.

In the formula for determining a population's genotype frequencies, the pq in the term 2pq is necessary because A. the population is diploid. B. heterozygotes can come about in two ways. C. the population is doubling in number. D. heterozygotes have two alleles.

D. heterozygotes have two alleles.

Sexual dimorphism is most often a result of A. pansexual selection. B. stabilizing selection. C. intrasexual selection. D. intersexual selection. E. artificial selection.

D. intersexual selection.

In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.2. What is the percentage of the population that is heterozygous for this allele? A. 0.2 B. 2.0 C. 4.0 D. 16.0 E. 32.0

E. 32.0

Natural selection changes allele frequencies because some ________ survive and reproduce more successfully than others. A. alleles B. loci C. gene pools D. species E. individuals

E. individuals

In modern terminology, diversity is understood to be a result of genetic variation. Which of the following is a recognized source of variation for evolution? A. mistakes in translation of structural genes B. mistakes in protein folding C. rampant changes to the dictionary of the genetic code D. binary fission E. recombination by crossing over in meiosis

E. recombination by crossing over in meiosis

Sparrows with average-sized wings survive severe storms better than those with longer or shorter wings, illustrating A. the bottleneck effect. B. disruptive selection. C. frequency-dependent selection. D. neutral variation. E. stabilizing selection.

E. stabilizing selection.