Chapter 23 Practice Multiple Choice

Multiple Choice Identify the choice that best completes the statement or answers the question.

____ 1. Which of these is a statement that Darwin would have rejected? a. Environmental change plays a role in evolution. b. The smallest entity that can evolve is an individual organism. c. Individuals can acquire new characteristics as they respond to new environments or situations. d. Inherited variation in a population is a necessary precondition for natural selection to operate. e. Natural populations tend to produce more offspring than the environment can support.

____ 2. 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

____ 3. 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 developed a deeper, stronger beak as the drought persisted. c. Each bird's survival was strongly influenced by the depth and strength of its beak as the drought persisted. d. Each bird that survived the drought produced only offspring with deeper, stronger beaks than seen in the previous generation. e. The frequency of the strong-beak alleles increased in each bird as the drought persisted.

____ 4. The higher the proportion of loci that are "fixed" in a population, the lower is that population's a. nucleotide variability. b. genetic polyploidy. c. average heterozygosity. d. A, B, and C e. A and C only

____ 5. Sponges are known to contain a single Hox gene. Most invertebrates have a cluster of 10 similar Hox genes, all located on the same chromosome. Most vertebrates have four such clusters of Hox genes, located on four non-homologous chromosomes. The process responsible for the change in number of Hox genes from sponges to invertebrates was most likely ____, whereas a different process that could have potentially contributed to the cluster's presence on more than one chromosome was ____. I. binary fission II. translation III. gene duplication IV. non-disjunction V. transcription

a. I, II b. II, III c. II, V d. III, IV e. III, V

Use the following information to answer the questions below.

HIV's genome of RNA includes code for reverse transcriptase (RT), an enzyme that acts early in infection to synthesize a DNA genome off of an RNA template. The HIV genome also codes for protease (PR), an enzyme that acts later in infection by cutting long viral polyproteins into smaller, functional proteins. Both RT and PR represent potential targets for antiretroviral drugs. Drugs called nucleoside analogs (NA) act against RT, whereas drugs called protease inhibitors (PI) act against PR.

____ 6. Within the body of an HIV-infected individual who is being treated with a single NA, and whose HIV particles are currently vulnerable to this NA, which of these situations can increase the virus' relative fitness? 1. mutations resulting in RTs with decreased rates of nucleotide mismatch 2. mutations resulting in RTs with increased rates of nucleotide mismatch 3. mutations resulting in RTs that have proofreading capability a. 1 only b. 2 only c. 3 only d. 1 and 3 e. 2 and 3

____ 7. Which of these makes determining the evolutionary relatedness of different species based on the amino acid sequence of homologous proteins generally less accurate than determinations of relatedness based on the nucleotide sequences of homologous genes? a. Silent mutations b. Gene duplications c. Translocation events that change gene sequences d. Crossing-over e. Independent assortment

____ 8. Which 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 larger average heterozygosity.

Use the following information to answer the questions below.

A large population of laboratory animals has been allowed to breed randomly for a number of generations. After several generations, 25% of the animals display a recessive trait (aa), the same percentage as at the beginning of the breeding program. The rest of the animals show the dominant phenotype, with heterozygotes indistinguishable from the homozygous dominants.

____ 9. What is the estimated frequency of allele A in the gene pool? a. 0.05 b. 0.25 c. 0.50 d. 0.75 e. 1.00

____ 10. What proportion of the population is probably heterozygous (Aa) for this trait? a. 0.05 b. 0.25 c. 0.50 d. 0.75 e. 1.00

____ 11. 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 percentage of the population that is heterozygous for this allele? a. 90 b. 81 c. 49 d. 18 e. 10

The following questions refer to this information:

In the year 2500, five male space colonists and five female space colonists (all unrelated to each other) settle on an uninhabited Earthlike planet in the Andromeda galaxy. The colonists and their offspring randomly mate for generations. All ten of the original colonists had free earlobes, and two were heterozygous for that trait. The allele for free earlobes is dominant to the allele for attached earlobes.

____ 12. Which of these is closest to the allele frequency in the founding population? a. 0.1 a, 0.9 A b. 0.2 a, 0.8 A c. 0.5 a, 0.5 A d. 0.8 a, 0.2 A e. 0.4 a, 0.6 A

____ 13. If one assumes that Hardy-Weinberg equilibrium applies to the population of colonists on this planet, about how many people will have attached earlobes when the planet's population reaches 10,000? a. 100 b. 400 c. 800 d. 1,000 e. 10,000

____ 14. If the frequency of a particular allele that is present in a small, isolated population of alpine plants decreases due to a landslide that leaves an even smaller remnant of surviving plants bearing this allele, then what has occurred? a. a bottleneck b. genetic drift c. microevolution d. A and B only e. A, B, and C

____ 15. Gene flow is a concept best used to describe an exchange between a. species. b. males and females. c. populations. d. individuals. e. chromosomes.

The restriction enzymes of bacteria protect the bacteria from successful attack by bacteriophages, whose genomes can be degraded by the restriction enzymes. The bacterial genomes are not vulnerable to these restriction enzymes because bacterial DNA is methylated. This situation selects for bacteriophages whose genomes are also methylated. As new strains of resistant bacteriophages become more prevalent, this in turn selects for bacteria whose genomes are not methylated and whose restriction enzymes instead degrade methylated DNA.

____ 16. The outcome of the conflict between bacteria and bacteriophage at any point in time results from a. frequency-dependent selection. b. evolutionary imbalance. c. heterozygote advantage. d. neutral variation. e. genetic variation being preserved by diploidy.

____ 17. Over the course of evolutionary time, what should occur? a. Methylated DNA should become fixed in the gene pools of bacterial species. b. Nonmethylated DNA should become fixed in the gene pools of bacteriophages. c. Methylated DNA should become fixed in the gene pools of bacteriophages. d. Methylated and nonmethylated strains should be maintained among both bacteria and bacteriophages, with ratios that vary over time. e. Both A and B are correct.

In the wild, male house finches (Carpodus mexicanus) vary considerably in the amount of red pigmentation in their head and throat feathers, with colors ranging from pale yellow to bright red. These colors come from carotenoid pigments that are found in the birds' diets; no vertebrates are known to synthesize carotenoid pigments. Thus, the brighter red the male's feathers are, the more successful he has been at acquiring the red carotenoid pigment by his food-gathering efforts (all other factors being equal).

____ 18. Which of the following terms are appropriately applied to the situation described in the previous question? a. Sexual selection b. Mate choice c. Intersexual selection d. All three of these e. Only B and C

Adult male humans generally have deeper voices than do adult female humans, as the direct result of higher levels of testosterone causing growth of the larynx.

____ 19. 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. the "good genes" hypothesis was refuted by these data. d. stabilizing selection was occurring in these species concerning larynx size. e. selection was acting more directly upon genotype than upon phenotype.

____ 20. If one excludes the involvement of gender in the situation described in the paragraph above, then the pattern that is apparent in the fossil record is most similar to one that should be expected from a. pansexual selection. b. directional selection. c. disruptive selection. d. stabilizing selection. e. asexual selection.

____ 21. Which of the following statements best summarizes evolution as it is viewed today? a. It is goal-directed. b. It represents the result of selection for acquired characteristics. c. It is synonymous with the process of gene flow. d. It is the descent of humans from the present-day great apes. e. It is the differential survival and reproduction of the most-fit phenotypes. ____ 22. The average birth weight for human babies is about 3 kg. Which of the following terms best describes this? a. artificial selection b. directional selection c. stabilizing selection d. disruptive selection e. sexual selection

____ 23. Cattle breeders have improved the quality of meat over the years by which process? a. artificial selection b. directional selection c. stabilizing selection d. A and B e. A and C

____ 24. Male satin bowerbirds adorn structures that they build, called "bowers," with parrot feathers, flowers, and other bizarre ornaments in order to attract females. Females inspect the bowers and, if suitably impressed, allow males to mate with them. The evolution of this male behavior is due to a. frequency-dependent selection. b. artificial selection. c. sexual selection. d. natural selection. e. disruptive selection.

____ 25. Sparrows with average-sized wings survive severe storms better than those with longer or shorter wings, illustrating a. the bottleneck effect. b. stabilizing selection. c. frequency-dependent selection. d. neutral variation. e. disruptive selection. Chapter 23 Practice Multiple Choice Answer Section

MULTIPLE CHOICE

1. ANS: B PTS: 1 TOP: Concept 23.1 MSC: Knowledge/Comprehension 2. ANS: A PTS: 1 TOP: Concept 23.1 MSC: Knowledge/Comprehension 3. ANS: C PTS: 1 TOP: Concept 23.1 MSC: Knowledge/Comprehension 4. ANS: E PTS: 1 TOP: Concept 23.1 MSC: Knowledge/Comprehension 5. ANS: D PTS: 1 TOP: Concepts 15.4, 23.1 MSC: Synthesis/Evaluation 6. ANS: B PTS: 1 TOP: Concepts 16.2, 23.1 MSC: Synthesis/Evaluation 7. ANS: A PTS: 1 TOP: Concept 23.1 MSC: Knowledge/Comprehension 8. ANS: C PTS: 1 TOP: Concept 23.1 MSC: Knowledge/Comprehension 9. ANS: C PTS: 1 TOP: Concept 23.2 MSC: Application/Analysis 10. ANS: C PTS: 1 TOP: Concept 23.2 MSC: Application/Analysis 11. ANS: D PTS: 1 TOP: Concept 23.2 MSC: Application/Analysis 12. ANS: A PTS: 1 TOP: Concept 23.2 MSC: Application/Analysis 13. ANS: A PTS: 1 TOP: Concept 23.2 MSC: Application/Analysis 14. ANS: E PTS: 1 TOP: Concept 23.3 MSC: Knowledge/Comprehension 15. ANS: C PTS: 1 TOP: Concept 23.3 MSC: Knowledge/Comprehension 16. ANS: A PTS: 1 TOP: Concept 23.4 MSC: Application/Analysis 17. ANS: D PTS: 1 TOP: Concept 23.4 MSC: Application/Analysis 18. ANS: D PTS: 1 TOP: Concept 23.4 MSC: Knowledge/Comprehension 19. ANS: A PTS: 1 TOP: Concept 23.4 MSC: Application/Analysis 20. ANS: C PTS: 1 TOP: Concept 23.4 MSC: Application/Analysis 21. ANS: E PTS: 1 TOP: Concept 23.4 MSC: Knowledge/Comprehension 22. ANS: C PTS: 1 TOP: Concept 23.4 MSC: Knowledge/Comprehension 23. ANS: D PTS: 1 TOP: Concept 23.4 MSC: Application/Analysis 24. ANS: C PTS: 1 TOP: Concept 23.4 MSC: Application/Analysis 25. ANS: B PTS: 1 TOP: Self-Quiz Questions