Ch. 23 Mastering Biology

population where accident would least likely effect the frequency of the brown allele in birds

B

variable likely to undergo the largest change in value resulting from a mutation that introduces a new allele into a population at a locus for which all individuals formerly had been fully homozygous

average heterozygosity

In the U.S., the parasite that causes malaria is not present, but African-Americans whose ancestors were from equatorial Africa are present. What should be happening to the sickle-cell allele in the United States, and what should be happening to it in equatorial Africa?

directional selection, stabilizing selection

Which of the following is most likely to produce an African butterfly species in the wild whose members have one of two strikingly different color patterns?

disruptive selection

If the original finches that had been blown over to the Galápagos from South America had already been genetically different from the parental population of South American finches, even before adapting to the Galápagos, this would have been an example of

first and third : genetic drift and founder effect

When imbalances occur in the sex ratio of sexual species that have two sexes (i.e., other than a 50:50 ratio), the members of the minority sex often receive a greater proportion of care and resources from parents than do the offspring of the majority sex. This is most clearly an example of

frequency-dependent selection

conflict between bacteria and bacteriophage at any point in time is a result of

frequency-dependent selection

If four of the original colonists died before they produced offspring, the ratios of genotypes could be quite different in the subsequent generations. This would be an example of

genetic drift

HIV particles contain two RNA molecules...If two genes from one RNA molecule become detached and then, as a unit, get attached to one end of the other RNA molecule within a single HIV particle...

one of the RNA molecules has experienced gene duplication as the result of translocation

The same gene that causes various coat patterns in wild and domesticated cats also causes the cross-eyed condition in these cats, the cross-eyed condition being slightly maladaptive. In a hypothetical environment, the coat pattern that is associated with crossed eyes is highly adaptive, with the result that both the coat pattern and the cross-eyed condition increase in a feline population over time. Which statement is supported by these observations?

phenotype is often the result of compromise