Exam 21: The Evolution of Populations

What is a population in biology?

If the nucleotide variability of a locus equals 0%, what is the gene variability and number of alleles at that locus?

Please use the following information to answer the question(s) below. HIV's genome of RNA includes the 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. -Which of the following represents the treatment option most likely to avoid the production of drug-resistant HIV (assuming no drug interactions or side effects)?

Please use the following information to answer the question(s) below. -Examining the figure, which type of selection eliminates extreme frequency of individuals' phenotype?

Please use the following information to answer the question(s) below. 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 10 of the original colonists had free earlobes, and 2 were heterozygous for that trait. The allele for free earlobes is dominant to the allele for attached earlobes. -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

Which of the following attributes has the least effect on the contribution an individual makes to the gene pool of the next generation?

If the original finches that had been blown over to the Galápagos Islands 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

Why don't similar genotypes always produce the same phenotype?

Anopheles mosquitoes, which carry the malaria parasite, cannot live above elevations of 5,900 feet. In addition, oxygen availability decreases with higher altitude. Consider a hypothetical human population that is adapted to life on the slopes of Mt. Kilimanjaro in Tanzania, a country in equatorial Africa. Mt. Kilimanjaro's base is about 2,600 feet above sea level and its peak is 19,341 feet above sea level. If the incidence of the sickle-cell allele in the population is plotted against altitude (feet above sea level), which of the following distributions is most likely, assuming little migration of people up or down the mountain?

Please use the following information to answer the question(s) below. In those parts of equatorial Africa where the malaria parasite is most common, the sickle-cell allele constitutes 20% of the β hemoglobin alleles in the human gene pool. -Considering the overall human population of the U.S. mainland at the time when the slave trade brought large numbers of people from equatorial Africa, what was primarily acting to change the frequency of the sickle-cell allele in the overall U.S. population?