Question

which of the following is an example of nonadaptive evolution? select the two answers that are correct.
□ the percentage of dark - colored moths in a population increases over time as pollution darkens tree bark.
□ the allele for sickle cell anemia is more prevalent in populations of african descent because it provides resistance to infection from malaria, a parasite common in africa.
□ two populations of finches in the galapagos islands have different beak lengths, each suited to the food available within its ecological niche.
□ a mutation causes an increase in the incidence of antibiotic sensitivity in a population of staphylococcus aureus.
□ the gene pool of a drastically reduced population of northern elephant seals is vulnerable to chance events.

Explanation:

Nonadaptive evolution refers to changes in allele frequencies not driven by natural selection (no fitness advantage). Option D: A mutation increasing antibiotic sensitivity does not provide a fitness benefit (antibiotic-sensitive bacteria are less fit in environments with antibiotics), so it is nonadaptive. Option E: A drastically reduced population (bottleneck effect) leads to genetic drift, a random process (chance events) not driven by adaptation, so it is nonadaptive. The other options involve natural selection (adaptive evolution): dark moths (camouflage), sickle cell allele (malaria resistance), finch beaks (food adaptation).

Answer:

D. A mutation causes an increase in the incidence of antibiotic sensitivity in a population of Staphylococcus aureus., E. The gene pool of a drastically reduced population of northern elephant seals is vulnerable to chance events.