Question

In some instances environmental change causes a situation where one phenotype is favored for a period of time, and then a different phenotype is favored. This oscillating selection causes?

1) extinction of the population
2) elimination of rarer genotypes because of uneven selection
3) an increase in point mutations
4) high population increase to maintain phenotypic variation
5) the maintenance of genetic variation in the population

Answer 1

Oscillating selection due to environmental changes maintains genetic variation within a population by favoring different phenotypes at different times.

Step-by-step explanation:

In cases where environmental change causes one phenotype to be favored for a while before a different phenotype is favored, this oscillating selection leads to maintenance of genetic variation in the population. This pattern is different from stabilizing selection, which favors average phenotypes, or directional selection, which occurs when environmental changes create a shift in the population's variance toward a new, advantageous phenotype. The oscillation allows for multiple phenotypes to offer a reproductive advantage at different times, preventing any single phenotype from becoming fixed within the population and thus maintaining a broader range of genetic diversity.