Question

question 4 (2.5 points)
fatter sociable weaver birds spend more time foraging where they are vulnerable to predation, are more attractive to predators, and are less likely to escape an attack. conversely, thin birds risk starvation. therefore, sociable weaver of an intermediate weight have a selective advantage. this is an example of ____ selection.

frequent
directional
disruptive
stabilizing

Explanation:

Stabilizing selection favors intermediate phenotypes. In this case, intermediate - weight sociable weaver birds have an advantage. Fatter birds face predation risks (vulnerable to predation, attractive to predators, less likely to escape), and thin birds risk starvation. So, the intermediate phenotype (intermediate weight) is selected for, which is characteristic of stabilizing selection. Directional selection would favor one extreme (either very fat or very thin, but here neither extreme is favored). Disruptive selection would favor both extremes (fat and thin) over the intermediate, which is not the case here. "Frequent" is not a recognized type of natural selection in this context.

Answer:

stabilizing