Question

a population of pigs lives on an island together with burrowing termites. pigs that have the longest snouts tend to survive more frequently than those with shorter snouts. over time, most of the pig population is made up of individuals that have very long snouts. this is an example of which type of selection?
○ directional selection
○ disruptive selection
○ stabilizing selection
○ ecosystem selection

Explanation:

To determine the type of selection, we analyze each option:

• Directional selection: Favors one extreme phenotype (here, the longest snouts) and shifts the population's trait distribution in that direction. This matches the scenario where long - snouted pigs survive more and become the majority.
• Disruptive selection: Favors two or more extreme phenotypes and selects against the intermediate ones. There's no indication of two extreme phenotypes being favored here.
• Stabilizing selection: Favors the intermediate phenotype and selects against the extremes. But in this case, the extreme (long snouts) is favored, so this is not correct.
• Ecosystem selection is not a recognized type of natural selection.

Answer:

A. directional selection