Which type of selection leads to the production of multiple phenotypes?

Disruptive selection is a type of natural selection that promotes the existence of multiple phenotypes within a population. In this process, individuals at both extremes of a trait distribution have a selective advantage over intermediate phenotypes. As a result, the population may diverge, leading to an increase in the variety of phenotypes that are present.

For instance, consider a scenario where a particular trait, such as beak size in birds, is advantageous for both small and large seeds, while those with intermediate beak sizes are less efficient in obtaining food. This selection pressure favors the extreme phenotypes, leading to a greater diversity of traits.

In contrast, stabilizing selection works to eliminate extremes and favor intermediate phenotypes, thus reducing variation within a population. Directional selection shifts the population trait distribution toward one extreme, leading to a predominance of a single phenotype over time. Artificial selection is a process driven by human intervention to selectively breed individuals with desired traits, which can also reduce genetic diversity rather than promote it.

Therefore, disruptive selection is the mechanism that specifically enhances the presence of multiple phenotypes in a population, fostering diversity and adaptation.