What type of selection may lead to two or more contrasting phenotypes in a population?

Disruptive selection is a mode of natural selection that favors individuals at both extremes of the phenotypic spectrum, rather than individuals with average traits. This can lead to the emergence of two or more contrasting phenotypes in a population. For example, in a case where a species has individuals that are either very light or very dark, disruptive selection would enhance traits that lead to these extremes while selecting against the intermediate coloration. This can ultimately result in the divergence of the population into distinct forms that are better adapted to different ecological niches.

In contrast, directional selection shifts the population toward one extreme phenotype, favoring individuals at one end of the distribution. Stabilizing selection favors intermediate phenotypes and reduces variation, leading to an overall decrease in phenotypic diversity rather than the establishment of distinct contrasting types. Sexual selection, while it can influence reproductive traits, typically does not create multiple distinct phenotypes in the same way that disruptive selection does. Thus, disruptive selection is the mechanism most directly associated with the development of contrasting phenotypes within a population.