Which type of natural selection encourages two extreme phenotypes over intermediate phenotypes?

Disruptive selection is a form of natural selection that favors individuals at both extremes of the phenotypic spectrum, rather than those with intermediate traits. This type of selection occurs in heterogeneous environments where individuals with extreme adaptations have a higher fitness than those with average traits. For instance, in a habitat where resources are scarce and competition is high, organisms that are either very small or very large may be more efficient at finding food or escaping predators, while those of intermediate size may struggle. As a result, the population may gradually evolve to exhibit more pronounced traits at these extremes, leading to greater variability in the traits present within that population.

Stabilizing selection, in contrast, favors intermediate phenotypes and reduces variation by selecting against extreme traits. Directional selection shifts the population trait distribution towards one extreme, rather than encouraging both extremes. Sexual selection focuses on traits that affect mating success rather than survival traits in the broader environmental context. Each of these other types of selection influences phenotypes differently, but disruptive selection specifically promotes the advantages of extremes in a population.