What type of selection favors extreme phenotypes in a population?

Disruptive selection is a type of natural selection that favors extreme phenotypes over intermediate phenotypes within a population. This means that individuals with traits at both ends of the phenotypic spectrum have a greater reproductive success than those with average traits. As a result, disruptive selection can increase the genetic variance in a population and potentially lead to speciation, as the extremes may adapt to different niches or environmental conditions.

For example, in a population of birds that feed on seeds of varying sizes, those with either very large or very small beaks may be better suited for accessing their preferred food sources compared to individuals with medium beaks, which struggle with both sizes of seeds. Over time, this leads to the enhancement of the traits associated with the extremes, providing a clear pathway for evolutionary change.

Stabilizing selection, in contrast, works to maintain the status quo of a population by favoring average phenotypes and reducing variation, while directional selection shifts the frequency of traits in one direction, favoring one extreme phenotype. Neutral selection does not favor any particular phenotype and occurs when allele frequencies change due to random sampling, not because of selective advantages.