What does disruptive selection favor in a population?

Disruptive selection favors extreme phenotypes at both ends of the phenotypic spectrum, leading to increased divergence within a population. This type of natural selection occurs when individuals with traits that are at either extreme of a trait spectrum have a fitness advantage compared to those with intermediate traits.

For example, in a population of birds where food sources are either very small or very large, birds with beak sizes at the extremes might be better adapted to efficiently exploit these resources. As a result, the population may evolve to have more individuals with either very small or very large beaks, while those with average-sized beaks may struggle to compete for food effectively.

Disruptive selection can ultimately lead to speciation, as the two extreme phenotype groups may diverge significantly over time, potentially resulting in two distinct species. This mechanism highlights the complexity of adaptations in ecosystems where diverse niches exist.