Which selection type commonly works against average phenotypes in a population?

Disruptive selection is a process that favors individuals at both extremes of a phenotypic spectrum while acting against the average or intermediate phenotypes in a population. This selection type can lead to increased variation within the population and can even contribute to speciation over time. In environments where resources or conditions differ greatly, individuals that possess traits at either extreme may have a better chance of survival and reproduction compared to those with traits closer to the average.

For example, in a scenario where a population of birds has varied beak sizes, birds with either very small or very large beaks might be more efficient in exploiting available food sources than those with intermediate beak sizes. Thus, through this mechanism, disruptive selection enhances the presence of extreme traits while diminishing the prevalence of average traits, thereby increasing phenotypic diversity in the population.