Wednesday, May 27, 2009

Disruptive Selection

Disruptive selection favours multiple variation or forms of a trait that differs from the current population average. It also favours individuals with variations at opposite extremes of a trait over those with intermediate variations. Environment conditions may favour more than one phenotype. Disruptive selection is a significant evolutionary mechanism used to create distinctive forms within a population. These groups of distinctive forms within the population may eventually become isolated breeding population and have separate gene pools. The following graph illustrates the effects of disruptive selection on trait distribution in a population.
Two species of flowers may be available as a food source. Only the hummingbirds that possess a certain length of bill can use the flowers as a food source.

Return to Types of Selection or proceed to Sexual Selection

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