Final answer:
Disruptive selection is a type of natural selection that favors individuals with extreme variations of a trait while selecting against intermediate phenotypes, leading to increased diversity within a population.
Step-by-step explanation:
Disruptive selection is a type of natural selection that favors individuals with extreme variations of a trait. In disruptive selection, phenotypes in the middle of the phenotypic distribution are selected against. This process can result in two overlapping phenotypes at each end of the distribution, increasing the genetic variance within a population. Disruptive selection contrasts with other types of selection like stabilizing selection, which favors intermediate phenotypes, and directional selection, which favors one extreme phenotype over another.
An example of disruptive selection in nature is the difference in body size observed in certain animal populations, where both very large and very small individuals have reproductive advantages, while intermediates do not. Another example can be found in certain environments where two extreme phenotypes thrive because they blend into different aspects of the environment, while intermediate phenotypes do not and thus have a lower survival rate. Therefore, disruptive selection is a mechanism that contributes to the diversity of life and can drive speciation by favoring the survival of organisms with distinct traits that are advantageous in their specific habitats.