Final answer:
In disruptive selection, individuals with extreme phenotypes are favored, and those with intermediate phenotypes are selected against, leading to increased genetic variance in a population. Examples include certain animal species with distinct forms of males and varying environmental conditions leading to different advantageous traits.
Step-by-step explanation:
In disruptive selection, individuals with two or more extreme fit phenotypes are selected for, while it selects against the intermediate phenotype. Unlike stabilizing selection, where phenotypes at both extremes are selected against, or directional selection, where one extreme phenotype is favored, disruptive selection increases genetic variance within a population by favoring the extremes. This can be seen in situations where environmental conditions produce different, advantageous traits at the opposite ends of the spectrum, such as in the case of the light-colored and dark-colored mice on a patchy beach environment.
Examples of Disruptive Selection
One example of disruptive selection is sexual dimorphism in certain animal species. In species with multiple male forms, for instance, both large dominant males and smaller males utilize different strategies for success. Another example involves environmental scenarios, like the mentioned mouse population on the beach, where light and dark-colored mice are favored over medium-colored mice, leading to higher survival rates for the extremes.