Question

The three types of natural selection are

A. directional selection, artificial selection, and disruptive selection.
B. directional selection, artificial selection, and normalizing selection.
C. disruptive selection, stabilizing selection, and normalizing selection.
D. disruptive selection, stabilizing selection, and artificial selection.
E. directional selection, disruptive selection, and stabilizing selection.

Answer 1

The three types of natural selection are directional selection, disruptive selection, and stabilizing selection. Directional selection occurs when one extreme phenotype is selected for, disruptive selection occurs when phenotypes in the middle of the range are selected against, and stabilizing selection occurs when phenotypes at both extremes are selected against.

Step-by-step explanation:

The three types of natural selection are directional selection, disruptive selection, and stabilizing selection.

Directional selection occurs when one extreme phenotype is selected for, shifting the distribution toward that extreme. Disruptive selection occurs when phenotypes in the middle of the range are selected against, resulting in two overlapping phenotypes at each end of the distribution. Stabilizing selection occurs when phenotypes at both extremes are selected against, narrowing the range of variation.

For example, the beak size of Galápagos finches underwent directional selection, while sexual dimorphism in humans is an example of disruptive selection.