Stabilizing selection

Fig Human birth weight, an example of stabilizing selection

Directional selection

Fig An example of directional selection. Guppies become more colorful (blue and yellow lines on graph) in the absence of predation, and less colorful (red graph line) when in the presence of predation.

D.disruptive selection 1.both extreme phenotypes are adaptive and selected for 2.two “averages” are formed Disruptive selection

Fig Three different kinds of selection: (a) stabilizing, (b) directional, and (c) disruptive

Another real example of the three different kinds of selection

An example of genetic drift

Fig Genetic drift

Schematic view of a population bottleneck

Schematic view of founder effect