Mechanisms of Evolution Foldable page 9

Distribution Curves: Normal Distribution The animals with the mean or average variation is selected for, the animals with extreme variations are at a disadvantage. There are more average animals than extreme. Mean/ Average Extreme

Distribution Curves: Directional Selection Animals with one side of the extreme have a better advantage, so the curve shifts.

Distribution Curves: Stabilizing Selection Animals with the average variation surge in population number, while animals with the extreme variation decrease rapidly.

Distribution Curves: Disruptive Selection Animals with both extremes (both sides of the bell) are favored, and animals with the average variation die off.