Natural selection is of three types directional, stabilizing, and disruptive selection.
1. Directional selection occurs when natural selection favors one extreme of continuous variation. Over time, the favored extreme will become more common and the other extreme will be less common or lost.
3. Stabilizing selection occurs when natural selection favors the intermediate states of continuous variation. Over time, the intermediate states become more common and each extreme variation will become less common or lost.
4. Disruptive selection occurs when natural selection favors both extremes of continuous variation. Over time, the two extreme variations will become more common and the intermediate states will be less common or lost. Disruptive selection can lead to two new species.