CK-12 Foundation
Ck 12: Episd: Natural Selection
[Free Registration/Login may be required to access all resource tools.] Understand what natural selection is and how it works and explain how new species originate.
CK-12 Foundation
Ck 12: Biology: Natural Selection
[Free Registration/Login may be required to access all resource tools.] Describes how natural selection changes allele frequency.
BiologyWise
Biology Wise: Definition and Examples of Stabilizing Selection
Explains what stabilizing selection is and how this type of natural selection actually limits genetic diversity in a population. Presents examples of stabilizing selection in different plants and animals.