National Institutes of Health
National Center for Biotechnology Information: Phylogenetics Factsheet
A detailed website that explains the history and process of classifying animals using evolutionary, molecular, and physical characteristics relationships. Website also contains information on evolution and evolutionary processes....
CK-12 Foundation
Ck 12: Biology: Forces of Evolution
[Free Registration/Login may be required to access all resource tools.] Describes three of the four forces of evolution: mutation, gene flow, and genetic drift.