Evolution, the unifying theory of biology, describes a mechanism for the change and diversification of species over time.
Charles Darwin and Natural Selection
Charles Darwin and Alfred Wallace independently developed the theories of evolution and its main operating principle: natural selection.
Visible evidence of ongoing evolution: Darwin
The differences in shape and size of beaks in Darwin's finches illustrate ongoing evolutionary change.
Processes and Patterns of Evolution
Natural selection can only occur in the presence of genetic variation; environmental conditions determine which traits are selected.
Evidence of Evolution
Evidence for evolution has been obtained through fossil records, embryology, geography, and molecular biology.
Misconceptions of Evolution
There are many misconceptions about evolution, including the meaning of the word theory, the way populations change, and the origin of life.