Biological evolution is any genetic change in a population that is inherited over several generations. These changes may be small or large, noticeable or not so noticeable. The theory of evolution explains how all of life's diversity and various species evolved from a single common ancestor that existed about 3.7 billion years ago.
 
eye evolution
How evolution works
human evolution
Evidence for evolution
human evolution
Q&A and misconceptions
 
eye evolution
Evolution of the eye
human evolution
Human evolution
 

Truth-Saves