Cambrian Explosion

In evolutionary theory, the cambrian explosion is the extremely rapid development of new animal phyla (body shapes) that occurred at the beginning of the Cambrian Period approximately 530 - 550 million years ago.  The duration of time in which these new phyla occurred is approximately 10 million years.1 

See the Geological Time Table

• 1. This chart was adapted from an insert called the Tower of Time by John Gurche as reproduced in The Thread of Life: The Smithsonian Looks at Evolution, by Roger Lewin, Smithsonian Books, Washington, D.C., Distributed by W.W. Norton & Company, New York, N.Y. 1982.