The Paleozoic, or "Old Life", Era is sometimes called the "Age of Fishes." It began with the Cambrian Explosion, a short period of time in which an enormous diversification of complex life occurred, and ended with the great Permian/Triassic mass extinction. It is composed of the Cambrian, Ordovician, Silurian, Devonian, Carboniferous (Mississippian and Pennsylvanian in North America), and Permian [MORE]
