The Paleozoic Era lasted from approximately 538.8 million years ago to 251.9 million years ago. It is the first of three geological eras in the Phanerozoic Eon and is subdivided into six periods: Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian. The era began with the emergence of complex life and ended with a major mass extinction event known as "The Great Dying".
