Paleozoic. The Paleozoic was a time of dramatic geological, climatic, and evolutionary change.
The Cambrian Period witnessed the most rapid and widespread diversification of life in Earth's history, known as the Cambrian explosion, in which most modern phyla first appeared. Fish, arthropods, amphibians and reptiles all evolved during the Paleozoic. Life began in the ocean but eventually transitioned onto land, and by the late Paleozoic, it was dominated by various forms of organisms. What types of animals dominated during the Paleozoic era. Happenings During the Paleozoic Era (545-248 Million Years Ago) The Palaeozoic Era. Paleozoic era - Facts from the Encyclopedia.