The Paleozoic Era is a major division of Earth's geological history, lasting from about 541 to 252 million years ago. It is characterized by the emergence of diverse life forms, including the first fish, amphibians, and reptiles. This era is divided into six periods: Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian. During the Paleozoic, the continents were arranged differently than today, and life flourished in both marine and terrestrial environments. The era ended with the largest mass extinction in Earth's history, known as the Permian-Triassic extinction, which wiped out approximately 90% of species.