Paleozoic Era Major Events
There were many major events of the Paleozoic Era. During the Cambrian period hard-shelled mollusks and the earliest vertebrates appeared. During the Ordovician period, the earliest cartilaginous fish inhabited the land. During the Silurian period, spiders and scorpions that originated in the water and started to live on land. Plants start to live on the land and not in the water. During the Devonian period, amphibians started to live on the land. During the Carboniferous period, a single supercontinent combined, coal-forming swamp forests survived, and the earliest reptiles appear. During the Permian period, therapsids became the dominant land animal toward the end of the Permian period and Earth had the largest extinction ever. The extinction wiped out about 95% of marine species and 70% of land animals. Scientists think that climate change caused the extinction.