At the beginning of the Paleozoic era there was a big boom in animal life on planet earth, and in the end there was a mass extinction wiping out 90% of major animals. The first period in the Paleozoic era, the Cambrian period, was the time when most major animals appeared on earth. By the next period, the Ordovician period, organisms could now live on land and now just water. During the Silurian Period, the earth went through a lot of changes, such as glaciers melting. During The Devonian period, the first land living vertebras, tetrapod, and terrestrial arthropods appeared on the earth’s surface. During the Carboniferous period, the birds evolved to lay eggs so they could explore further inland. During the Permian period, the largest mass
