Paleozoic Era Environment
The environment during the Cambrian time period was mostly marine environment. That changed in the Ordovician period because then it turned in a tropical environment. During the Silurian period, the sea levels rose and there were coral reefs and freshwater. In the Devonian period, forests grew. During the Carboniferous period, the environment was moist and swampy. In the Permian period, it was a marine environment.