Fossils show that fish eventually evolved into amphibians, who live in both land and water. But what was the reason for going on land? Some scientists think that droughts occurred, forcing fish on land. Fish, in turn, adapted to this new life. These fishes could also have been escaping from larger predators. It was during the Devonian and Carboniferous Periods that amphibians actually evolved. The first known amphibian is called Ichthyostega. Ichthyostega was in the Labyrinthodont group, and was about three feet long. Later on in the Paleozoic, Amphibians evolved into repiles. The reptiles, it seems, forced the amphibians off of the land and back to the water by the Permian Period.

Labyrinthodonts, an early type of amphibian.

Some of earliest land animals were amphibians

Paleozoic Era: Creature Feature