Cambrian (541-485 million years ago)

Complex, multicellular animal life appeared during the Cambrian Explosion. All the major groups of animals, plus some that are now extinct, were found in the ocean.

Ordovician (485-444 million years ago)

The number of species tripled and the sea teemed with life. Animals moved into many new habitats, and trilobites and cephalopods abounded.

Silurian (444-419 million years ago)

Life thrived in the ocean. Fish developed jaws, giant sea scorpions ruled the shallows, and animals began to colonize the land.

Devonian (419-359 million years ago)

Known as the Age of Fishes. Fish grew to enormous sizes, and some even crawled out of the water. The first forests and seed-bearing plants grew on land.

Carboniferous (359-299 million years ago)

Known as the Age of Amphibians. Forests and swamps took over the landscape, creating the coal beds we use today for fuel. Reptiles, amphibians, and giant insects roamed the land.

Permian (299-252 million years ago)

Giant reptiles, including the ancestors of dinosaurs and mammals, reigned supreme. The Permian ended with the Great Dying, the largest mass extinction in Earth history.