Illinois State Museum

Tropical Forest - The Land Emerges 320 - 290 Million Years Ago

American Museum of Natural History Diorama
Pennsylvanian Forest Exhibit
Copyright, American Museum of Natural History

Broad expanses of land appeared in Illinois about 320 million years ago. Although this is not the first appearance of land, it is the first for which we have a rich record of land plants and animals. During this period, Illinois was a mosaic of seas, swamps, and dry land. Illinois was still south of the equator with a tropical climate. The emergence of large areas of land presented new challenges and opportunities for living things. Plants and animals adapted to meet these challenges and fill new niches.

When Did Life Begin on Land?
Many scientists thought that nothing lived on land until plants appeared about 420 million years ago. However, microfossils found in the 1990s indicate there were living organisms on land 1.2 billion years ago. Since then, possible evidence of microbial life has been found in Africa in 2.6 billion year old soil beds.