Eras of Earth's History

Front

Age of Earth

Back

About 4.5 billion years

Front

Precambrian Era

Back

Earth's formation to 541 million years ago

Front

Paleozoic Era

Back

541 to 252 million years ago

Front

Mesozoic Era

Back

252 to 66 million years ago

Front

Cenozoic Era

Back

66 million years ago to present

Front

Comet

Back

An icy body in space, often with a tail.

Front

Continental Drift

Back

Movement of Earth's continents over time

Front

Invertebrate

Back

An animal without a backbone

Front

Vertebrate

Back

An animal with a backbone.

Front

First Amphibians

Back

Appeared in the Paleozoic Era