Geologic Time Scale

Front

What is the purpose of the geologic time scale?

Back

To identify when events occurred in Earth's history.

Front

What is the duration of the Pleistocene Epoch?

Back

2.6 million years.

Front

What is the duration of the Mesozoic Era?

Back

180 million years.

Front

What is the significance of rock layers in dating Earth's history?

Back

They provide evidence of when rocks existed.

Front

What is the significance of major events in Earth's history?

Back

They mark divisions of time in the geologic time scale.

Front

What are the main divisions of the geologic time scale?

Back

Eons, Eras, Periods, Epochs.

Front

What is an Eon in the geologic time scale?

Back

The largest division of geologic time, lasting hundreds of millions to billions of years.

Front

What is the Phanerozoic Eon known for?

Back

It is known for the abundance of fossil evidence and the development of complex life.

Front

What major event marks the beginning of the Paleozoic Era?

Back

The Cambrian Explosion, which saw a rapid diversification of life.

Front

What is the significance of the Cretaceous-Paleogene extinction event?

Back

It marks the end of the Mesozoic Era and the extinction of the dinosaurs.