Geological Time Scale

Front

What is the importance of studying fossils?

Back

Studying fossils provides information about how life and environmental conditions may have changed over time.

Front

What event marks the first appearance of most major groups of animals in the fossil record?

Back

The Great Cambrian Explosion.

Front

What is the chronological time chart that breaks down geological time into Eons, Eras, Periods, and Epochs called?

Back

Geological time scale.

Front

What are specialized fossils that indicate boundaries in geological time and help determine the age of rocks?

Back

Index fossils.

Front

Which fossil is considered the youngest?

Back

Fossil C.

Front

What is an Eon in the geological time scale?

Back

An Eon is the largest division of geological time, encompassing billions of years.

Front

What is an Era in the geological time scale?

Back

An Era is a subdivision of an Eon, lasting tens to hundreds of millions of years.

Front

What is a Period in the geological time scale?

Back

A Period is a subdivision of an Era, lasting millions of years.

Front

What is an Epoch in the geological time scale?

Back

An Epoch is a subdivision of a Period, lasting several million years.

Front

What does the Law of Superposition state?

Back

In undisturbed layers of rock, the oldest layers are at the bottom and the youngest are at the top.