Geological Time Scale

Front

What is the term for the end of life for a group of organisms, usually a species?

Back

Extinction

Front

What are the divisions of periods in geological history called?

Back

Epoch

Front

What is the second broadest category of geologic time, of which the Cenozoic is one?

Back

Era

Front

How old do Paleontologists believe the Earth is?

Back

4.6 billion years old

Front

In what time period did jellyfish first appear?

Back

Precambrian Time

Front

What is the longest division of geological time?

Back

Eon

Front

What is the term for a major change in the Earth's geology or climate that can lead to extinction?

Back

Catastrophe

Front

What is the geological time scale used for?

Back

To describe the timing and relationships of events in Earth's history.

Front

What is the term for a smaller division of an era?

Back

Period

Front

What is the significance of the Law of Superposition in geology?

Back

It states that in undisturbed layers of rock, the oldest layers are at the bottom.