Unit 3 Earth's Biological History Test

Front

What are the subdivisions of periods in the geologic time scale?

Back

Epochs are the subdivisions of periods.

Front

What percentage of species that have ever lived are currently alive?

Back

1% of the species that have ever lived are alive today.

Front

What is a fossil that is preserved intact, including fur, hair, bones, and flesh called?

Back

An unaltered fossil.

Front

What is the term for the change in species over time as organisms adapt to their environments?

Back

Evolution.

Front

What did Earth's first atmosphere consist of?

Back

Hydrogen and Helium.

Front

What is the longest division of geologic time?

Back

Eons are the longest divisions of geologic time.

Front

What is the process by which species become extinct at a rapid rate?

Back

Mass extinction.

Front

What is the term for the preserved remains or traces of ancient organisms?

Back

Fossils.

Front

What is the significance of the Cambrian Explosion in Earth's history?

Back

It marks a period of rapid diversification of life forms.

Front

What is the geologic time scale?

Back

A system of chronological dating that relates geological strata to time.