Geologic Time Scale

Front

Preserved remains of plants and animals from the remote past are called __________.

Back

fossils

Front

Approximately how old is Earth?

Back

4.6 billion years

Front

The end of life for a group of organisms, usually a species, is called a ___________.

Back

mass extinction

Front

Jellyfish are one of the oldest species on Earth. In what time period did they first appear?

Back

Precambrian

Front

What does 'relative age' tell about rock layers or fossils?

Back

the age of one rock layer or fossil compared to another

Front

What is the Geologic Time Scale?

Back

A system that organizes Earth's history into different time intervals based on significant geological and biological events.

Front

What are the four main eons of Earth's history?

Back

Hadean, Archean, Proterozoic, Phanerozoic

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 a mass extinction event?

Back

A period in which a large number of species go extinct in a relatively short time.

Front

What is the significance of fossils in understanding Earth's history?

Back

Fossils provide evidence of past life and help scientists understand the evolution of species.