Ch 12: Geologic Time Scale

Front

What is the earliest form of life on Earth?

Back

A one-celled organism.

Front

What era is known as the era of recent life?

Back

Cenozoic.

Front

How many million years ago did the dinosaurs die out?

Back

65 million years ago.

Front

List the three Eras in the Phanerozoic Eon in the correct order.

Back

Paleozoic, Mesozoic, Cenozoic.

Front

True or False: Geologists subdivide periods into eras.

Back

False.

Front

What are the four main divisions of the Geologic Time Scale?

Back

Eons, Eras, Periods, and Epochs.

Front

What is the significance of the Cenozoic Era in Earth's history?

Back

It is known as the era of recent life, characterized by the dominance of mammals and birds.

Front

What major event marks the end of the Mesozoic Era?

Back

The mass extinction event that led to the demise of the dinosaurs.

Front

What is the difference between an Era and a Period in the Geologic Time Scale?

Back

An Era is a larger division of time that encompasses multiple Periods.

Front

What is the Phanerozoic Eon known for?

Back

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