Ch 12: Geologic Time Scale

Front

What are epochs in the context of the geologic time scale?

Back

Epochs are subdivisions of periods in the geologic time scale, representing shorter time intervals.

Front

What is the significance of the geologic time scale?

Back

The geologic time scale outlines the history of Earth and the life forms that have existed throughout its history.

Front

What is the current status of geologic time?

Back

Geologic time is ongoing; there is no final span.

Front

What are the three eras of the Phanerozoic Eon?

Back

The three eras are Paleozoic, Mesozoic, and Cenozoic.

Front

What major periods occurred during the Mesozoic Era?

Back

The Triassic, Jurassic, and Cretaceous periods occurred during the Mesozoic Era.

Front

What was the earliest form of life on Earth?

Back

The earliest form of life was a one-celled organism.

Front

How long ago did Earth form?

Back

Earth formed approximately 4.6 billion years ago.

Front

What is the difference between an era and a period in the geologic time scale?

Back

An era is a larger time division that contains multiple periods.

Front

What is the Cenozoic Era known for?

Back

The Cenozoic Era is known for the rise of mammals and birds after the extinction of the dinosaurs.

Front

What does the term 'Paleozoic' refer to?

Back

Paleozoic refers to the era in the geologic time scale that preceded the Mesozoic Era.