Geologic Time Scale

Front

What is the Geologic Time Scale?

Back

A system of chronological dating that relates geological strata to time, used to describe the timing and relationships of events in Earth's history.

Front

What is the largest mass extinction in Earth's history?

Back

The Permian Extinction, where approximately 96% of all species on Earth disappeared.

Front

In which mass extinction did the dinosaurs go extinct?

Back

The Cretaceous-Tertiary (K-Pg) Mass Extinction.

Front

During which time segment of the Geologic Time Scale did life first appear?

Back

Precambrian Time.

Front

What is the largest unit of geologic time?

Back

Era.

Front

How many mass extinctions have occurred in Earth's history?

Back

Five mass extinctions.

Front

Which mass extinction occurred first?

Back

End Ordovician.

Front

What is the significance of the Paleozoic Era?

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It is known for the emergence of diverse marine life and the first land plants.

Front

What major event marks the end of the Mesozoic Era?

Back

The Cretaceous-Tertiary (K-Pg) Mass Extinction.

Front

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

Back

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