Earth's History Final "Quest"

Front

What are index fossils?

Back

Creatures that lived over a large geographic area and in a short geologic time, used to identify and date the layers of rock in which they are found.

Front

How many half-lives have occurred if a substance has decayed to one-fourth of its original amount?

Back

2 half-lives.

Front

What natural event could contribute to a mass-extinction event?

Back

A volcanic eruption.

Front

During which Era did mammals first appear?

Back

Mesozoic Era.

Front

What is the approximate age of the oldest fossils of early human ancestors?

Back

6 million years.

Front

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

Back

It is the era during which dinosaurs dominated and mammals first appeared.

Front

Define 'mass extinction'.

Back

A widespread and rapid decrease in the biodiversity on Earth, often due to catastrophic events.

Front

What is a half-life?

Back

The time required for half of the radioactive atoms in a sample to decay.

Front

What role do fossils play in understanding Earth's history?

Back

Fossils provide evidence of past life forms and help scientists understand the evolution of species and changes in the environment.

Front

What is the difference between the Paleozoic and Mesozoic Eras?

Back

The Paleozoic Era is known for the development of early life forms, while the Mesozoic Era is known for the age of dinosaurs.