Geologic Time

Front

Fossils provide evidence of __________.

Back

how life and the environmental conditions have changed over time

Front

What does the presence of limestone at the top of the Himalayas indicate about Earth's history?

Back

It shows that Earth has evolved over time as areas of land that have once been covered in water, but no longer are.

Front

Traces or remains of organisms that lived long ago are called __________.

Back

Fossil

Front

Why would a cave explorer find Megalodon shark teeth in the Arizona Desert?

Back

Millions of years ago, parts of Arizona were under water. Over time the Earth changed, the ocean became a desert, and the shark's teeth were fossilized.

Front

According to the Law of Superposition, which layer is older: Layer 7 or Layer 5?

Back

Layer 7 is older than layer 5.

Front

What is the Law of Superposition?

Back

In a sequence of undisturbed sedimentary rocks, the oldest layers are at the bottom and the youngest layers are at the top.

Front

What is a sedimentary rock?

Back

A type of rock that is formed by the accumulation and compaction of mineral and organic particles.

Front

What does the term 'geologic time' refer to?

Back

The vast time scale over which geological and biological events occur, including the formation of Earth and the evolution of life.

Front

What is an unconformity in geology?

Back

A surface of contact between two groups of unconformable strata.

Front

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

Back

Fossils help scientists understand past life forms, environments, and the changes that have occurred over time.