Geologic Time Assessment

Front

What is Half-life?

Back

The amount of time it takes for half the nuclei in a sample of the isotope to decay.

Front

Which layer is the youngest?

Back

Layer Z.

Front

What can be learned by using the fossil record?

Back

All the above: when organisms changed or evolved, when organisms appeared on Earth, when organisms became extinct.

Front

What are the remains, imprints, or traces of once-living organisms?

Back

Fossil.

Front

What does the law of superposition state?

Back

The oldest rock layers are formed earliest and found at the bottom of a geologic column.

Front

What is a fossil?

Back

The remains or traces of once-living organisms preserved in rock.

Front

What is the geologic time scale?

Back

A system of chronological dating that relates geological strata to time.

Front

What is an index fossil?

Back

A fossil that is used to define and identify a particular time period.

Front

What is radiometric dating?

Back

A method used to date materials by comparing the abundance of a radioactive isotope to its decay products.

Front

What is the principle of original horizontality?

Back

Layers of sediment are originally deposited horizontally under the action of gravity.