Ch 21 Geologic Time Review

Front

What is Geologic Time?

Back

Geologic Time refers to the vast time scale used by geologists and paleontologists to describe the timing and relationships of events in Earth's history.

Front

What is the principle of superposition?

Back

The principle of superposition states that in undisturbed sedimentary rock layers, the oldest layers are at the bottom and the youngest layers are at the top.

Front

What is relative dating?

Back

Relative dating is a method used to determine the age of rocks and fossils in relation to one another, without determining their exact age.

Front

What is absolute dating?

Back

Absolute dating is a method used to determine the exact age of a rock or fossil, often using techniques like radiometric dating.

Front

What is radiometric dating?

Back

Radiometric dating is a technique used to date materials by comparing the abundance of a radioactive isotope to its decay products.

Front

What are half-lives?

Back

Half-lives are the time required for half of the radioactive atoms in a sample to decay into a stable form.

Front

What is an isotope?

Back

Isotopes are variants of a particular chemical element that have the same number of protons but different numbers of neutrons.

Front

What is the significance of amber in fossil preservation?

Back

Amber is fossilized tree resin that can preserve soft parts of organisms, such as insects, providing valuable information about ancient life.

Front

What is a fossil?

Back

A fossil is the preserved remains or traces of a once-living organism, often found in sedimentary rock.

Front

What is a cast fossil?

Back

A cast fossil forms when a mold of an organism is filled with minerals, creating a replica of the original organism.