History of Life on Earth

Front

What is the geologic column?

Back

An ordered arrangement of rock layers based on relative age.

Front

What is a fossil?

Back

The remains, remnants, or traces of once-living organisms.

Front

What does Tiktaalik represent in the fossil record?

Back

A transitional fossil that shows how fish evolved into amphibians.

Front

What can the fossil record tell us about younger rock layers?

Back

Younger rock layers have both a greater variety of life and more complex organisms.

Front

What is an index fossil?

Back

A fossil that is used to define and identify a particular time period in the geologic time scale.

Front

What is absolute age in geology?

Back

The actual age of a rock or fossil, often determined through radiometric dating.

Front

What is extinction?

Back

The end of an organism or a group of organisms, leading to no living members.

Front

What is a cast fossil?

Back

A type of fossil that forms when a mold of an organism is filled with sediment or minerals.

Front

What is relative age?

Back

The age of a rock or fossil in comparison to other rocks or fossils.

Front

What is the significance of the fossil record?

Back

It provides evidence of the history of life on Earth and shows how organisms have changed over time.