geologic time

Front

What is geologic time?

Back

Geologic time is the timeline of Earth's history, divided into different intervals based on significant geological and biological events.

Front

Why is the fossil record incomplete?

Back

The fossil record is incomplete because fossils can be eroded away, most organisms never become fossils, and scavengers and decomposers can consume them too quickly.

Front

How old is Earth in years?

Back

Earth has a 4.6 billion year history.

Front

In which era are mammals the dominant group?

Back

Mammals are the dominant group in the Cenozoic era.

Front

What are index fossils?

Back

Index fossils are fossils that are distinguishable because they were widespread, very common, and lived during a short span of geologic time.

Front

What does it suggest if a fish fossil is found on top of a mountain?

Back

It suggests that a large body of water once covered that area.

Front

What are the three main eras of geologic time?

Back

The three main eras are Paleozoic, Mesozoic, and Cenozoic.

Front

What is the significance of the Cambrian explosion?

Back

The Cambrian explosion marks a period in the Paleozoic era when a rapid diversification of life forms occurred.

Front

What is relative dating in geology?

Back

Relative dating is a method used to determine the age of rocks and fossils in relation to one another, without assigning a specific numerical age.

Front

What is absolute dating?

Back

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