Unit 2 Earth History and Evolution

Front

What is radioactive dating?

Back

A method used to determine the age of rocks and fossils by measuring the decay of radioactive isotopes.

Front

What is the principle of superposition?

Back

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

Front

What is relative dating?

Back

A technique used to determine the order of events in geological history without determining their exact age.

Front

What is an index fossil?

Back

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

Front

What is extinction?

Back

The permanent loss of a species when it no longer has any living members.

Front

What factors can lead to species extinction?

Back

Environmental changes, loss of habitat, competition, and inability to adapt.

Front

What is the geologic time scale?

Back

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

Front

What are the four main geologic time periods in order from most recent to most ancient?

Back

Cenozoic, Mesozoic, Paleozoic, Precambrian.

Front

What is natural selection?

Back

The process by which organisms better adapted to their environment tend to survive and produce more offspring.

Front

How do environmental changes affect species survival?

Back

Environmental changes can create challenges that may prevent species from surviving and reproducing.