Biology (B)

Vocabulary

Cambrian explosion

A sudden burst of evolution that may have been triggered by some environmental changes that made the environment more suitable for a wider variety of life forms.

extinct

Something that does not exist anymore; a group of organisms that has died out without leaving any living representatives.

mass extinction

An extinction when many species go extinct during a relatively short period of time.

radiometric dating

A method to determine the age of rocks and fossils in each layer of rock; measures the decay rate of radioactive materials in each rock layer.

stromolites

Fossils made of algae and a kind of bacteria; some of the oldest fossils on Earth.