Geological and Biological Concepts

Front

Cambrian explosion

Back

A time of rapid expansion of different forms of life on earth; when most of the major animal groups started to appear in the fossil record.

Front

Cenozoic

Back

Recent life; age of mammals.

Front

Cyanobacteria

Back

An ancient group of photosynthetic microbes that occur in most inland waters and that can have major effects on the water quality and functioning of aquatic ecosystems.

Front

Endosymbiosis

Back

Two organisms living together with one inside the other.

Front

Epoch

Back

Unit of geological time during which a rock series is deposited.

Front

Era

Back

A very long span of geologic time; in formal usage, the second longest portions of geological time.

Front

Geological time scale

Back

Timeline used to represent earth’s history.

Front

Half life

Back

Length of time required for half of the radioactive atoms in a sample to decay.

Front

Index fossil

Back

Any animal or plant preserved in the rock record of the Earth that is characteristic of a particular span of geologic time or environment.

Front

Isotope

Back

Atoms of the same element with a different number of neutrons.