Geologic Time Scale

A reptile from one of two orders that dominated the mesozoic

Large, ancient landmass that was composed of all the continents joined together

The Third longest division of geologic time.

Era of recent life that began about 66 million years ago and continues today

Organisms with a three-lobed exoskeleton that was abundant in oceans and is an index fossil.

Division of earth history into time units based on lived only during certain periods.

A state of being in which one grows, reproduces, and maintains a constant internal environment.

Era of middle life, was a time of many changes on Earth.

Remains, imprints, or traces of organisms...

organisms that are suited to a particular environment

Chlorophyll-containing, photosynthetic bacteria, one of Earth’s earliest life-forms

The group of organisms that reproduces only with other members of their own group

Second-longest division of geological time.

The change organisms over geologic time.

Longest subdivision of geological time

Longest part of Earth’s history, lasting from 4.0 billion to about 544 million years ago.

The smallest division of geological time

Era of ancient life which began about 544 million years ago when organisms developed hard parts