Geologic Time is a crucial concept to understanding the history of the earth—including the evolution of life. Many different representations of the timeline have been created, and many approaches ...

Prehistoric time line, geologic time scale, photos, facts, maps, and more from National Geographic. Humans have walked the Earth for 190,000 years, a mere blip in Earth's 4.5-billion-year history.

Time is fundamental to Earth science. Geochronology data are essential for determining the timing, duration, and rates of Earth processes and events, and are increasingly required to perform modern, ...

An Index fossil is any animal or plant preserved in the rock record of the Earth that is characteristic of a particular span of geologic time or environment. We will look at a few index fossils and ...