A Timescale is a scale used to represent periods of time. Option: Have students make a ... Explain that scientists also like to sort events in the order they have happened. Show the geologic timeline.

The evolution of the human mind has allowed us to transcend our modern understandings of time and expand into the realm of ...

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.

The geologic time scale is divided into eons ... such as the transition from Jurassic to Cretaceous 145.5 million years ago. The largest extinction events define a change in era. The end of the ...