We will look at a few index fossils and see if we can figure out the order they would fall on the geologic timescale. Make a timeline for each group and one for the teacher demo. I have done this with ...

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.

There are three general approaches that allow scientists to date geological materials and answer the question: "How old is this fossil?" First, the relative age of a fossil can be determined.

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 ...