Geological Time

Before we talk about human evolutionary history, you need to be familiar with recent geological time periods, which provides the common vocabulary that anthropologists, geologists, and paleontologists use to discuss the sequence of evolutionary events.

Geological time goes back to the beginning of the earth, around 4 billion years ago, and is divided into eras, which are made up of multiple periods. The periods are made up of multiple epochs. To study human evolution, we're only interested in the last 8 million years or so. This is the last part of the Cenozoic Era, including the Tertiary and Quaternary Periods, and the most recent four epochs: the Holocene, Pleistocene, Pliocene, and Miocene.

Relevant Geological Time Periods

And since this is a good place to lay out general outlines of evolution, I'll add another. Here is a general schematic showing the relationship between different groups of early human ancestors, and the species that I am grouping together on the basis of generally shared adaptations. We'll be looking in great detail at this outline over the rest of the semester, but this gives you the big picture.