updated human timeline

The timeline of human evolution just got more complicated, as it does every few years or so.

The old theory was that the first and oldest species in our family tree, Homo habilis, evolved into Homo erectus, which then became us, Homo sapiens. But those two earlier species lived side-by-side about 1.5 million years ago in parts of Kenya for at least half a million years, Leakey and colleagues report in a paper published in Thursday's journal Nature.

Leakey's co-author notes that human evolution is a

"chaotic kind of looking evolutionary tree rather than this heroic march that you see with the cartoons of an early ancestor evolving into some intermediate and eventually unto us."

That's the point I'd want students to get out of this article. It's not a straight line, its many branches and dead ends.