Interconnected

Reading the sequence of human evolution [via Robot Wisdom] (starting 500 million years ago), I'm startled that about 2.5 million years ago the sequence split into two branches: the robust Authralopithecus (which went extinct) and the Homo Habilus line (which became modern man). And the Robust Line took over a million years to go extinct. That's a long time. What drama there must have been!