Lucy in the Ground with Fossils

"Researchers had previously believed that the first member of the human family tree to walk upright was Homo erectus, which flourished between 1.8 million and 70,000 years ago before giving way to modern humans. But the new discovery indicates that the transition from trees to grasslands actually took place one to 2 million years earlier."

Thomas H. Maugh II in the Los Angeles Times reports on a recent conclusion about a "fossilized foot bone from Ethiopia."