Free Republic

A blackened, broken leg bone from Earth’s prehistoric past may hold the answer to when early humans diverged from apes and started their own evolutionary path.The fossilized find, first uncovered two decades ago, suggests that early humans regularly walked on two feet some seven million years ago... Since many consider bipedalism the major milestone that put our own lineage on a different evolutionary path than the apes, Sahelanthropus could be the very oldest known hominin—the group consisting of modern humans, extinct human species and all of our immediate ancestors.The species could even be our oldest non-ape ancestor, if its lineage...

An upright gait and a relatively sophisticated ability to manipulate objects apparently evolved in tandem among the earliest hominids at least 6 million years ago, said Sergio Almécija of the Autonomous University of Barcelona. That's well before the earliest evidence of stone toolmaking, about 2.6 million years ago, arguing against the idea that fine motor skills for toolmaking drove the evolution of opposable thumbs. Almécija and his colleagues studied a bone from the tip of a thumb belonging to Orrorin tugenensis. At an estimated 6 million years old, Orrorin is the second oldest hominid genus. A more recently identified...