When did bipedalism evolve? Where did it evolve?

Question

When did bipedalism evolve? Where did it evolve?

Answer 1

The answer is not Sahelanthropus tchadensis  

This species was named in July 2002 from fossils discovered in Chad in Central Africa (Brunet et al. 2002, Wood 2002). It is the oldest known hominid or near-hominid species, dated at between 6 and 7 million years old. This species is known from a nearly complete cranium nicknamed Toumai, and a number of fragmentary lower jaws and teeth. The skull has a very small brain size of approximately 350 cc. It is not known whether it was bipedal. S. tchadensis has many primitive apelike features, such as the small brainsize, along with others, such as the brow ridges and small canine teeth, which are characteristic of later hominids. This mixture, along with the fact that it comes from around the time when the hominids are thought to have diverged from chimpanzees, suggests it is close to the common ancestor of humans and chimpanzees.

With current knowledge it appears that the answer is as follows.

In 2006, Tim White of the University of California, Berkeley, announced the discovery of bones from at least 8 Australopithecus anamensis individuals dating to 4.1 million years ago in what had been a woodland environment in the Awash Valley of Ethiopia.  White believes that anatomically they are direct descendents of Ardipithecus ramidus and direct ancestors of Australopithecus afarensis.  In other words, he asserts that there was a single evolutionary line of the earliest hominids without branching out into other species and that this evolutionary development occurred in East Africa in an area that included at least the Great Rift Valley in Kenya and Ethiopia.

Answer 2

Evolve is one of two-sided coin,  Faith being the other.  Personally,  I prefer not believing in the slug theory.  After all,  Primates are still Primates.  Thank Heaven, it wasn't our future !!

Answer 3

The creature Toumai (Sahelanthropus tchadensis) lived maybe 6 million years ago and shows evidence of bipedalism and is a probably human ancestor.  Orrorin lived 5 million years ago and has femur that shows strong evidence of bipedalism.  Since the split between humans and chimps was around this time, it is my opinion that the chimp human common ancestor was likely bipedal.  This means that chimps may have evolved knucklewalking separately from gorillas.  This begs the question, "did gorillas also similarly evolve their knucklewalking from a biped?"  We don't have fossil evidence and it kind of my pet theory though so obvious I can hardly take credit for it.  Since gorillas chimp human common ancestor is believed to be 7 to 8 million years, it can be speculated that bipedalism (in a human ancestor) is 8 to 9 million years old.  Most paleontologists probably wouldn't speculate past 5 million years and assume the chimp ancestor was a knucklewalker.