RedOrbit: In the past, scientists concluded many of mans defining qualities, such as legs made for walking upright and a large brain, evolved all at once. But according to a new study in the journal Science, shifts in climate caused these qualities to evolve separately.
Based on analyses of fossil evidence, the study researchers said the shrinking of forests and expansion of savannas in East Africa led to walking upright, which freed our forebears hands up for the creation and use of stone tools.
"Unstable...