These finds include such famous East African fossils as Lucy (Australopithecus afarensis), which strengthened the importance of bipedalism in human evolution and proved an essential milestone on our way to modern Homo sapiens. (science.howstuffworks.com)
Considerable debate continues over when and in what context a modern human — like form of bipedalism evolved, because of a fragmentary record and disagreements over the functional interpretations of existing fossils and footprints. (becominghuman.org)
Researchers had previously taken bipedalism as distinctive of humans and their closest extinct relatives, together called hominins, speculating that early hominins adapted to two legs on African savannas some five million years ago, after descending from the trees and outgrowing a phase of knuckle walking similar to that of modern chimps and gorillas. (scientificamerican.com)