Radiometric dating technique used to date lucy
Many held that Australopithecus afarensis was not a discrete species, and still others—most notably the Kenyan paleoanthropologist Richard Leakey—balked at the assertion that fossils like Lucy were the direct ancestors of modern humans.
The case for Australopithecus afarensis was strengthened in the early 1990s, however, when further research at Hadar yielded a wealth of other Lucy-like fossils including near-complete skulls of both male and female specimens.
She would have appeared more ape-like than human, with long arms and a protruding belly.
Unlike knuckle-dragging apes, however, the structure of her bones showed that she walked upright on two legs.
They called them “Australopithecus afarensis,” after the Afar Triangle in which Lucy was found.
“You just don’t expect to find this much of a single individual.” Johanson and Gray raced to tell their colleagues. ” That night, the jubilant field team celebrated the discovery over dinner and several cans of beer.But when he took a closer look, he saw that many of her features were significantly more primitive than other Australopithecine specimens. The duo compared Lucy to a so-called “First Family” of some 13 other skeletal remains found at Hadar as well as to a collection of hominid footprints excavated by famed anthropologist Mary Leakey in Laetoli, Tanzania.Finally, in 1978, they released a groundbreaking paper classifying Lucy, the other Hadar fossils and the Laetoli footprints as all belonging to a brand new species of early hominid human ancestors.She was surprisingly small—slightly less than 4 feet tall—and would have tipped the scales at roughly 60 pounds.Her larger pelvic opening suggested she was female, and wear on her wisdom teeth hinted she was probably around 20 years old when she died (more recent estimates suggest she may have been closer to 12 or 13).
The headline-grabbing find filled in crucial gaps in the human family tree, but it also shook up ideas about early human evolution and upright walking.