Dating relationship origins
Broom planted the South African fossils firmly on the scientific map in a 1946 study, concluding that these ancestors were “nearly men, and were certainly closely allied to mankind.” At the time of Broom’s study, Louis Leakey, the Kenyan-born son of English missionaries, was struggling to vindicate his long-held belief that humanity was in fact rooted in his native East Africa.His quest finally bore fruit in 1959, when he and his wife, Mary, discovered an australopithecine skull in Tanzania’s Olduvai Gorge.At two million years, they are not as old as the earliest known fossil of the genus Homo in East Africa—a 2.8 million-year-old jaw found recently at a site called Ledi-Geraru in Ethiopia. sediba stands as the best candidate for the most recent ancestor of our genus—we just haven’t yet found other, earlier fossils of its kind that predate the Ledi-Geraru jaw.
They dubbed it Homo habilis, or “handy man,” after a scatter of stone tools close by.
Being able to date fossils enabled researchers to know how old they were in relationship to each other, connecting the discoveries emerging from the East African Rift into a phylogeny—a human family tree. Along with some other species with robust skulls and teeth and gorilla-like crests on their craniums, it was assigned to an extinct side branch of the family tree.
Johanson and his collaborator Tim White assigned the Lucy skeleton and some other fossils to a new species, Australopithecus afarensis, dated to 3.2 million years ago. afarensis was the ancestor to Homo habilis, at a little under two million years old the most primitive member of our genus. habilis evolved into the younger, more advanced species Homo erectus, which in turn evolved into us. Firmly planted in East Africa, that version of the family tree cast a shadow over South Africa.
In 1924, anatomist Raymond Dart found a skull of a juvenile primate among a box of fossil-bearing rocks sent to him by the manager of a quarry at Taung, on the edge of the Kalahari Desert.
Despite a tiny brain and other apelike features, the position of the opening at the base of the skull convinced Dart that the “Taung child” had walked upright like a human.