Brett Hilton-Barber
`I’m an expert in dating early man,” said an American woman. She looked around the conference room where hundreds of scientists were mingling amid fake rocks and designer bushman paintings, and caught the eye of her palaeontologist husband. “That’s my early man,” she smiled. “You could say we’re still dating.”
The couple were two of 700 delegates from 75 countries to converge on Sun City for the Dual Congress, a joint gathering of the International Association for the Study of Human Palaeontology and the International Association of Human Biologists.
That the congress is taking place in South Africa is significant. South Africa is in the grip of a palaeontological renaissance and a spate of new discoveries and theories has attracted international attention. The “Out of Africa” theory, for example, holds that all people descended from an “African Eve”, who lived between 75 000 and 200 000 years ago.
This point was not lost on Minister of Arts, Culture, Science and Technology Lionel Mtshali, who showed a rare glimpse of humour during the opening ceremony in welcoming the delegates back to their “ancestral home”.
The theme was picked up by congress president Professor Philip Tobias, who challenged the perception that Africa is still the “dark continent” by pointing out that the most crucial events in human history on the planet all took place on this land mass.
This can be traced all the way back to the little-known Vredefort Impact, when a huge asteroid hit the site of the Free State town two billion years ago, creating the largest crater in the world – 300km in diameter from rim to rim. The effects of this seismic collision are believed to have included the oxygenation of the earth’s atmosphere, helping emergent life forms to begin evolving.
Among Africa’s other early achievements are signs of the first mammals, the oldest hominids, the oldest example of a tool culture, the transition that led to the rise of the genus Homo, the first dramatic increases in human brain size, the first evidence of the domesticated use of fire and the emergence of Homo sapiens sapiens.
The godfather of the palaeontological mafia, Professor Tim White of the University of Berkeley, California, urged caution in adopting the “Out of Africa” theory uncritically, particularly with regard to genetic research.
White, credited with discovering the oldest hominid yet to emerge from any fossil bed anywhere (Ardipithecus ramidus in Ethiopia, dating back 4,4-million years), lashed out at molecular biologists for creating “virtual earth histories”, fanciful theories of evolution that he said were beyond the reach of palaeontological reality.
White also set the scene for the debate between the East African school of thinking and the South Africans. The so-called East Side Story, developed by French scientist Yves Coppens, holds that humans emerged from East Africa five million years ago as a result of a changing environment that saw the destruction of the Miocene forests and the opening up of the African savannah.
The Great Rift Valley has provided a comprehensive record of a number of ancestral species, including Ardipithecus ramidus, Australopithecus anamensis -discovered by Meave Leakey in 1992 and believed to be 4,2- million years old – and Australopithecus afarensis – better known as the 3,5-million- year-old Lucy, named by her discoverer, Donald Johanson, after the Beatles song Lucy in the Sky with Diamonds.
White threw down the gauntlet to the South Africans at Sun City by arguing that the East African experience suggested a unilinear development of humankind beginning with A ramidus, winding its way through A anamensis, A afarensis, into A africanus and then the early Homo species. Anyone who believed otherwise, said White, was an “X-Files palaeontologist”.
The South Africans, led by Dr Lee Berger of the University of the Witwatersrand, dispute this, saying the human family tree is far more complicated and that regional variations in evolution made a mockery of a unilinear approach.
He believes evidence is emerging in South Africa that the “speciation event” between the apemen and early humans took place south of the Limpopo and that A africanus (the hominid most often associated with South African sites) played a far more central role in the development of Homo than the East Africans are comfortable with.
He says a speciation event could well have taken place between 2,8-million and 2,6- million years ago. This would have seen some A africanus populations taking on the physical characteristics of early Homo on the one hand, and others evolving towards the more robust australopithecine form on the other. The counter-argument is that Homo emerged from the gracile australopithecines of East Africa, A afarensis, and then migrated southwards.
The East Africans have attacked the South Africans on another front. Dr Bruce Latimer, of the Cleveland Natural History Museum, has challenged the assumptions made by Tobias and Dr Ron Clarke over “Little Foot”, which the two presented to the world in July 1995.
“Little Foot” is the name given to the four little left-foot bones thought to belong to an adult A africanus from about 3,5-million years ago.
The South Africans argued that the skeletal structure clearly showed the transition from ape to human, as the big toe was prehensile, or monkey-like in its ability to grip.
Latimer disputes this, saying that there is nothing about Little Foot that is prehensile. “It is clearly human,” he says, but adds little to what has already been known for decades, that it cannot be held up as an example of speciation.
One thing that has become clear about palaeontological research is that there is very rarely a last word. New discoveries and new techniques of dating and analysing necessitate an open approach to exploring humanity’s deep past.
What isn’t in dispute is South Africa’s importance as a fossil archive. This country has contributed about 40% of the total fossil hominids found so far in Africa, and with funding for exploration and research having been secured from the National Geographic Society and the Palaeo-anthropological Scientific Trust, a new era of discovery is about to begin.