Out of Africa: The Sequel
McKie (Robin)
Source: Guardian Weekly, 05/03/2010 (originally from the Observer)
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Notes

  1. From Guardian Weekly, 5th March 2010 (extracted from the Observer).
  2. Forwarded by Mike Penny with the comment "Please find enclosed an article from the weekly Guardian. Sylvia has done all the markings and we were discussing this. It shows the absolute uncertainty of the absoluteness of evolutionary1 science. No other scientific theory would be allowed to get away with so many caveats and still hold it head up high. "
  3. Naturally, I reject these thoughts!
  4. See also "Burkeman (Oliver) - Revolution in Evolution" and "Krause (Johannes) - Our Ancestral Cave Gets More Crowded".

Full Text

Tiny hominids found on an Indonesian island, and not Homo erectus, were the first to colonise other parts of the world, reports Robin McKie.
  1. It remains one of the greatest human fossil discoveries of all time. The bones of a race2 of tiny primitive people, who used stone tools to hunt pony-sized elephants and battle huge Komodo dragons, were discovered on the Indonesian island of Flores in 2004.
  2. The team of Australian researchers had been working in a vast limestone cavern, called Liang Bua, in one of the island's remotest areas, when one scientist ran his trowel against apiece of bone. Carefully the group began scraping away the brown clay in which pieces of a tiny skull and a little lower jaw, were embedded.
  3. This was not any old skull, they quickly realised. Although small, it had special characteristics. In particular, it had adult teeth. "This was no child, but a tiny adult: in fact, one of the smallest adult hominids ever found in the fossil record," says Mike Morwood, of Australia's University of Wollongong and a leader of the original Flores expedition team.
  4. These remains came from a species that turned out to be only a metre tall and had a brain the size of an orange. Yet it used quite sophisticated stone tools. How on earth could such individuals have made complex implements and survived for aeons - on this remote part of the Malay archipelago?
  5. Some simply dismissed the bones as the remains of deformed modern humans with diseases that had caused them to shrink. Most researchers disagreed, however. The so-called hobbits were the descendants of a race3 of far larger ancient humans who had thrived around 1m years ago. These people, known as Homo erectus, had become stranded on the island and then had shrunk in an evolutionary4 response to the island's limited resources.
  6. That is odd enough. However new evidence suggests the little folk of Flores may be even stranger in origin. According to a growing number of scientists, Homo floresiensis is probably a direct descendant of some of the first apemen to evolve on the African savannah 3m years ago. These primitive hominids somehow travelled half a world from their probable birthplace in the Rift Valley before eventually reaching Flores.
  7. It sounds unlikely, but the physical similarity between the two species is striking. Consider Lucy, the 3.2m-year-old member of Australopithecus afarensis. She had a very small brain, primitive wrists, feet and teeth and was only one metre tall, but was still declared "the grandmother of humanity" after her discovery in Ethiopia in 1974. Crucially, analysis of Lucy’s skeleton shows it has great similarities with the bones of H floresiensis, although her species died out millions of years ago while the hobbit hung on in Flores until about 17,000 years ago. This latter figure is staggeringly close in terms of recent human evolution5 and indicates that long after the Neanderthals, our closest evolutionary6 relatives, had disappeared from the face of the Earth around 35,000 years ago, these tiny, distant relatives of Homo sapiens were still living on remote Flores. The crucial point about this interpretation is that it explains why the Flores people had such minuscule proportions. They didn’t shrink but were small from the start - because they came from a very ancient lineage of little apemen. They acquired no diseased deformities, nor did they evolve a smaller stature over time. They were, in essence, an anthropological relic and Flores was an evolutionary7 time capsule. In research that provides further support for this idea, scientists have recently dated some stone tools on Flores as being around 1.1m years old, far older than had been previously supposed.
  8. “The possibility that a very primitive member of the genus Homo left Africa roughly 2m years ago, and that a descendant population persisted until only several thousand years ago is one of the more provocative hypotheses to have emerged in anthropology during the past few years," David Strait of the University of Albany told Scientific American recently. This view is backed by Professor Chris Stringer of the Natural History Museum, London. "We are still grappling with what this discovery has done for our thinking and our conventional scenarios."
  9. In addition, Morwood says he has now uncovered stone tools on nearby Sulawesi. These could be almost 2m years old, he believes, which suggests the whole region was populated by very ancient hurmans for a startlingly long part of human prehistory. "This is going to put the cat among the pigeons," Norwood says.
  10. However, it is the hobbits' similarity to ancient African apemen that provides the most compelling evidence for their ancient origins. In the Journal of Human Evolution8, a team led by Debbie Argue of the Australian National University recently reported that analysis of H floresiensis shows they most closely resemble apelike human ancestors that first appeared around 2.3m years ago in Africa. In other words, their stock maybe not quite as old as Lucy's but probably comes from a hominid, known as Homo habilis, that appeared on the evolutionary9 scene not long after Lucy's species disappeared. Homo habilis's features now seem to match, most closely, those of H foresiensis.
  11. Consider those hobbit feet, for example. The skeleton unearthed on Flores had a foot that was 20cm in length. This produces a ratio of 70% when compared with the length of the hobbit's thigh bone. By contrast, men and women today have foot-to-thigh bone ratios of 55%. The little folk of Flores had singularly short legs and long, flapper feet, very similar to those of African apemen, even though limbs like these would have made their long march from Africa to Flores a painful business.
  12. Similarly, the hands of H floresiensis were more like apes than those of evolved humans, their wrists possessing trapezoid bones that would have made the delicate art of stone tool-making very difficult. Their teeth show primitive traits while their brains were little bigger than those of chimpanzees, though CT scans of skull interiors suggest they may have had cognitive skills not possessed by apes.
  13. Nevertheless, this little apeman, with poor physique, a chimp sized brain and only a limited ability to make tools, now appears to have left Africa and somehow colonised part, if not all, of south-east Asia 2m years ago.
  14. Had not the original Australian team, led by Morwood, uncovered those hobbit remains in 2004, the story of humanity's African exodus would have been considered a fairly simple affair.
  15. According to this version of events, Homo erectus evolved from apemen predecessors, such as Australopithecus africanus, in Africa and then headed off around the Old World more than 1m years ago, armed with a great physique and a modest intellect. These allowed it to settle across Africa, Asia and Europe. This diaspora was then followed by a second wave of humans - our own species, Homo sapiens – which emerged from Africa 100,000 years ago and took over the planet, replacing all pockets of its predecessors it encountered.
  16. Now a far more complex picture is emerging. Ancient apemen appear to have done the trick almost 1m years earlier. One of the major tenets of human evolution10, the story of our world conquest, is now urgently in need of revision.
  17. As to the fate of H floresiensis, that is unclear. The species disappears abruptly from the archaeological record 17,000 years ago. Why? They had apparently survived quite happily on the island for more than 1m years. So what did for them in the end?
  18. There are two competing answers. The first suggests that the species, after all the good fortune that had helped it endure the vicissitudes of life in the Malay Archipelago, ran out of luck. "There is a thick layer of ash in the Liang Bua cave above the most recent hobbit remains," says Stringer. "We now know this was caused by a major volcanic eruption which occurred about 17,000 years ago. So it may be that they were just unlucky with the local geology.” According to this vision, the little folk of Flores were wiped out by choking plumes of volcanic ash or died of starvation on an island denuded of vegetation.
  19. It would have been a pretty terrible way to go. Yet neither Stringer nor Morwood is convinced that was what happened, despite the tight link between dates of eruptions on the island and the disappearance of the species from the fossil record. Instead, they suspect a very different agent – the bloody hand of modem humans.
  20. "Look at our track record," says Morwood. When Homo sapiens entered Europe 40,000 years ago, on its route out of Africa, they would have encountered the continent's original inhabitants, the Neanderthals. Within a few millenniums, the Neanderthals had been rendered extinct.
  21. Stringer agrees. Homo sapiens left Africa about 100,000 years ago and by the time hobbits became extinct on Flores, modern humans were all over south-east Asia. "I cannot see Homo floresiensis keeping modern humans off the island. There must have been encounters between them and us. It is wonderful to speculate what might have happened when they met up, but l suspect that those moderns used up the resources that the hobbit needed to survive."

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