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Evolution on Islands
By Islomaniac | September 24, 2007
Islands are delicate and valuable ecosystems that hold the potential to harbor strange and new forms of life. Here is a new article from Wired Science about a species of miniature people just three feet tall that lived on the tiny Indonesian island of Flores.
Ever since pieces of eight tiny skeletons were found several years ago on the Indonesian island of Flores, debate has raged over whether or not the remains came from a forgotten branch of the human family tree. Many scientists have been asking themselves, sid Homo floresiensis really live just 12,000 years ago. At just three feet tall, hunting Komodo dragons, must have been like fighting dragons. Or is it possible that there was no such thing as Homo floresiensis, but instead a few freakish microcephalics — people with a genetic condition that gives them tiny brains and skulls?
In the latest chapter of this often bitter fight, a Smithsonian Institute paleoanthropologist analyzed Homo floresiensis wristbones. Their shape, he concluded, is akin to those of early hominids and chimpanzees; what’s more, the shape of wrist bones is determined early in development, before genes responsible for microcephaly kick in. The bones, he concluded, were almost surely not those of Homo sapiens.
Predictably, scientists who already believe in Homo floresiensis agreed, while scientists who don’t said the interpretations was overreaching. Penn State’s Robert Eckhardt noted that nobody’s actually done careful morphological studies of microcephalic skeletons before. The rest of the arguments against Homo floresiensis are nicely summed up by the Guardian:
Robert Martin at the Field Museum of Chicago argued in a paper last year that the Hobbit’s grapefruit-sized brain was simply too small compared with its body to be a scaled-down human species. He also said that tools found with the fossils were too advanced to have come from a creature with such a small brain. Meanwhile, Robert Eckhardt at Pennsylvania State University argued last year that Flores, the Indonesian island on which the Hobbit was found, was too
small to support a population of hunter gatherers without immigration from other islands. That would mean it was not genetically isolated and so could not have evolved into a separate species. He criticised other researchers’ willingness to get caught up in the hype and sniped that, “critical faculties were suspended on the part of many people”.
Of these, the only criticism that could still hold is Eckhardt’s point about our ignorance of microcephalic skeletons — but even that’s a long shot, given what we know of fetal development and the onset of microencephaly. The others objections fall into the category of, “We know it’s not possible because it’s just not possible” — which is fine, up until the point that new evidence shows otherwise.
It looks like the wrist bone study — and similar, upcoming analyses of foot and shoulder bones — are indeed that new evidence. Yes, scientists and the public (and science journalists) were guilty of getting caught up in the hype, but sometimes the hype is true.
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October 5th, 2007 at 12:48 pm
Gee, I hope the hype is true. The discovery of Homo floresiensis could be one of the great stories in human evolution and hopefully we’ll know more once the original research team gets back to the caves in Flores and to the other islands. Hard to believe, but their work was halted by the Indonesian government at one point further adding fuel to this mess.
Of course, I have a vested interest in this discovery, having written a fictional adventure novel called Flores Girl on the recent fossil find. If you are interested, there is more on this ongoing controversy about Homo floresiensis at www.floresgirl.com or catch the free Flores girl podcast at Pdiobooks.com.
Erik John Bertel