Tuesday 18 September 2012

Human Evolutionary Theory In Tatters: Proof From the 2012 CALPE Conference in Gibraltar

A tip o' my hat to Bob Muckle, who tweeted about this BBC story. It tells of Ian Tattersall's extraordinary comments, made Thursday, September 13, 2012, about the One True Force underlying all of the evolution of bipedal apes, of which the only living exponent is us, and which includes everything from Sahelanthropus through Ardipithecus and Australopithecus to the Neanderthals. That Tattersall's hypothesis takes center stage at a prestigious global conference demonstrates to me just what a confused state in which human evolutionary theory finds itself in the early twenty-first century. [I'm being fair--at best Tattersall's is a suggestion about how things might have been, and as such doesn't rise above the level of a startling, but untestable, hypothesis.] Let us go then, you and I. Like Ardipithecus ramidus I'm gonna go out on a limb--my favourite place, evah.  
Ardipithecus ramidus
This weekend in Gibraltar marks the triennial renewal of the CALPE Conferences on human evolution, begun in 1998 on the sesquicentennial of the Forbes Quarry's skull. According to this story in the Gibraltar Chronicle
The theme of this year’s conference is 'The Human Niche: Ecology, Behaviour and Culture in the Genus Homo.' As customary, the conference brings together some of the world’s leading specialists but this year there is a difference. As Professor Clive Finlayson, organiser of the conference will put it in his introductory remarks on Thursday, ‘in selecting the speakers for this conference I went for a mix of established leaders in their field and young researchers who are making important contributions.’ So novelty is the order of the day in this conference which, for the first time, offers a platform for new talent. The programme has been structured in such a way that the conference will have an appeal to specialists but also to the general public interested in this fascinating subject. Public interest in the Gorham’s and Vanguard Caves excavations, which this year ran for six weeks and ended last Friday, has been great. Now they have the opportunity of hearing, first hand, the results of such work and that of others all over the world. Professor Finlayson describes this year’s conference as a landmark, one in which he hopes the current human evolution paradigm will be replaced by a new approach, one that puts ecology in the forefront. It has attracted important media coverage with several reporters from important journals and news channels flying out to Gibraltar from as far as the United States. Gibraltar is fast becoming one of the world’s major centres for such studies and conferences such as this one will help to reinforce the message of the Rock’s vital role. With a bid for World Heritage Status for the Gorham’s Cave Complex now in preparation, this year’s Calpe Conference is a major cog in the build up process. 
 With that kind of hype, it's hard to imagine any of the major invitees trotting out a really smelly red herring. But out one came, just the same. And from Ian Tattersall, no less! It seems that Ian has intuited the single behavioural factor underpinning the rapid evolution of the bipedal apes. Competition. He calls it something else, and he adds some behavioural qualifiers, like 'violent' and 'intergroup,' but at bottom it's plain old competition. Nothing new there, except that he's positing our more rapid evolution based on presumably grander-scale conflict, or, well, see for yourself.
     Granted, none of us but those lucky enough to have been there will have heard the whole story, so we'll just have to rely on the usually reliable BBC coverage to illuminate us. Apparently Ian Tattersall thinks that, as a group, the bipedal apes have come a long way in a comparatively brief span of time. He cites physical characteristics such as brain size and dental changes as part of our unusually rapid evolution. However, to make his point, Tattersall must do a little muddying of the waters of human evolution--a bit of palaeoanthropological sleight of hand, as I see it. 
WT 15000, Homo erectus/ergaster
     The first of the author's overly broad overviews is apparent in this quote/paraphrase from the BBC article: 
The increase in brain size seems to have coincided with a modern physique characterised by a linear shape, long legs and relatively narrow hips. These features can already be seen in the skeleton of the 'Turkana boy' [WT 15000] from Kenya, who lived about two million years ago. This contrasts sharply with the short legs and long arms of the Turkana boy's antecedent 'Lucy' (Australopithecus afarensis), who lived in Ethiopia about one million years earlier. 
Wait a second! Have I missed something? Or is this eminent scholar downplaying not only modern human variation, but also the variety of leg/arm ratios in our fossil ancestry when you look beyond the two forms he mentions above? Neanderthal and modern human One wonders at Tattersall's rather unfairly phrased comparison in support of his premising argument--like comparing apples to oranges and being surprised when they're found to be different. And since when is 'linear' a discipline-appropriate descriptor for the skeletal differences between early and late bipedal apes? 
My favourites!
The author is quick to bring culture into the frame, but even then he downplays its valence as an engine of 'rapid' evolution in bipedal apes. The BBC article continues...
Human culture was probably the special, consistently present ingredient that drove the continuing fast pace of change in our lineage after we left the forests, said Prof Tattersall, but not in the way that some other researchers have proposed. But Prof Tattersall said the way our technology transformed in fits and starts, along with the way these changes were often separated from biological evolution, meant this idea was not as good a fit for what is seen in the archaeological and fossil records. Aggression between small, distinct human groups in the past is one of the major remaining agents of such changes, he said. 'Inter-group conflict would certainly have placed a premium on such correlates of neural function as planning and throwing,' Prof Tattersall explained. Chimps also have culture, but have not experienced such accelerated evolution. 'If we were somehow able to implicate conflict among groups as a selective agent for increasing intelligence within groups, this might explain the otherwise quite mystifying independent increases in brain size that we see in several different lineages within the genus Homo.' Such conflict could be seen as a form of predation. And, predation is regarded as a classic example of the 'Red Queen' hypothesis whereby prey and predator become faster or more cunning in a self-reinforcing way. 
When Ian says 'if we were somehow able to implicate blah, blah, blah' he's really tanking. Talk about trying out wacky new ideas in a conference setting! Except. This ain't no trial balloon--not if you remember Robert Ardrey's African Genesis and The Territorial Imperative, or Desmond Morris's The Naked Ape. Tattersall's isn't a novel suggestion even if you strip it of the sensationalism, and ignore his naïve view of the cultural tool-kit of our fossil relations. 
[I guess it's a no-brainer that I can't mutely stand by while this author, like so many others, invokes the holy trinity of human evolution: clothing, fire and shelter as a means by which our 'relatively frail bodies' managed to cope with the climatic and other environmental vicissitudes of palaeolithic life.] 
At bottom, this author's major thesis is that competition brought about evolutionary change. I didn't feel the earth shake. I doubt that you did. 
     Allright! Allright! Maybe I'm being too harsh. Maybe the BBC took what Tattersall said out of context. But if this is what Tattersall is thinking in 2012, and if this is the epitome of human evolutionary theory--as the conference organizers seem to think--I have to say that it proves something I've long believed, that the discipline of human palaeontology is in crisis and human evolutionary theory is in tatters.

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