Human Evolution: Clear as Mud

first_imgEvolutionists speak of our descent from apes with an air of confidence and certainty, but connecting the dots requires a bit of artistic license.  Here are some examples of how any data, no matter how puzzling, can be made to fit the Darwinian picture.Stretchy Clocks:  A famous painting by Salvador Dali portrayed clocks draped over objects as if made of wet clay.  A new paper in PNAS1 announced that scientists have figured out why human beings developed much longer generation times (length of childhood) than the apes: our molecular clocks are stretchy.  “Humans have a slow molecular clock,” explained Michael Balter for [email protected]  By comparing gene differences between humans, gorillas and chimpanzees, the team decided all three clocks ticked at different rates.  Balter summarized, “Because the large difference in generation times between humans and chimps does not match the small difference between their molecular clocks, modern human generation times must have evolved recently—perhaps as early as 1 million years ago, the team calculates.”  And lo and behold, the teeth of Homo erectus seem to fit the picture of a shorter childhood.  They must be onto something.  Not everyone is convinced; Blair Hedges (U of Pennsylvania) believes that “generation time might only be one factor among many that control the molecular clock,” Balter wrote.Neanderthal Nimrod:  Forget the beetle-brained, stoop-shouldered Alley Oop image of Neanderthal Man.  Now we’re told by EurekAlert that they were ahead of the game: Neanderthals were just as good at hunting as modern man (probably better, since hunting is a lost art except in the frozen foods section).  Since the superior skill of modern man was part of the story of the disappearance of Neanderthals, “This study has important implications for debates surrounding behavioral evolution and the practices that eventually allowed modern humans like ourselves to displace other closely-related species.”  Maybe the moderns did better in Social Studies, the article suggests.Neo-Neanderthal:  Speaking of Neanderthal Man, a paper in Nature last November argued that Neanderthals apparently coexisted with moderns in the same cave.2  They used radiocarbon and stratigraphic analysis in a French cave to conclude, “These data strongly support the chronological coexistence—and therefore potential demographic and cultural interactions—between the last Neanderthal and the earliest anatomically and behaviourally modern human populations in western Europe.”  See also a related article on MSNBC.Face the Facts:  Last month in PNAS,3 a team of anthropologists kicked out another prop holding up the standard story of where Europeans came from.  A study of 24 facial features of human fossils around Europe found only “a questionable contribution of the Neolithic and the Bronze Age to European craniofacial form.” The surprise is that the Neolithic peoples of Europe and their Bronze Age successors are not closely related to the modern inhabitants, although the prehistoric/modern ties are somewhat more apparent in southern Europe.  It is a further surprise that the Epipalaeolithic Natufian of Israel from whom the Neolithic realm was assumed to arise has a clear link to Sub-Saharan Africa.  Basques and Canary Islanders are clearly associated with modern Europeans.  When canonical variates are plotted, neither sample ties in with Cro-Magnon as was once suggested. (Emphasis added in all quotes.)So what’s my new line?  “The data treated here support the idea that the Neolithic moved out of the Near East into the circum-Mediterranean areas and Europe by a process of demic diffusion but that subsequently the in situ residents of those areas, derived from the Late Pleistocene inhabitants [sic], absorbed both the agricultural life way and the people who had brought it.”  Any questions?Cannibal Animal:  Mike Balter explored a recent claim on the human evolution story in ScienceNow: are we descended from cannibals?  Apparently not; an earlier study appears flawed.  Thank God (see our cannibal parable).Ethiopia: The Place to Be:  Rex Dalton ventured out with paleoanthropologists to get the view from Afar (Ethiopia, that is), where rival teams of researchers with “hominid fever” dodge bullets of political rivals, avoid lions, endure oppressive heat, protect their secret spots and bounce around on rattletrap trucks to search for their precious quarry: hominid bones.  In his Indiana-Jones style account in Nature,4 Dalton gave more an impression of a gold rush than a reliable scientific enterprise, complete with claim jumpers and inflated announcements.  “This is where it all began,” they are convinced, as Dalton “gets on the trail with a team of devoted experts who just live for the next find.”  A few, like Tim White, are trying to be careful.  “White dislikes what he calls ‘hominid treasure hunts’, where researchers move in for short field visits to grab hominids and then headlines,” Dalton wrote.  As for White’s most recent find, it was a surprise: “hominids – then the earliest known – lived in a wooded environment, not a savannah as previously thought”  (see also 09/01/2005 story).  Any consensus theory seems Afar way off.Egypt U:  Science,5 however, announced last October that Egypt is the place to be.  A find in Egypt by Seiffert et al.6 was described by Jaeger and Marivaux as “Shaking the Earliest Branches of Anthropoid Primate Evolution.”  The paper began, “Early anthropoid evolution in Afro-Arabia is poorly documented, with only a few isolated teeth known from before ~35 million years ago….”Spanish-American War:  Believers in the 40,000-year-old Mexican footprints are not giving up without a fight, reported BBC News (see 11/30/2005 story).  Dr. Silvia Gonzalez seems to have a ready answer for every skeptical criticism.  That makes some of her critics even more skeptical.Intercontinental Ballistics:  National Geographic News last month entertained the novel suggestion that the favored “Out of Africa” theory might be wrong.  Maybe they evolved from Asia.  Interesting; provocative; possibly persuasive; not convinced – those represent some reactions so far.  Nature studied the suggestion also7:  “We show here that it is time to develop alternatives to one of palaeoanthropology’s most basic paradigms: ‘Out of Africa 1’,” wrote Robin Dennell and Wil Roebroeks.  The more basic paradigm, of course, is that mankind did evolve from somewhere.  That paradigm is not on trial. (Visited 13 times, 1 visits today)FacebookTwitterPinterestSave分享0 1Elango et al., “Variable molecular clocks in hominoids,” Proceedings of the National Academy of Sciences USA, published online before print January 23, 2006, 10.1073/pnas.0510716103.2Gravina, Mellars and Ramsey, “Radiocarbon dating of interstratified Neanderthal and early modern human occupations at the Chatelperronian type-site,” Nature 438, 51-56 (3 November 2005) | doi: 10.1038/nature04006.3Brace et al., “ The questionable contribution of the Neolithic and the Bronze Age to European craniofacial form,” Proceedings of the National Academy of Sciences USA, published online before print December 21, 2005, 10.1073/pnas.0509801102.4Rex Dalton, “Ethiopia: Awash with fossils,” Nature 439, 14-16 (5 January 2006) | doi:10.1038/439014a.5Jaeger and Marivaux, “Shaking the Earliest Branches of Anthropoid Primate Evolution,” Science, Vol 310, Issue 5746, 244-245 , 14 October 2005, [DOI: 10.1126/science.1118124].6Seiffert et al., “Basal Anthropoids from Egypt and the Antiquity of Africa’s Higher Primate Radiation,” Science, Vol 310, Issue 5746, 300-304 , 14 October 2005, [DOI: 10.1126/science.1116569].7Dennell and Roebroeks, “An Asian perspective on early human dispersal from Africa,” Nature 438, 1099-1104 (22 December 2005) | doi:10.1038/nature04259.Anyone who has worked around scientists enough knows that a community of specialists in a given subject takes on the character of a club.  Scientific conferences have a certain social structure and networking protocol similar to a small town.  Everyone knows everyone else, and gossip is a favorite pastime.  While exciting finds and new twists on the plot are welcome (though usually greeted somewhat more dispassionately than at a healing service), there is a certain code that guards against anyone straying too far out of bounds.  You can wear a cowboy hat, but act like a maverick and you are likely to be shunned more than overtly criticized.  For many, that is too much a price to pay.  The respect of one’s peers is vital for a scientific career.    So here we have the paleoanthropology crowd, roaming around the globe or wading through rivers of genes for their nuggets, trying to fit them into a huge crown for Charlie.  The crown is much bigger than the specks found so far, so it will take a long time to complete.  To finance these expeditions, the participants need to convince their home institutions, usually funded with government grants, that it is all worthwhile because we are getting warmer looking for just the little piece that fits into the niche we have selected to work on.  (The shape and style of the crown, of course, has already been decided, along with the wearer; only the details of gem placement provide some artistic license.)    Is this really a search for truth?  Could it be a massive case of self-deception that relishes the process more than certainty?  Might it be that Big Science is in a rut, entrenching a social protocol guaranteed to keep mavericks in line and preserve paradigmatic presuppositions?  You can see why any outsider looking at this game and deciding that it is all bunk, all unsupported and contradictory nonsense that does nothing to disprove the belief of the majority of people on this planet that humans were created, would not receive a very friendly reception.  It’s too late to turn back now.  Too much is riding on it.  The show must go on.  (And keep those funds flowing.)last_img

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