 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
Natural Science Forum / Biology / Paleontology / September 2006Modern humans, not Neandertals, may be evolution's 'odd man out'
http://www.eurekalert.org/pub_releases/2006-09/wuis-mhn090706.php Looking incorrectly at Neandertals Could it be that in the great evolutionary "family tree," it is we Modern Humans, not the brow-ridged, large-nosed Neandertals, who are the odd uncle out? New research published in the August, 2006 journal Current Anthropology by Neandertal and early modern human expert, Erik Trinkaus, professor of anthropology at Washington University in St. Louis, suggests that rather than the standard straight line from chimps to early humans to us with Neandertals off on a side graph, it's equally valid, perhaps more valid based on what the fossils tell us, that the straight line should be from the common ancestor to the Neandertals, and the Modern Humans should be the branch off that. Trinkaus has spent years examining the fossil record and began to realize that maybe researchers have been looking at our ancient ancestors the wrong way. Trinkaus combed through the fossil record, identifying traits which seemed to be genetic markers - those not greatly influenced by environment, life ways and wear and tear. He was careful to examine traits that appear to be largely independent of each other to avoid redundancy. "I wanted to see to what extent Neandertals are derived, that is distinct, from the ancestral form. I also wanted to see the extent to which modern humans are derived relative to the ancestral form," Trinkaus says. "What I came up with is that modern humans have about twice as many uniquely derived traits than do the Neandertals." "In the broader sweep of human evolution," says Trinkaus, "the more unusual group is not Neandertals, whom we tend to look at as strange, weird and unusual, but it's us - Modern Humans. The more academic implication of this research is that we should not be trying to explain the Neandertals, which is what most people have tried to do, including myself, in the past. We wonder why Neandertals look unusual and we want to explain that. What I'm saying is that we've been asking the wrong questions." The most unusual characteristics throughout human anatomy occur in Modern Humans, argues Trinkaus. "If we want to better understand human evolution, we should be asking why Modern Humans are so unusual, not why the Neandertals are divergent. Modern Humans, for example, are the only people who lack brow ridges. We are the only ones who have seriously shortened faces. We are the only ones with very reduced internal nasal cavities. We also have a number of detailed features of the limb skeleton that are unique. "Every paleontologist will define the traits a little differently," Trinkaus admits. "If you really wanted to, you could make the case that Neandertals look stranger than we do. But if you are reasonably honest about it, I think it would be extraordinarily difficult to make Neandertals more derived than Modern Humans." ### Full text of the article is located online at, http://www.journals.uchicago.edu/CA/journal/issues/v47n4/120413/120413.web.pdf > http://www.eurekalert.org/pub_releases/2006-09/wuis-mhn090706.php > > Looking incorrectly at Neandertals > Could it be that in the great evolutionary "family tree," it is we Modern > Humans, not the brow-ridged, large-nosed Neandertals, who are the odd uncle > out? [snip] What a silly argument. Do human paleontologists really still argue about this sort of thing? It reminds me of the big controversy in ornithology in the 1940's and '50's over whether crows or finches should be listed last in a linear classification of the passerines. Most fields of systematics are way beyond such pointless argument. Fortunately. > ### > Full text of the article is located online at, > http://www.journals.uchicago.edu/CA/journal/issues/v47n4/120413/120413.web.pdf >> http://www.eurekalert.org/pub_releases/2006-09/wuis-mhn090706.php >> [quoted text clipped - 4 lines] > >[snip] >What a silly argument. Do human paleontologists really still argue about >this sort of thing? It reminds me of the big controversy in ornithology >in the 1940's and '50's over whether crows or finches should be listed >last in a linear classification of the passerines. Even aside from that, isn't "odd man out" exactly what most people would expect modern humans to be? Doesn't the popular image of the human family tree look something like this: Highly evolved Us ^ | | Whole bunch of undifferentiated "Ape-Men" ^ | | Apes I think it makes perfect sense to point out that, in a group of related species, some resemble the LCA more closely than others. But I certainly never thought of modern humans as being less derived than Neandertals, and if anybody else did I'm kind of surprised.  SignatureJohn Brock jbrock@panix.com > >> http://www.eurekalert.org/pub_releases/2006-09/wuis-mhn090706.php > >> [quoted text clipped - 28 lines] > But I certainly never thought of modern humans as being less derived > than Neandertals, and if anybody else did I'm kind of surprised. Well I've read the paper now, and it seems to me that what Trinkaus is trying to do is quantify the degree of evolution Ns have had compared to Ss, morphologically, since their common ancestor. The problem lies not in his assigning polarities, for he relies on a cladistic topology for that, but on the reference class - i.e., which characters are chosen for comparison. He says that there are plesiomorphic, synapomorphic and autapomorphic traits in both species but that humans have "more" autapomorphies than neandertals, while the latter have more plesiomorphic... [for the traits examined!]. It isn't an obvious mistake, though, and the data is presumably interesting to specialists. SignatureJohn S. Wilkins, Postdoctoral Research Fellow, Biohumanities Project University of Queensland - Blog: scienceblogs.com/evolvingthoughts "He used... sarcasm. He knew all the tricks, dramatic irony, metaphor, bathos, puns, parody, litotes and... satire. He was vicious." >>>>http://www.eurekalert.org/pub_releases/2006-09/wuis-mhn090706.php >>>> [quoted text clipped - 41 lines] > examined!]. It isn't an obvious mistake, though, and the data is > presumably interesting to specialists. I can see being interested in the evolution of particular characters. But I can't see being interested in some kind of global "apomorphy score". Unless, as with molecular evolution, the characters being summed really are comparable and the score says something about evolutionary processes. I don't see that happening here. > >>>>http://www.eurekalert.org/pub_releases/2006-09/wuis-mhn090706.php > >>>> [quoted text clipped - 47 lines] > really are comparable and the score says something about evolutionary > processes. I don't see that happening here. Have you got the paper? He has a discussion on the chocie of traits on the basis of the independence of traits from each other, "biologically primary" traits, homology and degrees of palsticity. The six groups are neurocranial, facial, dental, axial (spinal), upper limb, and lower limb. Summing over these he finds that neandertals are around 26% synapomorphic with early modern humans, 25% autapomorphic, and EM humans are around 48% autapomorphic. Late modern humans relative to Ns are around 53% autapomorphic, and Ns are 23% synapomorphic with LM humans. What this teaches us, I can't say. For those traits there are clear signals that humans are the more derived, but the choice of traits may be based, contingently, on what is of interest to human anthropologists, so it may be special pleading. SignatureJohn S. Wilkins, Postdoctoral Research Fellow, Biohumanities Project University of Queensland - Blog: scienceblogs.com/evolvingthoughts "He used... sarcasm. He knew all the tricks, dramatic irony, metaphor, bathos, puns, parody, litotes and... satire. He was vicious." >>>>>>http://www.eurekalert.org/pub_releases/2006-09/wuis-mhn090706.php >>>>>> [quoted text clipped - 49 lines] > > Have you got the paper? No. > He has a discussion on the chocie of traits on > the basis of the independence of traits from each other, "biologically [quoted text clipped - 9 lines] > be based, contingently, on what is of interest to human anthropologists, > so it may be special pleading. If humans are more derived for these traits, why should we care? What does it tell us about evolution or about ourselves? Or about neanderthals, for that matter? > > What this teaches us, I can't say. For those traits there are clear > > signals that humans are the more derived, but the choice of traits may [quoted text clipped - 4 lines] > does it tell us about evolution or about ourselves? Or about > neanderthals, for that matter? Well Trinkhaus *is* a Neandertal specialist. I think he's trying to overcoem the folk notion, which many anthropologists tend to share on his account, that Neandertals are somehow a deviation from the hominid norm, because they deviate from us. In short he's *objecting* to the great chain notion that was mentioned further upthread. Note that I'm not defending him or his claim here. I'm just trying to put it in its best light. It is worth a read (as are the critical comments at the back of it). SignatureJohn S. Wilkins, Postdoctoral Research Fellow, Biohumanities Project University of Queensland - Blog: scienceblogs.com/evolvingthoughts "He used... sarcasm. He knew all the tricks, dramatic irony, metaphor, bathos, puns, parody, litotes and... satire. He was vicious." >>>What this teaches us, I can't say. For those traits there are clear >>>signals that humans are the more derived, but the choice of traits may [quoted text clipped - 10 lines] > norm, because they deviate from us. In short he's *objecting* to the > great chain notion that was mentioned further upthread. Actually, it seems as if he's supporting the great chain. Neanderthals are primitive, a mere minor side chain, while we apomoprhic H. sapiens follow the main line of progress. > Note that I'm not defending him or his claim here. I'm just trying to > put it in its best light. It is worth a read (as are the critical > comments at the back of it). > >>>What this teaches us, I can't say. For those traits there are clear > >>>signals that humans are the more derived, but the choice of traits may [quoted text clipped - 14 lines] > are primitive, a mere minor side chain, while we apomoprhic H. sapiens > follow the main line of progress. That's the opposite of his argument, John. Read the paper. > > Note that I'm not defending him or his claim here. I'm just trying to > > put it in its best light. It is worth a read (as are the critical > > comments at the back of it). SignatureJohn S. Wilkins, Postdoctoral Research Fellow, Biohumanities Project University of Queensland - Blog: scienceblogs.com/evolvingthoughts "He used... sarcasm. He knew all the tricks, dramatic irony, metaphor, bathos, puns, parody, litotes and... satire. He was vicious." >>>>>What this teaches us, I can't say. For those traits there are clear >>>>>signals that humans are the more derived, but the choice of traits may [quoted text clipped - 16 lines] > > That's the opposite of his argument, John. Read the paper. That would take all the fun out of it. And I don't have access. But I don't see how he can make the opposite argument based on the data he presents. And it seems to be a pointless and obvious thing to say. If human paleontology really is stuck in the great chain of being, that's very unfortunate. I guess we can't look at ourselves objectively. >>>Note that I'm not defending him or his claim here. I'm just trying to >>>put it in its best light. It is worth a read (as are the critical >>>comments at the back of it). >>>>>What this teaches us, I can't say. For those traits there are clear >>>>>signals that humans are the more derived, but the choice of traits may [quoted text clipped - 16 lines] > > That's the opposite of his argument, John. Read the paper. Yeah, OK. I read the paper and the comments. He's not arguing against the chain of being. It doesn't come up. Though in fact his argument makes the chain more plausible, as does anything that shortens branches that aren't on the lineage leading to us. It appears that the state of human paleontology is encumbered with all manner of odd beliefs and basic philosophical flaws, if we can believe the author and his commentors. So simple a message shouldn't have to be stated, and in other fields it wouldn't be. The message is essentially that we should look at the actual specimens, get a broad sample, consider individual variation, not pigeonhole specimens a priori, and base our ideas on actual data. Crikey. And there still seems an unhealthy interest in the overal derived nature of entire taxa, rather than individual characters. |
Reply to this Message |
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2009 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.