The Missing Link

Arthritis?
Arthritis?Are you saying that arthritis causes:
1. A long low brain case that bulges in back
2. Larger overall bulk
3. Strong, thick bones
4. Protruding jaw
5. Sloping forehead
6. Large muscle connections indicative of large muscle mass and great strengthThat doesn't really sound like arthritis to me, I must say.

Certain Neanderthals discovered were shown to have arthritis. These were the Neanderthals in the European areas. Interestingly the European Neanderthals show the sloped, massive facial features that have become common in unscientific drawings found in scientific textbooks.Surely you do not deny that some of the Neanderthal's did have arthritis? Paleoantrhopologist Richard Leakey states this quite obviously in his Chapter on Neanderthal Man in 'The Making of Mankind.' With this knowledge I have already explained why these certain Neanderthals had this bone disease and how it is quite conceivable that it did cause certain features in them that were not observed in other discovered Neanderthals.But your post asks the question. Why ask the question however, when it is obvious you have already formed your answer? (Notice I did not say 'the' answer).Apostle

He was asking for your answer. As you say, you can guess what his is. What is yours?

Hi Apostle! Just so you know, Leakey’s Making of Mankind is not a good source for information on hominin evolution. It was published in 1981, and was the accompanying book to a TV series of the same name. It therefore presents the late-70s view. Which was, of course, fine at the time. But things have moved on a lot since then.Most crucially, in common with many palaeoanthropologists of the time, he refused to acknowledge the genetic / ‘molecular clock’ evidence, which placed the chimp-human split at 5mya. Instead, they stuck with the previous (and somewhat creationistic!) view that humans were rather more separate from other animals, with the divergence at around 15mya. That put Ramapithecus in the frame as the earliest of our lineage.I’m surprised that you haven’t included that in the list of things you want to criticise. Because Ramapithecus (now regarded as Sivapithecus) was known from just a few fragments at the time. More complete fossils since have confirmed it as actually closer to orangutans. Scratch another alleged ancestor from out lineage? Not in the slightest. The molecular and fossil data now is converging on a 7-4mya chimp-human split.Interestingly, it is even possible that some Australopithecines were actually ancestral to the other African apes, as Gribbin & Cherfas ‘popularly’, and Verhaegen more formally, have argued. See eg Verhaegen
here and here. This would explain both the lack of ‘great ape’ fossils, and also why there are A’piths before the later dates derived from the molecular clock. In effect, the ‘apes’ would be derived from a human-like ancestor! There are however a number of problems with this, most importantly that it would mean chimps and gorillas are secondarily quadrupedal -- having returned to generally four-legged locomotion from being obligately bipedal.. and have lost all traces of having been totally two-footed. But I mention it because it’s interesting, may be right... and is an area where human evolution may yet have to be revised.The key point here is that the path of human evolution can be, and often has been, revised in light of new evidence. That’s what makes it a science. But none of the evidene contradicts the claim that humans did evolve, only the exact route taken. Sure. Some Neanderthals had arthritis. Shit, our old cat had arthritis. The point is that we know what arthritis looks like and what effects it has. And none of these cause the diagnostic features of Neanderthals: long-n-low cranial vault, occipital ‘bun’, heavy musculature and bones, retromolar gap, lack of a mental process (chin bone), midfacial prognathism, equal-length first and second bones of the thumb and big toe, and so on.None of these things are caused by arthritis; nobody is denying that Neanderthals were ‘human’; nobody is denying that they were not actually 'us'; nobody thinksthat they were ancestral to ‘us’.These things being the case, there’s little point in trying to prise an answer from you on the arthritis matter (how it could cause these features listed). Can we move on now?Cheers, DT[This message has been edited by Darwinsterrier, 12-02-2003]

Sorry? Are you sure about that?

Heh! Define 'us'!Not Homo sapiens sapiens, but rather, either a subspecies or a separate species of Homo. Not of our direct lineage, but a recent side-branch from us. Not us in the sense that you are (probably) not a member of my immediate family.I apologise if I missed anyone saying otherwise... and will happily argue against them!Cheers, DT

Cool. Just wanted to clarify.I would have only taken Homo sapiens sapiens to be 'us', if you're using it in a broader sense then that's fine.Incidently, do you know any justification for calling Neanderthals Homo sapiens neanderthalis rather than Homo neanderthalis? Since the evidence seems to suggest Neanderthals and anatomically modern humans didn't interbreed (despite ample opportunity), I would argue they should be considered a seperate species, rather than subspecies.

I agree with you, and by the same reasoning I’m a dedicated ‘splitter’. As you’re probably aware, the line between closely related species is often blurred, even with living creatures (and is totally up the spout with other kingdoms ).Curtis, Swisher and Lewin in Java Man put it quite well: if you put a bunch of closely related deer species (iirc) skeletons in front of an anatomist, they might well put them in the same single species. The point is that much of what makes a species separate is not fossilisable... hence, if two fossils are skeletally distinct, it is more plausible that they are distinct species, rather than a single one. Hence, I’m a splitter not a lumper.The separateness of neanderthalensis, ie it being a species in its own right, seems to be the more prevalent view these days, but many palaeoanthropologists (hell, I wish there was a nice abbreviation of that damned word!) are nevertheless lumpers. (Classic example: whether OH24 and KNM-ER 1470 are female and male of the same single species, Homo habilis, or whether they represent different species, habilis and rudolfensis respectively.) It is perfectly possible for a single species to have significant variation, especially sexual dimorphism. Which is why the lumpers can think as they do.It’s basically very difficult, and comes down to which you find more plausible: of the meagre remains we have, is something like neanderthalensis / sapiens, or habilis / rudolfensis, simple morphological variation -- regional, sexual etc -- within a species, or is it actually more fundamental. In a nutshell, the evidence is equivocal. Like I say, it’s often hard enough telling living species apart (or ‘telling them together’ ). With fossils, we may never know.The waters are muddied further, of course, when it comes to distinguishing species across time. At what point did species X become species Y? When did African erectus (say) become archaic sapiens? If one was descended from the other, then at no single point did one become the other! And with older fossils, there’s the problem of resolution -- were the two (or one) species contemporary? They may be within 100k years of each other... which is at least 5,000 generations, plenty of time for the sorts of differences we’re talking about to accumulate.You cannot draw a definitive line on a continuum: drawing a line is simply the wrong image. A late neanderthal might not have been able to interbreed with a sapiens... but an earlier one would have been able to with its contemporary proto-sapienses, because originally they were the same species. It’s just a question of how far had each diverged -- completely, or just partially?It tends to look these days as if Neanderthals were a separate species, but the clincher is, as you say, the mtDNA evidence of a lack of significant interbreeding. But though I’ve not read much of his, Trinkaus is no fool, and is a lumper. So I may be wrong...So much for off the top of my head ramblings; I’ll check my books tonight and see if there’s anything more concrete to report...Cheers, DT

Darwinsterrier, you made a good point here!

quote:

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Interestingly, it is even possible that some Australopithecines were actually ancestral to the other African apes, as Gribbin & Cherfas ‘popularly’, and Verhaegen more formally, have argued. See eg Verhaegen here and here. This would explain both the lack of ‘great ape’ fossils, and also why there are A’piths before the later dates derived from the molecular clock. In effect, the ‘apes’ would be derived from a human-like ancestor! There are however a number of problems with this, most importantly that it would mean chimps and gorillas are secondarily quadrupedal -- having returned to generally four-legged locomotion from being obligately bipedal.. and have lost all traces of having been totally two-footed. But I mention it because it’s interesting, may be right... and is an area where human evolution may yet have to be revised.

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I came to quite the same conclusion after reading Svend Palm's essay here and Robin Crompton's works (model of primate movements). The most primitive apes, the gibbons, are not knuckle-walkers. When they have to walk on the ground they do it with thir hind legs.http://www.chass.utoronto.ca/anthropology/ Faculty/Begun/originbip.pdf
My own opinion on this (check under 'No Half-Bipedalism')

You completely failed to answer my question - does arthritis explain the distinctive features of Neanderthal skeletons? To me the answer is obvious: Arthritis does not explain these features of the Neaderthal.Am I wrong?Of course I don't deny that some Neanderthals had arthritis. My point is that arthritis explains none of the distinctive features of Neanderthal skeletons, despite your assertion that it does. Why do you assert this? Why don't you back up your assertion when asked directly? Why do you decline to back up your assertion simply because you infer - correctly - that I disagree with you? If we all agreed, this wouldn't be much of a debate board, would it?

Transitional Vertebrate Fossils FAQWhew, that was tough on my arthritic fingers!

Just out of curiosity, was it the color tone of the picture of the hominid crania that most offended you?

There are now hundreds of fossil hominids from numerous horizons between 6.0 million years ago and the present. The arguement of whether Neaderthal features was caused by arthritis is silly. There are not living people in the 6 blllion around today who turn into neaderthals after arthritis. I any case, Neaderthals are not the only fossil hominids. There are lots and lots. Want more picutres?hominids indexCan anyone really look at these pictures and not see what is going on? The answer is of course, yes. Why? Because human brains have been natually selected to desire social acceptance more than truth (can anyone say Spanish Inquisition?).

Just wondering whre Apostle went...?

Where did you go ? Just because your philosophic friends closed the topic did you think you could escape me ? What about your replies to the scientific evidence that was posted ? I know you have answers but you don't until they are posted. Did you know we are debating the Pilbeam quote in Human Origins ?