John Langdon wrote:JL3: But that does not make them appropriate.
How do you know if they are appropriate or not? As we have no good candidate paleospecies for the LCA, we simply don't know.
Surely looking at the contexts where extant great apes (our closest relatives) do switch to bipedalism is a reasonable strategy. Jolly did with baboons, Livingstone with gorillas, Keith with gibbons, Hunt with chimps - and even very recently Crompton et al did practically the same thing - and made it to the front cover of Science, no less - by doing the same thing with Orang Utans in 2007. Why, suddenly, is it no longer de rigeur to do that? As Dan Dennett wrote about the counter arguments to Elaine Morgan's work - arguing about inappropriateness seems a bit thin and ad hoc. If looking at context of bipedalism in extant apes is not inappropriate, what's IS?
John Langdon wrote:JL3: ". . . so all this is conjecture anyway." That describes all discussion of evolutionary scenarios.
Sure, but it seems only those scenarios avoiding the dreaded 'a' factor are taken seriously. Mention wading and people start to raise their eye brows and think of Von Daniken. Why's that, John? Can't anthropologists differentiate between the plausibility that aliens might have come down from outer space, affected meso-aerican culture and then cleared off again without trace, and the possibility that wading through shallow water (to name just one idea) might have made us more bipedal? I think some of you guys have some real problems if that's the case!
John Langdon wrote:JL3: If it has not been discussed, I can't argue with you about it. Why has it been ignored? Many evolutionay scenarios (conjectures) are offered, but unless anthropologists find them really compelling they get ignored. That includes mose terrestrial scenarios. Kingdon, a respected expert on African mammals, wrote a whole book promoting his idea. I can't even remember what it was. Aside from a couple of book reviews I have never seen it cited. Nina Jablonski, is a prolific publisher in anthropology, She wrote an article in JHE on a sexual selection hypothesis for bipedalism and a book on skin coloration. I have never seen either discussed in the literature. Beyond a debate along the lines of "I think hypothesis A is more reasonable." "No, I think B is better." Unless someone can find a new way to generate evidnece, there simply is not much to say about evolutionary conjectures.
Consider David Horrobin's journal Medical Hypotheses. Every month a couple of dozen ideas are published -- well reasoned but unsupported by critical study. I am sure the authors feel passionately about their ideas; but I am also sure 90% of them are completely ignored.
Kingdon's idea is "squat feeding" - another odd idea in a series of 30+. The wading idea is not odd. It's obvious. What other model can say - place 20 otherwise quadrupedal apes in scenario x and they will all switch to bipedal locomotion (not just a temporary posture) for as long as the conditions prevail? I put it to you that NONE can, and yet this is the idea that is not only ignored it's sneered at (e.g. Crompton's review of Jo Myers Thompson's piece).
I guess what I meant is that it's not taken seriously in university texts. Jablonski & Chapman's 'threat display' idea is very popular in those, actually. I guess Kingdon's, like Filler's and Crompton's, are just too new. The wading idea's been around for 50 years and it hardly ever gets a mention. Your review of them in one such text (which I forget) was one of the few that did - and I congratulate you for that.
John Langdon wrote:JL3: Once more, my argument is that there are multiple hypotheses about bipedalism (and other features) most of which cannot be directly tested or disproved. (Some, however, are clearly weaker than others.) In the case of the examples presented in my article, they depend on different starting assumptions (umbrellas, paradigms). The assumptions themselves to not confer parsimony; but some assumptions are more parsimonious than others. I do think the AAH is unparsimonious and weak in its initial assumptions for reasons stated in the article.
I did not try to evaluate most of the specific hypotheses; however, in rejecting the starting assumptions of the AAH, I believe they are rendered useless.
So, can I - or can I not - from now on claim that even John Langdon argues that his paper was not meant to be a refutation of the so-called "aquatic ape"? Would that be a misrepresentation of your view? If not, it means that there is no refutation whatsoever in a 1st class anthro journal - and certainly nothing at all to reject the wading hypothesis.
Frankly, John, I think that if all your paper was meant to do was point out that there are other possible explanations for all the traits claimed by Morgan as being potentially better explained by wading, swimming and diving - it's rather underwhelming. Elaine made the very same point herself many times and, actually, for more thoroughly than you did. For example, on the discussion of nakedness you didn't mention the Pagel & Bodmer parasite idea or the even the classic sexual selection argument.
But this is the point you seem to be evading. It is YOUR OWN, PERSONAL starting assumption (Ok, and I grant you, many others too), that you contrive as a straw man, that has led you to dismiss the idea as "useless". Many others have read Elaine's books and not thought anything near as extreme as that. Colin Groves, David Attenborough, Philip Tobias and Dan Dennett to name perhaps the 4 most prominent. My assumption was that Morgan was overstating the case slight just as a way of making it more dramatic. I never thought the idea as being anything more than just that our ancestors were RELATIVELY (and only SLIGHTLY) MORE aquatic than our ape cousins.
Anyone can reject any idea if they are allowed to exaggerate it to breaking point. It's what creationists do with Darwinism all the time.
John Langdon wrote:L3: Natural selection won't operate on a species to procure resources that are not essential, because individuals who fail to obtain them will not be at a disadvantage. This goes with the definition of essential. IT also addresses your hesitation about "sufficient dependence" above.
Again, this is a little binary. To you, it seems, either our ancestors were "fully aquatic" (and hence you can safely reject the notion) or they were "fully terrestrial" in which case there is no "aquatic ape theory" to deal with. Can you not conceive of something in between? Derek Ellis could. Seen in this light, there might have been a waterside dwelling hominin that relied on the littoral food chain to a large degree but, clearly, that was also very much capable of living on land too. They did MORE wading than chimp ancestors, MORE swimming and MORE diving - but in no sense were they doing so exclusively. Why are such notions not helpful? Why do you have to do the very straw man thing you accused Elaine Morgan of doing?
John Langdon wrote:JL3: Did they live in the same sort of habitat as chimps and gorillas? We don't know since we have not been able to reconstruct the habitats in sufficient detail for the earliest hominins. In fact, as you know, the fossil record is pretty bleak before australopithecines. Since we do not have a fossil record at all, to speak of, for chimps and gorillas, we don't have any information about the habitat of their ancestors. Since we have not found fossils apes and fossil hominins together, there may well have been a significant habitat separation.
Yves Coppens ("East Side Story") created a scenario in which chimp and human ancestors were stuck on different sides of the Rift and then went their different merry ways. There are problems with the details of his version, but basic premise of a geographic divide seems reasonable if unproven.
I agree that Coppens' idea seems reasonable - even though it's the classic savannah theory really. I actually am not opposed to that. I just think people have forgot about micro habitats. As E Africa got more arid, forests would not turn to grasslands randomly or uniformly, they'd shrink back closer to permanent water courses like rivers and lakes. Our ancestors, no doubt, would shrink back into such refugia too. Hence, paradoxically, the drier it got the closer I see our ancestors depending on waterside niches.
Again.. why not? What's wrong with that?
John Langdon wrote:JL3: I'm not sure I follow you because I think you are deliberately distorting things. I make a distinction between the Savanna Theory (which I previously denied existed and Morgan rightly criticizes) and a savanna setting for evolution. The Theory was an intellectually lazy assumption that merely changing habitats led to the evolution of certain traits. That is very different from an assertion that certain stages of human evolution occurred in a savannah setting and we can construct hypotheses why certain traits emerged in that context. Paleoenvironmental evidence can now link the emergence of Homo to a more open habitat, but older hominins are still associated with a more closed one. We have gotten more cautious (sophisticated?) about stating everything as either or forest or savanna, recognizing that habitats are more complex. I can show you pictures I took in Kenya in 1980 on a savanna showing greatly different levels of tree cover with a few miles of each other. I know of one study site of chimps living on a savanna in West Africa.
I'm not distorting that your JHE paper made the astonishing claim that a 60-70 year long paradigm established in paleoanthropology was, somehow, a straw man invention of Elaine Morgan, John. I'm not distorting that practically every argument you make seems to be a straw man exaggeration yourself and that you seem to be avoiding discussing the fact that many people (on both sides of the 'aquatic' divide) made a very different (and less extreme) assumption about the idea than you did.
As I alluded to above, I think you're right that the savannah is not all open grassland and perhaps in that sense some "aquatic ape" proponents are also guilty of making straw man arguments against it. But please be clear about two things: 1) I (and a few like me) are not doing this and, 2) two wrongs don't make a right. You are every bit as guilty of the 'straw man' thing against the "aquatic ape" as you say Morgan is on the savannah, in my view.
John Langdon wrote:JH3: What trait(s) are you referring to? The two I identified on the chart that way are not present in dolphins:
bipedalism -- Do you have any other examples of aquatic bipeds, aside from penguins that were already bipedal?
speech -- Do you have any other examples of speaking aquatic mammals? (note that was a separate trait from complex vocalizations)
No, of course not. I was just making the point that by stating "not typical of aquatic mammals" the strong implication is that proponents of the idea you were critiquing (or maybe you weren't) think that they were. This is absolutely not the case.
John Langdon wrote:JH3: The traits that really might be compared with dolphins I listed as follows:
breath holding -- primary evidence
complex vocalizations -- parallelism
enlarged pharynx -- primary evidence
respiratory valves -- hypothetical trait
body hair reduction -- part of a thermoregulatory strategy
subcutaneous fat -- part of a thermoregulatory strategy [I would change this now -- I don't see it as part of the human thermoregulatory strategy.]
frontal sex -- secondary to bipedalism
enlarged brain -- parallelism
(By the way, when I described traits as primary evidence, consistent with AAH, or hypothetical, I was trying to infer Morgan's use of the trait.)
If you don't want to use cetacean models for your version of the WHHE, than there is no comparative anatomical support for including complex vocalizations, enlarged pharynx, hair reduction, fat, or enlarged brain as evidence for your model. This is exactly why I asked you to spell out which traits you think your WHHE explains and the evidence for that is. I don't think the WHHE can be as strong as the AAH without the cetacean analogies
I think this is a misconception. Hardy (and Morgan still does) believed a kind of "U-turn" hypothesis. It's a little vague, of course, but the idea was that our ancestors started out on the path towards becoming aquatic, and then turned back. This is not suggesting that humans ever actually became anywhere near as aquatic as them. The body hair loss is a pointer. As Morris put it - where else in Mammalia has evolution favoured the loss of a pelt. It does not necessarily mean that in order to do so we'd have had to have become full on "aquatic" mammals. The Sharp & Costil studies showed that shaving even slight amounts of body hair off men significantly reduced drag.
John Langdon wrote:JH3: You listed 6 specific traits (I will overlook "pretty much all of them".) Again, to avoid putting Morgan's words in your mouth, what are your hypotheses for how/why those traits evolved and your arguments supporting the hypotheses?
From your paper I assume your bipedalism hypothesis is that our ancestors (which and when?) found it necessary to wade (for foraging?) and that bipedal locomotion increased their efficiency in doing so. Is that correct? (If so, is that really better than "they found it necessary to forage more on the ground and since they were poor quadrupeds increased their efficiency by being bipedal?")
How about the others? I would like to see them all so I can get a better understanding of how you reconstruct our ancestors and their relationship to water. But I also don't think they will make a coherent model.
In a nutshell...
Bipedal origins through wading/climbing very early (pre- LCA). Since the split, Pan/Gorilla climbed more, waded less - reverted to the large primate 'norm' of quadruepdalism on land. Human ancestors climbed less, waded more - became obligate bipeds.
Human body hair pattern - as an adaptation to reduce drag whilst swimming (usually face down looking for food) in coastal shallows.
Infant (and mother) adipocity - to reduce the risk of drowning in coastal shallows.
Respiratory changes (all of them - e.g. hooded nose, descended larynx, improved voluntary breath control) as simple adaptations for better swimming and diving.
I call my model "River Apes... Coastal People". Seasonal flooded gallery forests in a broad savannah context (a la East Side Story) followed by a move to coasts (Rift Valley lakes at first but Indian ocean later). This is deliberately very compatible with the fossil record and many other published ideas, notably Coppens and Kingdon. I have always sought to look for common ground between these ideas, and depolarise the debate but as Elaine told me once - trying to middle of the road leads to the risk of getting stones thrown at you from both sides! True words - I seem to have upset both sides simulataneously!
John Langdon wrote:JL3: Honestly, I have not reread that volume since I wrote my paper 15 years ago. I don't own a copy, but obtained it at the time from interlibrary loan. I don't remember them enough to comment. I will not argue that they may have a different take, but what is your point? You stated that Groves argued it would be unfair for me to pick and choose among different authors to critique. I agreed and I didn't. I never pretended to discuss all models. (That didn't stop Morgan from trying to generalize about all terrestrial models under the distortion "Savannah Theory.")
No, I argued that Groves comment in his Roede et al review should have led to critics like you to have consider a milder interpretation of Hardy/Morgan's idea.
Roede et al presented several well written, scientific accounts - mainly of the Hardy/Morgan model, as well as a few others. That you did not cite any findings or opinions from that work makes your paper, in my view, remarkably unscholarly. I suspect that Leslie Aiello and the rest of the editors at JHE desperately wanted to get something published to "kill" this damned idea and you got the ticket. They seem to have lowered the bar and turned off their usual high levels of critical thinking to let it pass through peer review. I note that Elaine's reply was simply rejected.
It just isn't the way science is supposed to be done, John. It was shoddy. Let's raise the bar moving forward, please.
All the best, anyway. I am very much enjoying having this discussion with you. Thanks.