tag:blogger.com,1999:blog-37148773.post6589322430484985144..comments2024-03-19T00:24:23.577-04:00Comments on <center>Sandwalk</center>: Dennett on AdaptationismLarry Moranhttp://www.blogger.com/profile/05756598746605455848noreply@blogger.comBlogger75125tag:blogger.com,1999:blog-37148773.post-46177925530826079472014-01-21T19:53:51.876-05:002014-01-21T19:53:51.876-05:00"aquatic ape just-so story"??
I agree &..."aquatic ape just-so story"?? <br />I agree "aquatic ape" is inaccurate, "ape" should be "Homo" and "littoral" is more precise then "aquatic", but the "littoral theory" appears to be correct: early-Pleistocene Homo did not run over open plains as the conservative story wants, but simply followed coasts & rivers. This didn't happen in 5 or 10 Ma, as Elaine Morgan thought, but in the Pleistocene.<br />Human Evolution publishes in 2 special editions the proceedings of the symposium with Don Johanson & David Attenborough on human waterside evolution "Human Evolution: Past, Present & Future" in London 8-10 May 2013:<br />Special Edition Part 1 (end 2013)<br />- Peter Rhys-Evans: Introduction<br />- Stephen Oppenheimer: Human's Association with Water Bodies: the 'Exaggerated Diving Reflex' and its Relationship with the Evolutionary Allometry of Human Pelvic and Brain Sizes<br />- JH Langdon: Human Ecological Breadth: Why Neither Savanna nor Aquatic Hypotheses can Hold Water<br />- Stephen Munro: Endurance Running versus Underwater Foraging: an Anatomical and Palaeoecological Perspective<br />- Algis Kuliukas: Wading Hypotheses of the Origin of Human Bipedalism<br />- Marc Verhaegen: The Aquatic Ape Evolves: Common Misconceptions and Unproven Assumptions about the So-Called Aquatic Ape Hypothesis<br />- CL Broadhurst & Michael Crawford: The Epigenetic Emergence of Culture at the Coastline: Interaction of Genes, Nutrition, Environment and Demography<br />Special Edition Part 2 (begin 2014) with 12 contributions.<br />FYI, google<br />-econiche Homo<br />-Greg Laden misconceptions Verhaegen<br />-Vaneechoutte Rhys Evans<br /><br /><br />Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-44540129550462452522009-10-01T12:23:53.788-04:002009-10-01T12:23:53.788-04:00"If the hairlessness of the foetal ape was be..."If the hairlessness of the foetal ape was being retained into<br />adulthood by a process of neoteny, one would expect the<br />human body to retain this characteristic throughout its<br />whole development from embryo to adult. However, this is<br />not the case. When the human foetus is 6 months old, it<br />becomes completely covered with a coat of fine hair known<br />as lanugo. Normally, this hair is shed long before birth;<br />occasionally, a baby is born still wearing its woolly coat,<br />only to lose it within the first days after birth (Morgan,<br />1982).<br />Another weakness of the theory is that while some<br />characteristics may be retained as part of a neotenic package,<br />this only applies to characteristics that are either benign<br />or neutral in their effect on fitness to survive. No one claims<br />that all foetal characteristics are retained in a neotenic<br />species. For example, a human foetus and a human baby<br />both have very short bandy legs, but natural selection<br />ensures that this feature is not retained in adult life (Morgan,<br />1990). Furthermore, the neoteny theory does not tell us<br />anything about the value of nudity as a new character that<br />helped the naked ape to survive better in his hostile environment<br />(Morris, 1967)." Rantala, 2007Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-2406364817533584462007-09-15T12:37:00.000-04:002007-09-15T12:37:00.000-04:00Dears,Could you please tell me if the "founder eff...Dears,<BR/><BR/>Could you please tell me if the "founder effect" (= population bootlenecks?) can preserve non-adaptative features?<BR/><BR/>If so, in this case, it would be interesting separate the concept of fitness from the usual definition (fitness = frequency in the population at generation t+1 divided by frequency in the population at generation t.<BR/><BR/>That is, I would like to be able to say that a low fitness gene are preserved and propagated due to a founder effect. Is this correct?Osame Kinouchihttps://www.blogger.com/profile/08477731040936154694noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-32149084457178034282007-09-03T18:41:00.000-04:002007-09-03T18:41:00.000-04:00But, I bet I'm right....I think I have read elsewh...But, I bet I'm right....I think I have read elsewhere more recently too...A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-24349137687356880942007-09-03T18:37:00.000-04:002007-09-03T18:37:00.000-04:00I guess I must have read it years ago in "ontogeny...I guess I must have read it years ago in "ontogeny and phylogeny", but I dont have it with. If anyone can look it up he may correct me if I am wrong or misunderstood something. I have at least remembered restriction to the head accurately, which is the bit relevant to our discussion.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-51473969395792903032007-09-03T16:50:00.000-04:002007-09-03T16:50:00.000-04:00Sanders says: "Chimpanzee fetuses have hair on the...Sanders says: "Chimpanzee fetuses have hair on the head, armpits and genitals only."<BR/><BR/>Like Sven I can't find anything in the literature about this, but I'm not an anatomist so I may be looking in the wrong place. Chimp fetuses do indeed develop hair on their heads, but <I>armpits and genitals</I>?<BR/><BR/>Sanders, could you please supply a reference for your claim.Tony Jacksonhttps://www.blogger.com/profile/09084425003252586913noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-10243545518609150602007-09-03T16:21:00.000-04:002007-09-03T16:21:00.000-04:00"But then, I study organisms, not sequences or roc..."But then, I study organisms, not sequences or rocks"<BR/><BR/>You mean you study ONLY organisms: no sequences or rocks.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-77955334014079452552007-09-03T16:08:00.000-04:002007-09-03T16:08:00.000-04:00JEeez!! Calm down, buddy. There is too much anti-s...JEeez!! Calm down, buddy. There is too much anti-structuralist resentment there to answer; you are not talking to ME, that's clear. I never said adaptaion does not exist, I never said adaptive hypotheses are intrisically silly or speculative. We all agree on the importance of adaptation. <BR/>Plus, quite honestly, I think you are making a little bit of a chauvinsitic fool of yourself. <BR/><BR/>What we don't agree, quite plainly, is that you backwardly think that adaptation=shaped by selection.<BR/>And all i did was to ask you for an example where a new trait has clearly been shaped by the accumulative effect of directional natural selection. <BR/><BR/>I'd even be happy with an example where there is yet no molecular resolution. Orr says the cases proposed by Dozhansky, Huxley, etc are in retrospective "apallingly weak". I want to know if I agree, but I juts haven't found where these authors refer to these cases... <BR/><BR/>But then, Sven,,...are you really understanding what we are talking about here?<BR/><BR/>One has to wonder...A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-71169882417170740602007-09-03T15:28:00.000-04:002007-09-03T15:28:00.000-04:00I should probably should let this be a sleeping do...I should probably should let this be a sleeping dog, but I want to make (or re-make) a couple of points, if only because sanders has been such a dick about it.<BR/>a) Whether a trait (say, the hairiness of human bodies) originates by many small mutations, each one favored by selection (I <I>think</I> this is what is meant by "shaped by selection," but I'm not sure..not because I don't want to understand but because the phrase keeps getting used without definition or explanation), or, alternatively, by a single mutation of large effect (e.g., "full-blown" pedomorphosis) makes <I>absolutely no difference</I> in terms of whether or not it should be considered an "adaptation." Therefore this: "<I>any one-step origin of an adaptation (which are wel-documented) cannot be said to be the result of directional selection</I>" is just plain Wrong. To argue otherwise is to ignore a huge literature on the concept of adaptation (e.g., Rose & Lauder (eds.), 1996, <I>Adaptation</I>; G.C. Williams's books). <BR/>Again: Tinbergen's four questions...there's four of them, see, because they're <I>different questions</I>.<BR/>2. It still seems to me that explaining a phenotype as resulting from drift, or developmental constraint, or heterochrony, or whatever makes pluralists more happy, carries at <I>least</I> the same burden of proof as attributing it to selection.<BR/>3. Any hypothesis of origin and/or maintenance of a particular phenotypic trait is legitimate if it can be tested, even "silly just-so stories." And you know what? it's OK to suggest hypotheses even without testing them right away, and even if testing them would be difficult or impossible, <I>if they are stated as hypotheses</I>. The naive adaptationism that suggests a possible adaptive value to a trait and then considers the matter closed and settled is indefensible, but so, equally, is an argument like "oh, it seems likely to be neotenic so no adaptive explanation is necessary," and leaving it at that.<BR/>4. Read G.C. Williams. He makes the point that the adaptationist program applied to (fixed) phenotypes of extant populations is about maintenance of the phenotype in the face of ongoing mutation, geneflow, and drift, <I>not</I> so much telling tales of evolutionary <I>origins</I>; thus, modern adaptationism is more about explaining the <I>absence</I> of evolution.<BR/>5. Related to the above, "neoteny" is not a sufficient explanation for the persistence of human hairlessness. Neoteny plus fitness-neutrality plus drift would be; neoteny plus population bottleneck would be; neoteny plus selection would be. <BR/>Open any comparative physiology text and learn about the effect of pelage on mammalian energy budgets and the third explanation emerges as the most likely. It really does.<BR/>6. Adaptation is empirical. There really are a gazilliion examples of phenotype/environment matching which even the most ardent pluralist would be foolish not to accept as adaptations. I therefore repeat: in a world of nails, why insist on trying screwdrivers, reciprocal saws, and jackhammers before reaching for the trusty hammer? This attitude I just don't get. But then, I study organisms, not sequences or rocks.<BR/>7. I am unable to find any reference to the presence of pubic and axillary hair in chimp fetuses, only that (as in humans) the hair on top of the head is the first to begin growing. I'd be interested if anyone knows of such. In the meantime I'll continue to regard the Gould quote as stupid (in that regard).<BR/>8. Geographic differences in relative body-hairiness among humans, combined with the marked sexual dimorphism within all populations, are strong clues that sexual selection was involved somehow in the origin and/or maintenance of the hairless phenotype. This is by no means mutually exclusive with natural selection (for running, antiparasitism, or whatever), and not even exclusive with an (otherwise) neutral/drift scenario (which I doubt for other reasons, above).<BR/>And now I really will shut up...classes start Tuesday and there is much work to be done.<BR/><BR/>p.s. re: "<I>there is no example that I know of where an adaptation has been shown to be have been shaped by and accumulation of several gnes by natural selection.</I>" <BR/>Very "pluralistic" of you.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-5376165777890863392007-09-03T14:45:00.000-04:002007-09-03T14:45:00.000-04:00""Full blown" refers to the generic hairy scalp-de...""Full blown" refers to the generic hairy scalp-denuded body pattern, not is precise manifestation today. Hence there is room for modification"<BR/><BR/>Pfffft. I hope you realize It's pretty annoying to discuss with you acting like this. That pattern is the adpataion we are discussing. Period. Don't try moving goalpoasts again like that, it is very non-elegant.<BR/><BR/>Human skin evolution has painfully few sources of information; but uite beyond this specific case, I bring to your attention once more that any one-step origin of an adaptation (which are wel-documented) cannot be said to be the result of directional selection. This is no divagation of mine: it is the CLASSICAL antidarwinian argument of the mutaionists: De Vries, Bateson, Goldschmidt. And it's alive and kicking. All of them emphasized development.<BR/><BR/>Anybody should understand this point clearly. When adaptaionists say they don't understand, they seem to me simply unwilling to understand. <BR/><BR/>I wih you luck too in your future reserach, I think you will be needing it because the study of the origin of adaptaions in the wild and in experimental evolution, where genes are studied at the molecular level of resolution, has shown few mutations with large effect are behing the origin of new adaptations. In fact, there is no example that I know of where an adaptation has been shown to be have been shaped by and accumulation of several gnes by natural selection.<BR/><BR/>If you have any such case, please present it.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-54511344132140057602007-09-03T13:23:00.000-04:002007-09-03T13:23:00.000-04:00I hit the wrong button and published prematurely.S...I hit the wrong button and published prematurely.<BR/><BR/>Sanders: "It appeared before running in the sun, as the chimpanzee fetus shows."<BR/><BR/>That's right - in the FETAL stage, not the adult.<BR/><BR/>Sanders: "How is it reinforced and modified by selection if it had emerged "full blown"?" <BR/><BR/>Are you prepared to argue that the human adult hair distribution pattern has complete fidelity to the chimp fetal pattern? That there has not been the slightest developmental modification? ("Full blown" refers to the generic hairy scalp-denuded body pattern, not is precise manifestation today. Hence there is room for modification.)<BR/><BR/>Sanders: "...does not allow a reduction only to the selective component."<BR/>"...on what the importance of things other than "current use" can have in the origin of adaptations."<BR/><BR/>One more time (with new emphases):<BR/><BR/>Me, earlier post: "Selection acts on variants of DEVELOPMENTAL programs that have been shaped over their phylogenetic histories by a VARIETY of evolutionary forces."<BR/><BR/>There is little point in us continuing this argument. We have acknowledged our respective differences and similarities on this topic. (Except where you insist on seeing differences where none exist.)<BR/><BR/>We're all adaptationists and we're all pluralists. Me, you, Larry Moran, Richard Dawkins, Richard Lewontin, Stuart Kauffman. Sure, we have different emphases, different perspectives. On a conciliatory note, let me suggest that the existence of multiple approaches is conducive to the advancement of evolutionary science, and not a pathological rift.<BR/><BR/>Despite misunderstandings, you've made some cogent points, as well as some that are perhaps less well considered. Anyway, I wish for the success of your endeavors. <BR/><BR/>- "Anonymous"Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-41688097979546242942007-09-03T12:45:00.000-04:002007-09-03T12:45:00.000-04:00Sanders: "It appeared before running in the sun, a...Sanders: "It appeared before running in the sun, as the chimpanzee fetus shows."Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-15342104073244416802007-09-03T12:33:00.000-04:002007-09-03T12:33:00.000-04:00In a topic like this, where any source of informat...In a topic like this, where any source of information is of great value, I find it revealing that one of the few compelling pieces of data that is available becomes inevitably downplayed by an adaptationist viewpoint. <BR/><BR/>"You're speculating that the pedomorphic hair distribution pattern appeared first (as a developmentally constrained side effect of another process?) and it was permissive for "run in the sun." <BR/><BR/>It appeared before running in the sun, as the chimpanzee fetus shows. Why do you call this a speculation? The organism was capable of producing this hair pattern long before running in the sun.<BR/>Whe the trait appeard in the adult, running may have already being in place, but it may have perfectly well not, either. We don't know. However I think that there is no way that acquiring that pattern in the adult did not radically improve the running in the sun, opening a wider range of behavioral possibilities. <BR/><BR/>Anyhow, it is good that you acknowledge that there is a feedback between behaviour and selection; maybe you will see that this cyclical dynamic of interactions between behaviour, trait and selection does not allow a reduction only to the selective component.<BR/>I wonder why did you not mention development though. It is not putty, you know. <BR/><BR/>"Selection for general hairlessness would act on the developmental pathway of body hair emergence and so produce a pedomorphic distribution pattern, (unless there were selection for total hairlessness, which obviously there wasn't)"<BR/><BR/>But selection would not affect the establishment of the hair pattern, but merely delay the presence of that pattern into the adult. It would be a "timing" mutation: not a "patterning" one. <BR/><BR/>I am trying to use this example to make you reflect on what the importance of things other than "current use" can have in the origin of adaptations. Do you really think without this preexisting fetal pattern humans would have anyhow evolved running in the sun? Well, I guess that there is where we can draw a clear line between our views.<BR/><BR/>"and hence the pedomorphic hair distribution pattern (whether it emerges gradually or full blown) undergoes positive selection and is reinforced and modified"<BR/><BR/>How is it reinforced and modified by selection if it had emerged "full blown"? Face it; if an adaptive trait emerges full-blown, selection can maintain it but has little to do with its origin. This origin will have a much more to do with developmental possibilities than with the result of directional selection.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-76615302246513026182007-09-03T03:43:00.000-04:002007-09-03T03:43:00.000-04:00Sanders: "But the hair distribution pattern is a p...Sanders: "But the hair distribution pattern is a pretty straightforward neotenic trait."<BR/><BR/>I agree that it is an apparently pedomorphic trait. <BR/><BR/>To quote myself:<BR/><BR/>"Selection acts on variants of developmental programs that have been shaped over their phylogenetic histories by a variety of evolutionary forces."<BR/><BR/>Just to make sure that we are on the same page: You're speculating that the pedomorphic hair distribution pattern appeared first (as a developmentally constrained side effect of another process?) and it was permissive for "run in the sun." <BR/><BR/>In contrast, in my model, the "run in the sun" behavior emerges first, which results in selection for hair loss - and hence the pedomorphic hair distribution pattern (whether it emerges gradually or full blown) undergoes positive selection and is reinforced and modified. Selection for general hairlessness would act on the developmental pathway of body hair emergence and so produce a pedomorphic distribution pattern, (unless there were selection for total hairlessness, which obviously there wasn't). <BR/><BR/>Example of modification: ever-growing head hair.<BR/>http://mednews.wustl.edu/tips/page/normal/4405.html<BR/><BR/>(It's conceptually possible that the chimpanzee fetal hair distribution pattern is a spurious non-homologous similarity and the adult human hair pattern arose independently through the strong selective advantage of having thick head hair on a mostly denuded body. But I doubt it. It's far more plausible - and parsimonious - that selection made use of a preexisting developmental program.)<BR/><BR/>The facilitating effect of the hairlessness with its (pedomorphic) distribution, along with the rest of the functional trait complex (anatomical, physiological) on "run in the sun" behavior provided a positive feedback loop of behavior, selection, and trait complex.<BR/><BR/>Note that acknowledging the pedomorphic nature of hair distribution does not in any way constitute an endorsement of Gould's epiphenomenal global neotenization model. <BR/><BR/>We agree that heterochrony can be highly modularized.<BR/><BR/>Another hypothesis for hairlessness: defense against ectoparasites <BR/>http://tinyurl.com/2vvfal<BR/><BR/>Maybe the actual scenario was more complex than current models and included multiple selective forces acting on differentially developmentally linked traits (hormone activity etc.), perhaps even involving genetic assimilation. I am not personally invested in any particular model.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-35327522980061282652007-09-03T01:47:00.000-04:002007-09-03T01:47:00.000-04:00I have been hearing about these hot-running ape hy...I have been hearing about these hot-running ape hypotheses for years now, in relation to bipedism, AND the distribution of hair. I completely agree that this hair distribution can be good for running in the sun. I have not once called this a bad speculation or a just-so-story. I stated at the beggining of this thread that I object to the "just so story" pejorative because it's unspecific and unfair.<BR/><BR/>But the hair distribution pattern is a pretty straightforward neotenic trait. A I said, this was already present in the fetus, long before sun-running. If you ask me, the neoteny of this trait helped make "run in the sun" possible. In THAT order, OK? THAT is what is consistent with the datum of the chimpanzee fetus, a truly integrative approach to ALL the information. <BR/><BR/>But for an adapataionists, current adapative advatages of this hair diostribution for sun-running contain in thmesleves the evolutionary explanation for its origin. Moreover you have expressed your preference for a gradualist scenario of directional selection as "more likely",you actually mean the fetal pattern could well have not existed: that it has no true importance.<BR/><BR/>If you do not think this, I think the burden is on you to PLEASE explain to us HOW do you think the chimpanzee fetal pattern was relevant at all for the origin of this adaptation.<BR/><BR/>Because right now, you seem to be pushing this datum off the table. Being speculative withotu much evidence is not so bad; denying the relevance of data that is dangling in front of your eyes..,. well that's the kind of silly thing only intellectual alienation can achieve.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-32046782269904084282007-09-02T20:16:00.000-04:002007-09-02T20:16:00.000-04:00There is an older study that photgraphed bipedal m...There is an older study that photgraphed bipedal models form different sun-angles, measured the areas "exposed" in each photgraph and concluded that the head was most exposed and related this to hair distribution.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-6663705257887453032007-09-02T19:50:00.000-04:002007-09-02T19:50:00.000-04:00Sanders, show me where in "Endurance running and t...Sanders, show me where in "Endurance running and the evolution of Homo" by Bramble and Lieberman (Nature. 432:345-352. 2004.) they bring up scalp hair. ("Cranial cooling systems" refers to cranial venous circulation.)<BR/><BR/>And look which notorious ultra-adaptationist provisionally accepted the Lieberman-Bramble hypothesis as worthwhile and not a candidate for immediate dismissal as one of those baseless just-so stories.<BR/>http://pharyngula.org/index/weblog/comments/marathon_man/<BR/><BR/>At least Sanders has done us the service of demonstrating that snideness is no substitute for argumentation.<BR/><BR/>The post started out with, and much of the thread has followed, a contrast between the allegedly sophisticated global neoteny epiphenomenal hypothesis of human hairlessless and the allegedly naive 'just-so story' of endurance running. At this point in the thread, how many of you think the former is much more scientifically rigorous and supportable than the latter? At the very least, how many think at this point that the running hypothesis ought to be dismissed out of hand?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-51768814561501438642007-09-02T19:47:00.000-04:002007-09-02T19:47:00.000-04:00"I confess I do not understand the difference bein..."I confess I do not understand the difference being drawn between "shaped by selection" and...whatever the alternative is supposed to be"<BR/><BR/>yeah...well make it pretty clear that you don't really care about understanding.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-9422221323901403552007-09-02T19:23:00.000-04:002007-09-02T19:23:00.000-04:00I think a substantial part, if not the majority, ...I think a substantial part, if not the majority, of paleo people, biochemists etc. are adaptationists. let's face it, it's pretty easy to understand, kinda a default condition. <BR/>If objectors arise more notoriously in paleo or biochemical fields, gee, I don't know..maybe we just have greater intellectual diversity than the typical row of "darwinian ecologists". <BR/>But of course there also are "neutralists" ecologists too like Hubbell, S. P. (2001). "The unified neutral theory of biodiversity and biogeography." <BR/><BR/>Anyway, it intrigues me that ALWAYS adaptaionists come u with tehse frivolous, silly, gossipy arguments. Guys, only reatrds will buy that crap. You know, people who will be willing to judge on appereances rather than true arguments.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-71753941696747882292007-09-02T18:53:00.000-04:002007-09-02T18:53:00.000-04:00ha, I thought you KNEW it, but you don't. The "run...ha, I thought you KNEW it, but you don't. The "run in the sun" hypothesis emphasizes how having hair on the top of the head, but not on the rest of the body, is ideal to prevt solar radiation at the head, while allowing the rest of the body to lose heat.<BR/>IYet you try to pretend that you are discussing completely unrelated trait...well that's just stupid.<BR/><BR/>Other than that you can make as many non-biological and frivolous "closing statements" about pluralists and adaptationists as you wish. Come back when you have something truly interesting.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-9863764552214457612007-09-02T18:31:00.000-04:002007-09-02T18:31:00.000-04:00sanders: "that attributes this pattern to selectio...sanders: "that attributes this pattern to selection"<BR/><BR/>No, I attributed relative hairlessness, not the spatial distribution of hair, to selection. Reread my comments.<BR/><BR/>Based on the above and other remarks, I have to conclude that the main issue here is your repeated misinterpretation of my statements, for whatever reason.<BR/><BR/>The problem with many pluralists (structuralists, Gouldians, whatever they want to call themselves) is that they believe they are exhibiting sophistication simply by hand-waving about developmental constraints, bricolage, systems theory, exaptations, L-systems etc. Rest assured that we adaptationists are aware of these things as well. I daresay that modern adaptationists tend to have a more sophisticated understanding of the interplay of these phenomena with selection and other evolutionary forces (yes, Dr. Moran, including drift) to shape organismal form and function.<BR/><BR/>Too many pluralists fail to understand that some of their favored default nonadaptationist assumptions are no less fanciful and unsupported than some adaptationist ones. All hypotheses have to be subjected to testing.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-57676782226503902872007-09-02T17:16:00.000-04:002007-09-02T17:16:00.000-04:00You take the fetal pattern lightly. Have I ever ru...You take the fetal pattern lightly. Have I ever ruled out the possibility that this hair pattern is adaptive for humans as in the "run in the sun hypothesis"? <BR/>You fail to recognize that "adaptive for running in the sun" is not equivalent to "shaped by selection for running in the sun". The hair pattern apeared in the fetus, and thereafter in adult, making "run in the sun" suddenly possible. <BR/><BR/>You gradualist scenario that attributes this pattern to selection would indeed imply that the fetal pattern is nothing but a coincidence. <BR/><BR/>If you do not understand this...there is little hope.<BR/><BR/>I would not call ANY trait with an effect on fitness an "adaptation".I think most people understand that for a trait to be adaptation it must have a positive effect on fitness; that is, a novelty that is favored by selection, not eliminated by it as in the cases you propose. I think you've got it all quite wrong.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-71693865850300365002007-09-02T16:57:00.000-04:002007-09-02T16:57:00.000-04:00This comment has been removed by the author.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-69673768846260663692007-09-02T15:03:00.000-04:002007-09-02T15:03:00.000-04:00sanders: "we all have eyes and eyes do not determi...sanders: "we all have eyes and eyes do not determine fitness differences."<BR/><BR/>Do you wish to argue that there is no such thing as congenital blindness (or more narrowly, genetically determined congenital absence of eyes)? And that this has no effect on fitness?<BR/><BR/>"you imply the fact this trait is preshaped in the chimpanzee fetus is just a bizarre coincidence." <BR/><BR/>This is a strange misinterpretation of my views.<BR/><BR/>As Sven DiMilo suggested, review what Tinbergen wrote about the "four questions," in order to avoid the elementary mistake of conflating levels of explanation and hence erroneously concluding that they are mutually exclusive.<BR/>http://en.wikipedia.org/wiki/Tinbergen%27s_four_questions<BR/><BR/>Also see:<BR/><BR/>Gerhart, J and M Kirschner. 1997. Cells, Embryos, and Evolution.<BR/><BR/>Gilbert, SF. 2001. Ecological developmental biology. Developmental Biology. 233:1-12.<BR/><BR/>Pigliucci, M and J Kaplan. 2000. The fall and rise of Dr Pangloss: adaptationism and the Spandrels paper 20 years later. Trends in Evolution & Ecology. 15:66-70<BR/><BR/>Williams, GC. 1992. Natural Selection: Domains, Levels, and Challenges.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-30759949952887628292007-09-02T14:52:00.000-04:002007-09-02T14:52:00.000-04:00Divalent says,You know, I think I’ve discovered th...Divalent says,<BR/><BR/><I>You know, I think I’ve discovered the core of your argument: there are some things that *you* have decided are not (politically) "correct" and that should not be studied. But instead of being upfront about it, you are *framing* this issue as being about the proper methodological approach that should be employed when doing science.</I><BR/><BR/>We're not going to get very far in this discussion if you keep trying to put words in my mouth. <BR/><BR/>I have never, ever, said that there are things that shouldn't be studied. I have argued in the past that we should study many things that are not "politically correct." Please don't make that statement again or this discussion is ended.<BR/><BR/>What I've said is close to the second part of your sentence. I have an strong opinion about how things should be studied and I have a strong opinion about how evolution occurs. In my opinion it is not good science to assume your mechanism (natural selection) when developing explanations for a given feature. The very first question you need to ask is whether the feature is an adaptation. If you decide to rule out all other possible mechanisms of evolution then you should explain how you arrived at this conclusion. When you jump right into an adaptationist just-so story you are revealing a bias. You might also be revealing a lack of knowledge of how evolution really works.<BR/><BR/>With regard to the word "framing," I think you know that to me framing is just another word for "spin." Spin is something you do deliberately in order to twist the argument in a certan direction. When you "spin" something you are making a conscious effort to deceive or mislead.<BR/><BR/>I don't spin and I don't frame. You may not like what I'm saying but at least accord me the courtesy of accepting that I'm sincere about it. I accept that you are sincere about defending the adaptationist program and I don't insult you by attributing ulterior non-scientific motives.<BR/><BR/><I>It leads you to ridicule a scientist over a non-controversial issue (Dr. Hotopp) for proposing a hypothesis that will lead her or others to investigate further.</I><BR/><BR/>Her "hypothesis" is that the extra DNA <B>must</B> be an adaptation. That doesn't sound like a question to be. It sounds like her mind is already made up. A scientifically correct hypothesis would be something like: "I propose that the extra DNA confers some fitness advantage on the individuals that possess it."Larry Moranhttps://www.blogger.com/profile/05756598746605455848noreply@blogger.com