tag:blogger.com,1999:blog-1812431336777691886.post6682389397296913397..comments2024-02-29T03:57:00.088-05:00Comments on The Mermaid's Tale: With great power there must also come great responsibilityAnne Buchananhttp://www.blogger.com/profile/09212151396672651221noreply@blogger.comBlogger22125tag:blogger.com,1999:blog-1812431336777691886.post-23278871643387031192010-04-27T17:21:03.022-04:002010-04-27T17:21:03.022-04:00Oops, I meant to say, "in paleontology, cladi...Oops, I meant to say, "in paleontology, cladists never assign more than one species to any given [extinct] genus." There's no problem with classifying more than one paleontological species in an extant genus such as <i>Homo.</i>James Goetzhttps://www.blogger.com/profile/02412501436355228925noreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-944646050919849742010-04-27T16:54:38.992-04:002010-04-27T16:54:38.992-04:00Yes, Ken, you're correct about hypothetical ti...Yes, Ken, you're correct about hypothetical time travel and the biological species concept.:) I misrepresented cladistics, but in paleontology, cladists never assign more than one species to any given genus. And they say that we can never know for sure if any given fossil represents a specimen from an ancestral lineage of any given species. For example, paleontologists can estimate that a given fossil belonged to either A) an ancestral population or B) a closely related ancestral population. But they never know for sure that it's A or B.James Goetzhttps://www.blogger.com/profile/02412501436355228925noreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-85942826933434013382010-04-26T17:45:11.080-04:002010-04-26T17:45:11.080-04:00Precisely, and that's why Tim White has opined...Precisely, and that's why Tim White has opined that sediba is "just" a chronospecies of africanus. The quest to find the magic synapomorphy that links sediba or any other australopith uneqivocally to Homo (however you wish to define the earliest version) strikes me as a tad quixotic. Playing the Homo hand is always good for headlines, however.occamserasernoreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-47656395577586248102010-04-26T16:34:45.508-04:002010-04-26T16:34:45.508-04:00Your tuppence are always welcome, Jim.
I'm no...Your tuppence are always welcome, Jim. <br />I'm not a cladist, and good ol' Holly will have to respond to that part of your comment, if she has anything to say. <br /><br />I'd add that even without splitting into divergent lineages, the idea is that over time even within a lineage there is enough change that, were the ancestral and descendant individuals to be alive at the same time -- a counter-factual thought experiment, I know -- they would be reproductively incompatible and would be called separate species. <br /><br />Give it enough time and they would be different enough to be said to be in different genera, though I agree that's an arbitrary, human-imposed distinction.Ken Weisshttps://www.blogger.com/profile/02049713123559138421noreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-5631058422319699652010-04-26T16:28:08.889-04:002010-04-26T16:28:08.889-04:00May I add my two cents about paleontological taxon...May I add my two cents about paleontological taxonomy? Cladists must fight against the classification of another <i>Australopithecus</i> species. Moreover, cladists must assign a new genus to all but one <i>Australopithecus</i> species or some people might get confused and think that a species could be ancestral to another species, or that a genus could be ancestral to another genus, and other such madness.:)James Goetzhttps://www.blogger.com/profile/02412501436355228925noreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-58175761443702467662010-04-26T14:03:20.380-04:002010-04-26T14:03:20.380-04:00Awesome. And about the last part... me too, actual...Awesome. And about the last part... me too, actually. Ha!Holly Dunsworthhttps://www.blogger.com/profile/05260104967932801186noreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-39266876438244084702010-04-26T13:51:00.540-04:002010-04-26T13:51:00.540-04:00Just trying to add to the discussion. No offense i...Just trying to add to the discussion. No offense intended, just thought some facts and related speculations might be interesting and perhaps useful in a "comments" section. <br /><br />I suspect the KW debate will continue for a while, and that's a good thing. KWing is such a peculiar way of moving quadrupedally; it's hard to imagine the degree of parallelism and number of homoplastic details required for its supposed independent development in African apes. That darn os centrale ...<br /><br />Yep, hard to judge overall arm length without a standard, like relative to lower limb length or even trunk length. But the high brachial index is pretty interesting in its own right and confirms prior inferences based on fragmentary data that australopiths were not like humans in this regard. The drawings are presumably just the authors' hypothesis. It's funny, however, that Berger and Co. have gone on record as claiming that sediba had "long legs" too. The femoral fragments certainly don't confirm this, and one might wonder if it's just another effort to make sediba more Homo-like (after all, it's not important unless it's the sister group of humans, right?? <---- feeble attempt at irony).<br /><br />I'd love to hear more about your take on the Miocene apes and Ardi.occamserasernoreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-20259936460079400392010-04-26T12:24:45.672-04:002010-04-26T12:24:45.672-04:00So much for play. Now I feel compelled to comment ...So much for play. Now I feel compelled to comment just to cover my ath...<br /><br />1. Looking forward to reading the Williams paper.<br /><br />2. Still not willing to conjecture about overall arm length the way that the drawings have.<br /><br />3. Of course it's an old idea. I'm not necessarily supporting it (I was playing), but I sure wouldn't throw out an idea just because it's old or not in vogue. My "ask Ardi" had nothing to do with Ardi's morphology and everything to do with the interpretations made by the authors about Miocene ape evolution in general.Holly Dunsworthhttps://www.blogger.com/profile/05260104967932801186noreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-55697226948323800262010-04-26T11:29:42.752-04:002010-04-26T11:29:42.752-04:00Parallel evolution of KW in Pan and Gorilla is a t...Parallel evolution of KW in Pan and Gorilla is a tough sell, and for good reasons. The Kivell and Schmitt hypothesis of parallel evolution has already been challenged:<br />"Morphological integration and the evolution of knuckle-walking," by SA Williams (J. Human Evol. (2010,in press and available doi:10.1016/j.jhevol.2010.03.005<br /><br />With respect to Au. sediba's "long arms", the FOREARM is indeed long by any human standard; with a brachial index of ~88, it overlaps at the lower end with chimps and bonobos. The femora they published are much too fragmentary to get a reliable humerofemoral index, but the upper limb joints are large relative to the lower ones (a pattern already known for Au. africanus, the likely ancestor of sediba). I'm betting on Lucy-like interlimb proportions.<br /><br />The suggestion that bipedalism is primitive isn't new or very compelling. Pickford and Senut have been trying to sell this idea via Orrorin for ages now. And Ardipithecus is an arboreal quadruped by the describers' own admission; the bipedal signal is weak to absent in my opinion.occamserasernoreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-19777248385542591022010-04-26T11:15:50.610-04:002010-04-26T11:15:50.610-04:00Yes, it was intentional. Otherwise, I could have ...Yes, it was intentional. Otherwise, I could have claimed to be primal, primeval, primate, or even prime number. It's interesting that primates must have been named because somebody thought they were what God made first?Ken Weisshttps://www.blogger.com/profile/02049713123559138421noreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-79856177120360849222010-04-26T10:34:06.024-04:002010-04-26T10:34:06.024-04:00Was "primative" intentional? If not, doe...Was "primative" intentional? If not, doesn't matter... it's a great word! I'm primative too.Holly Dunsworthhttps://www.blogger.com/profile/05260104967932801186noreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-22606593327906664422010-04-26T09:51:32.597-04:002010-04-26T09:51:32.597-04:00Knuckle-walking seems so specific that it's ha...Knuckle-walking seems so specific that it's hard to see independent evolution....except that anyone who has played with their toddlers or pets probably gets down on all fours by knuckle-walking. At least, I know I did (yes, I know I'm primative!). So maybe we never actually gave it up entirely--maybe it's just 'natural' in some sense?Ken Weisshttps://www.blogger.com/profile/02049713123559138421noreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-87862827658213870952010-04-26T09:41:19.191-04:002010-04-26T09:41:19.191-04:00By all recent accounts (Tracy Kivell's work, e...By all recent accounts (Tracy Kivell's work, etc...) gorillas and chimps evolved knucklewalking independently, so it's not necessarily a problem there.Holly Dunsworthhttps://www.blogger.com/profile/05260104967932801186noreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-46407980481905677542010-04-26T09:18:36.418-04:002010-04-26T09:18:36.418-04:00I'll believe that when I see real, convincing ...I'll believe that when I see real, convincing evidence. That would be a problem given the consistently closer genomic hu-ch branch relative to gorillas. Possible, of course, but a kind of reversal from other closely related primates, no?<br /><br />Also would that not imply a 'regression' to other apparently shared traits of primates (big canines, smaller brains and all that). Or would there have been a dull-toothed, somewhat sharp-witted, thumb-sucking, beast around, and its revolted relatives decided to go back to the ways of their ancestors?Ken Weisshttps://www.blogger.com/profile/02049713123559138421noreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-37831941026368007202010-04-26T09:13:51.609-04:002010-04-26T09:13:51.609-04:00Well, just to let you in on a little secret... the...Well, just to let you in on a little secret... there is a very low rumble that dare not be spoken too loudly and it's got something to do with bipedalism being older than the LCA (knucklewalking would be derived in comparison) and if that's the case, then there could be very old bipedal lineages. But you didn't hear that from me. Ask Ardi.Holly Dunsworthhttps://www.blogger.com/profile/05260104967932801186noreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-57973329083426500522010-04-26T09:05:40.695-04:002010-04-26T09:05:40.695-04:00Telling how many branches is rather problematic (a...Telling how many branches is rather problematic (as, for example, Jeff Long's recent work apparently shows about some assertions related to Neandertals).<br /><br />And at least we should realize that genetically they would have been as alike as, say Eskimos, Fuegians, and Khoisan,etc., no?<br /><br />As to Mermaid getting scoops, it's frustrating, since we've not yet started selling full-screen ads. We better hurry....Ken Weisshttps://www.blogger.com/profile/02049713123559138421noreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-52657242353743233192010-04-26T09:03:46.948-04:002010-04-26T09:03:46.948-04:00Ken:
1. No doubt A. sediba was delicious.
2. It&#...Ken: <br />1. No doubt A. sediba was delicious.<br />2. It's important to know if there was more than one branch of bipedal hominins so that's the biggest cause of the "gee-wow" with all new finds that fill in gaps.Holly Dunsworthhttps://www.blogger.com/profile/05260104967932801186noreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-17865862977763077812010-04-26T09:02:07.201-04:002010-04-26T09:02:07.201-04:00JKW... if there are lips at Malapa I will absolute...JKW... if there are lips at Malapa I will absolutely die. The Mermaid's Tale should get first scoop on that, right?Holly Dunsworthhttps://www.blogger.com/profile/05260104967932801186noreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-76335340133646507152010-04-26T08:24:59.557-04:002010-04-26T08:24:59.557-04:00The preservation is so great that there are squish...The preservation is so great that there are squishy parts?! The obvious question (which connects to a previous post) is are there lips? :-)JKWhttps://www.blogger.com/profile/09292737413026824514noreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-22749827682727093772010-04-26T08:23:33.151-04:002010-04-26T08:23:33.151-04:00Unless, of course, they really _would_ be good to ...Unless, of course, they really _would_ be good to barbecue on a nice summer afternoon.....Ken Weisshttps://www.blogger.com/profile/02049713123559138421noreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-29849672609756788962010-04-26T08:22:52.746-04:002010-04-26T08:22:52.746-04:00This is another great, timely, and knowledgeable p...This is another great, timely, and knowledgeable post, Holly! Thanks very much.<br /><br />It's interesting to compare the variation we see in primate or perhaps all vertebrate fossils, with the conservation we discussed in some recent posts. Are vertebrates more variable, and if so, why?<br /><br />Also, since millions of years often separate these isolated fossils, of course they will differ, as you say. And also as you say, the 'names' are ours, not theirs.<br /><br />But is there anything particular to be surprised about with these fossils any longer? Aren't they just filling in space with various kinds of variation, as we'd expect, rather than giving us any fundamentally new picture? Whether the feet were longer than the eyebrow, don't we now have the basic picture?<br /><br />I mean, we don't find any specimens with, say 3 arms or 6 digits, large canines or sharp claws, etc.<br /><br />If the latter is true, then the finds are of course still interesting, but is it time to move beyond "Gee-Wow!"? Except, of course, it sells magazines and television.Ken Weisshttps://www.blogger.com/profile/02049713123559138421noreply@blogger.comtag:blogger.com,1999:blog-1812431336777691886.post-41612583424598371552010-04-26T08:15:52.527-04:002010-04-26T08:15:52.527-04:00Great post, Holly! My favorite lines, among many:...Great post, Holly! My favorite lines, among many: "Malapa is certainly special but clones of previously known hominins? Now THAT would be special."Anne Buchananhttps://www.blogger.com/profile/09212151396672651221noreply@blogger.com