tag:blogger.com,1999:blog-37148773.post452530271090066937..comments2024-03-27T14:50:47.345-04:00Comments on <center>Sandwalk</center>: Jason Rosenhouse Doesn't Understand PluralistsLarry Moranhttp://www.blogger.com/profile/05756598746605455848noreply@blogger.comBlogger8125tag:blogger.com,1999:blog-37148773.post-19191054230127608012009-05-13T15:15:00.000-04:002009-05-13T15:15:00.000-04:00"Adaptation at the population level"
That may hav..."Adaptation at the population level"<br /><br />That may have nothing to do with the origin of biological structures. For instance, the fitness of a population can change with no new phenotypes involved. We're talking about the origin of organic structures here. <br /><br />"show me a case of plasticity that mismatches phenotypes to environments and I'll change my mind"<br /><br />Say we have environmental exposure to a teratogen, and we get several malformations. Not necessarily a "fit to environment" huh.<br /><br />"Most evolution occurs by drift at the genotype level; the conceptual leap to phenotype is dubious"<br /><br />What the hell do you mean? Obviously mutations producing non-adapative phenotypic traits exist. <br /><br />"Complex biological structures may "arise" by drift, but they must be maintained in populations by selection"<br /><br />In any case, selection is insufficient.A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-60968536046175268252009-05-13T14:21:00.000-04:002009-05-13T14:21:00.000-04:00Not much changes around here, I see. Adaptation at...Not much changes around here, I see. Adaptation at the population level is the product of selection, period. Phenotypic plasticity, is itself an adaptation (show me a case of plasticity that mismatches phenotypes to environments and I'll change my mind). Exaptations are structures that acquire a new function; the spread of the new function (and subsequent modifications to the original structure) occurs by selection. Most evolution occurs by drift at the genotype level; the conceptual leap to phenotype is dubious. Complex biological structures may "arise" by drift, but they must be maintained in populations by selection. If there is a cost to making and maintaining them (as is implied in "complex") then they are not "neutral."<br /><br />*shrug* So there's my opinion--it hasn't changed either.Sven DiMilonoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-77919171415892571632009-05-13T11:23:00.000-04:002009-05-13T11:23:00.000-04:00Laurent, Jason gets it, but you don't. This is a q...Laurent, Jason gets it, but you don't. This is a question about whether adaptation rises only by natural selection. Everyone agrees that both adpatiove and non-adpatove traits exist. But when you see and adpataion, is it immediately proof that it is the result of natural selection? (the answer: of course not)A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-15295364852026751752009-05-13T10:23:00.000-04:002009-05-13T10:23:00.000-04:00So, to summarize the debate as I've read it here a...So, to summarize the debate as I've read it here and there:<br /><br />"pluralists" acknowledge that selection is important, but doesn't explain everything.<br /><br />"ultra-selectionists" acknowledge that constraints are important, but don't explain everything.<br /><br />And the point is? Oh yeah, there's a major difference in that each acknowledge many influences over evolution, but that the others disregard their favourite explanation.<br /><br />Eventually, "pluralist" is a poor wording because it implies the others are not, which is simply a strawman.<br /><br />Now, the debate runs alike:<br />"Selectionist": Horns in rhinos were probably selected because it provided a useful defense against enemies, this is adaptive!<br />"Pluralist": You're wrong, two horns or a single one is a developmental constraint because it does not make any difference in fitness.<br />"Ultra-Meist": Hum, and what about sexual selection? Two horns are quite cool, don't you think?<br />"Post-Pluralist": Okay, it just looks like horns are useful as defensive weapons today, in that sense these are possibly developmentally constrained exaptive adaptations, but you know base ball, don't you? It is thus possible that pre-horns in a distant past were used as efficient sexual displays and increased fitness via attractiveness but they are still evolutionary constraints because you know, rhinos don't fly.<br /><br />(Chirping rumours of battle).Laurenthttp://seedsaside.wordpress.com/noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-87185582569570497002009-05-13T00:51:00.000-04:002009-05-13T00:51:00.000-04:00"I've never really understood what it is exactly t..."I've never really understood what it is exactly that anti-selectionists are complaining about. If they agree that complex adapations arise as the result of gradual accretion mediated by natural selection, then I fail to see how they are really so different from people like Richard Dawkins or Daniel Dennett. If they do not agree then I would like to hear their proposed alternative mechanism"<br /><br />Jason is right. So let me be clear about this: I do not agree that adaptations (complex or npn-complex) are mainly the result of natural selection. <br /><br />Phenotypic plasticity and exaptation are two important mechanisms other than selection that are involved in the origin of adaptations (complex, and non-complex). Larry likes to ignore phenotypic plasticty but it is right there in the spandrel's paper that he supposedly has read so deeply. <br /><br />“Certainly natural selection is a compelling explanation for complex structures like bird wings and immune systems"<br /><br />Biologists are not concerned about the "compellingness" but about the scientific usefulness of an explanation. To say "the bird wing is the result of natural selection" is as vacuous a statement as can be made about the evolution of the wing. It is further patently unrealistic, since natural selection is only a fraction of what is needed to understand the evolution of things like bird wings and immune systems. I can discuss a lot about the evolution of the bird wing, and I can tell you, what you're doing is not science, it's butchery. <br /><br />The only reason I can see some people still clinging on to this "selection explains complex adaptation" thing is not for any great empirical documentation or true scientific support of such a thing. They do it to merely becuase this was the way Darwin understood natural selection as an alternative to paleys ( crappy) argument for design. <br /><br />The reasons, of course, for rejecting intelligent design reside in making the distinction of scientific or non-scientific explanations, and does not reside in any specific evolutionary mechanism. Maybe if neoatehists were smart enough to realize this they would stop trying to squish the entirety of evolutionary biology into the narrow box of "natural selection".A. Vargashttps://www.blogger.com/profile/04876504431768677209noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-52304793941267538772009-05-12T23:38:00.000-04:002009-05-12T23:38:00.000-04:00Viruses have lots of easy-to-understand examples o...Viruses have lots of easy-to-understand examples of "its not adaption, sometimes shit just happens." Sure, influenza makes you sneeze and polio makes you poop and chicken pox make you all blistery so these viruses can be transmitted person-to-person.<br /><br />But there is no evolutionary advantage to HPV causing cervical cancer. Sometimes, shit just happens.<br /><br />There is no evolutionary advantage to polio causing paralysis. Sometimes, shit just happens.<br /><br />There is no evolutionary advantage to HSV-1 causing blindness. Sometimes, shit just happens.<br /><br />Yay :PERVhttps://www.blogger.com/profile/02070086354372691880noreply@blogger.comtag:blogger.com,1999:blog-37148773.post-16899844749027846412009-05-12T20:03:00.000-04:002009-05-12T20:03:00.000-04:00Thanks for the post. Let me point out that I also...Thanks for the post. Let me point out that I also wrote this:<br /><br /><I>“Given Lewontin's past writing (most notably his spandrels paper with Stephen Jay Gould) I would guess that his point is that some biologists are too quick to attribute some anatomical feature of some organism to the prolonged working of natural selection.<br />”</I>This also seems to be the point you are making here.<br /><br />My concern is that in making this point some on your side of this use rhetoric that can easily be misconstrued. I think someone could read Lewontin's essay and come away thinking that natural selection is relatively insignificant in evolution. For exaple, Lewontin writes<br /><br /><I>“Where he [Jerry Coyne] is less successful, as all other commentators have been, is in his insistence that the evidence for natural selection as the driving force of evolution is of the same inferential strength as the evidence that evolution has occurred.”</I>I am sure I will be hearing that line at the next creationist conference I attend. I would feel better if Lewontin had added a line such as, “Certainly natural selection is a compelling explanation for complex structures like bird wings and immune systems, but there is much more to evolution than that.” <br /><br />At any rate, you would know better than I whether out of control adaptive thinking is a problem for biological research. My impression, though, was that Gould and Lewontin were really exaggerating the extent to which Just-So stories dominate the discourse.Jason Rosenhousehttp://www.scienceblogs.com/evolutionblognoreply@blogger.comtag:blogger.com,1999:blog-37148773.post-56864859259047213352009-05-12T18:36:00.000-04:002009-05-12T18:36:00.000-04:00On this topic, see Jerry Coyne's May 12 post on Ri...On this topic, see Jerry Coyne's May 12 post on Richard Lewontin’s review of Coyne's book Why Evolution Is True at <br />whyevolutionistrue.wordpress.comVeronica Abbasshttps://www.blogger.com/profile/07037599323472646996noreply@blogger.com