dubois@uwmacc.UUCP (Paul DuBois) (04/16/85)
>>> You want maybe some sort of useless >>> half-feather? Why would something like that be selected for? Why would >>> you expect a specie with useless features to survive long enough to leave >>> any kind of fossil record? >> >> Like the Irish Elk? > What useless features do you think the Irish Elk had, Paul? Why do you think > they were useless? The antlers. I think they were useless because of all the effort Gould goes to, to show they weren't (i.e., that they were adapted)! -- | Paul DuBois {allegra,ihnp4,seismo}!uwvax!uwmacc!dubois --+-- | Science is Dead. |
mrh@cybvax0.UUCP (Mike Huybensz) (04/17/85)
In article <902@uwmacc.UUCP> dubois@uwmacc.UUCP (Paul DuBois) writes: > > What useless features do you think the Irish Elk had, Paul? Why do you > > think they were useless? > > The antlers. I think they were useless because of all the effort Gould > goes to, to show they weren't (i.e., that they were adapted)! Do you mean to say that it is Gould's behavior, rather than scientific criteria, that is deciding your belief? Antler size in Cervids (deer, etc.) is very important in recruiting and defending a harem, which of course is crucial to reproductive success. Larger antlers might enable an individual to garner a larger harem. Thus they would be useful to the individual. This is called sexual selection. Secondary sex characters (such as size of males in most carnivores, coloration in many male birds, and a host of others tend to become very exaggerated. There are probably limiting tradeoffs for the size of antlers. We just don't know what conditions were for the Irish Elk that minimized the penalties involved in having large antlers. The elk probably became extinct when humans arrived on the scene and changed conditions by hunting, burning, wood cutting, or whatever. -- Mike Huybensz ...decvax!genrad!mit-eddie!cybvax0!mrh
dubois@uwmacc.UUCP (Paul DuBois) (04/23/85)
> [Mike Huybensz] > In article <902@uwmacc.UUCP> dubois@uwmacc.UUCP (Paul DuBois) writes: >>> What useless features do you think the Irish Elk had, Paul? Why do you >>> think they were useless? >> >> The antlers. I think they were useless because of all the effort Gould >> goes to, to show they weren't (i.e., that they were adapted)! > Do you mean to say that it is Gould's behavior, rather than scientific > criteria, that is deciding your belief? Well, not *quite*...let's say that Gould's efforts to explain the antlers adaptively aroused my suspicions as to the presence of a problem. I don't really know if they are useless or not. I gave the example as I thought perhaps it would stimulate someone to respond further. Since you have taken the trouble to do so (thank you), I will reply. Gould addresses this topic in one of his Natural History essays (also in _Ever Since Darwin_) and in _Evolution_ [1,2]. He takes a look at the antlers and, unwilling to believe that natural selection would result in something non-adaptive he decides that they have some sort of function, about which he speculates, unconvincingly and without proof. I'm not saying that they might not indeed really have been adaptive. But his argument is facile. Don't take my word for it. Read it yourself. You might say that my ears pricked up when I detected his faith that there is an adaptive explanation. This is not all. I said that his argument was not convincing, but there is more. I add that in this matter we find Dr. Gould in one of his inconsistencies. He takes pains to discover an adaptive function (one dare not say purpose) for these antlers, yet elsewhere we notice that he derides the "adaptationist program" thus: "The emphasis on natural selection as the only driving force of any importance in evolution led inevitably to an analysis of all attributes of organisms as adaptations. Indeed, the tendency has infected our language, for, without thinking about what it implies, we use 'adaptation' as our favord, _descriptive_ term for designating any recognizable bit of changed morphology in evolution. I believe that this 'adaptationist program' has had decidedly unfortunate effects in biology. It has led to a reliance on speculative storytelling in preference to the analysis of form and its constraints; and, if wrong, in any case, it is virtually impossible to dislodge because the failure of one story leads to invention of another rather than abandonment of the enterprise" [3p128]. This statement applies to his own useless speculations regarding the Irish Elk. This is somewhat reminiscent of his toils in compiling data for thousands of species for his spindle diagrams to marshall support for the notion that the Cambrian explosion is simply the log phase of a sigmoid curve [4], only to later refer to this event as "the greatest of all geological bangs" [5]. He sits on both sides of several fences. > Antler size in Cervids (deer, etc.) is very important in recruiting and > defending a harem, which of course is crucial to reproductive success. > Larger antlers might enable an individual to garner a larger harem. And they might not. How do antlers function to recruit females? Davidheiser points out that "often an antlerless stag is a master stag, and a successful leader of stags, and furthermore...an antlerless stag usually has the largest harem of females" [6p197]. > Thus they would be useful to the individual. This is called sexual selection. > Secondary sex characters (such as size of males in most carnivores, coloration > in many male birds, and a host of others tend to become very exaggerated. So? > There are probably limiting tradeoffs for the size of antlers. We just don't > know what conditions were for the Irish Elk that minimized the penalties > involved in having large antlers. The elk probably became extinct when > humans arrived on the scene and changed conditions by hunting, burning, > wood cutting, or whatever. We don't even know that the penalties *were* minimized. We certainly don't know why they went extinct. You are speculating and that is all. --- References [1] Stephen Jay Gould, _Ever Since Darwin_, chapter 9. W W Norton, New York, 1977. [2] Stephen Jay Gould, "The Origin and Function of 'Bizarre' Structures: Antler Size and Skull Size in the 'Irish Elk,' _Megaloceros Giganteus_". Evolution, 28(2), June 1974, 191-220. [3] Stephen Jay Gould, "Is a new and general theory of evolution emerging?" Paleobiology, 6(1), 1980, 119-130. [4] Stephen Jay Gould, "The Interpretation of Diagrams". Natural History, 85(7), August-September 1976, 18-28. This is reprinted as "Is the Cambrian Explosion a Sigmoid Fraud?" in _Ever Since Darwin_, W W Norton, New York, 1977, 126-133. [5] Stephen Jay Gould, "The Ediacaran Experiment". Natural History, 93(2), February 1984, 14-23. [6] Bolton Davidheiser, _Evolution and Christian Faith_". Presbyterian and Reformed Publishing, Phillipsburg, N J, 1969. -- | Paul DuBois {allegra,ihnp4,seismo}!uwvax!uwmacc!dubois --+-- | "Danger signs, a creeping independence" |