Evolution: a different view (Introduction)

by David Turell , Sunday, May 03, 2015, 00:53 (3492 days ago) @ David Turell
edited by David Turell, Sunday, May 03, 2015, 01:04

Another reference to exaptation by Tattersall which makes my point. On page 8 of the article:-"Whatever it may have been that ushered in the beginnings of symbolic thought in a species H. sapiens that, like all other organisms, had lived until that point in a concrete external world rather than in one constantly mentally remade, it is clear that symbolic thought itself cannot have been propelled into existence by natural selection. Indeed, natural selection is not a creative force; it can only exert itself on variations that come into existence spontaneously. In this sense, any useful novelty has to arise not as an adaptation but as an exaptation (Gould and Vrba, 1982 ): as a feature that is not acquired in the context of any function to which it might eventually be put. The vocal structures that make language possible are a prime example of this. - The bottom line here is that nothing arises for anything, and selection can only work with what is already there. Sometimes, novelties persist in populations for no better reason than that they do not get in the way. Looking at the matter from this perspective takes the origin of our vaunted human cognitive capacities out of the arena of gradual honing by natural selection, placing it instead in that of emergence (Tattersall, 2004, 2008 ). That is to say, an entirely new and unanticipated level of cognitive complexity was acquired as
result of an entirely fortuitous coincidence of acquisitions. The whole, in other words, is greater than the sum of its parts." (Again, my bold)-http://www.imd.inder.cu/adjuntos/article/455/Human%20Brain%20Evolution.pdf#page=23-I've read many Tattersall articles, which influenced my approach to this concept of exaptations as being very important.-For further reading an article on the two types of exaptation, which again quotes Tattersall:-http://www.wcaanet.org/downloads/dejalu/may_2013/pievani.pdf -"Ian Tattersall used exaptation as a powerful explanatory hypothesis for a clearly defined subject, though crucial, such as the emergence of symbolic intelligence in Homo sapiens during the Palaeolithic Revolution. However, in the citation above he expressed a more radical perspective seeing exaptation (in prevalence type 2) as a general evolutionary pattern. It is noteworthy that Stephen J. Gould himself assumed a similar position at various points in his work. Interestingly, the statement below occurs in the very work where he examined most of the points we make
here about the operationality of exaptation: “I cannot present a ‘review article' of empirical cases of exaptation, for the defining notion of quirky functional shift might almost be equated with evolutionary change itself, or at least with the broad and venerable subject of, in textbook parlance, ‘the origin of evolutionary novelties'” (Gould, 2002, p. 1234)."