Friday, February 27, 2015

The Ilusion of Organisms' Sexual Preferences

Despite of the gene view as the unit of selection, explanations for sexual preferences and evolution of secondary sexual traits are invariable done at the level of the Organisms' Sexual Preference, more specific, the female preference. The best example comes from the Fisher Runaway model, where a exacerbated choice of females for an ostensive trait it will promote the evolution of that trait, even when it causes prejudice in terms of ability to escape from predators, a physical disadvantage promoted by Sexual Selection.


The explanation for this handicap is that it guarantees that males with bad genes aren't able to cope with the ornament and so, to survive, the ornament is neglected signing him as a bad mate.  Here there is immediately a contradiction, calling this a non-adaptive trait despite representing a selective advantage! Clearly there is a confusion of not know for sure if it is Sexual or Natural Selection who promotes those traits. However, these confusion is more or less solved in the case of Sex Ratios, where approaches like Evolutionarily Stable Strategy (ESS) give a more Natural Selection perspective, making evident that Sexuality here makes part of the Environment that supports Natural Selection. This is even more evident when Hamilton argues that the Stable Sexual Ratio isn't necessary 1:1 as supported by Fisher. These Extraordinary Sex Ratios show that is Natural Selection and not Sexual Selection that shapes Sexual Reproduction, because the external Environment action is the main cause. With these new models more supported in math than female preferences, it's clearly the Survival of the Fittest that counts in this general Environment with or without Sexual reproduction as part of it.

Despite all this signs that point out to Species Selection, that show Natural Selection as the only force in Evolution, things like Red Queen Hypothesis continue to be supported and Sexual Selection is still seen as one source of Evolution like Natural Selection is. All this theories are captured in a very basic materialistic view, the Red Queen Hypothesizes where sex evolved because new and unfamiliar combinations of genes could be presented to parasites, preventing the parasite from preying on that organism, is a very lame justification. How can some one believe that thousand of million of yeas, that made Sexual Selection ubiquitous in all Eukaryote Species turns out to exist just to save those species from parasites? How can some one conclude that because crossing over allows endless different gene combinations it means that the purpose of Sexual Selection is diversity?

Is there a way to scape from this childish and basic way of thinking? Is there a way of center evolution where it really happens? Is there a way to understand Sexual Selection as something that restricts and controls Evolution? Is there a way to prove that Evolution is only caused by Natural Selection?

Sometimes some one is able to see further, sometimes some one points out cracks in the gene centered microevolution. In a issue entitled The counterintuitive role of sexual selection in species maintenance and speciation, is concluded that:
Using population genetic modeling techniques, we find that if allopatric populations come into contact via the onset of gene flow, sexual selection, in its purest form, takes on an inhibitory role, drastically reducing trait differentiation due to divergent local adaptation. This is due to the fact that under this Fisherian model, preferences, which are not under direct selection, equilibrate with little population differentiation, even though trait frequencies may differ greatly due to local adaptation. This creates relatively greater mating opportunities for foreign, rare males in each population, directly countering the effects of local adaptation and reducing population differentiation at a trait locus. Importantly, stronger preferences exaggerate this effect. Fisherian sexual selection is thus a double-edged sword in the development of isolation under these conditions, potentially driving differentiation in allopatry but removing it if there is contact. Ultimately its role in allopatric speciation is tenuous, failing even if contact is initiated after substantive trait and preference divergence has occurred.
Yes, macroevolution is counterintuitive, yes Species Selection is counterintuitive, yes depart from Materialism is counterintuitive, but nevertheless is the path to truth! However the idea is quite simple, crossing over in Sexual Selection is itself a departure from materialistic restrictions. Instead of Natural Selection being made on Organisms, like in prokaryotes where the genome isn't fragmented by any crossing over, with Sexual Reproduction it's made on Species, but because Species are something abstract, something Logic and not Physical, intuitively Natural Selection is seen as acting on genes, just because genes are at the Physical level! Genes are no more than the needed infrastructure to Species, they are encapsulated and maintained accordingly to the species survival to which they belong. The same way selection at the level of Organisms is limited to explain evolution in Eukaryotes, Genes are the panacea that nowadays is used to explain a more complex reality than the one materialism is able to.

The first one to contradict the gene as the Unit of Selection was Stephen Jay Gould, supporting Species Selection, become attacked by the mainstream:
John Maynard Smith, one of the world's leading evolutionary biologists, recently summarized in the NYRB the sharply conflicting assessments of Stephen Jay Gould: "Because of the excellence of his essays, he has come to be seen by non-biologists as the pre-eminent evolutionary theorist. In contrast, the evolutionary biologists with whom I have discussed his work tend to see him as a man whose ideas are so confused as to be hardly worth bothering with, but as one who should not be publicly criticized because he is at least on our side against the creationists." (NYRB, November 30, 1995, p. 46). No one can take any pleasure in the evident pain Gould is experiencing now that his actual standing within the community of professional evolutionary biologists is finally becoming more widely known. If what was a stake was solely one man's self-regard, common decency would preclude comment. But as Maynard Smith points out, more is at stake. Gould "is giving non-biologists a largely false picture of the state of evolutionary theory"—or as Ernst Mayr says of Gould and his small group of allies—they "quite conspicuously misrepresent the views of [biology's] leading spokesmen."{1}. Indeed, although Gould characterizes his critics as "anonymous" and "a tiny coterie", nearly every major evolutionary biologist of our era has weighed in a vain attempt to correct the tangle of confusions that the higher profile Gould has inundated the intellectual world with.{2} The point is not that Gould is the object of some criticism—so properly are we all—it is that his reputation as a credible and balanced authority about evolutionary biology is non-existent among those who are in a professional position to know. - http://cogweb.ucla.edu/Debate/CEP_Gould.html

However, against all this genetic fundamentalism as unit of selection, it looks like there are a lot to explore, and Species Selection turns out not to be a nonsense like the mainstream tries to make it.
Species selection in the broad sense—also termed species sorting—shapes evolutionary patterns through differences in speciation and extinction rates (and their net outcome, often termed the emergent fitness of clades) that arise by interaction of intrinsic biological traits with the environment. Effect-macroevolution occurs when those biotic traits, such as body size or fecundity, reside at the organismic level. Strict-sense species selection occurs when those traits are emergent at the species level, such as geographic range or population size. The fields of paleontology, comparative phylogenetic analysis, macroecology, and conservation biology are rich in examples of species sorting, but relatively few instances have been well documented, so the extent and efficacy of the specific processes remain poorly known. A general formalization of these processes remains challenging, but approaches drawing on hierarchical covariance models appear promising. Analyses integrating paleontological and neontological data for a single set of clades would be especially powerful. - Species Selection: Theory and Data
Terms like Organism and Species Level are clear clues to a multi layered scheme in opposition to a flat one. So, step by step, some are peeking bellow the surface, and selection by layers isn't a taboo anymore:
Does natural selection act primarily on individual organisms, on groups, on genes, or on whole species? This book provides a comprehensive analysis of the long-standing controversy in evolutionary biology over the levels of selection, focusing on conceptual, philosophical, and foundational questions. In the first half of the book, a systematic framework is developed for thinking about natural selection acting at multiple levels of the biological hierarchy; the framework is then used to help resolve outstanding issues. Considerable attention is paid to the concept of causality as it relates to the levels of selection, particularly the idea that natural selection at one hierarchical level can have effects that ‘filter’ up or down to other levels. Full account is taken of the recent biological literature on ‘major evolutionary transitions’ and the recent resurgence of interest in multi-level selection theory among biologists. Other biological topics discussed include Price's equation, kin and group selection, the gene's eye view, evolutionary game theory, selfish genetic elements, species and clade selection, and the evolution of individuality. Philosophical topics discussed include reductionism and holism, causation and correlation, the nature of hierarchical organization, and realism and pluralism about the levels of selection. - Evolution and the Levels of Selection - Samir Okasha
Step by step Species will be king in terms of Natural and Sexual Selection, while genes have been just a momentary fascination for the detail, like atoms in TVs, Cars and Refrigerants with mainstream biologists as physicists explaining the evolution of Coca Cola at the Atomic level, ignoring that Coca Cola, like Species, is selected as a whole, by the Environment of consumers.

Like Evolution centered at the Organism Level lost its veracity for Eukaryotes, so it will be at the Genes Level, because an house is not a brick, just happens to be made of it.
Most analyses of species selection require emergent, as opposed to aggregate, characters at the species level. This "emergent character" approach tends to focus on the search for adaptations at the species level. Such an approach seems to banish the most potent evolutionary property of populations--variability itself--from arguments about species selection (for variation is an aggregate character). We wish, instead, to extend the legitimate domain of species selection to aggregate characters. This extension of selection theory to the species level will concentrate, instead, on the relation between fitness and the species character, whether aggregate or emergent. Examination of the role of genetic variability in the long-term evolution of clades illustrates the cogency of broadening the definition of species selection to include aggregate characters. We reinterpret, in this light, a classic case presented in support of species selection. As originally presented, the species selection explanation of volutid neogastropod evolution was vulnerable to a counterinterpretation at the organism level. Once this case is recast within a definition of species selection that reflects the essential structure and broad applicability of hierarchical selection models, the organism-level reinterpretation of variability loses its force. We conclude that species selection on variability is a major force of macroevolution. - Species selection on variability
All turns out to be Species' Sexual Preferences!

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