Tuesday, March 17, 2015

Evolution's direction

From "The direction of evolution: the rise of cooperative organization." In Biosystems, Volume 123, September 2014, Pages 27–36

An excerpt:

"The hypothesis that seems to have gained most support is that selection tends to drive increasing complexity as evolution proceeds. [...] It is obvious that complexity per se is not favoured by selection. There are numerous possible changes in organisms that would increase complexity but are not advantageous in evolutionary terms. And changes that are less complex are not always inferior.

"Proponents of this claim have been unable to identify how known evolutionary processes would drive the supposed trend towards increasing complexity. This is a serious deficiency that also bedevils other attempts to demonstrate an overall, driven trend in evolution. To demonstrate such a trend, it is not sufficient to identify some supposed large-scale pattern in evolution and to marshal empirical evidence that substantiates the existence of the pattern. The pattern may be an artefact and not driven by selection that directly favours the pattern. It is therefore also necessary to provide the claimed directionality with micro-foundations at the level of natural selection that show how the pattern is driven by selection and related processes.

"This has proven particularly challenging because it is not at all obvious how natural selection could drive a trajectory encompassing all living processes, given that it produces only local adaptation to local circumstances (Gould, 1996 and Maynard Smith, 1988).

"This deficiency obviously cannot be overcome by the postulation of some new general ‘force’, ‘tendency’ or ‘drive’ that is unsupported by appropriate micro-foundations. Nor can it be overcome by teleological explanations that rely on impermissible ‘pulls from the future’."

And from the conclusion:

"Evolution has been heading towards the emergence of a coordinated and integrated global entity."

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