Intelligent Design, the best explanation of Origins

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Intelligent Design, the best explanation of Origins » Theory of evolution » The frailty of adaptive hypotheses for the origins of organismal complexity

The frailty of adaptive hypotheses for the origins of organismal complexity

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The frailty of adaptive hypotheses for the origins of organismal complexity 1

…It has long been known that natural selection is just one of several mechanisms of evolutionary change, but the myth that all of evolution can be explained by adaptation continues to be perpetuated by our continued homage to Darwin’s treatise (6) in the popular literature. For example, Dawkins’ (7–9) agenda to spread the word on the awesome power of natural selection has been quite successful, but it has come at the expense of reference to any other mechanisms, a view that is in some ways profoundly misleading…
What is in question is whether natural selection is a necessary or sufficient force to explain the emergence of the genomic and cellular features central to the building of complex organisms…
First, evolution is a population-genetic process governed by four fundamental forces. Darwin (6) articulated one of those forces, the process of natural selection, for which an elaborate theory in terms of genotype frequencies now exists (10, 11). The remaining three evolutionary forces are nonadaptive in the sense that they are not a function of the fitness properties of individuals: mutation is the ultimate source of variation on which natural selection acts, recombination assorts variation within and among chromosomes, and genetic drift ensures that gene frequencies will deviate a bit from generation to generation independent of other forces. Given the century of work devoted to the study of evolution, it is reasonable to conclude that these four broad classes encompass all of the fundamental forces of evolution.
Second, all four major forces play a substantial role in genomic evolution. It is impossible to understand evolution purely in terms of natural selection, and many aspects of genomic, cellular, and developmental evolution can only be understood by invoking a negligible level of adaptive involvement (12, 13).
Natural selection is just one of four primary evolutionary forces. [Quote from Table 1]
There is no evidence at any level of biological organization that natural selection is a directional force encouraging complexity. In contrast, substantial evidence exists that a reduction in the efficiency of selection drives the evolution of genomic complexity.[Quote from Table 1]
The literature is permeated with dogmatic statements that natural selection is the only guiding force of evolution, with mutation creating variation but never controlling the ultimate direction of evolutionary change (for a review, see ref. 17)…
Most biologists are so convinced that all aspects of biodiversity arise from adaptive processes that virtually no attention is given to the null hypothesis of neutral evolution, despite the availability of methods to do so (32–34)…
The hypothesis that expansions in the complexity of genomic architecture are largely driven by nonadaptive evolutionary forces is capable of explaining a wide range of previously disconnected observations (13, 40) (Table 2). This theory may be viewed as overly simplistic. However, simplymaking the counterclaim that natural selection is all powerful (without any direct evidence) is not much different from invoking an intelligent designer (without any direct evidence)…
Certainly, many of the above-mentioned embellishments of eukaryotic genes have adaptive functions in today’s multicellular species, but observations on current deployment may have little bearing on matters of initial origins…
Multicellularity is widely viewed as a unique attribute of eukaryotes, somehow made possible by the origin of a more complex cellular architecture and, without question, with the assistance of natural selection. However, it is difficult to defend this assertion in any formal way…
Nevertheless, King (45) states that “this historical predisposition of eukaryotes to the unicellular lifestyle begs the question of what selective advantages might have been conferred by the transition to multicellularity;” and Jacob (46) argues that “it is natural selection that gives direction to changes, orients chance, and slowly, progressively produces more complex structures, new organs, and new species.” The vast majority of biologists almost certainly agree with such statements. But where is the direct supportive evidence for the assumption that complexity is rooted in adaptive processes? No existing observations support such a claim, and given the massive global dominance of unicellular species over multicellular eukaryotes, both in terms of species richness and numbers of individuals, if there is an advantage of organismal complexity, one can only marvel at the inability of natural selection to promote it. Multicellular species experience reduced population sizes, reduced recombination rates, and increased deleterious mutation rates, all of which diminish the efficiency of selection (13). It may be no coincidence that such species also have substantially higher extinction rates than do unicellular taxa (47, 48)…
…[C]ontrary to popular belief, natural selection may not only be an insufficient mechanism for the origin of genetic modularity, but population-genetic environments that maximize the efficiency ofnatural selection may actually promote the opposite situation, alleles under unified transcriptional control…
Although those who promote the concept of the adaptive evolution of the above features are by no means intelligent-design advocates, the burden of evidence for invoking an all-powerful guiding hand of natural selection should be no less stringent than one would demand of a creationist…
If complexity, modularity, evolvability, and/or robustness are entirely products of adaptive processes, then where is the evidence? What are the expected patterns of evolution of such properties in the absence of selection, and what types of observations would be acceptable as a falsification of a null, nonadaptive hypothesis?

1) http://www.pnas.org/content/104/suppl_1/8597.full
http://www.uncommondescent.com/intelligent-design/larry-moran-defends-paul-nelson/

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