Back to irreducible complexity (PART TWO) (Introduction)

by dhw, Friday, January 29, 2010, 17:31 (5208 days ago) @ dhw

PART TWO-Shapiro's article on "Mobile DNA and evolution in the 21st century" is a model of scientific neutrality, and some of the discoveries are breathtaking, though for a layman like me a lot of it is far too technical. I found a less daunting, and far shorter article called "A Third Way" on: www.bostonreview.net/BR22.1/shapiro.html -I'll quote from both articles, though. It seems to my untrained eye that he disposes once and for all of the gradualism so essential to Darwinism: "We have progressed from the Constant Genome, subject only to random, localized changes at a more or less constant mutation rate, to the Fluid Genome, subject to episodic, massive and non-random reorganizations capable of producing new functional architectures." -He thinks the new view of genome restructuring "helps us to formulate reasonable hypotheses about two unresolved questions in evolutionary theory: (i) the connections between evolutionary change and ecological disruption; and (ii) the origin of complex adaptive novelties at moments of macroevolutionary change." This is a huge claim, but he goes into details, with emphasis on the cell as a "multilevel information-processing entity". Matt will be pleased to read this: "Upsetting the oversimplified views of cellular organization and function held at mid-century, the molecular revolution has revealed an unanticipated realm of complexity and interaction more consistent with computer technology than with the mechanical viewpoint which dominated the field when the neo-Darwinian Modern Synthesis was formulated."-Linking up with the Buchanan article above, he says: "From countless experiments, we now have overwhelming evidence for horizontal DNA transfer between species and between the three kingdoms of living cells." He also refers to WGD (whole genome doubling) as "another evolutionary process outside the Darwinist perspective that occurs suddenly (that is, within a single generation) and simultaneously affects multiple phenotypic characters." The objection to gradualism that it is "too slow and indeterminate a process to account for natural adaptations" can be met by molecular mechanisms that "utilize the demonstrated capabilities of mobile DNA and other natural engineering mechanisms." One of these is the response to a "genome shock" (e.g. a geological upheaval) as a result of which "novel changes at multiple locations in the genome can arise within a single generation and can produce a progeny expressing all the changes at once. There is no requirement, as in conventional theory, that each individual change be beneficial by itself." But Shapiro does not pretend to have all the answers: "How a newly symbiotic cell or one with a newly doubled genome manages the transition to a stable genome structure that replicates and transfers reliably at cell division is another important subject for future research." And "there remain many gaps in our knowledge."-Let me finish with some quotes that are relevant to our own discussions: -"The potential for new science is hard to find in the Creationist-Darwinist debate. Both sides appear to have a common interest in presenting a static view of the scientific enterprise." (He includes Dawkins.) -The 21st century view of evolution "answers the objections to conventional theory raised by intelligent design advocates, because evolution by natural genetic engineering has the capacity to generate complex novelties." -"Dogmas and taboos may be suitable for religion, but they have no place in science."-Once again, my thanks to David for bringing all of this to our attention. I am now a Shapiro fan!