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Bezig met laden... Genetic Takeover: And the Mineral Origins of Lifedoor A. G. Cairns-Smith
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Meld je aan bij LibraryThing om erachter te komen of je dit boek goed zult vinden. Op dit moment geen Discussie gesprekken over dit boek. Cairns-Smith puts forward a rough outline on the origins of life. He believes that the "high-tech" machinery of RNA and DNA evolved from a simpler "low-tech" infrastructure that he argues was based on inorganic clay crystals. He begins by reviewing the traditional explanations given for the origins of life (Urey-Miller experiments and others) and explains why he believes these are improbable. He then dives deeply into the chemistry of inorganic clays and explains how their properties can account for replication, the passing on of information, and mutations. The basic properties of any evolvable system (however inefficient it may be). This is a fairly dense book that I would not recommend for the casual science reader. What it does offer are several creative ideas that fall outside of the traditional approach to life’s origins. It also provides a very interesting overview of the science of crystals, which I knew very little about. For a much gentler introduction to his ideas see his book "Seven Clues to the Origin of Life: A Scientific Detective Story". An even shorter summary of his ideas are presented in the June 1985 issue of Scientific American. geen besprekingen | voeg een bespreking toe
Three key ideas replace the notion that a primordial soup of organic molecules was essential in this explanation of how life on Earth evolved. Geen bibliotheekbeschrijvingen gevonden. |
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Google Books — Bezig met laden... GenresDewey Decimale Classificatie (DDC)577Natural sciences and mathematics Life Sciences, Biology EcologyLC-classificatieWaarderingGemiddelde:
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The title encapsulates his main message and that is that somewhere along the line nucleotides and amino acids evolved from something else: something simpler and something that was mineral based. He espouses the view that there was some form of mineral evolution that provided the templates for organic chemicals to develop and reproduce and once this happened the organic chemicals just took over and supplanted their earlier mineral based ancestry. (And, apparently, in the process, erased the signs of this ancestry. This step was what Cains-Smith describers as 'genetic takeover".
He favours the idea that clays are ideal candidates for the precursors of organic chemicals...or, at very least, they could be templates for replication and growth. There is an overwhelming amount of information and detail in the book ...so much so that it is hard to take it all in.
I did come away with the impression that Cairns-Smith has an unending series of examples of ways things MIGHT have developed ....some of them rather far-fetched but possible. But he's very weak on real examples of sequences of events that lend weight to his case.
I did think that he might have made more out of some of the evolutionary sequencing that seems to occur with Kaolinite changing into Allosite or similar natural sequence and I would have liked to have seen some situations with a bit more detail like that suggested in Fig 9.5 (p383).
But maybe Cairns-Smith was not the right person to take the proposal to the next level and, unfortunately, nobody else seems to have stepped up to the plate in the last 50 years.
I recently read the book "First Life" by David Deamer and it seems to be the current state of the art with "origins of life" theory. But rather disappointing and there is virtually no mention of Cairns-Smiths ideas. In fact, Deamer reveals his profound ignorance of clays and their absorptive capacity by taking an experiment to a volcanic pool in Siberia and basically dropping it in to see what would happen. Seems very naive to me:.......the clay immediately grabbed (adsorbed) all his organic chemicals ...and that was that.
Somewhere in Cairn's writings, he mentions that he took his ideas to the USA: The geologists thought his geology was fine but weren't quite sure about his biochemistry; The biochemists were happy with the biochemistry but thought the geology might be a bit suspect; The Chemists were happy with the Chemistry but thought the Geology needed some work...etc. I think that Deamer has little or no knowledge of clay Chemistry and probably most scientists around today are similar in that their knowledge doesn't roam over as broad a field as Cairns-Smith is attempting to embrace. A pity, because I think that Cairns-Smith might actually be onto something here. I won't try to summarise his data or arguments....there is too much there. But I did find it a fascinating book and happy to give it 5 stars. ( )