Complexity of gene codes (Introduction)

by dhw, Monday, August 23, 2010, 19:02 (5015 days ago) @ David Turell

David believes that the mechanisms leading from the simplest forms of life to the most complex were all in place from the very beginning. I'll select some salient quotes from the Complexity thread and the Ain't nature wonderful thread:-"[..] recent work is showing that the earliest organisms appear to have a very complex adaptation mechanism in the genome."-"The first organisms at 3.6 bya had to face enormous environmental changes. [...] Without those initial adaptive abilities it is unlikely life would have survived."-"If Archaia have these adaptive processes from the beginning, then these rapid adaptation mechanisms drive evolution forward to the more and more complex forms. [...] presuming Archaia haven't changed much, epigenetics was there from the beginning."-I find all of this convincing, but the sting is in the tail, which leads me to a whole string of questions. Archaia adapted in order to remain Archaia. Adaptation does not explain innovation. There is therefore an additional problem of origin, quite apart from that of life itself: how do we explain the origin of new organs and indeed of new species? (Natural selection doesn't innovate.) There has to be a mechanism for random, occasionally beneficial, inheritable mutations (which of course might also be triggered by the environment), and if that was in place from the start, would there not also have been such mutations from the start? -The same applies to complexity. The earliest known complex forms are now believed to date back 2.1 billion years (Gabon fossils). So what do you reckon went on during the first 1.5 billion years, if mechanisms for innovation and increasing complexity were already in place? Of course we may never know, but if you're right, might we not expect to find even older complex forms? And if the Cambrian explosion was caused by dramatic changes in the environment but the mechanisms for adaptation and innovation were already present right from the start, wouldn't the "enormous environmental changes" 3.6 bya and onwards have caused similar explosions? -It seems to me that innovation adds to the complexity of the mechanisms (which reinforces the argument against chance), but the apparent stasis for 1.5 billion years and the presumption that Archaia haven't changed much do nothing to reinforce the argument that all the mechanisms for evolution were in place from the beginning. However, I still can't see why it makes any difference to the design (or chance) theory whether they were or weren't in place then.