Complexity of gene codes (Introduction)

by David Turell , Wednesday, August 25, 2010, 06:08 (5014 days ago) @ dhw


> It seems to me that our knowledge of life over this vast stretch of time is so scant that no matter what new discoveries are made concerning genome complexity, it is impossible to say with any degree of certainty whether all the mechanisms needed for evolution were already present in the earliest forms of life. (I also wonder how one can talk of an explosion when we know so little about the forms of life that existed beforehand!)-No we cannot be certain that Archaia are unchanged. So far the scarcity of pre-existing forms may be real, but the jump from Edicaran sheets of cells is all we have, so 'explosion'.
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> but adaptability is still a far cry from innovation, which is the problem I find most puzzling.-You are mising my point. I'll repeat: Epigenetic changes in the genome can be heritable, and thus adaptations can become innovations.
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> Interestingly, however, you say in relation to the Cambrian Explosion that the increased oxygen "allowed the genome to perform and create new organs and organisms", and it would be immensely helpful if you could elaborate on this, even if you think there must have been other factors too.-This is the current Darwinian explanation. I know of no other factors. These forms appear 'out of thin air'.
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> I'm not questioning that evolution happened, and of course natural selection played its part in preserving advantageous changes, but I'm trying to fill the gap between adaptation and innovation. -I feel they are one and the same. Inheritable adaptations can gradually or quickly become innovations. Darwin guessed at 'slow' change. He was watching the work of breeders. We now recognize that evolution can move rather quickly. It appears we are finding both stasis followed by puctuated equilibrium advances, and just punctuated advances with no stasis preceding.