Early embryology; clockwork construction plan (Introduction)

by dhw, Tuesday, October 18, 2011, 14:36 (4785 days ago) @ David Turell

dhw: You have always said you believe that evolution happened, which can only mean that new species developed from existing species by means of heritable variations caused by innovations and/or adaptations.

DAVID: Of course evolution happened. But you are stuck with Darwin's explanation. Open your mind.

Hey, hold on! Unless you disagree with the above description of the evolutionary process (if so, please tell me why), there is nothing in your post that I have opposed. I much prefer Gould’s punctuated equilibrium to Darwin’s gradualism, am open to the epigenetic explanation of adaptation, and am in agreement with you that no-one knows how evolution proceeds – by which I mean the mechanisms that have created such a vast variety of species. The problem that concerns me most is that of innovation, and it was you who drew our attention to the Hox clock. The researchers said that “even the smallest change would end up leading to the emergence of a new species”, and they described it as demonstrating the “extraordinary complexity of evolution”. I asked for your explanation, and you said they meant monsters which were unlikely to survive. That sits uneasily with the words they used, and would block, not facilitate evolution, so I asked if they’d got it wrong, expressed themselves misleadingly, or really had got to the source of the mutations that result in new species. (Mutations should not be taken as synonymous with randomness.) It’s obvious that exact preservation is essential to the survival of existing species, but I’m asking about the emergence of NEW species, and your guess is that changes have been coded into the genome. Is there no possible link here with the Hox clock? My questions are genuine, I’d never heard of the Hox clock till now, and I’m not pushing any particular theory. You should know me better!