Precedence of Phenotype or Genotype in the evolution of 'novel' traits.

In the Re-Theory of Evolution thread, Bluejay and Bertvan have been discussing whether genetic changes precede or follow phenotypic changes.Bertvan stated that ... The last part of this sounds quite like a real phenomenon, that of genetic assimilation. Genetic assimilation involves environmental effects giving rise to particular phenotypes which can then become genetically 'fixed' as it were so the environmental stimulus is no longer required.The problem is that there is no evidence this is in any way connected to any 'creative response'. Phenotypic responses to the environment are still mediated by the interaction of the organisms genome with its environment. There is nowhere else for the 'responses' Bertvan posits to come from.There is certainly no evidence that such 'responses' are purposeful or guided by any form of intelligence.Bluejay countered ... There is certainly plenty of empirical evidence from hundreds of mutational studies to support this, although it does not perhaps give the neccessary credence to the idea that instances where phenotypic change has preceded genotypic change (in some sense at least) may still have considerable significance.These arguments raise these questions to my mind ...Is there a coherent argument to be made for any sort of entirely genetically independent epigenetic inheritance becoming genetically encoded over generations?Is there any reason to suppose that such a mechanism would in any way require intelligence to operate?Is too much emphasis put on purely genetic changes and not on the long term interactions between the genotype and the environment?TTFN,WK

It's a bit of a toss up. Definitely the basic framing of the question is in terms of 'simple' biological evolution, but Bertvan's ideas, which I would like to discuss, are definitely firmly ID.I'd go with your instinct and put it into 'Biological Evolution'. The ID aspect is not the primary one and Bertvan already has his own PNT on some of his ideas on 'intelligence' and the immaterial.TTFN,WK

But what is the basis of this differential response? I think that RAZD's point is that we would expect genetically identical organisms to respond in the same way to identical environments and that the spectrum of mutation we would expect to see would still be random, not directed towards particular beneficial responses to environmental challenges.Surely the basis of the different responses to environmental 'cues' is going to be in genetic variation in the population, and that variation means that the organisms are not identical.I think RAZD's hypothetical refers to something like an experiment where antibiotics are added to a culture and in the next generation there are several independent mutations all beneficial to the bacteria in terms of survival in an antibiotic environment, i.e. all the bacteria got their little bacterial thinking caps on and came up with different novel strategies for coping. The most important distinction between such a scenario and what actually happens, apart from the caps, is that in generations after the antibiotic is added, provided it is not immediately lethal there will be a wide spectrum of both beneficial and detrimental mutations, one might argue of course that a 'creative response' could also include detrimental mutations.The situation needs framed differently of course when you add a stricter bacteriocidal immediately lethal antibiotic regime to a grown culture, in that case you are principally looking for pre-existing genetic variation providing differential survivability, in which case you would have to think of the 'creative response' as pre-emptive.TTFN,WK