Contingent evolution: what pushes it? (Introduction)

by David Turell , Monday, November 03, 2014, 14:39 (3463 days ago) @ Balance_Maintained

David To me contingent evolution means one step follows another. For Gould this meant a chance sequence. Evolution is either by chance or it is planned. There is no third way.
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> Tony: Unless you are lumping this under "planned", there is a third way. That third way is variation within kinds confined by stringent limitations. It is kind of the halfway point between the two you listed. It allows for change (read evolution) and adaptation (read evolution) but only within tightly defined parameters, some of which will automagically default back to their original settings after several generations if the originating pressure that triggered the change is removed (read epigenietics).-This is my position exactly, but you have stated it better than I have in my DILEMMA discussions. You are describing what I think of as micro-evolution, adaptive changes in fully established species. And this is all an inventive mechanism can do. We cannot excape the fact that the fossil rcord repeatedly tells us all new advanced species arrive full-blown, fully functional. This is the loud and clear message from the Cambrian Explosion.-I don't view your point as a third way, but a method by which species can adapt to challenges for the time being or permanently. But, they are still the same species. Just as penicillin-resistent Staph aureus are still Staph. It is what Shapiro's research is all about.