Natures wonders: bacteria can spear amoebas (Introduction)

by dhw, Friday, September 01, 2017, 13:17 (2427 days ago) @ David Turell

DAVID: Raup stated extinctions were almost always due to bad luck, not adapting quickly enough.
dhw: So it was bad luck that some organisms were not able to adapt quickly enough (= unable to cope with conditions at the time) and were therefore not fit to survive. And those that did adapt quickly enough (i.e. did cope with conditions at the time) were fit to survive. So how does that make fitness to survive an “unproven conjecture”?
DAVID: Because it was Raup's concept that the existing species were surviving just fine until the unusual extinction catastrophe occurred. They were fully adapted to the existing conditions. Over the 3.6 billion years of life there have been just six major extinctions, so he felt they did not play a role in day to day evolution. Obviously they had a major effect.

Every species that has gone extinct was fine until it went extinct! So may I tentatively suggest to you (or Raup) that major catastrophes or environmental changes (e.g. an increase in oxygen levels) would have had “a major effect” on which organisms perished and which organisms survived and gave rise to new organisms that could also cope with or exploit the new conditions, while minor catastrophes or environmental changes would have had ”a minor effect” (though minor effects may have led to major effects, since evolution is an ongoing process). And may I even suggest that survivability is therefore not an “unproven conjecture”, but so obviously plays a major role in the success or failure of all adaptations and innovations that it is hardly worth arguing about.

DAVID: The beaks are within a species variation according to recent genetic research and simple epigenetics […]

dhw: You have agreed that major adaptations are innovations, and now you are repeating my examples of minor and major adaptations. The fact that we don’t understand the major alterations is the reason why we look for explanations and offer unproven hypotheses. I have suggested that since both minor adaptations and major adaptations are adaptations, the same mechanism might be responsible for both. You accept autonomy for the one but not for the other. Epigenetics are not “simple”. What do you think is the autonomous mechanism that enables finches to change the form of their beaks in order to cope with their respective environments?

DAVID: Epigenetic changes are editing of the DNA by methylation, etc., and fit Shapiro's gene editing in bacteria. The finches are not that changed, just beak size and shape alterations. It is the magnitude of adaptation that makes me differ with you. Leg to flipper, nostrils to blow hole are major changes that require visualization of the outcome of the change to set up the proper planning for the change. When we find that mechanism ability present in living organisms, I will only then agree with your theory. The fact that speciation is still so mysterious, with no hints in current research, supports me.

You keep repeating the point that I keep answering. Yes, finch beaks are minor and flippers and blow holes are major, but you have agreed that they are all adaptations, and so the same mechanism may be at work. Now do please tell me whether you think your God dabbled with finch beaks (or preprogrammed them 3.8 billion years ago), or their cell communities autonomously used their (possibly God-given) intelligence to work how to “edit their DNA by methylation etc.” In the meantime, I do not ask you to agree with my hypothesis – I also have reservations. I only ask you to consider it as a possibility. The mystery does not in any way support your theory that there is a supernatural power which designed flippers before pre-whales entered the water.