Science vs. Religion: (Chapter 4) (Humans)

by dhw, Wednesday, July 27, 2011, 13:27 (4663 days ago) @ xeno6696

Matt and Tony are having a right old ding-dong over whether Natural Selection does or doesn't explain anything. I think it does, but what it explains now seems so self-evident that some folk dismiss it as a tautology. Here is a child's eye view of the process:-"Once upon a time, people commented on how clever it was of God to make wigglies green, because their greenness made it difficult for birds to spot them among the green leaves, whereas if they had been red, the birds would have gobbled them up. Then along came Mr Darwin, who said that once upon an earlier time there had been red wigglies, but the birds had gobbled them up, and the only wigglies that survived were the green ones. And so in the course of time, the red ones disappeared altogether, leaving nothing but green ones. He called this Natural Selection."-(In passing, let us note that Natural Selection did not PRODUCE green wigglies; it merely ensured that green wigglies survived and red ones didn't.) -In the same exchange with Tony, Matt has mentioned Barry Hall's experiment as "a perfect example of a bacteria gaining a completely novel protein by entirely random mutation." Matt, you described the experiment in an earlier post as follows:-MATT: I've mentioned the Beta-Lactase experiment in which Barry Hall knocked out the gene that allowed a bacteria to digest lactose. A small population (that no longer had any recollection of lactose because of the knockout) modified a protein that allowed them to consume lactose again. This is an example of creation of a new function by random mutation and natural selection only.-I have a different interpretation of this experiment, so do by all means correct me. Firstly,according to your account it wasn't a "novel protein", but a modification of a protein to replace a missing gene. As I see it, this shows that a particular bacterium found a way to revert to type in order to aid its chances of survival. It is an example of adaptation, not innovation, and did not lead to a new species of bacterium. The mutation can hardly be called "random", since it involved a very specific adaptation to restore an ability that was clearly integral to its nature. How this shows the creativity of NS is beyond me. Does the experiment prove that NS can create new organs and new species? Of course not. If the pressure to survive actually created means of survival, no creature would ever die! The great question is how the bacterium managed to modify the protein, and that is the core of our disagreement. You "see no reason at all to assert that Natural Selection isn't enough", and yet even your own analysis of the case shows the vital role played by mutation. Without mutations (or changes of some kind) everything would remain exactly as it was, and there would be nothing for Nature to select from! -In your post to Tony, you quite rightly emphasize that "Evolution is clearly more complex than pure random mutations." Yes indeed. And it is clearly more complex than Natural Selection, which does not CREATE anything.