Natural Selection (Evolution)

by dhw, Sunday, August 07, 2011, 16:29 (4667 days ago) @ dhw

PART TWO-As for Beta-LactamaseHW: In other words, how does random change constitute a response?-MATT: In the case of Hall's experiment, it wasn't a response. The change that resulted in gaining a function of beta lactamase came about by frame-shifts over generations. The key point from Miller is precisely that raw natural selection could result in something novel--something both yourself and David have previously rejected. The fact that it happened at LEAST once... means that the statement that nothing new can be created by classic Darwinian selection is false.-I can't follow your logic. You said the experiment was an example of random mutation and natural selection (the latter, according to you, being a response). If it was not a response, it was not an example of your definition of NS. If anything, it is an example of organisms "passively waiting for mutations", and the mutation is what provides the novelty (classic Darwin).
 
MATT: The [environmental] pressure didn't occur until some of the bacteria first gained the ability to process Lactose again: suddenly able to process lactose, their population exploded while those that could not process lactose remained about the same. [...] in accordance with the accepted scientific definition of evolution, "A change in the frequency of Alleles from generation to generation," we just witnessed an evolution event.
 
Yes, yes, yes, an evolution event, but environmental pressure did not cause the initial response! The genotype had changed before the explosion, i.e. the mutation proved to be beneficial, and when it did, NS ensured that the change survived and flourished. Classic Darwinian evolution.-MATT: If you don't accept that definition, I can at least tell you that it exists in two textbooks I remember from undergrad, as well as in professional writings from Pigliucci and Miller.-I have not commented on this definition of evolution. Our dispute is over your definition of NS. -MATT: I don't see where NS as I understand it excludes random phenomenon at all...-Your definition specifies only a response to environmental pressure. I repeat: how can a random mutation be a response?-MATT: Here's the issue; Evolution by NS explains by my estimation about 70% of biological phenomenon. At present there is not an existing theory that matches it etc. etc. -There is absolutely no disagreement between us here, and never has been, except when you substitute NS for evolution. So let me finish with a sensational suggestion, for we are all independent thinkers, are we not? Here is a compromise that will end forever this sequence of misunderstandings between us: let us call it The Theory of Evolution by Adaptation, Innovation and Natural Selection.-***********-A note for newcomers to this forum, concerning references to age and shrinking brains: David, Matt and I have been arguing furiously for several years now, and although unfortunately we have never met, we are the best of friends!-David is older than me, and shrinkage is certain to be more advanced. However, it is only fair to point out that the effects of shrinkage in relation to the brain capacity of others will be proportionate to the brain capacity with which one started.