Evolution: a different view (Introduction)

by David Turell , Friday, April 22, 2016, 15:47 (3136 days ago) @ dhw


> dhw: I do not see evolution as solely the result of compulsion. As we have said, there was then no need for any advance beyond bacteria, and all that was required was adaptation. Nor do I see why the walk has to be random, and I find the whole “walk” image unconvincing, as I do the “landscape” image. If common descent is true (and I believe it is), then all innovations must take place WITHIN existing organisms, and that means cells must organize their own mutations (in the sense of innovative changes). ....It seems to me that the essay provides no answer to the mysteries of how life and the mechanisms for evolution came into being, or how innovation actually takes place. We know that all the component parts are there, and it is interesting to hear that there are many different ways of reaching the same solution, but that is a far cry from proving that life and evolution were “almost a mathematical inevitability”(though one should note the word “almost”).-I appreciate your taking time to review this article. Here is another assumption of 'ease' or 'facilitation' from giant numbers present in the article:-"Proteins have this property too. Different organisms often possess proteins with the same shape and enzymatic function (phenotype), yet typically these will share no more than 20 percent of their amino acids in common. Using a simple model of protein structures, David Lipman and W. John Wilbur of the National Institutes of Health in Maryland showed in 1991 why this should be so: Their simplified model proteins were linked into extended networks in sequence space that can be traversed by neutral mutations one step at a time. In 2001 this apparent redundancy between protein sequence and phenotype was demonstrated experimentally by Anthony Keefe and Jack Szostak at Harvard University. They set out to look for proteins made from randomly assembled amino acids that could bind to the small molecule called ATP, which is the key energy-storage molecule of living cells. Just about any protein that does useful work, such as transporting other molecules or catalyzing their transformation into new forms, uses ATP as the energy source. ATP-binders are therefore vital components of cells. Szostak and Keefe used a chemical method to assemble 80-amino-acid proteins at random from their component parts, and were able to sift through all the variants that they made to find ones that happened to be aptly shaped to bind ATP.2 They couldn't make anything like the total number of possible permutations of this number of amino acids. But among the tiny fraction (6 trillion) that they did produce, they found four ATP binders. That doesn't sound like a lot, but if there are already four solutions in this incredibly small sampling of the sequence space, there must be an immense number in the rest of the space—about 10^93 of them, the researchers estimated."-I simply think God made His job easier by setting up these patterns. The author thinks 4 out of 6 trillion is an easy find. I don't.