Natural Selection (Evolution)

by dhw, Monday, August 01, 2011, 19:33 (4861 days ago)

Matt, there is unfinished business 'twixt thee and me. Just before you went on holiday, you gave us your definition of Natural Selection. I replied on 28 July at 15.51(under "Science vs Religion") but would prefer it if we started a new thread. I'm therefore reproducing my reply here. -MATT: The definition I use is the one I was taught and used in the laboratory; "Natural Selection is the process by which an organism undergoes environmental pressure, and responds to that pressure in its genotype."-This is a truly shocking revelation, partly because many of the disagreements we've been having are due to the fact that your "understanding of Natural Selection has thus far been drastically different from everyone on this forum." Too right it has. The above seems to me to be far more appropriate as a definition of adaptation (which I would link to microevolution and epigenetics). I have at least a dozen reference books ... general dictionaries, specialist dictionaries and encyclopedias, many of them published within the last ten years ... not one of which offers anything but the standard definition I quoted on July 12 at 22.37. An Oxford Science Encyclopedia (2003) for schools describes it in the same way, the consultant editor being one Richard Dawkins. May I therefore ask you the following questions:-1) What name do your "professional scientists" give to the process by which those plants and animals best suited to a particular environment are most likely to survive and breed? -2) Do please give me a reference that authenticates your claim that "professional scientists" no longer use the Darwinian definition.-3) What does the word "selection" have to do with your definition?-I shall now condense and revise the reply I drafted last night concerning the Barry Hall experiment, since most of the disagreements are explained by your definition. You described this experiment as "a perfect example of a bacteria gaining a completely novel protein by entirely random mutation", and as "an example of creation of a new function by random mutation and natural selection only." If an organism responds to environmental pressure in its genotype, how can the new protein be attributed to "random" mutation? In other words, how does random change constitute a response? Also you emphasize that the beta-lactamase function was NOT integral to the species, and "several generations continued with the bacteria moving along just fine." In that case, what was the environmental pressure to which the bacterium responded? Either this was a random mutation or it was a response to the environment, but you seem to be trying to have it both ways, which makes no sense to me. -You have argued in any case that you see "no reason at all to assert that Natural Selection isn't enough." Even if we were to accept your definition, it is clear that NS is far from enough. It does not explain innovations such as sex, flight, sight (i.e. totally new organs, which I would associate with macro-evolution), it excludes random mutations (according to my interpretation of "random"), and as it is worded, it doesn't even indicate any kind of change, let alone the all-important factor of survival, without which the organism's response will be of very little use!
 
Please don't get the wrong idea here. I'm telling you what I don't understand, and why. A clear explanation may prevent a lot of future misunderstandings.