RE: [asa] Of motes and beams

Thanks for the explanation. I am raising questions not questioning. Surely, one can have a system with simple atoms that "evolve" into complicated molecules as the system evolves in time from some initial conditions, which can be accomplished in short time scales. Are the computer simulations of evolution you mention of that type? I will have our library order "Darwin in the Genome" by Lynn Caporale.

Moorad

________________________________

From: Iain Strachan [mailto:igd.strachan@gmail.com]
Sent: Tue 7/18/2006 9:52 AM
To: Alexanian, Moorad
Cc: Asa
Subject: Re: [asa] Of motes and beams

On 7/18/06, Alexanian, Moorad <alexanian@uncw.edu> wrote:

        The example is that humans have built-in abilities that can be used in new situations without meaning that they have evolved. It is a question of time scales. If a system can readjust itself to new circumstances in short periods of time, that cannot be called evolution.

Can you explain why you say this? It's evolution if the principal mechanism of adjustment is mutation + natural selection. The timescale is irrelevant. You can make evolution happen in a computer simulation that runs in a fraction of a second, and it's still an evolutionary process. Admittedly the valuable applications of genetic algorithms are few and far between, but they do exist. I agree it doesn't _prove_ humans have evolved, but that wasn't what I was trying to prove - all I was saying is that you can't per se call evolution a bad thing, or say it has a "bad track record". If it didn't go on in your immune system you'd be dead very quickly, as tragically, victims of AIDS find out.

For what it's worth, I was extremely sceptical about evolution of different species for a long time, based on my own experience with genetic algorithms, and how difficult it is to get them to solve any worthwhile problems. However, I'm reading a very helpful book at the moment that goes a long way towards answering the questions I had, namely "Darwin in the Genome" by Lynn Caporale. It is also refreshing that Caporale doesn't use her science as an excuse to bash religion (and explicitly says so). One of the key limitations of genetic algorithms appears to be that mutation is completely random (ie equally likely to strike at any point). However, a simple observation from Caporale's book (that the four bases A,C,G and T are slightly different), leads to the fact that mutation isn't equally likely everywhere - in fact there are localised hot spots where lots of mutations occur and areas where very few mutations occur. This is precisely what is going on in antibody evolutio!
 n - the bit that binds on to the antigen mutates rapidly, and the fixed bit of the antibody (that sends some sort of signal for the rest of the sytem to act, as I recall) doesn't mutate. But the mutation process happens exactly as it does over generations - by inexact copying when a DNA molecule replicates itself. There is essentially no difference here between this type of replication, and when DNA replicates to produce sperm or egg cells, in that inexact copying gives rise to mutations.

Iain

        Of course, the time scale of readjustment is of the order of the lifetime of the system.

        Moorad

        
________________________________

        From: Iain Strachan [mailto:igd.strachan@gmail.com]
        Sent: Tuesday, July 18, 2006 3:44 AM
        To: Alexanian, Moorad
        Cc: Vernon Jenkins; George Murphy; Don Nield; asa@calvin.edu

        
        
        Subject: Re: [asa] Of motes and beams

        On 7/18/06, Alexanian, Moorad <alexanian@uncw.edu> wrote:

        I am not sure I understand. When a human encounters a new mathematical problem and is able to develop a solution to it with the prior information he/she has about mathematics, can we say that the individual evolved or just that the human brain has the ability to "figure out" new situations with already existing elements?

        I wouldn't say that the solving of a mathematical problem, a sequence of logical steps based on some informed guesses, bears any resemblance to the evolutionary processes by which the immune system works. Unless you solve mathematical problems as in a cartoon I once saw depicting Einstein's blackboard, which had three lines on it: E = ma^2 (crossed out) E = mb^2 (crossed out) E = mc^2 (tick). No-one solves maths problems like that so to bring it up is an irrelevancy.
        
        Iain

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