Math of evolution
David Campbell (bivalve@mailserv0.isis.unc.edu)
Wed, 21 Oct 1998 10:55:11 -0400
>At 07:58 PM 10/20/98 -0500, Glenn wrote:
>>Evolutionary theory sure does use math. Have you never heard of population
>>dynamics, the logistics equation, Hardy-Weinberg, the equations of
>>chemistry, and others. I am sure that the biologists could do a better job
>>than I. The assertion that biology doesn't use math is ... well, wrong.
>
>Maybe so, Glenn, but have you ever examined the consequences of say, for
>example, Hardy Weinberg for evolution? A colleague of mine at Cal Tech
>told me one time that Hardy Weinberg was the death knell of evolutionary
>theory. For example when Arthur in his book on the Origin of Body Plans,
>wants to show how a mutation can be fixed in a population, he chooses a
>dominant mutation to work the math with, even though he admits that the
>probability of such a mutation is vanishingly small. Why? Because the
>equations dont produce the desired results when he uses the same parameters
>in Hardy Weinberg with a recessive mutation. It won't happen, so such
>things as founder effect had to be invented to make anything happen. But
>for it to happen in the founder population, the appropriate genes have to
>be there, and thr probability of that is also calculable, and is the same
>order as the pprobability for the fixing of the recessive mutation in the
>population. So the math that biologists do have doesn't always help
>evolutionary theory.
>Art
>http://biology.swau.edu
Actually, almost any mutation with any effect will be somewhere between
dominant and recessive, depending on how the gene operates and how closely
you look (e.g., allozymes).
The probability of any one gene being selected by the founder effect is
small, but the probability that the founder has some genes not typical of
the whole population is quite large. The founder effect can be observed in
many modern-day cases, such as the blue people in eastern Kentucky, most
domesticated varieties of organisms, etc.
David C.