James Tauber wrote:
>
> One thing that has always fascinated me is the number of genotypic mutations
> that need to take place for the phenotype to have a beneficial change. It's
> not as if a single change to the DNA has an immediate benefit. You really
> need somehow to built change-upon-change, each of which has no individual
> benefit, but the whole sequence of changes leads to a benefit. Survival of
> the fittest can't kick in until the benefit does and so a partial sequence
> of changes leading to a benefit would be have no greater chance that one
> that doesn't lead to a benefit.
You guys need to read: "The Selfish Gene" - Richard Dawkins
For instance, every sexual mating actually mixes chromosomes of the
parents by random splices. Because there is so much unused material,
usually genes aren't split but occasionally they are. Sometimes this
produces an unviable zygote, other times the changes are more subtle.
> James
>
> > Three decades ago, Frank Salisbury of Utah State University described the
> > odds this way: "Imagine one hundred million trillion planets, each with an
> > ocean with lots of DNA fragments that reproduce one million times per
> > second, with a mutation occurring each time. In four billion years, it
> would
> > still take trillions of universes to produce a single gene -- if they got
> > lucky."
Hogwash. Genes didn't spring fully formed. Or cells (there's a movie
where the main protagonist decides to believe in God/creation because a
'cell' couldn't have sprung into existance), or even DNA/RNA.
These kinds of computations implying complete knowledge of all
mechanisms and their complexity, obviously not present three decades
ago.
sdw
-- sdw@lig.net http://sdw.st Stephen D. Williams 43392 Wayside Cir,Ashburn,VA 20147-4622 703-724-0118W 703-995-0407Fax Dec2000
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