From: ian@inf.ethz.ch (Ian)
Subject: Re: evolution a fractal?
Reply-To: badcoe@uk.ac.bristol.bsa or badcoe@ezrz1.vmsmail.ethz.ch
Organization: Dept Biochemistry, University of Bristol, UK
Date: Mon, 5 Oct 1992 10:05:20 GMT

In article <92278.013343GE0QC@CUNYVM.BITNET> <GE0QC@CUNYVM.BITNET> writes:
>In reseponse to Ian:
>
>Evolution is caused by mutations.
>Mutations can fallinto three categories:
>A beneficial mutationin which the organism benefits from the mutation.
>  harmful mutation, in which the organism suffers detrimental effects.
>  nonimpacting mutation, in which the mutation does not produce the above
>    effects, but might      produce an effect with other mutations in later
>    generations.
>But to simplify let's say a mutation is either beneficial or harmful.
>To simplify further, consider evolution to be the result of iterations
>of mutations that have beneficial results.
>(remember this is a simplified simplification)
>A fractal is produced with the iterations of a set of rules.

This is true.

>In evolution the the set consists of one rule: a benefecial mutation.

This is too simple to mean anything.

There is one way in which evolution is at least heirarchic (I've no idea 
whether it's fractal) and that is the different levels at which selection can 
occur:

i) The level of DNA

ii) The level of the cell

iii) The level of the organism (this is what most people think of)

iv) The level of the population

These levels do not act in accord with each other, for example at level (i)
there are genes which code for their own duplication, these genes are of no
use to the organism and yet they proliferate because they can duplicate faster
than selection (at level iii) removes their hosts.

Similarly, selection at level (ii) produces cancers (which is one of the 
reasons that cancer is so hard to cure) and selection at level (iv) can produce
a (for want of a better word) 'society' capable of acting against it's members
(for example herds (sp?) of various species, where only the alpha-male gets
to reproduce).

>Look at the world about you, symmetry reigns.

I assume you are talking about the structures of organisms ?

This is more to do with the techniques that evolution has produced for the
generation of structure than to the structure of evolution itself.  Many parts
of developemental biology do consist of repeatedly applied rules (most 
strongly seen in plants) and do produce fractal structures.

I'm sorry if I've been a bit flamey but I get very annoyed when I see people
(apparantly) being mystical about evolution.  It's a very simple phenomenon
with very complicated affects.  Yes, it's something like a fractal in this
respect.  ***NO***, the previous sentence isn't useful in any way.  It doesn't
help us understand evolution and it is very dangerous in that it makes us
tend to ignore the mechanistic aspects of evolution and start looking for
underlying patterns in things which are not related.

There's only one way to understand evolution, and that's consideration of the
selection procedure itself.  As long as you:

a) always think in terms of, "What structures will still be here at the end of
   the day ?"

b) remember that you could be wrong about what's being selected

c) don't expect the results to necessarily make (immediate) sense from a 
   human perspective (because when people design something they have to 
   understand it, when evolution produces something it doesn't have that
   constraint)

then you've got general evolution all stitched up!

Of course, specific cases require far more detailed knowledge.

Again, sorry if this is a bit of a flame, also sorry that it strays so far from
Newsgroups: alt.fractals,sci.fractals