Patrick Elliott <kag### [at] gmailcom> wrote:
> In most of those cases the genes are still there, or the bones "grow 
> together", such that they seem to have disappeared, but haven't, or they 
> are in fact there, in some limited form, but just not obvious on first 
> appearance. Deletion of entire sets of genes, for a limb, and their 
> replacement with something else, instead of just adjusting the size and 
> shape, doesn't happen much.

Genes are, ultimately, rather inefficient at "optimizing" an organism
to adapt to new or changed environments. Parts that are no longer needed
can linger on for thousands, if not even millions of generations.
Structures that still have important functions, but are quite inefficient
at doing those functions (when there would be much better structures that
could do the same job a lot better), may be retained likewise for millions
of generations, for the simple reason that they were there to begin with,
and a complete replacement by slow modification would require changes with
so astronomically low probabilities of happening, that they just don't
happen. Sometimes the vestiges of old organs may happen to be adapted for
new functions, but they will almost invariably be very inefficient at
those functions (which makes sense; they didn't exist for those functions
to begin with, and thus it's no wonder they are not optimal for a
completely different task.)

Evolution is all about compromises. The genetic code is very slow to
change in the right way to do something efficiently. It's more like a
hack job than anything else (it's like there's a "if it works, don't fix
it" principle constantly going on), and remnants of obsolete parts will
linger on, just because genetics can't just get rid of them that easily.
There's no guiding process to drop those off, and thus they will be built
because the genes say they should. There's nothing stopping them, even
after those parts become useless. Thus you get things like blind eyes
that are physically unable to see (in many species that live their whole
lives in darkness) and thus serve no useful purpose whatsoever. But the
useless eyes are still there because the genes say so, even if part of
the resources used to build them have been turned off or allocated somewhere
else.

When you really start to study how genes work, you start seeing that
there is, in fact, no intelligent design behind it. No intelligent
designer, no matter how incompetent, would be so sloppy and so lazy.
A mindless process that's simply the by-product of natural laws is.

On the positive side, genes are a marvelous example of emergent behavior
in nature. Complexity arising from simple rules.

-- 
                                                          - Warp

Post a reply to this message