On Sat, 27 Sep 2003 21:27:45 +0000 (UTC), "Representative Trantis"
 wrote:

>Why is it so frowned upon to propose the idea that an animal can get worse,
>before it gets better. It is not inconcieveable that an animal could get
>worse at doing a job, but because there are no predators, etc, it doesn't
>die out.
>
>Or is it the case that in the wild a creature will only get enough food to
>be able to survive, so must be the best it can be at it's job?
>
>[moderator's note: I have thought about this myself: the adaptationist
>ideal is that mere adequacy must be optimized -- that is, one must be
>optimal just to persist. Is this true? - JAH]
>

There is absolutely no "drive for perfection" or optimality in
evolution.  In fact, it is generally true that you only have to be
good enough to get by. The problem is competition -- if other
organisms outcompete you for resources -- food, habitat, whatever,
then you lose and are gone.  However, if you have no competition or
you can outcompete in other ways, then that is not a consideration.

Consider the innumerable instances of really stupid design even in
humans.  Our backs go out incredibly frequently, our pelvis and birth
canal is marginally too small to accomodate our large heads, our jaw
really isn' quite big enough to hold all our teeth, our eyes are built
inside out and our kidneys are built exactly backwards to enable us to
survive in dry or salty environments.  

There are animals with keener vision and keener hearing over a far
wider range of frequencies.  Our sense of smell is far worse than that
of most mammals.  And there are innumerable animals with much worse
hearing and vision than ours.  There are numerous cases of organisms
in isolated habitats (flightless birds on islands, marsupials in South
America of Australia, a tremendous number of organisms on Madagascar)
that have serious problems competing with placental mammals introduced
by humans.  And invasive species take over entire habitats because the
native species can't compete. 

Organisms that live in special habitats lose all kinds of abilities.
Cave animals that live in constant darkness eventually tend to lose
their vision (I mean the species does, not the individual!)  Parasitic
animals are highly modified. You can argue that these adaptations are
a way of becoming "more perfect" for their new environment.  But they
are also becoming distinctly "inferior" to survive in their original
environment.  Is that getting "better" or getting "worse"?

No, organisms are by no means "ideal" or "perfect" or
"optimized".
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