It's a convenient device of language to think of it that way, but one
must be careful not to take the idea too literally...
> One divergent opinion was weather a gene that codes for extra longevity
> is good or evil? (in terms of reproductive success)
>
> My opinion is that it is good. If one organism lives longer, it has a
> higher chance to produce more offspring and therefore it is a good gene.
> It's as simple as that.
...like that. Good and bad only exist where there is an agent of
conscious choice, and genes are not conscious. Their "selfishness"
is simply a way to describe the effect of replication in terms that
make some phenomena easier to understand. But the effect itself is
merely an after-the-fact effect of whatever changes happen to occur.
A gene can't judge ahead of time what would be good or bad; they
simply are what they are, change when they change, and the ones left
standing are here because they /were/ good for the environment in
which they replicated. In the case of most higher animals on Earth,
the first ones probably had no use for death, but by chance, one
happened to mutate into a form that died, and that one was more
successful at reproducing than those who didn't /in the environment
of that time/, because spending limited resources on older beings--
perhaps with too many copying errors in their DNA or some other
fitness problem--was more costly than simply killing them off and
saving those resources for younger breeders.
It is quite possible that a species similar to Homo Sapiens, but
immortal, would be successful in today's environment. But unless
that mutation actually happens, and the two forms compete for
a few millenia, there's no reason for it to happen. "If it ain't
broke, don't fix it" is a popular principle of evolution.
> If, indeed, a gene that codes for extra longevity is an advantage, why
> isn't it present?
Again, the point of view is backward. The question is, since
longevity isn't the current state of affairs, why was it selected
against (if it ever existed in the first place)?
-- Lee Daniel Crocker <lee@piclab.com> <http://www.piclab.com/lcrocker.html> "All inventions or works of authorship original to me, herein and past, are placed irrevocably in the public domain, and may be used or modified for any purpose, without permission, attribution, or notification."--LDC