Re[2]: [at-l] Genetics

[saunterer@jimbullard.org (saunterer@jimbullard.org)]

At 12:00 PM 2/8/02 -0500, Bob C. wrote:
>"...Natural selection, often refered to as evolution, does not take place with
>humans anymore (and for quite some time)."
>
>  This strikes me as a very doubtful statement. I doubt if anyone truly knows,
>  but I would be enormously surprised to discover that the same natural forces
>  that affect other creatures doesn't also affect humans.

I think the truth of this depends on your definition of the terms.  If you 
define "natural selection" as a complex process by which the naturally 
evolving biosphere balances itself through preventing reproduction of less 
viable variants within species then I would say that it is true.  For at 
least the last half century humans have found ways of thwarting "natural 
selection" by prolonging the lives of people who would have died too young 
(in prior history) to allow them to reproduce and pass on 'weaker' genes.

The intelligence that allows humans to do this is not part of the natural 
selection process because it does not benefit only to those who possess the 
intelligence.  It prolongs the lives of those who have physical defects 
that would otherwise shorten their lives and/or prevent them from 
reproducing without any reference to whether the beneficiaries have that 
intelligence themselves.   In other words, the intelligence that allows us 
to prolong life does not necessarily contribute to an increase of the 
intelligence in the overall population and the essence of "natural 
selection" is to preserve and increase the prevalence of desirable traits 
(meaning those traits which favor survival of the species).

As terrific as modern medicine is, it tends (at best) to preserve the 
genetic status quo by preserving genes that otherwise would have been 
selected out.  Add to this the fact that we have obliterated some diseases, 
species, etc. because we regarded them as bad for humans without regard to 
their function in the overall ecology.  By doing that we altered the very 
ecology we depend on and diminished our fitness to continue our existence 
within it.  Before anyone accuses me of lack of compassion, the above is 
not a value judgement on the prolonging of life through science and 
medicine.  It is merely my observation on the dilemma that we have created 
for ourselves precisely because we humans are (generally speaking) a 
compassionate species.

Oh Lord, that's way to serious.  I need to take a hike.

sAunTerer