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Gary wrote:
> Apart from the influence of
reasoning abilities, I suspect that species
> survival would be our strongest instinct.
This is very unlikely on
evolutionary grounds. Instinctive behavior may result in species
survival or it may not. But very special cases apart, there’s no way
for a species-survival instinct to evolve and become fixed in the gene
pool.
The basic problem is that if
there’s a population of organisms that has the characteristic that each
will give up something important to it – its life, its chance to
reproduce, etc. – for the sake of species survival, that population can
be invaded by mutants who are not so disposed. The mutants will be more
successful at staying alive and reproducing, so the ones with a
species-survival instinct ... don’t survive.
Rob
-----Original Message-----
Gary wrote:
>There seems to be more to it
than just surviving and reproducing. We put a
>great deal of effort into protecting and nurturing our progeny. Our
>altruistic tendencies seem to start with our families, working
outward to
>friends, group, community, etc., the tendency weakening along the
way.
I wasn’t as clear as I could be
(or at least as I fondly imagine I could be).
From one angle, differential
reproduction explains everything in evolution – everything that has an
evolutionary explanation, that is. The organism that is typically more
successful at getting its genes into the next generation is – almost
tautologically – the one whose genes are represented in the next
generation. One of the ways that can be done is by installing built-in
drives or behavioral tendencies that tend to result in successful
reproduction. These can include survival, reproduction, nurturing of
offspring, kin-altruism. (Haldane once expressed this by saying that he
wouldn’t give his life for less than two full siblings or eight first
cousins.)
In order for a genetically
installed drive to spread through a species, some very special
circumstances apart, it has to be good for the genes of the organism
that has the drive – that is, it has to increase the probability that
organisms carrying those same genes will be represented in the next
generation relative to alleles in the same population.
It is plausible on general
evolutionary grounds that drives to survive, to reproduce, to look out
for kin and so on can spread through a population in this way. It is not
plausible that any literal species-survival drive can spread in that
way. Of course, it is often the case that genetically installed drives
and other phenotypic characteristics in fact tend toward species
survival, but that’s not why they’re there. They’re there because they
promoted the successful reproduction of the organisms that possessed
them.
