Evolution has stopped?
staton at onramp.net
Mon May 1 16:49:48 EST 1995
In article <10708 at raven.ukc.ac.uk>, mjg5 at ukc.ac.uk (ShereKhan) wrote:
> Hiya. Ok, I'm a biochemist undergrad, but I have not been taught and
> probably never will be taught any evolutionary theory more advanced than
> A-level Biology. Darwins ideas make sense to me yes. But the thing is
> I am confused as to whether evolution has stopped now? I mean, many
> scientists agree that Humans have reached the pinacle of their evolution,
> but I think that it may well be the case that maybe the whole of the
> eukaryotic domain has ended its evolutionary process, in terms of the
> characteristics of species being perfect as they are. Can anyone
> put their ideas forward because I find this dilemma quite interesting.
My reading of Darwin and understanding of punctuated equilibrium suggests
that human evolution continues as long as allele frequencies change in the
population and this could (and is) happening in many conditions. Evolution
is not a kind of progression from lower to higher, it only means change.
Successful genotypes continue, unsuccesssful ones are blind alleys.
Consider for example how ozone depletion might affect human populations.
We might see light skin become maladaptive and cancer rates go up for
Europeans while Africans and Asians continue more successfully relative to
Europeans. Or perhaps social circumstances might lead to relatively fewer
numbers of any particular group. In America, we see reproduction rates
lower for European descended peoples than for African descended peoples.
The end result over time is that one population may get absorbed or "die
out" or whatever or the resulting populations have relatively fewer
examples of the unsuccessful, in this case European, genotypes. Or it
could happen the other way. Or it could have nothing to do with current
racial categories but perhaps involved differential rates of reproduction
for people with varying lung capacities or resistance to diseases etc..
Thus human evolution is continuing as long as differential rates of
reproduction of different human genotypes continues. Also, cataclysmic
events, say a meteor that kills 98 percent of humans saving only those in
the most tropical regions would lead to "evolution."
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