Sorry, it just gets more confusing for me...

bernard Wrote:
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> This is NOT a society permission question. Whiter
> people will have more stillbirths because of the
> amount of solar radiation and therefore will have
> fewer descendants-- exactly what "reproductive
> advantage" means. Indeed natural selection applies
> to humans not just to other organisms.

The layman's question would be whether this means that it is potentially dangerous for lighter skinned people to live in equatorial zones.

>
> You can see for yourself how much variation there
> is in human skin color. Look at the range from
> Swedish blondes to the darkest Nigerians and all
> the variations in between. All this range comes
> from different combinations of possibly 8 genes.
> Look at how dark even lighter colored people can
> get if exposed to enough sunlight, i.e. sun
> tanned.

This idea of random skin pigmentation is what wireless and i are having problems understanding. Clearly, it isn't random. White parents will rarely give birth to a black child. It is difficult to believe that it is not somehow genetic and inherited. Are you saying if were to live in Africa, my descendents will be darker simply though the recombinations of the 8 genes? Can a Swedish blond become a dark Nigerian through this process over thousands of years?

>
> There are no taxonomic relationships-- remember
> there are no races-- I'm just pointing out in fact
> how useless skin color is for classifying since it
> is so subject to adaptation to degrees of
> sunlight. The reason it takes a while is that it
> is not a severe challenge (that is why I went to
> DDT as an example because of its strong
> selectivity). An example in humans, is malaria.
> Malaria is such a severe selective factor (causes
> so much mortality) that any adaptation that
> provides some relief spreads through the
> population much faster. For example, sickle-cell
> gene in Africa reached some 30% of the population
> of Cameroon in about 1000 years.

Ok, so is it right to say that it is possible to discern from racial characteristics the approximate geographical or latitudinal range of one's ancestry? You see, most people would say that this info. equates to taxonomic relationships: presumably if your ancestors lived in an equatorial zone for 10'000 yrs, they shared the same gene pool with those who also lived there. From what you're saying, an extreme and unrealistic example may be the ancestors of a Nigerian who lived in Scandinavia for 10'000 years, migrated to Africa and lived for just as long, and then migrated to Scandinavia and lived for another 10'000 yrs before returning to Africa. Clearly, racial characteristics will not show the first three or four migrations, and will only indicate that last 10'000 years of adaptations. Therefore, racial characteristics do not have taxonomic value. However, this is a highly unrealistic example. Are genetic tests showing that this is indeed the problem, if not the potential problem?



PS. the questions i ask in my posts are my attempts to understand what you're saying and none of them are debating your comments if you understand what i mean....