Because blue eyes are found mainly in people of European descent and the percentage of world population of European descent has dropped quite a bit with the population booms in Asia and Africa.
Ok, but that’s mostly because you use that particular cutoff point, European decended populations just have gone through the demographic transition earlier and their share of world population is similar to what it was in 1750. It has nothing to do with any selection against blue eyes in the usual sense.
Well that brings us back to the question of what you mean by “natural selection” which you defined earlier as
changes in the frequency of genes not planned by wise and well-intentioned humans.
It sounds like you are limiting natural selection to frequency changes which are a direct result of the effects of the genes in question. Is that right?
That wasn’t me, and I said “in the usual sense” specifically because the context was Will’s (unusual) definition.
I differentiate between selection and genetic drift like usually done and the case of blue eyes would be an example of the latter. I think the difference is normally described as selection being a consistent non-random effect. Personally I’d describe it as an effect on the relative frequencies caused by the presence of the gene.
That wasn’t me, and I said “in the usual sense” specifically because the context was Will’s (unusual) definition.
I apologize for confusing you with him.
Personally I’d describe it as an effect caused by the presence of the gene, which genetic drift isn’t.
Okay, well I would still guess that natural selection is going at a good clip these days. For example it seems pretty likely that the gene for twinning is spreading pretty fast.
Because blue eyes are found mainly in people of European descent and the percentage of world population of European descent has dropped quite a bit with the population booms in Asia and Africa.
Ok, but that’s mostly because you use that particular cutoff point, European decended populations just have gone through the demographic transition earlier and their share of world population is similar to what it was in 1750. It has nothing to do with any selection against blue eyes in the usual sense.
Well that brings us back to the question of what you mean by “natural selection” which you defined earlier as
It sounds like you are limiting natural selection to frequency changes which are a direct result of the effects of the genes in question. Is that right?
That wasn’t me, and I said “in the usual sense” specifically because the context was Will’s (unusual) definition.
I differentiate between selection and genetic drift like usually done and the case of blue eyes would be an example of the latter. I think the difference is normally described as selection being a consistent non-random effect. Personally I’d describe it as an effect on the relative frequencies caused by the presence of the gene.
I apologize for confusing you with him.
Okay, well I would still guess that natural selection is going at a good clip these days. For example it seems pretty likely that the gene for twinning is spreading pretty fast.