calvin
09-18-2006, 04:10 PM
I’ve been reading this:
http://wysinger.homestead.com/science.html
“The work suggests that the skin-whitening mutation occurred by chance in a single individual after the first human exodus from Africa, when all people were brown-skinned”
How is it possible to tell if such a genetic difference was due to a “mutation” and is not simply evidence of intrinsic difference?
“The work raises a raft of new questions -- not least of which is why white skin caught on so thoroughly in northern climes once it arose. Some scientists suggest that lighter skin offered a strong survival advantage for people who migrated out of Africa by boosting their levels of bone-strengthening vitamin D; others have posited that its novelty and showiness simply made it more attractive to those seeking mates”
Why is it not possible that the “mutation” occurred the other way around? If chimps are our closest primate relatives and chimps have white skin, wouldn’t it be more likely that black skin was the result of a genetic mutation?
“Although precise dating is impossible, several scientists speculated on the basis of its spread and variation that the mutation arose between 20,000 and 50,000 years ago. That would be consistent with research showing that a wave of ancestral humans migrated northward and eastward out of Africa about 50,000 years ago”
How does the spread and variation of a gene determining white skin colour provide evidence for the temporal location of a race?
“The work raises a raft of new questions -- not least of which is why white skin caught on so thoroughly in northern climes once it arose. Some scientists suggest that lighter skin offered a strong survival advantage for people who migrated out of Africa by boosting their levels of bone-strengthening vitamin D”
If skin colour is related to vitamin D production why are the indigenous inhabitants (San?) of the Kalahari less black than East and West Africans?
“Others have posited that its novelty and showiness simply made it more attractive to those seeking mates”
Once white skin had achieved a certain critical mass it would no longer be a novelty. Wouldn’t the resultant black/white chromatic dynamic ultimately result in a brown skinned population?
"In Africa people are much darker than they need to be for UV protection, so to me that screams sexual selection," Dr. Shriver said. Black skin, in other words, may have been favored by men and women in sexual partners, just as pale skin may have been preferred in sexual partners among Europeans and Asians”
Same as the above, why would a variation continue to be attractive once it had ceased to be a variation and had become a dominant trend?
“In Africa people are much darker than they need to be for UV protection”
Does there come a point where the intensity of skin pigmentation is detrimental to vitamin D production?
http://wysinger.homestead.com/science.html
“The work suggests that the skin-whitening mutation occurred by chance in a single individual after the first human exodus from Africa, when all people were brown-skinned”
How is it possible to tell if such a genetic difference was due to a “mutation” and is not simply evidence of intrinsic difference?
“The work raises a raft of new questions -- not least of which is why white skin caught on so thoroughly in northern climes once it arose. Some scientists suggest that lighter skin offered a strong survival advantage for people who migrated out of Africa by boosting their levels of bone-strengthening vitamin D; others have posited that its novelty and showiness simply made it more attractive to those seeking mates”
Why is it not possible that the “mutation” occurred the other way around? If chimps are our closest primate relatives and chimps have white skin, wouldn’t it be more likely that black skin was the result of a genetic mutation?
“Although precise dating is impossible, several scientists speculated on the basis of its spread and variation that the mutation arose between 20,000 and 50,000 years ago. That would be consistent with research showing that a wave of ancestral humans migrated northward and eastward out of Africa about 50,000 years ago”
How does the spread and variation of a gene determining white skin colour provide evidence for the temporal location of a race?
“The work raises a raft of new questions -- not least of which is why white skin caught on so thoroughly in northern climes once it arose. Some scientists suggest that lighter skin offered a strong survival advantage for people who migrated out of Africa by boosting their levels of bone-strengthening vitamin D”
If skin colour is related to vitamin D production why are the indigenous inhabitants (San?) of the Kalahari less black than East and West Africans?
“Others have posited that its novelty and showiness simply made it more attractive to those seeking mates”
Once white skin had achieved a certain critical mass it would no longer be a novelty. Wouldn’t the resultant black/white chromatic dynamic ultimately result in a brown skinned population?
"In Africa people are much darker than they need to be for UV protection, so to me that screams sexual selection," Dr. Shriver said. Black skin, in other words, may have been favored by men and women in sexual partners, just as pale skin may have been preferred in sexual partners among Europeans and Asians”
Same as the above, why would a variation continue to be attractive once it had ceased to be a variation and had become a dominant trend?
“In Africa people are much darker than they need to be for UV protection”
Does there come a point where the intensity of skin pigmentation is detrimental to vitamin D production?