51–60 of 72 posts
"Nobody 10,000 years ago had blue eyes," Hawks said. "Why is it that blue-eyed people had a 5% advantage in reproducing compared to non-blue-eyed people? I have no idea." Now that's interesting. Any theories?
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Children are have lighter eyes (and everything else) than adults. It's a sign of youth.
Huh? Are you saying Blue is a lighter shade of Brown?
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Except that in practice, it hardly ever happened until very recently. Ethnic groups lived far apart, and those folks who lived near a boundary between two different ethnic groups would hardly ever interbreed with the others (whether that's mostly cultural or a lack of attraction, though, I'm not sure). Even now, it happens surprisingly infrequently.
>and those folks who lived near a boundary between two different ethnic groups would hardly ever interbreed with the others If you are talking about prehistory, how can you know this?
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>and those folks who lived near a boundary between two different ethnic groups would hardly ever interbreed with the others If you are talking about prehistory, how can you know this?
Well, inferring from the observed behaviour of stone-age tribal peoples in historical times.
Races as we know them today didn't exist until fewer than 20,000 years ago, when genes involved in skin pigmentation emerged, Hawks said. 1) This blows my mind -- am I reading it right that there was virtually no variation in skin color 20,000 years ago? I assumed there was always variation in skin pigmentation, with darker skin colors predominating until we expanded into northern latitudes where lighter colors made…
I think the correct statement is as you say in another part of your post: there has always been variation in skin color in the human population. It was geographically segregated (forming "races" in the biological sense) only very recently. And even today there is a lot of variation among individuals in skin color within each continental subpopulation of human beings.
The usual view of evolution of skin color is that the ancestral condition was white skin under dark hair (as we still see in chimpanzees). Then at some unknown time, human ancestors became less hairy, and darker skin pigmentation became necessary. Then as human beings (Homo sapiens) migrated to latitudes with less sunlight (VERY recently) gene frequencies changed again in favor of lighter skin in some areas. (Inuit people are quite dark skinned for people who live near the North Pole and usually wear heavy clothing.)
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According to Gould (a paleontologist). Dawkins, with his gene-centered view of Darwinian evolution, refutes this, explaining that evolution by natural selection is gradual.
>Dawkins, with his gene-centered view of Darwinian evolution, refutes this, explaining that evolution by natural selection is gradual. People say he refutes this. According to him, he never said anything to refute this. In either case, you have to be specific about what "gradual" means. Dawkin's evolution is more gradual than intelligent design, but not so gradual that it is inconsistent with Stephen Gould's claim.
I'm not implying that they have a hostile personal relationship, but their academic disagreements were significant. Examples include the gradual view of evolution, and also Gould's claim of NOMA, which Dawkins (detests).
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Well, inferring from the observed behaviour of stone-age tribal peoples in historical times.
That's a bit vague. Has anyone run the stats on the incidence of cross-tribal sex? And where would they get the data?
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Yes, if by "shade" you mean the color progression that human (and other mammals') eyes make in their development.
But your eyes don't change from blue to brown as they develop, or do they?
"Nobody 10,000 years ago had blue eyes," Hawks said. "Why is it that blue-eyed people had a 5% advantage in reproducing compared to non-blue-eyed people? I have no idea." Now that's interesting. Any theories?
Don't only Caucasians have blue eyes? And aren't they (full disclosure "we" in my case) also the only ones with the mutated version of the gene which controls how much melanin is deposited in skill, hair and... I think also irises? Asians and Africans both have the normal version of the same gene. And melanin has many roles, sun protection being just one, the other is as a structural protein. Just compare how black s…
More than you ever wanted to know about eyes: http://en.wikipedia.org/wiki/Eye_color
Also, this is neat: A 2002 study found the prevalence of blue eye color among Caucasians in the United States to be 33.8 percent for those born from 1936 through 1951 compared with 57.4 percent for those born from 1899 through 1905.[10] Blue eyes have become increasingly rare among American children with only 1 out of every 6 – 16.6 percent which is 49.8 million out of 300 million (22.4% of white Americans) of the total United States population having blue eyes.[33][34] The plunge in the past few decades has taken place at a remarkable rate. A century ago, 80 percent of people married within their ethnic group. Blue eyes, a genetically recessive trait, were routinely passed down, especially among people of Scottish, English, Irish, Welsh, Western and Northern Slavic, and Northern European ancestry.[33][34][35] In the 1930s, eugenicists[citation needed] used the disappearance of blue eyes as a rallying cry to support immigration restrictions. They went so far as to map the parts of the country with the highest and lowest percentage of blue-eyed people.[citation needed]