A large bunch of this is crap yes, but still I think (my opinion) there is probably some truth behind a few of the issues. A Slashdot-referred article should have proper references.
About blue eyes. Previously I thought the reason they (and blond hair and fair skin) is common in Scandinavia, is that at high latitudes, the skin has a lower level of melanin (pigment) in order to allow more efficient Vitamin D synthesis from sunlight. At high latitudes, there is less sunlight, so the process needs to be more efficient. And the color of the iris would normally have the same relative level of melanin as the rest of the skin and hair. But this does not seem to be the case - merely having blue or brown eyes does not seem to result from differences in melanin content, see article below. However, I think in the south, to my eye almost all brown eyes are darker than the brown eyes here.
J Ocul Pharmacol. 1992 Spring;8(1):35-42.
Quantitative determination of the melanin contents in ocular tissues from human blue and brown eyes.
Menon IA, Wakeham DC, Persad SD, Avaria M, Trope GE, Basu PK.
Department of Ophthalmology, University of Toronto, Ontario, Canada.
This paper deals with our findings on the quantities of melanin in the tissues from blue and brown eyes. The amount of melanin in the iris, ciliary body and retinal pigment epithelium-choroid was separately determined. The results are expressed as the amount of melanin in mg tissue as well as the amount of melanin in the whole tissue. The results showed that there was no statistically significant difference between the melanin content of the iris in blue and brown eyes. However the ciliary body and retinal pigment epithelium-choroid from brown eyes had more melanin than the corresponding tissues from blue eyes. Blue and brown eyes with higher colour intensity had more melanin than the corresponding eyes with lesser intensity of colour. It is suggested that the differences between brown and blue eyes in their melanin content may have relevance to the pharmacokinetics of drugs that bind to melanin. This would mean that the larger amounts of melanin would decrease the initial levels of the drugs and would increase the drug levels after prolonged periods.
Slashdot Mirror
LONGER yes, but the intensity is much less so doesn't trigger vitamin D synthesis as easily.
About blue eyes. Previously I thought the reason they (and blond hair and fair skin) is common in Scandinavia, is that at high latitudes, the skin has a lower level of melanin (pigment) in order to allow more efficient Vitamin D synthesis from sunlight. At high latitudes, there is less sunlight, so the process needs to be more efficient. And the color of the iris would normally have the same relative level of melanin as the rest of the skin and hair. But this does not seem to be the case - merely having blue or brown eyes does not seem to result from differences in melanin content, see article below. However, I think in the south, to my eye almost all brown eyes are darker than the brown eyes here.
http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retri eve&db=PubMed&list_uids=1402293&dopt=Citation
J Ocul Pharmacol. 1992 Spring;8(1):35-42.
Quantitative determination of the melanin contents in ocular tissues from human blue and brown eyes.
Menon IA, Wakeham DC, Persad SD, Avaria M, Trope GE, Basu PK.
Department of Ophthalmology, University of Toronto, Ontario, Canada.
This paper deals with our findings on the quantities of melanin in the tissues from blue and brown eyes. The amount of melanin in the iris, ciliary body and retinal pigment epithelium-choroid was separately determined. The results are expressed as the amount of melanin in mg tissue as well as the amount of melanin in the whole tissue. The results showed that there was no statistically significant difference between the melanin content of the iris in blue and brown eyes. However the ciliary body and retinal pigment epithelium-choroid from brown eyes had more melanin than the corresponding tissues from blue eyes. Blue and brown eyes with higher colour intensity had more melanin than the corresponding eyes with lesser intensity of colour. It is suggested that the differences between brown and blue eyes in their melanin content may have relevance to the pharmacokinetics of drugs that bind to melanin. This would mean that the larger amounts of melanin would decrease the initial levels of the drugs and would increase the drug levels after prolonged periods.