...
Post A Reply
my profile
|
directory
login
|
register
|
search
|
faq
|
forum home
»
EgyptSearch Forums
»
Deshret
»
European nations established only from Medieval times - whites are very new to Europe
» Post A Reply
Post A Reply
Login Name:
Password:
Message Icon:
Message:
HTML is not enabled.
UBB Code™ is enabled.
[QUOTE]Originally posted by xyyman: [QB] Mike. If the Euro’s evolved in the Asian steppes then they should be of the same hue as the Asians. The northerners are really really really white. Here is some interesting stuff: [i] While skin tanning is often most noticeable on light complexioned people, even those with very dark brown skin can tan as a result of prolonged exposure to the sun. Some Northwest Europeans have substantially lost the ability to tan as a result of relaxed natural selection. Their skin burns and peels rather than tans. This is due to the fact that they produce a defective form of a skin protein (melanocortin-1 receptor or Mc1r) which is necessary for the production of melanin. They are at a distinct disadvantage in tropical and subtropical environments. Not only do they suffer the discomfort of readily burning, but they are at a much higher risk for skin cancer. The same is true of albinos. People who live in far northern latitudes, where solar radiation is relatively weak most of the year, have an advantage if their skin has little shielding pigmentation. Nature selects for less melanin when ultraviolet radiation is weak. “”Such a non-random distribution pattern of human skin color was predicted by Constantin Wilhelm Lambert Gloger, a 19th century German zoologist. In 1833, he observed that heavily pigmented animals are to be found mostly in hot climates where there is intense sunshine. Conversely, those in cold climates closer to the poles commonly have light pigmentation. The relative intensity of solar radiation is largely responsible for this distribution pattern.”” “” Previous studies of human skin color have shown a strong relationship between skin color and distance from the equator, which has been interpreted as a link between skin color, latitude, and the intensity of ultraviolet radiation. The underlying assumptions are that UV radiation is greatest at the equator and that it diminishes with increasing latitude to the same extent in both the Northern and Southern Hemispheres. The standard analysis of human skin color is based on these assumptions, such that skin color is assumed to be darkest at the equator, and the decrease of skin color with latitude is assumed to be the same in both hemispheres. A nonlinear piecewise regression model was developed to test these assumptions and applied to mean skin reflectance data from 102 male samples and 65 female samples from across the Old World. The results indicate that human skin color is darker in the Southern Hemisphere than in the Northern Hemisphere at equivalent latitude. Recent research shows that UV radiation is higher in the Southern Hemisphere than in the Northern Hemisphere at similar latitude. This difference, relating to astronomical and climatic conditions, may have existed in the past at different times and perhaps influenced the evolution of human skin color. “” http://cat.inist.fr/?aModele=afficheN&cpsidt=1567631 [/i] [/QB][/QUOTE]
Instant Graemlins
Instant UBB Code™
What is UBB Code™?
Options
Disable Graemlins in this post.
*** Click here to review this topic. ***
Contact Us
|
EgyptSearch!
(c) 2015 EgyptSearch.com
Powered by UBB.classic™ 6.7.3