Why did caucasian people evolve to have white skin?

Question

Hi I'm wondering kind of a stupid question but does anyone know why caucasians have evolved to have white skin. Because I know that people orginally started out in africa and that the first people had dark skin to protect themselves from the sun. But it doesn't make sense to me that just because people move to less hot places they would evolve to have lighter skin. So does anyone know why this happend? This question isn't racist and please don't leave any stupid answers.

Answer 1

Except for the Inuit people - who evolved from the Asiatic People and migrated on the land bridge to Alaska and Greenland, etc - the darker people could have evolved from moving to colder climates because the colder the climate - the lighter the people became. Melanin is a defense mechanism from UV rays - that is why lighter- skinned people tan. Where it was cold all the time- like Norway, Greenland and Finland - the peoples most probably became paler to adapt to the cold. Example - I am mixed - Black,Cherokee, and White - and during the summer my skin has a reddish hue - during the winter, it has more of a paler yellowish cast to it - so I can see skin color changing over years of evolution in the colder climes.

The retention of the ancestral trait at the equator is due to natural selection for melanin pigment production which serves to protect the body from harmful UV rays (Jablonski 2006). Notably, given that hair is a part of the skin, the retention is also analogous to that which occurred for Natural afro-hair prior to pre-Holocene admixture events among people who settled in India and Australia. However, certain evidence suggests that, unlike skin color, Afro hair ceased to be under strong selection once dark skin arose ~1 million years ago (Harding 2000) (rather, it remained as a vestigial trait among Africans, Andamanese, and Melanesians and changed to straight in the north for adaptive reasons--see hair texture). In fact, dark skin is so selectively advantageous at the equator that initially light skinned native Americans who migrated to Mexico and/or South America experienced renewed selective pressure towards the evolution of dark skin. Here is a quote from Wikipedia :

"According to (Norton et al., 2006), light skin observed in Europeans(With deep Red and/or yellowish skin tones.), non-Indian Southeast Asians, East Asians and North Africa (Maghreb) is due to independent genetic mutations in at least three loci. They concluded that light pigmentation is at least partially due to sexual selection, however Jablonski postulates that the predominant reason revolved around the facilitation of vitamin D production in northern Eurasia (see hair texture)."

Answer 2

Desk jobs...

that would almost be my serious answer if I fully believed in evolution

Answer 3

Human skin color changes across the north-south direction. People living in the tropical area needs darker skin to protect from the high radiation of the sun, but people living in far north needs a white (more permeable) skin to produce enough vitamin D. As people migrated to the north, the relatively light colored people were more fit to survive and procreate in those low sunshine area. Thats why people of north has developed lighter skin after generations of evolution.

Answer 4

We humans did start out in Africa, and we were all black.

The out of Africa migration was done during the first half of the Pleistrocence period. It was a time of ice ages, when sea levels dropped significantly and there was increased rainfall in many regions. At the same time Homo erectus was making stone tools and was able to use fire. The question of his being able to create fire has not yet been answered. Given the favorable climate and the increased skills to control his environment, Homo erectus spread out of Africa.

As for skin color:

"In their analysis of human evolutionary history, Jablonski and Chaplin concluded that modern humans most likely evolved in the tropics, where they were exposed to high UV levels. But as they moved into regions away from the equator, where UV levels are lower, humans became fairer so as to allow enough UV radiation to penetrate their skin and produce vitamin D, the "sunshine vitamin," also obtained from eating fish and marine mammals. Vitamin D is essential for maintaining healthy blood levels of calcium and phosphorous, and thus promoting bone growth.

Skin color, according to Jablonski and Chaplin, basically becomes a balancing act between the evolutionary demands of photo-protection and the need to create vitamin D in the skin.

One of the important implications of Jablonski and Chaplin's work is that it underlines the concept of race as purely a social construct, with no scientific grounds. DNA research has shown that genetically all humans, regardless of skin color and other surface distinctions, are basically the same. In an April 2001 article titled, "The Genetic Archaeology of Race," published in the Atlantic Monthly, Steve Olson writes "the genetic variants affecting skin color and facial features are essentially meaningless —they probably involve a few hundred of the billions of nucleotides in a person's DNA. Yet societies have built elaborate systems of privilege and control on these insignificant genetic differences."

http://ngm.nationalgeographic.com/ngm/02...

"Before the mass global migrations of people during the last 500 years, dark skin color was mostly concentrated in the southern hemisphere near the equator and light color progressively increased further away, as illustrated in the map below. In fact, the majority of dark pigmented people lived within 20° of the equator. Most of the lighter pigmented people lived in the northern hemisphere north of 20° latitude."

http://anthro.palomar.edu/adapt/adapt_4....

Australopithecus Images

http://hannover.park.org/Canada/Museum/m...

http://www.kriscot.com/australo.htm

http://www.kriscot.com/austral2.htm

Lucy

http://hannover.park.org/Canada/Museum/m...

Answer 5

I have heard that it was a gene mutation that caused all of that. I can't remember the source from college but I got that from an anthropology class that was studying pigmentation in the world and the evolution of the various colors of human beings.