Why are Europeans the whitest people on the planet?
knol.google.com
knol.google.com
The one presented fact that I'm _not_ totally solid on is, I'm not sure that prehistoric and ancient art are sufficiently solid to provide a date by which we can assume Europeans were white.
http://www.mywire.com/a/Oxford-Encyclopedia-Ancient-Egypt/Ge...
I don't know anything about the other points in the article, but these errors make me doubt their accuracy.
(Note that I have not read this version, nor have I looked at any of the references he's provided - I just noticed the link and briefly scanned through the page)
I guess paler people today in Northern Europe may have either had ancestors who became darker and then lightened (as per the Knol piece) or moved out of Africa before their skin darkened to deal with the UV/Vitamin D issue. From memory, it's been suggested that expansion into Europe was around 50,000 years ago.
Interesting story though - have never read a page on Knol before.
(Perhaps the author is trying to avoid the suggestion that white people are "more highly evolved", which is of course nonsense; it's just different adaptations suited for different environments.)
[Edit: Yes, this comment is probably stupid.]
What do you mean by "more highly"?
We've known for a very long time vitamin D is produced when the skin is exposed to UV light. We've known how important vitamin D is. Northern Europe dark and cold, yep we've known that too for a while.
Innuit get their vitamin D from the seafood based diet, we've also known that too. Northern Europe being unusually warm thanks to the gulf stream, that is also old news.
So the Europeans had adapted to their environment, changed to a grain diet, suddenly had too little vitamin D. This would mean they would increase their vitamin D, but reduces folate, and therefore increase the number of miscarriages?
Seems like a simple way to test if this hypothesis is actually true. Just look at some historic numbers of the number of miscarriages with those diagnoses (these days pregnant women in Europe get folate supplements).
Did the grain-eating D-deficient Baltic-dwellers have to do something else to restore the folate being lost by their lighter pigmentation?
I loved the semi-aquatic-ape theory (that in foraging for shellfish we lost our fur as whales, dophins, hippos did), but I understand that one has fallen from favour.
Most mammals can sprint faster than humans — having four legs gives them the advantage. But when it comes to long distances, humans can outrun almost any animal. Because we cool by sweating rather than panting, we can stay cool at speeds and distances that would overheat other animals. On a hot day, the two scientists wrote, a human could even outrun a horse in a 26.2-mile marathon.
from http://www.nytimes.com/2009/10/27/health/27well.html
More on the Man vs. Horse Marathon. http://en.wikipedia.org/wiki/Man_versus_Horse_Marathon
The nightmare concept of a relentless, unstoppable killer (as in zombie movies and the Terminator) appears to be based on us.
Our bipedalism and big brain from a high protein diet also seem related to this. It seems to have given us our human qualities, yet also feels so very unrelated to those human qualities.
EDIT: Okay, wisdom teeth then. Or teeth in general, which are gradually disappearing.
Not at all; it just needs to reduce the average number of children the average person has. Any mutation that makes it "less troublesome" on average would be favoured.
http://www.wolframalpha.com/input/?i=pancreas+cancer http://www.wolframalpha.com/input/?i=appendicitis
That's correct, but, from my understanding, revolutionary mutations are orders of magnitude less likely to happen than evolutionary mutations.
Everyone has an appendix, so there's no natural selection pressure where non-appendix people are breeding to further the spread of non-appendix humans. Just thinking out loud here - I reckon the way it would have to go would be if the appendix was a significant disadvantage, and people with a less sensitive/smaller/less prominent/something-like-that appendix were able to survive more easily or have more children on average, then you might selection pressures moving towards a less prominent and eventually no appendix.
It could happen, but it'd take a long time. Actually, one that fascinates me is what effect modern medicine and technology will have on evolution. Greater mobility is seeing children with a more mixed and diverse hereditary mix. Beyond that though, longer life cycles and better medical treatment might mean both slower and less evolution. I'd expect a lot of positive effects from interbreeding of different peoples over the next 500 years, but I reckon, sadly, that things like aggression won't be genetically bred out of us any time soon by being selected for less. Interesting stuff to think about.
[Edit: I took you to mean that pigment was generally not beneficial, but probably you meant only in certain environments, which would be fair enough.]
Most of the population is now vitamin D deficient because people don't spend much time outside.
It may not be simple quantity of exposure, but rather severe sunburns that most elevate risk. If one is outside regularly and acclimatized, these severe burns are less likely to occur.
Perhaps someone else will have a more detailed comment on this.
Of course, one's pigmentation will also influence the likelihood of sunburn, although dark pigmentation does not entirely prevent burning.
EDIT: Just read InclinedPlane's comment, above, which mentions the same concern with sunburn.
"Melanin helps protect the skin against effects of the sun such as skin cancers and premature aging. In African American skin, melanin provides a sun protection factor (SPF) approximately equivalent to 13.4, compared to 3.4 in white skin. This discrepancy illustrates why skin cancer is more prevalent in Caucasian people"
http://www.skincancer.org/skin-cancer-and-skin-of-color.html
Inexplicably it also correlates with a higher tolerance for electrical pain, which might be a useful adaptation for hackers :)
In response to that, your thymus (?) which is influenced by light levels now diminished because you covered your eyes with dark glass, releases less melanin which makes your skin more susceptible to UV light. It's weird, your skin is more likely to burn because you are wearing sunglasses.
I believe it was CBC Radio quirks and Quarks where I heard it.
Also, (I mentioned over at Reddit) another interesting thing is the ability of the majority (95%) of adult northern Europeans to be able to digest milk. the next closest group are people from India where 50% of adults are able to digest milk.
Please deliver my Nobel prize in the mail, thanks.