Yeah I'm pretty sure pigmentation as protection against varying levels of UV is how it goes. I don't know what to make of the interesting example Chuck brought up with the Native Americans though!

Quote:Skin color is just an adaptation to the amount of direct sunlight a given people have over time. Darker skin is more resistant to sunlight so it protects from sunburn, useful in tropical climates. Lighter skin sucks up sunlight, useful if its in short supply.

But....as logical as that sounds, people who live in the Congo Basin rain forest, where sunlight has trouble penetrating the tree canopy,



are just as dark as people living in Sudan where there is plenty of sunlight.



Perhaps they commute?

(September 21, 2012 at 1:04 am)Minimalist Wrote:

Quote:Skin color is just an adaptation to the amount of direct sunlight a given people have over time. Darker skin is more resistant to sunlight so it protects from sunburn, useful in tropical climates. Lighter skin sucks up sunlight, useful if its in short supply.

But....as logical as that sounds, people who live in the Congo Basin rain forest, where sunlight has trouble penetrating the tree canopy,

Even in the rain-forest there are areas such as clearings where the sunlight has little to no difficulty penetrating to the ground.

I think naive adaptationist explanations run quickly awry when you have multiple evolutionary mechanisms, operating at different levels, and different mechanisms of population dispersal.

Though I would like to know how Jesus managed to have such a large stable of fine, fine whores without being black.

(September 21, 2012 at 12:51 am)DeistPaladin Wrote:

(September 21, 2012 at 12:08 am)FallentoReason Wrote: How do you explain the skin pigmentation of people living thousands of kilometres from fish such as countries in the middle of Africa? Or are their diets still vitamin D rich anyways?

I always thought skin colour was a direct adaptation to how strong the sun was in that region..?

That's my understanding as well. This theory is born out by the pattern we see where the closer you get to the equator, the darker the skin, while the closer you get to the poles, the lighter the skin.

We can see this effect not just in Europeans but other people in the world. Compare among Native American tribes the Eskimo of Alaska to the Inca of Peru. Compare in East Asia the Mongolians to the Siamese. Among Europeans, compare the Italians to the Scandinavians.

Skin color is just an adaptation to the amount of direct sunlight a given people have over time. Darker skin is more resistant to sunlight so it protects from sunburn, useful in tropical climates. Lighter skin sucks up sunlight, useful if its in short supply.

You can just as easily come up with counterexamples. For example Northern Chinese tends to be significantly darker than southern Chinese.

Well, we are kind of dull colours. Imagine the fuss about, if there were purple, green and blue ones

(September 21, 2012 at 9:36 am)Chuck Wrote: You can just as easily come up with counterexamples. For example Northern Chinese tends to be significantly darker than southern Chinese.

There are some anomalies with this theory but overall there is a recognizable pattern coupled with the fact that we do know how different skin tones react to sunlight exposure. It all falls into place nicely. The anomalies will probably be explained as we get more information.

Tangent:
This discussion reminds me of how evolution is often accused of promoting racism by creationist propaganda. However, I find that naturalistic explanations like the ones we're batting about demystify our differences and reveal just what minor distinctions they are (we've tragically built up these artificial distinctions based on how much or little sunlight your immediate ancestors got).

Compare this with what religion often offers. See the Mormon explanation for races or the curse on Ham or the "Mark of Cain". I'd say religion does far more to promote racism and ethnic cleansing than a rational, scientific approach to understanding our world.

Quote:Even in the rain-forest there are areas such as clearings where the sunlight has little to no difficulty penetrating to the ground.

And what? They all hang out in the clearings to work on their tans?

(September 21, 2012 at 10:59 am)LastPoet Wrote: Well, we are kind of dull colours. Imagine the fuss about, if there were purple, green and blue ones

There are.

You bleached people either make us crazy (purple), sick (green), or dead (blue).

(September 21, 2012 at 11:20 am)Minimalist Wrote:

Quote:Even in the rain-forest there are areas such as clearings where the sunlight has little to no difficulty penetrating to the ground.

And what? They all hang out in the clearings to work on their tans?

As a matter of fact, the villages where they live and spend much of their time socializing would most likely be located in a clearing. They may not deliberately be trying to catch any rays but they will under such conditions.