Why do different races have different physical features?

Question

Some examples: Why do Asians and Native Americans have almond-shaped or slanted eyes and straight black hair? Why do Africans have very curly hair and full lips and broad noses? Why do Caucasians vary so much in their coloring? Why do Hispanics have high cheekbones?

I realize not everyone fits these descriptions, but why do these differences exist?

I know it has to do with their environments, but I mean specifically?

Answer 1

Color variations exist so much with whites possibly because it's so much easier to change the color of something that's light-colored than something that's dark.  I don't know that that's all there is to it though.

The proximate cause of different races having different physical characteristics, of course, is that certain genes exist only rarely in certain population groups: blue eyes (recessive) are concentrated in Europeans, for instance.

Light vs. dark skin is easy, of course: melanin protects the deeper layers of skin from sun damage, so populations in sunny areas tend to have darker skin.  Eye color may be similar, but that's just speculation on my part.  Shapes of facial features etc., though, I don't know.  I've wondered myself, but haven't heard much about it.

Answer 2

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Answer 3

Well it does have a lot to do with the environment but it's primarily related to evolution. Native Americans are said to have originated from areas such as Siberia while passing the bridge which is why they share a lot of similar features to Asians.

Hopefully this won't come off as being racist (even though I'm Asian myself), but there was a theory that Asians have slanted eyes to avoid getting dust and debris there (of course, this varies with geography, but especially where I'm from (southern China) people have slanted eyes and eyelashes that point downwards (our eyelashes don't curl up unlike most other races.) The list goes on, and since I doubt you want to read an essay about evolutionary traits, haha, i'll just leave that as one example. Hope this helps.

And contrary to what the first guy said, I think your topic is fascinating.  

Answer 4

The answer in general is evolution, natural selection. Well in reality there is only the human race because humankind is one single species. But the variety comes from the fact that long ago our ancestors were isolated geographically. The Native Americans, the Anglo-Saxons and what not were divided by oceans and mountains. You can imagine that they interbreed within their own population and over time physical traits become more homogenous or uniformed. The environment played a big part in making a certain trait more expressed than another. If a certain person can survive better because their skin or hair allows them better chance of sneaking of up on prey animals, then they will get better chance to procreate. Over time natural selection will choose people with genes more fitted to the environment. In the later eras, slanted eyes might be a popular trait to the society living in the Asia continent. But different traits are brought about by a slight mutation in our genes. If a new trait shows up and it proves beneficial for those who have it, then they will become popular.