Why do people of african origin have broad, flat noses?

Question

I am not a racist, I believe in equality and that we're all human beings. I've just always wondered why people of African origin have flat noses compared to those of some asians and caucasians.

Answer 1

I would agree with eternal, except how does the nose rule work for the Inuit?

Answer 2

I would dispute Brenna's claim that the descendants of Africans in the  new world displayed different features due to any form of natural selection - those few generations are probably not enough to effect any change. The likelier cause is the introduction of Caucasian genes into their gene pool.

Otherwise, yes - different peoples adapted to their respective climates.

Answer 3

Eternal is correct. It's called Thompson's Nose Rule, and it states that the more nasal area, the more effectively air can be warmed up and therefore not do as much damage to the lungs as cold air would.

Similarly, because of  Allen's Rule, you'll notice that a lot of African populations are long and lean as compared to those of Northern decent, like Alaskans and Native Americans who are short and thick.

More surface area due to length vs. stoutness allows greater dissipation of heat. The thinner and longer of two bodies will lose heat quicker than thicker and shorter, which conserves heat wonderfully.

Answer 4

The reason that people from cold climates have long noses, is because the air gets a chance to "warm up", before entering the lungs!

People who originated from near to the Equator, didn't need to develop this special adaptation!

Answer 5

Don't quote me, but I believe I've heard it's because they come from really hot areas, and it makes it easier to breathe and stay cooler.

Answer 6

Yep, it's the climate that does it.  If you look at people around the world from very similar climates they tend to have similar features.  

Another point that solidifies the climate argument is that there was a  study done recently on the African Diaspora, which is the transport of Africans to America during the slave trade.  The features of these people at first are obviously African, but then a look at their descendents one, two and three generations down the line and you can see that there is quite a bit of change in the features which means that they're caused by the climate the people live in.