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Why do most people have black hair?

Alexmahone

Active member
Jan 26, 2012
268
What kind of evolutionary advantage does black hair confer? I would have expected most people (young as well as old) to have white hair because it reflects heat and therefore keeps heads cool.
 

dwsmith

Well-known member
Feb 1, 2012
1,673
What kind of evolutionary advantage does black hair confer? I would have expected most people (young as well as old) to have white hair because it reflects heat and therefore keeps heads cool.
Maybe it is like having light eyes. Having light eyes is a mutation from dark. Maybe all the people with hair that isn't black or brown natural had a mutation in their genes.
 

Alexmahone

Active member
Jan 26, 2012
268
Maybe it is like having light eyes. Having light eyes is a mutation from dark. Maybe all the people with hair that isn't black or brown natural had a mutation in their genes.
But why should black hair be normal in the first place?
 

dwsmith

Well-known member
Feb 1, 2012
1,673
But why should black hair be normal in the first place?
Read why blue eyes are mutations and you may accept why it is more common. It has to do with the production of melanin being turned down. If it is turned down in the hair, we have light hair. But the being turned down isn't normal.
 

Prove It

Well-known member
MHB Math Helper
Jan 26, 2012
1,404
Isn't it because dark hair genes are dominant, while lighter hair genes are recessive?
 

Alexmahone

Active member
Jan 26, 2012
268
Isn't it because dark hair genes are dominant, while lighter hair genes are recessive?
But why are dark hair genes dominant? (Sorry if this is an ignorant question.)
 

Prove It

Well-known member
MHB Math Helper
Jan 26, 2012
1,404

CaptainBlack

Well-known member
Jan 26, 2012
890
What kind of evolutionary advantage does black hair confer? I would have expected most people (young as well as old) to have white hair because it reflects heat and therefore keeps heads cool.
You could ask the same question about skin colour, it is probably due to how the pigments involved deal with UV.

(note dark at optical wavelengths tells you little or nothing about reflectivity at UV or IR)

CB
 

Moo

New member
Feb 12, 2012
26
But why are dark hair genes dominant? (Sorry if this is an ignorant question.)
It's like if you ask why when you mix white with black, you obtain something nearer to black than white (in equal quantities).

By the way, there isn't only one gene determining eye or hair color.
 

Alexmahone

Active member
Jan 26, 2012
268
It's like if you ask why when you mix white with black, you obtain something nearer to black than white (in equal quantities).
If we mix equal quantities of black and white, don't we obtain something equidistant from black and white?
 

CaptainBlack

Well-known member
Jan 26, 2012
890
If we mix equal quantities of black and white, don't we obtain something equidistant from black and white?
Reflectivity does not quite work like that, for one thing it depends on how the pigmants do their thing. If on a monitor you define the colour mixing to be linear then of course it will be (but that is not reflectivity, except on e-paper where again you can define a 50-50 mix to 50% of black pixels and 50% of the dirty white that passes for white).

CB
 
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anky2930

New member
Apr 13, 2012
2
In my opinion its natural and its best answer is available to god himself.
 

CaptainBlack

Well-known member
Jan 26, 2012
890
In my opinion its natural and its best answer is available to god himself.
That is not an answer at all. If you go down the root of "some god did it" (or "some god knows") you still have the question why?

There is either an adaptive reason (some advantage to one colour over another) or it is a random consequence of a process (like the victory of VHS over Betamax).

CB
 

Amer

Active member
Mar 1, 2012
275
because if the most people have blonde hair you will ask why most people have the blonde hair
that was just a joke.
the black hair gene generates a protein that gives a color
and the blonde hair gene dose not produce less color
something like that

you can ask why do most people have black eyes
I heard that black hairs are stronger than other colors thats true although for the black eyes
 

Wilmer

In Memoriam
Mar 19, 2012
376
All's not lost: google "black and white whiskey"