Why do most people have black hair?

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In summary, black hair is said to confer an evolutionary advantage because it reflects heat and keeps heads cool.
  • #1
alexmahone
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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.
 
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  • #2
Alexmahone said:
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.
 
  • #3
dwsmith said:
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?
 
  • #4
Alexmahone said:
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.
 
  • #5
Isn't it because dark hair genes are dominant, while lighter hair genes are recessive?
 
  • #6
Prove It said:
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.)
 
  • #7
Alexmahone said:
But why are dark hair genes dominant? (Sorry if this is an ignorant question.)

That's not an ignorant question at all. I suggest you read http://www.thetech.org/genetics/ask.php?id=227.
 
  • #8
Alexmahone said:
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
 
  • #9
Alexmahone said:
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.
 
  • #10
Moo said:
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?
 
  • #11
Alexmahone said:
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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  • #12
In my opinion its natural and its best answer is available to god himself.
 
  • #13
anky2930 said:
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
 
  • #14
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 that's true although for the black eyes
 
  • #15
All's not lost: google "black and white whiskey"
 

1. Why is black hair the most common hair color?

The most common hair color is determined by genetics. The gene for black hair is dominant, meaning it is more likely to be passed down from parents to their offspring. This is why most people have black hair.

2. Is black hair a result of a particular race or ethnicity?

No, black hair can be found in people of various races and ethnicities. It is a common misconception that black hair is only found in people of African descent. In reality, people of Asian, Native American, and Pacific Islander descent can also have naturally black hair.

3. What causes hair to have different shades of black?

The amount and type of pigment, called melanin, present in the hair shaft determines the shade of black hair. People with more eumelanin, a dark brown pigment, will have darker black hair. On the other hand, people with less eumelanin and more pheomelanin, a red pigment, will have lighter black hair.

4. Can black hair turn a different color?

Yes, black hair can turn a different color due to genetics, aging, and environmental factors. Some people may experience graying of their black hair as they age, as the production of melanin decreases. Exposure to sunlight, chemicals, and certain hair products can also cause black hair to fade or change color.

5. Are there any advantages or disadvantages to having black hair?

There are no significant advantages or disadvantages to having black hair. It is simply a physical characteristic determined by genetics. However, people with black hair may experience different cultural perceptions and stereotypes based on their hair color. They may also have unique hair care needs, as black hair tends to be more coarse and requires extra moisture and maintenance.

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