Hair color why the difference?

In summary, hair color in humans is determined by specific chemicals such as eumelanin, pheomelanin, and melanin. These chemicals also play a role in skin tone and tanning. The absence of proteins that emit green light and the need for UV protection and Vitamin D synthesis contribute to the limited range of hair colors in humans. Further research is needed to fully understand the complexities of hair color and its relationship with visible light.
  • #1
HungryChemist
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Can someone explain to me why there are difference in humans hair color? Why black and blond and brown and red only? Why not green?
 
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  • #2
The colours are a result of particular chenicals such as eumelanin (black and brown), pheomelanin(red) and melanin (less melanin = darker hair). Melanin is also responsible for dark skin tones and for tanning.

There are no proteins in human hair that emit green light, and very few humans with chlorophyll in their hair.

Actually, you'll find out all you need to know on Wiki: http://en.wikipedia.org/wiki/Hair_color
 
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  • #3
This is really a good question.

At present the best explanation has to do with the hair's role as a photoprotective element. That is, it blocks too much UV from irradiating the scalp. Why don't all people have black hair then, after all that would be the "safest" thing from the point of view of UV protection?

Turns out some UV is needed for Vitamin D synthesis. Thus some UV must get through, if too much is blocked probability of survival goes down. The lighter hair colors allow more UV through, the darker colors less. So, evolution "selected" darker hair in areas of high UV intensity and visa versa.

This doesn't explain all the subtleties of hair color though, i.e. the variations seen in the absorption spectrum across the visible band. There is more to the story but all the facts aren't in yet in that regard. This, to me, suggests there remains something to be learned about the photophysiology of visible light on humans.
 

1. Why do people have different hair colors?

People have different hair colors because of the amount and type of pigment called melanin in their hair follicles. The more melanin, the darker the hair color will be.

2. Can hair color change over time?

Yes, hair color can change over time due to a variety of factors such as hormonal changes, aging, and exposure to chemicals or environmental factors.

3. Is hair color determined by genetics?

Yes, hair color is determined by genetics. The genes you inherit from your parents determine the amount and type of melanin in your hair follicles, which ultimately determines your hair color.

4. Why do some people have natural highlights or lowlights in their hair?

Natural highlights or lowlights occur when the amount of melanin in certain areas of the hair follicles is different from the rest, resulting in a variation of hair color. This can also be influenced by exposure to sunlight.

5. Can hair color be artificially changed?

Yes, hair color can be artificially changed through the use of hair dyes or bleaching agents. These products chemically alter the amount and type of melanin in the hair follicles to achieve a desired hair color.

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