Essay on Melanin

Essay on Melanin

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Melanin

Melanin has played a significant role in human evolution. In this paper I will discuss the importance of melanin in its role in the human biological system and how it relates to the natural selection of suitable human life according to geography and environment.

Human pigmentation is influenced by hemoglobins within blood vessels in the skin, carotene and melanins. Melanin, the basis of pigmentation, can be found in the forms of eumelanin and phaeomelanin. Eumelanin is the brown-black pigment located in the skin, hair, and eyes. Phaeomelanin is a yellow to reddish-brown pigment found in small quantities within the skin, eyes, and red hair. Because of these two pigments, to a greater or lesser degree, we have the variation in human pigmentation that is seen today.

Melanin is the product of cells located within the skin called melanocytes.The function of melanocytes is to manufacture the pigments eumelanin and phaeomelanin. Eumelanin, which is more photostable than phaeomelanin, is the main product of the melanocytes. In melanin, various chemicals, under the influence of enzymes, build a very stable compound that is distributed throughout the body of pigmented peoples. In an experiment by Wasterstrom, 1984, melanin exposed to up to 600 degrees C was shown to retain close to 50% of its original properties. In addition, melanin has been found in 1,000-year-old mummies and in extinct mammoth skins, according to Daniels et al., 1972.

After production, melanin is packaged in membrane bodies called melanosomes. Dark skin has large melanosomes that are in a single state and also contains more melanosomes than lighter skin such as in Europeans. Most Asian skin, on the other hand, has smaller concentrated groups of melanosomes, whereas European skin has the smallest melanosomes, which are combined into bound materials. The spacing and amount of melanosomes are what gives the appearance of skin color due to the dispersal of light hitting the skin.

A study of Melanesians found that the darker skinned inhabitants possessed large, singly dispersed melanosomes, whereas the lighter skinned inhabitants had smaller melanosomes bound in complexes . This infers that the large single state melanosome is directly related to dark skin. The size of these melanosomes are not specific to "race". For example, Africans with light skin contain the smaller ...


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...pplements and sun block creams have allowed individuals to stay healthy in many parts of the world, causing the adaptive qualities of skin and hair pigmentation to be minimized.

In conclusion, melanin production has played a considerably important role in human evolution. Not only does it influence color pigmentation through its protective role of defending against harmful UV rays, but also determines detrimental features such as eye-sight and hearing. Furthermore, melanin production and its evolutionary adaptions mark an important presence upon our biological systems to this day. Therefore, in the process of furthering human evolution, melanin production has played an enormous role in human evolution by selecting for several features that allow for particular adaptions according to the human's geographical location and environment.

Bibliography

Kitties, Rick. "Nature, Origin, and Variation of Human Pigmentation." Journal of Black Studies, Sep '95, Vol. 26 Issue 1, p36, 26p,

Hamilton, William J. Life's Color Code. McGraw-Hill Book Company. New York, 1973. Chapter 10.

Weiss, Peter. "Blue Eyes, Big Earplugs, Bad Hearing?" Scien

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