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
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What does influence skin color variation is the size and distribution pattern of melanosomes as well as other factors.
A major function of melanin is to act as a defensive barrier of the skin against radiation damage. Ultraviolet light between the wavelengths 280-320nm (UV-B) causes sunburn and damages the skin on nonpigmented peoples. Exposure to this degree of light causes their skin to become dry, leathery, and wrinkled in appearance similar to that associated with aging. This can be seen in Whites living in Australia and South Africa, where ultraviolet light intensity is high because of the relative latitude or closeness to the equator.
Melanin is also said to be linked with hearing. Melanocytes are present in the inner ear, the eye, and in the membrane that covers the brain and spinal cord. It has been demonstrated that melanin deposits in these areas are proportional to the amount of melanin found in the skin . These areas of the body, similar to the skin, are exposed to high-energy free radicals that can damage the surrounding cells, and thus causing a lower threshold for hearing.
Evidence shows that black people, on average, hear better than whites, and that within both races, women surpass men. A partial explanation of the differences may lie in the abundance in the inner ear of melanin pigments. Also, numerous studies have found that people with light eye colors, such as blue, green, and hazel, are more
Many people think that is it possible to achieve a “healthy tan,” but this thought has been proven wrong. Overexpose to UV-A and UV-B rays from the sun lead to premature aging of the skin, as well as the possible formation of skin cancer, know as melanoma. An appearance of a tan is actually a stage of burning and damage to the skin. Although a tan may be desirable to many, the fact remains that more people need to be educated on the dangers of the sun’s harmful rays, and the possible health complications of overexposure.
Geographical isolation in the past has caused a variation in skin color; natural selection selected specific skin pigments depending on environmental factors. Early humans who moved to Europe were introduced to a place that had less sunlight than their former place of residence. Overtime, light skin (skin with lower levels of melanin) was selected for since there were not as many UV rays that the skin needed protection from. But, what was wrong with having dark skin in Europe? How is extra melanin a disadvantage in this case? One thing to remember is that even though the sun can provide UV rays, sunlight is also a great source of natural vitamin D (Jablonski; Kirchweger). Vitamin D helps bones absorb calcium and is particularly essential for developing embryos in pregnant women. The adaptation for lighter skin was important because the skin needed to absorb as much sunlight as it could in order to receive optimal amounts of vitamin D (Kirchweger). However, too much vitamin D can be fatal. So as high amounts of melanin protected the skin from excessive UV rays in Africa, they also protected it from excessive vitamin D (Kirchweger).
In the article Skin Deep written by Nina Jablonski and George Chaplin, they discuss and look deeper into the diverse differences in skin color. Our skin color has developed over the years to be dark enough to prevent the damaging sunlight that has been harming our skin and the nutrient folate that it carries. At the same time out skin is light enough to receive vitamin D.
Caucasians have the lowest amount of melanin in their skin cells when being compared to other cultures. Melanin is crucial to protecting our skin from UV rays, and so someone with a darker skin tone is better protected.
It develops in the melanocytes, which are cells that produce melanin that gives the skin its pigment or color and protects tissues from ultra violet radiation. Dark skinned people have more melanin than light skinned people do. For this reason, Melanomia is more frequent in light skinned people. (“Detailed description “, 2000, P.2
5. In the film, Dr. Jablonski explains that melanin, located in the top layer of human skin, absorbs UV radiation, protecting cells from the damaging effects of UV. Genetics determines the type of melanin (i.e., brown/black eumelanin or red/brown pheomelanin) and the amount of melanin present in an individual’s cells. Based on this information, write a hypothesis for where in the world you would expect to find human populations with
Melanocytes are pigment-producing cells commonly found in your lower part of your outer layer of skin, which is known as the epidermis. The natural color of your skin is produced by melanin. When skin is being exposed to
In a film of “Race the Power of an Illusion, Part I The Difference Between Us”, it talked about the differences of races such as skin, eye, hair color. However, in our genetic, the human is not very different than we think but we had a similar genetic code. In the 1950s, the athlete champions were all black, and they were much better than any other. Maybe because of that some people think there are different structure bodies than other races. In this case, I think it could make sense that black people have better body structure than white. However, it is the wrong stereotype about skin color. The skin tone is continuously changing, and the reason why a human has different physical appearances is that of different genes we have. Depends on the
The meaning, significance, and definition of race have been debated for centuries. Historical race concepts have varied across time and cultures, creating scientific, social, and political controversy. Of course, today’s definition varies from the scientific racism of the eighteenth and nineteenth centuries that justified slavery and later, Jim Crow laws in the early twentieth. It is also different from the genetic inferiority argument that was present at the wake of the civil rights movement. However, despite the constantly shifting concepts, there seems to be one constant that has provided a foundation for ideas towards race: race is a matter of visually observable attributes such as skin color, facial features, and other self-evident
As the research continues it becomes ever more important to discuss how exactly the differing pigmentation of one race of people actually occurs, because I feel that it has an effect on the way colorism is handled throughout the African American community. There are two ways in which a person of African descent can be of a lighter complexion; the first being amalgamation, which is the coming together of both the black and white races and reproducing to make a mulatto or mixed race child and the second is the use of cosmetic creams in attempt to bleach one’s skin until they too appear mulatto (Dorman 48). This is relevant because, it shows the extremes that people are willing to go to reach the highest plateau of social acceptance. Many of these creams were painful acidic chemicals slowly burning away the pigmentation as people slept, while others were considered mild abrasive materials used to “gently” scrape away dark pigments (Dorman
An example of an area would be in the European areas, where the UV radiation doesn’t beam down as strong onto our skin. If it was another hot open area such as Australia then the skin pigmentation stayed darker. In short, the skin pigmentation adapted to the lifestyle and the surround environment to better help survive in that climate. This is due to the body producing more melanin so the effects of the sun’s rays can be counteracted. Through generations successful genes are passed through the blood line, the human body also has a tendency to produce a particular amount of melanin depending on the location of where one
Could the color of your skin really affect who you will evolve to be? Maybe not as much now but definitely over 100 years ago before the modern period occurred. The world has transmuted so much from segregation to integration and diversity is now seen more as auspicious. The beginning of this transformation unlocked new opportunities for black cultures and their arts, music and writings as the Harlem Renaissance emerged. However, the expedition to acquire this great change was filled with tribulation. Glancing back, it is perspicuous that the years 1914-1945 made a vast alteration in our nation’s outlook from the skills and talents of the valiant African-Americans; along with the authors that wrote to divulge their struggles such as Langston Hughes, Zora Hurston and Countee Cullen.
Race is not a biological reality because there are no indications of some biological DNA that would have a certain outcomes of a race. The variation in skin tone comes from the mix of certain races. For example, the mix of black and white would result a skin color of Latino. However, the mix of white and yellow (Asians) will most likely result a child having more essential characteristics of white people. It is impossible to classify humans into races because human is making a new race every single moment from the combination of two people who come from different races. Light skin and dark skin have a lot to deal with the temperature, latitude and langtitude of the region. It could be characterized by a regions, instead of ethnic groups. Race
Although very informative, I nearly lost interest in the subject as it was a bit dry, however, with the incorporation of pictures, I was able to grasp the science of how this structure functions and the significance of melanin, “the most important substance imparting color to skin” (9). Melanin is formed in cells called melanocytes, located between the dermis and epidermis; these cells produce different amounts of melanin and this is the main reason why people have different skin colors (11,14). The author breaks down the scientific terms in a clear and coherent
For a long time, the term “albinism” referred only to people who had white hair, white skin, and blue eyes. Individuals who had OCA and pigmented hair and eyes were identified, particularly in the African and