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
Throughout history race has been a pivotal part in decision making. Since the first interaction of populations from different geographical regions, with physical differences, the assumption has been that these differences were fundamental. These physical differences, based mainly on the color of skin, have been classified as race. Over time physicians have tried to pinpoint certain characteristics that are more prominent in one race than another, in order to prove race and that there are subspecies of humans. One of the first examples of this is Johann Blumenbach work “On the Natural Variety of Mankind”. In his work Blumenbach introduced five categories of race; caucasian. mongolian, malayan ethiopian, and american. These classifications revolved around not only skin color, but also physical morphology. Blumenbach supported this by using a collection of physical evidence, like the structure of the cranium, to support his thesis. This marked a shift in thinking of race in terms of geography to physical appearance. Published in 1775, Blumenbach’s dissertation started the scientific approach to finding
Anthropologists and geographers have studied and overtime come to the conclusion that distribution of skin color is not random. Darker skin color has been found to typically come from near the equator and lighter skin colors are typically coming from closer to the north and south poles. Over the years, researchers have found that darker skin colors has protected the skin from having skin cancer. Recent studies have shown that “skin color is the product of natural selection acting to regulate the effects of the sun’s ultraviolet radiation on key nutrients crucial to the reproductive success” (169).
Hannibal’s campaign against Saguntum, who was an ally of Rome at the time was became a prelude for the beginning of the Second Punic War. Although this conflict was believed to have been instigated by the Romans who instilled hostility towards Carthage in Saguntum’s government. Hannibal marched on the city, lay siege to it and later claimed it after its fall 8 months later. Outraged the Romans declared war on Carthage and thus the Second Punic War ensued. He then
Rodriguez, Richard. “Complexion”. Good Reasons. eds, Lester Faigley, Jack Selzer. Boston: Longman Publishers, 2001. 441-443.
In today’s culture, being tan coincides with what is believed to be beautiful. As a result, it is no surprise that in the United States of America, an estimated 922,000 people are currently living with some level of melanoma. Even though the news media and doctors warn people about the risks of too much sun exposure and give information as to how to prevent contracting skin cancer, people are still disregarding this important information and going into the sun for extended periods of time unprotected.
There are two common misconceptions about melanoma. The first is that melanomas develop only in sun-exposed areas of the body. In fact, melanomas can occur in areas not normally exposed to the sun, including the abdomen, genitals, and soles of the feet. The second misconception is that dark-skinned and Asian people are not at risk for the disease. In fact, one type of melanoma occurs most frequently in African American and Asian populations, developing on the palms, soles, and nail beds.
This meant that over time, humans lost most of their hair on their bodies, leaving their skin exposed. Sweat glands were going to help the body cool down, but they couldn’t protect the skin from harmful UV rays. This is where melanin works its magic, and it’s the reason for the diversity in skin color today. Melanin helps reduce the absorption of wavelengths into the skin (Chaplin, Jablonski, 59).... ...
In the past, races were identified by the imposition of discrete boundaries upon continuous and often discordant biological variation. The concept of race is therefore a historical construct and not one that provides either valid classification or an explanatory process. Popular everyday awareness of race is transmitted from generation to generation through cultural learning. Attributing race to an individual or a population amounts to applying a social and cultural label that lacks scientific consensus and supporting data. While anthropologists continue to study how and why humans vary biologically, it is apparent that human populations differ from one another much less than do populations in other species because we use our cultural, rather than our physical differences to aid us in adapting to various environments.
Albinism happens when one of numerous genes is fault. Each of these genes offers orders for making one of several proteins involved in the making of melanin. This imperfection may outcome in the nonappearance of melanin production or a cheap quantity. Melanin is produced by cells called melanocytes, which are found in your skin and eyes. The amount of coloring varies. Some people gain a little pigmentation in their hair or eyes when aging. Some develop pigmented spots on their skin. A person with total absence of melanin is called an albino. One with only a small amount of melanin is described as albinoid. (What is Albinism by Right Diagnosis April 22, 2014).
The Second Punic War, also called the Second Carthaginian War, took place from 218 to 201 B.C between the Roman Republic and Carthaginian Empire. There were three Punic Wars in all, resulting in Roman dominance over the Mediterranean. Rome saw how large Carthage was getting and how much power it was gaining. This, along with the fact that Carthage controlled three islands off the coast of Italy, was an issue for Rome. Rome insisted that Carthage join the Republic, to which Carthage disagreed. The two groups fought for twenty years, ending the wars when Carthage offered Rome the island of Sicily in exchange for peace. Rome took Sicily, Corsica, and Sardinia. Carthage, lead by Hamilcar Barca, took off to fight Spain. Hamilcar’s son, Hannibal, was nine years old at the time. Before they left Carthage, Hamilcar made his son promise that when he was older he would fight Rome for revenge. Hannibal agreed, thus beginning the legend of Hannibal, military genius. (Second)
In the darkest hour of the Roman Republic, an army was led against all odds to reign supreme on the Italian peninsula. Led through sheer military genius, the Carthaginian Army laid waste to everything the might of Rome could muster. For years on end, Italy was the stage for the greatest military orchestra the world had yet seen, conducted by a master of strategy and warfare. Hannibal, son of Hamilcar Barca, laid siege to the very idea of Rome’s military prowess. Despite absolute dominance of the Italian peninsula for several years, his success can not be credited to his brilliance and mastery of strategy. Hannibal’s success can be primarily attributed to Rome’s failure to respond at key points of his advance into Italy.
The first Punic War was started when soldiers from the city of Syracuse decided to get involved in a dispute on the island of Sicily which was then controlled by Carthage. Syracuse attacked the city of Messina, before the attack the two cities had no problem with each other and they supported each other. Rome built its fle...
Firstly, in order to compresence the complexity of our debate, we have to take in mind the definition of nature and nurture. Yes, is true that some of our characteristics are inherited by our ancestors, most of our physical characteristics, such as hair color and type; the pigmentation of our skin, those are a product of our genes thus our DNA (Jewel, 2007).
The color of your skin used to depend on where you live. (Before transportation became so easy.) Darker skinned people would live where it is hotter, and the sun shines more. Lighter skinned people would live in cooler, less sunny areas. This is because the darker pigments in your skin would keep you from burning.
Albinism is a very serious disease that could end up in death. Albinism is a recessive inherited defect in melanin, which is metabolism in which pigment is absent from skin, hair, and eyes. Albinism in hair, skin, and eyes is called oculocutaneous albinism. Humans that have oculocotaneous albinism are not able to produce melanin. These people have white, yellow, or yellow brown hair, very light ( usually blue ) eyes, and very pale skin. Their eyes may appear pink because they have very little pigment.