According to Darwin and his theory on evolution, organisms are presented with nature’s challenge of environmental change. Those that possess the characteristics of adapting to such challenges are successful in leaving their genes behind and ensuring that their lineage will continue. It is natural selection, where nature can perform tiny to mass sporadic experiments on its organisms, and the results can be interesting from extinction to significant changes within a species.
Human beings are no exception to biological evolution. Like other organisms around the world, humans have significantly changed overtime and have developed all sorts of diverse characteristics. One noticeable characteristic of human beings is the variation of skin color. Skin color has been used to identify, classify, and verify the variation that exists in the human population around the world. How did such a distinct variation arise and how did it play into adaptation?
I’ve often heard that “humans came from monkeys,” or something similar. It is true that humans’ ancestors were primates, who first resided in warm and sunny Africa; they had similar features to today’s apes, such as a hairy body. The purpose of the vast amount of hair was to protect the body from the sun’s ultraviolet (UV) rays and to prevent overheating, mainly by acting as a barrier for the skin underneath the hair (Jablonski, 598). Some parts of the body such as palms were not covered with hair, but with sweat glands. Sweat glands allowed the body to cool off via evaporation at the surface of the skin; sweat glands were more efficient at thermoregulation. Overtime, early humans with a high amount of sweat glands were selected for since they had the best method at the time to keep themselves cool in warm environments (Kirchweger). This meant that overtime, humans lost most of their hair on their bodies, leaving their skin exposed. Sweat glands were going to help the body to cool down, but they couldn’t protect the skin from harmful UV rays. This is where melanin worked 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). The more melanin in the skin, the greater the protection against harmful UV rays, and the amount of melanin in the skin correlates with the skin’s color (more melanin means darker skin)....
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...m all over the world, with all hues of skin colors. With interracial dating and marriages and more “mixing” of skin colors, there are multiracial children with various skin colors. Genetically, it enhances variation within the individual, but what about variation within the species? I heard a joke once that eventually in the future, everyone will be beige. Will everyone mix together to an extent that there will be little to no variation anymore, at least skin deep? It’s an interesting concept to think of. At the moment, I believe that there is enough diversity within the human species that we don’t need to worry about the lack of variation in the near future. For now, we can appreciate the diversity of skin colors that has allowed our ancestors to adapt to their environments and survive. It has allowed them to create a lineage of who we are today.
Works Cited:
1) Chaplin, G. Jablonski, N. “The Evolution of Human Skin Coloration.” Journal of Human Evolution 39 (2000) 57-106
2) Jablonski N. “The Evolution of Human Skin and Skin Color” Annual Reviews Anthropology 33 (2004) 585-623
3) Kirchweger G. “The Biology of… Skin Color” Discover 22 (2001)
This variation has no substantial ties to skin color, but does show genetic variation from different geographical locations in the world. These variations are not categorized in groups of what people call race, but rather ethnicity. Ethnicity, defined by Stephen Cornell, is a sense of common ancestry based on cultural attachments, past linguistic heritage, religious affiliations, claimed kinship, or some physical traits. Race, as most people catoragize it, encompuses many ethnicitys. Ethnicities are local populations, this makes sense that they would tend to have less genetic variation compared to each other then the rest of the world as they would share genetic adaptations resulting from the environment they live in. This can include skin color, but can also
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).
An average person can play a vital role in major historical events in several different ways. In The
Based from the film “melanin plays a role on how Africans have been able to create and developed some of the sciences that they have come to be known for”. It is also believe that melanin is a factor to soul because people with more of it moves, speaks, and acts differently than those who do not. According to a group of Africans known as the “melanin scholars” they reported a scientific base that “melanin is involved in the regulation of all psychological and physiological processes of the human body.” This makes people with more melanin stronger and smarter than those with less.² This is why, according to Welsing, whites had ambition to destroy the African race because they were inferior to their genetic superiority. In agreement to Welsing, Wade Nobles, Richard King, and other researchers/ scientists reported that whites are not entirely human since they stopped evolving with the central nervous system
Tanning is a commonly used by Caucasian women to cause their skin tone to darken. Melanin is what gives skin its color. Naturally, when we are exposed to sun, the production of a pigment known as melanin starts which itself acts as a deterrent to the burning effects of ultra violet rays of sun (Pakhare). Some Caucasians find it necessary to tan to increase beauty. It is not necessary to tan to increase beauty.
The Regional Continuity Theory, first developed in the early 1980s by Milford Wolpoff and a group of his students, asserts that after Homo erectus migrated out of Africa and moved into other portions of the Old World, local populations evolved slowly into modern humans through continuous interbreeding, genetic drift and natural selection, keeping the development of the species in the same main direction while maintaining adaptations to regional factors, but with many aspects common to all regions. The Regional Continuity Theory relies on fossil evidence far more than genetic evidence to support its claims, and cites anatomical features in Asian and European populations that carry from archaic humans to modern humans going back over 100,000 years. They, “point to the fact that many Europeans have relatively heavy brow ridges and a high angle of their noses reminiscent of Neanderthals. Similarly, it is claimed that some Chinese facial characteristics can be seen in an Asian archaic human fossil from Jinniushan dating to 200,000 years ago.”1 The merits of this theory suggest a broader expanse for evolution as a whole, suggesting that a wide array of factors, adaptations, and characteristics could feasibly create a viable species, as well as explaining so...
Leading scientists advise climate change will cause increases to the frequency and intensity of extreme weather events. Rising sea levels pose a significant risk to coastal communities, while the world’s oceans could become too acidic to support coral reefs and other calcifying marine organisms. Coral reefs contain only six per cent of the area of the Great Barrier Reef, yet they provide critical habitat and food for numerous species in the ecosystem. However, climate change has already impacted coral reefs in the Great Barrier Reef as corals are very helpless against its potential impacts. Eight mass coral bleaching events has occurred since 1979, triggered by unusually high water temperatures. And because of this, zooxanthellae (photosynthetic algae) leave their tissues and corals will have no more colours hence ‘bleaching’. Without the zooxanthellae, the corals that remain gradually starve to death. Once the coral dies, fish and a multitude of other marine species are soon affected. Rising sea levels and more frequent and intense storm surges will see more erosion of Australia’s coastline, causing community and residential
Bleaching is when the ocean water become too warm, “corals will expel the algae (zooxanthellae) living in their tissues causing the coral to turn completely white. This is called coral bleaching. When a coral bleaches, it is not dead. Corals can survive a bleaching event, but they are under more stress and are subject to mortality.” (Cave and Gillis). When a coral bleaches, it is more of like a self defense mode, which makes it turn white. The coral loses its food source as well. The downfall of this is that without the cooler waters, the corals could die of starvation or disease. Cooler waters from below can help a bleached coral bounce back to its natural state. However, if the water stays too warm for an extended period of time, “the corals don't just bleach, they cook and they die very quickly,.” (Westcott). Throughout time, much of the corals near Cairns and northward have lost the most corals. Hughes states that, “near Cairns, the Great Barrier Reef has lost 47 percent to 83 percent of their coral and as you go northward, the Great Barrier Reef has lost 11percent to 35 percent of its corals.” (Cave and Gillis). In another report, “a study last year found the largest die off of corals ever recorded with about 67 per cent of shallow water coral found dead in a survey of a 700km stretch.” (Johnston). In 2016 and 2017, there were back to back bleaching events. According to CNN reports, “back to back bleaching events in 2016 and 2017 have devastated a 1,500 km (900 miles) stretch of the UNESCO World Heritage Site.” (Westcott). Before the 2016 bleaching event of the Great Barrier Reef, there have only been two bleaching events, 1998 and 2002. According the Hughes, “only 9 percent of the reef has avoided bleaching since 1998.” (Cave and Gillis). That means that over 90 percent of the Great Barrier Reef has been affected by coral bleaching at least once in the past 19 years.
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.
The beginnings of racial difference can be traced back to the Age of Exploration, during which England was expanding its trading routes and was highly involved with trade in Africa. The English traders noticed distinguishing differences between themselves and the African people, both in physical appearance and cultural primitiveness. It was not until the 18th century when the word race began to enter languages and vocabularies, and this idea of a difference between peoples was prodded further into existence through the work of Carolus Linnaeus. Linnaeus composed a list of subspecies of human beings based on racial differences. There were several other scientists, such Georges Cuvier and Charles Darwin, as who created subspecies of man. Social Darwinism, alluded to the concept that eventually one greater subspecies of man would prevail and be the most elite of all of human kind. These lists often categorized the order of species with the white, European man at the top of the list and the darker skinned, African man at the bottom. An example of a concept of categorization was the Great Chain of Being, through which all things, including man and the subspecies of man, are given ...
The leading natural cause of destruction among the coral reefs is global warming. Global warming causes the bleaching of coral reefs to occur. Bleaching is a response to stress by the coral reef that happens when the water becomes to warm. The coral then put out a brownish zooxanthelle which causes them to lose their color. Without the zooxanthelle, the corals cannot provide nourishment for itself and th...
Evolution is the complexity of processes by which living organisms established on earth and have been expanded and modified through theorized changes in form and function. Human evolution is the biological and cultural development of the species Homo sapiens sapiens, or human beings. Humans evolved from apes because of their similarities. This can be shown in the evidence that humans had a decrease in the size of the face and teeth that evolved. Early humans are classified in ten different types of families.
The evolution of humans was (and is) a very important time. The first being of evolution was Australopithecus Afarensis or “Lucy”. Then we moved on to Homo erectus and Homo Neanderthal. When the weather got hotter, we were Homo Sapiens Sapiens and finally, the modern man. This evolution did not happen overnight. It took millions of years. The past is hardly forgotten, but the imminent is next.
Without evolution, and the constant ever changing environment, the complexity of living organisms would not be as it is. Evolution is defined as a process that results in heritable changes in a population spread over many generations (8).Scientists believe in the theory of evolution. This belief is based on scientific evidence that corroborates the theory of evolution. In Figure 1 the pictures of the skulls depict the sequence of the evolution of Homo-sapiens. As the figure shows, man has evolved from our common ancestor that is shared by homo-sapiens. The change of diet of homo-sapiens over time has thought to contribute to the change in jaw structure and overall skull shape.