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Outline Of Darwin's Theory Of Natural Selection

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After the Beagle returned to England in October 1836, Darwin began reflecting on his observations and experiences, and over the next two years developed the basic outline of his groundbreaking theory of evolution through natural selection. But beyond sharing his ideas with a close circle of scientist friends, Darwin told no one of his views on the origin and development of life. Indeed, he did not publish his now-famous volume, On the Origin of Species by Means of Natural Selection, until 1859, more than 20 years after he had first formulated his theory. On the Origin of Species may never have been written, let alone published, if it had not been for Alfred Russel Wallace, another British naturalist who independently proposed a strikingly similar …show more content…

Which do you think has the greatest effect on human variation? (20 marks. Length: 300-400 words).
The three primary causes of human variation are:
(1) Evolutionary processes, which affect genetic diversity within and between populations;
(2) Environment The variation among individuals that springs from their unique life experiences in specific environments; and
(3) Culture- the variation stemming from disparate cultural beliefs and practices inculcated during an individual’s formative years and reinforced throughout life.
Evolutionary processes, which affect genetic diversity within and between populations has the greatest effect on human variations A population’s total compliment of genes of referred to as a gene pool. In Homo sapiens, as well as in many animal populations, genes may have two or more alternate forms – a phenomenon called polymorphism. These differences are expressed in various physical characteristics, ranging from hair and eye colour to less visible difference in blood chemistry. Many of these traits vary in their expression in different world areas. For examples, we associate certain hair texture and skin colour with populations that can distinguished regionally on the basis of discrete physical traits are called …show more content…

Mutations may result in evolutionary change only of they occur in the sex cells of individuals. Mutations are important in explaining human variation because they are ultimately the source of all genetic variation.

The evolutionary process that determines which new mutations will enter a population is natural selection. Through this evolutionary process, traits that diminish reproductive success will be eliminated, whereas traits enhancing the ability to reproduce will become more widespread. Throughout human populations gene flow is seen as a result for some physical characteristics. The genetic drift is particularly useful in explaining differences among genetically isolated populations, and also the processes of selection that alter allele

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Mutations deals with the production of DNA cells based on a natural selection by chance. Genetic Drift is solely based on changes and has nothing to do with natural selection. Non-Random mating deals with that populations that chooses their mates based of their

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According to Recent and Ongoing Selection in the Human Genome published in the National Center for Biotechnology Information, the human genome appears to be targeted by selection. The researchers estimate that at least 38% of all new amino-acid altering mutations in the human genome are being eliminated by negative selection. As Homo sapiens outlived Homo neanderthalensis, it is a plausible conclusion that genetically humans are more adapted to Earth’s

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Rowan McCarthy Kim ½ Period 6 Race: A Ruinous Colonial Construct For hundreds of years, humans have been separated into groups based on cosmetic, and supposedly genetic differences, called race. However, although there might be some cosmetic variation between races, there are no real genetic differences. Since humans originated in Africa, every gene originated there, and race is a concentrated version of those traits based on settlers in that area, although many genes did get passed around the world through trade.

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Race and ethnicity are two terms which are used interchangeably in every day conversation, however, there is a distinction between the two. Race is a categorization of people who have been singled out as inferior or superior, often on the basis of phenotype – observable physical characteristics such as skin color, hair texture, eye shape, or other selective attributes. Race is a social construct and has been known to change with historical and political events. Contrarily, ethnicity does not necessarily provide visual clues, instead, ethnicity is categorized on the basis of a shared common culture and includes elements such as language, norms, customs, religion, music, art, literature. Ethnic Groups are developed by their unique history

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The socially constructed idea of race to which you subscribe—a biological myth—exists strictly to dehumanize select populations of people. Genetic markers denotating race cease to exist. Genetically, humans are among the most similar of all species. Over this past summer, you might recall my work in the biology department with fruit flies. Between any two fruit flies, you would find ten times greater difference between them than there exists a difference between yourself and the brown-skinned man at the grocery counter.

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Overall, the human variation of skin color in both discussions is based primarily on geography, climate, and natural selection, which embody the cline

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Differences ranging from the “color, hair, shape of skull, proportions of the body, etc.” (Darwin 213), are too small to even have affected the role of natural selection, however, if they were or were not important, then over the years, these differences would have, “fixed and preserved or eliminated” (Darwin 217) due to natural selection. Nevertheless, there is no prominent variation, even among people who live in different climates. Therefore, these differences are negligible compared to the similarities. Moreover, Darwin believes, “none of the differences between the races of man are of any direct or special service to him” (Darwin 217).

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This means that if genes were to affect the differences in all of these traits, they could also react to changes in natural selection. So we humans could still be evolving, because of all the genetic differences in the population, putting aside medicine and all advancements. Also, like the Rambam Maimonides Medical Journal says, “...human cultural evolution did not stop human populations from adapting to infectious diseases but rather most likely intensified human adaptive evolution to infectious

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Human variation is the genetic difference both within and among populations. There are three main causes of human variation namely mutation, gene flow and sex. These causes combined make it very unlikely for any two humans to have the exact same genetic make ,even twins who develop from the same zygote have slightly deferent genetics due to mutation, gene flow and sex. Mutation effect DNA changes, gene flow is a cause of genetic variation from one population to another and sex is a source of gene combinations which all lead to a vast variation in human

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