explain the actual human biological variation and human racial classification

“The Heritability Hang-Up.” Science 190: 1163–1168. Genetic studies demonstrate that about 85.4 percent of all the variation in the human species can be attributed to variation within populations and that there is only a 6.3 percent difference between “races,” with less than half of this value accounted for by known racial groupings (see Lewontin 1972; Barbujani, Magani, Minch, et al. People adapted to cold climates have acquired genetic traits that provide them extra layers of body fat, which accounts for the epicanthic fold over their eyes. But humans also need vitamin D, which is synthesized by sunlight from sterols (chemical compounds) present in the skin. Refer to each style’s convention regarding the best way to format page numbers and retrieval dates. In another example, suppose that Australian aborigine trackers and Peruvian Andean weavers are asked to identify a series of drawings that will make a complete square as fast as possible. Therefore, be sure to refer to those guidelines when editing your bibliography or works cited list. “Apportionment of Racial Diversity: A Review.” Evolutionary Anthropology 10 (1): 34–40. Feldman, Marcus W., and Richard C. Lewontin. In a second argument against the biological reality of race, theorists claim that even if non-human subspecies exist, there are no human ones; hence there are no races (Lewontin, Rose, Kamin 1984). New York: Free Press. Brues, Alice M. 1977. In this case, the identification of the origin of people in a geographic area does have some justification as a proxy for differences in environmental and other factors of relevance for public health. In the taxonomic literature, “race” is any distinguishable type within a species. Many features are now known to relate to the environmental conditions of the populations that carry them. Racial and ethnic groups are not an inherent feature of human society, but constructed in different ways that vary according to time, place, and political interests. New York: Columbia University Press. As shown in Figure 2, the normal range for IQ for about 67 percent of the population falls between 85 to 115, while only 5 percent of the population attain IQ values greater than 140 and below 70. To understand why, we must keep in mind that racial labels are distinct, discrete categories while human physical and biological variations (such as skin color, hair color and texture, eye color, height, nose shape, and distribution of blood types) are continuous rather than discrete. . For example, the large-scale migrations between Africa and Europe, as well as the colonial expansion of European populations into Asia and the New World, have resulted in the mating of individuals from different continents and the concomitant mixture of genetic traits. The ancient Greeks, on the other hand, referred to all Africans as “Ethiopians.” A major tenet of the biological concept of race is that the traits that identify a given race are unchangeable and have been fixed since the beginning of humankind. These findings together indicate that the lower IQ scores associated with black samples is more a function of educational experiences than of genetic determinants. 2004. Binet, Alfred, and Théodore Simon. The cline in skin colours shows variation by infinite degrees; any attempts to place boundaries along this cline represent purely arbitrary decisions. Short, stocky body builds with stubby fingers and toes are correlated with cold, wet climates, such as are found in Arctic areas. 2001. Scientists have known for many decades that there is little correlation between “race,” used in its popular sense, and actual physical variations in the human species. In areas of the world where the indigenous population was sparse and widely scattered (such as Australia), the map's colour density can be misleading. In this activity, you will analyze data on genetic variation and address a series of questions about variation … The Development of Intelligence in Children (the Binet-Simon Scale). 1975. As these groups adapted to northern climates with limited sunlight, natural selection brought about the gradual loss of melanin in favour of skin tones that enabled some individuals to better synthesize vitamin D. Other physical characteristics indicate adaptations to cold or hot climates, to variations in elevation from sea level, to rainforests with high levels of rainfall, and to hot deserts. After all, we might argue that races are among the largest and most Anthropologists consider the meaning of the inclusive of such human groups, and many people word “race” in two different ways. It is expressed as h2 = G/P = G/(G + E), where G is variability in genotype, E is variability in environment, and P is variability in phenotype. So why do these racial labels not accurately describe human physical and biological variation? As a result of these processes, genetic diversity follows a pattern characterized by gradients of allele frequencies that extend over the entire world. Indeed, his conclusions that biological human races (or subspecies, for these purposes) do exist, and conform generally to ancestral continental regions, appear remarkably m… Brown, Ryan A., and George J. Armelagos. Between populations with light skin and those with the darkest coloration are populations with various shades of light tan to brown. The “correct” answer, therefore, depends on the children’s past experience. In the United States, for example, the people identified as African Americans do not share a common set of physical characteristics. Boas demonstrated that the cephalic index (the ratio of head width to head length) of children born to immigrants to the United Stateschanged because they grew up in a different environment than that of their parents. Haldane, John B. S. 1949. Compared to “race,” those factors not only better describe human variation, they invoke evolutionary processes to explain variation. Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox. For this reason, professionals with a genetics education have a broad range of career opport…, Genetic counseling is the process in which a specially trained professional communicates with a person, couple, or family about the occurrence, or ch…, Nature-Nurture Controversy 1976. In addition to the MLA, Chicago, and APA styles, your school, university, publication, or institution may have its own requirements for citations. Variability is partly heritable and partly acquired. “An Apportionment of Human DNA Diversity.” Proceeding of The National Academy of Sciences USA 94: 4516–4519. This does not mean that a person’s genetic makeup is not a significant factor in individual intelligence in particular areas. Available from http://www.physanth.org/positions/race.html. On a map of this scale, it is difficult to give more than a representation of current understanding. However, this difference is more a reflection of the different educational experiences of black and white Americans. Furthermore, data and models from DNA studies suggest that common race definitions pertaining to humans have little taxonomic validity, because there is no correlation. Because each style has its own formatting nuances that evolve over time and not all information is available for every reference entry or article, Encyclopedia.com cannot guarantee each citation it generates. This genetic unity means, for instance, that any local group contains, on average, 85 percent of the genetic variation that exists in the entire human species. Initially, three classes were identified by anthropologists: Caucasoids, Mongoloids, and Negroids; later, Australoids and Capoids (Bushmen) were added. New York: Columbia University Press. Grab a copy of our NEW encyclopedia for Kids! Mutable and fluid, the history of racial categories reflects not melanin or nationality, but power. In other words, heritability of intelligence (unlike genetic determination) can be very different in different populations, depending upon the environmental condition in which each population develops. Similarly, lactose tolerance occurs both in European and African populations, not because they have the same racial origin, but because both were evolutionarily adapted to dairy products. Lewontin, Richard C. 1972. IQ AND RACE: MISUSE OF SCIENTIFIC INFORMATION, THE USE OF GEOGRAPHIC AREA AND RACE IN BIOMEDICAL RESEARCH. Before the onset of European exploration in the late 15th century, it was believed that humans were descended from a single pair and should not be placed into different categories as other animals were. Yet in the United States, tests of IQ have been used to measure general intelligence. They point out that the distribution of IQ scores in black Americans is shifted to the left, so that there are higher frequencies of low IQ scores and lower frequencies of high IQ scores when compared to white Americans. According to these authors, “geographical races” refer to an aggregate of phenotypically similar populations of a species inhabiting a geographic subdivision. Some adaptive variations are not obviously visible or measurable. Based on this result, one might conclude that the Guatemalan rural children do not know how to add or subtract. 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