Presentation on theme: "Modern Human Diversity: Race and Racism"— Presentation transcript:
1Modern Human Diversity: Race and Racism Chapter 12Modern Human Diversity: Race and Racism
2Chapter Preview What Is the History of Human Classification? Is the Biological Concept of Race Useful for Studying Physical Variation in the Human Species?Is studying differences in Intelligence Among Populations Valid?What are the cause of Physical Variability?
4The History of Human Classification European scholars of the 18th through early 20th centuries classified humans into a series of subspecies based on geography and features such as skin color, body size, head shape, and hair texture.Some scholars went a step further and placed these types into a hierarchical framework in which the “white” race was considered superior to other races = racism.
5The History of The “Race” Concept “Race” refers to subspecies, and no subspecies exist within modern Homo sapiens.In the past, phenotypic differences - skin color, body size, head shape, and hair texture – were used to identify different “races”Anthropologists have worked to expose the fallacy of race as a biological concept while recognizing the existence of race as a social construct.
6Biased ResearchThe work of 19th-century Philadelphia physician Samuel Morton is an example of biased research conducted to justify prejudices.He measured a series of skulls to demonstrate the supposed biological superiority of groups of people through features of skull shape and size.
7Is the Biological Concept of Race Useful for Studying Physical Variation in the Human Species?
8The “Race” Concept in Biology In biology, a population of a species that differs in the frequency of the variants of some gene or genes from other populations of the same species.
9Factors in the Biological Definition of Race It is arbitrary; there is no agreement on how many differences it takes to make a race.Any one race does not have exclusive possession of any particular variant of any gene or genes.Populations are genetically “open,” meaning that genes flow between them and no fixed racial groups exist.The differences among individuals and within a population are generally greater than the differences among populations.
10Dermatoglyphics: Fingerprint Patterns Fingerprint patterns of loops, whorls, and arches are genetically determined. Grouping people on this basis would place most Europeans, sub-Saharan Africans, and East Asians together as “loops,” Australian aborigines and the people of Mongolia together as “whorls,” and central Europeans and the Bushmen of southern Africa together as “arches.”
11“Racial” VariationYao Ming, center for the Houston Rockets, receives his Special Olympics Global Ambassador jersey from athlete Xu Chuang (left) and Special Olympics East Asia President Dicken Yung.Standing side-by-side, these three individuals illustrate the wide range of variation seen within a single so-called racial category.
12The Concept Of Human Races While the biological race concept is not applicable to human variation, race exists as a cultural category.The confusion of social with biological factors is frequently combined with prejudices that then serve to exclude whole categories of people from certain roles or positions in society.Anthropologists have abandoned the race concept as being of no particular utility in understanding human biological variation.
13Persecution and Racial Identity Conflict in Darfur between the Janjaweed, a militia group recruited from local Arab tribes, and the non-Arab peoples of the region is a major humanitarian crisis.The number of internally displaced persons in Darfur was estimated to be 1.65 million, with an additional 200,000 refugees from Darfur fleeing to Chad.
14RacismA doctrine of racial superiority by which one group asserts its superiority over another.Racist individuals react on the basis of social stereotypes instead of scientific facts.Behavioral characteristics attributed to race can be explained with culture rather than biology.
15Is studying differences in Intelligence Among Populations Valid?
16Race and IntelligenceA question often asked by those unfamiliar with the fallacy of biological race in humans is whether some “races” are inherently more intelligent than others.But, what do we mean by the term intelligence?
17What is Intelligence?Most psychologists consider intelligence to be the product of the interaction of different sorts of cognitive abilities: verbal, mathematical-logical, spatial, linguistic, musical, bodily kinesthetic, social, and personal.Each may be thought of as a particular kind of intelligence, unrelated to the others.
18Intelligence and IQsome psychologists insist that intelligence is a single quantifiable thing measured by IQ testsIQ tests measure performance (something that one does) rather than genetic disposition (something that the individual was born with). Performance on the test reflects past experiences and present motivational state, as well as innate ability
19Intelligence and IQThe tests do not measure intelligence per se, but the ability, conditioned by culture, of certain individuals to respond appropriately to certain questions conceived by Americans of European descent for comparable middle-class “whites.”
20The Bell Curve Controversy Herrnstein and Murray argued that the difference in IQ scores between Americans of African, Asian, and European descent is primarily determined by genetic factors and is therefore immutable.
21The Bell Curve Controversy They were criticized for:violating basic rules of statisticsutilizing studies, no matter how flawed, that appear to support their thesis while ignoring or barely mentioning those that contradict itIgnoring the fact that genes are inherited independently of one another such that the alleles associated with intelligence bear no relationship with the ones for skin pigmentation or with any other aspect of human variation such as blood type
22General Flaws in Studies of Intelligence Studies attempting to document biological differences generally involve comparisons among races—a category that for humans is biologically false.Cultures vary in terms of aspects of intelligence.Most tests used to measure intelligence are biased toward the dominant culture.Intelligence cannot be linked to evolutionary forces acting in a particular environment.
24Human Biological Diversity Physical variability is a product of genetic variation as it is expressed in a particular environment.Some physical traits are controlled by single genes, with variation present in alternate forms of the gene (alleles).Physical characteristics are controlled by multiple genes and are thus expressed continuously.Because evolutionary forces act on each physical trait independently, human biological variation can be studied only “one trait at a time.”
25Human Biological Diversity The physical characteristics of populations and individuals are a product of the interaction between genes and environments.Genes predispose people to a particular skin color, but an individual’s skin color is also influenced by cultural and environmental factors.
26Human Biological Diversity Polymorphic traits = used to describe species with alternative forms (alleles) of particular genesPolytypic traits = the expression of genetic variants in different frequencies in different populations of a species
27Human Biological Diversity For characteristics controlled by a single gene (polymorphic), different versions of that gene, known as alleles, mediate variation.Example: Blood type may appear in any of four distinct phenotypic forms (A, B, O, and AB).When polymorphisms of a species are distributed into geographically dispersed populations, biologists describe this species as polytypic (“many types”).Example: In the distribution of the polymorphism for blood type, the human species is polytypic.
28ClinesAnthropologists study biological diversity in terms of clines, or the continuous gradation over space in the form or frequency of a trait.The Clinal analysis of a continuous trait such as body shape, which is controlled by a series of genes, allows anthropologists to interpret human global variation in body build as an adaptation to climate.
29Clines and the Frequency of Type B Blood in Europe
30Epicanthic Eye FoldThe epicanthic eye fold is common among people native to East Asia.While some anthropologists have suggested that this feature might be an adaptation to cold, genetic drift could also be responsible for the frequency of this trait among people of East Asia.
31Lactose IntoleranceExample of culture acting as an agent of biological selection.The ability to digest lactose, the primary constituent of fresh milk, depends on the capacity to make the lactase enzyme.
32Lactose IntoleranceA high retention of lactase (an enzyme in the small intestine that enables humans to assimilate lactose) is found in populations with a long tradition of dairying:10- 30% of Americans of African descent and 0-30% of adult Asians are lactose tolerant.Lactose tolerance are normal for 80% of adults of northern European descent.
33Thrifty GenotypePermits efficient storage of fat to draw on in times of food shortage.In times of scarcity individuals with the thrifty genotype conserve glucose for use in brain and red blood cells.Regular access to glucose through the lactose in milk led to selection for the non-thrifty genotype as protection against adult-onset diabetes.
34Thrifty GenotypePopulations that are lactose intolerant retain the thrifty genotype.When they are introduced to Western diets, the incidence of obesity and diabetes skyrockets.
35Skin Color: A Case Study in Adaptation Skin color is subject to great variation and is attributed to several key factors:the transparency or thickness of the skina copper-colored pigment called carotenereflected color from the blood vesselsthe amount of melanin , a dark pigment, in the skin’s outer layer
36Factors in Variation of Skin Color Exposure to sunlight increases the amount of melanin, darkening the skin.Selective mating, as well as geographic location, plays a part in skin color distribution.
37Distribution of Human Skin Pigmentation before 1492
38Skin Color and Human Evolution How long did it take for light pigmentation to develop in populations living outside the tropics?We can use the settlement of Greater Australia 60,000 ya to examine this question.
39Skin Color and Human Evolution The first Australians came from tropical Southeast Asia, spreading throughout Australia eventually to what is now the island of Tasmania, with a latitude and levels of ultraviolet radiation similar to New York City, Rome, or Beijing.As aboriginal Australians originally came from the tropics, we would expect them to have had darkly pigmented skin.
40Skin Color and Human Evolution In Australia, those populations that spread south of the tropics (where, as in northern latitudes, ultraviolet radiation is less intense) underwent some reduction of pigmentation but their skin color is still far darker than that of Europeans or East Asians.
41Skin Color and Human Evolution Therefore, it seems that it takes more than 60,000 years to produce significant depigmentation.It may also be that Europeans and East Asians may have lived outside the tropics for far longer than the people of Tasmania or that settlement in latitudes even more distant from the equator were required for depigmentation to occur.