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Explore the historical views of human variation, the concept of race, and contemporary interpretations of human variation. Discover the role of genetics and population dynamics in shaping human evolution and the impact of environmental factors on human health.
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Chapter 14 Modern Human Biology: Patterns of Variation
Chapter Outline • Historical Views of Human Variation • The Concept of Race • Racism • Intelligence
Chapter Outline • Contemporary Interpretations of Human Variation • Population Genetics • Evolution in Action: Modern Human Populations • Human Biocultural Evolution
Historical Views of Human Variation • Two schools of thought developed to explain diversity: • Monogenists believed that all humans were descended from a original pair of humans. • Polygenists believed that all humans were descended from a number of pairs of humans.
Historical Views of Human Variation • Biological determinism - cultural and biological variations are inherited in the same way. • Eugenics - "race improvement" through forced sterilization of members of some groups and encouraged reproduction among others.
Traditional Concept of Race • Since the 1600s, race has been used to refer to culturally defined groups. • Race is used as a biological term, but has enormous social significance. • "Racial traits" are not the only phenotypic expressions that contribute to social identity: sex and age are also critically important. • In the 1950's the use of the term "race" was replaced with "ethnicity "
Allele FrequenciesWithin and Between Populations • After World War II, the study of human variation shifted to the study of differences in allele frequencies within and between populations. • The application of evolutionary principles to human variation has replaced the view that was based solely on observed phenotype. • Races are no longer viewed as fixed biological entities, composed of individuals fitting a particular type.
Groupings Used by Lewontin in Population Genetics Study (1972)
Environmental Factors • Global warming may expand the range of tropical diseases. • The spread of disease is associated with encountering people; this includes crossing borders and penetrating remote areas. • The increasingly large human population leads to overcrowding, unsanitary conditions and the spread of communicable disease.