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Exploring Biological Anthropology: The Essentials, 3 rd Edition. CRAIG STANFORD JOHN S. ALLEN SUSAN C. ANTÓN. Chapter 6 Human Variation: Evolution, Adaptation, and Adaptability. Human Variation at the Individual and Group Levels. What is a Population?. Deme. Subspecies. Race.
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Exploring Biological Anthropology: The Essentials, 3rd Edition CRAIG STANFORD JOHN S. ALLEN SUSAN C. ANTÓN
Chapter 6Human Variation: Evolution, Adaptation, and Adaptability
Human Variation at the Individual and Group Levels What is a Population? Deme Subspecies Race Polytypic Species
Historical Perspectives on Human Variation • Recording Human Variation in Past Civilizations • Ancient Egyptians: recognized physical differences of people around them • Ancient Greeks: recognized “Ethiopians” who were dark-skinned people • Romans: had at least as extensive knowledge as the Greeks of the variety of peoples that could be found in the western part of Eurasia and north Africa; limited contact with Han Chinese traders
Historical Perspectives on Human Variation (cont’d) • The Monogenism-Polygenism Debate • Monogenism: all people of all races are the product of a single creation • Environmentalism: the view that the environment has great powers to directly shape the anatomy of individual organisms • Polygenism: the different races can be viewed in terms of their own evolutionary history
Historical Perspectives on Human Variation (cont’d) Race and Racism in the Twentieth Century Racism: A prejudicial belief that members of one ethnic group are superior in some way to those of another.
Historical Perspectives on Human Variation (cont’d) Changing Attitudes Towards Race Focus on ‘populations’ Ethnic Groups
Historical Perspectives on Human Variation (cont’d) • Deconstructing Racial Features • Skin Color • Eye Form • Hair Color and Form • Head Shape
Population Genetics • Population genetics: the study of genetic variation within and between groups of organisms • Microevolution: the study of evolutionary phenomena that occur within a species
Population Genetics (cont’d) • Polymorphisms: ABO and Other Blood Type Systems • Polymorphic: two or more distinct phenotypes that exist within a population • Maternal-Fetal Incompatibility • The Human Leukocyte Antigen (HLA) System
Population Genetics (cont’d) Gene Flow and Protein Polymorphisms Migration ABO System
Population Genetics (cont’d) Gene Flow in Contemporary Populations Örség of Hungary African American Studies
Population Genetics (cont’d) • Polymorphisms and Phylogenetic Studies • Phylogeny: an evolutionary tree indicating relatedness and divergence of taxonomic groups • Branch • Node • Cavalli-Sforza: a genetic tree of the world’s populations
Polymorphisms and Natural Selection in Human Populations • The Evolution of Lactose Tolerance • The Genetics of Lactose Tolerance • Lactose/lactase • Lactose malabsorbers • LCT*P • Explanations for the Lactase Polymorphism • Cultural historical hypothesis • Lactose tolerance is an example of the interaction of biological and cultural factors
Polymorphisms and Natural Selection in Human Populations (cont’d) • Balanced Polymorphisms: Sickle cell and Other Conditions • Sickle cell • Heterozygous Advantage • Balanced Polymorphism • Other Possible Disease-Associated Balance Polymorphisms • Tay-Sachs disease and cystic fibrosis
Adaptation and Adaptability • Adaptability: the ability of an organism to make positive changes after exposure to stressful environmental conditions
Adaptation and Adaptability (cont’d) • Levels of Adaptability • Acclimatization: the process of short-term changes in physiology that occur in response to changes in environmental conditions
Adaptation and Adaptability (cont’d) • Heat and Cold • Vasodilation • Vasoconstriction • Body Size and Shape • Bergmann’s Rule • Allen’s Rule
Adaptation and Adaptability (cont’d) • Living at High Altitude • Hypoxia or “oxygen starvation” • Increasing heart and breathing rates • Increase in hemoglobin concentrations • Skin Color • Melanin • Latitude and clinal variation • Vitamin D and the Vitamin D line