1. Modern Human Biology: Patterns of Variation
Chapter 14
Modern Human Biology: Patterns of Variation

2. Chapter Outline Historical Views of Human Variation
The Concept of Race
Racism
Intelligence

3. Chapter Outline Contemporary Interpretations of Human Variation
Population Genetics
Evolution in Action: Modern Human Populations
Human Biocultural Evolution

4. 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.

5. 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.

6. 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 "

7. Allele Frequencies Within 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.

8. Groupings Used by Lewontin in Population Genetics Study (1972)
Geographical Group
Examples of Populations Included
Caucasians
Arabs, Armenians, Tristan da Cunhans
Black Africans
Bantu, San, U.S. blacks
Asians
Ainu, Chinese, Turks
South Asians
Andamanese, Tamils
Amerinds
Aleuts, Navaho, Yanomama
Oceanians
Easter Islanders, Micronesians
Australians
All treated as a single group

9. Distribution of B allele in Indigenous Populations

10. Genetic Polymorphisms Used to Study Human Variation

11. Population Genetics Research

12. 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.