MODERN HUMAN VARIATION Flashcards
explain how variation was categorised
- Linnaeus (1700s) and Blumenbach (1800s) classified human populations based on physical characteristics e.g. skin color
- Early anthropologists used observable traits (e.g., skin color, ABO blood system, height, BMI) to categorize people into “races.”
what was the conflict when categorising humans by race
Races in humans are meaningful biological groups - real differences in important characteristics between races
VS
Races in humans are social constructions - disconnected from biology
what did David Reich claim
- argued that biological data (e.g. ability to breath at different altitudes, milk digestion) could be used to sort humans into racial groups or subspecies - these vary independently - some anthropologists avoid examining this due to the sensitivity of the topic -
- also suggested races may differ in behavioral or cognitive traits - a statement that has sparked debate
what is a subspecies
- geographically isolated population
- Semi-independant evolutionary trajectories
what can we use to detect subspecies / genetic differentiation between populations
Fst tests - >0.25 = different species / subspecies
example of how Fst is used to distinguish species
0.43 - result of western vs eastern chimps
0.46 = result of western vs central chimps
0.05 = result of southeastern vs eastern chimps
0.03 = result of southeastern vs central chimps
- So would say come in 3 different sub species – lots of sex within but not between subspecies
- Humans = 0.04 - between humans – not coherent enough to justify categorizing humans into subspecies
Examples of how humans differ
- Starch digestion: Some populations have higher levels of salivary amylase (important for starch digestion)
- Disease risk: Certain populations have higher risks for specific diseases (e.g., African Americans and sickle cell disease) - more about disease prevalence in ancestry, not about race as a biological category
