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Unformatted text preview: 2-25-09Part IILecture 21. The Concept of Stress2. Adaptive Domains3. Skin Color as an AdaptationAdaptations arise in response to STRESSStress: some concepts-Homeostasis- the optimal internal environment of the body: temperature, water balance, blood pressure, pH, nutrient balance. etc-Stress- disturbance in, or departure from, homeostasis-Stressor- anything that causes stressExamples:oStressor: temperature is over 100 degreesoStress: You go outside to mow the lawn which increases in internal body temperature, causing deviation from normaloAdjustment: Activation of sweat glandsHeat is moved from body core to skin surface, via sweatEvaporative cooling: drop in internal body temperatureAdaptive pressures (stressors) in human microevolution-Climate and geography:oTemperature and aridityoUV radiationoAltitude-Adaptations to the above ^oBody shape and size, basal metabolic rateoSkin coloroCardiovascular, metabolic, pulmonary functions-Other adaptive pressures:oDisease -> RBC, HLA polymorphisms...
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- Spring '09
- Biological Anthropology