Presentation on theme: "Physical and Cultural Adaptation to High Altitude Environmental Stressors: Cold Stress-Cultural and Physical Aridity-Cultural High Solar Radiation-Cultural."— Presentation transcript:
Physical and Cultural Adaptation to High Altitude Environmental Stressors: Cold Stress-Cultural and Physical Aridity-Cultural High Solar Radiation-Cultural Hypoxic Conditions-Physical Adaptation versus Adjustments Acclimatization
Behavioral Ecology: Evolutionary Perspective Genetic or Evolutionary Adaptation- Change in Gene frequencies and takes a long time Phenotype/Developmental Adjustments-Behavior and Morphology Individual or Population response to Environment Why would Genetic Adaptation be negative? Isolated Populations: Genetic Drift Gene Flow- Migration and Globalization Mutation
Hypoxic Conditions : Lower Barometric Pressure results in less oxygen available: same amount in air, but is less dense, so less oxygen is inhaled. At 4500m- Oxygen pressure decreases by 40% from sea level Culture cannot change oxygen levels in environment Human Adjustments are Physiological-Developmental to maintain Aerobic Metabolic Processes and maintain stable
How Do Humans Adjust to Hypoxic Stress? Oxygen Transport System of the Body Lungs: Capacity Heart: Blood Flow Blood: Red Blood Cells (volume) and Hemoglobin Oxygen Saturation
Lungs: Developmental Chest Cavity Increase: Volume (timing and exposure) Enlarged Nostrils Greater Residual Lung Volume: Retain Oxygen Pulmonary Ventilation: 20-40% higher- BUT doesn’t increase metabolism-nor hyperventilation Hypocapnia- low Carbon Dioxide in blood? Dilated Alveoli of Lungs Dilation of Capillary Beds in Lungs
Oxygen Saturation in the Blood: 1890: Viault counted red blood cells between high and low altitudes in Peru- 5 mill to 8 mill at 4500m. Increase Oxygen in the Blood Red Blood Cells Hemoglobin- Protein in rbc that carries Oxygen Increase in rbc thickens blood Enlarged Capillaries that transport blood: is this a response to thicker blood or an adjustment to move more blood more quickly to get more oxygen?
Chronic Mountain Sickness: Monge’s Disease Acclimatization: Those adjusted going from high to low to high Polycythemia: increase in rbc and hemoglobin causes blood to thicken This will cause heart failure and lung failure Cures: Move to low altitude immediately Phlebotomy-Bleeding Progesterone helps: increase respiratory ventilation This is most common in Males High Altitude Pulmonary Edema (HAPE) High Altitude Cerebral Edema (HACE)
Reproduction Cultural versus Physiological Fecundity: Change of Conception-Exposure to intercourse/marriage, Sperm Production, Menarche, Lactational Infecundability Fertility: Production of live offspring. Infant mortality rates. Low Birth Weights/Fetal Growth Retardation: Is this an adaptive advantage? Is this an adaptive repercussion (mother)? Is this the cause of high infant mortality in the first month? Does cold stress influence this? Living conditions, nutrition?
Growth Developmental Stages of life Chest cavity will enlarge at this stage of life High Alt. adolescence/puberty usually not complete till mid-20s. Shorter growth effects males more- less sexual dimorphism Does diet and nutrition effect native high altitude growth? High Alt. native children need more energy: work, cold, hypoxia Less protein and developmental nutrients? Is being smaller an adaptive response to the cold?
Are these Biological Adjustments Universal? NO!! Andes: “Classic”-Increase hemoglobin, lung volume and oxygen saturation. Tibet: Same hemoglobin as lower altitudes, increase resting ventilation though, and oxygen saturation. Ethiopia: Have neither of these…how do they remain in this hypoxic environment?? How does this reflect longevity of being at high alt and microevolutionary processes? Do they enhance Darwinian Fitness? Costs and Benefits???
Coca Use in the Andes: Physical and Cultural Meaning Hypoglycemia Control: Blood Sugar Atropine-An amino alcohol Heat Retainer/Vasoconstriction Appetite Suppressant Seasonal Energy Stress and Caloric Deprivation Vitamins and Mineral Supplements: Vitamin A; llipta- calcium
Cold Stress Temps. Will drop.5 C for every 100m Some evidence that Andean people can resist harm to extremities. Smaller extremities, larger core. Can withstand lower core temperatures than Europeans. Small stature-low surface mass ratio, can retain heat better What about children and LBW? Most cold stress adaptations are cultural regulatory responses: Clothing Shelter Schedule