BIOLOGY 4X03 Lecture Notes - Lecture 15: Hypocapnia, Circulatory System, Anaerobic Respiration
8 Nov 2016
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High altitude: low temperature, low oxygen, maintaining thermogenesis, sustaining heavy cost of flight (locomotion) Exaptations: things that are gong to allow birds to evade high altitudes; evolutionary adaptations: larger hearts, more capillaries in their hearts, modified cardiovascular system, more effective gas exchange, unique respiratory system. Extract oxygen twice from ambient air: metabolic rearrangement to overcome things that humans cannot, hypocapnia. Bar headed goose: migrates over everest, fly at night; compounds the cold issue; gets colder as elevation increases. More efficient at extracting oxygen: larger lungs, larger air sacs, more surface area for gas exchange, can extract o2 more efficiently. Hemoglobin becomes more stable, increasing affinity for o2: modified muscle physiology. Shift mitochondria near the outside of the cell: have a recovery time. Waterfowl model: have independent lineages, birds at high altitude are geographically isolated from their low altitude counterparts, not diverged (low altitude) more diverged diverged (high latitude) Complex 4 oxygen binds to the mitochondria.
