BIO120H1 Lecture Notes - Lecture 15: Ecophysiology, Thermoregulation, Homeostasis
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BIO120H1 Full Course Notes
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Modes of heat gain and loss: homeostasis. Size, shape, insulation, evaporative cooling, behavioral thermoregulation. Biodiversity: more than just the # of species, also diversity of morphologies/physiologies/behaviors. Physiology reflects climate and other conditions to which organism is adapted. Similar environments often lead to similar adaptations (convergent evolution) E. g. temperature animals withstand cold temperatures better than tropical animals. And wider range of temperatures because temp variation low near equator and increases with latitude. Heat balance especially important to homeotherms (birds & mammals) Poikilotherms (reptiles, amphibians, fish, invertebrates) lack physiological means to deviate from environmental temperature (use behavioral means), temperatures fluctuate. Homeotherms must regulate heat balance to keep internal temperature within a narrow range, many traits contribute. Because maintaining a constant internal temp requires energy, poikilotherms have lower energy requirements than similarly sized homeotherms. Conduction: transfer by direct contact with substrate. Redistribution: circulatory system redistributes heat among body parts. Homeostasis: surface area to volume ratio (large is quick, small is slow)
