PNB 2250 Lecture Notes - Lecture 14: Brown Adipose Tissue, Thermal Mass, Aestivation
5 Oct 2016
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Considerations: heat is constantly produced by metabolism. Enzymes and cells are very sensitive to heat. Some animals can produce more heat than others because of varying metabolisms: animals differ in whether their core temperature varies with the environment and whether they can internally generate enough heat. Why is body temperature so critical: all biochemical processes are temperature dependent, at a10 degrees celsius increase all enzyme activity will increase by. Consequences: heterotherms operate at peak efficiency only at an optimal temperature. They can tolerate a wider range of temperature extremes: homeotherms operate at peak efficiency at a wider range of temperatures. This ability requires a greater sophistication and expenditure of energy. Lethal temperature: temperature at which at least 50% of animals will die, not an absolute value- adaptable. Evolutionary advantage: affected by prior exposure. Temperature tolerances: some animals tolerate a very small range of temperature, others can tolerate a great temperature range.
