BIO120H1 Lecture Notes - Lecture 15: Wind Chill, Heat Transfer, Homeostasis
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BIO120H1 Full Course Notes
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The hotter you are the more heat you lose by radiation. Transfer by direct contact with substrate (e. g. , feet lose heat to the ground) Heat transfer mediated by moving fluid (e. g. , wind chill, usually air or water) Water has a high heat of evaporation. Sucks heat out of an organism to turn liquid water into gas. Circulatory system redistributes heat among body parts, esp. core to appendages. Size matters to heat balance (and other balances of gains and losses) Large volume have more heat, both volume and surface area increase as they get bigger but at different rates. Heat balance especially important to homeotherms (birds, mammals) Poikilotherms (most reptiles, amphibians, fish, inverts) lack physiological means to deviate from environmental temperature (although they use behavioral means): their temps fluctuate. Homeotherms (mostly mammals and birds) must regulate heat balance to keep internal temperature within a narrow range: many traits contribute to regulation.
