BIO 203 Lecture Notes - Lecture 3: Brown Adipose Tissue, Countercurrent Exchange, Aestivation
16 Nov 2016
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Document Summary
Mechanisms in endotherms to compensate for heat loss to the environment. In low tamb, there is a large driving force for heat loss and body temperature unless: There is an in mr ( in endogenous heat production) Behavioral changes to increase heat gain or decrease heat loss. Ex: move into the sun or put on a sweater. Endotherms require ~17 times more energy than an ectotherm of the same size/mass. More suited to variations in food supply. Can exploit a broader range of body sizes/shapes. Since tb = tamb , freedom from heat conserving restriction. Can function with much smaller body masses. Ingested food/energy available for producing biomass rather than maintaining high tb. Place goldfish in water with a temperature gradient and observe behavior. Behavioral thermoregulation - selecting temperature by behavior. Heliotherm - heat source is the sun. Thigmotherm - heat source is the substrate (earth, rocks) Gained (in) through conduction, convection, and radiation.
