Behavior thermoregulation ectototherms rely on behavioral thermoregulation to adjust body temperature. Blood near the surface of the body will exchange with the environment (blood vessel dilate, vasodilation heat loss) (blood vessel restriction/constriction, vasoconstriction heat conservation. ) ***the thermoregulation lecture focuses primarily on 29. 3 and part of 32. 4**: what are the 4 mechanisms of heat transfer? (physics) The four mechanism of heat transfer is radiation, convection, conduction and evaporation. Warmer objects lose heat to cooler objects by radiation. Heat is lost by convection when a stream of air (wind) is cooler than the body surface temperature. Conduction is the direct transfer of heat when objects of different temperatures come into contact. Be able to graph body temperature vs. external temperature for each of the two. Homeotherms exhibit thermoregulation, maintaining a constant internal temperature by varing metabolic rate and insulation with external temperature. Poikilotherms are animals with body temperatures that vary with, and match, external temperature.