Endothermy and Hibernation

features that insulate from heat loss

feathers, hair, fat, blubber

source of heat in endotherms

metabolic activity

at rest = heart, kidneys

when active = muscles

condition when an endotherm reaches lower lethal temperature

hypothermia

condition when an endotherm reaches upper lethal temperature

hyperthermia

change in body temp and metabolic rate during hypothermia

both decrease

change in body temp and metabolic rate during hyperthermia

both increase

normothermia zone

between the lower lethal temperature and the upper lethal temperature

metabolic heat production zone

lower critical temperature through lower lethal temperature

evaporative cooling zone

upper critical temperature through upper lethal temperature

thermoneutral zone

between lower critical temperature and upper critical temperature

changes in body temp and metabolic rate in the thermoneutral zone

stays the same

do mammals or birds have a lower LCT?

birds

benefit of insulation to endotherms

lowers LCT and metabolic cost of staying warm when it gets cold

do hibernating mammals have different genes than non-hibernating mammals

no - the hibernation genes are present in all mammals, they just aren’t expressed