Thermoregulation

What are the four mechanisms of heat transfer

Conduction, radiation, convection, and evaporation

Conduction

Heat gained or lost by direct contact

Radiation

Heat gained from solar radiation or lost to cooler environments from the body via infrared radiation

Convection

Heat lost via a moving fluid

Evaporation

Heat lost from energy turning water from a liquid to a gas (no way to gain heat through this)

Factors effecting heat transfer in animals

Size/surface area, and amount of conductance

Size/Surface area

Smaller animals have a higher surface area to mass ratio which means they will gain and loose heat faster

Amount of conductance

Influenced by the amount of insulation an animal has, the more insulation the less heat is lost

The greater the difference in temperature between the environment and the body the.....

Greater the heat loss or gain

Endothermic (warm-blooded)

Body heat produced by metabolism, occurs in most mammals and birds, maintains a constant body temperature not dependent on the environment. May take advantage of behavioural mechanisms (huddling) and some increase insulation in cold seasons, both use less energy than increasing metabolism

Heterothermic

Can be endothermic or ectothermic depending on conditions, occurs in bats, bees, moths, and hummingbirds, can undergo rapid and drastic changes in body temperature.

Ectothermic (cold-blooded)

Body heat gained from the environment through behavioural mechanisms, occurs in most fish, reptiles, amphibians, and invertebrates, body temperature is variable but still regulated

Vasoconstriction of peripheral blood vessels helps\______ heat loss, and vasodilation \______ it

reduce, increases

Shivering uses \________ to heat the body

muscles contractions

Sweating is \_______ which releases heat through the skin

evaporation

Animals that can't sweat do what instead?

Pant

Heterorthermic

Creatures can be endo or ectothermic based on conditions, species often practice nightly torpor. Ex. Hummingbirds, bats, bees, and moths