homeostasis: temp, regulation Flashcards
ectotherm
have a body temperature that is determined by the environment
endotherm
able to generate enough heat to elevate their own temperature to a high stable level
benefit of endotherms
allows the nervous system to function at a steady high level so animals can remain active in the winter and exploit habitats denied to ectotherms
what are some behavioral adaptations that exist in ectotherms
-thermoregulation in lizards: hour to hour changes in solar radiation to keep body temp constant
-thermoregulation in bees: on warmer days they spread water on comb or fan air inside with wings. on colder days, vibrate wing muscles to stay warm.
endotherm adaptations for hot environments
-small desert animals are fossorial and nocturnal.
–burrows have lower temps and high humidity reduces water loss from evaporation.
–some have morphological adaptations increase SA
-large desert ungulates:
–have glossy light-colored fur that reflects sunlight and acts as insulation. heat is lost at the underside through convection and conduction.
–fat tissue on back insulates and impairs heat transer
endotherm adaptations for cold environments
-have thick fur and underlayer, and visible guard hair for protection
some birds: down feather to conserve heat
-extremities protection
what protects extremities?
countercurrent heat exchange: prevents body from losing heat
-arterial blood passes through small veins and contacts cold blood. heat exchange system> back to body.
what is adaptive hypothermia
abandon homeothermy for extended periods of time and let body temp fall.
why does adaptive hypothermia exist?
endothermy is genetically expensive and must always have an energy supply
what are the types of adaptive hyperthmia
-daily tropor
-true hibernation
-prolonged sleep
-summer sleep
drops body temp, when asleep or inactive to prevent energy loss. ex. humming bird
daily tropor
entry is gradual and includes a series of test drops in body temp, animal eventually cools and metabolism decreases, respiration and heart rate drops. cannot be awakened.
true hibernation
prolonged sleep
body temp does not drop. only heart rate drops. can be awakened if disturbed
summer sleep
breathing rates and metabolism decrease when temp is high or animal is dehydrated
surface area
determines heat loss, amount of space in body heat can come out
