lecture 17 - surviving extreme temps Flashcards
part 3
torpor
physiological state of decreased actviity + metabolism
torpor enables animals to
save enegry while avoiding difficult and dangerosu conditions
hibernation
long term torpor that is an adaptation to winter cold + foo scarcity (in endotherms)
how much lower can metabolic rates be during hibernation than if the animal attempted to maintain normal body temp
20x lower
the molecuar components of the biological clock stops what during hibernation
stops osciliating
brumation
long term torpor exhbited by ecotherms
what shows start of hibernation
drop in temp
metabolic rates can drop __% when animals are in torpor
90
during arousal state of torpor waht is activated/used
BAT
-uncoupling proteins to warm blood and warm animal
what do animals do when they are awake from torpor
when they are awake they eat, pee, poop and sometimes drink
-foods will be digested
-ready to return to torpor
is bear hibernation same as small animals
no
do we really know what type of hibernation bears have?
no, debate of if it is torpor or if they are super hibernators
why do bears have much less heat loss
becaus ethey have a smaller surface area to body mass ratio
bears hiberation is
long sleep period w/ lowered metabolic rate and lower body temp
how much will bears body temp drop by
4-7C
do bears sleep as deep as small animals
no, they can wuickly be aroused
-females wake to give birth and check on cubs
do bears eat, drink, pee, poop during their hibernation period
no
-recycles waste moleqs for productive use by the body
bears hibernation cycle is
active, hyperphagia (eat a lot), then hibernation (insulin reisstant)
daily torpor
some endotherms exhbit daily torpor, they are small with high BMRs
daily torpor is often adapted to
feeding schedule
hummingbirds exhbit _____
nightly torpor
estivation can go on for how long
days or weeks
estivation is
summer torpor
what is the problem estivation is trying to help with
dehydration
estivation enables animals to
survive long oeriods of high temo wth scarce water
how do animals perform estivation
find cool burrow underground (anything that is well insulated)
in estivation there is less
evaporative cooling
what is relaxed during estivation
relax control of body temp
do animals breathe more or less during estivation
less, so less respiratory water loss (H2O lost breathing out)
is mechanism in supression of metabolic rate during torpor known
no
fucntion of metabolic rate supressed during torpor
drop in MR is not a fucntion of lowered body temo since drop in MR precedes drop in body temp
current research of metabolic rate supression during torpor is focused on
mtochondria
