Ch 10 Flashcards
(24 cards)
key points of thermal relations (2)
- diverse between animal and enviro
- temperature plays a major role in lives of animals / determines where each species can live
examples of global warming
increasing temps
1. temp affects where eastern phoebes overwinter
- changes distribution of fish species (cod&blenny / shifted more towards poles)
- limit cardinalfish ability to engage in aerobic exercise
- less caterpillar abundance affects how great tits can feed their young when they hatch in spring
4 mechanisms by which an animal exchanges heat with enviro
- conduction (ground)
- convection (air)
- evaporation (respiratory)
- thermal radiation
thermal relations are categorized by (2)
endothermy & thermoregulation
describe thermoregulation
how well can maintain a relatively constant tissue temperature
example of endotherms vs poikilotherms(ectotherms)
endotherms - mammals & birds
poikilotherms - fish
describe endotherms vs poikilotherms
endotherms - generate heat internally to maintain a constant body temperature
poikilotherms - body temps vary with enviro
what is a thermoregulating poikilotherms also called
behavioural thermoregulators
what are thermoregulating endotherms also called
homeotherms
temporal vs spatial variation with example
temporal
= an animal has different thermal relations to its enviro at different times
ex. hibernating
spatial
= animal has different thermal relations in different parts of its body
ex. arctic mammals
poikilotherms can have responses in 3 major time frames
- acute (steeper on a graph)
- chronic (flatter on a graph)
- evolutionary (specialization)
what is special about hibernating animals
ectotherms when hibernating and then homeotherms the rest of the year when not in hibernation
describe homeothermy (4)
- produce own heat
- can maintain usual body temp under different enviro conditions
- not absolutely constant due to DAILY cycle but remains stable
- high energy cost & food requirements
what is TNZ and what happens outside of this zone
TNZ = thermoneutral zone
- animals resting metabolic rate is independent of ambient temperature
outside of this zone ~ metabolic rate increases
how do mammals and birds thermoregulate (2)
- insulation
- shivering / non shivering thermogenesis
describe insulation (4)
- fluffed out plumage increases resistance of heat transfer
- alter rate of blood flow
- postural changes (curling up)
- body size (small have more heat loss, larger better at insulation)
shivering vs non shivering
shivering
- use ATP
- releases heat
- no useful mechanical work
non shivering
- via brown adipose tissue
- best known in placental mammals
describe brown adipose tissue (4)
- different origin from white fat
- rich supply of blood vessels and mitochondria
- generates heat via oxidative phosphorylation
- is vascularized
is white adipose tissue vascularized ?
no
oxidative phosphorylation vs uncoupling
O.P = ATP synthase for synthesis of ATP
uncoupling = UCP1 cell, generates heat instead of ATP
regional heterothermy
allow some tissue to cool in cold enviro’s (ones closer to enviro)
- arctic mammals
describe countercurrent heat exchange & what must happen for it to be affective
= permits selective restriction of heat flow to appendages
(blood vessels must be close to eachother so heat can be passed between)
examples of chronic responses to seasonal changes (3)
- acclimatizarion of peak metabolic rates
deer mice ~ same insulation in winter and summer (small mammals and birds) - acclimatization of metabolic endurance
- insulatory acclimatization
red fox ~ greater insulation in winter than summer (mid size/ larger species)
controlled hypothermia
reduce difference between body and enviro temp
- loses heat more slowly and has lower costs
