Torpor And Hibernation

Question 1

Hibernation in reptiles and amphibian examples

Answer 1

Tortoise species - fat reserves, metabolic inhibition, high arterial CO2, respiratory acidosis = metabolic depression

Snakes

Question 2

Hibernation example

Answer 2

Golden-mantled ground squirrel = periodic spikes in temp (80% of energy used)

Question 3

Non shivering thermogenesis

Answer 3

BAT mitochondria - cold, release of noradrenaline, lipolysis and release of coenzyme A, coenzyme A dislodge purine nucleotides from thermogenin -> mt respiration uncoupled

temp receptors, hypothalamus, thyrotropin, pituitary, thyroid stimulating hormone, thyroid, thyroxin -> cellular metabolism

Question 4

Evidence of NST in birds

Answer 4

King penguin chicks - held cold acclimated or thermoneutral control - ambient temp reduced and thermoneutral control increased their mr at a significantly higher temp, shivering at same point as mr increased

Avian UCP protein homolog found, increased expression as temp dropped.

Hummingbirds closely related UCP, however largest expression during torpid period

Question 5

Bear dormancy

Answer 5

Hyperphagia - torpor very shallow - animals bulk microclimate - Body temp very slight reduction - reduction in water loss by not urinating

Hibernation in black bears - small drops in body temp and spikes in O2 consumption - temp not related to mr due to large size and microclimate

Question 6

Torpor examples

Answer 6

Stripe-faced Dunnart: body temp reduces 20 degrees, as ambient temp drops do does torpid temp

Elephant shrews

Great tit and willow tit

Red billed hoopoe - O2 consumption differs at different temp