lect - thermoregulation

Question 1

endotherm

Answer 1

defends fix body temp

Question 2

ectotherm

Answer 2

changes body temp with environment
eg. reptiles + amphibians

Question 3

the Bogert effect

Answer 3

thermal tolerance limits evolution at different rates
- easier for diurnal species to evolve cold tolerance than heat tolerance

Question 4

thermoregulation

Answer 4

gaining + losing heat

Question 5

thermoregulatory strategies

Answer 5

• heliothermy (heat from sun)
• thigmothermy (heat from conduction)
• thermoconforming
• mesothermy (metabolic heat)
  *species are not constrained to a specific strategy

Question 6

heliothermy

Answer 6

1. shuttling = movement between sun and shade
   eg. foraging lizards
2. postural = changing exposure to sun (changing angle)
   eg. sit + wait lizards
   - most lizards, crocs, and turtles

Question 7

thigmothermy

Answer 7

absorbing heat directly from surfaces by conduction
- many nocturnal geckos, snakes, and most fossorial species

Question 8

thermoconforming

Answer 8

attempt to regulate body temp separate from environment temp
- evolve physiology to function in lower temperatures
eg. tropical rainforest species

Question 9

mesothermy

Answer 9

a species that can modulate body temp with metabolic heat, but does not have a fixed body temperature
eg. leatherback turtles

Question 10

losing heat

Answer 10

primarily evaporation (water loss)

Question 11

hygroregulation

Answer 11

balance internal body heat with their water balance during thermoregulation

Question 12

thermoregulation in amphibians

Answer 12

need to balance thermoregulation and desiccation with their permeable skin
- generally, frogs can withstand higher temps, they tend to minimize water loss rather than thermoregulate

Question 13

thermal plasticity

Answer 13

thermal preferences can change rapidly with acclimation

Question 14

thermoregulation importance

Answer 14

• constraints on defence
• constraints on activities involving cold habitats
• constraints on activity periods
• constraints on defence strategies
• choice of shelter site
• forced risk-taking behaviour

Question 15

ectothermy pros/cons

Answer 15

cons
- performance affected by environment temp
- restricted in cold habitats
- behaviour constrained by thermoregulation
- poor endurance
pros
- lower energy requirement
- higher pop density / food availability
- greater flexibility in body shape

Question 16

endothermic pros/cons

Answer 16

cons
- higher energy requirement
- lower pop density / food availability
- surface:volume ratio restricted
pros
- performance unaffected by environment temp
- better in cold habitats
- few. behavioural constraints by thermoregulation
- sustained power