Thermoregulation - concepts and mechanisms Flashcards
What types of adaptations can an animal make to variations outside of its optimal temperature range?
Behavioural
Physiological
What is the main disadvantage of being a homeotherm (endotherm)?
The have a higher metabolic rate than a poikilotherm so need a higher level of food consumption.
How can heat be produced/gained?
Increasing metabolism
Muscle contraction - shivering
- exercise
Non-shivering thermogenesis
Change to environmentWhat are the two categories of how heat can be lost?
Evaporative heat loss
Non-evaporative heat loss (sensible heat loss)
What does the ‘metabolic rate’ refer to?
The heat produced from oxidative metabolism within the body.
Why do bigger animals have a lower metabolic rate?
They have a larger surface area to volume ration and don’t need to produce as much heat per unit of body mass to maintain an overall temperature.
What are the factors to consider when an animal is endo or ectothermic?
- Level of activity
- Their dependence on the environment
- Metabolic rate vs. the cost to maintain this
- Variation in ambiant temperature
- Availabilty of food
- Ability to regulate through behaviour
- Insulation
What are the sources from which an animal may gain heat from the environment?
Infrared radiation either from the sun or solid objects.
Which animals pant or sweat etc?
Horses and cattle sweat
Pigs and dogs mainly pant
Sheep use both methods
Birds “gular flutter”
What do animals try to affect by altering their behaviour with changing temperatures?
Hot - increase non-evaporative heat loss and evaporative heat loss
cold - reduce sensible heat loss
What are the ranges of temperature within the thermoneutral zone?
Warm, cool and optimum.
What do upper critical temperature and lower critical temperature?
These are the top and the bottom end of thermoneutral zone respectively.
What are the features of group 2 animals (ruminants) which make them different to group 1 animals?
They have a much larger range of environmental temperatures that are considered optimal. This is partly due to their increased abiltiy to lose evaporative heat due to sweat, for example.
