How can hair reduce conductance?
Piloerection and seasonal moults
What is wrong with sweating?
Water and salt loss
What is Bergmann's rule?
Body size increases with latitude/temperature
What is temporal heterothemy?
Times of the year/day where they can afford to be cooler to reduce energy budget
What is the lethal loss of water?
More than 20%
What is active cooling?
Energy expended in cooling
What is daily torpor?
Body temperature drops during the day
What is the formula for the cost of homeothermy?
VO2 = C(Tb - Ta)
How can ears aid evaporation?
Vascularisation, vasodilation, flapping
What is C?
conductance - rate of heat loss from body to the environment
What is interesting about Coyote BMR?
79% in desert. 126% in Alaska
What is endothermy?
The ability to maintain/generate heat through a combination of internal metabolic activity and physiological regulation
What are the costs of not thermoregulating?
Hyperthermia and Hypothermia
How does feeding at night conserve water in oryx?
Parched plants absorb moisture from the air. More water in plants at night
What factors determine conductance?
Insulation, body size and shape.
What is region heterothermy?
Parts of the body maintained at cooler temperature to reduce the cost.
How does migration reduce energy expenditure?
Which animals retain body heat longer?
Larger body size
How does body shape affect heat loss and energy costs?
Long thin animals = low surface area: volume ratio
What is Allen's Rule?
Animals living in more extreme environmental conditions have smaller limbs
What is Ta?
How is an oryx heat and drought tolerant?
Relies on metabolic water, seeks shade
What are the physiological consequences of fossorial living?
Lower Basal metabolic rates. Lower respiratory and heart rates
What is homeothermy?
Heat isn't generated, temperature is just maintained
What are the costs of thermoregulation?
High energy demand
What is basal metabolic rate?
Minimum metabolic rate required to maintain resting function in thermal neutral zone
What is passive cooling?
Basing/shading. Conduction to draw heat off
What is the lower critical temperature?
Point below which the balance between metabolic heat production and heat loss cannot be maintained
Why is sharing a hibernacula good?
Cost free benefit to share
What is evaporative cooling?
Evaporation of fluid from the body surface: sweating, saliva, urination
What do methatheria and eutheria BMR vary?
Methatheria have a lower BMR. Eutheria is higher from the selection for high reproductive rates
How is a camel heat and drought tolerant?
Thermal interia, rapid heat loss at night. Interstitial intracellular fluid
What is heterothermy?
Varying body temperatures
How do food habitats affect BMR?
Foliovores, soil/litter, ant/termite have low Small/aquatic carnivores have high
What is the upper critical temperature?
Point above which metabolic work is needed in order to dissipate heat by evaporative cooling and maintain constant temperature
Why homeothermy evolve?
Selective pressure for sustained activity and reduced body size
What is the principle function of hair?
Which does larger body size mean great thermal interia?
Less energy is required for cooling and heating
How can water be conserved?
Kidney, gut, lactation, diet, behaviour, respriation
What is thermal inertia?
Degree of slowness with which the temperature of a body approaches that of its surrounding
How can mammals display heterothermy?
Regionally (within the body), temporally (over time)
What is thermal neutral zone?
When little or no metabolic energy is expended on temperature
How does a kangaroo rat survive?
Reliant on metabolic water from seeds. Nocturnal. Concentrated milk
What is the thermal neutral zone of most mammals?
What is metabolic water?
By-product of aerobic metabolism
What are the benefits of homeothermy?
Homeostasis, continouous activity
How do animals conserve energy?
Minimise conductance through insulation
What is hibernacula?
Place of abode in which creature hibernates
What is sub-cutaneous fat?
Layer of fat found just beneath the skin, insulation and energy
How does body size effect heat loss and energetic costs?
Larger animals have lower Area: volume ratio
What is monotremes body temperature?
lower, just above 30
Which is better panting or sweating?
How long do edible dormice hibernate for?
What is active heating?
Energy expended in generating heat
How do fur seals lose heat?
Finning - flapping fins which sweat to increase evaporative cooling
What is Tb?
Variation in body temperature
What is seasonal torpor?
Prolonged drop in body temperature triggered by food variation, decline in day length, low temperatures