Temperature 1 Flashcards
how does thermal energy affect animals (2)
- influences chemical interactions that affect macromolecular structure and biochemical reactions
- affect shape and function of all proteins, including enzymes
what equation is used to describe the effects of thermal energy on animal functions
- Van’t Hoff equation
Van’t Hoff equation (2)
- Q10 = (k2/k1)^10/(t2-t1)
Van’t Hoff equation: k2 and k1
- rates of the reaction at two different temperatures
Van’t Hoff equation: t2 and t1
- two different temperatures
Van’t Hoff equation: simplified (2)
- for exactly 10 C change
- Q10 = k2/k1
what are the Q10 values for more chemical reactions (metabolism, growth, locomotion) (2)
- 2-3
- reaction doubles or triples with a 10 C change in temperature
what are the Q10 values for a purely physical process (diffusion) (2)
- closer to 1.0
- temperature effects are more minimal
what is temperature often referred to
- ecological master factor
thermal strategy
- combination of behavioral, biochemical, and physiological responses that ensure body temperature is within an acceptable limit
ambient temperature (2)
- temperature of the animal’s surroundings
- most important environmental influence on the animal’s thermal strategy
what thermal factors must animals be able to survive (2)
- thermal extremes
- thermal changes over days, seasons, etc
what kind of temperature changes do ecosystems experience (2)
- spatial variation in temperature
- temporal variation in temperature
what are the ranges of temperatures in terrestrial life
- 60 C to +60 C
what are the ranges of temperatures in aquatic life
- 2 C to +40 C
why do fish have poor freezing temperature tolerance
- fish cannot survive in ice, so there is no selection for freezing temperature tolerance
what are the two major thermal strategies (2)
- tolerance
- regulation
thermal strategy: tolerance
- body temperature is allowed to vary with ambient temperature
thermal strategy: regulation
- body temperature does not vary with ambient temperatures
what is body temperature a reflection of
- the thermal energy of the molecules in the body
describe the movement of thermal energy/heat fluxes (3)
- can move between animals and the environment
- thermal energy moves “down” a temperature gradient
- many sources and sinks of thermal energy
what types of thermal energy contribute to total thermal energy (5)
- metabolism
- conduction
- convection
- radiation
- evaporation
conduction
- transfer of thermal energy from one object or fluid to another
heat flux symbol
Q
heat flux
- rate of transfer from warm to cold
heat flux equation name
- Fourier’s law
Fourier’s law
Q = λ * ΔT / L
Fourier’s Law: λ
- thermal conductivity
Fourier’s Law: ΔT
- temperature gradient
Fourier’s Law: L
- distance over which the gradient extends
heat transfer mechanisms (4)
- conduction
- radiation
- convection
- evaporation
heat transfer mechanisms: conduction (2)
- gain or loss to the environment
- transfer by direct contact
heat transfer mechanisms: radiation (2)
- gain or loss to the environment
- transfer by means of electromagnetic radiation
heat transfer mechanisms: convection
- gain or loss to the environment
- transfer to a moving medium
what are examples a moving medium during convection (2)
- breathing air or water
- wind chill
heat transfer mechanisms: evaporation
- heat loss to the environment
- transfer as a result of the latent heat of evaporation
what are examples of the latent heat of evaporation (3)
- sweating
- breathing
- drying
why does sweating help to cool us down (2)
- converting water from liquid to vapor uses energy
- by covering body with water, it will evaporate and use energy to cool us down
what aspects of our anatomy can change the rate of heat exchange (2)
- surface area
- surface insulation
which organs are better at transferring heat (2)
- respiratory organs
- high surface area and low surface insulation
what is the role of behaviour in heat transfer mechanisms
- behaviour can alter rates of heat exchange
what are the major determinants of heat exchange via conduction (2)
- thermal conductivity
- heat capacitance
thermal conductivity
- ability of heat energy to move within material
how are thermal conductivity and insulation related
- high conductivity = poor insulation
heat capacitance
- ability to store heat energy
what is the heat capacitance in water vs air (2)
- water can store 3000x more heat than air
- water is considered a heat sink
what do thermal conductivity and heat capacitance influence (3)
- life in water vs air
- insulation materials
- behaviour
how does the SA:V ratio affect heat exchange
- high ratio increases rates of heat exchange
compare the rates of heat exchange between large and small animals
- large animals exchange heat more slowly than small animals
Bergmann’s rule
- mammals and birds living in cold environments tend to be larger
Allen’s rule
- mammals and birds in colder climates have smaller extremities
what behaviours can affect SA:V ratio
- body posture
- huddling behaviour
how does body posture affect heat exchange
- can alter the exposed surface area
how does huddling behaviour affect heat exchange
- reduces effective surface area for heat exchange
insulation
- layer of material that reduces thermal exchange
internal insulation
- insulation under the skin
internal insulation: example
- blubber
external insulation
- insulation on the body surface
external insulation: examples (4)
- hair
- feathers
- air
- water
what determines the effectiveness of insulation
- depends on the thickness
what terms are used to describe the relative stability of body temperature (2)
- piokilotherm
- homeotherm
poikilotherm
- variable body temperature
homeotherm
- stably body temperature
what are terms to describe the sources of thermal energy in animals (2)
- ectotherm
- endotherm
ectotherm
- environment determines body temperature
endotherm
- animal generates internal heat to maintain body temperature
what animals are commonly classified as endothermic, homeotherms (2)
- mammals
- birds
what animals are commonly classified as ectothermic poikilotherms (4)
- amphibians
- reptiles
- fish
- invertebrates
what animals are homeothermic ectotherms
- environment determines body temperature, but the environmental temperature is very constant
what animals are endothermic poikilotherms
- animals that experience a range of temperatures as they use their endothermy for specific situations (before flight, etc)
