Heat
Thermal energy, W
-heat energy can be transfered
Temperature
- relative measure of thermal energy
- heat follows a temperature gradient; HEAT FLUX (temp gradient)=rate of heat transfer
ambient/environmental temperature (Ta)
- thermal niche for an animal
- niche temp. fluctuates over tide, such as in a tide pool
- temp. varies within a niche and animal movement
body temperature (Tb)
- temp. of an animal
- Tb fluctuates over time and place
- Tb varies for different parts of body
variability of ambient/environmental temperature
- aquatic environments provide less extreme and less variable temperatures
- deepsea +4C
- ocean surface tropical: +35, polar: -2
- intertidal varies from -20 to +35
- rivers and lakes from 0 to 35
- hot springs at +40C
- alpine air, -60, desert air +60
at +60C….
proteins denature, animals die
heat loss by conduction
-transfer of thermal energy within and between media; usually via contact
heat loss by convection
-loss to a MOVING FLUID: breathing air/water, wind chill, U^2
heat loss by evaporation
heat needed to convert liquid water to vapor, such as in sweat or drying
=520 cal/g; 2.2 kJ/g
heat gain by radiation
-transfer of thermal energy by means of electromagnetic radiation
heat flux
- rate of heat energy movement
- (thermal conductivity)*(temperature gradient)
- DISTANCE=creates insulation
- SURFACE AREA=body shape; respiratory organs
- BODY MASS=2pir vs. pir^2
Thermal conductivity
ability of heat energy to MOVE within and between an object(s)
-ie. thermal conductivity of ice is greater than water, which is greater than air, and rocks conduct better than muscle
heat capacitance
- ability to STORE heat energy
- water is 3000x greater than air for storage
- thermal conductivity and heat cap are large determinants of Tb
aquatic environments have less extreme and less variable temperature because…
- high heat capacitance/storage of water
- limited solar influence of and limited mixing in water
- its maximum density @ 4C, meaning it is difficult to go below 4C without supercooling
why is thermal physiology so important?
- temp determines rate of reactions
2. animals have evolved an elevated, regulated, and more narrow Tb starting 200 mya
temp. determines rates of reactions; increasing likelihood of…
- molecular collisions
- weaker weak bonds favoring enzyme/substrate interactions
- faster reactions rates;Mo2; heart rate; Q; digestion
animals rising, regulating, narrowing Tb
- narrow Tb allows more predictable internal environment (think homeostasis)
- survival values higher rates of reaction for greater athleticism, foraging, and processing food
ectotherms
Tb=Ta
-metabolic heat production<heat loss to the environment
ectotherms: poikilotherm
-Tb varies with Ta
ecto: eurytherm
-lives in a large range for Ta
ecto: stenotherm
-lives in small range for Ta
endotherm
Tb>Ta, and stays within a smaller range (=homeotherm)
- metabolic heat production>heat loss to environment
- homeotherm=Tb varies over time
why is terrestrial environment more challenging for an ectotherm?
-temperatures more extreme, and Tb=Ta
why is aquatic environment more challenging for endotherms?
-endotherms must have metabolic heat production>heat loss to environment, and water has high heat conductivity, so heat is lost quicker in water than in air, making it harder to maintain internal temp, which is also narrower in endo
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respiration lec 124
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respiration 223
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respiration 39
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respiration 425
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respiration 531
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respiration 613
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Circulation 116
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circulation 220
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circulation 315
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circulation 419
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circulation 513
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circulation 610
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circulation 76
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circulation 812
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Temperature 127
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Thermal 216
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Temperature 321
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temperature 4: dealing with cold12
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temperature 5: cardiac proteins, heart function, and high temperatures9
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osmoregulation 141
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Osmoregulation 221
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osmoregulation 325
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osmoregulation 430
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osmoregulation 527
