Prelim 2 Biog1440 Flashcards
Temperature
A measure of the speed of the random motions of the atoms or molecules in a substance
Heat
The total energy that a substance possesses by virtue of the sum of random motions of its atoms or molecules
Most biochemical and physiological components are temperature…
Sensitive (ex. functional proteins become denatured and cannot function when it is too hot)
Q10
A quotient describing the sensitivity of a process to temperature (ex. how sensitive an enzyme is to temperature change)
Q10 Formula
Q10= R under(t+10 degrees C)/Runder(T)
Endotherms
Most of the heat in this organism comes from metabolism
Ectotherms
Temperature of the body is mostly dependent on the environment
Endotherms that regulate body temperature
Homeotherms are thermoregulating (e.g. birds/mammals)
Endotherms that don’t regulate body temperature
Non-thermoregulating endotherms (e.g. naked mole rat)
Ectotherms that regulate heat
Behavioral thermoregulators (e.g. moths pre-flight)
Ectotherms that don’t regulate body temperature
Polikilotherms are non-thermoregulating ectotherms (e.g. fish, bugs, etc.)
Heterotherms
Endotherms but they choose to regulate at certain phases of their life cycles and not regulate at others (e.g. bats, hummingbirds)
Heat Exchange Equation
Tbody=Tambient + Hmetabolism +/- Hradiation +/- Hconduction +/- Hconvection - Hevaporation
Radiation
- Radiative heat can be gained or lost
- All objects warmer than absolute zero emit radiation and lose energy
- Energy is lost/gained as infrared electromagnetic waves
What does radiation depend on?
Stefan-Boltzmann Law: Hrad=emissivity * theta * Area * (T1^4-T2^4)
- The difference in temperature of the two surfaces
- The surface area of the objects (huge for small animals)
- The color (the emissivity of the surface)
Conduction
- Conductive heat can be gained or lost
- Conduction is the direct transfer of kinetic energy of molecular motion and requires physical contact of the object with either a solid, a liquid, or a gas
What does conduction depend on?
Hcond=Conductivity Area(Tsurface1-Tsurface2)/Thickness
- The difference in temperature of the two surfaces
- The area of contact
- Thermal conductivity (how well the surfaces conduct heat)
Convection
- Convective heat can be gained or lost
- Convection is a transfer of heat by mass flow within a fluid medium, such as air or water
In practice; however, the vast majority of cases involve convection cooling by the organisms losing heat to a medium moving past it.
What does convection depend on?
Hconv= convection coeff * Area * (Tsurface-Tambient)
- The surface area of contact
- Temperature difference between the object and medium
- And rate of flow of the medium
Evaporation
- Evaporation always takes heat from the body
- The change in phase from liquid to gas requires energy (vaporization heat). This energy is removed from the object which the liquid leaves.
What does evaporative cooling depend on?
Hevap=Volume water vap/(Ta * relative humidity)
- The volume of water evaporated
- The humidity of the ambient air
What does metabolism depend on?
Metabolism depends on volume because if you have many cells in your organisms, you will have a lot of metabolic heat
Radiation, conduction, convection, & evaporation all depend on the …
Surface of exchange
You gain heat mostly by …
Volume