Temperature Relations Flashcards
temperature
a measure of the average kinetic energy of molecules in a mass of substance
heat
the kinetic energy of a substance
niche, fundamental and realised
niche: the limits of environmental variables in which individuals survive, grow and reproduce
fundamental: largest niche (no competition)
realised: actual niche (smaller)
macro climate
they interact with local landscapes to produce microclimates. may be less important than a microclimate to an organism
examples of macroclimate
prevailing weather conditions over a long period of time
- sun’s uneven heating of earth
- interacts with altitude, aspect, vegetation, colour of ground and boulders
- these produce microclimates
why do aquatic environments have thermal stability?
water has specific heat capacity, latent heat of vaporisation and latent heat of fusion
evolutionary trade-off
adapting to one set of environmental conditions reduces a population’s fitness to others
principle of allocation
evolutionary trade-offs are inevitable since organisms have access to limited amounts of energy
- bacteria that live at 20 degrees cannot live at 40 degrees
optimum temperatures
most species preform best in a fairly narrow temperature range. extreme temperatures affect functioning of enzymes
metabolisable energy intake equation
MEI = C - F - U
C - energy consumed
F - feces
U - uric acid
photosynthesis rate
rate peaks in a range of temperatures (optimum range)
acclimation
physiological changes in response to temperature
- how plants can respond
- used in changing seasons
what contributes to a species optimal temperatures?
distributions of species and evolutionary histories
regulating body temperature
many organisms have evolved ways to compensate for variations in environmental temperature by regulating body temperature
metabolic heat
energy released from cellular respiration
conduction
transfer of heat between objects that touch
convection
heat flow between a solid and a moving fluid (person and cold wind)
poikilotherms
organisms that do not regulate body temperature
ectotherms
animals that rely on an external energy source to regulate temperature
- plants and ectotherms use morphology and behaviour to regulate temp
- leaves reflect radiation
- small leaves = large convection
endotherms
organisms that rely on metabolic heat energy - shiver, release hormones etc.
thermal neutral zone
range of temperatures where metabolism stays stable
homeotherms
use metabolic energy for temperature - birds, mammals, some deep-sea fish
- insulated by fat
- don’t expose respiratory surface to ocean
- countercurrent heat exchangers on exposed limbs
flying insects and some fish heat themselves…
by selectively heating parts of their anatomy
how do some organisms survive extreme temperatures?
entering a resting stage
inactivity
- resting in a sheltered space
- survive extreme temperatures
torpor
low metabolic rate and lowered body temperature when food is scarce and nights are cold - hummingbirds
hibernation
reduced metabolism for several months over winter
estivation
hibernation for summer
