Lecture 15 Flashcards
what is physiological ecology
the study of how organisms acquire energy and nutrients and tolerate physical conditions
- ecophysiology
what is homeostasis
constant internal environment when the external environment is changing
- this requires energy
- chem rxn in body need a certain temp –> if the body cannot create that temp then = fails
T/F animals near the poles have wider variation of temperature tolerance
true
the higher latitude of living = wider range
poikilotherms
reptiles, amphibians, fish
they lack the physiology
temps fluctuate a lot
rely on environmental temperature
- they use behavioural means
- moves places to warm or cool
- eats less bc they have low energy requirements
homeotherms
must regulate heat balance to keep internal temp within a narrow range
humans = 37 degrees
eats more bc it takes more energy to maintain homeostasis
radiation
heat transferred by electromagnetic radiation
conduction
transfer of heat by direct contact
convection
heat transfer from moving liquid or air
evaporation
efficient cooling from wet surfaces only
-sweat
redistribution
circulatory systems redistribute heat from core to appendages (feet, fingers)
why does size matter to heat balance
larger animals = lower SA and more volume = retains more heat and loses less heat
better for colder environments
smaller animals = high SA and less V = lose more heat then it can retain = best suited for warm environments
what does having a high SA:V ratio mean
small animal
warm environments
lose heat more
what does having a lower SA:V ratio mean
large animal
cold environments
retain heat more than loses
what is Bergmann’s rule
homeotherms tend to be larger at higher lats (colder envs)
-polar bears
why are elephants failing bergmanns rule
elephants = tropical but they have large mass so shouldn’t they be in colder temps
- related to mammoths = colder temps
why does shape matter in a species
a sphere = smallest SA:V ratio = larger animals (Less SA, more V)
- sometimes particular shapes are used for other functions - hunt, mate, eat
what species has the maximum SA:V ratio
gliding snake
= high SA
hard time to stay warm
that’s why it lives in warm environments
what species has the lowest SA:V ratio
american pika
- sits in a spherical position because it lives in cold habitats - spherical = lowest SA so you lose less heat
what is allens rule
homeotherms tend to have smaller appendages at colder environments (higher lats)
- big ears = more heat loss
arctic fox = small ears
why does insulation matter to a species
cold temp = more fur, feathers, insultation, blubber (layer of fat)
- dinos = feathers
T/F insulation is even more important than size and shape
true
why does vascularization matter to a species
in warm climates - the cooling system matters
large appendage = heat escapes
dogs = panting to evaporate heat on wet tongues
what is countercurrent circulation
circulation from core to limbs
arteries = move warm blood from core to appendages
veins = move cold blood from appendages to core
why are weasels living in cold temps but with high SA:V ratios
high SA:V = smaller animals made for the warm
but weasels live in the cold
they have all the wrong adaptions
but NS hasn’t selected out for it because the size and shape of weasels = predation
= tradeoff
- needs lots of energy to maintain heat but is good at catching food to give energy for heat
what are tradeoffs
being good at one thing makes you bad at another thing - it is costly
NS builds on whats already there
