Lecture 15

Question 1

what is physiological ecology

Answer 1

the study of how organisms acquire energy and nutrients and tolerate physical conditions
- ecophysiology

Question 2

what is homeostasis

Answer 2

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

Question 3

T/F animals near the poles have wider variation of temperature tolerance

Answer 3

true
the higher latitude of living = wider range

Question 4

poikilotherms

Answer 4

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

Question 5

homeotherms

Answer 5

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

Question 6

radiation

Answer 6

heat transferred by electromagnetic radiation

Question 7

conduction

Answer 7

transfer of heat by direct contact

Question 8

convection

Answer 8

heat transfer from moving liquid or air

Question 9

evaporation

Answer 9

efficient cooling from wet surfaces only
-sweat

Question 10

redistribution

Answer 10

circulatory systems redistribute heat from core to appendages (feet, fingers)

Question 11

why does size matter to heat balance

Answer 11

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

Question 12

what does having a high SA:V ratio mean

Answer 12

small animal
warm environments
lose heat more

Question 13

what does having a lower SA:V ratio mean

Answer 13

large animal
cold environments
retain heat more than loses

Question 14

what is Bergmann’s rule

Answer 14

homeotherms tend to be larger at higher lats (colder envs)
-polar bears

Question 15

why are elephants failing bergmanns rule

Answer 15

elephants = tropical but they have large mass so shouldn’t they be in colder temps
- related to mammoths = colder temps

Question 16

why does shape matter in a species

Answer 16

a sphere = smallest SA:V ratio = larger animals (Less SA, more V)
- sometimes particular shapes are used for other functions - hunt, mate, eat

Question 17

what species has the maximum SA:V ratio

Answer 17

gliding snake
= high SA
hard time to stay warm
that’s why it lives in warm environments

Question 18

what species has the lowest SA:V ratio

Answer 18

american pika
- sits in a spherical position because it lives in cold habitats - spherical = lowest SA so you lose less heat

Question 19

what is allens rule

Answer 19

homeotherms tend to have smaller appendages at colder environments (higher lats)
- big ears = more heat loss
arctic fox = small ears

Question 20

why does insulation matter to a species

Answer 20

cold temp = more fur, feathers, insultation, blubber (layer of fat)
- dinos = feathers

Question 21

T/F insulation is even more important than size and shape

Answer 21

true

Question 22

why does vascularization matter to a species

Answer 22

in warm climates - the cooling system matters
large appendage = heat escapes
dogs = panting to evaporate heat on wet tongues

Question 23

what is countercurrent circulation

Answer 23

circulation from core to limbs
arteries = move warm blood from core to appendages
veins = move cold blood from appendages to core

Question 24

why are weasels living in cold temps but with high SA:V ratios

Answer 24

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

Question 25

what are tradeoffs

Answer 25

being good at one thing makes you bad at another thing - it is costly
NS builds on whats already there