seminars 5, 6, 6pt2

Question 1

compared to hypoxia tolerant vertebrates, anoxia tolerant vertebrates generally stay at lower body temperatures. why may this be?

Answer 1

higher body temperatures in hypoxia tolerant vertebrates indicate higher metabolism rates - they work harder to survive, and deplete what little oxygen is left

Question 2

in anoxic conditions, goldfish don’t make lactic acid, but rather ethanol. what advantage might this have?

Answer 2

ethanol is not poisonous, so there may be an advantage there

Question 3

compare cost of metabolism to cost of transport

Answer 3

metabolic rate: energy per unit of time

cost of transport: energy per unit of distance

Question 4

what is the diff bw:
- endotherm vs ectotherm
- poikilotherm vs homeotherm
- eurytherm vs stenotherm

Answer 4

how heat is produced:
- endotherm (heat prod inside body)
- ectotherm (heat prod outside the body)

how body temp changes:
- poikilotherm (variable body temp)
- homeotherm (constant body tem)

range of ambient temp survival:
- eurytherm (wide range of temps)
- stenotherm (narrow range of temps)

Question 5

can an endotherm be a poikilotherm? if so, how?

Answer 5

endotherm: internal heat prod
poikilotherm: variable body temp

can vary w metabolic changes like torpor or hibernation

Question 6

when lizards are acclimated to cool temperatures from higher temperatures, their metabolic rate is different from before. what is this difference, and why does it occur?

Answer 6

metabolic rate will be higher than before (lower metabolic rate if moving from lower temp to higher temp)

this occurs due to

Question 7

what is aerobic scope?

Answer 7

(max metabolic rate) - (resting metabolic rate)
max MR does not change, but resting MR does based on ambient temp
– as environ temp incr, aerobic scope decr ie more oxygen is consumed

Question 8

enzyme affinity can be argued to be either variable bw species, or nonvariable w species. explain both arguments

Answer 8

variable: if u look at diff species, they are adapted for diff temperatures

nonvariable: while animals are adapted for diff temps, we see that they all converge around the same range

Question 9

what are two major problems assoc w ice formation?

Answer 9

• sharp: some energy must be devoted to cell recovery
• concentrates solutes outside of cell (esp when seawater freezes) – cell needs to account for sudden hyposmolarity and subsequent dehydration risk

Question 10

how do AFPs work?

Answer 10

anti freezing prots prevent ice from being formed. ice needs something to build off - otherwise it is just cold water. AFPs prevent this initial instance of ice from being formed.

Question 11

what is BAT and UCPI?

Answer 11

Brown Adipose Tissue is tissue that is high in mitochondria that produces a lot of heat. this is using Uncoupling Protein I, which uncouples ATP synthase from the ETC - proton gradient is used for heat rather than energy.

Question 12

what is regional heterothermy? what purpose does it serve?

Answer 12

regional heterothermy is the idea of keeping diff parts of the body at diff temps.

to heat up the entire body to be uniform would require excessive amts of energy (SA:V is inefficient in this sense)

as well, lots of heat gets lost at the extremities so its largely jus really inefficient

Question 13

how does counter current exchange work?

Answer 13

warm blood moves to the extremities, where it gets cooled by ambient temps and returns as cooled blood. counter current heat exchange uses some of the heat of blood moving to the extremities (that will get lost to the environment anyways) to warm up the cooled blood, since it will req less energy later

Question 14

how does rete mirable use the principle of CCE?

Answer 14

blood is cooled before it reaches the brain.
reindeer usually run pretty hot bc of their fur coats. if they need to incr metabolism, they risk overheating; by cooling blood going to the brain, they decr this risk.

Question 15

how do tropical and arctic species differ in metabolic rates

Answer 15

tropical often have significantly higher metabolic rates due to working harder to maintain metabolism [which is why we prob see more ectotherms]

Question 16

how do bluefine tuna use counter current exch?

Answer 16

muscles need to run hot, so incoming blood is heated up by outgoing blood that is alr really warm

Question 17

how do regulators vs conformers fare in hyperosmotic environ?

Answer 17

regulators stay constant while conformers match the environ (isocline)

Question 18

why is the urine:plasma ratio important? how can it be used to indicate the environment an animal is living in?

Answer 18

urine:plasma ratio is the ratio of conc in an animal’s blood. if U:P > 1, urine is more conc, and the animal likely lives in an arid/SW environ. if the U:P < 1, urine is less conc, and the animal likely lives in a FW environ

Question 19

how does O2 uptake in fish utilize CCE?

Answer 19

ok so basically how it works is that water flows in gills, and oxygen-poor blood flows the opposite direction. there are two conc gradients at play here: a gradient for oxygen to flow inwards since blood has low oxygen, and a gradient for CO2 to flow outwards since blood is high in CO2

Question 20

in fish gills, where are MRR most plentiful?

Answer 20

primary lamellae, where ion transport is done
its on the sides where there’s most active transport of NaK to build up Na+ gradient inside the cell (also to take up some Ca)