BIO 3302 Lecture Notes - Lecture 20: African Clawed Frog, Mangrove Rivulus, Tropical Fish
15 Dec 2016
School
Department
Course
Professor
False, fish don’t use respiratory compensation bc relative to air breather already experience lots of
ventilation and CO2 levels ae already very low so it's not effective to lower them further.
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Use transport of bicarb ions by the gills.
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A goldfish that drinks lemonade will hyperventilate to blow off CO2
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False, urea doesn’t diffuse across mbs very well… Rh is used for ammonia movements though membranes
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Urea can move through mbs but not well so use urea transporters.
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Rh glycoproteins are required for urea movement across membranes
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Impairs ionic regulation and acid
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base balance bc high concentration of bicarb outside the cell (facilitated
(diffusion mech relies on this.)
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Sketch this ….
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Exposure to water of high pH impairs NH3 excretion, ionic regulation and acid
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base balance in FW fish
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POP QUIZ
HCO3
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False
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Xenopus, the African clawed frog, always excretes urea.
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Strange bc wants to conserve water and excreting urea counters this.
Continues to excrete ammonia from skin even when in water
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The nitrogen excretion strategy of the mangrove rivulus is unusual because
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TOPIC 4
?1 degrees C (avoid freezing)
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<+50 dC to avoid denaturing of proteins
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Tends to reflect envt
Best function over a narrow range
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Eurythermic vs stenothermic
Animals vary in tolerance of temp changes
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Body temps compatible with life
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Q
10
= 2
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3 for biological reactions
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Synchronization of biochemical reactions
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Changes in the relative rates of different reactions
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Thus, essentially all aspects of life are affected by temperature
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Q10 value = full change in rxn rate for 10dC temp change
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Q10 = 3, rate of rxn will triple when T changes by 10 dC
Chemical rxns get faster as T rises
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Why are optimal temperature ranges typically narrow?
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Thermal physiology
HCO3
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HCO3
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HCO3
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LEC 20
November 28, 2016 11:31 AM
ANIMAL PHYS Page 1
Q10 = 3, rate of rxn will triple when T changes by 10 dC
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Physio of animal life extremely dependent on T
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Frogs can freeze solid
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Thermal conformer
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tolerates T
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Behaviourally
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raise T by sun bathing
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Physiologically
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high metabolic rate to generate heat to maintain body T
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Thermoregulate
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control T
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Snow bird
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go somewhere else when T is cold (not impt for course)
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2 strategies:
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Describes animals attempts to regulate body T
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Don’t need to be successful, can be by bhvr or physio
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Thermoregulation
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Stability of Tb / body T
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Poikilo = body T fluctuates with envt T
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Poikilotherms vs homeotherm
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Terminology
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Metabolic production (heat)
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Endotherms use metabolic heat for thermal strategy that is sufficient to use to change body temp
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Ectotherms do not.
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Endotherm vs ectotherm
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Body T varies through body
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Small body mammals, unable to maintain heat all the time.
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Temp = fluctuates, think they're endotherm homeotherm but changes in predictable fashion
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Different across bodies
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Ex tuna/ lambnid sharks
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Maintain heat in swimming muscle, other areas no.
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Maintain temp at one part of body but not at other parts
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Regional
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Temporal vs regional
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HEAT TRANSFER
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Heat in = heat out
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Radiant = ?
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Conductive = from sun
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Heat gained is matched by heat out
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HETEROTHERMY
Poikilo = red
Homeo
Mammals
Birds
Tropical fish
Polar fish
Reptiles
Amphibians
Invertebrates
Fish
Flying
Insects
Naked
Mole rat
ANIMAL PHYS Page 2
Conductive = from sun
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Determined by envt
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Convective = warm wind
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Metabolic heat gain and evaporative loss determined by animal.
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Central (hypothalamic) thermostat
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On limb and face etc.
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Central (hypothalamic) and peripheral sensors
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Initiation of appropriate responses: heat exchange with environment,
evaporative heat loss and/or metabolic heat production
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Tb regulated via negative feedback control systems
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Mammal and reptiles have diff mechs to change T
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Be able to draw a similar diagram for every animal to adjust heat gain or heat lost.
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Cloacal discharge = similar to sweating but diff.
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Mammals can also produce metabolic heat (endotherms) for adjusting T whereas reptiles do not.
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Basic principle: negative feedback loop
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UV
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> visible
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> IR
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Heat derived from E in radiation
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Absorption and re
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radiation
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Longer wave len
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gth = IR radiation
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Most animals cannot see IR radiation, some snakes can.
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E can be absorbed by animals from sun and also re
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radiates E at lower level / longer wavelength
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Source of gain and loss
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Sun bathing = want to be evenly exposed
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SA = true for all heat exchanges
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Terrestrial gain heat from radiation
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Aquatic cannot bc water absorbs radiant E not them
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animals get out of water.
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Medium
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water vs air
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Colour
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light vs dark
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Larger T diff , more heat transfer occurs.
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Temp diff = ex. Clear night vs cloudy night.
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Determinants:
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Radiation
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Direct transfer of E through contact = warm water and hands
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Water vs fat vs air
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Water is good conductor of heat, air is poor so good insulators
Fat is closer to water but not as good.
Aquatic vs terrestrial animals
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This is why body T tends to match envt T, opah is exception.
Aquatic animals, any heat produced is given to water.
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Material
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conductivity
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Seals have a thicker fat layer as insulation to minimize heat loss to water.
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Terrestrial can use air as insulator, trap layer of air next to body as insulation (puffing of feathers
on bird)
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Thickness
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Temp diff, larger T diff , greater heat transfer
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SA
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Determinants:
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Conduction
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Transfer of heater molecules by moving a fluid
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Determinants
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Convection
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HEAT EXCHANGE MECHS
ANIMAL PHYS Page 3
Document Summary
A goldfish that drinks lemonade will hyperventilate to blow off co2. False, fish don"t use respiratory compensation bc relative to air breather already experience lots of ventilation and co2 levels ae already very low so it"s not effective to lower them further. Use transport of bicarb ions by the gills. Rh glycoproteins are required for urea movement across membranes. False, urea doesn"t diffuse across mbs very well rh is used for ammonia movements though membranes. Urea can move through mbs but not well so use urea transporters. Exposure to water of high ph impairs nh3 excretion, ionic regulation and acid-base balance in fw fish. Impairs ionic regulation and acid-base balance bc high concentration of bicarb outside the cell (facilitated (diffusion mech relies on this. ) Xenopus, the african clawed frog, always excretes urea. The nitrogen excretion strategy of the mangrove rivulus is unusual because. Continues to excrete ammonia from skin even when in water.
