Reading Assignment: Chapter 6--Hydromineral Balance end.
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Transcript of Reading Assignment: Chapter 6--Hydromineral Balance end.
Reading Assignment:
• Chapter 6--Hydromineral Balance
end
Thermoregulation:
• Cold-blooded -poor descriptor
• Poikilotherm (n); poikilothermic (adj)– variable body temperature– opposite = homeotherm
• Ectotherm (n); ectothermic (adj)– temp. determined by environment– opposite = endotherm
end
Why are fishes ectothermic?Heat generated by metabolism
skin
bodygills
end
Behavioral Thermoregulation
• nearly all fishes
• choose from available temperatures
• concept of temperature preference
end
Temperature Preference:
Temperature C0 4020
Freq
uenc
yPreferred Temperature
eurytherm
stenotherm
end
Temperature Preference continued:
Temperature C0 4020
Freq
uenc
yPreferred Temperature
cold adapted
warm adapted
end
Temperature C0 4020
Freq
uenc
yPreferred Temperature
Temperature Preference continued:
The effect of Acclimation
end
0 4020Acclimation Temperature C
Pref
erre
d Te
mpe
ratu
re C
Temperature Preference continued:The effect of Acclimation
20
0
40final preferred temperature
bluegill
temperature tolerance
end
0 4020Acclimation Temperature C
Pref
erre
d Te
mpe
ratu
re C
Temperature Preference continued:The effect of Acclimation
20
0
40final preferred temperature
chum salmon
bluegill
guppy ???
end
Physiological Thermoregulation
• few fishes--tunas & lamnid sharks
• fish are active --generate heat
• rete mirabile for heat exchange & conserv.
• fish are large--low surface area to mass ratio– body surf. area increases as square of length– body mass increases as cube of length
end
Physiological Thermoregulation
body
skin
skingills
heat
rete mirabile
end
Counter-current blood flow
Distance along capillaries (rete)
Tem
pera
ture
low
high
arterial blood
venous blood
heat
from gills
from body
end
typical
fish
tuna
Counter Current flow:
• fluid flowing in opposite directions
• exchange of heat or gas perpendicular to flow
• efficiency versus speed
end
Distance along capillaries (rete)
Tem
pera
ture
low
high
Hypothetical Co-current blood flow:
from gills
from body
arterial blood
venous bloodcounter-current
heat
end
Hypothetical Co-Current flow:
• fluid flowing in same direction
• exchange of heat or gas perpendicular to flow
• speed versus efficiency
• vessels naturally flow in opposite direction
end
end
Hydromineral Balance: Life in a solvent
Environmental forces cause movement of water and dissolved substances
versus
Homeostasis--the need to maintain balance of water and dissolved substances in cells and body fluids of organisms
-constant internal environment
end
Environmental forces:• heat--(movement of molecules) energy for
movement
• diffusion--net movement of molecules
• pressure--density of molecules – difference causes or blocks movement
• osmosis--movement of water
• electrochemical forces--attraction & repulsion of molecules based on charge
end
• Environmental forces work together toward equilibrium
• equilibrium-no net movement of molecules
end
end
Lecture Exam Monday
• 100 point exam
• covers lectures, assigned readings
• 8-12 short answer questions; 4-6 pts ea– complete, concise answer– ex: definition
• 3-5 longer questions; 10-15 pts ea
• Finish by 1:55--budget time
• Power Point lectures at: http://www.und.nodak.edu/instruct/skelsch/425~1.htm