Transcript Metabolism
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Surface Area to Volume Ratio
Inversely
proportional to size
Length of r
SA:V and allometry
“Allometric” describes when
there is a relationship between
the size of organisms and any of
their features.
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This SA:V relationship is allometric.
•
So is the relationship between
organism weight and SMR.
Length of r
SA:V and metabolism
Total Metabolism
• An elephant uses more O2 than a
mouse, in an hour.
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BUT a gram of mouse uses more O2 than a
gram of elephant in an hour.
Standard Metabolic Rate
• Bigger individuals use more O2 than smaller
individuals, per unit time.
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Per gram body weight, smaller animals use
more O2 than larger animals.
SA:V and metabolism
Can you describe more than one way in which a
lower SA:V affects the metabolism of an animal?
Ectothermy vs Endothermy
(not warm or cold blooded)
Did you know that metabolic rates in mammals =
10x those in reptiles?
Endothermy is expensive!
Metabolism
How do you think ecologists
use information on metabolism?
Can you define…
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Respiration:
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Ventilation:
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Metabolism:
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Manometry:
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SMR:
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Endothermic:
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Ectothermic:
Can you define…
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Respiration: Role of O2 in extracting energy from
organic compounds.
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Ventilation: Pumping air into and out of the body.
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Metabolism: Sum total of all chemical processes in
the body.
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Manometry: Method to measure and quantify
metabolic rates.
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SMR: Standard Metabolic Rate (mL O2/g/h).
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Endothermic: Generates heat internally.
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Ectothermic: Obtains heat from external sources.
Can you answer…
How did you estimate metabolic rates in lab?
What is SMR?
What is the difference between total metabolism and
SMR?
What is an advantage and a disadvantage of the tracheal
system in insects?
Can you answer…
How did you estimate metabolic rates in lab?
(You should know this!)
What is SMR? Energy (O2) used per gram body weight in an
individual. It is a function of body weight.
You can measure through O2…or CO2
What is the difference between total metabolism and SMR?
(You should think about this!)
What is an advantage and a disadvantage of the tracheal
system in insects?
Did you read about
Tidal flow
The amount of air that passes in and out of the lung during
normal respiration.
What is the difference between total lung capacity
and tidal volume?
Take Home Message
All of this boils down to what happens at a cellular level.
Recall: When you bring oxygen into your system, you let
that oxygen oxidize glucose. This takes energy out of
storage and makes it available for ATP synthesis.
Think about this, then think about the insect tracheal
system and our own mammalian system again.