1. Whole-Animal Metabolism
Animals require chemical energy for:
activity (muscular work)
synthetic activities
heat production (in endotherms)
How can we determine how much energy an
organism requires and uses for these activities?

2. Look at heat production:
Burn 1 mol (180g) of glucose in a calorimeter*:
1 mol glucose + 6 mol O mol CO2 + 6 mol H2O +
686 kcal (heat)
Metabolize 1 mol of glucose aerobically in an animal:
1 mol glucose + 6 mol O mol ADP + 38 mol Pi
6 mol CO mol H2O + 38 mol ATP kcal heat
266 kcal

3. Eventually, all the chemical energy in the
organism will be released as heat -
regardless of the food source.
Therefore, Rate of heat production = Metabolic rate = Em
Holds for all organisms that are not growing

4. Carbon dioxide expiration
Again, assuming an organism is respiring
aerobically, what alternative measures
might we use to approximate the
metabolic rate?
Hint:
1 mol glucose + 6 mol O mol ADP + 36 mol Pi
6 mol CO mol H2O + 36 mol ATP kcal
Answer?
Oxygen consumption
Carbon dioxide expiration

5. Oxygen/carbon dioxide relationships
Ratio of CO2 prod. / O2 consumed = respiratory quotient = R.Q.
Carbohydrates
C6H12O6 + 6 O CO2 + 6 H2O
R.Q. = 6 CO2/ 6 O2 = 1.00
Fat
2 C51H98O O CO H2O
R.Q. = 102 CO2 / 145 O2 = 0.70
Protein
R.Q. = 0.80

6. if you wish, you can use 4.8 kcal • l O2-1)
1 Joule = cal
Kcal/liter O2
______
5.0
4.7
4.5
if you wish, you can use 4.8 kcal • l O2-1)
Assumes a mixed diet

7. Numerous physical and behavioral factors
affect metabolic rate:
size
temperature & season
hibernation & torpor
salinity
photoperiod & tidal cycle
pressure of oxygen
activity

8. Definitions: Basal metabolic rate (BMR) - minimal rate of metabolism
for a fasting, inactive individual (with no heat prod.
for homeotherm).
Standard metabolic rate (SMR) - rate for an individual
at rest at a given temperature.
Active metabolic rate (AMR) - rate for forced, maximal
activity at a given temperature.

9. Locomotion is expensive:•
Activity vs. VO2
Locomotion is expensive:
In humans, VO2 can increase X during exercise
In insects, VO2 can increase X during flight: •

10. activity (e.g. swimming speed)•
VO2’
SMR
activity (e.g. swimming speed)

11. Expressed as dimensionless value (e.g., 8)
Metabolic Scope for Activity = AMR / SMR
Expressed as dimensionless value (e.g., 8)
Goldfish (ml O2 • kg-1 • h-1)
280 40
VO2’ •
Temp. (°C)
0 40
AMR
SMR

12. velocity (lengths • s-1)
Cost of Locomotion
VO2 liters O2 • kg-1 • h-1
C.L. = = = liters O2 • kg-1 • km-1
velocity km • h-1 •
C.L.
Salmon
velocity (lengths • s-1)

13. running
flying
C.L.
swimming
Body Mass (kg)