LabBench Activity

Measuring Temperature and Metabolic Rate

The rate of metabolism in ectothermic animals increases as the environmental temperature increases. This rise occurs because the reactants in the cell have greater thermal energy, and many cellular enzymes are more active as temperature increases. This effect is noticeable in a range from approximately 5°C to 35°C; at temperatures much higher than this, enzymes become denatured.

The graph below illustrates the effect of increased temperature on metabolic rate in an aquatic ectotherm, Daphnia magna (water "flea").

What is the relationship between metabolic rate and a 10°C increase in temperature?

The relationship between temperature and metabolic rate is often measured as Q10. If the metabolic rate doubles with a 10°C increase in temperature, then Q10 = 2.