Question

multiple choice 5 points
respirometer is a container used to measure the amount of oxygen consumed by an organism. a respirometer was used to determine how environmental temperature affects the uptake of oxygen in one 300 - gram rat and one 50 - gram mouse. the results of this experiment are shown on the graph below.
which of the following hypotheses is best supported by the results of this experiment?
mice produce less co2 per gram of tissue than do rats
metabolic rate per gram of tissue is not related to body mass.
rats consume more food per gram of tissue than do mice.

Explanation:

The graph shows the relative amount of \(O_2\) consumed per gram of tissue over time. Mice (both at \(15^{\circ}C\) and \(20^{\circ}C\)) consume more \(O_2\) (higher metabolic rate as \(O_2\) consumption is related to metabolism) than rats (at \(20^{\circ}C\) and \(12^{\circ}C\)) over time. Since \(O_2\) consumption is related to metabolic rate and food consumption (as food is broken down using \(O_2\) in respiration), and the graph shows mice consume more \(O_2\) (higher metabolic rate), it implies mice would consume more food per gram of tissue. Also, since \(O_2\) consumption and \(CO_2\) production are related (in respiration, \(O_2\) is consumed and \(CO_2\) is produced), higher \(O_2\) consumption (mice) would mean more \(CO_2\) production. The graph shows that at a given time, the \(O_2\) consumption (related to metabolic rate) per gram of tissue for mice is higher than for rats. So the hypothesis that rats consume more food per gram of tissue than do mice is not supported. The metabolic rate (related to \(O_2\) consumption) per gram of tissue for mice is higher (so it is related to body mass as mice are smaller, higher surface - area - to - volume ratio, higher metabolic rate). And since \(O_2\) consumption is higher for mice, \(CO_2\) production (as \(CO_2\) is a product of respiration where \(O_2\) is consumed) would be higher for mice per gram of tissue.

Answer:

Rats consume more food per gram of tissue than do mice.