3.1 - SA:Vol

Question 1

1. What usually happens to the surface area to volume ratio as the size of an organism increases?

Answer 1

As the size of an organism increases the SA:V of the organism decreases

Question 2

2. What systems do larger organisms have for the exchange and movement of gases?

Answer 2

Respiratory (Lungs) / Circulatory

Question 3

3. What usually happens to the rate of heat loss of organisms as the surface area to volume ratio increases?

Answer 3

The rate of heat loss increases

Question 4

4. What usually happens to the rate of respiration (metabolic rate) as the surface area to volume ratio of a mammal increases?

Answer 4

The rate of respiration increases to maintain body temperature.

NOTE this might not be true for reptiles, amphibians, fish or invertebrates since they do not regulate their body temperature (ectotherms)

Question 5

5. What usually happens to the uptake of oxygen as the surface area to volume ratio of an organism increases? Why?

Answer 5

The rate of uptake of oxygen increases because respiration is occurring at a higher rate.

Question 6

6. Using the answers from all previous questions, write the flowchart starting with SA:Vol ratio and ending with rate of uptake of oxygen

Answer 6

As size of organism decreases  SA:Vol ratio increases  rate of heat loss increases  rate of respiration (metabolic rate) increases to maintain body temperature  rate of uptake of oxygen increases