StemUp: AQA A level Biology 3.3.1 Surface area to volume ratio

What is the relationship between the size of an organism and their SA:V? (1)

As the size of an organism increases, the surface area to volume ratio decreases

Describe why a smaller animal will have a higher metabolic rate compared to a large animal (3)

- Smaller animal will have a much greater SA:V

- So will lose a greater amount of heat energy per gram of mass

- Therefore, they will need to respire more rapidly to replace heat energy loss

Why is oxygen uptake a measure of metabolic rate in organisms? (2)

- Oxygen is used in aerobic respiration

- Which provides energy for metabolic reaction

Explain the advantage for larger animals having a specialised system that facilitates oxygen uptake (2)

- Larger organisms have a smaller SA:V

- Specialised systems will overcome the long diffusion pathway in these organisms

How you calculate the surface area of a cube? (1)

6 x l^2

Where l = length of one side

How you calculate the volume of a cube? (1)

l x l x l

Where l = length of one side