size and surface area

Question 1

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

Answer 1

1. larger animals have a small SA:vol ratio
2. faster rate of diffusion

Question 2

use your knowledge of surface area to volume ratio to explain the higher metabolic rate of a mouse compared to a horse (3 MARKS)

Answer 2

1. mice have a larger SA:vol ratio compared to horses
2. mice lose heat faster
3. faster metabolic rate releases more heat

Question 3

describe the relationship between size and surface area to volume ratio of organisms (1 MARK)

Answer 3

the larger the organism, the smaller the SA:vol ratio

Question 4

explain why oxygen uptake is a measure of metabolic rate in organisms (1 MARK)

Answer 4

oxygen used in respiration which provides energy