3.1 - Surface area to volume ratio

Question 1

What is the relationship between the size/structure of an organism and its surface area to volume ratio?

Answer 1

as size increases, surface area to volume ratio decreases

Question 2

Why do organisms with a large SA:vol ratio have a high metabolism?

Answer 2

high heat loss from exchange surface so high metabolism/respiration rate to replace heat

Question 3

Name features of an efficient exchange surface and why they are important

Answer 3

• large SA: gas exchange
• thin: short diffusion distance
• good blood supply/ventilation: maintain steep gradient