3.3.1 Surface area to volume ratio

Question 1

How does an organism’s size relate to their surface area to volume ratio

Answer 1

The larger the organism, the lower the surface area to volume ratio

Question 2

How does an organism’s surface area to volume ratio relate to their metabolic rate

Answer 2

The smaller the surface area to volume ratio, the higher the metabolic rate

Question 3

How might a large organism adapt to compensate for its small surface area to volume ratio

Answer 3

Changes that increase surface area eg folding
body parts become larger eg elephants ears
elongating shape
developing a specialised gas exchange surface

Question 4

Why do multicellular organisms require specialised gas exchange surfaces

Answer 4

Their smaller SA:V ratio means the distance that needs to be crossed is larger and substances cannot easily enter the cells as in a single-celled organism