Size And Surface Areas

Question 1

Surface area to volume ratio of an organism

Answer 1

The smaller the organism the larger the surface area to volume ratio

Question 2

Single celled organisms diffusion

Answer 2

These can diffuse directly into or out the cell through the membrane

Diffusion rate fast as has a short distance

Question 3

Multicellular organisms diffusion rate slow for two reasons

Answer 3

Some cells deep within the body
A big distance between them and the environment

Larger animals have a smaller surface areas to volume ratio
So difficult to exchange enough substances to supply a large volume of animal through a relatively small outer surface

Question 4

What is mass transport

Answer 4

A system that carries substances to and from cells

Question 5

Two things that are inflicted by staying the right temperature

Answer 5

Body size

Body shape

Question 6

Body size

Answer 6

Makes it harder for it to lose heat if it has a large volume but small surface area

So easy for smaller organisms to lose heat as surface area large

So smaller organisms need a high metabolic rate in order to generate enough heat to stay warm

Question 7

Body shape

Answer 7

Animals with a compact shape have small surface area to volume minimising heat loss from their surface

Animals with less compact shape have larger surface area to their volume increasing heat loss

Question 8

There behavioural and physiological adaptations to aid exchange

Answer 8

Smaller mammals may have thick layers of fur or hibernate when weather goes cold

To support high metabolic rates small mammals living in cold regions need to eat large amounts of high energy food such as nuts

Elephants have large flat ears which increase surface area allowing them to lose more heat

Question 9

Why do multicellular organisms have complex systems in gas exchange

Answer 9

To carry the respiratory gases long distances around the body