Module 3 - Surface Area

Question 1

What products do organisms need to take in?

Answer 1

Oxygen and nutrients

Question 2

What products do organisms need to remove from the body?

Answer 2

Carbon dioxide and urea

Question 3

What is the rate of diffusion different in a single-celled organism.

Answer 3

Substances can diffuse directly across the membranes and have a fast rate of reaction because substances have a small distance to travel.

Question 4

Why is diffusion across the outer membrane slower in a multi-cellular organism?

Answer 4

• Some cells are deep within the body so there’s a big distance between the outside environment.
• They have a low surface area to volume ratio meaning it s hard to exchange enough substances into an organism with a large volume but small surface area.

Question 5

What organisms have a larger surface area to volume ratio

Answer 5

Single-celled organisms or smaller organisms have a larger surface area to volume ratio because a larger surface area is provided to supply a smaller volume of an organism

Question 6

Why do smaller organisms have a high metabolic rate?

Answer 6

Smaller organisms have a high surface area to volume ratio meaning it is easy for them to lose heat, for example through water evaporation. This means that have a high metabolic rate to generate enough heat for the organism to stay warm

Question 7

Why do larger organisms have a lower metabolic rate that smaller organisms?

Answer 7

Larger organisms have a smaller surface area to volume ratio meaning it is hard for them to lose heat. This means the larger organisms have a low metabolic rate because it doesn’t need to generate large amounts of heat.

Question 8

Why might a fox living in a warm environment have large, point ears and a large nose?

Answer 8

The large ears and nose increase the surface area to volume ratio of the fox. This makes it easier for the fox to lose heat so it can stay cool in warm environments

Question 9

Why might a fox living in cold environments have smaller, compact ears.

Answer 9

The smaller, compact ears decreases the surface area to volume ratio of the fox. This makes it harder for the fox to lose heat therefore enabling it to stay warm.

Question 10

What is a behavioural adaptation that a large organism living it hot conditions might do to stay cool?

Answer 10

Bathe in cool water as they find it hard to reduce heat loss naturally. Or lick themselves.

Question 11

What is an adaptation a large organism living in a cold environment my have to reduce heat loss

Answer 11

A thick layer of fur to reduce the amount of heat lost or hibernate through colder seasons