Gas exchange and ventilation in bony fish and insects

Question 1

As organisms get larger, what happens to the size of the diffusion distance?

Answer 1

It increases

Question 2

As organisms get larger, what happens to the size of the surface area?

Answer 2

It increases

Question 3

As organisms get larger, what happens to the size of volume?

Answer 3

It increases

Question 4

As organisms get larger, what happens to the size of the SA:V?

Answer 4

It decreases

Question 5

Why do more active organisms have a greater demand for Oxygen and Glucose?

Answer 5

• more energy is required for more movement
• more ATP must be produced
• more aerobic respiration must occur
• more reactants (glucose and oxygen) is required

Question 6

What are the 4 features of efficient exchange surfaces?

Answer 6

• increased SA
• thin layers
• good blood supply
• ventilation to maintain diffusion gradient (for gaseous diffusion)

Question 7

Why does an increased surface area make an exchange surface more efficient?

Answer 7

Provides the area needed for exchange surface to overcome the limitations of low SA:V ratio

Question 8

Why do thin layers make an exchange surface more efficient?

Answer 8

The distances that substances have to diffuse across are shorter making diffusion quicker

Question 9

Why does a good supply make an exchange surface more efficient?

Answer 9

The greater the difference in concentration the greater the rate of diffusion, a good blood supply means substances are constantly being delivered and removed, maintaining the steep concentration gradient

Question 10

Why does ventilation increase the efficiency of a gas exchange surface?

Answer 10

Helps to maintain a steep concentration gradient