3. Surface Area to Volume ratios

Question 1

Ficks Law

Answer 1

Question 2

Heat and SA;V

Answer 2

Organisms also need to exchange heat with their surroundings. The larger the surface area to volume ratio, the more heat is lost to the environment. That is why the biggest bears (Polar) and penguins ( Emperor) are found at the poles.

Small mammals and birds lose their heat very rapidly, so need a high metabolic rate in order to keep generating heat. Thus large mammals can feed once every few days whilst small mammals must feed constantly.

Question 3

Metabolic Rates and SA:V

Answer 3

Smallerorganisms, such as a mouse, have greatermetabolic ratesthan larger organisms, likeelephants. This is due to the mouse’s high surface area to volume ratio. The mouse must eat more than the elephant to maintain its body temperature.

Question 4

Alveoli and Ficks Law

Answer 4

Short diffusion distance - 1 cell thick
Concentration gradient - Continous blood flow maintains gradient
Large SA - A lot of alveoli

Question 5

Answer 5