Surface Area to Volume Ratio Flashcards
1
Q
Surface area formula
A
length x width x number of faces
2
Q
Volume formula
A
length x width x height
3
Q
How are substances exchanged in single-celled organisms?
A
Substances diffuse directly into cell across cell-surface membrane
4
Q
Why does diffusion through cell-surface membrane not occur in multicellular organisms?
A
- Some cells too deep in the body (diffusion distance to long)
- Larger organisms have a small SA:V
5
Q
How are substances exchanged in multicellular organisms?
A
- Specialised exchange systems
- Mass transport (carrying substances to and from cells)
6
Q
What does rate of heat loss from an organism depend on?
A
Surface area (body size and shape)
7
Q
Examples of other adaptions to aid exchange
A
- Animals with large SA:V tend to loose more water via evaporation, so small desert animals have adapted kidneys to produce less urine
- Small animals have high metabolic rates, so small animals in cold regions have thick fur and eat many calories
