Exchange Surfaces Flashcards
How easily stuff moves between an organism and its environment depends on what?
Its surface area to volume ratio.
In single celled organisms how can gases and dissolved substances diffuse into or out of the cell across the cell membrane?
Because they have a large surface area compared to their volume so enough substances can be exchanged across the membrane to supply the volume of the cell.
What happens when multicellular organisms have a smaller surface area compared to their volume?
Not enough substances can diffuse from their outside surface to supply their entire volume.
How are exchange surfaces adapted to maximise effectiveness?
Thin membrane - substances only have a short distance to diffuse
Large Surface Area - lots of a substance can diffuse at once
In animals with lots of blood vessels - to get stuff in and out of the blood quickly
Ventilated
