Gas Exchange

ADAPTIONS

Most gas exchange surfaces have two common areas:

-They have a large surface area
-They're one cell thick, therefore have a short diffusion pathway.
-Organisms maintain a steep concentration gradient across the exchange surface.

These three factors all increase the rate of diffusion.

SINGLE CELL ORGANISMS

Single cell organisms absorb and release gases through diffusion through their outer surface. They have a relative short diffusion pathway due to a large surface area and thin surface so they have no need for a gas exchange system.

GAS EXCHANGE IN FISH

Due to a lower concentration of oxygen in water, fish had a need to adapt to their conditions.

-Water enters through the mouth and out through the gills of the fish.
…