As organisms increase in size they have to develop strategies to enable adequate gas exchange to occur. Explain why this is and how organisms overcome this problem.

Authors Avatar
As organisms increase in size they have to develop strategies to enable adequate gas exchange to occur. Explain why this is and how organisms overcome this problem.

(WRITE ABOUT S.A. : VOLUME RATIO GETTING SMALLER ETC.)

When the volume of a gas exchange surface increases, the diffusional distance for the oxygen also increases. This causes problems because when the diffusional distance reaches a certain point, gas exchange stops being efficient and new and more efficient strategies for gas exchange are needed. Often, diffusion through the skin is not a satisfactory method of gas exchange because the skin is designed to protect the body, therefore it is a non permeable suface. Certain organisms have been adapted to cope with this problem. They have formed specific methods and organs to aid their gas exchange.
Join now!


In flatworms, their shape provides a good surface for gas exchange. Their long, thin bodies create a large surface area but because of their narrow bodies, they have a small diffusional distance. Because flatworms are relatively small organisms, this strategy is sufficient for the level of gas exchange that is needed for them to live healthily. (GIVE FIGURES AND OTHER EG'S) Some organisms, such as plants, have a hollow centre. This means that there is no need for gases to be transported there because there is no metabolic tissue in the centre. Again, this lowers the diffusional distance ...

This is a preview of the whole essay