Logged out
Access All our Essays in an Instant
Swap your work for FREE access, or pay £4.99 for instant access
Describe how size of living organisms determines the process, structure and function of gas exchange system.
Member rating:
(1 vote)
| Words:
| Submitted: Thu Sep 18 2003
Page Preview
On the left is an image preview of every page of this document, and below are the first 150 words with formatting removed:
Describe how size of living organisms determines the process, structure and function of gas exchange system Organisms rely on diffusion to fulfil their physiological needs. Over time different organisms have adapted so that they can meet their own demands. This is particularly evident in the way gaseous exchange relates to the size of the organism. The organism's oxygen requirements are proportional to its volume i.e. the bulk of the respiring tissue it contains. The exchanges are proportional to the surface area over which diffusion of oxygen can take place. The mathematical rule is - as an object increases in volume the ratio of its total surface area to voulme decreases i.e. The larger the object the smaller it's surface : volume ratio. In small organisms such as protozoa (Amoeba- around 1mm in diameter) the surface : volume ratio is sufficiently large for diffusion over its general body surface to satisfy it's respiratory needs (diffusion...
To see the full version of this document, and 145,348 others
