Surface Area to Volume Ratio
- The greater the size of an organism, the smaller its surface area: volume ratio
- Larger organisms therefore require specialised exchange surfaces and transport mechanisms to meet their metabolic requirements
- Specalised exchange surface have: a large surface area, thin barriers and associated transport systems to maintain a steep diffusion gradient.
- Also, organisms with a higher metabolic rate require more nutrients and produce more waste, therefore require a specialised exchange surface