In this video we look at the idea of surface area to volume ratio. First we explore how unicellular organisms can rely on diffusion through their cell membrane for transferring molecules in and out of the cell. We then look at what is meant by the surface area to volume ratio. I show you how to calculate the surface area to volume ratio and give you an example to try yourself. Finally, we look at how multicellular organisms have evolved to exchange substances.

This video is aimed at the UK A Level Biology specifications. Students studying International A Level Biology will need to check their specification.

Image Credits:

Amoeba
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SmallRex, CC BYSA 4.0 https://creativecommons.org/licenses/..., via Wikimedia Commons

Flatworm
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Betty Wills, CC BYSA 4.0 https://creativecommons.org/licenses/..., via Wikimedia Commons

Cod
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Photo: HansPetter Fjeld, CC BYSA 2.5 https://creativecommons.org/licenses/..., via Wikimedia Commons