CIE A Level Biology复习笔记4.2.7 Surface Area to Volume Ratios

• Surface area and volume are both very important factors in the exchange of materials in organisms
• The surface area refers to the total area of the organism that is exposed to the external environment
• The volume refers to the total internal volume of the organism (total amount of space inside the organism)
• As the surface area and volume of an organism increase (and therefore the overall ‘size’ of the organism increases), the surface area : volume ratio decreases
• This is because volume increases much more rapidly than surface area as size increases

As size increases, the surface area : volume ratio decreases

The surface area:volume ratio calculation differs for different shapes (these shapes can reflect different cells or organisms)