Maths for A Level Biology - updated edition

In addition, the bigger the organism, the less area it has per unit volume through which it loses heat. The smaller organism has more area for each unit of its volume through which it will lose heat, which is consistent with the observation that of closely related species, those found in Arctic environments are larger than those found in temperate environments. Polar bears are bigger than the European brown bear and arctic foxes are longer than red foxes, supporting this argument. Similarly, babies have a much bigger surface area : volume ratio than adults and so they lose heat much more quickly, which is why they are more at risk of hypothermia than adults. The table below shows how these ϐigures increase as the size of the cubic organism increases: Side length / units Area of each side Total surface area Volume Surface area : volume 1 1 6 1 6.0 : 1 2 4 24 8 3.0 : 1 3 9 54 27 2.0 : 1 4 16 96 64 1.5 : 1 5 25 150 125 1.2 : 1 6 36 216 216 1.0 : 1 7 49 294 343 0.9 : 1 8 64 384 512 0.8 : 1 9 81 486 729 0.7 : 1 10 100 600 1000 0.6 : 1 Now look at these three graphs: 1 Surface area and length of side 600 500 400 300 200 100 0 Length of side Total surface area 0 2 4 6 8 10 × × × × × × × × × × This graph shows that as the lengths of the sides increase, the surface area increases. The line is not straight. With longer sides, the area increases more and more. Pointer Think about what the numbers mean, in biological terms. 2 Processed numbers 37