The range of body sizes is enormous. Prokaryotes span a huge cellular size range; the largest is the colourless sulphur bacterium Thiomargarita namibiensis with a cell volume of 2 × 10−10 m3, the smallest is Pelagibacter ubique at 10−20 m3. This small size has the remarkable implication that it has less than a single free proton in its cell if its internal pH is 7 as is typical for bacteria, see {430}. This has peculiar consequences for the molecular dynamics of metabolism. A typical bacterium with full physiological machinery has a volume of about 0.25 × 10−18 m3. The blue whale has a volume of up to 135 m3. A sequoia may even reach a volume of 2000 m3, but one can argue that it is not all living matter. Ironically, the organism with the largest linear dimensions is usually classified as a ‘micro-organism’: the fungus Armillaria bulbosa is reported to occupy at least 15 hectares and exceeds 10 Mg or 10 m3. The factor between the volumes of bacterium and whale is 5.4 × 1020, that between the volume a water molecule occupies in liquid water and that of a bacterium is ‘only’ 1010. The interdivision interval of a bacterium can be as short as 20 min; the life span of whales may exceed a century, while some plants live for several millennia.