THE ENERGETICS OF ORGANISMS 95 



Proteins, fats and CO 2 + OH 2 + nitrogenous 



carbohydrate give rise to residues + available energy, 



being oxidized 



The available energy is mainly expended in the muscular motions 

 of circulation of bodily fluids, respiration, etc., and of the muscular 

 motions of the body and its members during the activities of 

 behaviour. In these activities available energy dissipates. In 

 general the activities of the fully-grown, non-reproductive typical 

 animal are kataholic ones. 



36^. Anabolic Processes in Animals. But when the 

 animal is growing its foodstuffs are not merely oxidized, and so 

 degraded, but are built up into new bodily tissues. And when 

 it is reproducing the materials of the foodstuffs are converted 

 also into the substances of eggs and spermatozoa, or (if it is a 

 pregnant or nursing parent) into the materials of the embryonic 

 tissues. So the processes are anabolic ones, to that extent. 



In a plant population the tissues of the bodies may accumulate 

 as vegetable debris, etc. (see above). But in an animal population 

 there is no accumulation of the substances of the bodies, for 

 when the latter die their tissues are resolved into CO 2, 

 OH 2, inorganic nitrogenous salts, etc. — materials in which the 

 energies have been dissipated. Therefore the general result of 

 animal metabolism is to lead to energy-dissipation — or entropy- 

 increase. 



36^. The Effects of Behaviour. The energetic effects of 

 animal behaviour are indeterminate. Thus all the activities of 

 a community of men might be given over to war and its prepara- 

 tion — in that case the energy of the population would simply 

 be dissipated, in the energetic sense. Or the population might 

 be a pastoral-agricultural one, in which case it might raise crops 

 and cattle and so largely increase the quantities of available 

 energy — and retard entropy-increase. And so with other 

 animals. 



In general the results of animal activity are to accelerate the 

 dissipation of energy, that is to accelerate entropy-increase. 



36c. The Animal Engine. In the heat engine (steam, gas, 

 petrol) the kinetic energy comes from the oxidation of the fuel, 

 which burns to CO 2 and OH 2. This is not directly the case 

 with the animal engine, where part of the potential energy of 



