Marshall D. Sahlins, Evolution And Culture
One common notion of progress can be dismissed out of hand. Most of us have a tendency to equate progress with efficiency, which is not altogether surprising because this idea is peculiarly appropriate to a competitive, free-enterprise economy. But an organism’s thermodynamic efficiency is not a measure of its general evolutionary status. By efficiency we usually mean some ratio of output to input; thus in rating a machine’s efficiency we divide the output of work by the input of energy.
Analogously, a measure of the thermodynamic efficiency of a living thing would be the amount of energy captured and used relative to the organism’s own expenditure in the process of taking it. But suppose we know the efficiency of an organism as an energy-capturing machine; the use to which the efficiency is put remains unknown. Is it put into build-up of higher structures or into more numerous offspring, each of which concentrates a relatively low amount of energy. The implication is inescapable: an organism can be more efficient than another and yet remain less highly developed.