142 HUMAN BIOLOGY 



which are great heterotypic associations of numerous animals 

 and plants occupying the same type of environment and 

 entering into the most diverse and intricate relations with 

 one another, e.g. the biota (fauna and flora) of a tropical 

 rainforest regarded as a whole, that of a bog, sand dune, 

 desert, lake, etc. In all these cases the associations are more 

 or less unstable and temporary, because not very highly 

 integrated. Their integration, in fact, seems to be largely 

 determined by general, extrinsic or environmental stimuli. 



The societies, as distinguished from the associations, 

 are more permanent, organized wholes which depend 

 primarily on the behavior of the component individuals 

 towards one another. In order to be with its fellows the 

 social individual will not infrequently seek to adjust itself 

 even to a harmful or fatal environment or situation. Hence 

 societies, as a rule, can be established only between indi- 

 viduals of the same species, i.e. of the same genetic origin, 

 but there are exceptions in which individuals of two or 

 more species may form single societies (ants, bees, wasps, 

 compound flocks and herds of birds and mammals). We may 

 therefore distinguish homotypic and heterotypic societies. 

 Human societies are in many ways so peculiar that they 

 may be assigned to a third category by themselves. 



Now it is obvious that all associations and societies 

 are merely peculiar expressions of the most general and 

 fundamental activities of living things, namely adaptation, 

 and it is also apparent that the associative and social 

 adaptations are referable to the basic physiological responses 

 of the individual organisms to stimuli emanating from their 

 fellows or their general environment. We may roughly 

 divide these responses into three general categories, those 

 which satisfy the nutritive, reproductive and protective 

 (defensive and offensive) needs of the individual organism, 

 respectively. The different societies may therefore be classi- 

 fied according to the preponderance of these several needs, 

 in their behavior. Thus such societies as the human person, 

 which consists of some 60,000,000,000,000 cells and such 

 compound organisms as the Portuguese man-of-war, tape- 

 worm, etc. are of the predominant nutritive type. All 

 their individuals are in contact or interconnected in such 



