COMMUNITY ORGANIZATION: STRATIFICATION 



441 



in the struggle for nourishment and other 

 interrelations. Their protoplasmic nature is 

 obvious, but the complete interdependence 

 of organisms and their arrangement into or- 

 ganized communities for survival is only 

 now becoming realized. This reaUzation 

 suggests an extracellular extension of the 

 Cell Doctrine (Table 30). 



Exceptions are known to all three doc- 

 trines noted in this table; these few excep- 

 tions may be real, or are consequences of 

 incomplete information or of incomplete 

 synthesis. In these doctrines the organism 

 is the essential connecting link; it is the 

 hinge on which both cells and communi- 

 ties depend for continued existence. In the 

 same way, organismal survival is depend- 

 ent on cells for assimilation, and communi- 

 ties for food supply. 



Study of the organism, therefore, belongs 

 to all biologists. Study of its parts embraces 

 anatomy and physiology, its inherited fea- 

 tures occupy the geneticists, its environ- 

 mental adjustment is the realm of autecol- 

 ogy, its classification with relation to other 

 organisms is a concern of taxonomy, and 

 its association with other organisms be- 

 comes the study of synecology. This last 

 phase has been slower to receive biological 

 support, since, because of its innate com- 

 plexity and its dependence on synthesis of 

 many aspects of biology as well as analysis, 

 it has appeared as a point of view more 

 often than as an organized field of study. 

 An example of a critical attitude toward 



synecology is that of Uvarov (Riley, 1944). 

 Such criticism is to be expected until this 

 complexity can be thoroughly analyzed and 

 the biological necessity of the community— 

 i.e., the counterdependence of the organism 

 on its community— is more generally appre- 

 ciated. Both the organism and the commu- 

 nity change through time; this is implied in 

 the doctrines just stated. In organismal evo- 

 lution there are some documentary data to 

 show that the evolved product is the func- 

 tion of genetic changes of the germ plasm, 

 operating through the soma, and selected 

 by the enviionment. Modern ecology has 

 a definite contribution to make in the study 

 of organismal evolution, which will form 

 the basis for a later section. The evolution 

 of communities, or succession, is an espe- 

 cial phase of synecology and is considered 

 in the present section. 



The general structure, functions, and 

 evolution of major communities form three 

 points of departure from which synecologi- 

 cal principles may be examined. To some 

 extent this procedure limits the field of in- 

 quiry. Communitv classification (Warm- 

 ing, 1909; Shelf ord, 1913; Pearse, 1939) 

 and the detailed examination of a single 

 community (Carpenter, 1940a) or detailed 

 examination of certain phases of synecology 

 (Clements and Shelf ord, 1939) recently 

 have been emphasized, and these several 

 bodies of information and theory will be 

 drawn upon extensively. 



26. COMMUNITY ORGANIZATION: STRATIFICATION 



The community usually has a characteristic 

 appearance. This general aspect is difficult 

 to describe briefly, but is easily apprehended 

 after sufficient field experience. Recogni- 

 tion in the field depends upon the rapid 

 integration of numerous criteria, the sum- 

 mation of which presents the observer with 

 a mental image of a particular community 

 type. Such a typical aspect or habitus im- 

 plies a general ecological demand by the 

 community that is the net result of the 

 numerous demands of the contained con- 

 stituents. It is safe to conclude that as 

 familiarity with species taxonomy and 

 ecology increases, there is a gain in finer 

 perception of community habitus. As the 

 total taxonomic composition of any two 



communities, or related series of communi- 

 ties, approaches similarity, the total ecolog- 

 ical requirements of such assemblages be- 

 come more similar. Conversely, as the total 

 taxonomic dissimilarity increases, the eco- 

 logical requirements become progressively 

 dissimilar. 



Despite great differences in habitus, all 

 self-sustaining communities have certain 

 features of organization in common. Such 

 features are of prime importance, since 

 their nearly universal occurrence suggests 

 fundamental consequences innate in the 

 interdependence of taxonomically disparate 

 populations. Study of these common struc- 

 tural features forms the basis of commu- 

 nity morphology. This common structural 



