HISTORICAL DEVELOPMENT OF THE CONCEPT 5 



From the standpoint of development, miiformity is inevitable and 

 universal, but it is a uniformity of i)roccss and cycle more than of 

 end results. This becomes all the more evident when it is realized that 

 cycles of varying intensity and duration are so telescoped that lesser 

 ones constantly recur within the next larger, producing a complex 

 system in which the respective cycles are difficult to discover. jNIore- 

 over, while cycles in deformation, climate, physiography, soil, climax, 

 migration, and abundance bear an organic relation to one another, 

 response takes place at varying rate and degree, and the mosaic of 

 jn'ocesses becomes correspondingly intricate. 



The principles and methods of paleo-ecology have been outlined 

 in more or less detail for vegetation (Clements, 1914, 1916, 1918; 

 Clements and Chaney, 1925-35, 1936), and these have been applied 

 to the revaluation of fossil floras with such success as to indicate their 

 fundamental nature (Chaney, 1925, 1933). As with modern ecology, 

 these must necessarily undergo certain extensions and modifications 

 v.-ith the adoption of the biome as the community. Furthermore, while 

 relatively slight changes are needed to fit the case of land climates 

 and climaxes, those of deep water exhibit conditions at once so differ- 

 ent and so uniform as to require much greater modification. 



As has been emphasized elsewhere (Clements, 1916) , it is an axiom 

 that the key to the past is fashioned by the present, to use these terms 

 in their everyday significance. On the other hand, the present is the 

 sole heir to the past, and no adequate understanding of it is possible 

 without tracing the continuity of developmental processes from the 

 one to the other. In short, there is no more warrant, other than that 

 of convenience and emphasis, for separating paleo-ecology than for 

 dividing bio-ecology, and the best development of ecology demands 

 the synthetic organization of the entire field, even though detailed 

 analyses will continue to be made by specialists. 



HISTORICAL DEVELOPMENT OF THE CONCEPT 



The idea of the plant community in general extends backward 

 for nearly two centuries, but the recognition of the biotic community 

 is a recent matter. Post (1867) recognized that the organic world 

 should be dealt with in its entirety, but seems to have had no definite 

 idea of the community as a unit (cf. P. Palmgren, 1928:27). How 

 clearly Mobius perceived the existence of a biotic connnunity can 

 probably never be settled, in spite of his introduction of the term 

 biocenose. He certainly saw something of a community relation in 

 the oyster assemblage (1877), but carried the concept no further, and 



