SCOPE AND SIGNIFICANCE 3 



biology into botany and zoology, its rapid development should not 

 now be hindered by renewed division and philosophical analysis. 



Nature. Ecology is in large measure the science of community 

 populations. It is concerned with natural communities primarily, and 

 has developed a considerable fund of organized knowledge of plant 

 communities and their dynamics, and a lesser body of similar knowl- 

 edge on the animal side. Because of the synthesis inherent in it, 

 ecology is also to be regarded as a point of view and a method of 

 attack for various great biological problems. Not only does it concern 

 itself more or less with the whole of biology, but also it must borrow 

 largely from chemistry and physics, from climatology, geology, and 

 soil science, and at the same time make basic contributions to the 

 practical sciences of agronomy, horticulture, forestry, grazing, entomol- 

 ogy, conservation, etc., to say nothing of education, economics, sociol- 

 ogy, and politics. It cannot, and does not, venture to draw a line 

 between the past and the present, and it has as significant a role to 

 play in geological as in modern times. 



More than a quarter of a century ago, the statement w^as made 

 that ecology was to be considered the central and vital part of botany, 

 and this is equally true for biology. It was further stated that plant 

 ecology is physiology carried into the actual habitat, and in conse- 

 quence its paramount theme is stimulus and response. It confines 

 itself primarily and exhaustively with the cause-and-effect relation 

 between the habitat on the one hand, and the organism and the com- 

 munity on the other. All further relations arise out of this, and all 

 other approaches are incomplete unless they lead back to it. With 

 the inclusion of animals in the biotic formation (biome), this rela- 

 tion naturally becomes more complex, but it is none the less valid. 

 Since physiology often finds visible expression in behavior, coaction 

 between the organisms assumes a role often more important than 

 direct response to the habitat. 



From this springs the view that development is the basic process 

 of ecology, as applicable to the habitat and community as to the 

 individual and species (Clements, 1904, 1905). It recognizes that life 

 constitutes a dynamic system and that static studies are valuable only 

 as they throw light on development or serve some practical purpose 

 in this connection. Furthermore, it was postulated that development 

 is a cyclic process and that the apparent jioints of rest in it are rela- 

 tive to cycles of different rank. At the very outset it was clearly per- 

 ceived that a dynamic system renders measurement indispensable, and 

 hence the past three decades have seen a consistent advance in this 

 respect, especially in plant ecology and to some extent in hydrobiology. 



