32 ENVIRONMENTAL RELATIONS 



are the center about which all other activities of the organism rotate, 

 and the breeding-place is the axis of the environmental relations of the 

 organism (6, 48, 49, 50). Migratory birds are our most striking motile 

 forms. They may migrate great distances, but always come back to the 

 same kind of area to breed. 



Failure to recognize the relative importance of the different activities 

 is in part responsible for the general unorganized state of our knowledge 

 of natural history. Investigators have often failed to interpret the 

 relations of animals to their environments because they have regarded 

 the records of the occurrence of all stages of the life history as equally 

 important. They have considered the occurrence of the most motile 

 stage in the life history as significant, for example the occurrence of an 

 adult butterfly. Plant ecologists would have met with equal success if 

 they had studied only the environmental relations and distribution of 

 wind-disseminated seeds. 



We have noted reasons for not putting primary emphasis on structure 

 and form as a basis for the organization of ecology. The above discus- 

 sion shows that activities are actually most important, and accordingly 

 may be used in ecological study. However, since structure and activity 

 (function) are always correlated, we should never lose sight of the former. 



IV. SCOPE AND MEANING OF ECOLOGY 



I. SPECIES AND ECOLOGY 



In practice, species are diagnosed in terms of structures, such as 

 number and arrangement of bristles, hair, form, color, size, etc. Such 

 characters are commonly called morphological. In ecology, the morpho- 

 logical characters of species are of little or no significance. Still, since 

 habitat preferences are commonly closely correlated with the characters 

 used to separate species, some progress in ecology can be made by the 

 study of the distribution and environmental relations of species, but if 

 this is not carefully checked by experimentation one may constantly 

 fall into error. 



2. MORES PHYSIOLOGY THE BASIS OF ECOLOGY 



As we have already seen, ecology 1 is that branch of general physiology 

 which deals with the organism as a whole, with its general life processes as 



1 The unorganized phases of ecology are sometimes called natural history, biology, 

 ethology, or bionomics, but usually by men having little understanding of plant ecology 

 or who for some reason object to the word ecology (see 350, pp. 18-21). The term 

 ecology is applied to those phases of natural history and physiology which are organ- 

 ized or are organizable into a science, but does not include all the unorganizable data 



