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. ScorpE 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’ is that branch of general physiology 
which deals with the organism as a whole, with its general life processes as 
* 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 35a, 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 
