318 ECOLOGY 
referred. Our methods may not, at present, be sufficiently delicate to 
detect such structure, or the processes which lie back of it, but we may, 
it is believed, confidently expect the necessary methods for the detection 
of such structures and processes, and especially their correlation with and 
relation to the more permanent and more easily recognizable morpho- 
logical conditions. 
We classify the responses and changes in animals as evolution, 
modification by the environment, behavior, and physiological response. 
Are not all these, after all, but different expressions of the same or 
similar processes? Future investigations must answer this question, 
and it is around this question that the future of much that is known as 
biology hinges. 
VII. Retations oF EcoLtocy to GEOGRAPHY 
Ecology is primarily the study of the mores of animals and animal 
communities. It is fundamentally a branch of physiology—the physi- 
ology of the relations of animals to their environments. While we may 
study in the field and in the laboratory, both types of study are commonly 
conducted with reference to natural environments. Natural environ- 
ments are used as the basis for study, because when natural environments 
are destroyed, animals which can live in the new conditions select some 
one of several possibilities which approach the normal habitat. Habits 
appear particularly variable under these conditions. Little can be 
gained from the study of the relations of animals to man-made environ- 
ments, except in cases where the species has long been living under 
such conditions and has become fully adjusted to them. 
Ecology being a subject or branch of physiology, and including 
all of the sociological side of animal life, its relations to human geography 
are particularly intimate. Indeed, geographers have been disappointed 
with the data which zodlogy has furnished them, as these data are 
almost exclusively data concerning the taxonomy and morphology of 
animals. The parallelism between the geographic phenomena in animals 
and the “relation of culture to environment”’ lie not in the color and 
structural adaptations of animals, but in the behavior-characters of 
animals which enable them to live under a given set of conditions, and 
the behavior which those conditions produce (207, 208, 209). 
While attempting to make comparisons between human society 
and man on the one hand, and plants and animals on the other, geog- 
raphers, sociologists, and psychologists—in so far as I have been able 
to read their writings along this line—have compared structure in plants 
