CHAPTER III THE ECOLOGICAL APPROACH TO THE STUDY OF THE HUMAN COMMUNITY The young sciences of plant and animal ecology have become fairly well established. Their respective fields are apparently quite well defined, and a set of concepts for analysis is becoming rather generally accepted. The subject of human ecology, however, is still practically an unsurveyed field, that is, so far as a systematic and scientific approach is concerned. To be sure, hosts of studies have been made which touch the field of human ecology in one or another of its varied aspects, but there has developed no science of human ecology which is comparable in precision of observation or in method of analysis with the recent sciences of plant and animal ecology. I. THE RELATION OF HUMAN ECOLOGY TO PLANT AND ANIMAL ECOLOGY Ecology has been defined as “that phase of biology that considers plants and animals as they exist in nature, and studies their interdependence, and the relation of each kind and individual to its environment.”[31] This definition is not sufficiently comprehensive to include all the elements that logically fall within the range of human ecology. In the absence of any precedent let us tentatively define human ecology as a study of the spatial and temporal[32] relations of human beings as affected by the selective, distributive, and accommodative forces of the environment. Human ecology is fundamentally interested in the effect of _position_,[33] in both time and space, upon human institutions and human behavior. “Society is made up of individuals spatially separated, territorially distributed, and capable of independent locomotion.”[34] These spatial relationships of human beings are the products of competition and selection, and are continuously in process of change as new factors enter to disturb the competitive relations or to facilitate mobility. Human institutions and human nature itself become accommodated to certain spatial relationships of human beings. As these spatial relationships change, the physical basis of social relations is altered, thereby producing social and political problems. A great deal has been written about the biological, economic, and social aspects of competition and selection, but little attention has been given to the distributive and spatial aspects of these processes. The plant ecologist is aware of the effect of the struggle for space, food, and light upon the nature of a plant formation, but the sociologist has failed to recognize that the same processes of competition and accommodation are at work determining the size and ecological organization of the human community.