HUMAN ECOLOGY
Ecology in its most inclusive sense is the study of the relationship of organisms or groups of organisms to their environment. It perceives all life as a system of relationships that has been called the "web of life," of which every species forms a part. Human ecology is a branch of general ecology. It holds the view that humans, like all other organisms, are related to each other on the basis of a "struggle for existence" in an environment with finite limitations for supporting life. Struggle includes all activity (whether in competition, conflict, or cooperation) to survive and reproduce within these constraints.
Like every other species, humans must find a niche in their largely self-constructed web of life in order to gain a livelihood. In doing so they must make use of the resources and submit to the constraints imposed by the environment in which they find themselves. Unlike classical economics, which tends to view this process as one of individual adaptation, human ecologists insist on adaptation as a group: a collective phenomenon in which the main players are households, families, neighborhoods, and communities.
Environment
The environment is a sweeping concept that is defined to include all forces and factors external to an organism or group of organisms. The organism is responsive to the environmental conditions that are relevant to its needs and makes use of its existing technology. However, since the environment exists independently of any individual or species, it has no propensity to favor the needs of one organism or group of organisms (including humans) in preference to others. Consequently, in the short run humans must adapt to the conditions of the existing environment. In the long run they may modify ("build") the environment in ways that make life more secure and enjoyable. This too is a type of adaptation.
Because humans have genetic mental and physical capabilities for adaptation that far exceed those of any other animal, they are able to devise tools to assist in the exploitation of the environment in their struggle for survival. Furthermore, they have an unmatched ability to store past experience in memory and in a variety of records and possess a constructive imagination to guide their adaptive efforts. The magnitude of these differences from other animals is so great that it becomes the basis for a separate discipline of human ecology.
The exposition of human ecology as a distinct social science discipline is closely linked with the work of the sociologists Amos Hawley (b. 1910) and Otis Dudley Duncan (b. 1921).
All branches of ecology concur that adaptation is a group rather than an individual struggle. Membership in a compatible group is a condition of survival. Human ecology not only subscribes to this view but makes it a basic principle. In this view populations that occupy a particular sector of the environment (a habitat) adapt by organizing territorially delimited human communities. This is accomplished through the use of tools and technologies that derive from human ingenuity and cumulatively learned capabilities. The relationship of a population to its habitat is generally conceived as one of balance between human numbers and the opportunities for living.
Classical ecology sees three or four variable factors involved in the process of adjustment to the environment. Hawley postulates three: (1) population size, (2) the material or resource environment, and (3) the organization of the population. Within the third category Duncan distinguishes between social organization and technology to formulate the fourfold POET acronym of the "ecological complex": Ecological adjustment is a function of population, organization, environment, and technology.
Because demography is the study of population, there is much overlap in subject matter and research between human ecology and demography. Demography tends to be concerned with the renewal processes of large human population aggregates such as nation-states. Human ecology tends to focus on the detailed socioeconomic composition of population and its distribution over environments. It is an eclectic or "holistic" discipline that borrows freely from the theories and empirical research of such disciplines as sociology, evolutionary biology, economics, geography, demography, political science, and the physical sciences, integrating them with its own distinctive viewpoint. Some have characterized this viewpoint as social Darwinian.
Spatial Aspects of Ecological Organization
An important activity of all studies of ecology, particularly human ecology, is the portrayal by means of maps, graphs, and statistics of the distributions and densities of population in space. Mistakenly, some have defined human ecology solely or primarily as the descriptive study of spatial variations and patterns. However, the use of mapping and spatial analysis in studies of human ecology is guided by the more profound desire to understand ecological organization, interaction, and environmental adaptation. Ecology posits three basic factors to explain spatial patterning:
- Interdependence among persons. People who depend on one another daily must be closer together than are those who exchange services less frequently.
- Dependence on the physical environment. To gain its livelihood, a community must have access to raw materials, water, agricultural products, and other essential goods. In primitive situations this dependence is on the local habitat, and in more advanced societies it involves a wider sphere, via adjoining communities and particular ones located far away.
- Friction of space. Technology facilitates the movement of goods, people, services, information, and money over substantial distances. Travel and transport of materials and persons from their place of origin to a desired destination require both time and energy, imposing "frictional" costs. The efficiency of transportation and communication measures this friction. Time and transport costs become important factors in determining the location of all types of firms and organization and also of private residence. Reduction in friction permits their wider scatter.
Urban, Rural, and Metropolitan Ecology
As commerce and industry develop, the larger centers (towns) become more dominant over settlements in the surrounding territory, and people travel there to exchange products and services. Such "central places" developed along convenient transportation points: rivers, seashores, or areas where favorable resources existed, at the intersection of routes (breaks in transportation). With advancing technology and population growth, the number of such dominant cities (to which the term metropolis is commonly applied) has multiplied manyfold. Moreover, as central places expand, they tend to spill over their legal boundaries into the adjacent territory, giving rise to increasingly diverse outlying satellite urban places and residential areas collectively known as suburbs or metropolitan rings.
Each city center interacts continuously with an extensive territory beyond its legal boundaries. The territory over which a particular center exercises dominance through a geographic division of labor is its hinterland. The intensity of interaction between the center and a point in the hinterland diminishes with distance from the center. The total community area may be divided into a primary area (daily commuting, retail shopping, intense interaction) and a secondary area of lesser dominance where many services are performed by local (subdominant) centers. The term metropolitan area (central city and its suburbs) is assigned to the former, and the term metropolitan hinterland to the latter. The outer boundary to this hinterland cannot be defined precisely; it is a zone within which the sphere of influence of one center is counterbalanced by the competing influence of an adjoining center, which varies for each of a wide range of indicators.
Under conditions of advanced technology manufacturing enterprises have considerable freedom in choosing a location. Location near the central business district may be unimportant for such an enterprise, particularly if its product is distributed nationwide or internationally. In contrast, retail and personal service enterprises are population-sensitive: They must locate near the sites where the people who consume their products and services live or work. More specialized units of this class, such as department stores, and stores selling narrower ranges of goods (jewelry, musical instruments, expensive clothing), as well as firms providing specialized financial, legal, or other professional services, seek a highly accessible location such as the city center or large outlying shopping centers. Single-purpose units such as filling stations, grocery stores, drugstores, laundries and dry cleaners, restaurants, churches, schools, and health facilities tend to settle in the neighborhoods to provide their clients with easy access.
Some very large metropolitan areas are renowned for serving a worldwide clientele, dominating other metropolitan centers. Familiar examples are New York, London, Paris, and Tokyo. Other large cities may be dominant within a nation or region. Still other metropolitan places may serve much smaller regional areas but provide linkages to the broader national and international network.
Although in industrialized countries a disproportionate share of the population may live in metropolitan areas and suburbs, by far the larger share of the physical environment consists of sparsely settled nonmetropolitan and rural areas. Some human ecologists cover all such categories; others tend to specialize, being primarily urban, suburban, or rural in their focus.
Ecological Change
A universal ecological process is temporal change, an irreversible alteration of an existing pattern of ecological relationships. Although most ecological processes tend to produce equilibrium and balance between interacting organizations and groups, change in ecological organization (whether as a result of small cumulative increments or sudden and drastic "shocks") is ever present. Change may come from alterations in population, the environment, technology, or social organization.
The principal mechanism of ecological change is nonrecurring spatial mobility. Recurrent mobility–habitual routine round-trip movements–produces little change. In fact, it promotes stability and equilibrium. One-way journeys (migration) signal ecological change. By studying the causes of migration, ecologists seek to study both the underlying causes and the resulting adjustment that occurs. It is important to know not only why migrants think they have moved but also the environmental conditions or characteristics that are present in cases where migration occurs and are lacking in cases where migration is absent or rare. The causes of migration may be categorized as "push" and "pull" factors: in their simplest forms, an excess of numbers in the area of origin and underpopulation in the area of destination.
The problem of overpopulation has long been a central concern of human ecologists. It exists in places where the number of persons in a given habitat is perceived to be excessive in relation to the opportunities for life and livelihood. Overpopulation may come about through sustained rapid population increase. However, it can also result from a temporary or long-term reduction in the food supply, the exhaustion of a natural resource, or the closing of a major local source of employment.
Some of these symptoms seem to be manifest in a substantial share of the world's living spaces, caused at least partially by the nature of global economic organization and regional disparities in fertility and population growth. Migration is technically a solution to overpopulation but raises other problems: It may be seen as threatening population balance in areas where a high level of prosperity has been achieved. Overpopulation may diminish as the conditions that generate it are corrected. A new phenomenon–underpopulation, or failure to maintain replacement–is also of interest to students of human ecology. Explaining this phenomenon, as for many other topics of human ecology, requires study of collectively held beliefs, opinions, and expectations.
Human Ecology and Collective Beliefs
In its classical formulation human ecology strongly discounted the influence of individual psychological phenomena on group behavior. More recently, there has been agreement that collective beliefs–beliefs shared by a large segment of a group–may underlie ecological changes that cannot be satisfactorily explained by environmental, organizational, or technological factors alone. Dominant beliefs about religion, economic organization (capitalist, collective), and status (class) exclusiveness as well as racial-ethnic preferences and antagonisms are examples.
BIBLIOGRAPHY
Anderton, Douglas L., Richard E. Barrett, and Donald J. Bogue, eds. 1997. The Population of the United States. New York: Free Press.
Blau, Peter M., and Otis D. Duncan. 1978. American Occupational Structure. New York: Free Press.
Bogue, Donald J., and Elizabeth J. Bogue, eds. 1976. Essays in Human Ecology. Chicago, IL: Community and Family Study Center, University of Chicago.
Duncan, Otis D. 1983. Metropolis and Region. New York: AMS Press.
Duncan, Otis D., Howard Schuman, and Beverly Duncan. 1973. Societal Change in a Metropolitan Community. New York: Russell Sage Foundation.
Hawley, Amos H. 1950. Human Ecology: A Theory of Community Structure. New York: Ronald Press.
——. 1979. Societal Growth: Processes and Implications. New York: Free Press.
——. 1986. Human Ecology: A Theoretical Essay. Chicago, IL: University of Chicago Press.
