Ecology
Ecology
I. Human EcologyAmos H. Hawley
II. Cultural EcologyJulian H. Steward
I HUMAN ECOLOGY
The term “ecology,” which has its root in the Greek word oikos (household or living place), came into use in the latter part of the nineteenth century in the works of zoologists and botanists to describe the study of the ways in which organisms live in their environments. Soon two branches of ecology were distinguished: autecology, the study of the individual organism’s interaction with environment, and synecology, the study of the correlations between the organisms engaged with a given unit of environment. The latter study has prevailed, however, and has become the principal connotation of ecology, since it became evident in numerous field studies that organisms, whether plant or animal, establish viable relationships with environment, not independently but collectively, through the mechanism of a system of relationships. Bioecologists were thus led to employ a set of concepts and techniques of investigation that imparted a markedly sociological coloration to their work.
Origins and history
The ecological approach was introduced as human ecology into the field of sociology at a critical period in the development of the latter discipline. In the 1920s the reformistic phase of sociology was drawing to a close, and the subject was gaining acceptance as a respected discipline in the curricula of American universities. That the transition would have been effected so quickly without the aid of a theoretical framework lending itself to empirical research seems doubtful. Ecology opportunely provided the necessary theory. A period of vigorous research followed that was to prove instrumental in launching sociology on its career as a social science.
Sociologists made free use of analogy as they borrowed heavily from the concepts of plant and animal ecology. The Darwinian notion of animate nature as a web of life became at once a general orienting concept and a basic postulate; it directed attention to the necessary interdependence among men as well as among lower forms of life. A second concept, the balance of nature, denoting a tendency toward stabilization of the relative numbers of diverse organisms within the web of life and of their several claims on the environment, provided human ecology with its characteristic equilibrium position. The more or less balanced web of relationships, when viewed in a specific local area, presented the aspect of community, a concept with obvious appeal for students of human social life.
According to plant and animal ecologists, the community, or ecosystem, is a population comprising a set of species whose reactions to the habitat and coactions between each other constitute an integrated system having some degree of unit character. Coactions involve members behaving both with reference to their similarities in an mtraspecific relationship known as commensalism and with reference to their differences in what is called symbiosis, an interspecific relationship. The community develops from simple to more complex forms through a sequence of stages described as succession. Each stage in the sequence is marked by an invasion of a new species or association of species, the series culminating in a climax stage in which a dominant species appears. The dominant species is related to the environment in such a way that it is able to control and maintain the community indefinitely. The community, then, tends to approximate a self-maintaining, or “closed,” system.
Community and environment
The application of the concepts from plant and animal ecology to the human community carried with it the implication that the community was essentially a natural phenomenon, which meant that it had developed independently of plan or deliberation. From this it was a short, though uncritical, step to the interpretation of human ecology as a study of the biotic or subsocial aspect of human social organization (Park 1936), a view that was elaborated at some length by Quinn (1950). Not only did the subsocial characterization convey an excessively narrow concept of social organization, but it posed an operational problem for which there was no workable solution.
A somewhat different definition of human ecology, which ignored any reference to the cognitive level of events, was enunciated by McKenzie ([1924] 1925, pp. 63–64), whose formulation of the subject as a study of the spatial and temporal relations of human beings, affected by the selective, distributive, and accommodative forces of the environment, was widely accepted as authoritative. Although McKenzie’s definition inspired a large amount of fruitful research effort, it had the unfortunate effect of concentrating attention almost exclusively on spatial distributions and correlations. In consequence, many promising implications of ecological assumptions were neglected.
Hawley, in attempting to restore a conceptual continuity with plant and animal ecologies, advanced the view of human ecology as the study of the form and development of the human community (1950, p. 68). Community, in this connection, is construed as a territorially localized system of relationships among functionally differentiated parts; human ecology, then, is concerned with the general problem of organization conceived as an attribute of a population—a point of view that has been shown to be consistent with a long-standing sociological tradition (Schnore 1958). Although the emphasis is centered on the functional system that develops in a population, it is not intended to exclude concern with spatial and temporal aspects; rather, these aspects are regarded as useful dimensions for the measurement of organization.
A further step in making the orientation of human ecology explicit within the larger context of general ecological theory was made by Duncan (1959, pp. 683–684), who described four principal variables of human ecology—population, organization, environment, and technology—that constitute an ecosystem. In other words, while any one of the four may be treated as a dependent variable for certain purposes, it is also reciprocally connected with each of the other variables. The virtue of this perspective lies in the range of problems it opens to the student of human ecology. Yet it seems unlikely tin various eco-logical studies, although hat that advantage can be fully enjoyed without a clear notion of how organization is constituted.
Other applications
While sociologists were at work defining human ecology for their purposes and pursuing many of its research leads, the concept spread into various other fields of inquiry. Human geographers wondered if the term “human ecology” was not a more apt characterization of their discipline; but their historic preoccupation with the landscape and their general addiction to a macroscopic treatment of occupance led them to discard this notion. Archeologists, in their efforts to reconstruct population distributions, have made use of ecological concepts and techniques, but without attempting to give formal statement to the approach.
Studies of human evolution by anthropologists involved questions of the man-environment relationship, which, in turn, led them to describe their work as human ecology; indeed, social or cultural anthropologists have long engaged in various ecological studies, although not until recently have they so defined their activity. One definition by an anthropologist is that of Steward (1955), for whom human ecology is the study of the adaptation of specific items of culture to particular environments. This conception, which reduces ecology to something akin to a research technique, is shared by a number of Steward’s contemporaries.
The language of human ecology has also made its appearance in economics, psychology, epidemiology, and other fields. In some instances, the term is used merely as a label for an environmental emphasis; in others, it is put forward in an effort to broaden the purview of a discipline.
But in spite of the widespread diffusion of ecological concepts, responsibility for systematic development of human ecology has been left to sociologists, who have drawn heavily on related fields for both theoretical and technical aid. The writings on real estate, finance, public administration, demography, planning, history, and other areas of inquiry, in addition to the literature of the fields previously mentioned, have at one time or another been exploited in the interest of human ecology. The reason for that catholicity of taste is not hard to find; human ecology is concerned with sociological problems in their fullest breadth. It overlaps, therefore, all the spheres of learning that concern the social life of man.
Distinctive features of human ecology
As human ecology has moved toward a major concern with the general problem of social organization and thus closer to the central concern of sociology, it has retained certain distinctive features. Foremost among these is the importance attributed to environment.
The broad, positional hypothesis is that organization arises from the interaction of population and environment. Environment, however, defined as whatever is external to and potentially or actually influential on a phenomenon under investigation, has no fixed content and must be defined anew for each different object of investigation. Environment is seen both as presenting the problem of life and as providing the means for its resolution; to adopt this position is to place the problem in a time-space context.
A second distinguishing characteristic is the emphasis on population as the point of reference; organization, it is contended, is exclusively the property of a population taken as a whole and not of an assemblage of individuals. Obvious as this position may be, it has profound methodological and theoretical implications for the manner in which the ecological problem is put, the variables employed, and the data to be observed. The concreteness of population, however, in contrast with the seemingly ephemeral nature of organization, tends to beguile the student to a view of population as the independent variable in all things pertaining to organization. It is obviously more convenient to proceed from the more accessible to the less accessible by asking how a population makes a unitary response to its environment; yet that is merely a common-sense way of approaching the problem, and investigation soon makes it apparent that population is for many purposes better regarded as the dependent variable, delimited and regulated by organization.
A third characteristic is the treatment of organization as a more or less complete and self-sustaining whole. The interaction of population and environment is seen as culminating in a system of relationships between differentiated parts which gives the population unit character and enables it to maintain its identity. As the property of a population, organization lends itself most readily to a morphological, or structural, analysis. The parts are the units—individuals or clusters of individuals—that perform functions and the relationships by which these units are linked. Differing configurations of unit functions and relationships are expected to occur with differences in relationship to environment and at different stages in development.
A morphological concern does not exclude the problem of development. Presumably, any given form of organization had an earlier form and is capable of having a later form. Every organization has a history, perhaps a natural history, the knowledge of which may shed light on the nature of organizations by indicating, for example, at what points they are vulnerable to change and how change spreads through them.
Related to the conception of organization is a fourth distinctive, although by no means unique, attribute of human ecology: the central position given to an equilibrium assumption. Morphological change is assumed to be a movement toward an equilibrium state, whether through a succession-like sequence of stages or through a process of continuous modification. Unlike the equilibrium notion in some of its other applications, such as in functionalist theory, the ecological usage of the term harbors no teleological overtones; on the contrary, this usage merely implies that as an organization attains completeness, it acquires the capacity for controlling change and for retaining its form through time, although the interval need not be specified. To put it differently, to the extent that an organization possesses unit character, an approximation to equilibrium obtains.
There is a further implication that a stable relationship with environment is contingent on relative stability in the relationships between the parts of an organization. A population always remains open to environment, but the formation of organizations canalizes environmental influences and makes for increasing selectivity of response.
The term “community” has commonly been used to denote the unit of organization for ecological purposes. Operationally defined as that population which carries on its daily life through a given system of relationships, the community is regarded as the smallest microcosm in which all the parameters of society are to be found. For reasons that were largely fortuitous, human ecologists at first focused their attention on the city and its tributary area as the prototype of community; later, in an effort to encompass the antecedents of cities, they broadened their consideration to include all forms of nucleated settlement. The term “community,” however, has the disadvantage of referring to the organization of a more or less localized settlement unit that does not always approximate a self-maintaining whole. For example, in an extensively urbanized society, local settlement units are usually components of more inclusive systems; in that event, the entire system must be treated as the object of study. But the difference between a simple, compact organization and a large, diffuse one is primarily a difference in scale; accordingly, the principles of organization should be the same in each. Since the designation of both simple and complex systems as communities threatens confusion, a more neutral term, such as “social system,” is to be preferred.
Principles of ecological organization
Inasmuch as principles of organization hinge on what is meant by population, it is imperative that the concept be developed more fully.
A human population is an aggregate of individuals who possess the following characteristics. As a living organism, every individual must have access to environment, for that is the only possible source of sustenance. Moreover, the interdependence of individuals is necessary; this condition, which obtains for all forms of life, holds true to an exceptional degree in the case of man, because of the naked state in which he comes into the world and his long period of postnatal maturation. Interdependence is the irreducible connotation of sociality.
The human being also possesses an inherent tendency to preserve and expand his life to the maximum permitted by prevailing circumstances; this is a general motive of which all other motives are special cases. In its most elementary sense, expansion of life refers to the multiplication of man-years through either the leaving of progeny or the extension of longevity; but it also includes all that is involved in the realization of that objective. Another important characteristic is the indeterminacy of the human being’s capacity to adapt; there is no known restriction on the kind or extent of refinement of activity in which he can engage. Finally, the human individual, again like other organisms, is time-bound; the recurring needs for food and rest fix the fundamental rhythm of life and regulate the allocation of time to all other activities. Accordingly, the time available for movement is limited and, in consequence, the space over which activities can be distributed is correspondingly limited.
These several attributes of individuals not only define the kind of population with which human ecology deals, but they also constitute a cardinal set of assumptions from which principles of ecological organization may be deduced. The following are some of the more salient of these principles of organization.
Principle of interdependence
Interdependence develops between units on each of two axes: the symbiotic (on the basis of their complementary differences) and the commensal (on the basis of their supplementary similarities). That is, units that combine in a symbiotic union may also enter into other combinations of a commensal character; the effect of each type of union is to raise the power of action above what it would be were the units to remain apart.
The effect, however, is not the same in each case. The symbiotic union enhances the efficiency of production or creative effort; the commensal union, since its parts are homogeneous, can only react and is suited, therefore, only to protective or conservative actions. Although commensalism is an elemental form of union, it is applicable to a wide array of situations. The point of importance at present is that a population tends to be knit together through an interwoven set of symbiotic and commensal relationships.
It should be evident that interdependence has temporal and spatial implications for the units involved. Relations of functional complementation and supplementation require mutual accessibility among units; since this is contingent on the time available for movement, the distance separating related units is always subject to some limitation. In general, for every set of related units, there should be, other things being equal, an appropriate pattern of distribution in the temporal and spatial dimensions.
Principle of the key function
A second principle may be described as the principle of the key function. That is, in every system of relationships among diverse functions, the connection of the system to its environment is mediated primarily by one or a relatively small number of functions, the latter being known as the key function or functions. To the extent that the principle of the key function does not obtain, the system will be tenuous and incoherent; in the extreme case, in which no system exists, every function has the same relationship to environment. Given a functional system, then, there are always some functions or functional units directly involved with environment and others that secure access to the environment indirectly, through the agency of the key function.
The notion of key function invokes the question of how to define the notion of environment, which can refer to many different kinds of things. For present purposes, these things may be classified in two broad categories: the natural and the social. Although every organized aggregate must contend with both, the relative importance of each may vary over a wide range. In some instances, because of the inaccessibility of the settlement, activities of necessity center on the exploitation of the local natural environment, while influences from the social field are relatively infrequent or of no great consequence. In this event, the key function is the activity that extracts the principal sustenance supply from local resources. But where the product from local resources, or a substantial part of it, is exchanged for other sustenance materials, whether through trade or other distributive mechanisms, the key function is determined by the comparative importance of production and of trade as sources of sustenance.
In many such instances, no distinction is necessary because the producer is also the trader—two functions combined in one functionary. But even before the two functions appear as separate specialties, the requisites of trade or distribution begin to regulate the uses of local resources. As the reliance on exchange advances, the social environment actually displaces the natural environment as the critical set of influences. A population is never emancipated from its dependence on physical and animate matters, but the importance of locale declines with increasing involvement in a network of intersystem relations; the natural environment is extended and diffused, and contacts with it are mediated through a variety of social mechanisms. Hence, the functions that link the local system to the social environment come to occupy the key position.
Principle of differentiation
The extent of functional differentiation varies with the productivity of the key function or functions; this is the principle of differentiation. A corollary is that the size of population supportable by the system varies with the productivity of the key function. For given the simplifying assumption that each unit is fully occupied, the number of people is determined by the number of functions to be performed.
In a hunting and gathering community, for instance, productivity is usually low, even though the physical environment is richly endowed; hence, there is little time or opportunity available for the cultivation of more than a few specialized functions. Nor is it possible to support enough people to staff even a moderate extent of specialization. By contrast, where the key function is devoted to stable agriculture, the range of possibilities is much greater, while in an industrial system productivity is so great that there are no known upper limits on either the number of specializations or the size of the population that can be supported.
The productivity of the key function, then, constitutes the principal limiting condition on the extent to which a system can be elaborated, on the size of population that can be sustained in the system, and on the area or space the system can occupy.
A question of some importance has to do with the relative number of units engaged in each of several interrelated functions. That question remains unanswered at present. It may be suggested, however, that the number of units engaged in any given function is inversely proportional to the productivity of the function and directly proportional to the number of units that utilize the product of the function.
It follows, of course, that functional differentiation involves a differentiation of environmental requirements. As the materials and conditions used by diversely specialized units differ, so also will their needs for location in space and time. In general, units performing key functions have the highest priority of claim on location. Other units tend to distribute themselves about the key function units, their distances away corresponding to the number of degrees of removal separating their functions from direct relation with the key functions. The temporal spacing may be expected to reveal a similar pattern. Special location requirements, however, as for type of soil or other resource, may obscure the tendency to a symmetrical arrangement of functions by degree of indirectness of relationship with key functions.
An important implication of the principles of the key function and of differentiation is that of transitivity in the relation among functional units. Relations with environment are necessarily transitive for some units. By the same token, relations among many units are transitive. The advance of specialization increases transitive relations more than proportionally and lengthens the transitive sequences. Thus, it is possible for functional units widely removed from one another so far as direct encounters are concerned to be inextricably linked through their respective linkages with one or more units performing intervening functions. All functions, regardless of kind, are subject to the environmental nexus. They differ only in the immediacy with which influences reach them. Those which operate at or near the ends of chains of relationships may appear to have large degrees of independence of environment. The appearance is illusory, however. It is due, rather, to the time required for effects to reach them and, in complex systems, to their having positions in two or more relational sequences which expose them to countervailing influences.
Principle of dominance
Given the principles stated above, it is a simple inferential step to a principle of dominance. According to this principle, functional units having direct relations with environment, and thus performing the key function, determine or regulate the conditions essential to the functions of units having indirect relations with environment. Dominance, in other words, is an attribute of function.
But while the power inherent in a system is unevenly distributed, it is not confined to the key function unit. Power is held in varying degrees by all other units, in measures that vary inversely with the number of steps of removal from direct relation with the unit performing the key function. A single power gradient running through all the units involved in a system assumes a very simple situation, of course, one in which a single unit occupies a key function position. Before introducing complications into this overly simplified conception, it is opportune to note some further implications of the dominance principle.
Where the progress of differentiation has distinguished a relatively large number of units, they tend to form clusters or complex units. A corollary to the dominance principle sheds light on how that comes about: the greater the extent to which variously specialized units are subject to the environmental conditions mediated by some one unit, the greater their tendency to coalesce in a corporate body. The interdependence among such units is manifestly close, and their requirements for mutual accessibility are correspondingly acute. A hierarchic pattern emerges in which the number of strata corresponds to the number of degrees that the parts are removed from direct relations with the key function; thus, symbiotic subsystems appear as components of a parent system. The nuclear family, although its origins are obscure, fits this principle. But instances with more proximate origins are found in the combinations of specialists to form producing enterprises, welfare agencies, governing bodies, etc., and again in the combinations of producing enterprises, retail establishments, or governments to constitute larger, more complex units. There is no restriction of scale or complexity in the formation of symbiotic or corporate units.
On the other hand, units that are of a given functional type and therefore occupy equivalent positions in the power hierarchy may raise their power potential by the formation of categoric unions. Any threat to a function or to the conditions of its performance can provoke such a response; groups of elders, the medieval guilds, labor unions, professional associations, councils of churches, retail associations, and associations of manufacturers are examples of categoric units. A social class is at most a loose form of categoric unit.
As with the corporate union, the categoric union may be composed of units of any size or kind. It may appear as a federation of categoric units or as an association of corporate units. So long as it retains its pure categoric form, however, such a unit can do little more than react to circumstances affecting it. Nor can it have more than a transitory existence, since in order to engage in positive action of any kind and to attain some measure of permanence, it must develop at least a core of specialists. Although the categoric unit tends to assume the characteristics of the corporate unit, it remains distinctive as long as its criterion for membership is possession of a given, common characteristic. In any event, the categoric unit is a source of rigidity in a social system, and once formed, its effect is to preserve the position of a functional category in the system.
The concept of dominance has been widely employed for the purpose of delimiting the boundaries of systems. It is argued that centers of settlement, such as cities, exercise dominance over their surrounding areas, in diminishing degrees as the distance from the center increases; the margin of influence marks the boundary of the system. Empirical support for this proposition is provided by the evidence of nonrandom distribution of related functions and by the gradient pattern that appears in the frequencies with which outlying functions are involved with central functions.
Two qualifications of this conclusion are needed; first, dominance is exercised from and not by centers, since it resides in functional units rather than in the places where they are located. Further, the apparent decline of dominance results less from an effect of distance in reducing control over related functions than from the increased difficulty of establishing dominance uniformly over an exponentially widening area.
Isomorphism. A principle of isomorphism has been implied in much that has been said and needs now to be stated. Units subject to the same environmental conditions, or to environmental conditions as mediated through a given key unit, acquire a similar form of organization. They must submit to standard terms of communication and to standard procedures in consequence of which they develop similar internal arrangements within limits imposed by their respective sizes. Each unit, then, tends to become a replica of every other unit and of the parent system in which it is a subsystem.
Since small units cannot acquire the elaborate organizations of which large units are capable, they jointly support specialized functions that complement their meager organizations. For example, whereas a large unit may include among its functionaries accountants, lawyers, engineers, public relations experts, and other specialists, the small unit must purchase comparable services from units specializing in each of the relevant functions. The principle of isomorphism also applies to the size of units, at least as a tendency; that is, all units tend toward a size that enables them to maintain contact with all relevant sectors of the parent system.
Closure and social change
Operation of the several principles mentioned thus far moves a system toward a state of closure. This term must be employed here with circumspection, for it cannot have its usual connotation of independence of environment. Closure can only mean that development has terminated in a more or less complete system that is capable of sustaining a given relationship to environment indefinitely. For closure to be realized, it is required not only that the differentiation of function supportable by the productivity of the key function has attained its maximum but also that the various functions have been gathered into corporate and categoric subsystems; moreover, the performance of the key function should have been reduced to one unit or to a number of units united in a categoric federation. Then a system is highly selective of its membership and capable of exercising some control over factors that threaten change in the system.
Under these circumstances, certain conditions of equilibrium are held to obtain: the functions involved are mutually complementary and collectively provide the conditions essential to the continuation of each; the number of individuals engaged in each function is just sufficient to maintain the relations of the functions to each other and to all other functions; and the various units are arranged in time and space so that the accessibility of one to others bears a direct relation to the frequency of exchanges between them. Needless to say, equilibrium as thus defined is a logical construct; the conditions express an expected outcome if the principles of organization are allowed to operate without any external disturbances.
Origins and effects of change
Every social system is continuously subject to change, for since the environment is always in some state of flux, the equilibrium that can be attained is seldom more than partial. A system founded on nonreplaceable resources is faced with “immanent change”; sooner or later it will either pass into decline or shift perforce to a different resource base. Such, for instance, has been the experience of innumerable mining communities; in a similar manner agricultural communities often alter the soil composition of their lands by the uses they practice, with the ultimate result that the lands will no longer support the systems as they are constituted. Instances of maladaptation, such as the reliance of the Irish on the potato as a food staple in the nineteenth century, can lead to catastrophic consequences.
In general, however, change has an external origin, a proposition that follows by definition from an equilibrium position. Some influences emanate from the physical or biotic environment, such as variations in the growing season or invasion by parasites. To the extent that episodic occurrences of that order fail to modify one or more functions comprised in the system, their effects are transitory; the system returns to its original form. But where a function, particularly a key function, is substantially modified, the system must be reconstituted. The disappearance of a game supply, the silting of an estuary, or the eruption of a volcano may render a key function inoperative in its usual location. The population must relocate and work out a new system of activities. Unless there is an increase of productivity, new ways of acting will merely displace old ways, and the change will not be cumulative.
Cumulative change
Cumulative change, or growth of the system, presupposes an increase in the productivity of a key function. Only in this way is it possible to multiply specialization, to employ a greater variety of techniques, and to support a larger population. The probability of the occurrence of disturbances having that effect rises with the number of points of contact with a social environment; location, therefore, is an important factor. A site on a traveled route is more exposed to external influences than one situated at a distance from an avenue of movement; a site at a conflux of routes is much more vulnerable to disturbances from without. Any location that fosters frequent meetings of people from diverse backgrounds is a gateway for the infusion of alien experiences and techniques into the social system centered there. Whether change is released through a deposit of numerous small additions to the culture or through a simple, dramatic innovation is immaterial.
The process of cumulative change may be generalized as a principle of expansion. Expansion is a twofold process involving, on the one hand, the growth of a center of activity from which dominance is exercised and, on the other hand, an enlargement of the scope of the center’s influence. The process entails the absorption and redistribution of the functions formerly carried on in outlying areas, a centralization of mediating and control functions, an increase in the number and variety of territorially extended relationships, a growth of population to man a more elaborate set of activities, and an accumulation of culture together with a leveling of cultural differences over the expanding domain. After the revival of trade in Europe, from the tenth century onward, the favorably situated village with its narrow vicinage grew into a market town that served as a center of an enlarged territorial organization. That gave way, in turn, to the emergent city capable of exercising an integrating influence over an area of regional scope. Most recently, the metropolis has superseded the city and has brought under its dominion a vast interregional territory. Although the process is as old as recorded history, it has not advanced in a simple linear progression. It has moved and then stalled in one place, only to surge ahead in another; it has faltered and even on occasion has seemed to turn back upon itself, but it has always resumed its course with renewed vigor.
The limits to expansion are sometimes fixed by the facility of movement between center and periphery—by the maximum distance over which the exercise of dominance is feasible. More often than not, however, the limits are drawn at the points of juncture with the expanding domains of social systems in neighboring regions. As a system encounters its limits, however they are fixed, it loses capacity to absorb further change, and equilibrium tendencies begin to assert themselves once more.
In many instances, however, the first symptoms of change are experienced at the periphery of a system. Since the effects of dominance grow more uneven with increased distance from a center, boundaries are apt to be permeable at many points. Yet, in the degree to which a system is integrated, events at the boundary are transmitted directly to the key unit, from which they are communicated to ancillary units; it is always at the boundary that one system begins its absorption of another. Expansion may be resumed at any moment and in any of the systems that hem in one another. An innovation, even though it might present itself to all systems about the same time, gains admission to one or another by virtue of a more favorable location for its use, a more appropriate organization for its acceptance, or some other local advantage. The renewed expansion encroaches upon the territories of adjoining systems, sometimes reducing them to mere components of a single, greatly enlarged system.
Under conditions of closure, environmental effects, and particularly cultural innovations, would be expected to enter a system through the key function, for the obvious reason that it has the most direct connection with environment. And, presumably, change would spread through the system by affecting units successively in the order in which they are removed from direct relation with a key function. But in a system centered on a convergence of routes, many units may have direct, although not equal, access to the outside world. Change may therefore enter the system at many points, at least until its structure is fully developed with the parts systematically arrayed relative to a key unit. An expanding system, in other words, is an open system, and it remains so until the limits to expansion are reached.
Burgess’ hypothesis of city growth
A hypothesis of city growth, stated by E. W. Burgess ([1925] 1961, pp. 37–44), pertains to a special case of the more general principle. According to that proposal, city growth takes the form of expansion from a zone centered on a highly accessible location. Growth involves increasing density of occupance of the central zone and, at the same time, a redistribution of activities or land uses scattered around the center to conform to a gradient pattern of variation of intensity of land use according to distances from the center. Redistribution results from increasing pressure at the center and a consequent encroachment by high-intensity uses into the spaces occupied by lower-intensity uses in a succession-like manner. Alternating periods of redistribution and stabilization of distribution, and those of growth and partial equilibrium, create a wavelike effect more or less visible in a set of concentric zones. By venturing to describe, in rather specific terms, the content of the zones and by thus reifying a set of statistical constructs, Burgess diverted attention from a growth process and caused it to be fixed on a specious distribution pattern. His argument, therefore, seemed to acquire a historical limitation that it need not have had.
The miscarriage of the import of the Burgess hypothesis is evident in criticisms that have opposed the preindustrial city to the industrial city as a qualitatively different phenomenon. Whereas Burgess suggested that the social-economic status of residents is higher in each successive concentric zone, critics have shown that in the preindustrial city the social-economic gradient runs in the opposite direction. Useful as that finding may be, it misses the essential point. That is, the significant gradient is one of dominance; units tend to distribute themselves over space in a way that reflects their relationships to the dominant unit. In this respect, both industrial and preindustrial cities are similar. The qualitative difference lies in the kinds of units that exercise dominance. In the preindus-trial city, all functions are carried in familial or household units, and power is unevenly distributed among them. But in the industrial society, the household unit has been relegated to a minor position; specialized functions are performed by extra-familial units, and the separation of functions from the household has involved a spatial separation as well.
Furthermore, the notion of a monocentered system is applicable only to the simplest instances. All others include a constellation of settlement nuclei, that is to say, subsidiary service centers within cities, and villages, towns, or cities within hinterlands. Each serves as a locus of influence over a localized area, varying in scope with the types of functions centered in the nucleus. Thus, as Christaller observed, the constellation of nuclei forms a hierarchy by size and number of places and by order of functions performed (1933). Small places provide low-order, or ubiquitous, functions, whereas each larger place performs, in addition to low-order functions, higher-order functions for broader domains. At the apogee of the hierarchy is the metropolis, in which the integrating and coordinating functions for the entire system are domiciled. Thus, dominance is exercised downward and outward through nested sets of subsidiary centers [seeCentral Place].
The least satisfactory aspect of the theory of change concerns its temporal incidence. The idea of succession, borrowed initially from bioecology, lingers in the dictionary of human ecology. Change as cyclical in form, consisting in movements between equilibrium stages, is clearly the most intelligible conception. Nevertheless, apart from the difficulty in empirically identifying an equilibrium stage, there are unsolved conceptual problems of the spacing of stages, and of the factors governing the intervals between stages. Thus far, succession has been applied only in retrospect. Its utility will remain uncertain until it can be projected into prediction. Quite possibly, that may have to wait for more extensive work on social system taxonomy.
The limits of human ecology
Human ecology has progressed since its inception from an effort to apply the concepts of plant and animal ecology to human collective life, through an extended period of preoccupation with spatial configurations, to an increasing concern with the form and development of territorially based social systems. In the last phase, human ecologists have sought to clarify the assumptions of ecology and to draw out their implications for organization. Although the results of that work are far from complete, it seems clear that they indicate the direction in which human ecology will continue to develop.
As with most approaches in social science, human ecology has limited objectives. It seeks knowl-ledge about the structure of a social system and the manner in which the structure develops. Hence, it is not prepared to provide explanations for all of the manifold interactions, frictions, and collisions that occur within the bounds of a social system. The findings of human ecology, however, define the context in which all such phenomena take place, and which is therefore pertinent to their full understanding.
Human ecology is not qualified to deal with the normative order in a social system. Yet consistent with its position is the expectation that a normative order corresponds to and reflects the functional order. The two are different abstractions from the same reality.
Amos H. Hawley
[See alsoCity, article onComparative Urban Structure; Environment; Environmentalism; Geography; and the biographies ofBurgess; Darwin; Park.]
BIBLIOGRAPHY
Burgess, Ernest W. (1925) 1961 The Growth of the City: An Introduction to a Research Project. Pages 37–44 in George A. Theodorson (editor), Studies in Human Ecology. Evanston, Ill.: Row, Peterson.
Christaller, Walter 1933 Die zentralen Orte in Siiddeutschland: Eine okonomisch-geographische Untersuchung iiber die Gesetzmdssigkeit der Verbreitung und Entwicklung der Siedlungen mit stddtischen Funktionen. Jena (Germany): Fischer.
Duncan, Otis Dudley 1959 Human Ecology and Population Studies. Pages 678–716 in Philip M. Hauser and Otis Dudley Duncan (editors), The Study of Population: An Inventory and Appraisal. Univ. of Chicago Press.
Hawley, Amos H. 1950 Human Ecology: A Theory of Community Structure. New York: Ronald.
McKenzie, Roderick D. (1924) 1925 The Ecological Approach to the Study of the Human Community. Pages 63–79 in Robert E. Park, Ernest W. Burgess, and Roderick D. McKenzie, The City. Univ. of Chicago Press. -* First published in Volume 30 of the American Journal of Sociology.
Park, Robert E. (1936) 1952 Human Ecology. Pages 145–158 in Robert E. Park, Human Communities: The City and Human Ecology. Collected Papers, Vol. 2. Glencoe, Ill.: Free Press. ? First published in Volume 42 of the American Journal of Sociology.
Quinn, James A. 1950 Human Ecology. Englewood Cliffs, N.J.: Prentice-Hall.
Schnore, Leo F. 1958 Social Morphology and Human Ecology. American Journal of Sociology 63:620–634.
Steward, Julian H. 1955 Theory of Culture Change: The Methodology of Multilinear Evolution. Urbana: Univ. of Illinois Press.
II CULTURAL ECOLOGY
Cultural ecology is the study of the processes by which a society adapts to its environment. Its principal problem is to determine whether these adaptations initiate internal social transformations or evolutionary change. It analyzes these adaptations, however, in conjunction with other processes of change. Its method requires examination of the interaction of societies and social institutions with one another and with the natural environment.
Cultural ecology is distinguishable from but does not necessarily exclude other approaches to the ecological study of social phenomena. These approaches have viewed their special problems—for example, settlement patterns, the development of agriculture, and land use—in the broad context of the complexly interacting phenomena within a defined geographical area. Explanatory formulations have even included the incidence of disease, which is related to social phenomena and in turn affects societies in their adaptations. This modern concept of ecology has largely superseded other concepts, such as “urban,” “social,” and “human” ecology, which employed the biological analogy of viewing social institutions in terms of competition, climax areas, and zones.
Cultural ecology is broadly similar to biological ecology in its method of examining the interactions of all social and natural phenomena within an area, but it does not equate social features with biological species or assume that competition is the major process. It distinguishes different kinds of sociocultural systems and institutions, it recognizes both cooperation and competition as processes of interaction, and it postulates that environmental adaptations depend on the technology, needs, and structure of the society and on the nature of the environment. It includes analysis of adaptations to the social environment, because an independent tribe is influenced in its environmental adaptations by such interactions with its neighbors as peaceful trading, intermarriage, cooperation, and warfare and other kinds of competition, in the same way a specialized, dependent segment of a larger sociocultural system may be strongly influenced by external institutions in the way it utilizes its environment.
The cultural ecological method of analyzing culture change or evolution differs from that based on the superorganic or culturological concept. The latter assumes that only phenomena of a cultural level are relevant and admissible, and it repudiates ”reductionism,” that is, consideration of processes induced by factors of a psychological, biological, or environmental level. The evolutionary hypotheses based upon this method deal with culture in a generic or global sense rather than with individual cultures in a substantive sense, and they postulate universal processes. Cultural ecology, on the other hand, recognizes the substantive dissimilarities of cultures that are caused by the particular adaptive processes by which any society interacts with its environment.
Cultural ecology does not assume that each case is unique. Its method, however, requires an empirical analysis of each society before broader generalizations of cross-cultural similarities in processes and substantive effects may be made. Cultural ecologists study highly diversified cultures and environments and can prescribe neither specific analytic formulas nor theoretical or ideal models of culture change; there can be no a priori conclusions or generalizations concerning evolution. The heuristic value of the ecological view-point is to conceptualize noncultural phenomena that are relevant to processes of cultural evolution.
Empirical studies disclose that among the simpler and earlier societies of mankind, to whom physical survival was the major concern, different social systems were fairly direct responses to the exploitation of particular environments by special techniques. As technological innovations improved man’s ability to control and adjust to environments, and as historically derived patterns of behavior were introduced, the significance of both the environment and the culture was altered and the adaptive processes not only became more complex but also acquired new qualities.
The ecological concept of interacting phenomena draws attention to certain general categories of relevant data. The resources, flora, fauna, climate, local diseases and their vectors of occurrence and many other features of the environment constitute potential factors in one part of the interacting system. The nature of the culture, especially its exploitative and adaptive technology but also features of the internal and external social environment, constitutes the other part. The interaction involves the social arrangements that are required in land exploitation; population density, distribution, and nucleation; permanence and composition of population aggregates; territoriality of societies; intersocietal relationships; and cultural values. In each case the empirical problem is whether the adaptation is so inflexible as to permit only a certain pattern or whether there is latitude for variation which may allow different patterns to be developed or borrowed.
Explanations in terms of cultural ecology require certain conceptual distinctions about the nature of culture. First, the various components of a culture, such as technology, language, society, and stylistic features, respond very differently to adaptive processes. Second, sociocultural systems of different levels of integration profoundly affect the interaction of biological, cultural, and environmental factors. Societies having supracommunity (state or national) institutions and the technological ability to expand the effective environment beyond that of the local or primary group can utilize resources within and outside the area controlled by the larger society. The adaptive responses of complex societies are thus very unlike those of a tribal society, which adapts predominantly to its own environment.
Culture history and ecological adaptations
The historical processes by which a society acquires many of its basic traits are complementary to studies of adaptive processes. The historical processes include the extensive borrowing of many cultural traits and trait complexes from diverse sources; the migrations of people; the transmission of cultural heritages to successive generations; and local innovations or inventions. Recognition of these historical processes, however, does not relegate environment to the circumscribed role of merely permitting or prohibiting certain cultural practices so that all origins must be explained by such history. It is obvious that fishing will have minor importance in desert areas and that agriculture is impossible in arctic regions. It is equally clear that abundant fishing resources cannot be exploited without appropriate techniques and that agricultural potentials cannot be utilized without domesticated plants. The presence of gold, oil, and uranium is unimportant until the society has demands for them and means of extracting them.
The Indians of the Southwest had at one time been predominantly food collectors, but the introduction of food crops, largely from Mesoamerica, provided the basis for the development of the more complex Pueblo village culture. Many details of this culture, such as ritual elements, were borrowed from the south, but the development of Pueblo sociocultural patterns are comprehensible only in terms of the processes of population growth, extension of biological families into lineages, eventual consolidation of lineages into larger settlements, and the appearance of many village institutions that cut across kinship groups.
Dissimilar ecological adaptations may also occur among societies that have been subjected to similar historical influences. The Indians of California and of the semiarid steppes and deserts of the Great Basin shared substantially the same devices for collecting wild foods and for hunting, but the vastly greater abundance of flora and fauna in California supported a population thirty times that of the Great Basin. The California Indians lived in fairly permanent villages which had developed some social elaborations, whereas the Great Basin Indians were divided into independent family units which foraged over large territories during most of the year and assembled only seasonally in encampments that did not always consist of the same families.
The investigation of cultural ecological processes must consider the possibility that basic sociocultural patterns may have diffused or been carried by migrations from one kind of environment to another, but it also must examine whether these patterns have been modified. Assessment of modifications requires a distinction between the outer embellishments of the culture, such as ritual elements, art styles, and kinds of architecture, and those social patterns which are human arrangements for self-perpetuation.
Biological factors
Man’s adaptations to his natural environment cannot be comprehended in purely culturological terms because man not only shares basic biological needs with all animals but also has distinctively human characteristics. All activities are culturally conditioned, but ecological factors cannot be wholly distinguished from inherent biological and psychological factors which are the basis of behavior. Analyses that ascribe importance to inherent human qualities bear directly upon the validity of common hypotheses and raise new problems.
It has generally been assumed that the nuclear family consisting of parents and children has always been the irreducible social structure because the sexes serve complementary functions in meeting procreational and subsistence needs and in caring for and training the young during their long period of dependency. This assumption is generally valid for all ethnographically known societies, especially for primitive societies, among whom there is a clear sexual division of labor in subsistence, maintenance of the household, and child rearing. In contemporary industrial societies, however, the biological family has surrendered many of its functions, and cultural differences between sex roles have been diminished. Conceivably, the nuclear family might be reduced to little more than a procreational unit if its cultural functions are lost.
In primitive societies, larger suprafamilial bands or other groups that developed in response to cooperative needs, especially in subsistence activities, had a biological basis, especially through lineages. The patrilineages of hunting bands, for example, had the advantage that particular skills, knowledge of the environment, and obedience to authority were transmitted from father to son in a male-dominated group. Biological relationships have so long been fundamentally important in culture history that they may be ascribed excessive importance, as when the position of head of a family or even kingship is transmitted through primogeniture. The biological basis survived because of the lack of patterned alternatives.
Another basic biological factor in cultural ecological adaptations is the prolonged period of human growth. The factors of age and environment interact in many ways to affect behavior patterns. The Shoshoni child may help in rabbit drives but not in big game hunting; the east African boy may herd cattle but not go to war; modern American youths attend school for a required number of years; in areas of precarious subsistence the aged may be abandoned to die, while in other areas they may be accorded special consideration; and everywhere the marriage age group is determined by biological development, culture, and adaptations to the environment.
There are, however, many problems concerning the interaction of biological and cultural ecological factors. One of these arises from the assumption that the nuclear or biological family is a basic part of every human society. This assumption might rest on the obvious biological nature of the family or upon the universal cultural functions the family is believed to serve. The higher primates usually live in fairly small bands that consist of females and their dependent offspring, a single powerful male, and subordinate adult males. In certain depressed segments of modern society, however, the matrifocal family or kin group, which consists of women and dependent children and somewhat subordinate males who are loosely attached to the family, appears to be the irreducible social unit. This family represents an adaptive response to restricted territoriality, low income, and lack of opportunity for improvement.
Although the transition from a precultural primate society to the nuclear family has not been explained, the contemporary existence of the matrifocal kin group raises the question of origin. How did the nuclear family develop from an early kind of society which may have lacked the cultural ecological processes that created and have subsequently supported it?
Speculation about the origin of the family must be based on what is known archeologically about the origins of technology and on ethnographic evidence. In all ethnographic cases of pref arming societies the nuclear family is based on clear complementarity of the sexes in subsistence activities. Women are food collectors because they must not leave their children, who are their inescapable responsibility, whereas men may spend long periods away from their families hunting large game or fishing, if the technology makes this possible. Prior to the invention of such distinctly male-associated hunting devices as spears, bows, nets, and traps, both sexes may have collected food in so similar a way that they were no more differentiated than were the higher primates. If so, there may have been a long transitional stage when some type of matrifocal kin group persisted. The hand ax, which was long the principal weapon, may attest to men’s role in protecting the group but not specialization in hunting, for its use was in close combat.
Settlement patterns and the adaptive process
A culture that is introduced into a wholly new environment must adapt in some ways to local conditions, but only empirical research can determine whether the adaptations are unalterably fixed or whether there is latitude for variations. In some instances, the case for narrow limits of variation seems clear. Simple societies that exploit only sparse and scattered resources obtained by food collecting must obviously fragment into small groups, for members of the society are in competition with one another. More abundant resources, such as rich areas of vegetable foods, large game herds, fisheries, or intensive farming, may permit variation in some features and thus allow latitude for borrowing or for local innovations.
There can, however, be no a priori conclusions: whether a society is dispersed over its land or clustered in large settlements may result from adaptive factors, from historical patterns, or from both. The Indians of California and the Northwest Coast had very similar native population densities, but the dispersed acorns and game in California led to considerable dispersal of the villages, whereas the rich salmon fisheries of British Columbia and Alaska required the people to concentrate on the main streams in fairly large settlements. Similarly, agricultural areas dependent upon irrigation concentrated the population within the network of canals. On the rainless and barren deserts of coastal Peru, the people had to live in dense settlements along or near the rivers. The large communities on the coasts of British Columbia and Peru, however, were parts of unlike sociocultural systems. Each developed from a different historical background, and each had a distinctive local adaptation; there were fisheries on the Northwest Coast and intensive, irrigation farming together with ocean resources in Peru.
A dense population supported by a rich economy is not always concentrated in large centers. The native agricultural peoples of the northern Andes of Colombia and the Araucanian Indians of the central valley of Chile had very similar population densities, but the northern Andean peoples were organized in strong, class-structured chiefdoms with communities of five hundred persons or more, whereas the Araucanians were dispersed in many closely spaced villages, each a patrilineage of no more than one hundred persons. This contrast is not explained by farm productivity or other technological factors involved in maintaining large communities. The northern Andean chiefdoms were the result of a diffused cult-complex of temples, priests, warriors, and human sacrifice, which may have originated in Mesoamerica but was re-adapted to the diversified environment of high mountains and deep valleys. Presumably, the Araucanians could have supported chiefdoms, but the nucleating factors were absent. A limited pastoral nomadism based on llama herding may have been an ecological deterrent to community growth, Although this factor did not inhibit the development of states and empires in Peru.
Nontechnological features of culture may also affect the adaptive arrangements through the external social environment of the society. Peaceful interaction of societies through marriage, trade, visiting, and participation in ceremonies, games, and other activities may take various patterns within the limits imposed by the environment. Intergroup hostilities, however, may have a decisive influence, because fear of warfare often causes peoples to cluster in compact settlements that are not required by subsistence patterns and sometimes do not give optimum access to resources. Thus, the palisaded villages of parts of the Amazon some-what inhibited farming of the frequently shifting slash-and-burn farm plots. To judge by the pre-history of the Pueblo Indians, the nature of farming permitted considerable variation. Early settlements were small and widely scattered, but in later periods the population declined as the settlements became large and tightly nucleated. This was the result of increased precariousness of farming in an area that had frequent droughts and was inhabited by marauders. In Tanganyika, people did not dare disperse along the fertile lands near the waterways until colonialism largely eliminated warfare. Throughout much of history, warfare has been a major factor in the interaction of culture and environment.
Exploitation of an environment by means of certain cultural devices may also drastically affect the environment, which again reacts upon the culture. In native California, as in many other areas, the Indians deliberately fired the grass in order to kill seedlings of brush and trees and thus increase the grazing land for game. Deforestation, overgrazing with concomitant soil erosion, the damming and rechanneling of rivers, drainage of swamps, and conversion of rural areas to urban or suburban land-use patterns also alter the environment. In such instances as the firing of grasslands, the development of irrigation works, or reclamation of swamps, the culture increases its basic resources. In others, such as overgrazing, lack of conservation, or the exhaustion of basic minerals, the culture destroys or impairs certain aspects of its local foundations.
Cultural variables versus holism
Although the culture of any society constitutes a holistic system in which technology, economics, social and political structure, religion, language, values, and other features are closely interrelated, the different components of a culture are not similarly affected by ecological adaptations. Technology, which exemplifies progress in man’s control of nature, tends to be cumulative. A language, unless replaced by another one, slowly but continuously evolves into divergent groups of languages. Humanistic and stylistic cultural manifestations may retain their formal aspects during social transformations but acquire new functions. Societies change through a series of structural and functional transformations.
Social structures respond most clearly to environmental requirements. This basic structuring is related most immediately to cooperative productive activity, and it is manifest in community and band organization and in essential kinship systems. Among simple societies, any interpersonal or inter-familial arrangements necessary for survival in particular areas are virtually synonymous with social organization. Because food collecting, such as in the case of seed gathering, is competitive, societies in unproductive environments tend to become fragmented into nuclear family units. Societies of hunters are more productive under cooperative arrangements and attain various patterns of cohesion. Societies that depend primarily upon farming tend to have permanent community organization, whether in dispersed or nucleated settlements, because cooperation in such activities as clearing plots and irrigation projects facilitates production. Increase in productivity is delimited by the environmental potentials, crops, and farm methods, but it may lead to larger communities and to internal specialization of role and status.
Productive increases achieved by social cooperation and improvements in exploitative technology became the bases of the transformation of small, homogeneous societies into larger societies that were internally specialized by occupational role and social status. Structural aspects of cooperation are reasonably well known, but quantitative statements of productivity, potential and actual surpluses, manpower hours that might be available for pursuits other than production of basic necessities, numbers of persons engaged in special occupations, and other measurable activities are rarely available. These serious lacunae in our data leave open the question of the part that sheer quantities of people and things played in the transformations from simple to complex societies.
Even within the category of culture subsumed under social patterns, it cannot be assumed that all features are equally fixed by a given ecological pattern. Among simple societies, residence, kinship, and subsistence patterns are more fundamental and less alterable or variable than clans, moieties, religious and secular associations, and other elaborations which are secondary embroideries on the basic social fabric. Distributional evidence in many parts of the world clearly shows that such elaborations have diffused widely across different kinds of environments and to fundamentally different social structures adapted to use of the environments. In the Southwest, for example, matrilineal clans occurred among the western Pueblo farm villages and the seminomadic pastoral Navajo, and moieties were a secondary adjunct of the patrilineal hunting bands in southern California and some of the eastern Pueblo agriculturalists.
A final problem concerning the response of different aspects or components of culture to adaptive processes is whether old or traditional forms may acquire new functions. Among the Sonjo of Tanganyika, the men’s age-group that served as warriors in precolonial times now spends several years performing wage labor in the new nonmilitaristic, cash-oriented context. Clan-owned or lineage-owned land and traditional types of ownership and inheritance of herds may persist under production for an outside market. Although traditional structures and trait-complexes tend to perpetuate themselves in all stages of cultural development, the evidence seems clearly to indicate that the new functions of the changing context eventually alter old forms beyond recognition, or that these forms wither and are replaced by new ones.
Levels of sociocultural integration
The adaptations of a complex or highly developed society differ in many ways from those of a simple society. The internal specialization that developed after the agricultural revolution and more so after the industrial revolution has affected the adaptive processes of the local segments of states and nations. Land use has increasingly reflected the importance of external economic institutions rather than local subsistence goals. Trade, improved transportation, mechanization, and other factors related to industrialization have made each local social group a more highly specialized and dependent part of the larger sociocultural system. There is a tendency toward monocropping in areas best suited to production of crops for external markets and toward specialization of local extractive industries, such as mining, oil, and timber, which have little intrinsic value to the local subsociety. Larger sociocultural systems have also created metropolitan and industrial centers and set aside special recreational areas.
Owing to technological achievements, the impact or conditioning effects of nature upon society are far less direct and compelling in a complex society than in a simple one. Culture increasingly creates its own environment. Foods and other necessities can be transported, water diverted, and electric power transmitted great distances. Reasonable comfort can be provided even for those who live for a time in Antarctica.
In a more fundamental sense, however, the distinction between primitive and developed societies is not merely one of social complexity or of technological knowledge. Among primitive peoples, the family, extended kin group, or fairly small village or band adapts directly to its own territory. Among more complex societies, there are suprafamilial and supracommunity institutions that are impersonal in that they do not involve the total cultural behavior of the people connected with them. State economic institutions—corporations, for example, that extract new materials and manufacture and distribute the products—serve the varied needs of the many subcultural groups within the state. They also extend the interaction of culture and environment far beyond state boundaries through the exploitation of distant resources and through extensive commerce. These vast economic extensions of the more developed societies penetrate local societies, and by creating new uses for land and other resources and imposing outside political and economic patterns, they fundamentally transform the local societies.
Within a modern, complex state, there is increasing specialization of land use within environmental potentials, but distinctiveness of local subcultures is partly leveled by the impact of national influences. The subcultures of ranchers in Nevada, sugar-cane workers in Puerto Rico, tea-plantation workers in Kenya, and other subsocieties who live on the land are shaped by the outside economic institutions to which they are linked, as well as by the local environment. As technology develops and sub-societies become more dependent upon the larger society, direct adaptation to the local environment decreases. The way of life, or subculture, of business executives of New York City, for example, has become dichotomized: in part it is derived from their highly specialized occupational role in a city and in part from their residence in suburbia, where the family and neighborhood culture differs from that of their profession and neither is closely adapted to the local environment. Even more remote from direct environmental impact are certain urban institutions found in contemporary Nevada, where the divorce, gambling, and entertainment complexes are linked to special aspects of the total national culture rather than to the semideserts of the Great Basin.
Some substantive applications
The concept of cultural ecology may be clarified by a number of substantive applications. These cases range from simple to complex societies, from the most elementary level of sociocultural integration to higher levels.
The precursors of man lacked culturally derived devices for killing game and for gathering, storing, and preparing food. They were food scavengers, and any food they collected was preserved without culturally prescribed techniques. Because animals can best forage a known habitat, they may have lived in groups or bands that were somewhat territorially delimited. Any social structuring was probably biologically oriented around the male’s dominance and protection of the group and the female’s role of caring for the young.
When culture provided more efficient techniques for survival, the essential human biological facts of sex, age, and kinship continued to affect the nature of society but were patterned in various ways by cultural ecological adaptations. Where the principal resource was seeds, roots, fruits, insects, small mammals, or shellfish, which occur sparsely, food gathering was necessarily competitive rather than cooperative because the yield decreases with the number of families that exploit the same site. If the local occurrence of principal resources varied each year, as it did among the Shoshoni Indians of Nevada, a multifamily society of permanent composition was not possible. Each Shoshoni family was linked with other families through intermarriage, through largely fortuitous association at a winter campsite, and through brief cooperation during antelope and rabbit hunts wherever there happened to be game. There were no bands of constant membership and no claims to territory or to resource areas. These families were not free wanderers, however, for any human society more effectively exploits a territory familiar to it.
The Chilean archipelago is completely unlike the Great Basin, but the erratic occurrence of shellfish, which was the principal food of the Alacaluf Indians, was functionally similar to Great Basin resources in preventing the formation of permanent social units larger than the nuclear family. That the nomadic, food-collecting family was the irreducible social unit in both cases is a function of the biological factors underlying marriage, division of labor, and child rearing. The independent nuclear family, however, is rarely reported ethnographically, and its occurrence in history is an empirical question rather than a matter of deduction from evolutionary principles.
Many societies fragment seasonally into family units of food collectors, but if the resources are sufficiently abundant and their whereabouts is predictable, the same families maintain contact with one another in loose groups that associate for supra-familial activities. Examples are the Indians of California, who subsisted on acorns, and the Indians of Lake Superior and the upper Paraguay River, who gathered wild rice. It appears that such groups tended to consist of extended families or lineages, although the evidence is not clear on this point.
Hunting generally requires cooperation, but there are various kinds of hunting societies, each reflecting special ecological adaptations. The Central Eskimo, whose population density was one person to 250 square miles or more, lived in small, some-what isolated family clusters. Since some cooperation was necessary in arctic hunting, nuclear families could not well have survived alone.
In societies that hunted large herds of bison, the concentrated resources supported bands of several hundred persons that exceeded the size of traceable lineages and consisted of many unrelated kin groups. The clans among certain Plains Indians were fictitious kinship extensions and an embellishment of the basic subsistence group. The Plains bands were more tightly integrated than the hunting bands of Canada, because game herds were larger, cooperative hunts were more highly developed, and warfare, especially after horses were acquired, became a major factor. By contrast, hunters of small and less-migratory game herds cooperated in bands of thirty to sixty persons who constituted a patrilineal lineage that controlled territorial resources, married outside the band, and brought wives to the husband’s band.
The basic social structure of these types of bands is essentially an interfamilial arrangement that is a necessary—or an optimum—organization for survival, depending on the conditions. A historical explanation that they originated elsewhere and were introduced to the areas through diffusion or migration is not credible, especially in the case of the patrilineal hunting bands that occurred in South Africa, Australia, Tasmania, southern California, and Tierra del Fuego. Each is a special kind of evolutionary development.
Societies of early farmers seem also to have been small, except where intercommunity warfare forced the people to concentrate in protected villages, and each probably consisted of lineages that tended to bud off as long as land was available. Although few analyses of the ecological adaptations of such farmers have been made, several types are suggested. In tropical rain forests such as the Amazon basin, where root crops were staples, slash-and-burn cultivation together with rapid soil exhaustion required the frequent shift of plots and sometimes villages. In addition, dietary needs made riverine protein foods of major importance, and canoe transportation facilitated the concentration of the population along rivers. In temperate areas, such as the United States, there was a marked contrast between the small villages of woodland farmers, who contended with prairie sods or forests, and the river-bottom farmers, as in the Mississippi system, whose fertile soils, once cleared of vegetation, supported large communities that were able to adopt the temple-mound complex from Mesoamerica.
In several temperate, and areas, early farming was restricted to flood plains or to the rainy high-lands. Increased population density in the valleys—made possible by irrigation in such cases as Peru —led to theocratic and militaristic states, whose power extended over wide areas, and to urban centers, which were the containers of civilization. It is not now clear to what extent trade, based upon increasingly specialized local production in adjoining areas, religious cults, and militaristic controls regimented the people to achieve maximum production and fill special statuses and roles.
Animal domestication entailed other kinds of ecological adaptations. Herds require more land for subsistence purposes than farming, have to be tended and moved about, and may be subject to theft. Claims to exclusive grazing areas were difficult to enforce until barbed wire was mass-produced in the last century. Cattle stealing and consequent intergroup hostility could therefore develop, as they did among many cattle breeders of east Africa. Free-roaming livestock, moreover, is a threat to crops, and until recently, farmers had to fence out the animals.
When societies became mounted, for example, the horse or camel nomads, other special adaptations occurred. They became more efficient hunters or herders and could transport foods a greater distance, thus extending their areas of exploitation and permitting larger social aggregates to remain together. They could also engage in predatory activities against one another and their settled neighbors. Mounted predators even created several ruling dynasties in the empires of the Middle East, China, and India.
After the agricultural revolution, the development of supracommunity state- or imperial-level institutions extended the areas of resource exploitation beyond those occupied by any of the subsocieties that were welded into the larger sociopolitical unit. Each local subsociety, although adapted in some measure to its terrain, became a specialized part of a new kind of whole to which it contributed different foods, raw materials, products, and even people—all for state purposes.
The industrial revolution enormously expanded the areas of exploitation through its improved transportation, mass manufacturing, communications, and economic and political controls. Its technology also gave importance to many latent resources. Modern nations and empires embrace highly diversified environments and draw upon areas beyond their political boundaries. Their technology may modify environments to meet their cultural needs, and, above all, any localized subsociety reacts to a complex set of state institutions, to a diversified social environment, and to a large number of goals other than survival. Although people necessarily live in particular places, members of highly industrialized nations must be viewed as increasingly nonlocalized to the extent that their behavior is determined by a great overlay or elaboration of cultural patterns that are only remotely connected with particular environments and are even minimizing some of the child-rearing and economically complementary functions of members of the nuclear family. It can be imagined that nuclear power, hydroponic and synthetic food production, and other technological developments might create wholly artificial environments, as in a permanent space station.
Julian H. Steward
[See alsoCulture, article onCultural adaptation; Evolution, articles onHuman EvolutionandCultural Evolution. Other relevant material may be found inHunting and gatheringandKinship.]
BIBLIOGRAPHY
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Helm, June 1962 Ecological Approach in Anthropology. American Journal of Sociology 67:630–639. ? Includes a review of the literature of cultural ecology.
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Sahlins, Marshall D.; and Service, Elman R. (editors) 1960 Evolution and Culture. Ann Arbor: Univ. of Michigan Press.
Steward, Julian H. 1955 Theory of Culture Change: The Methodology of Multilinear Evolution. Urbana: Univ. of Illinois Press.
Washburn, Sherwood L. (editor) 1961 Social Life of Early Man. Viking Fund Publications in Anthropology, No. 31. Chicago: Aldine.