Mazess_1978[1]

Mazess_1978[1] - '7‘ Adaptation A Conceptual ’...

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Unformatted text preview: '7‘, Adaptation: A Conceptual ’ Framework Mazess, RN. .1978 “Adaptation: A conceptual framework”. In: Evolutionary Models and Studies in Human Diversity. R.L..Meier et al., eds. Pp. 9-15. The Hague: Mouton. ' . RICHARD B. MAZESS During the past decade interest has been growing in the topic of adapta- tion in both cultural and biological anthropology. However, even books ‘ and articles purporting to deal with adaptation contain little or no discus- ! sibn of the concept itself, nor do the topics dealt with revolve. around some central/focus that can be discerned as adaptational. There is talk of “evolutionary” perspectives and “ecological” relationships, but little systematic distillation of ideas. This appears to reflect the lack of consen- sus as to the meaning of the term adaptation in both the biological and the social sciences, a deficiency that has led to considerable imprecision, made for unwarranted and unseemly speculation, and given rise to suit- able skepticism and even condemnation. Reproaches are not the aim of > this report; rather, the goal is to outline an encompassing conceptual framework. This framework has been formulated chiefly to deal with problems of assessing human biological adaptability, but the possibility of its extension to wider spheres is obvious. THE MEANING OF ADAPTATION The effort to define adaptation is not merely a terminological exercise, but rather the expression of a conceptual framework. The conventional “dictionary” definition of adaptation indicates that it is an adjustment to environmental conditions which enables the organism to survive and function. Prosser (1958, 1964), in one of the few attempts to deal sys- tematically with adaptation, has incorporated this common usage in his definition of “physiological adaptation.” He includes as adaptive the idea of any properties of organisms favoring survival or maintenance of func- tion in an environment, particularly a stressful or changing environment. Other scholars (Eagan 1963; Folk 1966), in their examination of adap» 111 125 126 10 RICHARD B. MAZESS tive terminology, have supported Prosser and advocated continued use of adaptation as an all-inclusive term. This use is far less restrictive and specialized than that of evolutionary biologists and some physical anthropologists, who deal almost entirely with genetic adaptation from an evolutionary perspective, yet it is less broad than that of evolutionary . and functionalist anthropologists, who are prone to see any and all sociocultural characteristics as adaptive. I, too, propose that adaptation be used as an all-inclusive term, but that it be used in well-defined relation to environmental adjustments. The essence of that adjustment involves the notion of properties deemed “necessary,” or relatively “beneficial.” Survival, the first aspect of the definition of adaptation, is equivalent to necessity, while maintenance of function, the other aspect of the conven- tional definition of adaptation, is considered an example of a relatively beneficial property. Necessity and relative merit are the sine qua non of adaptation and constitute the basis of “adaptive significance.” 1 . Adaptive significance is not a notion peculiarly germane to individual organisms or groups of organisms, but it may be applied at any level of p organizational complexity -— enzyme, organ, or ecosystem; that is, adap- tation may have different referents. Moreover, degrees of necessity or of relative benefit or merit must be demonstrated accordingly in detail, and the criteria vary for different referential levels. The adaptive response of an enzyme to substrate alterations is evaluated differently than is’ the ~ adaptive response of a population to a changing climate. Finally, it is proposed that the informational value and import of the term adaptation in a larger comext' derive from the demonstration of adaptive signifi- cance across referential levels. REFERENTS OF ADAPTATION The referents of adaptation do vary, depending on the field of study, and the term adaptation can be used in referring to different levels of bio- logical and social complexity. In the biolbgical sphere there is a fairly clear-cut organizational hierarchy from the physicochemical level to the ecosystem. The properties and characteristics at each level are distinctive, and each level is operatidnally isolated from other levels for analytic purposes and has its own language. Each succeeding level of the biologi- ' cal hierarchy forms the dominant environmental focus of the preceding level. Thus the environment of the cell is the organ system and, of the organ system, it is the organism. " In sociocultural organization the hierarchy of the referential levels is not as clear as the biological hierarchy, but there is an analogous system for organizing individual behaviors, group activities, societal functions, and cultural patterns. Here, as in the biological hierarchy, the “environ- Adaptation: A Conceptual Framework 11 merit” Can be conceived of as the succeeding level of complexity. Thus the adaptive significance of an individual behavior can be examined in rela- ‘ ._ tion to the groups containing that individual, or the functioning of an economic system can be viewed in relation to the total cultural pattern. It is important to specify the referential levels and hierarchical system one is dealing with when assessing adaptation because the criteria of adaptive significance vary from level to level. Confusion will result from not attending to this caveat. For example, if the referent is an enzyme then the criteria of adaptive significance should be germane to that level. and the immediate environment of the enzyme must be considered. In biological anthropology there is often confusion or equivocation between individual and population adaptation, and the criteria of adaptive signifi- cance for individuals are assumed to hold as well for populations. ADAPTIVE SIGNIFICANCE AND ADAPTIVE DOMAINS Degree of necessity and of relative” benefit are concepts that can be defined specifically in relation to certain areas of life, or “adaptive domains.” These operationally defined domains differ at different levels of biological and social complexity. In the biological hierarchy the major emphasis at the physicochemical, cellular, and organ system levels is on the ability to survive or to maintain homeostasis. For individual organ- isms several major aspects of living are considered adaptive domains: 1. Reproduction: survival, reproductive advantage. 2. Health: morbidity, mortality, disease resistance. 3. Nutrition: nutrient requirements and utilization. 4. Nervous system: sensory, motor, and mental functions. 5. Growth and development: physical and mental progression in rate and attainment. ' g 6. Resistance and cross-tolerance: generalized stress resistance. 7. Physical performance: exercise and motor abilities and skills. 8. Affective function: happiness, sexuality, tolerance. ‘9. Intellectual ability: learning, expression. These domains are the basis for assessing the significance of human adaptability. At the level of the population the emphasis is placed.0n evaluating necessity and benefit in relation to size, density, and distribu- tion of the population, and in relation to its biological composition and organization. At the ecosystem level, one considers the interrelations among populations and the attainment of a steady-state or climax. Total energy balance and species diversity and persistence are other domains at this level. 127 128 Evaluation of the adaptive significance of can be made on the relationship of these domains at the individual an I examine the effects of a group behavior, medical treatment, on healt germane to the sociocultural hierarc been attempted here. One of the greatest shortcomings o tation has been the failure to consider advantageous trait ship of a characteristic or response must be demo these environmental relati correla surface area: weight ratio and e nose dimen adaptive significance is at lea adaptive relationship. Thus, increased surface areazweight ratio were tions in hot climates it w increase was of some benefit to an a physical performance, decrease morbidity, tolerance in this climate not answered; the detailed demons tial. Moreover, the informationa increased if such a demonstration is pos hierarchy. A good example of t tionship of the sickle cell gene to ma modifies a cell’s functioning and pro individuals and to the population. Demonstration 0 several levels of the biological hie ' ' attempted by Folk (1966) and Eagan (196 12 mount: 13. MAZESS sociocultural phenomena phenomena to biological d population level. For example, one may such as the institutionalization of h. It is also possible that adaptive domains hy may be delineated, but this has not f modern research on human adap- the adaptive value of putative 5. Of course, it is true that the environmental relation— nstrated; all too often. onships are imprecise, or based on dubious tion as for example the widely touted relationship between the nvironmental temperature, or between sions and relative humidity. However, the failure to consider st as debilitating to the establishment of an even if it could be demonstrated that an an invariant response of popula- ould still be mandatory to demonstrate that this daptive domain. Does it increase or perhaps increase affective ' ? These are questions which must be examined, if tration of benefit or necessity is essen- l impact of such an analysis seems sible over several levels of a his contention is the widely quoted rela- laria. Here a physicochemical change vides a demonstrated advantage to f advantage over rarchy makes this relationship highly informative. NOMENCLATURE ed with adaptation; for example, ac- A specialized nomenclature such as 3) is, in fact, necessary, for as acclimatization, acclimation, cl interchangeably because the denote usually overlap and A variety of terms are associat climation and accommodation. Dubos (1965:56) has pointed out “. . . adaptation, and habituation are often use processes these words are supposed to because the fundamental mechanisms involved are poorly understood.” Such a systematic "nomenclature for organismic adaptability has been developed, but it can be only outlined here. The essence of that system Adaptation: Conceptual Framework 13 lies in the utilization of acclimatization to include all phenotypic adap- tive responses, and to subdivide acclimatization into categories of struc- tural (morphological), functional (physiological), and psychobehav- ioral acclimatization. Habituation here is viewed as a particular kind (neurological) of functional acclimatization, whereas accommodation is defined as a particular kind (affective) of psychobehavioral acclimatiza- tion. Regardless of the category of acclimatizational response, the adap- tive significance has to be shown to render such an assessment more than . speculative. THE STUDY OF HUMAN ADAPTABILITY There are several approaches to the study of human biological adaptabil— ity. Simple trait analysis, whether of cranial dimensions or gene frequen- cies, is least likely to provide useful information, since such studies seldom provide information on environmental relations or on adaptive signifi- cance. Distributional studies, such 'as the examination of geographic gradients or clines, tend to provide only superficial environmental cor— relations and, again, adaptive significance is not assessed. Population studies, particularly those from an ecological perspective, tend to yield an overabundance of often poorly integrated data. Moreover, demonstra- tion of adaptive significance requires controlled comparisons in order to demonstrate degree of necessity or benefit, and this is impossible if only a single population is studied. _ The most advantageous approach to date is the examination of responses to specific deviant environments; that is, a stress-adaptation approach. Characteristics related to a particular stress, such as cold, population crowding, or social disorganization, may be discovered by study of several populations subject to the stress. After an environmental relationship is demonstrated, its import with regard to adaptive domains ' can be examined. It seems likely that a combination of the stress- adaptation approach with population studies, along a micro- environmental gradient, would enable clearer and more controlled defi- nition of environmental relationships and adaptive impact. Totally distinct from the above approaches, but at least equally impor- tant, is the effort to establish a coherent set of adaptive criteria through the study of value systems and their relationship to adaptive domains. Such definition of adaptive domains is especially needed for the sociocul- tural hierarchy. The study of the relationships of environmental responses to adaptive domains, however established, can lead to generalizations with regard to adaptability. For example, adaptations may be classified with respect to strength and duration of stress exposure, age at first exposure and con- 129 130 14 RICHARD B. MAZESS s‘tancy of exposure, and rate and reversibility of the response. With regard to human adaptation to climate, it appears that short-term acclimatiza- tion is most important, long-term and developmental acclimatization is of secondary import, and genetic adaptation is of little import in providing . adjustment to climatic stresses. Human adaptation to disease stresses may exhibit a markedly different pattern. It is interesting to note that for a variety of different stresses, differences among populations in adaptive responses appear to be chiefly the result of developmental acclimatiza—y tion. Formulations of this type, when thoroughly documented, can serve for construction of a theory of human adaptability. Modern science has eschewe our observations may be value free. V questioned by social scientists. The contemporary interest in adaptation indicates that we are anxious to make value judgments and that the scientist and the layman alike will do so. If this is the case, then there is an obvious need for operational precision and accuracy in assessing adapta- tion, and this brief frameWork isithe preliminary outline for dealing with the problem. , The theory of adaptation Evaluation of adaptation require has a noteworthy similarity to ethical theory. 5 examination of necessity or relative benefit, while judgments of necessity, or obligation, and of evaluation constitute the twin bases of ethics (Sesonske 1964). For ethics, however, the orientation is toward judgments by the individual and these are considered as absolutes. In contrast, the orientation of adaptation is toward judgments about which, it is hoped, there is consensus, and these judgments are used operationally to examine environmental responses and classes of responses in the biological and sociocultural hierarchies. The study of adaptation may or may not be ethical, but whatever the case, if it tends to provide us with a more comprehensive and less confused picture of environmental responses, and even to make us happier, we surely can view it as adaptive. REFERENCES DUBOS, n. ‘ 1965 Man adapting. New Haven: Yale University Press. EAGAN, c. J. ‘ 1963 Introduction and terminology. Federation Proceedings 222930 FOLK,'G. E., JR. —932. 1966 Introduction to environmental physx'ology. Philadelphia: Lea and Febiger. L7 lu_fi .. . Adaptation; A Conceptual Framework 15 PROSSER, c. L. 1958 “General summary: the nature of physiological adaptation,” in Phys- iological adaptation. Edited by C. L. Prosser, 167-180. Washington, DC: American Physiological Society. 1964 “Perspectives of adaptation: theoretical aspects,” in Handbook of physiology, section four: Adaptation to the environment. Edited by - D. B. Dill, E. F. Adolph, and C. G. Wilber, 11-25. Baltimore: Williams-Wilkins Waverly Press. SESONSKE, A. 1964 Value and obligation: the foundation of an empiricist ethical theory. New York: Oxford University Press. ~ 131 ...
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Mazess_1978[1] - '7‘ Adaptation A Conceptual ’...

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