Evolutionary human paleoecology: climatic change and human adaptation in the Pahsimeroi Valley, Idaho, 2500 BP to the present
Two interdependent lines of thought are now converging into a form of archaeology herein called evolutionary human paleoecology, with a foundation in ecology and Darwinian evolutionism and comprised of variables measurable in the archaeological record, this approach promises to illuminate not only the processes of cultural evolution, but also those evolutionary processes common to all self-replicating mechanisms. It is suggested that if archaeologists are to approach this goal, we must develop means for studying the influence of the ultimate evolutionary process, natural selection, on individual episodes of change.Toward this end, a method is introduced for investigating the evolutionary relationship between human adaptation and climatic change in specific instances. A systematic decision-making model, this method sequentially employs data on adaptive patterns (the "fossil" of human adaptive behavior), the ecological niche, effective environment and biophysical environment to test six alternative hypotheses. These hypotheses address whether an observed change in the archaeological record may actually result from natural selection and, if so, whether the shift in selection pressure that may have caused the change was exerted internally (through the innovation of new variant forms of behavior: Mode 1) or externally (through the action of a changing environment on existing behavioral variants: Mode 2). If change occurs in Mode 2, further hypotheses posit the cause for environmental change. Extensive consideration is given to the appropriate sources and quality of data.Utility of the method is demonstrated in a study of the Pahsimeroi Valley, Central Idaho. Concentrating on the steppe zone, the study obtained data on land use and settlement patterns for the period 8000 BP to AD 1975 and acquired information on the human niche and paleoenvironments for portions of the last 3000 years. Paleoenvironmental data, including paleontological, palynological and dendroclimatological records, all were derived from sources independent of each other and of the archaeological record.Analysis focuses on two episodes of change in local human adaptations: a shift in hunting patterns and settlement (social group) size around 400 BP and a change from sedentary-based pastoralism to periodic, big game hunting in the mid twentieth century.
- Anthropology