Historical Biogeography: Geography as Evolution, Evolution as Geography

Charles H. Smith, Western Kentucky University

Abstract

"Geography" has traditionally been assigned the role of handmaiden in evolutionary studies. In this work a different understanding of the relationship between biological change and locational setting is developed: evolution as a dynamic form of spatial interaction. In the causal model presented, adaptive change is portrayed as a negative feedback response contributing to a general spatial-temporal process of resource cycle tightening involving exchanges between the two fundamental structural sectors ("abiotic" and "biotic") of the earth's surface system. As such, it is rejected as "evolution" per se. This position makes it possible to circumvent the "adaptation yields adaptation" circularity, and to view locational circumstances as being evolutionarily causal, yet not deterministic with respect to population-level change. A parallel interpretation of the relation between range and range change and evolution is also implicit; the individualistic hypothesis is thereby superceded by a model of community evolution allowing for individualistic rates of population (adaptive and) range change, but operating on the principle that populations should tend to change range in common directions (as a response to spatially-varying degrees of efficiency of turnover of resources vital to biotic sector function). This in turn leads to the possibility of normative biogeographic modelling. Comment is also made on the relationship of the present understanding to disequilibrium and dynamic equilibrium interpretations of evolutionary change, and to human cultural evolution. KEY WORDS: geography, evolutionary theory, adaptation, biogeography, individualistic hypothesis, resource cycling.