Population Ecology and Life-History Strategies: The Shaping of An Alternative Worldview

The aim of the present chapter is, through the presentation of a specific case-study, to analyze the dynamic of scientific process, specify the factors that affect it and describe its methodological and conceptual transformations. The concept of “field” was chosen as the unit of study. “Field” is defined as a context of scientific activity consisting of a theoretical core, a subject of research, a vocabulary and research tools.

The focus of the present study is on the field of life history studies and its transformations through time. The specific field was developed during the 1950s, as an attempt to cure the deficiencies of the theoretical framework of population ecology, which rendered research on life history characteristics descriptive and incoherent. The catalyzing factor for the emergence of the field of life history strategies was the interdisciplinary impacts, and especially the impact of neodarwinism. The elaboration of a new theoretical core, also invoking methodological shifts, was the triggering factor for the establishment of the new field.

Until the 1950s, the research tools of the field, such as Lotka’s characteristic equation, focused on density-dependent factors as the factors determining life history strategies. However, questions were soon raised concerning the suitability of such methodologies, especially the mathematical tools. Specifically, the latter were criticized as being unable to describe in a synthetic way the interaction between organism and environment, as well as to embody fundamental concepts like “strategy”.

During late-1960s MacArhtur introduced the model of “r-K selection”, which was the first model providing results concerning the life history strategy of an organism. It also succeeded in describing a mechanism of natural selection determining life history strategies. The worldview embedded in the “r-K selection” model is characterized by determinism, equilibrium and homogeneity, while its approach remained largely reductionistic. The abiotic factors, as well as the dynamic nature of the organismenvironment relationship were in fact not taken into consideration.

Within the framework of habitat templets models introduced in mid-1970s, the focus of research shifted towards environmental causal factors, considering density-dependent phenomena as by-products of the environmental impact. That implied an important shift in causality as well as in the worldview of life history theorists: population was no longer considered as a closed system isolated from the environment. Methodological changes were also important: The theoretical framework of the field combined holistic and reductionistic insights, using a variety of heuristic models. This imposed a new conception of generality as well as of the structure of scientific theories.

Keywords: Population ecology, Emergence of scientific fields, Neodarwinism, Theoretical core, Density dependence, r-K selection, Habitat templates.