| This thesis discusses the history of theoretical and experimental approaches to the biology of populations, which later gave rise to the discipline of population ecology. Using different, though related, historical examples, it examines the basic dilemma that confronted those engaged in population studies from 1920 to 1950: how to simplify a complex problem by using mathematical models, while avoiding the danger of losing sight of the real world. The first case study concerns the polemical debate over the logistic curve, invented by American biologist Raymond Pearl in 1920 and heavily promoted thereafter as a law of population growth. Pearl's claims were subjected to vigorous criticism over the next fifteen years by statisticians, economists and biologists, but the logistic curve survived because of the efforts of the American mathematician Alfred James Lotka and the Russian ecologist Georgii Frantsevich Gause. Lotka analysed the equation from the demographic standpoint, while Gause showed how it could be used to study competition in an ecological context. The thesis then examines Lotka's theoretical research in greater depth, and probes the background of his unusual world view, which combined a 19th-century sensibility with 20th-century concerns to create a new science of physical biology having a strong ecological orientation. From there, the thesis explores other mathematical developments of the 1920's and 1930's in population biology, in particular those of W. R. Thompson, Lotka's Italian counterpart Vito Volterra, and Australians A. J. Nicholson and V. A. Bailey. A discussion of the relationship between these researchers and parallel studies in population genetics leads to consideration of the ecological context at the time these works appeared. The thesis then examines the response of the ecological community to mathematical ecology and the experimental research to which it gave rise, with emphasis on the experiments of G. F. Gause. After indicating how these disparate lines coalesced into the discipline of population ecology in the early 1950's, the thesis ends with a review of the various theoretical points of view in terms of their projected strategies of model building. In general the thesis shows that uncertainties about the role of model building in population ecology have existed from the beginning and arose from conflicts between the precise goals of applied science--to predict and to modify nature--and the broader goals of basic ecological research. |
