La notion de population en dynamique et génétique des populations

Abstract

Theories in ecology are based on a paradox: a universal definition of natural populations does not seem to be widely accepted. Two points of view exist among researchers: a mathematical approach to populations and a biological one. First, we quote the successive definitions proposed for populations, both by population geneticists and biologists. A second part accounts for different kinds of populations: closed, open, contiguous, subdivided and metapopulations. Third, we review the main methods for defining natural populations: marking of individuals, gene flow estimation, level of genetic differentiation, estimation of scale domain, level of synchronisation. In a last part, we show the limitations of the mathematical viewpoint of populations in ecological theories. However, the ecological approach based on the study of individual interactions, especially those linked to reproduction, needs to overcome many practical and methodological difficulties that are briefly summarised. We suggest that the ecological literature contains only a restricted number of physical models of natural populations. From our point of view, population geneticists and biologists seem to perceive and study populations in different manners. A pluri- and interdisciplinary approach is required to face the high complexity of the population concept.