ABSTRACT
The science of ecology provides the bases for examining the effect of a foreign substance on the diversity of organisms as well as the possible relationships between them and with the environment. A hierarchical order prevails in nature, and it is the task of ecology to decipher it. Ecotoxicology, which focuses specifically on foreign substances, draws on nearly all of the subdisciplines of ecology, from genetics and ecophysiology to the mathematical simulation of whole ecosystems. Ecotoxicology must allow for the inherent inadequacies and uncertainties of ecology as a stochastic and highly complex science. It is important to bear in mind that ecotoxicology is a specialized science which tends to assign too much importance to its object of study foreign substances in the overall dynamics of ecosystems. Another constraint faced by ecotoxicology is that many ecological methods do not permit any clear-cut legally valid conclusions to be drawn about the effects of foreign substances in populations and ecosystems.
