ABSTRACT
As explained in the Introduction, a major objective of this book has been to argue from cause to effect. Thus it has been shown how certain molecular interactions between pollutants and their sites of action in living organisms can lead to sequential changes starting at the biochemical and physiological levels, progressing to effects on the whole organism, and eventually to effects at the levels of population, community, and ecosystem. Of course, many effects at the biochemical level are not translated into consequent changes at higher levels. A fundamental problem in ecotoxicology is to distinguish between situations in which such molecular interactions cause harmful effects at the population level from situations that do not.
