In the last 25 years, we have witnessed a revolution in the way that ecologists and evolutionary biologists approach their disciplines. This revolution has been fueled by the ability to dissect the genetic and molecular basis of variation that is partly the currency of these disci- plines. Using modern molecular techniques, we have begun to restruc- ture the spectrum of questions that can be addressed in studying the mechanisms and consequences of the ecology and evolution of living organisms. The molecular revolution has co me in waves, so to speak, with three particularly important developments. The first concerns the establish- ment and widespread use of pro tein analysis. Microcomplement fixation and isozyme e1ectrophoresis were the techniques around which much of the genetic work in ecology and evolution were once based. The next wave started with the development of recombinant DNA technology and centered around the use of restriction fragment length polymor- phisms (RFLPs) and sequencing of DNAs cloned in bacteria. This technology was the first to actually examine and accumulate genetic information at the nucleotide level. The most recent wave of technology that we are currently experiencing is based on our ability to amplify DNA sequences enzymatically via the Polymerase Chain Reaction (PCR). Several techniques re1ated to PCR have been developed and used extensively in ecological and evolutionary studies.

Evolutionary ecology includes aspects of community structure, trophic interactions, life-history tactics, and reproductive modes, analyzed from an evolutionary perspective. Freshwater environments often impose spatial structure on populations, e.g. within large lakes or among habitat patches, facilitating genetic and phenotypic divergence. Traditionally, freshwater systems have featured prominently in ecological research and population biology.

This book brings together information on diverse freshwater taxa, with a mix of critical review, synthesis, and case studies. Using examples from bryozoans, rotifers, cladocerans, molluscs, teleosts and others, the authors cover current conceptual issues of evolutionary ecology in considerable depth.

The book can serve as a source of critically evaluated ideas, detailed case studies, and open problems in the field of evolutionary ecology. It is recommended for students and researchers in ecology, limnology, population biology, and evolutionary biology.