The term ecosystem has been widely used, often in a confusing manner, since it was first coined some 50 years ago. This book uses the term in the way it was originally defined, as a means of describing the biota which live together as a social unit and also the inorganic and dead parts of the system. Topics covered include arctic, desert, marine and tropical ecosystems, their dynamics and structure, economics, evolution and ecological phenomena. The book will be of particular value to biologists, ecologists and planners to assist them in widening and deepening their knowledge of natural ecosystems which will in turn help them to understand the processes inherent in man-made ecosystems.