the ecological vantage point of populations interacting with their environment.Anatomy, systematics, biochemistry, and even molecular biology becomemore fully focused when utilized in analyses of ecosystems.Onamore practical level, the study of existing ecosystems has vitalized the conservation movement and enhanced the active effort to
maintain ecosystems or even individual species of plants or animals threatened with extinction. Apossible weakness of ecology stems from the broad spectrum of its concerns—it tends to be diffuse. Individual ecologists do focus on particular aspects of communities or the physical environment but the novice might find the field daunting by its very breadth. In its descriptive phase, that breadth was more easily handled.The recentemphasis on experimentation tends to encourage a specialization within the field but experimentation introduces another problem. With experimentation, controlled conditions may not be readily obtained in a field situation. Ecosystems can be studied froma passive approach, in which the experimenter merely observes such phenomena as energy flow, diversity of species, etc., but more ambitious attempts to establish an ecological science require interventions that may be difficult to isolate and control. Some success has been achieved, particularly where clear boundaries to a habitat exist, such as on islands
