the evolution of self-organising open systems. However, the principle has only been demonstrated in a few experiments and is not widely recognized in the scientific community. Ecosystem ecology and systems ecology For J. B. Hagen, the maximum power principle, and the stability principle could be easily translated into the language of homeostasis and cybernetics systems. Hagen claims that the feedback loops in ecosystems were, for Odum, analogous to the kinds of feedback loops diagrammed in electronic circuits and cybernetic systems. This approach represented the migration of cybernetic ideas into ecology and led to the formulation of systems ecology. In Odum's work these concepts form part of what Hagen called an, "ambitious and idiosyncratic attempt to create a universal science of systems". Macroscope Hagen identified the systems, thinking of Odum as a form of holistic thinking, who contrasted the holistic thinking of systems science with reductionistic microscopic thinking, and used the term macroscope to refer to the holistic view, which was a kind of "detail eliminator" allowing a simple diagram to be created. Microcosms Odum was a pioneer in his use of small closed and open ecosystems in classroom teaching, which were often constructed from fish tanks or bottles and have been called microcosms. His microcosm studies influenced the design of Biosphere 2. Ecological economics Ecological economics is an active field between economics and ecology with annual conferences, international societies, and an international journal. From 1956 to 1963, Odum worked as Director of the Marine Institute of the University of Texas. During this time Odum became aware of the interplay of ecological-energetic and economic forces. He therefore funded the research into the use of conventional economic approaches to quantify dollar values of ecological resources for recreational, treatment and other uses. This research calculated the potential value of primary production per bay surface area. For Hall the importance of Odum's work came through his integration of systems, ecology, and energy with economics, together with Odum's view that economics can be evaluated on objective terms such as energy rather than on a subjective, willingness to pay basis. Ecological engineering Ecological engineering is an emerging field of study between ecology and engineering concerned with the designing, monitoring and constructing of ecosystems. The term ecological engineering was first coined by Odum in 1962, before he worked at the University of Florida. Ecological engineering, he wrote, is "those cases where the energy supplied by man is