Diagrams refer to the phenomena overtly represented, to analogous phenomena, and to previous pictures and their graphic conventions. The diagrams of ecologists Clarke, Hutchinson, and H.T. Odum reveal their search for physical analogies, building on the success of World War II science and the promise of cybernetics. H.T. Odum's energy circuit diagrams reveal also his aspirations for a universal and natural means of reducing complexity to guide the management of diverse ecological and social systems. Graphic conventions concerning framing and translation (...) of ecological processes onto the flat printed page facilitate Odum's ability to act as if ecological relations were decomposable into systems and could be managed by analysts external to the system. (shrink)