Author Institution: Department of Zoology and Institute of Ecology, University of GeorgiaA systems theory of environment formulates causal interactions between things, including organisms, and their environments in terms of four system theoretical abstract objects. Creaons receive stimuli and implicitly create input environments. Genons react to received causes and generate potential output environments as effects. A holon represents the combined input-output model of an entity consisting of a creaon and a genon. An environ is a creaon and its corresponding input environment, or a genon and its related output environment. The theory is presented in terms of three propositions that: (1) recognize two distinct environments (input and output) associated with things, (2) establish things and their environments as units (environs) to be taken together, and (3) partition systems into input and output environs associated with intrasystem creaons and genons, respectively
