Thermal conditions@ air quality@ lighting@ noise@ ion concentration@ and crowding are important in designing structures for animals and plants. Thermal environment influences heat dissipation by animals and chemical process rates in plants. Lighting influences photoperiodism in animals and plants@ and photosynthesis and regulation in plants. Air quality@ noise@ ion concentrations@ and crowding can affect the health and/or productivity of animals or plants. This chapter summarizes the published results from various research projects and provides a concept of the physiological factors involved in controlling the environment.