In APS, organism–environment coupling refers to the reciprocal relation through which organisms and environments mutually shape the conditions of biological persistence.
Living systems do not first exist independently and then interact with an external environment. Organism and environment become reciprocally specified through ongoing relations of activity, constraint, regulation, and viability.
This concept is developed more fully in the glossary entry on Coupling, which explains how coupling functions as a constitutive organisational relation across biological systems.