Ecosystems are open systems, they receive solar energy and other materials from outside the ecosystem and migration of animals is also witnessed. I read Physics uptil class XII and have done a bit of research on google books and have come across these three books: 1.Towards a Thermodynamic Theory for Ecological Systems, pg-41 2.Thermodynamics of Non-Equilibrium Processes for Chemists, pg-9 3.Ecosystem Ecology, pg-35 P.S. I couldn't come up with anything statement. I'm not sure if I posted on the right sub-forum. Let me know if this is suitable to other sub-forums and tell me why do you think so.