1. Introduction2. Ecosystems have Openness (Thermodynamic)3. Ecosystems have Ontic Openness4. Ecosystems have Connectivity5. Ecosystems as self-organizing Hierarchies6. Ecosystems have Directionality7. Ecosystems have Complex Dynamics (Growth and Development)8. Ecosystems have Complex Dynamics (Disturbance and Decay)9. Ecosystem Principles have Broad Explanatory Power in Ecology10. Ecosystem Principles have Ecological Applications11. Ecosystems carry important messages to Managers and Policy Makers12. Conclusion13. References