Understanding the present requires insights into the past. We will therefore briefly describe the development of ecology and ecosystem knowledge. In particular, we will follow how terrestrial ecosystem ecology has grown from early primitive ideas about Nature and how a natural science perspective gradually has become the foundation for investigating Nature and its function. From early ecology there has been a steady development, eventually leading to the introduction of the ecosystem concept. This development towards an independent discipline is, however, dependent on a number of basic disciplines. We see a number of ecological directions dealing with basic understanding, as well as applied questions, such as worldwide production of food and maintaining the ecosystems in a sustainable way. Major actors or profiles and their impact on the discipline are presented.