You will gain insight into communities and ecosystems from a new perspective: system theory. This is a field in ecology which was not introduced before in the programme; the founder of the field was E. Odum. As indicated by the term, ecosystems are systems, similar to electrical systems, pneumatic systems, hydraulic systems, etc. All systems share common components and common functional characteristics, and this principle can be used in ecology to explain the dynamics of ecosystems over time (e.g. the temporal variation of the productivity of plankton in an estuary, the fluctuations of the population sizes in a complex foodweb, etc.). Universal components in systems are, among others, stocks (reservoirs) which are connected by fluxes. Feedbacks between components lead to stability or instability. System thinking is acquired through modelling exercises on ecosystem dynamics, using a simple model environment which every student can learn in a one-hour training session.