ECOSYSTEMS AND THE BIOSPHERE AS COMPLEX ADAPTIVE SYSTEMS

Ecosystems are prototypical examples of complex adaptive systems, in w hich patterns at higher levels emerge from localized interactions and selection processes acting at lower levels. An essential aspect of suc h systems is nonlinearity, leading to historical dependency and multip le possible outcomes of dynamics. Given this, it is essential to deter mine the degree to which system features are determined by environment al conditions, and the degree to which they are the result of self-org anization. Furthermore, given the multiple levels at which dynamics be come apparent and at which selection can act, central issues relate to how evolution shapes ecosystems properties, and whether ecosystems be come buffered to changes (more resilient) over their ecological and ev olutionary development or proceed to critical states and the edge of c haos. Key words: Gaia; self-organization; complex adaptive system; hom eostasis; nonlinearity; keystone species; functional group.