system

Any set of interrelated parts. A system can consist entirely of abstract ideas, but geographers prefer to use the concept in such fields as ecology, hydrology, and geomorphology. An open system allows mass and energy to circulate into and out of it; a closed system gives and receives energy but not mass.

A system deals with inputs, throughput, and outputs. Systems usually have a negative feedback, i.e. a redress of balance such that a kind of equilibrium is maintained. An example of this is the performance of a hillslope: increased mass movement downslope leads to decreased stream erosion at the base of the slope. As applied to geomorphology, a systems analysis is a ‘way of viewing complex geomorphological systems as the product of the storage, throughput, input and output of energy and mass’ (Harrison, Geography 84).

Systems may be studied at all scales and it should be noted that each system is part of a larger system. Thus, an oak-leaf system is part of an oak-tree system which is part of an oak-wood system…and so on. It is difficult to establish the boundaries of a system. In this latter example, we must decide where an oak-wood system begins and ends.

In a cascading system, a series of small sub-systems are linked from one system to another.