Natural systems

• Systems play an important role in physical geography as we try to simplify the complexity of our world so that we can understand it.
• What are systems?

  • Systems models show us the components of an aspect of geography and how these components (or stores) are linked through flows (or transfers).
  • Systems are generalised and exist within a certain boundary. They involve energy and/or matter flowing between components.
• Types of systems

  • An isolated system has no inputs or outputs and is rare in nature.
  • A closed system has inputs and outputs of energy, but not matter i.e. the water or carbon cycle.
  • An open system has inputs and outputs of both energy and matter i.e. the drainage basin system.
• • A system is in a state of dynamic equilibrium if the inputs and outputs are balanced.
  • If an element of the system changes the equilibrium will be upset; this is called feedback.
• • Negative feedback stabilises the system, allowing it to maintain its dynamic equilibrium.
  • Positive feedback means that the system experiences further change, continuing the disruption to the equilibrium.