Systems Analysis Mr. Clark Bethpage HS AP Environmental Science

Systems Models and Behaviors of Systems System Regulation

Systems A system is a set of components or parts that function as a whole. An open system has no boundaries. A closed system has boundaries. Systems respond to inputs and have outputs.

Models and Behaviors of Systems Inputs (cause) Throughputs or Flows Stores Outputs (effect)

System Regulation Feedback Negative feedback Positive feedback Time delay Synergy

Negative Feedback Negative feedback is stabilizing. A thermostat is a simple example of negative feedback.

Positive Feedback Positive feedback is destabilizing. Positive feedback can potentially go on indefinitely. The runaway greenhouse effect is an example of a positive feedback scenario.

Time Delay Relationships between input and output of systems may be non-linear and involve time delays.

Non-Linear Change Exponential growth Rule of 70

Synergy Synergistic effects are outputs that are greater than the sum of the inputs due to an interaction that amplifies the effect.

Systems Inputs (from environment) Throughputs (rates of flow) Outputs (to environment) Human Body (inputs may be stored for different lengths of time) Energy Information Matter Heat Ideas and actions Waste and pollution

Environmental Unity The principle of environmental unity simply stated says everything effects everything else. It emphasizes linkages amongst environmental systems.

Uniformitarianism The principle of uniformitarianism states that future environmental conditions can be predicted based on the present and the past. The past is the key to the future.

Gaia Hypothesis Life on Earth through a complex system of negative and positive feedback control regulates the planetary environment to sustain life.