System:
A set of
components that
1) function and interact in some regular and theoretically
predictable manner
2) can be isolated for the purposes of observation and study.
Components are:
- Inputs
- Flows or throughputs
- Stores or storage areas
- Outputs
Why are models of
complex systems Useful?
- they give us improved perceptions and
predictions
- they significantly shorten the time needed to
gather and interpret data
How do feedback
loops effect systems?
Feedback loop:
- occurs when one change leads to some other
change, which eventually either reinforces or slows the original change
- ex: Aluminum Cans
- can be either positive or negative
- runaway cycle
- change encourages change further in the same
direction
- vicious circle
- can destabilize a system
- ex: projected global warming or bank account w/
interest
- one change leads to a lessening of that change
- ex: body temp
- desirable because it stabilizes a system
homeostasis:
- maintenance of a favorable internal condition
despite fluctuations of external conditions
- contains one or more negative feedback loops to
maintain system
- most systems contain both
The Tragedy of
Easter Island:
What kind of
system did it have?
positive feedback loops:
o abundant trees led to more births
negative feedback loops:
o more births led to more usage led to more deaths