What is a flow/transfer?
A form of linkage between one store/component and another that involves movement of energy or mass.
Input
The addition of matter and/or energy into a system.
Store/component
A part of the system where energy/mass is stored or transformed.
System
A set of interrelated components working together towards some kind of process.
What are the 3 types of property?
Elements, attributes and relationships
What are elements?
Things that make up the system of interest.
What are attributes?
The perceived characteristics of the elements.
What are relationships?
Descriptions of how the various elements and their attributes work together to carry out some kind of process.
What are the 4 key features of systems?
Their structure lies within a boundary.
Generalisations of reality.
Function by having inputs and outputs of material which are processed within the components causing it to change in some way.
Involve the flow of material between components.
What is the advantage of generalisations of reality in regards to systems?
They remove incidental detail that obscures fundamental relationships.
What are the three ways in which systems can be classified?
Isolated
Closed
Open
What is meant by an isolated system?
Have no interaction with anything outside of the system boundary. No inputs or outputs.
Give an example of an isolated system
A laboratory experiment
What is a closed system?
Has a transfer of energy both into and beyond the system boundary but not transfer of matter.
What is an open system?
Where matter and energy can be transferred from the system across the boundary into the surrounding environment.
Give an example of an open system
An ecosystem
What is dynamic equilibrium?
A balance between inputs and outputs
What does dynamic equilibrium mean for the stores?
They stay the same
When does feedback occur?
When one of the elements in a system changes, without a corresponding change, upsetting the equilibrium.
What is positive feedback?
Where the effects of an action are amplified by knock-on or secondary effects.
What is negative feedback?
Where the effects of an action are nullified by its subsequent knock-on effects.
What type of system is the Earth?
A closed system
What are the 4 major subsystems?
Atmosphere
Lithosphere
Hydrosphere
Biosphere
What is a cascading system?
An open system that forms part of a chain.
Give an example of a cascading system
The atmosphere, hydrosphere, lithosphere and biosphere.
What do the interlocking relationships between the lithosphere, hydrosphere, biosphere and atmosphere have an effect on?
The Earth’s climate and climate change.
