1.1.1 Systems in physical geography Flashcards
What are systems?
A set of interrelated components working towards a process, which allows us to understand how certain processes work.
What are the four components that systems have?
- Inputs
- Outputs
- Flows
- Stores
Types of systems
- Isolated
- Closed
- Open
Elements
Things that make up the system.
Attributes
The perceived characteristics of the system.
Relationships
How the various elements (and their attributes) work together to carry out a process.
Inputs
When matter or energy enters the system.
Outputs
When matter or energy leaves the system.
Stores
Where matter or energy builds up.
Flows (transfers)
When matter or energy moves from one store to another.
Boundaries
The limits of the system.
Give an example of a system (drainage basin)
Water enters as rain (input). The system’s watershed is the boundary. Some water is stored in the soil and vegetation. Water travels from the drainage basin to the river and then down the river (flows). It leaves the system where the river meets the sea (output).
Open system
Where energy and matter can be transferred from the system and into/beyond the surrounding environment.
Closed system
Where only energy transfers into and out of the system. They have no transfer of matter.
Isolated system
No inputs or outputs and have no interaction with anything outside of the system boundary – Not found in nature.
Give an example of a closed system
The carbon cycle is a closed system – energy is input (e.g. through photosynthesis) and output (e.g. respiration), but the amount of energy on Earth stays the same because there are no inputs or outputs of matter.
Give an example of an open system
Drainage basins are open systems as energy from the Sun enters are leaves the system. Water is an input as precipitation and an output as river discharge into the sea.
What is dynamic equilibrium?
Where inputs and outputs of a system are balanced - flows and processes continue to happen, but in the same way at all times so there are no overall changes to the system.
Positive feedback
Positive feedback mechanisms amplify the change in the inputs of outputs.
This means the system responds by increasing the effects of the change, moving the system even further from its previous state.
Give an example of positive feedback
Give an example of negative feedback
Albedo effect
A positive feedback climate process where a change in the area of ice caps, glaciers and sea ice alters the albedo and surface temperature of a planet. Warming tends to decrease ice cover and hence decrease the albedo, increasing the amount of solar energy absorbed and leading to more warming.
The Earth as a system
The Earth can be seen as a closed system – energy is input from the Sun and output to space, but matter is not input or output to space.
What are the subsystems which the earth is broken down into?
- Cryosphere
- Lithosphere
- Biosphere
- Hydrosphere
- Atmosphere
Cryosphere
All the parts of the Earth’s system where it’s cold enough for water to freeze. For example, glacial landscapes.
Lithosphere
The outermost part of the Earth. It includes the crust and upper parts of the mantle.
Biosphere
The biosphere is the part of the Earth’s systems where living things are found. It includes all the living parts of the Earth – plants, animals, birds, fungi, insects, bacteria, etc.
Hydrosphere
All the water on earth. It may be in liquid form (e.g. lakes or rivers), solid form (ice stored in cryosphere) or gas form (e.g. water vapour in the atmosphere). It can be saline (salty) or fresh.
Atmosphere
The layer of gas between the Earth’s surface and space, held in place by gravity.
Relationship between the subsystems
- These subsystems are interlinked by key systems such as the water cycle and carbon cycle.
- Matter (e.g. water and carbon) and energy move between subsystems.
- Changes that occur in one subsystem can affect what happens in others.
- Earth is thought to be a “cascading system” as energy and matter move from one subsystem to the next.
