Natural systems Flashcards
What are systems made up of?
- Stores
- Flows
- Boundries
- Inputs
- Outputs
What are inputs?
When matter (a physical substance like water or carbon) is added to a system.
What are outputs?
When matter or energy leaves a system.
What are stores?
Where matter or energy builds up.
What are flows/transfers?
When matter or energy moves from one store to another.
What are boundries?
The limits of a system.
How is a drainage basin an example of a system?
- Water enters the system as rain (input).
- The systems watershed is the boundry.
- Some of the water is stored in soil + vegetation.
- Water travels from the drainage baisin to the river and down the river (flow).
- Water leaves the system where the river meets the sea (output).
What are the different types of systems?
- Open
- Closed
What can open systems have?
Energy and matter can enter and leave an open system and there are inputs and outputs of both.
What is an example of an open system?
Drainage baisins as energy from the sun enters and leaves the system, the water is the input as precipitation and output is the river discharge into the sea.
What are closed systems?
When energy inputs = outputs.
What happens to matter in closed systems?
It cycles between stores as matter (physical substance such as water/carbon) can’t enter of leave a closed system.
What happens to energy in closed systems?
Energy can enter and leave a closed system and can be input or output.
What is an example of a closed system?
The carbon cycle is a closed system as energy is input (eg, the sun through photosynthesis) and output (eg, by respiration) but the amount of carbon on the earth stays the same as there are no inputs or outputs of matter.
What does it mean for a system to be in equilibrium?
Inputs = Outputs despite changing conditions.
Flows and processes can continue to happen but in the same way so there is no overall changes to the system.
How are systems affected by feedback?
- If the inputs and outputs of a system are balanced the system is in equilibrium.
- But within systems there are small variations in the inputs and outputs of systems (such as the amount of precipitation entering a river) but they tend to be very small so the inputs/outputs remain balanced. - This means the system is in dynamic equilibrium.
- Large, long term changes to the balance of inputs and outputs can cause the system to change and establish a new dynamic equilibrium.
What happens if there are changes within a system?
A positive or negative feedback may be triggered.
What does positive feedback do?
Amplify the change in inputs or outputs which means the system responds by increasing the effects of the change which moves the system moves further away it’s previous state.
What is an example of a positive feedback?
- Temperatures rise
- Ice covering the cold parts of earth melts as there are higher temperatures
- Less ice cover so less of the Sun’s energy is reflected
- Due to less energy being reflected more heat is absorbed by the earth.
What does negative feeback do?
They counteract the change in the inputs or outputs so the system responds through decreasing the effects of change and thus keeping the sytem closer to dynamic equilibrium.
What is an example of negative feedback?
- Large amount of CO2 emitted
- CO2 increases in the atmosphere
- Extra CO2 causes plants to grow
- Plants remove and store CO2 through photosynthesis
- Amount of CO2 in atmosphere decreases.
What type of system is the earth?
The earth can be seen as a closed system as energy is an input from the sun and then output to space but matter is not input or output to space. The earth is broken down into subsytems to explain further systems.
What are the subsytems in earth?
- Cyrosphere
- Lithosphere
- Biosphere
- Hydrosphere
- Atmosphere
What is the cyrosphere?
The cyrosphere includes all parts of the Earth system where it’s cold enough for water to freeze such as glacial landscapes.
