Systems:
- Inputs-when matter of or energy is added to the system
- Outputs-when matter or energy leaves the system
- Store- where matter or energy builds up
- Flows – when matter or energy moves from one store to another.
- Boundaries – the limits of a system,
- Open System: both energy & matter can enter and leave the system – there are inputs and outputs of both- E.g Drainage Basin
- Closed System: Matter cant enter or leave the system it can just cycle between stores, energy can enter and leave a closed system E.g Carbon Cycle
Feedbacks:
- Dynamic Equilibrium: if the inputs and the outputs of a system is balanced – flows and processes continue to happen but in the same ways at the same time – so no overall changes to the system
- Large and long term changes to the balance of inputs and outputs can cause a system to change and establish a new dynamic equilibrium and changes can trigger positive and negative feedback.
- Positive Feedback mechanisms amplify the change in inputs or outputs
- Systems respond by + the effects of the change, moving system further from previous state
- G: Temperature rises – ice melts – less of the suns energy is reflected – more is absorbed
- Negative Feedback mechanisms nulitify the change in the inputs or outputs
- Systems responds by – the effect of the change, keeping the system closer to previous state
- G CO2-Planst grow-absorb CO2- Less CO2
Subsystems of Earth: Changes that occur in one subsystem can affect what happens in the others.
- Cryosphere- all the parts of the earths systems where its cold enough for water to freeze.
- Sea Ice: frozen ocean water, less dense, floats
- Glaciers: Formed from compacted ice within mountain valleys
- Ice Caps: Sits on mountains and regional sized
- Ice sheets: Glacier ice that’s covers oceans only in Greenland and Antarctica
- Permafrost: Permanent frozen ground which acts as a source of methane when melted
- Thawing will result in 0.5OC extra climate change as dead organic matter held in upper layers decomposes
- Lithosphere- outermost part of the earth. It includes the crust and the upper parts of the mantle.
- g Limestone, Shale, Chalk
- Biosphere- living things are found. it includes all living parts of the earth – plants, animals, fungi etc.
- Hydrosphere – includes all the water on the earth. It may be in a liquid form (lakes and rivers) solid form (ice) or gas (water vapour stored in the atmosphere)
- Atmosphere- layer of gas between the earths surface and space, held in place in gravity.
- Earth is a cascading system- Matter and energy moves from one subsystem to another