1 - Natural Systems Flashcards
What is an input?
When matter or energy is added to the system.
What is an output?
When matter or energy leaves the system.
What is a store (or component)?
Where matter or energy builds up.
What is a flow (or transfer)?
When matter or energy moves from one store to another.
What are boundaries?
The limits of the system.
What is an open system? Give an example.
Both energy and matter CAN enter and leave an open system.
e.g Drainage basins: energy from the Sun enters and leaves and water is input as precipitation and is output as river discharge into the sea.
What is a closed system? Give an example.
Matter CAN’T enter or leave (is only cycled between stores)
Energy CAN enter or leave (be an input or output)
e.g the Carbon Cycle: energy is input (photosynthesis from the sun) and output (respiration), but the amount of carbon on Earth stays the same because there are no inputs or outputs of matter.
When is a system in equilibrium?
When the inputs and outputs of a system are balanced. Flows and processes happen but there are no overall changes to the system.
When is a system in dynamic equilibrium?
Variations in the inputs and outputs of a system (e.g variations of precipitation in a drainage basin) are small so remain balanced on average.
What can changes in a system trigger?
Positive or negative feedback.
Define positive feedback.
It amplifies the change in the inputs or outputs,
…meaning 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.
Temps rise, ice melts, less of Sun’s energy is reflected, more of Sun’s energy is absorbed by the sea and Earth, temp rise…
Define negative feedback.
It nullifies and counteracts the change in the inputs or outputs,
…meaning the system responds by decreasing the effects of change,
…keeping the system closer to its previous state.
Give an example of negative feedback.
Large amounts of CO2 emitted, CO2 in atmosphere increases, extra CO2 causes plants to increase growth, plants remove and store more CO2 from the atmosphere, amount of CO2 in atmosphere reduces!
If Earth is one big closed system, name the 5 smaller subsystems on Earth and how they are interlinked.
Cryosphere
Lithosphere
Biosphere
Hydrosphere
Atmosphere
Interlinked by cycles and processes that keep the Earth system running e.g water cycle and carbon cycle! Matter and energy move between the subsystems - the output of one cycle is the input of the next cycle and changes in one subsystem create a domino effect of changes in the next subsystems.
