Natural systems Flashcards
inputs
when matter or energy is added to the system e.g. precipitation and photosynthesis.
outputs
when matter or energy leaves the system e.g. evaporation or combustion
stores
where matter or energy builds up e.g. ground water storage or sedimentary rock
flows
when matter or energy moves from one store to another e.g. infiltration and respiration
boundaries
the limits of a system. in a drainage basin system, the watershed is the boundary.
open systems
both energy and matter can leave or enter.
e.g. drainage basins are open because they have an input of precipitation and an output of river discharge.
closed systems
matter cant leave or enter but energy can.
e.g. the carbon cycle is a closed system because energy is inputted from the sun by photosynthesis but the amount of carbon will always stay the same.
dynamic equilibrium
a state of balance in a system between inputs and outputs. flows continue to happen, but in the same way at the same time so there is no overall change.
large, long term changes to a system can off-set balance, or create a new dynamic equilibrium.
positive feedback
a mechanism that amplifies the change in the inputs or outputs.
the system responds by increasing the effects of change, moving the system further from its previous state.
e.g.
temp rise —–> ice melts —–> less ice cover means less of the suns energy is reflected —–> less reflected = more absorbed —–> temp rise.
negative feedback
mechanisms counteract the change in the inputs or outputs. the system responds by decreasing the effects of the change, keeping the system closer to its previous state.
e.g.
C02 emitted —–> atmospheric C02 increases —–> plant increase growth —–> plants remove C02 —–> C02 reduces.
subsystems of the earth
the idea that the earth is made of subsystems which are interlinked by cycles. matter moves between them, the output of one system is the input of the next.
the earth is a cascading system.
