Definitions and feedback -WC Flashcards
what is a flow/transfer
a link between one store or component and another, along which something moves
what is a store
a part of the system where something is held for a period of time
what is an input
a point where something is added to the system
output definition
the point where something is removed from the system
what is the system boundary
the edge of the system, the line between one system and another
example of inputs in a pond system
precipitation
leaf fall during autumn
seeds carried by winds
processes within the pond system
photosynthesis
infiltration
transpiration
stored within the pond system
water
soil
plants
outputs within the pond system
evaporation
seed dispersal
water infiltrating into soil below
what are the main 3 types of systems
open, closed and isolated
what is an open system
where matter and energy can be transferred from the system across the boundary into the surrounding environment (most ecosystems are an example)
what is a closed system
these have transfers of energy both into and beyond the system boundary but not the transfer of matter (eg sediment cells)
what is an isolated system
have no interactions with anything outside the system boundary. no input or output of energy or matter
what is the most common type of system
open
what is dynamic equilibrium
when there is a balance between the inputs and outputs in a system
what is positive feedback
where the effects of an action (eg the increase of CO2) are amplified by subsequent knock-on effects
what is negative feedback
where the effects of an action are nullified by its subsequent knock-on effects
example of negative feedback (with the stages)
increased use of fossil fuels = increase in atmospheric CO2= global temperature increase = more plant growth= increased uptake of CO2= reduction in atmospheric CO2= reduced global temperatures
what are the 5 subsystems on earth
atmosphere lithosphere (geology) hydrosphere biosphere cryosphere
