Topic 1 - Systems and Models - key words

Question	Answer
System	an assembly of parts & their relationships which together constitute a whole.
transfers	change in location with no change in state
transformations	formation of new products or a change in state
detritus	dead material
open systems	exchange in matter and energy (e.g. - ecosystems)
closed systems	exchange only energy (e.g Earth)
Isolated systems	do not exchange anything
1st law of Thermodynamics	energy entering an ecosystem equals the energy leaving it or stored - energy can neither be created or destroyed
2nd law of thermodynamics	energy is gradually transformed into heat energy due to inefficient transfer thus increasing entropy
steady state equilibrium	constant inputs and outputs but the system generally stays the same - e.g Climax ecosystem
stable equilibrium	disturbance leads to a return to the original equilibrium
unstable equilibrium	moves to a new equilibrium after a disturbance
feedback	is when a part of the output returns to a system as input
positive feedback	this is feedback that increases change : promotes deviation from and equilibrium
negative feedback	feedback that tends to counteract any deviation from equilibrium (e.g predator and prey)
Model	a simplified version of a system - it shows flows & storages as well as structures and workings
biomagnification	increase of concentration with increase in tropic level

Resource summary

	Created by Sarah-Karolina V about 11 years ago