Unit 1.2 Systems Flashcards
What is a system?
A system is a set of interactive, intercommunicating, or interdependent parts, that constitute a whole.
What is a systems approach?
A systems approach is a holistic way of visualising a complex set of interactions which can be applied to ecological or societal situations.
What are emergent properties?
Emergent properties are collective properties resulting from the interactions of parts of larger systems.
What does a system diagram consist of?
A system consists of storages and flows. Storages are where matter or energy is kept. They are represented as a rectangular box.
Flows are the inputs and outputs of energy and matter. They are represented as arrows, facing the flow’s direction.
What can flows be?
Flows are processes that can be either transfers (change of location), or transformations (change in state of matter, or change in energy).
What is an open system?
An open system exchanges both matter and energy with its surrounding environment. Examples are: the human body, trees, etc.
What is a closed system?
A closed system exchanges only energy with its surrounding environment. Examples are: Biosphere 2, Earth, thermos, water cycle.
What is the Gaia hypothesis?
Scientist James Lovelock compares the Earth to a living organism in which feedback mechanisms maintain equilibrium. All parts of the Earth form a complex interacting system, maintaining homeostasis.
What is Feedback?
Feedback refers to the return of the output, or part of it, as input thus affecting successive outputs.
What is a Negative feedback loop?
A Negative feedback loop occurs when the output of a process inhibits or reverses the operation of the same process in such a way as to reduce change. They are stabilising forces within systems as they counteract deviation.
Examples: Lynx-hare population, Temperature regulation, homeostasis,
What is a steady-state equilibrium?
The property of most natural open systems to remain stable despite constant energy and matter inputs and outputs. Short-term oscillations occur, but it retains its original state in the long term.
What is the difference between a stable and unstable equilibrium?
If a system returns to the original equilibrium after a disturbance, it is stable (negative feedback loops).
If a system doesn’t return to the original and instead reaches a new equilibrium after a disturbance, it is unstable (positive feedback loops).
What is a positive feedback loop?
A positive feedback loops occurs when a disturbance leads to an amplification of that disturbance, destabilising the system and driving it away from its equilibrium.
Examples: global warming, population growth, ice thawing, cycle of poverty
What is a tipping point?
A tipping point is a critical threshold where even a small change can can cause a disproportionately large response in the overall system. They are a result of positive feedback loops, where a new equilibrium is adopted.
Examples: climate change,
