WATER AND CARBON CYCLE - Natural Systems Flashcards
What is a system?
An assemblage of interrelated parts that work together by way of some driving force. A set of steps that occur to make something happen.
Elements
Things that make up the system.
Flow/transfer
A link between one store or component and another, along which something moves.
System Boundary
The edge of the system; the interface (or line) between one system and another.
Relationships
Descriptions of how the various elements work together to carry out some sort of process.
Store/component
A part of the system where something is held for a period of time.
Attributes
The characteristics of the elements (e.g. hot/cold).
Input
A point where something is added to the system.
Output
A point where something is removed from the system.
Types of systems
Closed, open and isolated.
Open system and example
A system that transfers both matter and energy across its boundary to the surrounding environment.
E.g. A drainage basin - energy from sun enters and leaves system. Water is input as precipitation, and output as river discharge into the sea.
Closed system and example
A system that transfers energy, but no matter, across its boundary to the surrounding environment.
E.g. The carbon cycle is a closed system - energy is input (from sun by photosynthesis) and output (by respiration), but the amount of carbon on earth stays the same as no inputs and outputs of matter.
Isolated system and example
A system that has no interactions beyond its boundary layer.
E.g. The whole universe
System in equilibrium
When the inputs and outputs of a system are balanced. Flows and processes occur but no overall changes to system.
System in dynamic equilibrium
Lots of small variations in inputs and outputs of a system. Variation quite small so inputs and outputs remain about balanced on average.
What do large, long term changes to balance of inputs and outputs of a system cause?
The system to change and establish a new dynamic equilibrium.
What can changes in a system trigger?
Positive or negative feedback.
Positive feedback
Occurs where effects of an action are amplified by changes to the inputs/ outputs / processes. System responds by increasing effects of change, moving system even further from its previous state.
Negative feedback
Occurs where effects of an action are nullified by changes to the inputs/ outputs/ processes. Means system responds by decreasing the effects of the change, keeping system closer to its previous state.
Example of positive feedback
Global temperature rise —> Ice covering cold parts of earth melts due to higher temperatures —> Less ice cover means less of the sun’s energy is reflected —> Means more of the Sun’s energy is absorbed by the earth —> GLOBAL TEMPERATURE RISE
Example of negative feedback
Large amounts of CO2 emitted —> CO2 in atmosphere increases —> Extra CO2 causes plant growth to increase —> Plants remove and store more CO2 from atmosphere —> Amounts of CO2 in atmosphere reduces
What type of system is the Earth
Closed system
Energy input from sun and output to space but no mater input or output.
What are the five subsystems that make up Earth?
Cryosphere, Lithosphere, Biosphere, Hydrosphere, Atmosphere
Cryosphere
Includes all the parts of the Earth system where it’s cold enough for water to freeze (ice).
Lithosphere
The outermost part of the Earth. Includes the crust and the upper parts of the mantle. Geology.
Biosphere
The parts of Earth’s system where living things are found. Includes all the living parts of Earth - plants, animals, birds, fungi, insects, bacteria etc. Organic Life.
Hydrosphere
Includes all the water on Earth. May be liquid form (e.g. lakes and rivers), solid form (ice stored in the cryosphere) or gas form (water vapour stored in the atmosphere). Can be saline (salty) or fresh. Water.
Atmosphere
The layer of gas between the Earth’s surface and space. Held in place by gravity. Air.
All the subsystems of Earth are…
Interlinked by the cycles and processes that keep the Earth system as a whole running as normal (e.g. the carbon and water cycles).
What moves between the subsystems?
Matter and energy. The output of one is input of next.
What is the Earth system with the interlocking subsystems refered to as?
A cascading system.
What do changes in one subsystem do? What do the interlocking relationships have a profound effect on?
Affect what happens in other subsystem. On the Earth’s climate.
