System Concepts and Feedback Loops

Flashcards covering key concepts of systems, including inputs, outputs, energy, stores, flows, positive feedback, and negative feedback, with examples from drainage basins and woodland carbon cycles.

What is defined as material or energy moving into a system from outside?

Input

Give an example of an input in a drainage basin.

Precipitation

Give an example of an input in a woodland carbon cycle.

Precipitation with dissolved CO2

What is defined as material or energy moving from a system to the outside?

Output

Give an example of an output in a drainage basin.

Runoff

Give an example of an output in a woodland carbon cycle.

Dissolved carbon within runoff

What is meant by 'energy' in the context of a system?

Power or driving force

Give an example of energy in a drainage basin.

Latent heat associated with changes in the state of water

Give an example of energy in a woodland carbon cycle.

Production of glucose through the process of photosynthesis

What are 'stores/components' in a system?

The individual elements or parts of a system

Give an example of stores/components in a drainage basin.

Trees, puddles, soil

Give an example of stores/components in a woodland carbon cycle.

Trees, soil, and rocks

What are 'flows/transfers' in a system?

The links or relationships between the components

Give examples of flows/transfers in a drainage basin.

Infiltration, groundwater flow, evaporation

Give examples of flows/transfers in a woodland carbon cycle.

Burning, absorption

What is positive feedback?

A cyclical sequence of events that amplifies or increases change, worsening outputs and promoting environmental instability.

Provide an example of positive feedback related to climate change.

Increased temperatures cause melting of permafrost, releasing trapped greenhouse gases, enhancing the greenhouse effect, and raising temperatures further.

What is negative feedback?

A cyclical sequence of events that reduce or neutralise the effects of a system, promoting stability and a state of dynamic equilibrium.

Provide an example of negative feedback in the woodland carbon cycle.

Increased atmospheric CO₂ leads to increased temperatures, promoting plant growth and rates of photosynthesis, which removes more CO₂ from the air, counteracting the rise in temperature.