Systems

Question 1

Define input

Answer 1

The addition of material or energy into a system.

E.g. precipitation, leaf fall or seeds carried by winds.

Question 2

Define output

Answer 2

The removal of material or energy from the system

Eg runoff, evaporation, seed dispersal

Question 3

Define store

Answer 3

The individual elements of a system where energy or material is stored.

Question 4

Define flow (transfer)

Answer 4

The relationship between the components that involves the movement of energy or mass.

Question 5

Define positive feedback.

Answer 5

A cyclical sequence of events that amplifies or increases change. It promotes environmental instability.

Question 6

Define negative feedback

Answer 6

A cyclical sequence of events that nullifies or dampens down the effects of a system. It promotes stability and a state of dynamic equilibrium.

Question 7

Define dynamic equilibrium.

Answer 7

A state of balance within a constantly changing system.

Question 8

Example of an input in a drainage basin

Answer 8

Precipitation

Question 9

Example of input in the woodland carbon cycle

Answer 9

Precipitation with dissolved CO2

Question 10

Example of an output in the drainage basin

Answer 10

Runoff

Question 11

Example of an output in the woodland carbon cycle

Answer 11

Dissolved carbon within runoff

Question 12

Example of energy in the drainage basin

Answer 12

Latent heat associated with changes within the water (eg condensation)

Question 13

Example of energy within woodland carbon cycle

Answer 13

The production of glucose through the process of photosynthesis

Question 14

Examples of stores within the drainage basin

Answer 14

Trees, puddles, soil

Question 15

Example of stores within the woodland carbon cycle

Answer 15

Trees, soil, rocks

Question 16

Examples of flows within a drainage basin

Answer 16

Infiltration, groundwater flow, evaporation

Question 17

Examples of flows within the woodland carbon cycle

Answer 17

Burning, absorption

Question 18

Example of positive feedback in a drainage basin

Answer 18

Thermal expansion and melting freshwater ice causes rising sea levels.
This can destabilise ice shelves, increasing the rate of calving.
This leads to an increase in melting, leading to a further sea level rise.

Question 19

Example of positive feedback in a woodland carbon cycle

Answer 19

Increased temperatures due to climate change causes a melting of permafrost.
Trapped greenhouse gases are therefore released.
This enhances the greenhouse effect further - causing a further increase in temperatures.

Question 20

Example of negative feedback in a drainage basin

Answer 20

Increased surface temperatures leads to an increase in evaporation from the oceans.
This leads to more cloud cover.
Clouds reflect radiation from the sun, resulting in a slight cooling of surface temperatures.

Question 21

Example of negative feedback in a woodland carbon cycle

Answer 21

Increased atmospheric CO2 leads to increased temperatures.
This promotes plant growth and the rate of photosynthesis.
In turn, this removes more CO2 from the air - which counteracts the rise in temperature.

Question 22

What is an isolated system?

Answer 22

These have no interactions with anything outside of the system boundary - they have no inputs or outputs.
Rare un nature, most common in controlled laboratory experiments.

Question 23

What’s an open system?

Answer 23

Where matter and energy can be transferred from the system, across the boundary and into the surrounding environment.
Eg ecosystems.

Question 24

What’s a closed system?

Answer 24

They have transfers of energy into and beyond the system boundary, but not the transfer of matter.

Question 25

On a global scale, the water and carbon cycles are _______ systems.

Answer 25

Closed - there are no inputs or outputs.

Question 26

On a local scale, the water and carbon cycles are ______ systems.

Answer 26

Open