Earth's Life Support Systems

Question 1

Water

Answer 1

Provides a medium for organic molecules to mix and form more complex structures

Question 2

Open systems

Answer 2

• Smaller scale
• Both material/matter and the sun’s energy cross the systems boundaries
• Inputs and outputs

Question 3

Closed systems

Answer 3

• Global scale
• driven by the sun’s energy which is external to the earth
• only energy crosses the systems boundaries
• no inputs and outputs

Question 4

Precipitation

Answer 4

• any source of moisture reaching the ground

- e.g. Rain, sleet, hail, snow etc.

Question 5

Evapotranspiration

Answer 5

The water loss to the atmosphere from the evaporation of the ground surface and the transpiration of ground water by plants through their leaves.

Question 6

Interception

Answer 6

• natural flood defence
• precipitation being prevented from reaching the surface by trees or grass or plants etc.
• the precipitation could also land on buildings and concrete before it reaches the soil
• summer -> more leaves = more interception
• winter -> less leaves = less interception

Question 7

Overland flow (Surface runoff)

Answer 7

• Water flowing across the surface of the land, whether in a channel or over the land.

( water flowing on top of the ground)

• Due to saturation/impermeable rocks/intensity (heavy rainfall)/frozen ground.
• cannot infiltrate

Question 8

Infiltration

Answer 8

• The downward movement of water from the land surface into soil or porous rock.
• Infiltration happens before percolation

Question 9

Throughflow

Answer 9

• When water travels through the soil towards a river or the sea.

Question 10

Percolation

Answer 10

• The downward movement of water from the soil into the rock.

Question 11

Groundwater flow

Answer 11

• The movement of water through the fractures of rock formations.

Question 12

Dynamic equilibrium

Answer 12

• State of balance attained by maintaining equal rates of input and withdrawal from a system.

Input = output

E.g.
The rate of water that is leaving the system equals the rate of water that enters the cycle.

Question 13

Surface storage

Answer 13

• The part of precipitation retained on ground surface.

- The total volume of water held on the Earth surface in lakes, ponds and puddles.

Question 14

Water table

Answer 14

The upper level of saturated soil where no more water can be absorbed.

Question 15

Soil moisture

Answer 15

• Water held in the soil layer.