Geography OCR A Level: Topic 1.2 - Earth's Life Support Systems

Question 1

3 importances of water

Answer 1

• key to understanding the evolution of life on earth as it provides a medium that allows organic molecules to mix and form more complex structures
• global patterns of weather and precipitation are dictated by the movement, quantity, and temperature of the water, both in the ocean and in the atmosphere
• water vapour a greenhouse gas absorbs radiation and due to this, the planet is 15 degrees warmer than it should be

Question 2

uses of water for humans

Answer 2

• 2/3s of agriculture use
• 1/5 of industry use
• 1/10 of domestic use
• strong hydrogen bonding in water it cannot be compressed therefore it is good at supporting organisms

Question 3

uses of water for flora and fauna

Answer 3

plant growth
flooding rivers carries nutrients to floodplains
goes through the soil filtering out any pollutants

Question 4

4 importances of carbon

Answer 4

building blocks of life
basis of world economy - fossil fuels, plastic and building materials
makes up CO2 which regulates global climate
versatile as it is highly reactive so can combine with many elements to produce a variety of compounds

Question 5

uses of carbon in natural world

Answer 5

present in chlorophyll which traps solar energy and this helps to form carbohydrates

Question 6

uses of carbon in humans

Answer 6

large scale exploration of fossil fuels has provided energy for industrial development

Question 7

What is a open system?

Answer 7

energy and matter are exchanged with the surroundings e.g. human processes

Question 8

What is a closed system

Answer 8

A system where neither matter nor energy can enter or leave e.g. putting a lid on the frying pan

Question 9

are carbon and water cycles open or closed

Answer 9

closed

Question 10

List the four features of a water and carbon cycle

Answer 10

atmosphere, oceans, land and biosphere (where all parts of earth exist e.g. rock,water, air and the rest of the ecosystem)

Question 11

On smaller scales though like a drainage basin in the water cycle and ocean in the carbon cycle they are

Answer 11

open

Question 12

What are inputs?

Answer 12

elements that added to/removed from a system, either energy or material

Question 13

what are stores

Answer 13

places that material is held for a period of time

Question 14

what are fluxes

Answer 14

measurements of the rate of flow of material between stores

Question 15

what are processes

Answer 15

physical mechanisms which drive the flux of material between stores

Question 16

what are transfers

Answer 16

routes that material and energy take as they move between stores

Question 17

what happens to animals organic matter

Answer 17

converted into carbon rich sedimentary rock due to heat and pressure

Question 18

what is a carbon sink

Answer 18

A place where carbon is stored

Question 19

examples of carbon sinks (x5)

Answer 19

limestone and deep ocean sediment are the biggest carbon stores
storage in plants, atmosphere and soil is small

Question 20

4 stages of the carbon cycle

Answer 20

1. Photosynthesis is what plants do to create glucose the equation is:
   6 CO2 + 12 H2O → C6H12O6 + 6 O2 + 6 H2O. This means carbon is used. Plants use the chemical energy for processes such as growth where they release CO2 back into the atmosphere
2. Respiration is carried out by animals and plants to release energy from glucose, the equation is:
   C6H12O6 + 6O2 → 6CO2 + 6H2O . This means carbon is produced.
3. Decomposition: Decomposer organisms like fungi and bacteria breakdown dead organic matter extracting energy and releasing CO2 and minerals to the soil.
4. Combustion is burning, if something with carbon is burnt it will release it into the atmosphere, e.g. a tree, fossil fuel.

Question 21

What is carbon sequestration

Answer 21

a natural or artificial process by which carbon dioxide is removed from the atmosphere and held in solid or liquid form.

Question 22

Physical inorganic pump: Carbon Sequestration

Answer 22

involves the mixing of surface and deep ocean waters by vertical currents which creates an even distribution of carbon.
initially CO2 diffuses from the atmosphere to the ocean.
surface ocean currents transport this water polewards where it cools becoming denser thus sinks (downwelling)

Question 23

Trees in rainforests store

Answer 23

lots of carbon

Question 24

If there are lower temperatures air holds

Answer 24

less water

Question 25

evaporation is dependent on two things

Answer 25

the temperature

water bearing capacity of air

Question 26

What is transpiration?

Answer 26

The loss of water from a plant

Question 27

4 What affects transpiration?

Answer 27

temperature - high so more latent heat of vaporisation thus encourages evaporation
humidity
light
wind

Question 28

What is latent heat?

Answer 28

the heat required to convert a solid into a liquid or vapour, or a liquid into a vapour, without change of temperature.

Question 29

When does condensation occur?

Answer 29

when the air in the atmosphere reaches its dew point

at this point the air is saturated with water

Question 30

why does air reach a saturation point (x2)

Answer 30

the air cools down (can’t hold as much water)

more water is added to the atmosphere

Question 31

Clould formation (5 steps)

Answer 31

1) A parcel of air at the earth’s surface is warmed so it expands decreasing its density. Therefore it is more buoyant than surrounding air so rises. Now unstable.
2) Increasing in height the parcel experiences decreasing pressures so expands even more and results in it cooling. Adiabatic cooling
3) Before the parcel reaches its dew point it will cool at 10 degrees/100m. Dry adiabatic lapse rate
4) As soon as it reaches its dew point, condensation begins and air now cools at 6.5 degrees/100m. This is saturated adiabatic lapse rate
5) The real vertical temperature profile of an air mass is known as the environmental lapse rate

Question 32

Bergeron Process

Answer 32

Hot air rises so the water vapour on the ground will continue to rise. As water vapour rises in the atmosphere it becomes supercooled water vapour droplets. It continues to rise. Within a pocket of air higher up there might be some frozen nuclei, along with the supercooled water droplets. If the supercooled water droplets don’t touch the frozen nucleii then it will continue to rise and freeze at much lower temperatures. At -40C Ice crystals form. The Ice crystals might become too heavy and drop. If saturation point is reached the ice crystals can hold no more water vapour at its particular temperature and pressure so will continue to drop due to being too dense. When the temperature increases as the crystals drop through the atmosphere down towards the ground the crystals will start to melt and might turn into rain according to the temperature profile.

Question 33

what is interception

Answer 33

Water which is stopped by vegetation

Question 34

3 types of rainfall

Answer 34

Relief: prevailing winds encounter a barrier so the air is forced up, cools, condenses and forms rain.

Convectional: a parcel of air is heated which then rises. As it rises it is then cooled adiabatically. It then goes beyond its dew point so condenses.

Frontal: dense cold air remains close to the ground acting as a barrier to the light warm air which means that the warmer air is forced up above the cold air.

Question 35

What is infiltration?

Answer 35

the process by which water on the ground surface enters the soil

Question 36

What is porosity?

Answer 36

Volume of pore space in a material

Question 37

What is permeability?

Answer 37

ability to transmit water

Question 38

What is percolation?

Answer 38

the downward movement of water through pores and other spaces in soil due to gravity

Question 39

Oceans contain how much of the Earth’s water?

Answer 39

97%

Question 40

How much freshwater is stored in ice caps?

Answer 40

3/4