THE CARBON CYCLE

PHOTOSYNTHESIS

combines carbon dioxide with water using chlorophyll to trap sunlight to create organic molecules such as glucose. In the process of photosynthesis carbon dioxide is taken in therefore photosynthesis is responsible for reducing the atmospheric CO2 level.

FEEDING

when the primary consumer consumes the producer it takes in the producers carbons and uses it to grow. the primary consumer is then eaten by the secondary consumer, carbon is being passed along the food chain.

RESPIRATION

respiration combines glucose and oxygen to produce energy, its waste product is carbon dioxide, respiration is responsible for increasing the car dioxide levels in the atmosphere.

DECOMPOSITION

in the death of an organism the organic molecule that remain are broken down resulting in the release in carbon dioxide into the atmosphere.

COMBUSTION

1. combustion from the burning of fossil fuels produces carbon dioxide.

2. forest fires and grassland fires also contribute to the carbon dioxide levels in the atmosphere.

4.14 increase in greenhouse gases results in an enhanced greenhouse effect and that this may lead to global warming and its consequences

- The enhanced green house effect is brought about by pollution molecules such as carbon dioxide, methane and water vapour, these are green house gases.
- These gases will increase in concentration in the upper atmosphere, the consequences of this are that the infrared light from the earths surface will be increasingly re-immited back on to the earths surface rather than escaping into deep space, this raises the average global temperature or 'global warming'
PREDICTIONS IN THE CONSEQUENCES ARE:
- melting of ice caps
- raised sea levels
- changing ocean currents
- change the way in which the winds are generated
and these factors will contribute to a larger picture called 'climate change'
- changing the distrubution of biomass and ecosystems

4.13 how human activities contribute to greenhouse gases

1. FOSSIL FUELS
the combustion of fossil fuels from industries, cars and domestically
2. FARMING
cows produce methane which is a green house gas
3.  CLOUDS
evaporation of water forming water vapours
4. REFRIGERATION/SOLVENTS (CFCs)
substances containing chlorine, fluorine and carbon

4.12 recall that water vapour, carbon dioxide, nitrous oxide, methane and CFCs are greenhouse gases

a) UV light from the sun, short wave length with high energy

b) 50% of this light is reflected back out into deep space main cause of this reflection is clouds

c) Absoption of the light into the earths surface where UV light is converted into Infrared

d) Infrared light with longer waves being immited back outwards

e) some of Infrared is lost in space as heat

f) green house gases such as water vapour, carbon dioxide and methane 

g) when the infrared hits these molecules it takes in the energy and re-immites the infrared in all directions including downwards to the earths surface warming the surface of the earth. this is called the green house effect.

ENHANCED GREENHOUSE EFFECT 

is when more of the greenhouse gases are produced absorbing more of the infrared reflecting out of earth and immiting it back onto the earths surface increasing the temperature further leading to climate change

CFC - Cluorofluorocarbon

effects the ozone layer which absorbs UV light making it less efficient in absorbing UV light.

4.11 understand the biological consequences of pollution of the air by sulphur dioxide and carbon monoxide

SULPHUR DIOXIDE ( SO2 gas )
- is produced in the combustion of fossil fuels and also by vehicles in the combustion of petrol
- when SO2 gas is produced it reacts with water vapour in the air and forms sulphuric acid which is found     in the water that condenses as clouds, this is known as acid rain.
EFFECTS OF ACID RAIN
acid rain effects plants and animals in a variety of ways
PLANTS
- the trees are 'burned' from the direct effect of the sulphuric acid, in areas where there is acid rain the tops of the trees are often found dead.
- when there is acid rain calcium ions and magnesium ions -which are used by the plant in the process of making chlorophyll- are 'leached' from the soil meaning that the plant can no longer obtain those substances  making the plant suffer from chlorosis ( the yellowing of the leaves )
ANIMALS
- the acid rain precipitation will form streams leading into the rivers and lakes, reducing the PH in the water; which releases aluminium ions effecting the fish in the lakes and rivers, aluminum ions thickens the mucus which lines the fishes gills reducing the efficiency in which the fish can take in oxygen, killing the fish.

CARBON MONOXIDE    CO
is produced when fossil fuels are burnt with insufficient amounts of oxygen.
- carbon monoxide combines with haemoglobin in red blood cells, forming carbamino haemoglobin which blocks the haemoglobin from carrying oxygen, reducing oxygen circulation, this is toxic and can be fatal