4.14 Enhanced Greenhouse Effect

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

• As the green house gases increases it means that more infra-red light will be trapped therefore more global heating 
• Consequences: 
• Polar ice caps melt causing increase in sea level and change in global water currents 
• Average global temperature effects the habitat of animals, biomes will change and move 
• Ice caps will disappear, deserts will grow. forest will dry up 

4.13 Greenhouse gases

4.13 Understand how human activities contribute to greenhouse gases.

• Human activities cause an increase in green house gases 
• This is because we burn fossil fuels and this causes more green house gases to be released 
• Things such as: Cars, Factories, Homes, Farming (paddy fields and cow farts produce Methane), refrigerating and aerosol cans (produce CFC's)

4.12 Greenhouse Effect

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

• Uv light is short wavelength with high energy
• When it comes into the atmosphere it gets reflected of the earth's surface back into space as infra-red light 
• Green house gases such as water vapour, methane, carbon dioxide etc trap the infra-red rays 
• Once the heat is trapped the overall global temperature increases 

4.11 Gas pollution

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






Carbon Monoxide:

• Caused by burning of fossil fuels and coal with insufficient oxygen 
• Is very to toxic to living things especially humans 
• Bonds with the Hemoglobin in the red blood stream and causes oxygen depletion in the blood stream

When fuels are burnt toxic gases are produced
Sulphur dioxide:

• Is caused by the burning of coal and oil from factories 
• Sulphuric acid forms acid rain (changes the ph of the water)
• Causes plants leaves to burn and roots to be leached of minerals resulting in no growth 
• Causes lakes to become acidic and reduces oxygen levels suffocating fish

4.7 Energy Efficieny

4.7 Explain why only about 10% of energy is transferred from one trophic level to the next.

• Only 10% of Energy moves on from one animal to the next 
• The secondary consumer only gets 1% of the original energy 
• Consumers do not get 100% of the energy because energy is used up in respiration and excretion

4.6 Energy and Substances in Food chains

4.6 Understand the transfer of substances and of energy along a food chain.

• Producers change the energy from the sun into chemical stored energy that they can use for respiration 
• Chemical energy are lipids, carbohydrates and proteins 
• The producer breaks the bonds in the molecules which contain energy 
• When something eats the producer the enrgy is passed on 

4.5b Food webs

4.5b Understand the concepts of food chains, food webs, pyramids of number, pyramids of biomass and pyramids of energy transfer.



• Shows ecosystem
• Shows interaction (feeding) of a community of organism
• Organisms have multiple predators/multiple prey• Feeding at different tropic levels 
• It is a link of many different food chains