4.11 – Understand the biological consequences of pollution of air by sulphur dioxide and
by carbon monoxide.
– Sulphur dioxide reacts with rainwater to form sulphurous acid, which falls as acid rain.
– Carbon monoxide is created as a result of incomplete combustion.
• Carbon monoxide binds to haemoglobin in the bloodstream which reduces the
capacity to carry oxygen.
4.12 – Understand that water vapour, carbon dioxide, nitrous oxide, methane and CFCs
are greenhouse gases.
– Greenhouse gas: Gas that contributes to global warming by absorbing long-wave
infrared radiation and trapping heat.
– Water vapour, carbon dioxide, nitrous oxide, methane and CFC (chlorofluorocarbons)
are greenhouse gases.
4.13 – Understand how human activities contribute to greenhouse gases.
– Many human activities contribute to the release of greenhouse gases.
• Combustion releases carbon dioxide.
• Keeping large numbers of livestock releases methane.
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.
– An increase in greenhouse gases results in an enhanced greenhouse effect.
– This may lead to global warming and its consequences.
• Melting ice caps.
• Extremes of climate.
• Enhanced natural disasters.
• Extinction of species.
4.15 – Understand the biological consequences of pollution of water by sewage,
including increases in the number of micro-organisms causing depletion of oxygen.
– An increase in the number of microorganisms is caused by pollution of water by
sewage.
– Microorganisms respire and use up oxygen, causing the water environment to become
anoxic.
4.16 – Understand that eutrophication can result from leached minerals from fertiliser.
– Eutrophication can result from leached minerals from fertiliser.
• Algae forms as minerals are leached into waterways.
• Algae blooms form and block the sunlight.
• Without sunlight, plants die as there is a lack photosynthesis.
• Bacteria respires by decomposing on dead matter.
• Anoxic conditions causes animals to die.
4.17 – Understand the effects of deforestation, including leaching, soil erosion,
disturbance of the water cycle and of the balance in atmospheric oxygen and carbon
dioxide.
– Leaching: Loss of nutrients from the soil.
– Soil erosion: Weakened soil.
– Water cycle is disturbed.
– Imbalance in atmospheric oxygen and carbon dioxide.