AQA GCSE Biology 4.7.3 Biodiversity and the Effect of Human Interaction on Ecosystems Exam Questions

About AQA GCSE Biology 4.7.3 Biodiversity and the Effect of Human Interaction on Ecosystems

This section of AQA Ecology, examined on Paper 2, looks at why biodiversity matters and how human activity threatens it. It covers pollution of water, air and land as the human population grows, land use, the destruction of peat bogs, deforestation, global warming, and the programmes used to protect biodiversity. It links to the carbon cycle in 4.7.2 and to food security in 4.7.5. Examiners regularly give data on emissions, land use or species numbers and ask you to interpret trends, explain biological consequences, and evaluate conservation measures, including conflicting pressures between people and the environment.

What you need to know

• 4.7.3.1 Biodiversity Biodiversity is the variety of all the different species of organisms on Earth, or within an ecosystem. High biodiversity ensures the stability of ecosystems by reducing the dependence of one species on another for food, shelter and maintenance of the physical environment.
• 4.7.3.2 Waste management Rapid human population growth and rising living standards use more resources and produce more waste. Pollution can occur in water from sewage, fertiliser or toxic chemicals; in air from smoke and acidic gases; and on land from landfill and toxic chemicals. Pollution kills plants and animals, reducing biodiversity.
• 4.7.3.3 Land use Humans reduce the land available for other organisms by building, quarrying, farming and dumping waste. Destroying peat bogs to produce garden compost reduces habitats and releases carbon dioxide when the peat is burned or decays.
• 4.7.3.4 Deforestation Large-scale deforestation in tropical areas provides land for cattle and rice fields and for crops grown for biofuels. It reduces biodiversity and increases atmospheric carbon dioxide because fewer trees photosynthesise and wood is burned or decays.
• 4.7.3.5 Global warming Rising levels of carbon dioxide and methane contribute to global warming. Consequences include loss of habitat, changes in species distribution, changes in migration patterns and reduced biodiversity.
• 4.7.3.6 Maintaining biodiversity Measures include breeding programmes for endangered species, protecting and regenerating rare habitats, reintroducing field margins and hedgerows where farmers grow only one crop, reducing deforestation and carbon dioxide emissions, and recycling resources rather than dumping waste in landfill.

Common mistakes in 4.7.3 Biodiversity and the Effect of Human Interaction on Ecosystems

• Saying global warming is caused by the hole in the ozone layer. It is caused by increased greenhouse gases such as carbon dioxide and methane.
• Saying deforestation increases carbon dioxide only because of burning. Fewer trees also means less carbon dioxide is removed by photosynthesis, and decay by microorganisms releases carbon dioxide.
• Giving vague answers such as 'it harms animals'. Explain the specific biological effect, for example loss of habitat or food sources reducing biodiversity.
• Treating biodiversity as the number of individuals. It is the variety of different species.

Try three 4.7.3 Biodiversity and the Effect of Human Interaction on Ecosystems exam-style questions