Ecosystems and sustainability — AQA A-Level Geography
Test yourself on Ecosystems and sustainability with AQA A-Level practice questions.
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Ecosystems and sustainability explained
Biodiversity encompasses the variety of life at genetic, species, and ecosystem levels.
Read the full explanation
You must understand both global trends, such as the rapid decline of tropical biomes, and local trends, like the loss of specific native flora in a UK woodland. The causes of this decline are multifaceted, including habitat destruction, climate change, pollution, and invasive species. You need to quantify the rates of decline, recognising that current extinction rates are estimated to be hundreds of times higher than the natural background rate, indicating a potential sixth mass extinction. Finally, evaluate the impacts of this loss, ranging from the collapse of local food webs and reduced ecosystem resilience to global consequences like compromised food security and the loss of potential medicinal resources.
Ecosystems and their importance for human populations in the light of continuing population growth and economic development. Human populations in ecosystem development and sustainability.
Ecosystems provide vital provisioning, regulating, cultural, and supporting services essential for human survival and wellbeing. As the global population continues to grow and economic development expands, the demand for resources like timber, food, and fresh water intensifies, placing unprecedented pressure on these natural systems. For example, rapid industrialisation often leads to deforestation and habitat degradation. However, human populations also play a crucial role in ecosystem development and sustainability through active management, conservation strategies, and restoration ecology. Sustainable practices, such as agroforestry or the establishment of protected marine reserves, demonstrate how human intervention can balance economic needs with the long-term viability and resilience of ecosystems.
Your focus
- Define biodiversity across genetic, species, and ecosystem levels.
- Compare and contrast current trends in biodiversity at both local and global scales.
- Evaluate the causes, accelerated rates, and multifaceted impacts of contemporary biodiversity decline.
Show all 6 objectives
- Categorise the services provided by ecosystems to human populations.
- Analyse the dual pressures of population growth and economic development on ecosystem integrity.
- Evaluate the effectiveness of human interventions in achieving ecosystem sustainability.
Ecosystems and sustainability exam tips
Marking Points
- Define biodiversity comprehensively, including genetic, species, and ecosystem diversity.
- Contrast global biodiversity trends, such as widespread tropical deforestation, with local trends, such as changes in a specific nature reserve.
- Identify and explain the primary anthropogenic causes of biodiversity loss, such as land-use change, overexploitation, and climate change.
- Provide evidence for the rates of declining biodiversity, comparing current extinction rates to historical background rates.
- Assess the ecological and human impacts of declining biodiversity, including loss of ecosystem services and reduced ecological resilience.
- Identify specific ecosystem services (provisioning, regulating, cultural, supporting) and link them directly to human wellbeing and survival.
- Explain how exponential population growth increases absolute resource consumption, leading to habitat destruction or overexploitation.
- Evaluate the impact of economic development, such as industrialisation or commercial agriculture, on ecosystem degradation and biodiversity loss.
- Assess the role of human management in promoting ecosystem sustainability through conservation, legislation, or sustainable yield practices.
Examiner Tips
- 💡Use specific indices, such as the Living Planet Index, to provide concrete evidence when discussing global rates and trends of biodiversity decline.
- 💡Link the causes of biodiversity loss directly to their impacts; for example, explain how agricultural runoff causes eutrophication, leading to local fish mortality.
- 💡When discussing impacts, categorise them into ecological impacts, like food web collapse, and anthropogenic impacts, like loss of economic resources, to demonstrate breadth of knowledge.
- 💡Use the Millennium Ecosystem Assessment framework (provisioning, regulating, cultural, supporting) to structure answers on the importance of ecosystems.
- 💡Provide specific, named examples of sustainable management strategies, such as debt-for-nature swaps or ecotourism in Costa Rica.
- 💡When evaluating sustainability, explicitly weigh short-term economic gains against long-term ecological degradation.
Common Mistakes
- Error: Defining biodiversity solely as the number of different species. Correction: Broaden the definition to include genetic diversity within species and the variety of ecosystems.
- Error: Confusing local and global trends or providing only global examples. Correction: Ensure you have distinct examples for both scales, such as global coral reef bleaching versus local hedgerow removal.
- Error: Discussing causes of decline without referencing the rate of change. Correction: Explicitly mention the accelerated speed of current biodiversity loss compared to natural evolutionary timescales.
- Viewing human impacts solely as negative; correction: acknowledge that human populations can also actively restore and sustainably manage ecosystems.
- Confusing economic development with population growth; correction: treat them as distinct drivers, where development relates to rising affluence and per capita consumption, while population growth relates to absolute demographic numbers.
- Using vague terms like 'pollution' without context; correction: specify the type of pollution (e.g., agricultural runoff causing eutrophication) and its exact impact on ecosystem services.