Unit 9: Natural Ecosystems & Human Activities:

2-Mark Question

1. Define a natural ecosystem.

Model Answer:

A natural ecosystem is a community of organisms interacting with each other and with the non-living components of their environment.

Why this works:

• Identifies a community of organisms (1 mark)

• Includes interactions between organisms and their physical environment (2nd mark)

4-Mark Question

2. Explain two ways in which human activities can damage natural ecosystems.

Model Answer:

Deforestation: Cutting down forests destroys habitats, causing a loss of biodiversity as plants and animals lose places to live and feed.

Pollution: Waste and chemicals released by human activities can contaminate soil and water, harming organisms and disrupting ecosystem processes.

Why this works:

• Two distinct human activities/impacts → 2 marks

• Each is explained through a clear cause-and-effect relationship → 2 marks

6-Mark Question

3. Discuss the advantages and disadvantages of establishing protected areas to conserve natural ecosystems.

Model Answer:

Protected areas restrict activities such as deforestation, hunting and development, allowing habitats and wildlife populations to be protected. They can maintain biodiversity and provide safe areas where endangered species can reproduce. Protected areas can also support tourism, providing income and employment for local communities.

However, restricting activities can reduce the amount of land available for farming, mining or settlement. Local people may lose access to resources they previously depended on, which can create conflict. Protected areas can also be difficult and expensive to monitor, particularly when they cover large areas.

Overall, protected areas can be highly effective for conserving biodiversity, but they are most successful when local communities are involved and the restrictions are properly enforced.

Why This Works:

• Advantages + disadvantages are balanced

• Environmental, social and economic factors are included

• Each point is explained rather than simply listed

• The conclusion evaluates conditions for success

8-Mark Question

4. Describe methods of conserving biodiversity and evaluate their importance.

Model Answer:

Biodiversity can be conserved by establishing protected areas where activities such as deforestation, hunting and development are restricted. Endangered species can also be protected through breeding programes, where individuals are bred in captivity and may later be released into suitable habitats. Laws can control hunting and the international trade in endangered species.

Habitats can also be restored by replanting trees, controlling invasive species and restoring damaged ecosystems. Sustainable forestry and fishing can allow natural resources to be used while preventing populations from being depleted. Education can encourage local communities and tourists to protect ecosystems and reduce damaging activities.

Conservation is important because biodiversity provides ecosystem services such as pollination, soil formation, water purification and carbon storage. Ecosystems also provide resources such as food, medicines and timber. However, conservation programes can be expensive and may conflict with the economic needs of local communities if restrictions prevent people from earning a living.

Overall, biodiversity conservation is essential for maintaining healthy ecosystems, but the most successful approaches are likely to combine habitat protection with sustainable resource use and local community involvement.

Why This Works:

• Describes multiple conservation methods

• Explains how each protects biodiversity

• Gives reasons why biodiversity is important

• Includes economic/social limitations

• Finishes with an evaluation

10-Mark Question

5. Assess the effectiveness of different strategies for reducing the environmental impacts of human activities on natural ecosystems.

Model Answer:

Human activities such as agriculture, deforestation, mining, fishing, urbanization and pollution can damage natural ecosystems. These activities may destroy habitats, reduce biodiversity, pollute air and water, and use natural resources faster than they can be replaced.

Protected areas are one strategy for reducing these impacts. Restricting development, hunting and resource extraction allows habitats and species to survive. However, protected areas may be difficult to enforce and can restrict the activities of local communities.

Sustainable resource management can allow resources to be used without completely destroying ecosystems. For example, selective logging can reduce damage to forests, while fishing quotas and minimum mesh sizes can help maintain fish populations. However, sustainable management depends on effective monitoring and enforcement.

Environmental laws can control pollution, deforestation and hunting, while environmental impact assessments can identify potential environmental damage before major developments are approved. These approaches can be effective, but enforcement may be difficult where governments lack funding or resources.

Education and community involvement are also important because local people are more likely to protect ecosystems when they understand their importance and receive economic benefits from conservation, such as ecotourism.

Overall, no single strategy is sufficient. Protected areas are particularly effective for protecting important habitats, while sustainable resource management allows people to continue using natural resources. The most effective approach is therefore to combine legal protection, sustainable resource use, environmental education and local community involvement.

Why This Works:

• Covers several management strategies

• Explains both how they work and their limitations

• Includes environmental, economic and social considerations

• Evaluates effectiveness rather than simply listing methods

• Ends with a clear overall judgement

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