GCSE Biology · Edexcel 1BI0 · Topic 9B
Biodiversity and human impacts
Key points
- Biodiversity is the variety of living organisms in an area. High biodiversity makes ecosystems more stable.
- Human threats: eutrophication (fertilisers run into water, algae grow, plants die, bacteria use up oxygen and fish die), fish farming (disease and waste in the wild), non-native species that out-compete local ones.
- Conservation: protected areas, breeding programmes and seed banks.
- Reforestation restores habitats and helps take up carbon dioxide.
- Separate science: food security depends on population growth, changing diets, pests, climate change and the cost of farming. Indicator species such as lichens and mayfly larvae show pollution levels.
- Weigh the benefits of human activities against their costs to ecosystems.
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Biodiversity is the variety of living organisms in an area. A diverse ecosystem is more stable, because many species depend on one another and the loss of one is less likely to collapse the whole web. This sub-topic covers how human…
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