Biodiversity & Human Interaction (AQA GCSE Biology): Revision Notes
Maintaining biodiversity
Human activities have caused biodiversity to decrease around the world. However, scientists and concerned people have started programmes to stop this decline and protect our natural environment.
Why we need to take positive action
There are four main reasons why people work to maintain biodiversity:
Moral and ethical reasons
Humans have a responsibility to look after other species and protect them from harm. We should respect all living things and their right to exist.
Aesthetic reasons
People enjoy seeing the variety of different species in natural habitats. Biodiversity makes our world more beautiful and interesting to explore.
Ecosystem structure
All organisms in an ecosystem depend on each other. For example, decomposer microorganisms are essential for the carbon cycle to work properly. If we lose species, entire ecosystems can collapse.
Critical Ecosystem Interdependence
When species are lost, the delicate balance of ecosystems can be disrupted, potentially leading to complete ecosystem collapse. This demonstrates why every species, no matter how small, plays a vital role in maintaining ecological stability.
Value to humans
Many species are useful to humans in practical ways. Plants might provide new medicines, and wildlife can attract tourists, creating jobs and income for local communities.
Conservation programmes
Scientists have created several programmes to reduce or reverse the loss of biodiversity:
Protecting and regenerating habitats
Special areas like wetlands are protected to keep rare species safe. These habitats are restored when they become damaged.
Replanting hedgerows
Farmers plant new hedgerows to provide homes and food for wildlife. This creates corridors that connect different habitats.
Wildlife Corridors
These connecting pathways are essential for allowing animals to move between habitats safely, enabling them to find food, mates, and suitable breeding sites. Without these corridors, animal populations can become isolated and vulnerable.
Recycling resources
Instead of dumping waste in landfill sites, materials are recycled. This reduces harmful activities like quarrying for new materials.
Reducing deforestation
Cutting down fewer trees helps protect forest habitats and the species that live there.
Benefits of replanting forests
Key Benefits of Reforestation Programmes:
- Habitat restoration - Trees provide homes for endangered species
- Preventing soil erosion - Tree roots hold soil together and stop it washing away
- Reducing carbon dioxide - Trees absorb carbon dioxide during photosynthesis, helping to tackle climate change
Protecting endangered species
Understanding Species at Risk
Extinction happens when no living individuals of a species remain anywhere in the world.
Endangered species face a high risk of extinction in the near future. Their populations have become dangerously small.
Breeding programmes help endangered species by:
- Carefully planning reproduction to increase population numbers
- Preventing inbreeding (breeding between closely related individuals)
- Breeding animals or plants over several generations in safe conditions
Monitoring Ecosystem Health
Scientists monitor large carnivores like tigers because they are at the top of food chains. If there are many large carnivores in an area, it suggests the ecosystem is healthy with plenty of other species to support them.
Key Points to Remember:
- Human activities reduce biodiversity, but conservation programmes can help reverse this trend
- We protect biodiversity for moral, aesthetic, ecosystem and practical reasons
- Key conservation methods include habitat protection, reforestation, recycling and reducing deforestation
- Breeding programmes help endangered species avoid extinction by carefully managing reproduction
- Monitoring large carnivores helps scientists assess the health of entire ecosystems