Summary of ideas

Based on the syllabus-specifications for students taking the AQA, Edexcel and OCR GCSE level biology examinations (~US grades 9-10).

Biodiversity is the variety of life forms in a given area, ensuring ecological stability. It is threatened by deforestation, habitat destruction, pollution, and climate change.

Conservation efforts focus on sustainability and protection of species.

Biodiversity

Biodiversity refers to the variety of life on Earth, encompassing diversity within species, between species, and of ecosystems.

It plays a crucial role in maintaining ecological balance and resilience.

Definition of Biodiversity

Biodiversity can be defined as the variety of different species of organisms living in a habitat.  It includes:

• Species diversity – the number of different species in an ecosystem.
• Genetic diversity – the variation of genes within a species.
• Ecosystem diversity – the range of different habitats within a given area.

Biodiversity is essential for ecosystem stability and ensures sustainability of life on Earth.

Why is Biodiversity Important?

• Maintains ecosystem stability – diverse ecosystems can better withstand environmental changes.
• Provides resources for humans – food, medicine, materials, and ecosystem services (e.g., pollination).
• Enhances genetic variability – ensures populations adapt to changing environments.
• Supports food webs – interdependent relationships between organisms help maintain balance.

Threats to Biodiversity

Human activities have led to a decline in biodiversity. Key threats include:

1. Deforestation – destruction of forests for agriculture, logging, and urban development.
2. Habitat destruction – conversion of land for farming or building, reducing available natural environments.
3. Climate change – shifts in temperature and weather patterns affecting species' survival.
4. Pollution – chemicals, plastics, and waste negatively impact ecosystems.
5. Overexploitation – excessive hunting, fishing, and harvesting leading to species decline.
6. Invasive species – non-native species introduced to ecosystems outcompete native species.

Conservation of Biodiversity

Efforts to protect biodiversity focus on sustainable management and conservation strategies, including:

• Protected areas (e.g., national parks, nature reserves).
• Legislation (e.g., international agreements such as CITES).
• Breeding programmes (e.g., zoos and seed banks for endangered species).
• Sustainable practices (e.g., afforestation, reducing waste and pollution).

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See also

Ecosystems - biotic & abiotic factors - interactions between organisms - interdependency

and

Food chains, food webs, trophic levels, pyramids of biomass, transfer efficiency, pyramids of numbers