What Is Biodiversity, and Why Does It Matter?
Learn what biodiversity means, why it keeps ecosystems stable, how humans reduce it, and how biodiversity can be maintained for AQA GCSE Biology.
Biodiversity is the variety of all the different species of organisms on Earth or within a particular ecosystem. It matters because greater biodiversity usually makes ecosystems more stable and helps protect resources on which humans depend.
Why does biodiversity matter?
An ecosystem is the interaction between a community of living organisms and the non-living parts of their environment.
Species within an ecosystem are interdependent. This means they depend on one another for things such as:
- food
- shelter
- pollination
- seed dispersal
- maintaining the physical environment
High biodiversity reduces an ecosystem’s dependence on any one species. If one species declines, others may still perform a similar role or provide an alternative food source. This makes the ecosystem less likely to be seriously disrupted.
Biodiversity also matters to humans. We rely on living organisms for food, medicines and useful materials. The future of the human species therefore depends on maintaining a good level of biodiversity.
A simple example
Imagine an ecosystem in which one insect species pollinates nearly every plant. If disease kills that insect, many plants may fail to reproduce. This then reduces food for other organisms.
If several different insects pollinate the plants, the loss of one species is less likely to cause such a large effect. The greater biodiversity makes the ecosystem more stable.
How can humans affect biodiversity?
Human activities can reduce biodiversity through pollution, deforestation, destruction of habitats and climate change. Biodiversity can be maintained using measures such as:
- breeding programmes for endangered species
- protecting and restoring rare habitats
- reducing deforestation and carbon dioxide emissions
- reintroducing hedgerows and field margins
- recycling instead of sending waste to landfill
Common exam mistake: Do not define biodiversity as simply “the number of organisms”. It means the variety of different species, not the total population size.
This answer assumes AQA GCSE Biology 8461 separate science. The biodiversity content covered here applies to both Foundation and Higher tiers and is also shared with Combined Science.
