Biodiversity
Build confidence in Biodiversity for GCSE Biology with this free worksheet and full mark scheme — Foundation and Higher exam-style questions with worked answers for AQA, Edexcel and OCR. High biodiversity makes an ecosystem more stable, yet human activity often reduces it.
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These worksheets and mark schemes are original, written for Virtus Academy and checked against the current AQA, Edexcel and OCR specifications. Every worksheet comes with a full mark scheme.
Topic overview
Biodiversity is the variety of all the different species of organisms on Earth, or within an ecosystem.
A great biodiversity ensures the stability of ecosystems, by reducing the dependence of one species on another for food, shelter and the maintenance of the physical environment. The future of the human species relies on maintaining a good level of biodiversity.
Many human activities are reducing biodiversity, and only recently have measures been taken to try to stop this reduction. The main pressures come from a rapidly rising human population and an increasing standard of living, which together produce more waste and greater demand for land and resources.
Revision notes
What biodiversity means
Biodiversity is the variety of all the different species of organisms on Earth, or within an ecosystem.
High biodiversity means many different species are present, each occupying its own role in the community.
Why it matters
Great biodiversity ensures the stability of ecosystems.
It reduces the dependence of one species on another for food, shelter and the maintenance of the physical environment. If one species declines, others can fill its role, so the ecosystem does not collapse.
Pressures on biodiversity
The human population is rising rapidly and the standard of living is increasing.
More resources are used and more waste is produced. Unless waste is properly handled, more pollution is caused. Human activity is reducing biodiversity, and only recently have measures been taken to address it.
Key points
- Biodiversity is the variety of species present.
- High biodiversity ensures ecosystem stability.
- It reduces species' dependence on one another.
- Human population growth reduces biodiversity.
- Rising living standards increase resource use and waste.
- The future of humans relies on maintaining biodiversity.
Worked examples
Example 1
Define biodiversity. [1 mark]
Model answer
Biodiversity is the variety of all the different species of organisms on Earth, or within an ecosystem (1 mark).
Example 2
Explain why a high level of biodiversity makes an ecosystem more stable. [3 marks]
Model answer
High biodiversity means many different species are present (1 mark). This reduces the dependence of any one species on another for food, shelter or maintaining the physical environment (1 mark). If one species declines, others can fill its role, so the ecosystem does not collapse (1 mark).
Example 3
Explain how a rising human population reduces biodiversity. [2 marks]
Model answer
A larger population uses more resources and produces more waste (1 mark), causing pollution and destroying habitats, which reduces the number of species that can survive (1 mark).
Common mistakes
Defining biodiversity as the number of organisms.
It is the variety of different species, not the number of individuals.
Saying high biodiversity is only good for wildlife.
The specification states the future of the human species relies on it.
Not explaining the stability link.
Say that reduced dependence between species is what provides stability.
Giving only pollution as a cause of reduced biodiversity.
Habitat destruction and resource use are also major factors.
Exam tips
- Define biodiversity as variety of species.
- Explain stability through reduced interdependence.
- Link population growth to resource use and waste.
- Mention that humans depend on biodiversity too.
Key terms
- Biodiversity
- The variety of different species in an ecosystem or on Earth.
- Ecosystem stability
- The ability of an ecosystem to resist change.
- Species
- A group able to interbreed to produce fertile offspring.
- Standard of living
- The level of resources and comfort available to a population.
Related topics
Written and reviewed against the current AQA, Edexcel and OCR specifications. Spotted an error? Let us know.