Extinction & Conservation IGCSE Biology 0610

Extinction and Conservation Genetics: Preserving Biodiversity

Biology editorial review is supported by the named review panel. Reviewer participation may vary by guide. Checked against Cambridge IGCSE Biology 0610 (2026–2028); last reviewed August 2026.

Key concept

Extinction occurs when a species can no longer survive and reproduce. Causes include habitat destruction, climate change, new predators or diseases, and pollution. Conservation genetics involves maintaining genetic diversity through breeding programmes, gene banks and habitat protection.

Extinction and conservation questions often overlap with ecology and human influences. Students must explain why genetic diversity matters for species survival and describe specific conservation strategies, linking each to the preservation of alleles in the population.

Causes of extinction

A species becomes extinct when all individuals of that species die without reproducing. Causes include:

Habitat destruction: Deforestation, urbanisation and agriculture remove the environments species depend on. Climate change: Rapid changes in temperature and rainfall alter habitats faster than species can adapt. New predators, competitors or diseases: Introduced species can outcompete native species or prey upon them. Pollution: Toxic substances can reduce reproductive success. Overexploitation: Overhunting, overfishing or overcollection can reduce populations below sustainable levels.

Why genetic diversity matters

Genetic diversity is the range of different alleles within a population. A population with high genetic diversity is more likely to contain individuals with alleles that allow survival when conditions change, such as resistance to a new disease or tolerance to higher temperatures.

A population with low genetic diversity is vulnerable because if conditions change, few or no individuals may have the alleles needed to survive. This is why small, isolated populations and selectively bred populations are particularly at risk of extinction.

Conservation strategies

Captive breeding programmes: Endangered species are bred in zoos or wildlife centres, with careful management of genetic records to maintain genetic diversity and avoid inbreeding. Offspring may be released into the wild when populations are stable.

Seed banks and gene banks: Seeds, sperm, eggs or DNA samples are stored under controlled conditions. These preserve genetic material from many varieties, including rare ones, for future use in breeding programmes or genetic research.

Habitat protection: National parks, nature reserves and marine protected areas prevent habitat destruction and allow populations to recover. This is the most effective long-term strategy because it preserves the entire ecosystem.

The role of education and legislation

Conservation also depends on laws that protect endangered species from hunting and trade (such as CITES), regulations that limit pollution and habitat destruction, and public education that encourages sustainable behaviour.

Exam answers should present conservation as a combination of scientific strategies (breeding programmes, gene banks) and social strategies (laws, education, sustainable development). A balanced answer covering both aspects earns more marks.

Try a focused question (3 marks)

Explain why maintaining genetic diversity is important for the long-term survival of a species.

Show the answer and marking guidance

Genetic diversity means a population has a wide range of different alleles.
If the environment changes, some individuals may have alleles that give them a survival advantage.
These individuals survive and reproduce, allowing the population to adapt by natural selection. Without diversity, the population may not contain suitable alleles and could become extinct.

Original Cambridge-style practice written for this site. It is not an official Cambridge past-paper question.

Common mix-ups to avoid

Check these points against your own answer before moving on.

Confusing species diversity (number of different species) with genetic diversity (range of alleles within a species).
Listing conservation strategies without explaining how they maintain genetic diversity.
Saying extinct species can be brought back (once truly extinct, the species cannot be recovered).
Forgetting to mention that captive breeding must manage genetics to avoid inbreeding.