The reasons for conserving biodiversity, the methods of in-situ and ex-situ conservation, the use of seed banks and zoos, and the balance between conservation and human needs.

What this dot point is asking

Edexcel wants you to give reasons for conserving biodiversity, describe in-situ and ex-situ conservation methods including seed banks and zoos, and discuss how conservation is balanced against human needs. Compare and evaluate questions are common, so always weigh advantages against disadvantages and reach a judgement.

Why conserve biodiversity

A loss of genetic diversity can also reduce a species' ability to adapt to change.

Methods of conservation

• In-situ keeps species in their environment so they continue their natural behaviour, breed naturally and the whole habitat (and the other species in it) is preserved, but it is hard to protect against threats such as poaching, disease and habitat loss.
• Ex-situ (zoos, captive breeding, botanic gardens, seed banks) protects species when the habitat is too damaged, allows controlled breeding to maintain genetic diversity, and seed banks store seeds cheaply for long periods in a small space. The drawbacks are that it removes organisms from their natural environment, populations are small with limited gene pools, captive animals may not breed or may struggle to survive when reintroduced, and it can be expensive.

Seed banks such as the Millennium Seed Bank store dried, frozen seeds that can be germinated decades later, providing a cheap insurance policy for plant species and crop wild relatives.

Balancing conservation and human needs

Conservation often conflicts with human needs such as farming, building, fishing and resource use. Sustainable approaches try to balance protecting biodiversity with allowing people to use land and resources, for example through managed reserves, sustainable harvesting quotas, ecotourism that gives local people an income from protecting wildlife, and education. International agreements such as CITES (which restricts trade in endangered species) and the Convention on Biological Diversity coordinate efforts between countries.

Examples in context

Example 1. The Arabian oryx. The Arabian oryx was hunted to extinction in the wild by 1972. A captive breeding programme in zoos (ex-situ) bred the survivors, carefully managing matings to maintain genetic diversity, and reintroduced them to protected reserves (in-situ). The species now numbers over a thousand in the wild. This shows ex-situ and in-situ methods working together, the key exam point.

Example 2. Marine protected areas and fishing. No-take zones around coral reefs protect breeding fish populations (in-situ), but they conflict with local fishing communities who lose access. Managed solutions allow limited sustainable fishing in buffer zones and use the protected core to restock surrounding waters, illustrating the balance between conservation and human needs.

Try this

Q1. Give one advantage of in-situ conservation over ex-situ conservation. [1 mark]

• Cue. Species remain in their natural habitat and continue natural behaviour, and the habitat is also preserved.

Q2. Explain one economic reason for conserving biodiversity. [2 marks]

• Cue. Wild species are sources of food crops and medicines, and ecosystems provide services such as pollination, which have economic value.