How this is tested: This sub-topic is examined as a short Explain or Discuss question.
How to score
- A common task is to explain how ex situ conservation helps preserve an endangered species.
- So you need to give clear reasons (breed safely, raise numbers, save genes, reintroduce, act as a back-up), not just a list of places.
- Mark schemes credit one mark per distinct reason.
- Aim for as many separate points as the marks allow.
IB-style question — explain ex situ conservation
A species of forest parrot has fewer than 60 birds left in the wild, and its forest is still being cleared. Conservationists set up a captive-breeding centre for the parrot. Explain how this ex situ programme helps preserve the species. [4]
How to build a 4-mark answer
- Make a point about safety. In the centre the parrots breed away from predators, poachers and habitat clearance, so more chicks survive.
- Make a point about numbers. Under expert care the population can be raised quickly, building a larger, safer back-up population.
- Make a point about genes. A studbook / gene bank keeps track of breeding so genetic variety is preserved and inbreeding is reduced.
- Answer the command term — say HOW it preserves the species. Once numbers and habitat allow, captive-bred parrots can be reintroduced to the wild, so the species is preserved even though its wild habitat is still threatened.
Final answer
Ex situ breeding lets the parrots breed safely away from predators/poachers/clearance, raises their numbers under expert care, preserves genetic variety through managed breeding, and provides birds to reintroduce — so the species survives even while its wild habitat is at risk.
What scored the marks: Four separate reasons, each a different idea: safe breeding, raised numbers, genetic variety preserved, and a back-up for reintroduction.
Listing places ("zoo, seed bank, botanic garden") with no reasons would not score on an Explain question.
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