A-Level Biology October/November 2024 Q9(a): The International Union for Conservation of Nature (IUCN) Red List of Threatened Specie…

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  Three factors that have contributed to the red ruffed lemur becoming critically endangered are:

  1. Loss of habitat: The lemur's native forest habitat in Madagascar has been significantly reduced due to deforestation for logging, agriculture (such as slash-and-burn farming), and mining. This fragmentation of the forest isolates populations and reduces the availability of food and nesting sites.
  2. Hunting/Poaching: The species is illegally hunted for bushmeat. This direct pressure on the population removes individuals, reducing population size and disrupting social structures, which can lower reproductive success.
  3. Climate Change: Changes in climate patterns can lead to an increase in the frequency and intensity of cyclones in Madagascar. These extreme weather events can destroy large areas of the lemur's habitat and cause direct mortality, leading to sudden population crashes.

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  How the marks are awarded

  • B1 — The first mark is awarded for identifying 'loss of habitat', as stated in the model answer's first point regarding deforestation.
  • B1 — The second mark is awarded for stating that the lemurs are 'hunted' or 'poached', as correctly identified in the second point of the answer.
  • B1 — The third mark is awarded for suggesting 'climate change' as a factor, with the example of cyclones provided in the model answer's third point.

  Common mistakes

  • Providing answers that are too vague, such as 'human activity' or 'pollution', without specifying a direct cause like deforestation or hunting.
  • Repeating the same marking point using different words, for example, stating 'deforestation' and 'loss of trees', which would only be awarded one mark for habitat loss.
  • Confusing the causes of endangerment with the consequences. For example, stating 'a small gene pool' is a characteristic of an endangered population, not the initial cause of its decline.
  • Only providing one or two reasons, even if well-explained, when three distinct points are required for the full three marks.

  Examiner tip: For 'suggest' questions about conservation, always consider the main categories of threats: habitat loss, overexploitation (hunting), introduced species (disease/competition), and climate change.

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