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CAIE A-Level Biology A2 18.3.5 Invasive Alien Species Questions

Practise explaining why invasive alien species need control, from competition and predation to disease, trophic cascades, habitat damage and wider economic impacts.

Syllabus
2028–2030
Course
Biology 9700
Level
A2

Exam points

  • Explain why rapid spread and competition for food, space, light, pollinators or other resources can displace native species.
  • Trace how predation, toxicity and altered trophic relationships can disrupt food webs and reduce native populations.
  • Assess disease transmission and direct risks to human or animal health as reasons for controlling an invasive species.
  • Justify control by linking invasive species to biodiversity loss, habitat damage and impacts on agriculture, tourism or other ecosystem services.

CAIE A-Level Biology A2 18.3.5 Invasive Alien Species Questions question 1

[Maximum number: 4]

The Asian common toad, Duttaphrynus melanostictus, arrived accidentally in eastern Madagascar in 2010 on a ship.

Fig. 9.1 shows an Asian common toad.

Fig. 9.1

Fig. 9.1

The Asian common toad is now regarded as an invasive alien species because:
- it breeds fast in the warm, wet conditions of eastern Madagascar
- it can travel up to 2.5 km per year
- its skin contains poison, which is highly toxic to humans and predators.

Suggest ways in which the Asian common toad may affect the ecosystem of eastern Madagascar.

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