Non-biodegradable plastic is a major source of pollution in both land and water habitats. Explain why non-biodegradable plastic causes harm to organisms living in these habitats.

Cambridge International IGCSE Biology (0610) — 20.3 Pollution · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

Non‑biodegradable plastic cannot be broken down by decomposers, so it persists and accumulates in the habitat.
Animals may mistake plastic for food and ingest it, causing internal injury, blockages or death.
Animals can become entangled in plastic debris, which can restrict movement, cause injury or kill them.
The loss of individuals reduces biodiversity and can disrupt the food chain, affecting other species in the ecosystem.

Examiner tips

  • Use the exact phrase ‘cannot be broken down by decomposers’ to gain the first point. Show the chain of harm: persistence → ingestion/entanglement → injury/death → ecosystem impact. Keep each point short and separate with a line break or bullet for clarity.

Common mistakes

  • Confusing biodegradable with non‑biodegradable; forgetting that plastic does not decompose. Failing to mention both ingestion and entanglement. Using vague terms like ‘pollution’ instead of specific effects on organisms.

Mark scheme (4 marks)

  1. Non-biodegradable plastic cannot be broken down by decomposers, so it persists / accumulates in the habitat
  2. Animals may attempt to eat plastic, leading to injury or death
  3. Animals can become entangled in plastic, causing injury or death
  4. The death of organisms affects the whole food chain / reduces biodiversity

Key terms in this question

non-biodegradable plastic · pollution

Related

More Pollution questions

▶ Try answering this question with AI marking (free) →