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IGCSE · Cambridge (CIE) · 0654

Manage forests and fish stocks sustainably

Education, protected areas, quotas and replanting can conserve forests; fish conservation can use closed seasons, gear controls, quotas and monitoring.

Conservation · Cambridge IGCSE 0654 · B19.2

Mapped to the named 0654 section using teaching from the corresponding single-science course. A 0654-specific review of every Core and Supplement objective is still in progress. Written practice is self-checked; it does not demonstrate supervised laboratory competence or award an official Cambridge grade.

Before you begin

  • Know that organisms interact with other organisms and their environment.

Work on paper. Try each question before revealing help, and explain why your method works.

Quick readiness check

Which method limits the amount of timber removed?

What you will learn

  • Explain four methods for conserving forests
  • Explain six methods for conserving fish stocks

Conserve forests using several controls

Education can explain why forest resources need sustainable management. Protected areas restrict damaging activities in selected places. Quotas limit how much may be removed, and replanting replaces harvested trees so a forest can regenerate.

These methods can complement one another: quotas control the amount cut, replanting supports renewal, protected areas conserve important habitat, and education can encourage compliance. Their success depends on suitable enforcement and ecological conditions.

Allow fish populations and young fish to recover

Closed seasons prevent or limit fishing during selected periods, such as breeding periods. Protected areas provide places where fish are less disturbed. Quotas limit catches; controlled net types and mesh sizes can reduce capture of certain fish, including smaller individuals; monitoring checks stock status and management outcomes.

Education can support compliance and awareness. Sustainable fish management uses several methods because a quota alone may not protect breeding habitat or prevent catching young fish. Explain the purpose of the named controls without claiming they guarantee recovery.

Sources for this lesson

Pause and explain

Why may a fishery control net mesh size?

Put the idea to work

Worked example

A fishery catches many immature fish before they reproduce. Which gear control could help, and why?

Show the worked solution
  1. Use net type and mesh size to affect which fish are caught.
  2. Larger mesh openings can allow smaller fish to escape.

Answer Using a controlled net type and a suitable mesh size can reduce capture of small immature fish, giving more of them a chance to grow and reproduce.

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Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.

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From guided practice to a new situation

Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.

1 · Guided

Explain how quotas and replanting can work together to conserve a forest.

Give me a hint

One limits removal; the other supports renewal.

Compare my reasoning
  1. A quota limits how many trees may be cut.
  2. Replanting replaces trees and supports regeneration.

Quotas limit the rate or amount of harvesting, while replanting adds trees to support future forest growth. Together they can help balance removal and renewal.

Look for these in your work

  • Quota role stated
  • Replanting role stated
2 · Independent

Name six methods in the fish-stock conservation list and briefly state their roles.

Give me a hint

Recall education, seasons, areas, gear, quotas and monitoring.

Compare my reasoning
  1. Education, closed seasons and protected areas.
  2. Controlled net types and mesh size, quotas and monitoring.

Fish stocks can be conserved using education, closed seasons, protected areas, controlled net types and mesh sizes, quotas and monitoring. Seasons and areas reduce pressure at selected times or places; gear controls select catches; quotas limit removals; monitoring checks the stock.

Look for these in your work

  • Methods named
  • At least two roles explained
3 · Transfer

A fish stock is declining even though there is a catch quota. Suggest two additional methods from the syllabus and explain why they could help.

Give me a hint

Choose controls that protect time, place, fish size or information.

Compare my reasoning
  1. A closed season or protected area can reduce fishing pressure during a period or in a place.
  2. Mesh controls can reduce catching small fish; monitoring can check the trend.

A closed season can reduce pressure during a selected period, and a protected area can create a refuge. Controlled mesh size may let smaller fish escape, while monitoring checks whether the stock continues to decline.

Look for these in your work

  • Two methods selected
  • Purpose tied to decline

Common mistakes

  • Confusing quota with closed season
  • Claiming replanting instantly replaces a mature forest
  • Assuming mesh size affects only adult fish
Recall without your notes

What can you explain now?

Which method limits the amount of timber removed?

Compare with the explanation

A quota

A quota sets a permitted removal limit.

After trying it yourself, choose your next review. This is your self-assessment.

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Make it stick

Compare the forest and fish-stock methods and explain how quotas, protected areas and renewal or breeding protections help.

If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.

Keep learning Sciences — Co-ordinated (Double)

Course scope and assessment

This 2028–2029 pathway maps all 152 detailed subject-content sections in the published 0654 syllabus to original teaching and staged practice. It adapts teaching from the related single-science pathways and excludes clear 0610-only topics such as classification systems, human excretion, tropic responses, food supply, population dynamics, detailed pollution and biotechnology. Some explanations may include wider single-science context. A 0654-specific objective-by-objective review, Core/Supplement audit, human subject-teacher review, supervised laboratory experience and cumulative assessment remain in progress. Written practice is self-checked and does not predict an official grade. The 2025–2027 syllabus has not been reconciled here; choose the 2028–2029 syllabus only.

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