20.1.5Human Influences on Ecosystems
Sustainability — Cambridge IGCSE Biology 0610 Revision Notes & Topical Questions
5 min read 5 parts Lesson 6 of 7 Unit quiz
Curriculum Equation Key قوانين الرقم الهيدروجيني والاتزان الأيوني - pH & Acid-Base Equilibrium FormulasFast Exam Solution
pH = -log[H⁺] | pOH = -log[OH⁻] | pH + pOH = 14 | [H⁺][OH⁻] = 10⁻¹⁴
Word Equation & Conditions: الرقم الهيدروجيني = -لوغاريتم تركيز أيون الهيدروجين | pH + pOH = 14
Location & Specifications: الاتزان الأيوني، كيمياء 3 ثانوي، التحصيلي، و AP Chemistry.
Section 1 of 5Sustainable and Non-Renewable Resources
Whether a resource lasts depends on how quickly it is replaced compared with how quickly it is used.
Sustainable resource
- Sustainable resource A resource that is produced or replaced as fast as it is removed,
- so it does not run out; managed forests and fish stocks can be examples.
Non-renewable resource
- Non-renewable resource Fossil fuels such as coal, oil and natural gas cannot be replaced on a human timescale once they have been burned.
Raw material use
- Raw material use Oil is also the starting material for almost all plastics, so using it as fuel removes it from other uses.
Reuse and recycling
- Reuse and recycling Recycling paper, plastic, glass and metal reduces waste and cuts the raw materials and energy needed to make new products.
Reducing demand
- Reducing demand Conserving non-renewable resources means using less of them and switching to sustainable alternatives wherever possible.
| Resource | Renewable if managed? | Main way to protect it |
|---|---|---|
| Timber and paper | Yes | Replant trees as mature ones are cut |
| Fish stocks | Yes | Limit catches so breeding continues |
| Fossil fuels | No | Use less and develop alternatives |
Section 2 of 5Sustaining Forests
Forests supply timber and paper, so replacing what is felled keeps the supply going.
1
Much paper is made from plantation forests in which new trees are replanted when mature trees are harvested.
2
Tropical hardwoods such as teak and mahogany regrow slowly but are in high demand for furniture, so over-felling is a danger.
3
Schemes such as the Forest Stewardship Council monitor logging companies and track timber so buyers can choose responsibly sourced wood.
4
Education makes logging companies aware of sustainable practice and teaches consumers to look for products from sustainable sources.
Section 3 of 5Sustaining Fish Stocks
Overfishing removes breeding fish faster than they can be replaced, so catches are controlled.
Sustaining Fish Stocks
Quotas
- Quotas Limiting the number of fish that may be caught each year stops the population being driven down.
Net mesh size
- Net mesh size Controlling the size of fish caught lets young fish escape and grow to breeding age.
Closed seasons
- Closed seasons Banning fishing when fish gather in large numbers to breed prevents the loss of whole breeding groups.
Protected areas
- Protected areas Restricting fishing in particular zones lets stocks recover and supplies the surrounding waters.
Section 4 of 5Sustainable Development (Extended)
Sustainable development meets the needs of a growing human population without harming the environment.
Local versus commercial
- Local versus commercial Local people need to use nearby resources,
- while large companies want profit from forests and fish,
- and these aims can conflict.
Humans versus wildlife
- Humans versus wildlife Taking resources can destroy habitats,
- so human needs must be balanced against the survival of the plants and animals living there.
Present versus future
- Present versus future Catching all the fish needed today may deplete stocks so that future generations have none.
Cooperation
- Cooperation Planning and managing resources needs agreement at local, national and international levels.
Section 5 of 5Exam Checklist & Tips
20.1.5 – Key Points for the Exam
- Sustainable resource A resource replaced as quickly as it is removed, so it does not run out.
- Non-renewable A resource that cannot be replaced once used, such as a fossil fuel.
- Overfishing Catching fish faster than the population can replace them.
- Sustainable development Meeting the needs of an increasing human population without harming the environment.
- Quota A fixed limit on the amount that may be caught or harvested.
Common Mistakes
- Calling all forests sustainable;
- only forests where felled trees are replaced and monitored count as sustainable sources.
- Thinking recycling makes a non-renewable resource renewable; it only reduces how fast it is used up.
- Giving only one reason for fishing controls;
- link quotas, mesh size and closed seasons to protecting breeding fish.
- Describing sustainable development as stopping all use of resources instead of balancing present, future and wildlife needs.
Last updated:
\n