An ecosystem is a community of living things and the non-living environment they depend on. In IGCSE Geography you are asked to link climate, vegetation and soil, read food-web and land-cover data, explain how a disturbance spreads, and judge conservation evidence.
This module sits inside the wider Geography learning guide. It builds on weather and climate, because temperature and rainfall set the conditions for every ecosystem.
What do you need before you start?
You need to read a table and a simple chart, work out a percentage change and write a sentence of cause and effect. The arithmetic stays at IGCSE level. Check the Cambridge syllabus page for your exam year, because the exact content and skills can change between series.
One orienting example
All numbers here are invented for practice. A forest area covered 5,000 km² in the first survey and 4,000 km² in the second. The change is 4,000 − 5,000 = −1,000 km², and the percentage change is −1,000 ÷ 5,000 × 100 = −20%.
Now add the geography. If the loss came from clearing the canopy, more rain reaches bare soil, runoff increases and nutrients wash away. A number only becomes a geographical answer once you explain what caused it and what follows.
In what order should you study the lessons?
- Link climate, vegetation and soil in a model first, because every later lesson reuses that chain.
- Interpret a food-web or land-cover dataset next, to turn energy flows and area figures into statements you can defend.
- Explain a disturbance with a causal chain after that, to practise linking each step to the next.
- Evaluate conservation evidence with limitations once you can read data, so you can say how far it supports a claim.
- Avoid ecological or demographic stereotypes last, because it asks you to describe places and people fairly using everything above.
What are the common traps?
- Saying lush vegetation means fertile soil, when in a rainforest most nutrients are held in the plants.
- Mixing up a percentage change with a change in percentage points.
- Listing effects of a disturbance without words that connect them.
- Treating a rise after protection as proof that the protection worked.
- Describing every place or group with one general label.
How should you use the practice set?
Work through the ecosystems and environmental change practice set with a pencil and calculator, and cover the answers until you have written your own. The statistics and distribution explorer helps with averages and percentages, and the food-web and energy-flow explorer shows how energy moves between levels. Record repeated slips in the mistake log and retest queue.
Real case studies are not invented here. When you build notes on one, write down the place, date and source for each fact, and describe events neutrally and factually.
Fieldwork and the alternative-to-fieldwork route are set by your course and exam centre, and the Cambridge page sets out what is assessed. Our online lessons focus on the data and written-answer skills around them, described on the Geography tuition page.