Edexcel IGCSE Biology topic guide
Ecology and the environment questions
Explore how organisms interact with one another and their environment, from food webs to the effects of pollution.
Ecology and the environment topic overview
Ecology and the environment explores populations, communities, food relationships, nutrient cycles and the effects of human activity on ecosystems.
Read ecological data and sampling methods carefully, trace matter and energy through the system, and support environmental conclusions with evidence from the question.
Question types in ecology and the environment
- Quadrat, transect and population-sampling practical questions.
- Food-chain, food-web, pyramid and energy-transfer interpretation.
- Carbon-cycle, nitrogen-cycle and decomposition explanations.
- Evaluation of pollution, climate change, conservation and food-security strategies.
Ecology and the environment subtopics
Choose a subtopic for its syllabus points, answering guidance and worked exam questions.
4.a The organism in the environment
Habitats, populations, sampling methods and the factors that affect where organisms live.
4.b Feeding relationships
Food chains, food webs, ecological pyramids and energy transfer between trophic levels.
4.c Cycles within ecosystems
Carbon and nitrogen cycles, decomposition and the roles of microorganisms.
4.d Human influences on the environment
Air and water pollution, greenhouse gases, deforestation and conservation.