Edexcel International GCSE Biology, topic 4
Ecology and the environment
Ecology is the study of how organisms interact with each other and with their environment. This topic covers how populations are studied and what affects them, how energy and substances pass along food chains, how the carbon and nitrogen cycles recycle materials, and how human activities such as pollution and deforestation affect the environment.
Revision notes
Worksheet
FlashcardsSubtopics
Work through them in order. Each one has notes, exam questions and flashcards, and a PDF of each.
- 1The organism in the environment Spec 4.1–4.5Ecological terms, sampling populations with quadrats, biodiversity, and how abiotic and biotic factors affect where organisms live.NotesQuestions 7Flashcards 16
- 2Feeding relationships Spec 4.6–4.9Trophic levels, food chains and webs, pyramids of number, biomass and energy, and why only about 10% of energy passes to the next level.NotesQuestions 7Flashcards 14
- 3Cycles within ecosystems Spec 4.10–4.11BThe carbon cycle with photosynthesis, respiration, decomposition and combustion, and the roles of bacteria in the nitrogen cycle.NotesQuestions 6Flashcards 8
- 4Human influences on the environment Spec 4.12–4.18BPollution by sulfur dioxide, carbon monoxide and sewage, greenhouse gases and global warming, eutrophication, and the effects of deforestation.NotesQuestions 7Flashcards 19
Whole topic
When you have done the subtopics: test yourself on everything, or print the lot.