Cambridge IGCSE Biology, topic 20
Human influences on ecosystems
Humans change ecosystems when they grow food, build, extract resources and release waste. This topic looks at how farming raises food production and what it costs, why habitats are destroyed, how pollution damages water, land and air, and how conservation tries to protect species and resources for the future.
Revision notes
Worksheet
FlashcardsSubtopics
Work through them in order. Each one has notes, exam questions and flashcards, and a PDF of each.
- 1Food supply Spec 20.1How farming methods raise food production, and the advantages and disadvantages of monocultures and intensive livestock production.NotesQuestions 6Flashcards 6
- 2Habitat destruction Spec 20.2Biodiversity, why habitats are destroyed, how humans damage food webs, and the effects of deforestation.NotesQuestions 6Flashcards 5
- 3Pollution Spec 20.3The effects of sewage, fertiliser, eutrophication, plastics, methane and carbon dioxide on ecosystems and climate.NotesQuestions 6Flashcards 8
- 4Conservation Spec 20.4Sustainable resources, why species become endangered, and how forests, fish stocks and endangered species are conserved.NotesQuestions 8Flashcards 12
Whole topic
When you have done the subtopics: test yourself on everything, or print the lot.