Topic 19 of 21 · 4 modules planned

Organisms and their environment

Food chains, energy flow, nutrient cycles and how populations grow.

Modules

Module 1 · syllabus 19.2
Food chains and webs
What happens to a food web when one species disappears?
This module is planned. It will have readings, an experiment, practice with self-checks and a final check.

Syllabus statements for this topic · for teachers · 31 statements

Core for every pupil · Supplement also for Extended entry. Paraphrased from the Cambridge IGCSE Biology 0610 syllabus (2026–2028); check the official syllabus for exact wording.

19.1 Energy flow

19.1.1Sun as the main energy source for lifeC
19.1.2Energy flow through organisms to the environmentC

19.2 Food chains and food webs

19.2.1Food chains transfer energyC
19.2.2Construct and interpret food chainsC
19.2.3Food websC
19.2.4ProducersC
19.2.5ConsumersC
19.2.6Primary to quaternary consumersC
19.2.7HerbivoresC
19.2.8CarnivoresC
19.2.9DecomposersC
19.2.10Human impact: overharvesting and introduced speciesC
19.2.11Pyramids of numbers and biomassC
19.2.12Why use a pyramid of biomassC
19.2.13Trophic level definedC
19.2.14Name trophic levels in chains, webs, pyramidsC
19.2.15Pyramids of energyS
19.2.16Why use a pyramid of energyS
19.2.17Energy transfer between levels is inefficientS
19.2.18Why food chains rarely exceed five levelsS
19.2.19Eating crops is more energy efficientS

19.3 Nutrient cycles

19.3.1Carbon cycleC
19.3.2Nitrogen cycleS
19.3.3Microorganisms in the nitrogen cycleS

19.4 Populations

19.4.1PopulationC
19.4.2CommunityC
19.4.3EcosystemC
19.4.4Factors affecting population growth rateC
19.4.5Phases of the sigmoid growth curveC
19.4.6Interpret population growth graphsC
19.4.7Explain each phase of the sigmoid curveS