Biology (school) · Part 07
Ecosystems and food chains
How living things depend on each other and on their surroundings.
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- EcosystemAll the living things in an area together with their non-living surroundings, such as soil, water and weather.
- HabitatThe place where an organism lives.
- Biotic and abiotic factorsBiotic factors are living things that affect a community, like predators. Abiotic factors are non-living, like temperature and light.
- CompetitionWhen living things use the same limited resources, like food, light, water or mates.
- ProducerAn organism that makes its own food, usually by photosynthesis. Producers are the start of every food chain.
- ConsumerAn organism that gets energy by eating other organisms. Types include primary, secondary and tertiary consumers.
- Food webA diagram of many food chains joined together, showing who eats whom in an ecosystem.
- BiomassThe mass of living material. In a pyramid of biomass, each level has less biomass than the one below it.
- DecomposerA microorganism, mostly bacteria and fungi, that breaks down dead plants and animals and returns nutrients to the soil.
- Carbon cycleHow carbon moves between the air, living things and the ground. Plants take in carbon dioxide and respiration, decay and burning return it.
- Water cycleThe constant movement of water between the sea, air and land by evaporation, condensation and precipitation.