What an ecosystem is, its living and non-living parts, producers, consumers and decomposers, food chains and webs, trophic levels, the ten per cent law and biological magnification.
3 lessons, about 1 h 20 min3 simulations10 problems3 practice questionsPython in every lesson
Created by StemPy LabAn ecosystem is all the living things of an area together with the non-living parts of their surroundings. Ponds, forests and grasslands are natural ecosystems; gardens, crop fields and aquariums are made by people. Producers make food, consumers eat it, and decomposers break down dead matter so that nutrients go back to the soil.
A food chain is a series of living things in which each one eats the one before it. Each step is a trophic level: producers first, then herbivores, then carnivores. In nature, many chains link together into a food web, because most animals eat more than one kind of food. Higher levels hold fewer animals.
Green plants capture about one per cent of the sunlight that falls on them. At each step of a food chain only about ten per cent of the energy passes on, and the rest is lost, mostly as heat. So energy flows one way and food chains are short. Harmful chemicals that are not broken down build up along a chain: biological magnification.
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