Relationships in ecosystems
An ecosystem has two parts: environmental factors (ecotope – climate, soil, water, the non-living part) and the organisms of different populations (biocenosis – the living part: plants, animals, microorganisms). A group of similar individuals of one species is a population; all the populations in an ecosystem form the community. By role, organisms fall into three groups: producers (green plants, algae) make organic matter from inorganic substances by photosynthesis; consumers (all animals) eat ready-made organic matter; reducers (some bacteria and fungi) break dead remains down to minerals and return them to the environment. This way matter circulates. The main relationship between species is “food – eater”: plant and herbivore, predator and prey. For example the fox mostly catches weak or sick hares; so the hare population stays healthy, and the number of foxes depends on the number of hares. If people interfere (hunting many predators, cutting forest) the balance may break.
Role play “Ecosystem”: the class splits into 4 groups – producers (plants), herbivores, predators, reducers. Each group walks with its cards and links to others with “food” threads (coloured string). Then one group “disappears”: which groups are harmed? Safety: play indoors, walking without running or collisions, and never wrap string around necks.