How Do Organisms Compete and Interact in Communities?
Learn how organisms compete for resources and depend on other species in a community, with clear plant and pollination examples for AQA GCSE Biology.
Organisms compete for limited resources and depend on other species to survive and reproduce. In AQA GCSE Biology, a community is all the populations of different species living in the same habitat. This explanation applies to both Foundation and Higher tier in separate GCSE Biology.
Competition
Competition happens when organisms need the same resource and there is not enough for all of them. Plants often compete for light and space, as well as water and mineral ions from the soil. Animals often compete for food, mates and territory. Members of the same species can compete with one another, but competition can also happen between different species.
For example, if two plants grow close together, the taller plant may receive more light. The shorter plant may photosynthesise less, affecting its growth. In an exam answer, name the resource being competed for and explain how getting less of it affects the organism.
Interdependence
Species in a community also rely on one another for things such as food, shelter, pollination and seed dispersal. This is called interdependence. Bees, for example, feed from flowers and can pollinate them. If fewer bees are available, some plants may produce fewer seeds. That change could then affect animals that depend on those plants for food.
A stable community is one in which species and environmental factors are in balance, so population sizes remain fairly constant. It does not mean the number of organisms never changes.
Common exam mistake: Do not describe every interaction as competition. Organisms may compete for a resource, depend on another species, or do both. Be specific about the resource or relationship in the question.
