Competition is the process in which organisms compete with one another in order to gain the resources needed for survival. In animals, these resources include mates, food, water, and space; whereas plants compete for light, water, and minerals.

The two common types of competition in ecological systems are intra-specific (competition within a species), and inter-specific (competition between different species). Competition can be further categorised within these two types of competition.

Firstly exploitative competition occurs when one organism’s consumption or depletion of a resource impedes upon another species’ ability to consume a resource, and secondly, interference competition occurring when organisms physically prevent their competition from accessing a certain resource, often through physical violence.

Due to resources often being limited in habitats, one species tends to outcompete another causing a spatial separation to occur. This can be seen in the zonation of the barnacle species Chthamalus and Semibalanus on UK rocky shorelines, with Semibalanus, found to reside in the harsh environment of the high shore as a result of the faster-growing Chthamalus outcompeting it for space downshore, as seen in the figure below. This process of spatially restricting another species through competition is known as competitive exclusion.

NWK competition.png“Untitled”,2002, Graphic, Georgia Tech Prism Web Pages. Source: (Accessed 04/12/2018)

Key Terms

Intra-specific competition – Competition within a species

Inter-specific competition – Competition between different species

Exploitative competition – When one individuals’ use of a resource impedes another individuals’ use of the resource.

Interference competition – When organisms physically prevent their competition from accessing the resource, often through physical violence.

Competitive exclusion – Only one species can exist when two species require approximately the same resources in the same place.

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