Species Interactions
Species in an ecosystem are constantly interacting with one another and with their environment. These interactions determine which species survive, how populations change over time, and how energy and resources flow through the community.
Species are linked within ecosystems at a number of different levels due to different interactions: competition, predation, mutualism, parasitism and commensalism.
Predation
Species 1 benefits
Species 2 is harmed
This is any interaction between two organisms in which one organism (the predator) consumes all or part of another organism (the prey).
Organisms can be classified as either a predator or a prey.
Competition
Species/Individual 1 is harmed
Species/Individual 2 is harmed
Individuals are competing for space, resources, mates, etc.
Interspecific competition: between members of different species.
Intraspecific competition: between members of the same species.
Symbiosis
Symbiosis describes the close, long-term interaction between two species.
Symbiotic relationships can be obligate (required for survival) or facultative (advantageous without being strictly necessary).
•Mutualism – Both species benefit from the interaction (anemone protects clownfish, clownfish provides faecal matter for food)
•Commensalism – One species benefits, the other is unaffected (barnacles transported to plankton-rich waters by whales)
•Parasitism – One species benefits to the detriment of the other species (ticks or fleas feed on the blood of their canine host)
