Symbiosis is an interaction between usually two organisms of differing species. Symbiosis can be broken down into various types (Taylor et al, 2010) but for this essay only mutualism, parasitism and commensalism will be reviewed. Mutualism is a relationship formed between two organisms of different species which proves to be beneficial to both. Parasitism is a relationship, usually between two organisms in which one organism benefits greatly (the parasite) and the other is negatively affected (the host). Commensalism: A relationship existing between two organisms which results in one organism benefitting while the other is unaffected.
Mutualism General Example: The Hermit Crab and Sea Anemone. Hermit Crabs have been shown to remove sea anemones and attach them to their shells. Both organisms benefit because the crabs drop food particles in the water when feeding, these food particles are then eaten by the anemones. The crab benefits because if any predator tries to attack, not only can it retract into its shell but the anemone can sting the predator which usually scares it away. Caribbean Example: Ants and Aphids. Aphids when feeding on plants secrete a sweet substance called honeydew, this honeydew is loved by ants and as a result they consume it. In exchange for the honeydew, the ants provide protection for the aphids from predators such as Ladybugs. Both organisms benefit equally from this relationship (2).
Parasitism General Example: Tapeworm and Humans. Tapeworms are parasitic worms from the Class Platyhelminthes. This organism reaches maturity in the gut in which the tapeworm feeds on nutrient rich food which the human has eaten. Mature proglottids of the tapeworm separate from the adult and are expelled in the feces. These feces may be eaten by herbivorous animals such as sheep or cattle which then
References: 1) Taylor, D.J , Green, N. P. O, Stout, G. O, (2010) Biological Science 1&2, Cambridge University Press, Cambridge pp 228-229 2) Herding Aphids: How 'Farmer ' Ants Keep Control Of Their Food http://www.sciencedaily.com/releases/2007/10/071009212548.htm (2007) Distinguish between mutualism, parasitism and commensalism. Give two named examples of each, one of which must be from the Caribbean, citing your sources. Lecturer: Sean Carrington/ Marc Lavoie Name: Javere Brathwaite I.D. 411000563 Course: Biodiversity I Due Date: 15th October, 2012