Two organisms which live in close intimate proximity to each other. Larger organism is usually deemed the host Smaller organism is usually deemed to symbiote Where you have Ectosymbiosis: Symbiote lives outside or in the digestive tract of another organism (digestive tracts are technically outside of almost every vertebrate on the planet). Endosymbiosis: organism lives intracellularly or extracellulary

Mutualism: in which the association is advantageous to both (+ +) The territorial clown fish protects the anemone from anemone-eating fish, and in turn the stinging tentacles of the anemone protect the clownfish from its predators (a special mucus on the clownfish protects it from the stinging tentacles).

Commensalism: in which one member of the association benefits while the other is not affected (+ 0) Epiphyte growing on a tree. The epiphyte uses the tree to collect water and minerals between crevices in bark and most importantly get elevated to collect UV light. Tree does not benefit or get harmed by the epiphyte

Air pollution caused by automobiles, electricity generating stations, or metal smelters often causes severe damage to lichens and plants in the affected area. Lichen dies and we don’t benefit from its death Amensalism: in which the association is disadvantageous to one member while the other is not affected (− 0)

Parasitism: in which the association is disadvantageous or destructive to one of the organisms and beneficial to the other (+ −) Electron microscopy of tape worm Rostellum Tape Worm Which is approximately 14 feet long Tape worm which was pulled out of a human patient X-Ray photograph showing a tape worm growing throughout the small intestine of a human host Tape worm eggs or Proglottids

The normal incubation period of onchocerciasis ranges from nine to 24 months after the bite of an infected black fly. Each female worm can reproduce millions of microfilaria during her lifetime. Worms can live for years. Onchocerciasis is an infection caused by the parasite Onchocerca volvulus (worm), spread by the bite of an infected blackfly. Also called River Blindness because the transmission is most intense in remote African rural agricultural villages, located near rapidly flowing streams. Persons with heavy infections will usually have one or more of the three conditions; dermatitis, eye lesions, and/or subcutaneous nodules. Mature worm in cyst and a blinded adult male Microfilaria which is deposited by black fly

There is a real continuum, take the barnacle on the whale below…mutualism, commensalism, amensalism or parasitism?