Common Clownfish (Amphiprion ocellaris) in their magnificent sea anemone (Heteractis magnifica) home.

Symbiosis (pl. symbioses) (from the Greek words syn = con/plus and biono = living) is an interaction between two organisms living together in more or less intimate association or even the merging of two dissimilar organisms. The term host is usually used for the larger (macro) of the two members of a symbiosis. The smaller (micro) member is called the symbiont (alternately, symbiote). When a microscopic symbiont lives inside its host's cells, it is referred to as an endosymbiont. Common Clownfish (Amphiprion ocellaris) in their Magnificent Sea Anemone (Heteractis magnifica) home. ... Common Clownfish (Amphiprion ocellaris) in their Magnificent Sea Anemone (Heteractis magnifica) home. ... Species Twenty-seven, including: Amphiprion allardi - Allards Clownfish Amphiprion melanopus - Cinnamon Clownfish Amphiprion clarkii - Clarks Anemonefish Amphiprion ocellaris - Ocellaris Clownfish Amphiprion percula - Percula Clownfish Amphiprion perideraion - Pink Skunk Clownfish Amphiprion polymnus - Saddleback Clownfish Amphiprion sebae - Sebae Clownfish Amphiprion tricinctus - Three-Band Anemonefish Amphiprion ephippium - Tomato Clownfish Amphiprion frenatus... Biological interactions result from the fact that organisms in an ecosystem interact with each other, in the natural world, no organism is an autonomous entity isolated from its surroundings. ... An endosymbiont (also known as intracellular symbiont) is any organism that lives within cells of another organism, i. ...

The various forms of symbiosis include: -

• parasitism, in which the association is disadvantageous or destructive to one of the organisms and benefitial to the other (+ -)
• mutualism, in which the association is advantageous to both (+ +)
• commensalism, in which one member of the association benefits while the other is not affected (+ 0)
• amensalism, in which the association is disadventageous to one member while the other is not affected (- 0)

In some cases, the term symbiosis is used only if the association is obligatory and benefits both organisms. Symbiosis as defined in this article does not restrict the term to only the mutually beneficial interactions. Parasitism (in Greek: παρασσυτισμός) is an interaction between two organisms, in which one organism (the parasite) benefits and the other (the host) is harmed. ... Mutualism is also the form of Anarchism described by Pierre-Joseph Proudhon . In biology, mutualism is an interaction between two species in which both organisms derive some degree of benefit. ... In ecology, commensalism is an interaction between two living organisms, where one creature benefits and the other is neither harmed nor helped. ... Amensalism is an interaction between two species where one impedes or restricts the success of the other while not being affected, positively or negatively, by the presence of the other. ...

Symbiosis may be divided into two distinct categories: ectosymbiosis and endosymbiosis. In ectosymbiosis, the symbiont lives on the body surface of the host, including the inner surface of the digestive tract or the ducts of exocrine glands. In endosymbiosis, the symbiont lives in the intracellular space of the host. Ectosymbiosis is symbiosis in which the symbiont lives on the body surface of the host, including internal surfaces such as the lining of the digestive tube and the ducts of glands. ... An endosymbiont (also known as intracellular symbiont) is any organism that lives within cells of another organism, i. ... Exocrine gland refers to glands that secrete their products via a duct. ...

An example of mutual symbiosis is the relationship between clownfish of the genus Amphiprion (family, Pomacentridae) that dwell among the tentacles of tropical sea anemones. The territorial fish protects the anemone from anemone-eating fish, and in turn the stinging tentacles of the anemone protect the anemone fish from its predators (a special mucus on the anemone fish protects it from the stinging tentacles). Species Twenty-seven, including: Amphiprion allardi - Allards Clownfish Amphiprion melanopus - Cinnamon Clownfish Amphiprion clarkii - Clarks Anemonefish Amphiprion ocellaris - Ocellaris Clownfish Amphiprion percula - Percula Clownfish Amphiprion perideraion - Pink Skunk Clownfish Amphiprion polymnus - Saddleback Clownfish Amphiprion sebae - Sebae Clownfish Amphiprion tricinctus - Three-Band Anemonefish Amphiprion ephippium - Tomato Clownfish Amphiprion frenatus... Species Twenty-seven, including: Amphiprion allardi - Allards Clownfish Amphiprion melanopus - Cinnamon Clownfish Amphiprion clarkii - Clarks Anemonefish Amphiprion ocellaris - Ocellaris Clownfish Amphiprion percula - Percula Clownfish Amphiprion perideraion - Pink Skunk Clownfish Amphiprion polymnus - Saddleback Clownfish Amphiprion sebae - Sebae Clownfish Amphiprion tricinctus - Three-Band Anemonefish Amphiprion ephippium - Tomato Clownfish Amphiprion frenatus... Genera Many, e. ... Families Many, see text. ...

Some goby fish species live in symbiosis with a shrimp.

Another example is the goby fish, which sometimes lives together with a shrimp. The shrimp digs and cleans up a burrow in the sand in which both the shrimp and the goby fish live. The shrimp is almost blind leaving it vulnerable to predators when above ground. In case of danger the goby fish touches the shrimp with its tail to warn it of imminent danger. When that happens both the shrimp and goby fish quickly retract into the burrow. Download high resolution version (802x660, 166 KB)Goby fish and shrimp in front of their burrow. ... Download high resolution version (802x660, 166 KB)Goby fish and shrimp in front of their burrow. ... Genera Many, e. ... Suborders Not necessary complete list: Aristeidae Penaeidae Sergestidae Sicyoniidae Solenoceridae Nematocarcinidae Atyidae Pasiphaeoidae Rhynocinetidae Campylonotidae Palaemonidae Alpheidae Ogyrididae Hippolytidae Proussidae Pandalidae Crangonidae True shrimp are small, swimming, decapod crustaceans usually classified in the suborder Natantia, found widely around the world in both fresh and salt water. ... Genera Many, e. ... Suborders Not necessary complete list: Aristeidae Penaeidae Sergestidae Sicyoniidae Solenoceridae Nematocarcinidae Atyidae Pasiphaeoidae Rhynocinetidae Campylonotidae Palaemonidae Alpheidae Ogyrididae Hippolytidae Proussidae Pandalidae Crangonidae True shrimp are small, swimming, decapod crustaceans usually classified in the suborder Natantia, found widely around the world in both fresh and salt water. ...

A famous land version of symbiosis is the relationship of the Egyptian Plover bird and the crocodile. In this relationship, the bird is well known for preying on parasites that feed on crocodiles which are potentially harmful for the animal. To that end, the crocodile openly invites the bird to hunt on his body, even going so far as to open the jaws to allow the bird enter the mouth safely to hunt. For the bird's part, this relationship not only is a ready source of food, but a safe one considering that few predator species would dare strike at the bird at such close proximity to its host. Binomial name Pluvianus aegyptius (Linnaeus, 1758) The Egyptian Plover, Pluvianus aegyptius, is a wader in the pratincole and courser family, Glareolidae. ... Genera Crocodylus Osteolaemus Tomistoma A crocodile can be any of the 14 species of large, water-loving reptiles in the family Crocodylidae (sometimes classified instead as the subfamily Crocodylinae). ... A parasite is an organism that lives in or on the living tissue of a host organism at the expense of it. ...

The biologist Lynn Margulis, famous for the work on endosymbiosis, contends that symbiosis is a major driving force behind evolution. She considers Darwin's notion of evolution, driven by competition, as incomplete, and claims evolution is strongly based on co-operation, interaction, and mutual dependence among organisms. According to Margulis and Sagan (1986), "Life did not take over the globe by combat, but by networking". As in humans, organisms that cooperate with others of their own or different species often outcompete those that don't. Lynn Margulis (born 1938) is a biologist and a professor at the University of Massachusetts Amherst. ... An endosymbiont (also known as intracellular symbiont) is any organism that lives within cells of another organism, i. ... Charles Darwin, the father of evolutionary theory Although generally, evolution is taken to mean any process of change over time, in the context of life science, evolution is a change in the traits of living organisms over generations, including the emergence of new species. ... Competition characterises a biochemical, ecologic, economic, political, or sporting activity whereby two or more individuals or groups strive antagonistically against one another for some reward. ... Co-operation refers to the practice of people or greater entities working in common with commonly agreed-upon goals and possibly methods, instead of working separately in competition. ... Generally, an interaction is a kind of action which occurs as two or more objects have an effect upon one another. ...

However, mutualism, parasitism, and commensalism are often not discrete categories of interactions and should rather be perceived as a continuum of interaction ranging from parasitism to mutualism. In fact, the direction of a symbiotic interaction can change during the lifetime of the symbionts due to developmental changes as well as changes in the biotic/abiotic environment in which the interaction occurs.

See also

• List of symbiotic relationships

This is an incomplete list of notable mutualistic symbiotic relationships, in which different species have a cooperative or mutually dependent relationship. ... In biology, a species is a kind of organism. ... Biological interactions result from the fact that organisms in an ecosystem interact with each other, in the natural world, no organism is an autonomous entity isolated from its surroundings. ... Ecology can mean either: the natural environment, or an analysis or study using the principles and methods of ecological science. ... Amensalism is an interaction between two species where one impedes or restricts the success of the other while not being affected, positively or negatively, by the presence of the other. ... In ecology, commensalism is an interaction between two living organisms, where one creature benefits and the other is neither harmed nor helped. ... Mutualism is also the form of Anarchism described by Pierre-Joseph Proudhon . In biology, mutualism is an interaction between two species in which both organisms derive some degree of benefit. ... Neutralism describes the relationship (or lack thereof) between two species which do not interact with or affect each other. ... Predation is an interaction between organisms (animals) in which one organism captures and feeds upon another called the prey. ... Carnivores are animals that eat a diet consisting mostly of meat. ... In zoology, an herbivore is an animal that is adapted to eat primarily plants (rather than meat). ... Parasitism (in Greek: παρασσυτισμός) is an interaction between two organisms, in which one organism (the parasite) benefits and the other (the host) is harmed. ... Parasitoids differ from parasites in their relationship with the host. ... Competition characterises a biochemical, ecologic, economic, political, or sporting activity whereby two or more individuals or groups strive antagonistically against one another for some reward. ...

References

• Lynn Margulis and Dorion Sagan, Microcosmos: Four Billion Years of Evolution from Our Microbial Ancestors. Summit Books, New York, 1986. ISBN 0520210646
• Jan Sapp Evolution by Association, Oxford University Press, 1994. ISBN 0195088212