Navigation Links
Symbiosis



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.

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.

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.

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).


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.

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.

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.

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

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


'"/>


(Date:4/17/2015)... , April 17, 2015 ... security concerns, and technological advancement to drive biometric ... until 2020   According to ... Arabia Biometric Systems Market Forecast &  Opportunities, 2020 ", biometric systems market ... projected to register growth at CAGR of over ...
(Date:4/10/2015)... Research and Markets ( http://www.researchandmarkets.com/research/cjk4gb/security ... Competitive Profiles - NEC" report to their offering. ... will continue to supply a range of IT security ... company focus on the development of a Big Data ... in the Asia-Pacific region is ...
(Date:4/2/2015)... At its 2015 ACMG Annual Clinical Genetics ... the American College of Medical Genetics and Genomics (ACMG) ... Board.  Members of the ACMG Board of Directors serve ... advancing its policies and programs. ACMG is the national ... an eventful time in medical genetics and genomics.  We ...
Breaking Biology News(10 mins):Saudi Arabia Biometric Systems Market to Grow at 22% Through 2020, Says TechSci Research 2Saudi Arabia Biometric Systems Market to Grow at 22% Through 2020, Says TechSci Research 3NEC Security Competitive Profile 2015 2American College of Medical Genetics and Genomics Announces New Board Members: Dr. Louanne Hudgins is ACMG President-Elect 2American College of Medical Genetics and Genomics Announces New Board Members: Dr. Louanne Hudgins is ACMG President-Elect 3American College of Medical Genetics and Genomics Announces New Board Members: Dr. Louanne Hudgins is ACMG President-Elect 4American College of Medical Genetics and Genomics Announces New Board Members: Dr. Louanne Hudgins is ACMG President-Elect 5American College of Medical Genetics and Genomics Announces New Board Members: Dr. Louanne Hudgins is ACMG President-Elect 6American College of Medical Genetics and Genomics Announces New Board Members: Dr. Louanne Hudgins is ACMG President-Elect 7American College of Medical Genetics and Genomics Announces New Board Members: Dr. Louanne Hudgins is ACMG President-Elect 8
... California, Davis , who discovered a novel therapeutic target ... grant from the American Asthma , Foundation to investigate ... chronic disease affecting 300 million people worldwide, including 23 ... to evaluate whether the new field of , metabolomics ...
... process of domestication, humans would still be hunters and ... Fortunately, for all of us who do not relish ... and berries, early civilizations successfully cultivated many species of ... studies of the domestication of various species provide a ...
... Ore. Particulate air pollution during the 2008 Olympic ... the World Health Organization, was far worse than other ... than has been reported by Chinese environmental experts ... problem. The weather, in fact, turned out to ...
Cached Biology News:UC Davis grant zeroes in on novel asthma diagnosis and treatment 2UC Davis grant zeroes in on novel asthma diagnosis and treatment 3Domestication of Capsicum annuum chile pepper provides insights into crop origin and evolution 2Athletes, spectators faced unprecedented air pollution at 2008 Olympic Games 2Athletes, spectators faced unprecedented air pollution at 2008 Olympic Games 3
Other biology definitionOther Tags