Every adult remembers from school biology course, that such a symbiosis.Or at least I heard of the word.However, not everyone knows that the most common example of symbiosis is a couple of people - lactic acid bacteria.In fact, the symbiosis - is any form of relationship between two living organisms that have different genotypes and proiskhozhdzhenie in which they co-exist as a single system.But we should not confuse the symbiosis with parasitism, as often happens.
In nature, there are the following types of symbiosis: the aforementioned parasitism (type of relationship, useful to one partner, and hurtful to another), mutualism (mutually beneficial relationship), commensalism (relations beneficial to one partner, and indifferent to the other), and amensalizm (relationships that are harmful to onehand and indifferent for the second).In addition, modern science is accepted to allocate symbiogenesis or endosymbiosis, which is an intracellular symbiosis: one organism lives inside the cells of another.Organisms in a symbiotic relationship, called symbionts.
In order to understand what is the symbiosis, it is first necessary to consider the earliest form of it, namely symbiogenesis.Scientists have proved that cellular organelles mitochondria and plastids were previously some ancient organisms: the mitochondria were prokaryotic bacteria and plastids - autotrophic bacteria that settled in the simplest eukaryotic cells.Initially it was typical of the type of symbiosis mutualism, ie, mutually beneficial relationship.Then, these organisms are so merged that have become a common structure that eventually stuck genetically.
By the same principle under construction and all other kinds of symbiotic relationships.The easiest way to imagine that such a symbiosis, the classic example of lichens.This type of relationship should be viewed as mutualism, as the fungus receives from cyanobacteria nutrients synthesized by the latter, and, in turn, creates a bacteria friendly environmental conditions, protect from drying, ultraviolet radiation and other adverse environmental factors, and also makes possible the existence ofa substrate having an acidic pH.
parasitism - as a type of symbiosis.A classic example of it are considered to be all eukaryotic infectious agents, including fungi.In these respects the parasite lives in the body of the host, feeds its resources.There are obligate (DC) and optional (periodic) parasitism.The former include viruses, to the second - lice, worms and others.
example of mutualism is the above-mentioned pair of man-intestinal microflora.
As part of commensalism to distinguish between many subspecies: zoochory (distribution of parts of the plant, serving for reproduction by animals) - these are birds that eat seeds or carrying them on their legs), sinoykiya (use one body home another without causing damage to the first,for example, fish, spawn in the shells of mollusks).Not to be confused with Inquiline - using a home owner with the destruction of the latter, such as insects, larvae otklydyvayuschie in the shells of mollusks, or Gauls, while destroying the host.
amensalizma The most common example is the relationship of the tree and moss that grows underneath.Moss is experiencing the negative effect of such symbiosis (lack of light, nutrients, water, etc.), And tree care.
Thus, using relatively simple and striking examples will illustrate that this symbiosis, and not to be confused with commensalism mutualism and parasitism.
