Symbionts are organisms that feed on... Organisms symbionts

Symbiosis, or mutually beneficial cohabitation between two or more organisms have long been known. But this does not negate the fact that many of the nuances of this phenomenon is still not studied or not well understood.

For the First time is an amazing natural phenomenon discovered by the Swiss scientist Slenderer in 1877. At that time he just examined lichens. To his utter amazement it turned out that these organisms are composite, formed by colonies of fungi and simple unicellular algae. The term "symbiosis" in the scientific literature appeared somewhat later. Rather, it was offered in 1879 de Paris.

With the concept of people figured out relatively quickly, but left the issue of trophic. What do eat some types of symbiotic organisms? In the case of the same lichens was clear that the algae live by photosynthesis, but that's where it receives nutrients fungal component? If you do not know the answer to this question, we offer you to read our article.

General information

Modern scientists have found that the symbionts – organisms that eat (mostly) what consumes the dominant organism. However, it is very rough and not too correct definition, and therefore should describe some of the most interesting cases in more detail.

You should be able to give a few examples yourself. So, helpful bacteria to humans in large numbers are present in acidophilus yogurt. People give this the simplest beautiful living environment, and the bacteria provide the perfect functioning of our gastrointestinal tract.

Recommended

"Knowledge is light and ignorance is darkness": the value, meaning and alternatives

There are some sayings that would seem to need no explanation, such as “teaching & ndash; light and ignorance – darkness”. But some still do not understand their meaning. But not only for such people is written by our article. I...

What was invented by Mendeleev for the army. The history and fate of the invention

D. I. Mendeleev was a brilliant Russian scientist-polymath, who made many important discoveries in various fields of science and technology. Many people know that he is the author of “Fundamentals of chemistry" and the periodic law of chem...

The origin of the Slavs. The influence of different cultures

Slavs (under this name), according to some researchers, appeared in the story only in 6 century ad. However, the language of nationality bears the archaic features of the Indo-European community. This, in turn, suggests that the origin of the Slavs h...

By the way, took advantage of the notorious Kutusov. The symbiosis of culture which he sells, provide a significant improvement in the functioning of the digestive tract even in the elderly, in whom often there are big problems.

Algae as the main symbionts

Biologists have long found that without algae, none of the symbiotic pair of organisms. And it's not only about water but also about the purely terrestrial organisms. They manage to enter into mutually beneficial relationships with each other and with bacteria, fungi, multicellular organisms. You should know that the list of algae that are capable of symbiosis, rather limited.

So, mutually beneficial relationships with fungi are able to establish representatives for a maximum of five to seven families, and historically, that the symbionts are the following: nostok (Nostoc), gleocapsa (Gloeocapsa), scytonema (Scytonema) and stylonema (Stigonema).

About the algae and the sloth

Many people know that in the distant jungle of the Amazon lives the most notable in all respects the animal. It is famous for its slowness and deliberation. Of course, we're talking about sloths. Here only not all know that the coloration of these animals (dirty green, brown) does not appear in the result of the natural pigmentation of the coat, and thanks to the symbiotic algae.

They live in the fur of sloths and feed on the expense of photosynthesis. Sloth is thanks to them that get excellent camouflage colouring. Frankly, scientists have not been able to come to a unanimous conclusion that this coexistence gives to algae. In this case, the symbionts – organisms that feed on substances produced by themselves in photosynthesis.

An Unusual form of the relationship of algae with other organisms

Lichens and sloths-an example of a long-term stable relationship between the two life forms. But not always the symbionts-bacteria and algae form with other organisms as durable and long-lasting unions. So, they often just settle on the surface of a living organism. Of course, a complete symbiosis in this case speech does not go. This phenomenon is called apifilereader. The smallest film of the simplest algae often covers not only the shells of mollusks, but the surface of the body of some aquatic birds and marine animals. Thus, algae-epiphytes in large numbers settle on a giant whale.

Epiphytes – symbionts or parasites?

Scientists still can't agree on what point of view should consider the relationship between the epiphyte and multicellular organism. Some believe that this phenomenon is best taken as primitive, primary version of a symbiotic relationship.

In Fairness, I can agree with this point of view is difficult. Epiphytes don't really cause direct harm to organisms on the surface which they live, and that's the only use (visible anyway) are also observed.

Harm from the epiphytes

Small water insects and mites, whose legs are densely stuck to epiphytes, become extremely slow, since quickly melting, they just physically can't. Higher aquatic plants, the leaves of which “honoured by the attention” single-celled algae, often simply die from lack of sunlight. By the way, that phenomenon probably had every aquarist. We can say that in this case, the symbionts-parasites, as paradoxical as it may sound.

But! The phenomenon of epiphytism studied very, very bad. It is possible that this relationship is actually a benefit not only algae, but also multicellular organisms. The mystery still waits for the researchers. And what we eat symbiotes, if you live inside the cells of the higher animal or plant?

Intracellular symbionts

Is Not so rare symbionts can live inside the cells of his “master”. If talking about the same algae, they are called endophytes. They form endosymbiosis, which is already much more complicated the above phenomena. Between the partners in this case are formed close, lasting and sustainable relationships. Their main difference lies in the fact that identifies these symbionts is simple only due to the detailed and complex cytological studies.

Important! A relatively long time, scientists have proved that the major cellular organelles-the mitochondria in animals and chloroplasts in plants – formed in ancient times thanks to a symbiotic relationship. Once they were independent organisms.

At some point these intracellular symbionts have switched to a completely “settled” existence inside a living cell, and then become dependent on it, passing the management of its genome in its nucleus (in part). So we can safely say that all currently known life forms that tend to be mutually beneficial existence, we have every chance of becoming one with the organisms with which they have today there are partnerships.

How the symbionts penetrate into the cell?

As the organisms are in the cells of higher animals and plants? Some species have specially designed for this mechanism. Often they are not the symbiont, and "receiving party". There is a small water fern-Azolla (Azolla). On the bottom of the cavity it leaves, there are narrow passageways that lead to cavities, specializing in the production of mucus. Here are some of the cavity and fall blue-green algae anabena (Anahaena azollae) that are included in the cavity along with water current.

Fern grows, the channels are overgrown, algae remain in complete isolation. Scientists have long tried to create on the basis of Azolla colonies of other species, but any success they have not achieved. It's safe to say that the formation of a symbiotic relationship is possible only in case of complete coincidence of a number of parameters. In addition, such a Union has pronounced species specificity.

Thus, symbiosis – the organisms that eat the thanks specific to their species (nitrogen fixing microorganisms), share valuable substances with a partner, but require certain conditions that can only provide it.

What is the advantage of this coexistence?

Note that the inside cavities Azolla is a lot of nitrogenous compounds. Blue-green algae that fall into the body of fern, not only actively learn, but also completely lose the ability to fix atmospheric nitrogen. Organisms-symbiosis reciprocate, providing the fern with oxygen and some organic substances.

It Should be noted that these symbionts do not undergo practically no changes in its internal organization. However, the situation is not in all cases of intracellular symbiosis. Often the algae that enter into a mutually beneficial cooperation with other organisms, characterized by a complete reduction of the cell membrane. For example, this occurs in blue-green algae that form a symbiotic relationship with certain species of sea sponges.

Termites, and intracellular symbionts

A Relatively long time, all scientists were in disbelief, reflecting on the digestive processes of termites. How this species manages to flourish, feeding on only one wood? Relatively recently, it was still found that for immediate processing of wood.