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Without which digestion would be impossible, to plants (an example is some orchids, whose pollen can only be distributed by one, certain kind insects). Such relationships are always successful when they increase the chances of both partners to survive. The actions carried out in the course of symbiosis or the substances produced are essential and irreplaceable for the partners. In a generalized sense, such a symbiosis - intermediate between interaction and fusion.
This theory easily explains the existence of a bilayer membrane. The inner layer originates from the membrane of the engulfed cell, while the outer layer is part of the membrane of the engulfed cell wrapped around the alien cell. It is also well understood that the presence of mitochondrial DNA is nothing more than remnants of the alien cell's DNA. So, many of the organelles of the eukaryotic cell at the beginning of their existence were separate organisms, and about a billion years ago they combined their efforts to create cells of a new type. Therefore, our own bodies are an illustration of one of the oldest partnerships in nature.
It should also be remembered that symbiosis is not only coexistence different types living organisms. At the dawn of evolution, symbiosis was the engine that brought unicellular organisms of the same species into one multicellular organism (colony) and became the basis for the diversity of modern flora and fauna.
Examples of symbiosis
- Endophytes live inside the plant, feed on its substances, while releasing compounds that promote the growth of the host organism.
- Transportation of plant seeds by animals that eat the fruit and excrete the undigested seeds along with the droppings elsewhere.
insects/plants
mushrooms/algae
- A lichen is composed of a fungus and an algae. As a result of photosynthesis, algae produce organic substances (carbohydrates) that are used by the fungus, which supplies water and minerals.
Animals/Algae
mushrooms/plants
- Many mushrooms come from a tree nutrients and supply it with minerals (mycorrhiza).
insects/insects
- Some ants protect ("graze") aphids and receive from it in return a secretion containing
Can spread only one, certain type of insect. Such relationships are always successful when they increase the chances of both partners to survive. The actions carried out in the course of symbiosis or the substances produced are essential and irreplaceable for the partners. In a generalized sense, such a symbiosis is an intermediate link between interaction and merging.
A kind of symbiosis is endosymbiosis (see Symbiogenesis), when one of the partners lives inside the cell of the other.
The science of symbiosis is symbiology.
Mutualism
Mutually beneficial relationships can be formed on the basis of behavioral responses, for example, as in birds that combine their own food with the distribution of seeds. Sometimes mutualistic species enter into close physical interaction, as in the formation of mycorrhiza (fungal root) between fungi and plants.
The close contact of species in mutualism causes their joint evolution. A typical example is the mutual adaptations that have developed between flowering plants and their pollinators. Mutualist species often co-populate.
Commensalism
Depending on the nature of the relationship of commensal species, three types are distinguished:
- the commensal is limited to the use of the food of an organism of another species (for example, an annelids from the genus Nereis lives in the coils of the shell of a hermit crab, feeding on the remnants of the food of the crab);
- the commensal is attached to the organism of another species, which becomes the "master" (for example, a fish stuck with a sucker fin attaches to the skin of sharks and other large fish, moving with their help);
- commensal settles in the internal organs of the host (for example, some flagellates live in the intestines of mammals).
An example of commensalism is legumes (for example, clover) and cereals growing together on soils poor in available nitrogen compounds, but rich in potassium and phosphorus compounds. Moreover, if the cereal does not suppress the legume, then it, in turn, provides it with an additional amount of available nitrogen. But such a relationship can only last as long as the soil is poor in nitrogen and the grasses cannot grow strongly. If, as a result of the growth of legumes and the active work of nitrogen-fixing nodule bacteria a sufficient amount of nitrogen compounds available for plants accumulates in the soil, this type of relationship is replaced by competition. Its result, as a rule, is the complete or partial displacement of less competitive legumes from the phytocenosis. Another variant of commensalism: one-sided help of a “nanny” plant to another plant. So, birch or alder can be a nanny for spruce: they protect young spruces from direct sun rays, without which a spruce cannot grow in an open place, and also protect the seedlings of young Christmas trees from squeezing them out of the soil by frost. This type of relationship is typical only for young spruce plants. As a rule, when the spruce reaches a certain age, it begins to behave like a very strong competitor and suppresses its nannies.
Shrubs from the families of labiales and Asteraceae and South American cacti are in the same relationship. Possessing a special type of photosynthesis (CAM metabolism), which occurs during the day with closed stomata, young cacti become very overheated and suffer from direct sunlight. Therefore, they can develop only in the shade under the protection of drought-resistant shrubs. There are also numerous examples of symbiosis that is beneficial to one species and does not bring any benefit or harm to another species. For example, the human intestine is inhabited by many types of bacteria, the presence of which is harmless to humans. Similarly, plants called bromeliads (which include, for example, pineapple) live on the branches of trees, but get their nutrients from the air. These plants use the tree for support without depriving it of nutrients. Plants make their own nutrients, they don't get them from the air.
Commensalism way coexistence two different species of living organisms, in which one population benefits from the relationship, while the other receives neither benefit nor harm (for example, common silverfish and humans).
Symbiosis and evolution
In addition to the nucleus, eukaryotic cells have many isolated internal structures called organelles. Mitochondria, one type of organelle, generate energy and are therefore considered the powerhouses of the cell. Mitochondria, like the nucleus, are surrounded by a bilayer membrane and contain DNA. On this basis, a theory has been proposed for the emergence of eukaryotic cells as a result of symbiosis. One of the cells absorbed the other, and then it turned out that together they cope better than individually. This is the endosymbiotic theory of evolution.
This theory easily explains the existence of a bilayer membrane. The inner layer originates from the membrane of the engulfed cell, while the outer layer is part of the membrane of the engulfed cell wrapped around the alien cell. It is also well understood that the presence of mitochondrial DNA is nothing more than remnants of the alien cell's DNA. So, many (perhaps all) of the eukaryotic cell organelles at the beginning of their existence were separate organisms, and about a billion years ago they joined forces to create a new type of cell. Therefore, our own bodies are an illustration of one of the oldest partnerships in nature.
It should also be remembered that symbiosis is not only the coexistence of different types of living organisms. At the dawn of evolution, symbiosis was the engine that brought unicellular organisms of the same species into one multicellular organism (colony) and became the basis for the diversity of modern flora and fauna.
Examples of symbioses
- Endophytes live inside the plant, feed on its substances, while releasing compounds that promote the growth of the host organism.
- Transportation of plant seeds by animals that eat the fruits and excrete the undigested seeds along with the droppings elsewhere.
insects/plants
mushrooms/algae
- A lichen is composed of a fungus and an algae. As a result of photosynthesis, algae produce organic substances (carbohydrates) that are used by the fungus, which supplies water and minerals.
Animals/Algae
mushrooms/plants
- Many fungi receive nutrients from the tree and supply it with minerals (mycorrhiza).
insects/insects
- Some ants protect ("herd") aphids and receive sugar-containing secretions from them in return.
see also
Notes
Literature
- Margelis L. The role of symbiosis in cell evolution. - M: Mir, 1983. - 354 p.
- Douglas A.E Symbiotic interaction. - Oxford University. Press: Oxford:Y-N, Toronto, 1994. - 148 p.
Links
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Synonyms:- (from Greek symbiosis cohabitation), close cohabitation of organisms of two or more species, which, as a rule, has become necessary and beneficial for both partners (symbionts). Symbiosis in marine animals was discovered by K. Möbius (1877). According to the degree of connection ... Ecological dictionary
symbiosis- a, m. symbiose f. gr. symbiosis. biol. The cohabitation of organisms of different species, usually bringing them mutual benefit, for example. fungus and algae that together form a lichen. SIS 1954. Symbiosis of hermit crab and sea anemone. BAS 1. Vinogradov completed ... ... Historical Dictionary of Gallicisms of the Russian Language
Mutualism
Mutualism is a mutually beneficial cohabitation, when the presence of a partner becomes a prerequisite for the existence of each of them. An example is the cohabitation of nodule bacteria and leguminous plants, which can live together on soils poor in nitrogen and enrich the soil with it.
The closest form of mutualism is when one organism lives inside another. A striking example of this is provided by the digestive system of cows and other ruminants. Cows, like humans, are unable to digest cellulose, a substance found in large quantities in plants. But ruminants have a special organ - a scar. It is a cavity in which many microbes live. Plant food, after the animal has chewed it, enters the rumen, and there these microbes destroy cellulose. (An animal can burp and re-chew partially digested food, which is exactly what cows do when they chew their cud.) A cow's rumen is a closed micro-ecosystem formed by many different microorganisms whose job it is to digest cellulose for their host. Similarly, the root system higher plants formed by the interweaving of root tissue and fungal filaments, so that the fungi supply the plant with minerals.
In the animal kingdom, termites provide an example of the most perfect symbiosis, the digestive tract of which serves as a haven for flagella or bacteria. Thanks to the symbiosis, the termites are able to digest the wood, and the micro-organisms have a shelter outside of which they cannot exist.
Mutually beneficial relationships can be formed on the basis of behavioral responses, for example, as in birds that combine their own food with the distribution of seeds. Sometimes species - mutualists enter into close physical interaction, as in the formation of mycorrhiza (fungal root) between fungi and plants.
For a long time it was not clear whether lichens should be classified as fungi or algae. It turned out that the lichen is a symbiotic system of fungus and algae, the functional and morphological relationship of which is so close that they can be considered as a special kind of organism, not similar to any of its constituent components. Therefore, lichens are usually classified not as symbioses of two species, but as certain types living organisms. The alga supplies the fungus with the products of photosynthesis, and the fungus, being a decomposer, supplies minerals for the alga and, in addition, is the substrate on which it lives. This allows lichens to exist in extremely harsh conditions.
Clownfish lives near sea anemones. In the event of a threat, the fish takes refuge in the tentacles of anemones. At the same time, clown fish drive away other fish that love to eat anemones. Thus, both organisms mutually benefit from this neighborhood. A variation of this type of mutualism is when one species feeds another: for example, a person grows agricultural plants and cattle; ants grow mushrooms.
Commensalism
Commensalism (lat. con mensa - literally “at the table”, “at the same table”) is the relationship between individuals or groups of different species that coexist without conflict and without mutual assistance (for example, common silverfish and humans).
The intestines of any animal contain a large number of different organisms. Some of the intestinal bacteria previously classified as commensals may be useful to the host, for example, by synthesizing B vitamins, some of which can be absorbed by the host. Therefore, such bacteria should be considered as symbionts rather than commensals. The opposite situations are also known, when organisms that were considered symbionts actually turned out to be commensals. It was assumed, in particular, that some ciliates (Entodinium, Epidinium, Diplodinium), found in huge quantities in the rumen and other parts of the ruminant stomach, help the host break down fiber and vegetable proteins, mix digested food, and control the number of bacteria and fungi. However, later it was shown that the digestion of these substances in ruminants (cattle, sheep, antelopes) is provided by other microorganisms.
Ectocommensalism is extremely widespread. An example of it can be the habitation of bacteria on the surface of human skin or some protozoa (ciliates Hypotricha, Chontricha, Peritricha, and representatives of the class of sucking ciliates Suctoria) on the surface of the body of many invertebrates (hydra, various sponges, crustaceans and annelids), as well as vertebrates ( fish, amphibians). The host is used by these species only as a habitat; he gets no benefit from them.
Some bacteria exhibit another form of commensalism. Thus, if one species of bacteria cannot use some potentially nutritious material, and another species of bacteria breaks down this material, forming substances that the first is able to consume, then the first species will grow as a commensal of the second. In this case, commensalism is represented in its literally- as "companionship" (lat. com - together, mensa - table, meal).
In general, the partners do not have any common interests, and each perfectly exists on its own. However, such alliances make it easier for one of the participants to move or get food, seek shelter, etc. Sometimes such alliances can be completely fictitious. So, in the shells of mollusks and shells of crustaceans, various types of bryozoans are sometimes found. This union is completely accidental, since bryozoans are able to attach themselves to any hard surface, and yet many sedentary animals benefit from attaching to a living creature. The owner carries them from place to place. Often, when moving, the flow of water makes it easier for them to get food.
Among the commensals, foleoxenes are distinguished, which are found in burrows and nests by chance; foleophiles, who are more common in these shelters than in the environment, and foleobists, who spend their whole lives in them.
Depending on the nature of the relationship of commensal species, three forms are distinguished:
Sinoikia (lodging) - one animal (commensal) uses another animal (its shell, nest, etc.) as a shelter;
epoykia (freeloading) - one animal (commensal) is attached to an animal of another species or lives near it, which becomes the "owner" (for example, a fish stuck with a sucker fin attaches to the skin of sharks and other large fish, moving with their help and eating the remains their meals;
entoikia - some animals settle inside the cavities of others that have communication with the external environment.
Freeloading is the consumption of the host's leftover food. Such, for example, are the relationships between lions and hyenas, picking up the remains of half-eaten food, or sharks with sticky fish.
Housing (cohabitation) - the use by some species of others (their bodies or their dwellings) as a shelter or dwelling. This type of relationship is widespread in plants.
An illustrative example of cohabitation is provided by some barnacles attached to the skin of a whale. They get the advantage of more fast travel, and the whale does not cause almost any inconvenience.
Commensalism is especially common among marine animals. The relationship that connects some fish with sharks is well known. Pilot fish, feeding on leftovers from the "table" of the shark, constantly scurry about in small shoals at its nose. Another example are animals whose burrow serves as a refuge for various "guests" who feed on scraps from the owner's table. In the burrows of mammals, nests of birds and dwellings of social insects, commensal insects are represented a large number species (for example, in the burrows of the alpine marmot up to 110 species of beetles).
Relations such as commensalism play an important role in nature, as they contribute to a closer cohabitation of species, a more complete development of the environment and the use of food resources.
All constituent parts of an animal and flora are closely related to each other and enter into complex relationships. Some are beneficial to the participants or generally vital, such as lichens (the result of a symbiosis of fungus and algae), others are indifferent, and still others are harmful. Based on this, it is customary to distinguish three types of relationships between organisms - this is neutralism, antibiosis and symbiosis. The first, in fact, is nothing special. These are such relations between populations living in the same territory, in which they do not influence each other, do not interact. But antibiosis and symbiosis - examples of which are very common, are important components of natural selection and participate in the divergence of species. Let's dwell on them in more detail.
Symbiosis: what is it?
It is a fairly common form of mutually beneficial cohabitation of organisms, in which the existence of one partner is impossible without the other. Most famous case- This is a symbiosis of a fungus and algae (lichens). Moreover, the first receives the products of photosynthesis synthesized by the second. And the algae extracts mineral salts and water from the hyphae of the fungus. Life alone is not possible.
Commensalism
Commensalism is actually a one-sided use by one species of another, without having a harmful effect on it. It can be carried out in several forms, but the main two are:
All others are to some extent modifications of these two forms. For example, entoykia, in which one species lives in the body of another. This is observed in karapus fish, which use the cloaca of holothurians (a species of echinoderms) as a dwelling, but feed outside it on various small crustaceans. Or epibiosis (some species live on the surface of others). In particular, barnacles feel good on humpback whales, absolutely not disturbing them.
Cooperation: description and examples
Cooperation is a form of relationship in which organisms can live separately, but sometimes come together for a common benefit. It turns out that this is an optional symbiosis. Examples:
Mutual cooperation and living together in an animal environment is not uncommon. Here are just a few of the more interesting examples.
Symbiotic relationships between plants
Plant symbiosis is very common, and if you look closely at the world around us, you can see it with the naked eye.
Symbiosis (examples) of animals and plants
The examples are very numerous, and many relationships between different elements of the plant and animal world are still poorly understood.
What is antibiosis?
Symbiosis, examples of which are found at almost every step, including in human life, as part of natural selection is important component evolution in general.
What is symbiosis in biology: definition
Symbiosis is any association between two different kinds of populations. Its study is the quintessence of systems biology, which integrates not only all levels of biological analysis, from molecular to ecological, but also studies the relationships between organisms in the three domains of life. The development of this area is still at its early stage, but in the near future the results will not be long in coming.
Types of symbiosis
What is symbiosis in biology (grade 5)? Symbiosis is a relationship between two or more organisms living in close contact with each other. An interaction occurs when two species live in the same place and one or both benefit from the other. Predation indirectly falls under this definition, since it can also be considered as a kind of symbiosis.
Mutualism
Mutualism is one of the best known and most ecologically significant types of symbiosis. Such relationships are, for example, insects and plants (pollination). Such cooperation is favorable and mutually beneficial for both parties. Insects, birds and even some mammals get their food in the form of nectar. The plant, on the other hand, gains a great reproductive advantage in that they are able to transfer their pollen to other plants.
Since plants do not often end up together, it is rather problematic for them to perform a reproductive function without intermediaries. AT this case symbiosis is simply vital for them, and in the full sense of the word. Without pollinators, many plants could simply fade away. On the other hand, without pollinating plants, many insects themselves would be in big trouble. This is truly a mutually beneficial alliance.
Examples of symbiosis in biology are not limited to this. Another fascinating variant of beneficial cooperation can be seen in the relationship of certain species of ants and aphids. Aphids are tiny, soft insects that feed on plant sap and excrete a certain amount of sugar and water as waste. This becomes suitable food for some species of ants. In turn, the ants often carry them to a new place, thus providing additional food sources.
Commensalism
What is symbiosis in biology? First of all, this is cooperation. One of the rarest types of symbiosis found in nature is commensalism. In this case, only one side benefits. The second from such an agreement is neither hot nor cold. Finding examples of it is quite a difficult task. However, several examples can be given.
An example of commensalism can be demonstrated by some desert lizards that find their place of residence in abandoned rat or snake holes. The lizards receive shelter while the other animal receives nothing in return.
What is symbiosis in biology? In simple words we can say that this is a positive, negative or neutral cooperation between different types of organisms.
