Includes biocenosis. Biocenosis as a biological system, types of biocenoses

A biocenosis is a collection of plants, animals, fungi and microorganisms that jointly inhabit an area of ​​the earth’s surface and are characterized by certain relationships both with each other and with a set of abiotic factors. The components of a biocenosis are phytocenosis (a set of plants), zoocenosis (a set of animals), mycocenosis (a set of fungi) and microcoenosis (a set of microorganisms). A synonym for biocenosis is community.

An area of ​​the earth's surface (land or body of water) with the same type of abiotic conditions (topography, climate, soils, moisture patterns, etc.), occupied by one or another biocenosis, is called a biotope (from the Greek topos - place). In spatial terms, the biotope corresponds to the biocenosis. The biotope, with which the organisms living here and the conditions of their existence are associated, is subject to changes from the biocenosis. The homogeneity of the climatic conditions of the biocenosis is determined by the climatope, the soil and ground conditions by the edaphotope, and the moisture content by the hydrotope.

In relation to terrestrial animals, the term “station” is more often used as a synonym for the term “habitat” - a section of space with a set of conditions necessary for the habitat of an animal species, for example, a squirrel station, a brown hare station, etc.

The territorial collection of biotopes forms larger units. Relatively homogeneous biotopes are combined into biochores. Thus, the biotopes of sandy, clayey, rocky, pebble and other deserts constitute the biochore of deserts, the biotopes of coniferous and deciduous forests constitute the biochore of temperate forests. Biochora in its content is close to the natural zone identified by geographers. Biochores are united into vital areas: land, sea and inland waters - the largest divisions of the biosphere with a set of abiotic factors unique to them. Biotope and biocenosis are components of an ecosystem - a natural complex formed by living organisms (biocenosis) and their habitat (biotope), which are interconnected by metabolism and energy. An ecosystem does not have strict taxonomic definition, and it can be objects of varying complexity and size - from a hummock to a continent, from a small body of water to the World Ocean. At the same time, the ecosystem is the main functional and structural natural system of the biosphere, since it consists of interdependent organisms and the abiotic environment that support life in the form in which it exists on Earth.

During field studies, the boundaries of a biocenosis are established according to a phytocenosis that has easily recognizable features. For example, a meadow community can be easily distinguished from a forest community, spruce forests from pine forests, a raised bog from a lowland one. Phytocenosis is the ecological framework of a biocenosis, determining its species composition and structure. Representing the leading structural component of the biocenosis, phytocenosis determines the species composition of the zoocenosis and microbiocenosis. They can perform their functions of improving the health of the changed environment only under the protection of the phytocenosis. Therefore, without creating an ecological framework, there can be no talk of protecting and rationally using land resources in agricultural areas. Wind erosion, contamination of groundwater with pesticides and nitrates, and reduction in animal populations to the point of complete extinction can be significantly reduced with this framework in place.

Species composition of the biocenosis

Each biocenosis is a system that includes many ecologically and biologically different species that arose as a result of selection and are capable of existing together in specific natural conditions. This system has its own species composition and structure; it is characterized by daily, seasonal and long-term dynamics, and the relationships of organisms both with each other and with the biotope.

The species composition of a biocenosis is a systematic set of species of plants, animals, fungi and microorganisms characteristic of a given biocenosis. The species composition of a phytocenosis is more or less constant compared to a zoocenosis, since animals move. Accounting for fungi and microorganisms is difficult due to excessive species abundance or their microscopic size. The greatest species diversity is found in the biocenoses of tropical rainforests, and the lowest in polar ice deserts.

The number of species of a biocenosis per unit area is called its species saturation. Different systematic groups of organisms in the same biocenosis differ sharply in species richness. Among terrestrial biocenoses, flowering plants are rich in this regard, the species richness of mushrooms and insects is somewhat less, and birds, mammals and other representatives of fauna are even less abundant. In the tundra, mosses and lichens have the greatest species diversity. The larger the territory the biocenosis occupies and the more favorable the environmental conditions, the greater the species composition. With a large species composition, we are talking about floristic and faunal richness.

The species that predominate in the biocenosis are called dominants. There are permanent and temporary dominants. The latter dominate only during a short growing season, being replaced by other, also temporary dominants. These include spring ephemeral plants: noble liverwort, oak wood anemone in European temperate forests and tulips in the southern steppes.

In a multi-tiered forest phytocenosis, dominants are present in all tiers. For example, in a pine-juniper-blueberry forest these are pine (tree layer), juniper (shrub layer) and blueberry (living ground cover). Moreover, the dominants of the upper tier have greater ecological significance than the lower ones. The tier may contain another species that is important, but less important than the dominant - the subdominant. Thus, in a birch-blueberry pine forest, the subdominant is birch if it forms a tree layer together with pine. Secondary species (assectators) are included in various tiers. In the biocenosis one can also find anthropophyte plants that have penetrated into the phytocenosis as a result of their deliberate or accidental introduction by humans.

It should be noted that dominance is not always associated with abundance and is a relative concept, especially in the animal world. A dominant is a species that predominates over others, although in a biocenosis it may have low numbers, for example in a desert with extremely sparse grass cover.

The dominants that determine the nature and structure of the biocenosis are called edificators (builders). Basically, these are those plants that create the internal biotic environment of the community: in a pine forest - pine, oak grove - oak, feather grass steppe - feather grass, etc. Subedificators are, as a rule, subdominants.

Biocenosis structure

The biocenosis is characterized by a vertical and horizontal structure. The vertical structure of the biocenosis is reflected in tiers - the vertical division of the community of organisms into fairly clearly limited horizons of activity. To a first approximation, layering is related to the habitat of organisms. Thus, we can distinguish species that live in the air, hydrosphere, lithosphere, soil environment and at the boundary of environments. In this case, tiering is a manifestation of the vertical division of the biosphere into its structural spheres.

The vertical structure of the biocenosis is largely determined by the tiers of the phytocenosis - the set of horizons of concentration of the most active plant organs (photosynthetic leaves and root systems). There are above-ground and underground tiers. Aboveground layering is the result of the selection of species capable of growing together, using horizons of the aboveground environment with different light intensities. It is clearly expressed in temperate forests, which, as a rule, have tree and shrub layers and living ground (grass-shrub or lichen, moss) cover. This vertical structure of the forest phytocenosis ensures a more complete use of the radiant energy of the Sun and above-ground space by plants. In addition, the forest is characterized by extra-storey vegetation (lianas, common in tropical rainforests, and various epiphytes).

The underground layering of the biocenosis reflects the vertical distribution of the root systems of plants in the phytocenosis. Thus, in the steppes there are three underground tiers: the upper one with the roots of annual plants, tubers and bulbs, the middle one with the roots of cereals (feather grass, fescue, etc.) and the deep one with tap root systems of plants. The presence of underground layers of phytocenosis ensures the most productive use of soil moisture: plants of different hygroecological groups grow in the same habitat - from xerophytes to hygrophytes.

The layering of the phytocenosis is of great ecological importance. It is the result of a long and complex process of interspecific competition and mutual adaptation of plants to each other. Thanks to it, the phytocenosis is formed by species that are very different in their ecology and have different life forms (tree, shrub, grass, moss, etc.).

Plants in an aquatic environment, such as freshwater bodies of water, are characterized by a corresponding layering pattern, which reflects their adaptability specifically to a given environment with its own light and temperature regime.

Animals change their tier position throughout the day, year, and life, spending a longer time in one tier or another than in others. Its various invertebrate inhabitants are associated with certain depths of the soil, but they are not strictly confined to the underground layers.

The horizontal structure of the biocenosis is reflected in synusias (from the Greek synusia - living together, community) - spatially and ecologically separated parts of the phytocenosis, consisting of plant species of one or more ecologically similar life forms.

Synusia can be layered, epiphytic (mosses, lichens and algae on tree trunks), intrasoil (microorganisms), etc.; permanent and temporary depending on the rhythms of development. They also differ in the number of individuals belonging to the same life form (reed synusia in reed thickets, lingonberries or blueberries in a pine forest), ecologically equivalent (pine and spruce synusia in a coniferous forest) or unequal (tree layer of a mixed forest, grass cover) life forms.

If stage is a morphological concept, then synusia is an ecological concept. It may coincide with the tier and may only form part of it. The dismemberment of the tree layer at the synusia can be observed if you rise high above the forest in autumn: dark coniferous spruce and light coniferous pines are replaced by yellowed birches, reddish aspens and brown oaks. In addition, the synusias reflect a mosaic of environmental factors in the formation of the plant community: pine occupied dry sandy soils, spruce occupied wetter sandy loam and loamy soils, birch and aspen occupied clearings, and oak occupied the most fertile soils.

Inhabiting a relatively homogeneous living space (a certain area of ​​land or water area), and interconnected by their environment. Biocenoses arose on the basis of the biogenic cycle and ensure it in specific natural conditions. Biocenosis is a dynamic system capable of self-regulation, the components of which (producers, consumers, decomposers) are interconnected. One of the main objects of ecology research.

The most important quantitative indicators of biocenoses are biodiversity (the total number of species in it) and biomass (the total mass of all types of living organisms in a given biocenosis).

Types of biocenosis structures: species, spatial (vertical (tiered) and horizontal (mosaic) organization of the biocenosis) and trophic.

Biotopes are characterized by a certain species manifold- the totality of populations included in its composition. The number of species depends on the duration of existence, climate stability, and productivity of the type of biocenosis (desert, tropical forest).

The number of individuals of different species varies, etc. The most numerous types of biotopes are called dominant. When studying large biotopes, it is impossible to determine all species diversity. For study, the number of species from a certain territory (area) is determined - species richness. The species diversity of different biocenoses is compared by species richness from the same area.

The species structure gives an idea of ​​the qualitative composition of the biocenosis. When two species exist together in a homogeneous environment under constant conditions, one of them is completely replaced by the other. Competitive relationships arise. Based on such observations, it was formulated principle of competitive exclusion, or Gause's principle.

Spatial structure

The spatial structure of the biocenosis can be characterized by vertical tiers. Vertical layering in plants is determined by how high above the ground a particular plant carries its photosynthetic parts (shade-tolerant plant or light-loving plant):

• Tree layer
• Shrub layer
• Shrub-herbaceous layer
• Moss-lichen layer

Vertical layering in animals can be considered using the example of insects (layering of birds is also possible, for example, the same species of bird can live on different tiers of the same plant):

• Geobia (soil inhabitants)
• Herpetobia (inhabitants of the surface layer)
• Bryobia (moss dwellers)
• Phyllobia (grass dwellers)
• Aerobians (inhabitants of higher tiers)

Horizontal structuring of a community (mosaic, heterogeneous) can be caused by a number of factors:

• Abiogenic mosaic (factors (plant organisms, in particular - edificators - lichens)
• Aeolian-phytogenic (mosaicity caused by both abiotic and phytogenic factors)
• Biogenic (mosaicity caused primarily by burrowing animals)

Ecological structure

It is characterized by the ratio of species that have different adaptations to environmental factors, types of nutrition, size, and appearance. Biocenosis is the ratio of species occupying certain ecological niches.

Types of biocenoses:

1. Natural (river, lake, meadow, etc.)
2. Artificial (pond, garden, etc.)

Characteristics of biocenosis indicators

1. The sizes of biocenoses are different - from small (a hummock in a swamp, a pond) to very large (biocenosis of a forest, meadow, feather grass steppe).
2. The size of the biocenosis is determined by the conditions of the abiotic environment. The homogeneous space (part of the abiotic environment) occupied by a biocenosis is called biotope.
3. Biocenoses do not have clear boundaries; they gradually transform into each other. The transition strip between adjacent communities is called an ecton.

Compound

see also

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Notes

Literature

• Shilov I. A. Ecology. - M.: Higher School, 1997. - P. 373-389.

An excerpt characterizing Biocenosis

On the square where the sovereign went, a battalion of Preobrazhensky soldiers stood face to face on the right, and a battalion of the French Guard in bearskin hats on the left.
While the sovereign was approaching one flank of the battalions, which were on guard duty, another crowd of horsemen jumped up to the opposite flank and ahead of them Rostov recognized Napoleon. It couldn't be anyone else. He rode at a gallop in a small hat, with a St. Andrew's ribbon over his shoulder, in a blue uniform open over a white camisole, on an unusually thoroughbred Arabian gray horse, on a crimson, gold embroidered saddle cloth. Having approached Alexander, he raised his hat and with this movement, Rostov’s cavalry eye could not help but notice that Napoleon was sitting poorly and not firmly on his horse. The battalions shouted: Hurray and Vive l "Empereur! [Long live the Emperor!] Napoleon said something to Alexander. Both emperors got off their horses and took each other's hands. There was an unpleasantly feigned smile on Napoleon's face. Alexander said something to him with an affectionate expression .
Rostov, without taking his eyes off, despite the trampling of the horses of the French gendarmes besieging the crowd, followed every move of Emperor Alexander and Bonaparte. He was struck as a surprise by the fact that Alexander behaved as an equal with Bonaparte, and that Bonaparte was completely free, as if this closeness with the sovereign was natural and familiar to him, as an equal, he treated the Russian Tsar.
Alexander and Napoleon with a long tail of their retinue approached the right flank of the Preobrazhensky battalion, directly towards the crowd that stood there. The crowd suddenly found itself so close to the emperors that Rostov, who was standing in the front rows, became afraid that they would recognize him.
“Sire, je vous demande la permission de donner la legion d"honneur au plus brave de vos soldats, [Sire, I ask your permission to give the Order of the Legion of Honor to the bravest of your soldiers,] said a sharp, precise voice, finishing each letter It was the short Bonaparte who spoke, looking straight into Alexander's eyes from below. Alexander listened attentively to what was being said to him, and bowed his head, smiling pleasantly.
“A celui qui s"est le plus vaillament conduit dans cette derieniere guerre, [To the one who showed himself bravest during the war],” Napoleon added, emphasizing each syllable, with a calm and confidence outrageous for Rostov, looking around the ranks of Russians stretched out in front of there are soldiers, keeping everything on guard and motionlessly looking into the face of their emperor.
“Votre majeste me permettra t elle de demander l"avis du colonel? [Your Majesty will allow me to ask the colonel’s opinion?] - said Alexander and took several hasty steps towards Prince Kozlovsky, the battalion commander. Meanwhile, Bonaparte began to take off his white glove, small hand and, tearing it apart, threw it in. The adjutant, hastily rushing forward from behind, picked it up.
- Who should I give it to? – Emperor Alexander asked Kozlovsky not loudly, in Russian.
- Whom do you order, Your Majesty? “The Emperor winced with displeasure and, looking around, said:
- But you have to answer him.
Kozlovsky looked back at the ranks with a decisive look and in this glance captured Rostov as well.
“Isn’t it me?” thought Rostov.
- Lazarev! – the colonel commanded with a frown; and the first-ranked soldier, Lazarev, smartly stepped forward.
-Where are you going? Stop here! - voices whispered to Lazarev, who did not know where to go. Lazarev stopped, looked sideways at the colonel in fear, and his face trembled, as happens with soldiers called to the front.
Napoleon slightly turned his head back and pulled back his small chubby hand, as if wanting to take something. The faces of his retinue, having guessed at that very second what was going on, began to fuss, whisper, passing something on to one another, and the page, the same one whom Rostov saw yesterday at Boris’s, ran forward and respectfully bent over the outstretched hand and did not make her wait either one second, he put an order on a red ribbon into it. Napoleon, without looking, clenched two fingers. The Order found itself between them. Napoleon approached Lazarev, who, rolling his eyes, stubbornly continued to look only at his sovereign, and looked back at Emperor Alexander, thereby showing that what he was doing now, he was doing for his ally. A small white hand with an order touched the button of soldier Lazarev. It was as if Napoleon knew that in order for this soldier to be happy, rewarded and distinguished from everyone else in the world forever, it was only necessary for him, Napoleon’s hand, to be worthy of touching the soldier’s chest. Napoleon just put the cross to Lazarev's chest and, letting go of his hand, turned to Alexander, as if he knew that the cross should stick to Lazarev's chest. The cross really stuck.

STRUCTURE OF BIOCENOSIS

What are biocenoses

Groups of co-living and mutually related organisms are calledbiocenoses. The adaptability of members of a biocenosis to living together is expressed in a certain similarity of requirements for the most important abiotic environmental conditions and natural relationships with each other.

The term “biocenosis” is more often used in relation to the population of territorial areas that are distinguished on land by relatively homogeneous vegetation (usually along the boundaries of plant associations), for example, the biocenosis of spruce-sorrel forest, the biocenosis of upland meadow, white moss pine forest, the biocenosis of feather grass steppe, wheat field, etc. ). This refers to the entire set of living beings - plants, animals, microorganisms, adapted to living together in a given territory. In the aquatic environment, biocenoses are distinguished that correspond to the ecological divisions of parts of reservoirs, for example, biocenoses of coastal pebble, sandy or silty soils, and abyssal depths.

STRUCTURE OF BIOCENOSIS

1.Species structure of the biocenosis.

Under species structure biocenosis understand the diversity of species in it and the ratio of their numbers or mass. There are species-poor and species-rich biocenoses. In polar arctic deserts and northern tundras with extreme heat deficiency, in waterless hot deserts, in reservoirs heavily polluted by sewage, wherever one or several environmental factors deviate far from the average optimal level for life, communities are greatly impoverished, since only few species can adapt to such extreme conditions. Wherever abiotic conditions approach the average optimum for life, extremely species-rich communities emerge. Examples of these include tropical forests, coral reefs with their diverse populations, river valleys in arid dry regions, etc.

The species composition of biocenoses, in addition, depends on the duration of their existence. Young, just emerging communities usually include a smaller set of species than long-established, mature ones. Biocenoses created by humans (fields, vegetable gardens, orchards) are also poorer in species than similar natural systems (forest, steppe, meadow. However, even the most impoverished biocenoses include at least several dozen species of organisms belonging to different systematic and ecological groups.

In some conditions, biocenoses are formed in which there are no plants (for example, in caves or reservoirs below the photic zone), and in exceptional cases, consisting only of microorganisms (in an anaerobic environment, at the bottom of a reservoir, in rotting sludge). Species-rich natural communities include thousands and even tens of thousands of species, united by a complex system of relationships.

The influence of a variety of conditions on the diversity of species is manifested, for example, in the so-called "borderline", or edge , effect. It is well known that on the edges the vegetation is usually lush and richer, more species of birds nest, more species of insects, spiders, etc. are found than in the depths of the forest. The conditions of illumination, humidity, and temperature are more varied here. The stronger the differences between two neighboring biotypes, the more heterogeneous the conditions at their boundaries and the stronger the border effect. Species richness increases greatly in places of contact between forest herbaceous, aquatic and land communities, etc.

The species that predominate in numbers are dominants communities. For example, in our spruce forests, spruce dominates among the trees, wood sorrel and other species dominate in the grass cover, wood oxalis and other species dominate in the bird population, kinglets, robin, and chiffchaffs dominate among the mouse-like rodents, bank voles and red-gray voles, etc. However, not all dominant species equally influence the biocenosis. Among them, those stand out that, through their vital activity, to the greatest extent create the environment for the entire community and without which, therefore, the existence of most other species is impossible. Such species are called edifiers. The main edificators of terrestrial biocenoses are certain types of plants: in spruce forests - spruce, in pine forests - pine, in the steppes - turf grasses (feather grass, fescue, etc.). In some cases, animals can also be edificators. For example, in territories occupied by marmot colonies, it is their digging activity that mainly determines the nature of the landscape, microclimate, and plant growth conditions.

In addition to a relatively small number of dominant species, biocenoses include many small and rare forms. They create its species richness, increase the diversity of biocenotic connections and serve as a reserve for the replenishment and replacement of dominants, i.e. give the biocenosis stability and ensure the reliability of its functioning in different conditions. The greater the reserve of such minor species in a community, the greater the likelihood that among them there will be those that can play the role of dominants in the event of any changes in the environment.

The more specific the environmental conditions, the poorer the species composition of the community and the higher the number of individual species. In the richest biocenoses, almost all species are small in number.

The diversity of a biocenosis is closely related to its stability: the higher the species diversity, the more stable the biocenosis . Human activity greatly reduces diversity in natural communities.

2. Spatial structure .

The spatial structure of the biocenosis is determined first
in total, the composition of its plant part - phytocenosis, the distribution of above-ground and underground plant masses. Phytocenosis often acquires a clear longline addition : The assimilating above-ground plant organs and their underground parts are arranged in several layers, using and changing the environment in different ways. Layering is especially noticeable in temperate forests. For example, in spruce forests the tree, herb-shrub and moss layers are clearly distinguished. 5-6 tiers can be distinguished in a broad-leaved forest: the first, or upper, tier is formed by trees of the first size (pedunculate oak, cordate linden, sycamore maple, smooth elm, etc.); the second - trees of the second size (common mountain ash, wild apple and pear trees, bird cherry, goat willow, etc.); the third tier is the undergrowth formed by shrubs (common hazel, brittle buckthorn, forest honeysuckle, European euonymus, etc.); the fourth consists of tall grasses (borets, spreading boron, forest chist, etc.); the fifth tier is made up of lower herbs (common sedge, hairy sedge, perennial grass, etc.); in the sixth tier - the lowest grasses, such as European hoofed grass.

In forests there are always inter-tiered (extra-tiered) plants - these are algae and lichens on the trunks and branches of trees, higher spore and flowering epiphytes, lianas, etc. Layering allows plants to more fully use the light flux: shade-tolerant, even shade-loving, plants can exist under the canopy of tall plants , intercepting even weak sunlight. Vegetation layers can be of different lengths: the tree layer, for example, is several meters thick, and the grass cover is only a few centimeters thick. Each tier participates in the creation of phytoclimate in its own way and is adapted to a certain set of conditions.

The underground layering of phytocenoses is associated with different rooting depths of the plants included in their composition, with the placement of the active part of the root systems. In forests you can often observe several (up to six) underground tiers.

Animals are also predominantly confined to one or another layer of vegetation. Some of them do not leave the corresponding tier at all. For example, among insects the following groups are distinguished: soil inhabitants - geobius , ground, surface layer - herpetobium , , moss layer - bryobium, grass stand - phyllobium, higher tiers - aerobium.

Dismemberment in the horizontal direction is mosaic. Mosaic due to a number of reasons: heterogeneity of microrelief, soils, environment-forming influence of plants and their environmental features. It can arise as a result of animal activity (formation of soil emissions and their subsequent overgrowing, formation of anthills, trampling and eating of grass by ungulates, etc.) or humans (selective felling, fire pits, etc.), due to tree fallouts during hurricanes, etc. Changes in the environment under the influence of the vital activity of individual plant species create the so-called phytogenic mosaic.

3. Ecological structure of the biocenosis.

Different types of biocenoses are characterized by a certain ratio of ecological groups of organisms, which expresses the ecological stricture of the community. Biocenoses with similar ecological structures may have different species composition, since in them the same ecological niches can be occupied by species that are similar in ecology, but are far from related. Such types that perform the same , functions in similar biocenoses are called vicarious. For example, bison in the prairies of North America, antelopes in the savannas of Africa, wild horses and kulans in the steppes of Asia share the same ecological niche. The ecological structure of biocenoses that develop in certain climatic and landscape conditions is strictly natural. For example, in biocenoses of different natural zones the ratio of phytophages and saprophages naturally changes. In steppe, semi-desert and desert areas, animal phytophages predominate over saprophages; in forest communities of the temperate zone, on the contrary, saprophagy is more developed. The main type of feeding of animals in the depths of the ocean is predation , whereas in the illuminated, surface zone of the pelagic there are many filter feeders that consume phytoplankton or species with a mixed feeding pattern.

The ecological structure of communities is also reflected by the ratio of such groups of organisms as hygrophytes, mesophytes and xerophytes among plants or hygrophiles, mesophylls and xerophytes among animals. It is quite natural that in dry arid conditions the vegetation is characterized by a predominance of sclerophytes and succulents, while in highly moist biotopes hygro- and even hydrophytes are more abundant.

The relationship of organisms in the biocenosisX.

The basis for the emergence and existence of biocenoses is the relationship of organisms, their connections into which they enter into each other, inhabiting the same biotope. These connections determine the basic living conditions of species in a community, the possibilities of obtaining food and conquering new space.

1.Trophic connections occur when one species feeds on another ­ gim-either living individuals, or their dead remains, or waste products. Dragonflies that catch other insects in flight, dung beetles that feed on the droppings of large ungulates, and bees that collect plant nectar enter into a direct trophic relationship with species that provide food. In the case of competition between two species over food objects, an indirect trophic relationship arises between them, since the activity of one affects the food supply of the other. Any effect of one species on the eatability of another or the availability of food for it should be regarded as an indirect trophic relationship between them. For example, caterpillars of nun butterflies, eating pine needles, make it easier for bark beetles to gain access to weakened trees.

Topical and trophic connections are of greatest importance in a biocenosis and form the basis of its existence. It is these types of relationships that keep organisms of different species close to each other, uniting them into fairly stable communities of different scales.

3. Phoric connections. This is the participation of one species in the spread of another. Animals act as transporters. The transfer of seeds, spores, and plant pollen by animals is called zoochory; the transfer of other smaller animals is called zoochory. phoresia. Animals can capture plant seeds in two ways: passive and active. Passive capture occurs when an animal's body accidentally comes into contact with a plant, the seeds or infructescences of which have special hooks, hooks, and outgrowths (straw, burdock). The active method of capture is eating fruits and berries. Animals excrete seeds that cannot be digested along with their droppings. Animal phoresia is common mainly among small arthropods, especially in various groups of mites. It is one of the methods of passive dispersal and is characteristic of species for which transfer from one biotope to another is vital for preservation or prosperity. Dung beetles sometimes crawl with raised elytra, which they are unable to fold due to mites densely littering their bodies. Among large animals, phoresia is almost never found.

4. Factory connections . This is a type of biocenotic relationship into which a species enters, using excretory products, either dead remains, or even living individuals of another species for its constructions (fabrication). So birds use tree branches, mammal fur, grass, leaves, down and feathers of other bird species, etc. to build nests. The megachila bee places eggs and supplies in cups constructed from the soft leaves of various shrubs (rose hips, lilac, acacia, etc.).

All living nature that surrounds us - animals, plants, mushrooms and other living organisms - is a whole biocenosis or part, for example, of a regional biocenosis or the biocenosis of a separate part. All biocenoses have different conditions and may differ in the types of organisms and plants.

In contact with

Biocenosis is community, a set of living organisms in the nature of a certain territorial area. The concept also implies environmental conditions. If a separate territory is taken, then within its boundaries there should be approximately the same climate. The biocenosis can extend to the inhabitants of land, water and.

All organisms in the biocenosis are closely related to each other. There are food connections, or with the habitat and distribution. Some populations use others to build their own shelters.

There is also a vertical and horizontal structure of the biocenosis.

Attention! The biocenosis can be natural or artificial, that is, man-made.

In the 19th century, biology was actively developing, like other branches of science. Scientists continued to describe living organisms. In order to simplify the task of describing groups of organisms that inhabit a specific territory, Karl August Moebius was the first to introduce the term “biocenosis”. This happened in 1877.

Signs of biocenosis

There are the following signs of biocenosis:

1. There is a close relationship between the populations.
2. The biotic connection between all components is stable.
3. Organisms adapt to each other and in groups.
4. A biological cycle is observed in this area.
5. Organisms interact with each other, so they are mutually necessary.

Components

The components of a biocenosis are all living organisms. They are divided into three large groups:

• consumers - consumers of finished substances (for example, predators);
• producers - can produce nutrients on their own (for example, green plants);
• decomposers are those organisms that are the final link in the food chain, that is, they decompose dead organisms (for example, fungi and bacteria).

Components of biocenosis

Abiotic part of the biocenosis

Abiotic environment- this is climate, weather, relief, landscape, etc., that is, this is the inanimate part. Conditions will differ on different parts of the continents. The harsher the conditions, the fewer species will be present in the area. The equatorial belt has the most favorable climate - warm and humid, so endemic species are most often found in such areas (many of them can be found on the Australian mainland).

A separate area of ​​the abiotic environment called a biotope.

Attention! The richness of species within the biocenosis depends on the conditions and nature of the abiotic environment.

Types of biocenosis

In biology, types of biocenosis are classified according to the following characteristics.

By spatial location:

• Vertical (tiered);
• Horizontal (mosaic).

By origin:

• Natural (natural);
• Artificial (man-made).

By connection type species within the biocenosis:

• Trophic (food chains);
• Factory (arrangement of habitats of an organism with the help of dead organisms);
• Topical (individuals of one species serve as habitats or influence the lives of other species);
• Phoric (participation of some species in the distribution of the habitat of others).

Spatial structure of the biocenosis

Natural biocenosis

Natural biocenosis is characterized by the fact that it has a natural origin. A person does not interfere with the processes occurring in it. For example: Volga River, forest, steppe, meadow, mountains. Unlike artificial ones, natural ones have a larger scale.

If a person interferes with the natural environment, the balance between species is disrupted. Irreversible processes are taking place - the extinction and disappearance of some species of plants and animals, they are indicated in "". Those species that are on the verge of extinction are listed in the Red Book.

Let's look at examples of natural biocenosis.

River

The river is natural biocenosis. It is home to various animals, plants and bacteria. The views will vary depending on the location of the river. If the river is located in the north, then the diversity of the living world will be poor, but if it is closer to the equator, then the abundance and diversity of species living there will be rich.

Inhabitants of river biocenoses: beluga, perch, crucian carp, pike, sterlet, herring, ide, bream, pike perch, ruffe, smelt, burbot, crayfish, asp, carp, carp, catfish, roach, track, silver carp, sabrefish, various freshwater algae and many other living organisms.

Forest

Forest is example of a natural look. The forest biocenosis is rich in trees, shrubs, grass, animals that live in the air, on the ground and in the soil. Here you can find mushrooms. Various bacteria also live in the forest.

Representatives of the forest biocenosis (fauna): wolf, fox, elk, wild boar, squirrel, hedgehog, hare, bear, elk, tit, woodpecker, chaffinch, cuckoo, oriole, black grouse, wood grouse, thrush, owl, ant, ladybug, pine silkworm, grasshopper, tick and many other animals.

Representatives of the forest biocenosis (plant world): birch, linden, maple, elderberry, corydalis, oak, pine, spruce, aspen, lily of the valley, kupir, strawberry, blackberry, dandelion, snowdrop, violet, forget-me-not, lungwort, hazel and many other plants.

The forest biocenosis is represented by the following mushrooms: boletus, boletus, porcini mushroom, toadstool, fly agaric, oyster mushroom, puffball, chanterelle, oiler, honey fungus, morel, russula, champignon, saffron milk cap, etc.

Natural and artificial biocenosis

Artificial biocenosis

An artificial biocenosis differs from a natural one in that it created by human hands to satisfy their needs or the needs of the whole society. In such systems, a person himself designs the required conditions. Examples of such systems are: garden, vegetable garden, field, forest plantation, apiary, aquarium, canal, pond, etc.

The emergence of artificial environments led to the destruction of natural biocenoses and the development of agriculture and the agricultural sector of the economy.

Examples of artificial classification

For example, in a field, greenhouse, garden or vegetable garden, a person grows cultivated plants (vegetables, grain crops, fruitful plants, etc.). So that they don't die, certain conditions are created: Irrigation systems for watering, lighting. The soil is saturated with the missing elements with the help of fertilizers. Plants are treated with chemicals to protect them from being eaten by pests, etc.

Forest belts are planted near fields, on the slopes of ravines, near railways and roads. Near the fields they are needed in order to reduce evaporation and retain snow in the spring, i.e. to control the water regime of the earth. Trees also protect seeds from being blown away by the wind and protect the soil from erosion.

Trees are planted on the slopes of ravines in order to prevent and slow down their growth, since the roots will hold the soil.

Trees along roads are necessary to prevent snow, dust, and sand from driving transport routes.

Attention! Man creates artificial biocenoses in order to improve the life of society. But excessive interference with nature is fraught with consequences.

Horizontal structure of biocenosis

The horizontal structure of a biocenosis differs from the tiered one in that the abundance of species living on its territory changes not vertically, but horizontally.

For example, we can consider the most global example. The diversity, abundance and richness of the living world varies by zone. In the zone of arctic deserts, in the arctic climate zone, the flora and fauna are sparse and poor. As we approach the tropical forest zone, in the tropical climate zone, the number and diversity of species will increase. So we were able to trace changes in the number of species within the biocenosis, and even changes in their structure (since they have to adapt to different climate conditions). This is a natural mosaic.

And artificial mosaic occurs under human influence on the environment. For example, deforestation, sowing meadows, draining swamps, etc. In a place where people have not changed the conditions, the organisms will remain. And those places where conditions have changed will be inhabited by new populations. The components of the biocenosis will also differ.

Biocenosis

The concept of biogeocenosis and ecosystem

Conclusion

Let's summarize: biocenosis has different classifications depending on its origin, relationships between organisms and location in space. They differ in territorial scale and the species that live within their boundaries. Signs of biocenosis can be classified separately for each area.

Biocenosis— a set of populations of plants, animals and microorganisms. The place occupied by a biocenosis is called a biotope. The species structure of a biocenosis covers all species living in it. The spatial structure includes a vertical structure - tiers and a horizontal structure - microcenoses and microassociations. The trophic structure of the biocenosis is represented by producers, consumers and decomposers. The transfer of energy from one species to another by eating them is called a food (trophic) chain. The place of an organism in the food chain, associated with its food specialization, is called the trophic level. The trophic structure of a biocenosis and ecosystem is usually displayed by graphic models in the form of ecological pyramids. There are ecological pyramids of numbers, biomass and energy. The rate of solar energy fixation determines the productivity of biocenoses. The set of environmental factors within which a species lives is called an ecological niche. The tendency to increase the diversity and density of living organisms at the boundaries of biocenoses (in ecotones) is called the edge effect.

The concept of biocenosis

Organisms do not live on Earth as independent individuals. They form regular complexes in nature. German hydrobiologist K. Möbius in the late 70s. XIX century studied complexes of bottom animals - clusters of oysters (oyster banks). He observed that, along with oysters, there were also animals such as starfish, echinoderms, bryozoans, worms, ascidians, sponges, etc. The scientist concluded that these animals live together in the same habitat, not by chance. They need the same conditions as oysters. Such groupings appear due to similar requirements for environmental factors. Complexes of living organisms that constantly meet together at different points of the same water basin under the same conditions of existence were called biocenoses by Mobius. The term “biocenosis” (from the Greek bios - life and koinos - general) was introduced by him into the scientific literature in 1877.

The merit of Möbius is that he not only established the existence of organic communities and proposed a name for them, but also managed to reveal many patterns of their formation and development. Thus, the foundations were laid for an important direction in ecology - biocenology (ecology of communities).

The biocenotic level is the second (after population) supra-organismal level of organization of living systems. A biocenosis is a fairly stable biological formation that has the ability to self-maintain its natural properties and species composition under external influences caused by changes in climatic and other factors. The stability of a biocenosis is determined not only by the stability of its constituent populations, but also by the characteristics of the interaction between them.

- these are historically established groups of plants, animals, fungi and microorganisms that inhabit a relatively homogeneous living space (a piece of land or a body of water).

So, each biocenosis consists of a certain set of living organisms belonging to different species. But it is known that individuals of the same species unite into natural systems called populations. Therefore, a biocenosis can also be defined as a set of populations of all types of living organisms inhabiting common habitats.

It should be noted that the term “biocenosis” has become widespread in the scientific literature in German and Russian, and in English-speaking countries it corresponds to the term “community”. However, strictly speaking, the term “community” is not synonymous with the term “biocenosis”. If a biocenosis can be called a multi-species community, then a population (an integral part of the biocenosis) is a single-species community.

The composition of a biocenosis includes a set of plants in a certain territory - phytocenosis(from Greek phyton - plant); the totality of animals living within the phytocenosis - zoocenosis(from Greek zoon - animal); microbiocenosis(from the Greek mikros - small + bios - life) - a set of microorganisms that inhabit the soil. Sometimes they include as a separate component element in the biocenosis mycocenosis(from Greek mykes - mushroom) - a collection of mushrooms. Examples of biocenoses are deciduous, spruce, pine or mixed forest, meadow, swamp, etc.

The homogeneous natural living space (part of the abiotic environment) occupied by a biocenosis is called biotope. This could be a piece of land or a body of water, a seashore or a mountainside. A biotope is an inorganic environment that is a necessary condition for the existence of a biocenosis. Biocenosis and biotope closely interact with each other.

The scale of biocenoses can be different - from communities of lichens on tree trunks, moss hummocks in a swamp or a decaying stump to the population of entire landscapes. Thus, on land, one can distinguish the biocenosis of a dry meadow (not flooded with water), the biocenosis of a white moss pine forest, the biocenosis of feather grass steppe, the biocenosis of a wheat field, etc.

A specific biocenosis includes not only organisms that permanently inhabit a certain territory, but also those that have a significant impact on it. For example, many insects breed in bodies of water, where they serve as an important source of food for fish and some other animals. At a young age, they are part of the aquatic biocenosis, and as adults they lead a terrestrial lifestyle, i.e. act as elements of land biocenoses. Hares can eat in the meadow and live in the forest. The same applies to many species of forest birds that look for food not only in the forest, but also in adjacent meadows or swamps.

Species structure of biocenosis

Species structure of biocenosis is the totality of its constituent species. In some biocenoses, animal species may predominate (for example, the biocenosis of a coral reef); in other biocenoses, plants play the main role: the biocenosis of a floodplain meadow, feather grass steppe, spruce, birch, and oak forest. The number of species (species diversity) in different biocenoses is different and depends on their geographical location. The most well-known pattern of changes in species diversity is its decrease from the tropics towards high latitudes. The closer to the equator, the richer and more diverse the flora and fauna. This applies to all forms of life, from algae and lichens to flowering plants, from insects to birds and mammals.

In the rain forests of the Amazon basin, on an area of ​​about 1 hectare, you can count up to 400 trees of more than 90 species. In addition, many trees serve as supports for other plants. Up to 80 species of epiphytic plants grow on the branches and trunk of each tree.

An example of species diversity is one of the volcanoes in the Philippines. There are more tree species growing on its slopes than in the entire United States!

Unlike the tropics, the biocenosis of a pine forest in the temperate zone of Europe can include a maximum of 8-10 tree species per 1 hectare, and in the north of the taiga region there are 2-5 species in the same area.

The poorest biocenoses in terms of the set of species are alpine and arctic deserts, the richest are tropical forests. Panama's rainforests are home to three times more species of mammals and birds than Alaska.

A simple indicator of the diversity of a biocenosis is the total number of species, or species richness. If any species of plant (or animal) quantitatively predominates in a community (has greater biomass, productivity, number or abundance), then this species is called dominant, or dominant species(from Latin dominans - dominant). There are dominant species in any biocenosis. For example, in a spruce forest, spruce trees, using the main share of solar energy, increase the greatest biomass, shade the soil, weaken air movement and create a lot of inconvenience for the lives of other forest inhabitants.

Spatial structure of the biocenosis

Species can be distributed differently in space according to their needs and habitat conditions. This distribution of species that make up the biocenosis in space is called spatial structure of the biocenosis. There are vertical and horizontal structures.

Vertical structure a biocenosis is formed by its individual elements, special layers called tiers. Tier - co-growing groups of plant species that differ in height and position in the biocenosis of assimilating organs (leaves, stems, underground organs - tubers, rhizomes, bulbs, etc.). As a rule, different tiers are formed by different life forms (trees, shrubs, shrubs, herbs, mosses). The layering is most clearly expressed in forest biocenoses (Fig. 1).

First, woody, tier usually consists of tall trees with high-mounted foliage that is well illuminated by the sun. Unused light can be absorbed by trees, forming a second, subcanopy, tier.

Understory layer are made up of shrubs and shrubby forms of tree species, for example hazel, rowan, buckthorn, willow, forest apple, etc. In open areas under normal environmental conditions, many shrubby forms of such species as mountain ash, apple, and pear would have the appearance of trees of the first size. However, under the forest canopy, in conditions of shading and lack of nutrients, they are doomed to exist in the form of low-growing, often non-barking seeds and fruits of trees. As the forest biocenosis develops, such species will never reach the first tier. This is how they differ from the next tier of the forest biocenosis.

Rice. 1. Tiers of forest biocenosis

TO adolescent layer These include young, low (from 1 to 5 m) trees, which in the future will be able to enter the first tier. These are the so-called forest-forming species - spruce, pine, oak, hornbeam, birch, aspen, ash, black alder, etc. These species can reach the first tier and form biocenoses with their dominance (forests).

Under the canopy of trees and shrubs there is herbaceous-shrub layer. This includes forest herbs and shrubs: lily of the valley, oxalis, strawberries, lingonberries, blueberries, ferns.

The ground layer of mosses and lichens forms moss-lichen layer.

So, in the forest biocenosis there are tree stand, undergrowth, undergrowth, grass cover and moss-lichen layer.

Similar to the distribution of vegetation by tiers, in biocenoses different species of animals also occupy certain levels. Soil worms, microorganisms, and digging animals live in the soil. Various centipedes, ground beetles, mites and other small animals live in leaf litter and on the soil surface. Birds nest in the upper canopy of the forest, and some can feed and nest below the upper tier, others in bushes, and still others near the ground. Large mammals live in the lower tiers.

Tiering is inherent in the biocenoses of oceans and seas. Different types of plankton stay at different depths depending on the lighting. Different species of fish live at different depths depending on where they find food.

Individuals of living organisms are distributed unevenly in space. Usually they form groups of organisms, which is an adaptive factor in their life. Such groupings of organisms determine horizontal structure of the biocenosis- horizontal distribution of individuals forming various kinds of patterning and spotting of each species.

There are many examples of such distribution: these are numerous herds of zebras, antelopes, elephants in the savanna, colonies of corals on the seabed, schools of sea fish, flocks of migratory birds; thickets of reeds and aquatic plants, accumulations of mosses and lichens on the soil in a forest biocenosis, patches of heather or lingonberries in the forest.

The elementary (structural) units of the horizontal structure of plant communities include microcenosis and microgrouping.

Microcenosis(from the Greek micros - small) - the smallest structural unit of the horizontal division of a community, which includes all tiers. Almost every community includes a complex of microcommunities or microcenoses.

Microgrouping - condensation of individuals of one or several species within a tier, intra-tier mosaic spots. For example, in the moss layer, various moss patches with dominance of one or several species can be distinguished. In the grass-shrub layer there are blueberry, blueberry-sour sorrel, and blueberry-sphagnum microgroups.

The presence of mosaics is important for the life of the community. Mosaicism allows for more complete use of different types of microhabitats. Individuals forming groups are characterized by high survival rates and use food resources most efficiently. This leads to an increase and diversity of species in the biocenosis, contributing to its stability and viability.

Trophic structure of biocenosis

The interaction of organisms occupying a certain place in the biological cycle is called trophic structure of the biocenosis.

In the biocenosis, three groups of organisms are distinguished.

1.Producers(from Latin producens - producing) - organisms that synthesize from inorganic substances (mainly water and carbon dioxide) all organic substances necessary for life, using solar energy (green plants, cyanobacteria and some other bacteria) or the energy of oxidation of inorganic substances (sulfur bacteria , iron bacteria, etc.). Typically, producers are understood as green chlorophyll-bearing plants (autotrophs) that provide primary production. The total weight of dry matter of phytomass (plant mass) is estimated at 2.42 x 10 12 tons. This constitutes 99% of all living matter on the earth's surface. And only 1% accounts for heterotrophic organisms. Therefore, planet Earth owes its existence to vegetation only to the existence of life on it. It was green plants that created the necessary conditions for the appearance and existence, first, of various prehistoric animals, and then of humans. When they died, the plants accumulated energy in coal deposits, peat and oil sludge.

Producing plants provide humans with food, raw materials for industry, and medicine. They purify the air, trap dust, soften the air temperature, and muffle noise. Thanks to vegetation, there is a huge variety of animal organisms that populate the Earth. Producers constitute the first link in food prices and form the basis of ecological pyramids.

2.Consumers(from Latin consumo - consume), or consumers, are heterotrophic organisms that feed on ready-made organic matter. Consumers themselves cannot build organic matter from inorganic matter and obtain it in finished form by feeding on other organisms. In their organisms, they transform organic matter into specific forms of proteins and other substances, and release waste generated during their life into the environment.

Grasshopper, hare, antelope, deer, elephant, etc. herbivores are consumers of the first order. A toad grabbing a dragonfly, a ladybug feeding on aphids, a wolf hunting a hare - all these are second-order consumers. A stork eating a frog, a kite carrying a chicken into the sky, a snake swallowing a swallow are consumers of the third order.

3. Decomposers(from Latin reducens, reducentis - returning, restoring) - organisms that destroy dead organic matter and transform it into inorganic substances, which, in turn, are absorbed by other organisms (producers).

The main decomposers are bacteria, fungi, protozoa, i.e. heterotrophic microorganisms found in the soil. If their activity decreases (for example, when humans use pesticides), the conditions for the production process of plants and consumers worsen. Dead organic remains, be it a tree stump or the corpse of an animal, do not disappear into nowhere. They are rotting. But dead organic matter cannot rot on its own. Reducers (destructors, destroyers) act as “gravediggers”. They oxidize dead organic residues to C0 2, H 2 0 and simple salts, i.e. to inorganic components, which can again be involved in the cycle of substances, thereby closing it.