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Introduction

1. Biocenosis - general information and concepts

2. The structure of the biocenosis

3. Modern problems of biocenoses and ways to solve them

Conclusion

Bibliography

Introduction

Biocenosis is a historically established set of animals, plants, fungi and microorganisms that inhabit a relatively homogeneous living space (a certain area of ​​​​land or water), and are interconnected and their environment. The concept of "biocenosis" is one of the most important in ecology, since it follows from it that living beings form complexly organized systems on Earth, outside of which they cannot exist stably.

Biocenosis is one of the main objects of ecology research. Problems of sustainability of biocenoses, a decrease in the number of populations, the disappearance of entire species of living organisms are acute problems facing humanity today. Therefore, the study of biocenoses, their structure and stability conditions is an important ecological task, which has been and continues to be given great attention by ecologists of all countries of the world, including Russian scientists.

In this work, I will dwell in detail on such issues as the properties and structure of the biocenosis, the conditions for their stability, as well as the main modern problems and ways to solve them. It should be noted that in the mind of a person who is not a specialist in the field of ecology, there is confusion in the concepts of "biocenosis", "ecosystem", "biogeocenosis", "biosphere", so I will briefly dwell on the similarities and differences between these concepts and their relationships. Biocenosis is one of the main objects of ecology research. Ecologists of all countries of the world, including Russian scientists, have paid and continue to pay great attention to the study of biocenoses. In the process of working on the abstract, I used textbooks written by well-known foreign ecologists: Yu. Odum, V. Tishler; and Russian authors: Korobkin V.I., Peredelsky L.V., as well as modern electronic resources indicated in the list of references.

1. Biots enosis - general information and concepts

Biocenosis (from the Greek vyapt - “life” and kpint - “general”) is a historically established set of animals, plants, fungi and microorganisms that inhabit a relatively homogeneous living space (a certain area of ​​\u200b\u200bland or water area), and interconnected and their environment. Biocenoses arose on the basis of the biogenic cycle and provide it in specific natural conditions. Biocenosis is a dynamic system capable of self-regulation, the components of which (producers, consumers, decomposers) are interconnected.

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).

The concept of "biocenosis" is one of the most important in ecology, since it follows from it that living beings form complexly organized systems on Earth, outside of which they cannot exist stably. The main function of the community is to ensure balance in the ecosystem based on a closed cycle of substances.

The composition of biocenoses can include thousands of species of various organisms. But not all of them are equally significant. The removal of some of them from the community does not have a noticeable effect on them, while the removal of others leads to significant changes.

Some types of biocenosis can be represented by numerous populations, while others are small. The scales of biocenotic groupings of organisms are very different - from communities of lichen pillows on tree trunks or a decaying stump to the population of entire landscapes: forests, steppes, deserts, etc.

The organization of life at the biocenotic level is subject to hierarchy. With an increase in the scale of communities, their complexity and the proportion of indirect, indirect relationships between species increase.

Natural associations of living beings have their own laws of functioning and development, i.e. are natural systems.

Thus, being, like organisms, structural units of living nature, biocenoses, nevertheless, are formed and maintain their stability on the basis of other principles. They are systems of the so-called frame type - without special control and coordinating centers, and are also built on numerous and complex internal connections.

The most important features of systems related to the supraorganismal level of life organization, for example, according to the classification of the German ecologist W. Tischler, are the following:

1) Communities always arise, are made up of ready-made parts (representatives of various species or entire complexes of species) that are present in the environment. In this way their origin differs from the formation of a separate organism, which occurs through the gradual differentiation of the simplest initial state.

2) Parts of the community are interchangeable. Parts (organs) of any organism are unique.

3) If in a whole organism constant coordination and consistency of the activity of its organs, cells and tissues is maintained, then the supraorganismal system exists mainly due to the balancing of oppositely directed forces.

4) Communities are based on the quantitative regulation of the number of some species by others.

5) The maximum size of an organism is limited by its internal hereditary program. The dimensions of supraorganismal systems are determined by external causes.

A homogeneous natural living space (part of the abiotic environment) occupied by a biocenosis is called a biotope. It can be a piece of land or a reservoir, a seashore or a mountainside. Biotope is an inorganic environment, which 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 tussocks in a swamp or a decaying stump to the population of entire landscapes. So, on land, one can distinguish the biocenosis of the upland (not flooded with water) meadow, the biocenosis of the white moss pine forest, the biocenosis of the feather grass steppe, the biocenosis of the wheat field, etc.

There are concepts of "species richness" and "species diversity" of biocenoses. Species richness is a common set of community species, which is expressed by a list of representatives of different groups of organisms. Species diversity is an indicator that reflects not only the qualitative composition of the biocenosis, but also the quantitative relationships of species.

There are poor and species-rich biocenoses. The species composition of biocenoses, in addition, depends on the duration of their existence, the history of each biocenosis. Young, just emerging communities usually include a smaller set of species than long-established, mature ones. Biocenoses created by man (fields, gardens, orchards) are also poorer in species than natural systems similar to them (forest, steppe, meadow). The monotony and species poverty of agrocenoses is supported by a special complex system of agrotechnical measures.

Almost all terrestrial and most aquatic biocenoses include microorganisms, plants, and animals in their composition. The stronger the differences between two neighboring biotopes, the more heterogeneous the conditions at their boundaries and the stronger the boundary effect. The number of one or another group of organisms in biocenoses strongly depends on their size. The smaller the individuals of species, the higher their abundance in biotopes.

Groups of organisms of different sizes live in a biocenosis at different scales of space and time. For example, the life cycles of unicellular organisms can take place within an hour, while the life cycles of large plants and animals stretch for decades.

Naturally, in all biocenoses, the smallest forms - bacteria and other microorganisms - predominate numerically. In each community, it is possible to single out a group of main, most numerous species in each size class, the relationships between which are decisive for the functioning of the biocenosis as a whole. Species that prevail in terms of numbers (productivity) are the dominants of the community. Dominants dominate the community and constitute the "species core" of any biocenosis.

For example, when studying a pasture, it was found that the maximum area in it is occupied by a plant - bluegrass, and among the animals grazing there, there are most of all cows. This means that bluegrass dominates among producers, and cows dominate among consumers.

In the richest biocenoses, almost all species are few in number. In tropical forests, it is rare to find several trees of the same species side by side. In such communities, outbreaks of mass reproduction of individual species do not occur; biocenoses are highly stable.

The totality of all types of a community constitutes its biodiversity. Usually, the community consists of several main species with high abundance and many rare species with low abundance.

Biodiversity is responsible for the equilibrium state of the ecosystem, and, consequently, for its sustainability. A closed cycle of nutrients (biogens) occurs only due to biological diversity.

Substances that are not assimilated by some organisms are assimilated by others, so the output of biogens from the ecosystem is small, and their constant presence ensures the balance of the ecosystem.

Human activity greatly reduces the diversity in natural communities, which requires forecasts and foresight of its consequences, as well as effective measures to maintain natural systems.

1.1 Biocenosis, ecosystem, biosphere

Ecosystem (from other Greek pkpt - dwelling, location and ueufzmb - system) - a biological system consisting of a community of living organisms (biocenosis), their habitat (biotope), a system of connections that exchanges matter and energy between them. Thus, the biocenosis is the main component of the ecosystem, its biotic component.

The basis of the ecological view of the world is the idea that every living being is surrounded by many different factors that affect it, forming in a complex its habitat - a biotope. Consequently, a biotope is a piece of territory that is homogeneous in terms of living conditions for certain types of plants or animals (the slope of a ravine, a city forest park, a small lake or part of a large one, but with homogeneous conditions - the coastal part, the deep-water part).

Organisms characteristic of a particular biotope constitute a life community, or biocenosis (animals, plants and microorganisms of a lake, meadow, coastal strip).

The biocenosis forms a single whole with its biotope, which is called the ecological system (ecosystem). An anthill, a lake, a pond, a meadow, a forest, a city, a farm can serve as an example of natural ecosystems. A classic example of an artificial ecosystem is a spaceship. biocenosis species spatial trophic

Close to the concept of an ecosystem is the concept of biogeocenosis. Supporters of the ecosystem approach in the West, incl. Y.Odum consider these concepts to be synonyms. However, a number of Russian scientists do not share this opinion, seeing a number of differences. Of particular importance for the identification of ecosystems are the trophic relationships of organisms that regulate the entire energy of biotic communities and the ecosystem as a whole.

Attempts to create a classification of the ecosystems of the globe have been made for a long time, but there is no convenient, universal classification yet. The thing is that because of the huge variety of types of natural ecosystems, because of their lack of rank, it is very difficult to find a single criterion based on which such a classification can be developed.

If a puddle, a hummock in a swamp, and a sand dune with established vegetation can be a separate ecosystem, then, naturally, all possible variants of hummocks, puddles, etc. can be calculated. does not seem possible. Therefore, ecologists decided to focus on large combinations of ecosystems - biomes. A biome is a large biosystem that is characterized by some dominant type of vegetation or other landscape feature. According to the American ecologist R. Whittaker, the main type of community on any continent, distinguished by the physiognomic characteristics of vegetation, is the biome. Moving from the north of the planet to the equator, nine main types of terrestrial biomes can be distinguished: tundra, taiga, temperate deciduous forest biome, temperate steppe, Mediterranean mud vegetation, desert, tropical savanna and grassland biome, tropical or spiny woodland, tropical forest biome .

The main components of ecosystems are:

1) non-living (abiotic) environment. These are water, minerals, gases, as well as organic substances and humus;

2) biotic components. These include: producers or producers (green plants), consumers, or consumers (living creatures that feed on producers), and decomposers, or decomposers (microorganisms).

The biomass created by organisms (the substance of the bodies of organisms) and the energy contained in them are transferred to other members of the ecosystem: animals eat plants, these animals are eaten by other animals. This process is called the food or trophic chain. In nature, food chains often intersect to form a food web. Examples of food chains: plant - herbivore - predator; cereal - field mouse - fox, etc. and the food web are shown in fig. 1.

Rice. 1. Food web and direction of matter flow

The biosphere is the shell of the Earth, inhabited by living organisms, under their influence and occupied by the products of their vital activity. The biosphere is the global ecosystem of the Earth. It penetrates the entire hydrosphere, the upper part of the lithosphere and the lower part of the atmosphere, that is, it inhabits the ecosphere. The biosphere is the totality of all living organisms. It is home to over 3,000,000 species of plants, animals, fungi and bacteria. Man is also a part of the biosphere, his activity surpasses many natural processes.

The state of equilibrium in the biosphere is based on the interaction of biotic and abiotic environmental factors, which is maintained due to the continuous exchange of matter and energy between all components of ecosystems.

In closed cycles of natural ecosystems, along with others, the participation of two factors is mandatory: the presence of decomposers and the constant supply of solar energy. There are few or no decomposers in urban and artificial ecosystems, so liquid, solid and gaseous wastes accumulate, polluting the environment.

1.3 History of the study of biocenosis

At the end of the 70s. 19th century the German hydrobiologist Karl Möbius studied the complexes of benthic animals - clusters of oysters (oyster banks). He observed that together with oysters there were also such animals 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, Möbius called biocenoses. The term "biocenosis" (from the Greek bios - life and koinos - general) was introduced by him into scientific literature in 1877 in the book "Die Auster und die Austernwirthschaft" to describe all organisms that inhabit a certain territory (biotope), and their relationships.

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 of an important direction in ecology, biocenology (ecology of communities), were laid.

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" (community). However, strictly speaking, the term "community" is not synonymous with the term "biocenosis". If the biocenosis can be called a multi-species community, then the population (an integral part of the biocenosis) is a single-species community.

2. The structure of the biocenosis

The structure of the biocenosis is multifaceted, and when studying it, various aspects are distinguished. Based on this, the structures of the biocenosis are divided into the following types:

1) specific;

2) spatial, in turn subdivided into vertical (tiered) and horizontal (mosaic) organization of the biocenosis;

3) trophic.

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

The composition of the biocenosis includes a set of plants in a certain area - phytocenosis; the totality of animals living within a phytocenosis is a zoocenosis; microbiocenosis - a set of microorganisms that inhabit the soil. Sometimes, as a separate constituent element, mycocenosis, a collection of fungi, is included in the biocenosis. Examples of biocenoses are deciduous, spruce, pine or mixed forest, meadow, swamp, 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 water bodies, where they serve as an important food source for fish and some other animals. At a young age, they are part of the aquatic biocenosis, and in adulthood they lead a terrestrial lifestyle, i.e. act as elements of land biocenoses. Hares can eat in the meadow, but live in the forest. The same applies to many species of forest birds that seek food not only in the forest, but also in adjacent meadows or swamps.

2.1 Species structure of biocenosis

The species structure of a biocenosis is a set 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 forests.

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

The number of species (species diversity) in different biocenoses is different and depends on their geographical location. The most well-known pattern of change in species diversity is its decrease from the tropics towards high latitudes. The closer to the equator, the richer and more diverse 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 rainforests of the Amazon Basin, on an area of ​​about 1 hectare, up to 400 trees of more than 90 species can be counted. In addition, many trees serve as a support for other plants. Up to 80 species of epiphytic plants grow on the branches and trunk of each tree.

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

Alpine and Arctic deserts are the poorest biocenoses in terms of species, and tropical forests are the richest. Panama's rainforests are home to three times as many species of mammals and birds as Alaska.

Biocenoses are not isolated from each other. Although it is visually possible to distinguish one plant community from another, for example, the biocenosis of a dry forest from the biocenosis of a moist meadow, which is replaced by a swamp, it is quite difficult to draw a clear boundary between them. Almost everywhere there is a kind of transitional strip of various widths and lengths, because rigid, sharp boundaries in nature are a rare exception. They are typical mainly for communities subject to intense anthropogenic impact.

In the early 30s. 20th century the American naturalist A. Leopold proclaimed the need to take into account the so-called "edge effect" in the activities of the hunting economy. In this case, the edge was understood not only as the outskirts of the forest, but also as any border between two biocenoses, even between two arrays of different agricultural crops. On both sides of this conditional line, the relative species diversity of plants and animals increases, fodder and protective conditions for game improve, the disturbance factor weakens, and most importantly, this zone has increased productivity. Such a transitional strip (or zone) between adjacent physiognomically distinct communities is called an ecotone.

More or less sharp boundaries between biocenoses can be observed only in cases of a sharp change in the factors of the abiotic environment. For example, such boundaries exist between water and terrestrial biocenoses, in places where there is a sharp change in the mineral composition of the soil, etc. Often the number of species in an ecotone exceeds their number in each of the adjacent biocenoses. Such a tendency to increase the diversity and density of living organisms at the boundaries of biocenoses is called the marginal (edge, boundary) effect. The edge effect is most clearly manifested in the zones separating the forest from the meadow (the zone of shrubs), the forest from the swamp, and so on.

2.2 Spatial structure of the biocenosis

Species can be distributed in different ways in space according to their needs and habitat conditions. Such a distribution of the species that make up the biocenosis in space is called the spatial structure of the biocenosis. Distinguish between vertical and horizontal structures.

1) The vertical structure of the biocenosis is formed by its individual elements, special layers, which are called tiers. Tier - co-growing groups of plant species, differing 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. 2).

The first, arboreal, tier usually consists of tall trees with high-lying foliage, which is well lit by the sun. Unused light can be absorbed by the trees forming the second, substory, tier.

Rice. 2. Layers of forest biocenosis

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

The undergrowth layer includes young low (from 1 to 5 m) trees, which in the future will be able to enter the first layer. 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 a grass-shrub layer. These include forest herbs and shrubs: lily of the valley, oxalis, strawberries, lingonberries, blueberries, ferns.

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

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

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

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

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

There are many examples of such a distribution: these are numerous herds of zebras, antelopes, elephants in the savannah, coral colonies on the seabed, schools of marine fish, flocks of migratory birds; thickets of reeds and aquatic plants, accumulations of mosses and lichens on the soil in the 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 is the smallest structural unit of the horizontal division of the community, which includes all tiers. Almost every community includes a complex of microcommunities or microcenoses.

Micro-grouping - concentration of individuals of one or several species within a tier, intratier mosaic spots. For example, in the moss layer, various patches of mosses can be distinguished with the dominance of one or several species. Blueberry, blueberry-sour, blueberry-sphagnum microgroups occur in the grass-shrub layer.

The presence of mosaics is essential to the life of the community. Mosaic allows more complete use of various types of microhabitats. Individuals forming groups are characterized by high survival rate, they use food resources most efficiently. This leads to an increase and diversity of species in the biocenosis, contributes to its stability and viability.

2.3 Trophic structure of biocenosis

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

In the biocenosis, three groups of organisms are distinguished.

1. Producers (from lat. producens - producing) - organisms that synthesize from inorganic substances (mainly water and carbon dioxide) all the organic substances necessary for life using solar energy (green plants, cyanobacteria and some other bacteria) or energy oxidation of inorganic substances (sulfur bacteria, iron bacteria, etc.). Usually, producers are green chlorophyll-bearing plants (autotrophs) that provide primary production. The total dry matter weight of phytomass (plant mass) is estimated at 2.42 x 1012 tons. This is 99% of the total living matter of the earth's surface. And only 1% falls on the share of heterotrophic organisms. Therefore, only the vegetation of the planet Earth is obliged to the existence of life on it. It was green plants that created the necessary conditions for the appearance and existence of various prehistoric animals, and then humans. Dying, the plants accumulated energy in deposits of coal, peat and even oil.

Producing plants provide man with food, raw materials for industry, medicines. They purify the air, trap dust, soften the temperature regime of the air, muffle the noise. Thanks to vegetation, there is a huge variety of animal organisms that inhabit the Earth. Producers make up the first link in the food price and underlie the ecological pyramids.

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

Grasshopper, hare, antelope, deer, elephant, i.e. herbivorous animals are consumers of the first order. A toad that seizes a dragonfly, a ladybug that feeds on aphids, a wolf that hunts 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. Reducers (from lat. reducens, reducentis - returning, restoring) - organisms that destroy dead organic matter and turn it into inorganic substances, and they, in turn, are absorbed by other organisms (producers).

The main decomposers are bacteria, fungi, protozoa, i.e. soil heterotrophic microorganisms. If their activity decreases (for example, when pesticides are used by humans), the conditions for the production process of plants and consumers worsen. Dead organic remains, whether it be a tree stump or the corpse of an animal, do not disappear into nowhere. They are subject to decay. But dead organics cannot rot on their own. Reducers (destructors, destroyers) act as "gravediggers". They oxidize dead organic residues to CO 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.

3. Modern problems and ways to solve them

The most acute problem of biocenoses is the reduction of populations of various living organisms up to the disappearance of entire species of animals, plants and microorganisms. This leads to a violation of the stability of biocenoses and poses a threat to the entire biosphere of the planet.

Each species participates in the circulation of substances, maintains a dynamic balance in natural ecosystems. Therefore, the loss of any biological species is highly undesirable for the biosphere.

The loss of species occurred as a result of evolutionary processes. Due to human activity, the biological resources of the planet are being lost much faster. Tens of thousands of plant and animal species are under threat of extinction. The reasons for this situation are:

1) loss of habitat: destruction of forests, drainage of swamps and floodplain lakes, plowing of steppes, change and shallowing of river beds, reduction in the area of ​​sea estuaries suitable for nesting, molting and wintering of waterfowl, road construction, urbanization and other changes resulting from human economic activity;

2) environmental pollution with toxic chemicals and xenobiotics, oil and oil products, salts of heavy metals, municipal solid waste;

3) the spread of introduced species of plants and animals, actively capturing vast territories and displacing the natural inhabitants of ecosystems. The unintentional, accidental dispersal of animals intensified with the development of transport;

4) ruthless exploitation of natural resources - minerals, soil fertility, aquatic ecosystems, overfishing of animals, birds and hydrobionts.

To protect endangered species, it is necessary to take active, sometimes urgent measures. One of the most effective methods of animal protection is the creation of reserves or sanctuaries. On the territory of the Russian Federation, there are more than 150 reserves in which a large number of animals have been saved. Among them are the Amur tiger, saiga, goral, Bukhara deer, kulan and others. Zoos located throughout the country help to breed endangered species of animals.

In order to preserve and increase the number of rare species, states on all continents of the Earth adopt laws regarding the protection and use of wildlife. In the Russian Federation, such a law was adopted on June 25, 1980. To account for rare species, both in Russia and in other countries of the world, the so-called Red Books are being created. Endangered species of animals around the world need a separate account; for this, the International Red Book has been created.

It is necessary to rationally use natural resources, including in agriculture. Limit deforestation, as well as hunting and fishing, and completely ban rare and endangered species.

Conclusion

Biocenosis is one of the main objects of ecology research. Biocenosis is a set of populations of plants, animals and microorganisms. The main function of the biocenosis is to ensure balance in the ecosystem based on a closed circulation of substances. The place occupied by a biocenosis is called a biotope. Types of structures of the biocenosis: species, spatial (vertical (tiered) and horizontal (mosaic) organization of the biocenosis) and trophic. The species structure of the biocenosis covers all the species living in it. The spatial structure includes a vertical structure - tiers and a horizontal one - 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 the 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 the biocenosis and ecosystem is usually displayed by graphical models in the form of ecological pyramids. There are ecological pyramids of numbers, biomass and energy. The rate of fixation of solar energy determines the productivity of biocenoses. The set of environmental factors within which a species lives is called an ecological niche.

Humanity is now facing the acute problem of the extinction of species of various living organisms, leading to a violation of the stability of biocenoses and the biosphere as a whole. To prevent the decline in populations and the extinction of entire species, it is necessary to take urgent and active measures: listing endangered species in the Red Books; creation of nature reserves and national parks; restriction of hunting, fishing and deforestation; rational use of all natural resources.

Bibliography

1. Korobkin V.I., Peredelsky L.V. Ecology. - R.-on-Don, 2001 - 576 p.

2. Odum Yu. Ecology: in 2 vols. T. 1 - M., 1986 - 328 p.; T. 2 - M., 1986 - 376 p.

3. Articles from the electronic resource "Wikipedia": Biocenosis, Biosphere, Ecosystem

4. Tishler V. Agricultural ecology. - M., 1971 - 455 p.

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The concept of "productivity of ecosystems", its types, classification of ecosystems by productivity. The four successive steps (or stages) of the organic matter production process. Species composition and saturation of the biocenosis. Ecological standardization.

test, added 09/27/2009


The concept of trophic structure as the totality of all food dependencies in an ecosystem. Community activity factors. Types of nutrition of living organisms. Distribution of ranges of the solar spectrum. Scheme of the cycle of matter and the flow of energy in the ecosystem.

presentation, added 02/08/2016


History of development of ecology. Species and spatial structure of the biocenosis. Natural resources of the earth. Types of pollution of the hydrosphere and biosphere by production and consumption waste. The role of biotechnology and government agencies in environmental protection.

test, added 06/02/2010


Acquaintance with the interpretation of the concept of biocenosis; identification of its constituent parts and main participants. Description of the essence and methods of environmental risk management, familiarization with its anthropogenic, natural and man-made factors of occurrence.

test, added 04/27/2011


Consideration of the principles of the theory of Bari Commoner, the laws of minimum, necessity, pyramid of energy, the concept of succession (consistent change of communities under the influence of time), biocenosis, tolerance, environmental resistance, sustainability of the natural community.

At the beginning of the twentieth century, biologists who studied individual objects of wildlife came to the conclusion that integral results that adequately reflect the laws of the natural environment can be obtained only when considering natural phenomena and organisms inhabiting the natural environment as an integral object, as a natural whole. The idea was born of the presence in nature of natural complexes in which living organisms are connected by a large number of various connections.

For the first time, the German biologist Karl August Möbius drew attention to the possibility of isolating such complexes. In the late 70s of the XIX century, he studied the clusters of oysters living on the sea slopes. Unlike many naturalists of his time, Möbius was interested not only in oysters themselves, but also in their living conditions. Such a complex method of research in biology has not yet been used. By measuring and examining various environmental factors, Möbius came to the conclusion that they are strictly specific for each oyster habitat. Moreover, along with oysters, such diverse animals as starfish, echinoderms, bryozoans, worms, ascidians, sponges and others were found here. The scientist concluded that it is no coincidence that all these animals live together, in the same habitat. They need the same conditions as numerous oysters. Thus, 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, Möbius called biocenoses. Term biocenosis (from the Greek "bios" - life and "koinos" - general, to make something general) was first introduced by him into scientific literature in 1877.

Biocenosis is a historically established grouping of plants, animals, fungi and microorganisms, inhabiting a relatively homogeneous living space (a piece of land or a reservoir).

So, each biocenosis consists of a certain set of living organisms belonging to different species. But we know that individuals of the same species are united in natural systems, which are called populations. That's why biocenosis can also be defined and as a set of populations of all types of living organisms inhabiting common habitats.

“Each habitat of oysters,” Mobius wrote in his work, “is a community of living beings, a collection of species and an accumulation of individuals who find here everything necessary for their growth and existence, that is, appropriate soil, enough food, proper salinity and favorable for their development. temperature... Science, however, has no word by which such a community of living beings could be designated; there is no word for a community in which the sum of species and individuals, constantly limited and subjected to selection under the influence of external conditions of life, by reproduction continuously owns a certain definite territory. I propose the word "biocenosis" for such a community.

In modern ecological literature, the term biocenosis is usually used as a synonym for the term community.

The merit of Möbius is that he not only established the presence of organic communities and proposed the name "biocenosis" for them, but also managed to reveal many patterns of their formation and development.

Thus, the foundations of an important direction in ecology, biocenology, were laid.

The composition of the biocenosis includes a set of plants in a certain area - phytocenosis (from the Greek "phyton" - a plant), a set of animals living within a phytocenosis - zoocenosis (from the Greek "zoon" - animal), microbiocenosis - a collection of microorganisms that inhabit the soil and mycocenosis (from the Greek "mykes" - mushroom) - a collection of mushrooms. Examples of biocenoses are deciduous, spruce, pine or mixed forest, meadow, swamp, etc.

Each biocenosis develops within a homogeneous space, which is characterized by a certain combination of abiotic factors. These may include the amount of incoming solar radiation, temperature, humidity, chemical and mechanical composition of the soil, its acidity, terrain, etc. Such a homogeneous space (part of the abiotic environment) occupied by a biocenosis is called biotope. It can be any piece of land or water, a seashore or a mountainside. A biotope is an inorganic environment, which is a necessary condition for the existence of a biocenosis. There is a close interaction between biocenosis and biotope.

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

A specific biocenosis includes not only organisms that constantly live in a certain area, but also those that have a significant impact on its life.

For example, many insects breed in water bodies, where they serve as an important food source for fish and some other animals. At a young age, they are part of the aquatic biocenosis, and in adulthood they lead a terrestrial lifestyle, i.e. act as elements of land biocenoses. Hares can eat in the meadow, but live in the forest. The same applies to many species of forest birds that seek food not only in the forest, but also in adjacent meadows or swamps.

In the aquatic environment, biocenoses are usually distinguished in accordance with the ecological subdivision of parts of water bodies - the biocenosis of coastal sandy or silty soils, the biocenosis of the intertidal zone of the sea, the biocenosis of large aquatic plants of the coastal zone of the lake, etc.

Biocenosis, as an open system, receives solar energy, gases, atmosphere, water, and mineral elements of the soil at its “input”. At the "output" - heat, oxygen, carbon, biogenic substances carried away by water. However, the main "product" of the biocenosis is living products - plant and animal biomass, and inanimate and dead matter transformed in the biotope - a source of various minerals.

Biocenosis (from Greek bios - life, koinos - general) is an organized group of interconnected populations of plants, animals, fungi and microorganisms living together in the same environmental conditions.

The concept of "biocenosis" was proposed in 1877 by the German zoologist K. Möbius. Moebius, studying oyster jars, came to the conclusion that each of them is a community of living beings, all members of which are in close relationship. Biocenosis is a product of natural selection. Its survival, stable existence in time and space depends on the nature of the interaction of the constituent populations and is possible only with the obligatory receipt of the radiant energy of the Sun from outside.

Each biocenosis has a certain structure, species composition and territory; it is characterized by a certain organization of food relations and a certain type of metabolism

But no biocenosis can develop on its own, outside and independently of the environment. As a result, certain complexes, aggregates of living and non-living components, are formed in nature. The complex interactions of their individual parts are supported on the basis of versatile mutual fitness.

A space with more or less homogeneous conditions, inhabited by one or another community of organisms (biocenosis), is called a biotope.

In other words, a biotope is a place of existence, a habitat, a biocenosis. Therefore, a biocenosis can be considered as a historically established complex of organisms, characteristic of a particular biotope.

Any biocenosis forms a dialectical unity with a biotope, a biological macrosystem of an even higher rank - a biogeocenosis. The term "biogeocenosis" was proposed in 1940 by V.N. Sukachev. It is practically identical to the term "ecosystem" widely used abroad, which was proposed in 1935 by A. Tensley. There is an opinion that the term "biogeocenosis" to a much greater extent reflects the structural characteristics of the macrosystem under study, while the concept of "ecosystem" primarily includes its functional essence. In fact, there is no difference between these terms. Undoubtedly, V.N. Sukachev, formulating the concept of "biogeocenosis", combined in it not only the structural, but also the functional significance of the macrosystem. According to V.N. Sukachev, biogeocenosis- This set of homogeneous natural phenomena over a known extent of the earth's surface- atmosphere, rocks, hydrological conditions, vegetation, fauna, the world of microorganisms and soil. This set is distinguished by the specifics of the interactions of its constituent components, their special structure and a certain type of exchange of matter and energy between themselves and with other natural phenomena.

Biogeocenoses can be of various sizes. In addition, they are very complex - it is sometimes difficult to take into account all the elements, all the links in them. These are, for example, such natural groupings as a forest, a lake, a meadow, etc. An example of a relatively simple and clear biogeocenosis can be a small reservoir, a pond. Its non-living components include water, substances dissolved in it (oxygen, carbon dioxide, salts, organic compounds) and soil - the bottom of a reservoir, which also contains a large number of various substances. The living components of the reservoir are divided into producers of primary products - producers (green plants), consumers - consumers (primary - herbivores, secondary - carnivores, etc.) and decomposers - destructors (microorganisms), which decompose organic compounds to inorganic. Any biogeocenosis, regardless of its size and complexity, consists of these main links: producers, consumers, destroyers and components of inanimate nature, as well as many other links. Connections of various orders arise between them - parallel and intersecting, tangled and intertwined, etc.

In general, biogeocenosis represents an internal contradictory dialectical unity that is in constant motion and change. “Biogeocenosis is not the sum of biocenosis and the environment,” N.V. Dylis points out, “but a holistic and qualitatively isolated phenomenon of nature, acting and developing according to its own laws, the basis of which is the metabolism of its components.”

Living components of biogeocenosis, i.e. balanced animal and plant communities (biocenoses), are the highest form of existence of organisms. They are characterized by a relatively stable composition of fauna and flora and have a typical set of living organisms that retain their main features in time and space. The stability of biogeocenoses is supported by self-regulation, that is, all elements of the system exist together, never completely destroying each other, but only limiting the number of individuals of each species to a certain limit. That is why such relationships have historically developed between animal, plant and microorganism species that ensure development and keep their reproduction at a certain level. Overpopulation of one of them may arise for some reason as an outbreak of mass reproduction, and then the established ratio between the species is temporarily disturbed.

To simplify the study of biocenosis, it can be conditionally divided into separate components: phytocenosis - vegetation, zoocenosis - wildlife, microbiocenosis - microorganisms. But such fragmentation leads to an artificial and actually incorrect separation from a single natural complex of groups that cannot exist independently. In no habitat can there be a dynamic system that would consist only of plants or only of animals. Biocenosis, phytocenosis and zoocenosis must be considered as biological units of different types and stages. This view objectively reflects the real situation in modern ecology.

In the conditions of scientific and technological progress, human activity transforms natural biogeocenoses (forests, steppes). They are being replaced by sowing and planting of cultivated plants. This is how special secondary agrobiogeocenoses, or agrocenoses, are formed, the number of which on Earth is constantly increasing. Agrocenoses are not only agricultural fields, but also shelterbelts, pastures, artificially regenerated forests in clearings and conflagrations, ponds and reservoirs, canals and drained swamps. Agrobiocenoses in their structure are characterized by a small number of species, but their high abundance. Although there are many specific features in the structure and energy of natural and artificial biocenoses, there are no sharp differences between them. In a natural biogeocenosis, the quantitative ratio of individuals of different species is mutually dependent, since it has mechanisms that regulate this ratio. As a result, a stable state is established in such biogeocenoses, maintaining the most favorable quantitative proportions of its constituent components. There are no such mechanisms in artificial agrocenoses; there, a person completely took care of streamlining the relationship between species. Much attention is paid to the study of the structure and dynamics of agrocenoses, since in the foreseeable future there will be practically no primary, natural, biogeocenoses.

1. Trophic structure of biocenosis

The main function of biocenoses - maintaining the circulation of substances in the biosphere - is based on the nutritional relationships of species. It is on this basis that organic substances synthesized by autotrophic organisms undergo multiple chemical transformations and eventually return to the environment in the form of inorganic waste products, again involved in the cycle. Therefore, with all the diversity of species that make up different communities, each biocenosis necessarily includes representatives of all three principal ecological groups of organisms - producers, consumers and decomposers . The completeness of the trophic structure of biocenoses is an axiom of biocenology.

Groups of organisms and their relationships in biocenoses

According to participation in the biogenic cycle of substances in biocenoses, three groups of organisms are distinguished:

1) Producers(producers) - autotrophic organisms that create organic substances from inorganic ones. The main producers in all biocenoses are green plants. The activity of producers determines the initial accumulation of organic substances in the biocenosis;

ConsumersIorder.

This trophic level is composed by direct consumers of primary production. In the most typical cases, when the latter is created by photoautotrophs, these are herbivorous animals. (phytophages). Species and ecological forms representing this level are very diverse and adapted to feeding on different types of plant food. Due to the fact that plants are usually attached to the substrate, and their tissues are often very strong, many phytophages have evolved a gnawing type of mouth apparatus and various adaptations for grinding and grinding food. These are the dental systems of the gnawing and grinding type in various herbivorous mammals, the muscular stomach of birds, which is especially well expressed in granivorous ones, and so on. n. The combination of these structures determines the possibility of grinding solid food. Gnawing mouth apparatus is characteristic of many insects, etc.

Some animals are adapted to feed on plant sap or flower nectar. This food is rich in high-calorie, easily digestible substances. The oral apparatus of species that feed in this way is arranged in the form of a tube, with the help of which liquid food is absorbed.

Adaptations to nutrition by plants are also found at the physiological level. They are especially pronounced in animals that feed on the coarse tissues of the vegetative parts of plants, which contain a large amount of fiber. Cellulolytic enzymes are not produced in the body of most animals, and the breakdown of fiber is carried out by symbiotic bacteria (and some protozoa of the intestinal tract).

Consumers partly use food to provide life processes (“breathing costs”), and partly build their own body on its basis, thus carrying out the first, fundamental stage in the transformation of organic matter synthesized by producers. The process of creation and accumulation of biomass at the consumer level is denoted as , secondary products.

ConsumersIIorder.

This level combines animals with a carnivorous type of food. (zoophages). Usually, all predators are considered in this group, since their specific features practically do not depend on whether the prey is a phytophage or a carnivore. But strictly speaking, only predators that feed on herbivorous animals and, accordingly, represent the second stage of the transformation of organic matter in food chains, should be considered second-order consumers. The chemicals that make up the tissues of an animal organism are quite homogeneous, so the transformation during the transition from one level of consumers to another is not as fundamental as the transformation of plant tissues into animals.

With a more careful approach, the level of consumers of the second order should be divided into sublevels according to the direction of the flow of matter and energy. For example, in the trophic chain "cereals - grasshoppers - frogs - snakes - eagles", frogs, snakes and eagles constitute successive sublevels of consumers of the second order.

Zoophages are characterized by their specific adaptations to the nature of their diet. For example, their mouthparts are often adapted for grasping and holding live prey. When feeding on animals that have dense protective covers, adaptations are developed for their destruction.

At the physiological level, adaptations of zoophages are expressed primarily in the specificity of the action of enzymes "tuned" to the digestion of food of animal origin.

ConsumersIIIorder.

The most important in biocenoses are trophic relationships. Based on these connections of organisms in each biocenosis, the so-called food chains are distinguished, which arise as a result of complex nutritional relationships between plant and animal organisms. Food chains unite directly or indirectly a large group of organisms into a single complex, interconnected by relationships: food - consumer. The food chain usually consists of several links. The organisms of the next link eat the organisms of the previous link, and thus the chain transfer of energy and matter is carried out, which underlies the cycle of substances in nature. With each transfer from link to link, a large part (up to 80 - 90%) of the potential energy is lost, dissipating in the form of heat. For this reason, the number of links (species) in the food chain is limited and usually does not exceed 4-5.

A schematic diagram of the food chain is shown in fig. 2.

Here, the food chain is based on species - producers - autotrophic organisms, mainly green plants that synthesize organic matter (they build their bodies from water, inorganic salts and carbon dioxide, assimilating the energy of solar radiation), as well as sulfuric, hydrogen and other bacteria that use for the synthesis of organic substances energy oxidation of chemicals. The next links in the food chain are occupied by consumer species-heterotrophic organisms that consume organic matter. Primary consumers are herbivorous animals that feed on grass, seeds, fruits, underground parts of plants - roots, tubers, bulbs and even wood (some insects). Secondary consumers include carnivores. Carnivores, in turn, are divided into two groups: feeding on mass small prey and active predators, often attacking prey larger than the predator itself. At the same time, both herbivores and carnivores have a mixed diet. For example, even with an abundance of mammals and birds, martens and sables also eat fruits, seeds and pine nuts, and herbivorous animals consume some amount of animal food, thus obtaining the essential amino acids of animal origin they need. Starting at the producer level, there are two new ways to use energy. First, it is used by herbivores (phytophages), which eat directly the living tissues of plants; secondly, they consume saprophages in the form of already dead tissues (for example, during the decomposition of forest litter). Organisms called saprophages, mainly fungi and bacteria, obtain the necessary energy by decomposing dead organic matter. In accordance with this, there are two types of food chains: the chains of eating and the chains of decomposition, fig. 3.

It should be emphasized that the food chains of decomposition are no less important than the chains of grazing. On land, these chains begin with dead organic matter (leaves, bark, branches), in water - dead algae, fecal matter and other organic residues. Organic residues can be completely consumed by bacteria, fungi and small animals - saprophages; in this case, gas and heat are released.

Each biocenosis usually has several food chains, which in most cases are difficult to intertwine.

Quantitative characteristics of biocenosis: biomass, biological productivity.

Biomass And biocenosis productivity

The amount of living matter of all groups of plant and animal organisms is called biomass. The rate of biomass production is characterized by the productivity of the biocenosis. There are primary productivity - plant biomass formed per unit time during photosynthesis, and secondary - biomass produced by animals (consumers) that consume primary products. Secondary production is formed as a result of the use by heterotrophic organisms of the energy stored by autotrophs.

Productivity is usually expressed in terms of mass per year in terms of dry matter per unit area or volume, which varies significantly in different plant communities. For example, 1 hectare of pine forest produces 6.5 tons of biomass per year, and a sugarcane plantation - 34-78 tons. In general, the primary productivity of the world's forests is the highest compared to other formations. A biocenosis is a historically established complex of organisms and is part of a more general natural complex - an ecosystem.

The rule of ecological pyramids.

All species that make up the food chain subsist on the organic matter created by green plants. At the same time, there is an important regularity associated with the efficiency of the use and conversion of energy in the process of nutrition. Its essence is as follows.

Only about 0.1% of the energy received from the Sun is bound in the process of photosynthesis. However, due to this energy, several thousand grams of dry organic matter per 1 m 2 per year can be synthesized. More than half of the energy associated with photosynthesis is immediately consumed in the process of respiration of the plants themselves. The other part of it is transferred through a number of organisms along food chains. But when animals eat plants, most of the energy contained in food is spent on various life processes, while turning into heat and dissipating. Only 5 - 20% of food energy passes into the newly built substance of the animal's body. The amount of plant matter that serves as the basis of the food chain is always several times greater than the total mass of herbivorous animals, and the mass of each of the subsequent links in the food chain also decreases. This very important rule is called ecological pyramid rule. The ecological pyramid, which is a food chain: cereals - grasshoppers - frogs - snakes - an eagle is shown in fig. 6.

The height of the pyramid corresponds to the length of the food chain.

The transition of biomass from the underlying trophic level to the overlying one is associated with the loss of matter and energy. On average, it is believed that only about 10% of the biomass and the energy associated with it passes from each level to the next. Because of this, the total biomass, production and energy, and often the number of individuals progressively decrease as one ascends the trophic levels. This regularity was formulated by Ch. Elton (Ch. Elton, 1927) as a rule ecological pyramids (Fig. 4) and acts as the main limiter for the length of food chains.

All wildlife that surrounds us - animals, plants, fungi and other living organisms, is a whole biocenosis or part of, for example, a regional biocenosis or a biocenosis of a separate part. All biocenoses are different in terms of conditions, and may differ in species of organisms and plants.

In contact with

Biocenosis is community, the totality of living organisms in the nature of a certain territorial area. The concept also includes environmental conditions. If a separate territory is taken, then within its limits there should be approximately the same climate. 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! 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 any particular area, Karl August Möbius 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 populations.
2. The biotic relationship between all components is stable.
3. Organisms adapt to each other and groups.
4. There is a biological cycle in the area.
5. Organisms interact with each other, so they are mutually necessary.

Components

The components of the 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, it is an inanimate part. In different parts of the continents, conditions will be different. The more severe the conditions, the fewer species will live on the territory. In the equatorial belt, the most favorable climate is warm and humid, so endemic species are most often found in such areas (many of them can be found on mainland Australia).

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, the types of biocenosis are classified according to the following criteria.

By spatial arrangement:

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

Origin:

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

By type of relationship species within the biocenosis:

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

Spatial structure of biocenosis

Natural biocenosis

Natural biocenosis is characterized by the fact that it is of natural origin. In the processes taking place in it, a person does not interfere. For example: the Volga river, forest, steppe, meadow, mountains. Unlike artificial ones, natural ones have a larger scale.

If a person interferes with the natural environment, then the balance between species is disturbed. 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".

Consider examples of natural biocenosis.

River

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

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

Forest

The forest is an 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, titmouse, woodpecker, chaffinch, cuckoo, oriole, black grouse, capercaillie, 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, kupyr, strawberry, blackberry, dandelion, snowdrop, violet, forget-me-not, lungwort, hazel and many other plants.

The forest biocenosis is represented by such mushrooms: boletus, boletus, white mushroom, grebe, fly agaric, oyster mushroom, puffball, chanterelle, butterdish, honey agaric, morel, russula, champignon, camelina, etc.

Natural and artificial biocenosis

Artificial biocenosis

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

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

Examples of artificial classification

For example, in a field, a greenhouse, a garden or a vegetable garden, a person breeds cultivated plants (vegetables, cereals, fruit-bearing 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 keep them from being eaten by pests, etc.

Forest belts are planted near fields, on the slopes of ravines, near railways and highways. They are needed near the fields in order to reduce evaporation, keep snow in the spring, i.e. to control the water regime of the earth. Trees also protect seeds from wind dispersal and soil from erosion.

On the slopes of ravines, trees are planted to prevent and slow down their growth, as the roots will hold the soil.

Trees along the roads are necessary in order to prevent snow, dust, sand from drifting the transport routes.

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

The horizontal structure of the biocenosis

The horizontal structure of the biocenosis differs from the longline 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. Diversity, abundance and richness of the living world varies by zone. In the zone of the Arctic deserts, in the Arctic climatic zone, the animal and plant world is scarce and poor. As you approach the rainforest zone, in the tropical climate zone, the number and diversity of species will increase. So we managed to trace the changes in the number of species within the biocenosis, and even the change in their structure (since they have to adapt to different climate conditions). This is a natural mosaic.

And artificial mosaicism arises under the influence of man on the environment. For example, deforestation, sowing meadows, draining swamps, etc. In a place where a person has 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 begin to differ.

Biocenosis

The concept of biogeocenosis and ecosystem

Conclusion

To summarize: the biocenosis has different classifications depending on the origin, relationships between organisms and location in space. They differ in territorial scope and species that live within them. Signs of biocenosis can be classified separately for each area.

STRUCTURE OF BIOCENOSIS

What are biocenoses

Groupings of cohabiting and mutually related organisms are calledbiocenoses. The adaptation of members of the biocenosis to living together is expressed in a certain similarity of requirements for the most important abiotic environmental conditions and regular relationships with each other.

The term "biocenosis" is more often used in relation to the population of territorial areas, which on land are distinguished by relatively homogeneous vegetation (usually along the boundaries of plant associations), for example, the biocenosis of the spruce forest, the biocenosis of the upland meadow, the white moss pine forest, the biocenosis of the feather grass steppe, wheat field, etc. ). This refers to the totality of living beings - plants, animals, microorganisms, adapted to cohabitation in a given territory. In the aquatic environment, biocenoses are distinguished that correspond to the ecological subdivisions of parts of water bodies, for example, biocenoses of coastal pebble, sandy or silty soils, 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 number or mass. There are poor and species-rich biocenoses. In the polar arctic deserts and northern tundras with extreme heat deficiency, in waterless hot deserts, in water bodies heavily polluted with sewage, wherever one or several environmental factors deviate far from the average level that is optimal for life, communities are severely depleted, since only few species can adapt to such extreme conditions. Wherever the conditions of the abiotic environment approach the optimal average for life, extremely species-rich communities arise. Examples of these are tropical forests, coral reefs with their diverse population, river valleys in arid arid 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 man (fields, vegetable gardens, orchards) are also poorer in species than natural systems similar to them (forest, steppe, meadow. However, even the most depleted 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 decaying silts). Species-rich natural communities include thousands and even tens of thousands of species united by a complex system of relationships.

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

The dominant species are dominants communities. For example, in our spruce forests, spruce dominates among trees, oxalis and other species dominate in the grass cover, in the bird population - kinglet, robin, chiffchaff, among mouse-like rodents - bank and red-gray voles, etc. However, not all dominant species equally affect the biocenosis. Among them are those that, by their vital activity, create the environment for the entire community to the greatest extent and without which, therefore, the existence of most other species is impossible. Such types are called edificators. The main edificators of terrestrial biocenoses are certain types of plants: in spruce forests - spruce, in pine forests - pine, in the steppes - sod grasses (feather grass, fescue, etc.). In some cases, animals can also be edificators. For example, in territories occupied by marmot colonies, it is their burrowing 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 relationships and serve as a reserve for replenishment and replacement of dominants, i.e. give stability to the biocenosis and ensure the reliability of its functioning in different conditions. The larger the reserve of such minor species in the community, the more likely it is that among them there will be those that can play the role of dominants under any changes in the environment.

The more specific 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 few in number.

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

2. Spatial structure .

The spatial structure of the biocenosis is determined before
just the addition of its plant part - phytocenosis, the distribution of ground and underground masses of plants. Phytocenosis often acquires a clear longline addition : The plants that assimilate the aboveground 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, tree, grass-shrub and moss layers are clearly distinguished. 5-6 tiers can also be distinguished in a broad-leaved forest: the first, or upper, tier is formed by trees of the first size (pedunculate oak, heart-shaped 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 undergrowth formed by shrubs (common hazel, brittle buckthorn, forest honeysuckle, European euonymus, etc.); the fourth consists of tall grasses (wrestlers, spreading boron, forest chistets, etc.); the fifth tier is composed of lower herbs (common goutweed, hairy sedge, long-term forest herb, etc.); in the sixth tier - the lowest grasses, such as European hoof.

In the forests, there are always inter-tier (out-tier) plants - these are algae and lichens on tree trunks and branches, higher spore and flowering epiphytes, lianas, etc. Rage allows plants to more fully use the light flux: under the canopy of tall plants, shade-tolerant, up to shade-loving ones can exist. , 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. Each tier in its own way participates in the creation of a phytoclimate and is adapted to a certain set of conditions.

The underground layering of phytocenoses is associated with different rooting depths of the plants that make up them, with the placement of the active part of the root systems. In the forests, one 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: inhabitants of the soil - geobium , ground, surface layer - herpetobium , , moss layer - bryobium, herbage_ - phyllobium, higher tiers - aerobium.

Dissection in the horizontal direction - mosaic. Mosaic due to a number of reasons: the heterogeneity of the microrelief, soils, the environment-forming influence of plants and their ecological features. It can occur as a result of animal activity (the formation of soil emissions and their subsequent overgrowth, the formation of anthills, trampling and grazing of the herbage by ungulates, etc.) or humans (selective logging, campfires, etc.), due to fallout of the forest stand 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 an initial ecological structure may have a different species composition, since in them the same ecological niches can be occupied by species similar in ecology, but far from related. Such species that perform the same , functions in similar biocenoses are called vicarious. For example, bison in the prairies of North America, antelopes in the savannahs 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 the biocenoses of different natural zones, the ratio of phytophages and saprophages regularly changes. In the steppe, semi-desert and desert regions, animal phytophages predominate over saprophages; in the forest communities of the temperate zone, on the contrary, saprophagy is more developed. The main type of animal nutrition in the depths of the ocean is predation , while in the illuminated, surface zone of the pelagial there are many filter feeders that consume phytoplankton or species with a mixed nature of nutrition.

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

The ratio of organisms in the biocenosisX.

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

1.Trophic connections occurs when one species feeds on another ­ gim - either living individuals, or their dead remains, or waste products. Dragonflies that catch other insects in flight, and dung beetles that feed on the droppings of large ungulates, and bees that collect plant nectar, enter into a direct trophic relationship with the species that provide food. In the case of competition between two species due to food objects, an indirect trophic relationship arises between them, since the activity of one is reflected in the supply of food to the other. Any effect of one species on the palatability 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 access weakened trees.

Topical and trophic connections are of the greatest importance in the biocenosis, they 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. Foric connections. This is the participation of one species in the distribution of another. Animals act as carriers. The transfer of seeds, spores, 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 the animal's body accidentally comes into contact with a plant whose seeds or fruit have special hooks, hooks, outgrowths (sequence, burdock). An active capture method is eating fruits and berries. Indigestible seeds are excreted by animals along with litter. Animal phoresia is prevalent mainly among small arthropods, especially in various groups of ticks. It is one of the ways of passive dispersal and is characteristic of species for which the transfer from one biotope to another is vital for conservation or prosperity. Dung beetles sometimes crawl with raised elytra, which are not able to fold because of the ticks that densely cover the body. Among large animals, phoresia is almost never found.

4. factory connections . This is a type of biocenotic relationship that a species enters into, using excretory products, or dead remains, or even living individuals of another species for its structures (fabrication). So birds use branches of trees, hair of mammals, grass, leaves, fluff and feathers of other bird species, etc. to build nests. The megahila bee places eggs and supplies in cups constructed from the soft leaves of various shrubs (rose hips, lilacs, acacias, etc.).