Throughout our lives, we are surrounded by animals, various plants, soil, air, water... We are all used to calling it the environment. In principle, this is correct, but the environment also varies. It may differ from whether this particular environment is made by man or exists on its own, what factors of living or non-living nature influence it. They also distinguish between ground-air, aquatic, organismal, and soil environments. We can safely call all this ecosystems, but what then is biogeocenosis? Let's find out!
Characteristics of biogeocenosis and its features
Biogeocenosis is an ecosystem in which natural phenomena (fauna, air, rocks, flora, etc.) have similar nature of mutual influence between each other, and are also combined by the exchange of energy and the circulation of substances. It consists of an ecotope (atmosphere and soil) and a biocenosis (animals, plants, various microorganisms). It turns out that biogeocenosis is a type of ecosystem? Yes, a biogeocenosis is an ecosystem, but not every ecosystem is a biogeocenosis. How can we understand this? For example, not all artificial ecosystems will be a biogeocenosis, since, firstly, a biogeocenosis can exist on land and nowhere else, and secondly, it has specifically designated boundaries that are determined by a phytocenosis (a plant community that is limited by the boundaries of one biotope).
If not phytocenosis, then biogeocenosis cannot exist. But when it is impossible to distinguish a phytocenosis, then the name “ecosystem” is already used. Based on the information received, we can conclude that phytocenosis and abiotic factors (factors of inanimate nature) are very important in the formation and existence of biogeocenosis. The most striking examples of biocenosis will be a forest, swamp, meadow, field, etc.
Varieties of biogeocenosis
Biogeocenosis also has its own subspecies. There are natural and artificial biogeocenoses. With natural everything is clear, it was formed without human intervention and over time, and quite a long time starting from 1000 years. But in artificial they distinguish:
- - created by people. It is man who determines the species composition, cares for, and processes the plants and animals located in a given biogeocenosis. A striking example of this ecosystem is a park.
- Agrobiocenosis. This ecosystem is also created by humans, but for agricultural activities. The most famous example for us is a field or plantation.
Properties of biocenosis
Like any ecosystem, biogeocenosis has its own properties:
- To begin with, this is a system that has developed during historical changes.
- Biogeocenosis can be both natural and artificial.
- It is characterized by the circulation of substances.
- It is capable of self-regulation, which is very important for maintaining a constant composition at the required level.
- The main source of energy is the Sun, and the biogeocenosis is open for energy output and input.
Most of these properties are also characteristic of an ecosystem, which helps to convince us that a biogeocenosis is an ecosystem.
Ecosystem characteristics
To define the concept of “ecosystem”, it is enough to re-read the term “biogeocenosis”. An ecosystem is a biological environment in which energy exchange and circulation of substances and all the phenomena of living and inanimate nature are interconnected in it. In fact, “biogeocenosis” is synonymous with the concept of “ecosystem”.
What does an ecosystem consist of?
The ecosystem consists of the same components as the biogeocenosis:
- Biocenosis.
- Ecotop.
Types of ecosystem
An ecosystem can be natural or artificial:
- Natural, formed under the influence of natural factors over a long period of time. People can influence this ecosystem. For example, a forest. In the forest, people take wood, collect mushrooms and berries, hunt animals, etc. But in such biological areas, the influence of natural factors suppresses the influence of people.
- Anthropogenic are ecosystems that are created and used by people for agricultural purposes. For example, pasture. In anthropogenic ecosystems, it is possible to preserve natural ecosystems in their original form, such as rivers or swamps.
Natural systems are distinguished from anthropogenic systems by the source of energy that provides them.
Among ecosystems, there is another classification of ecosystems:
- Autotrophic- these are systems that are energy-supplied, either due to the solar energy consumed by producers - photoautotrophic ecosystems, or due to the chemical energy of producers - chemoautotrophic ecosystems.
- Heterotrophic is a system that uses chemical energy, either created by man through energy devices, or together with carbon from organic matter.
Differences between ecosystem and biogeocenosis.
- Firstly, biogeocenosis is a special case of an ecosystem. After all, biogeocenosis is limited by phytocenosis, and when it cannot be identified, then this land area is called an ecosystem. It’s just that a biocenosis has many similarities with an ecosystem, so they are often used as synonyms.
- Secondly, the concept of “ecosystem” is much broader and more widespread than “biogeocenosis”.
- Thirdly, in the ecosystem there is a diversity of ranks, which is not the case in biogeocenosis.
- Fourthly, the biocenosis is distinguished only on land, but the ecosystem can be distinguished everywhere.
The line between an ecosystem and a biogeocenosis is very subtle, but it exists!
The term “biogeocenosis” is often used in both ecology and biology. This is a set of objects of biological and non-biological origin, limited to a certain territory and characterized by the mutual exchange of substances and energy.
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Definition
When they remember which scientist introduced the concept of biogeocenoses into science, they talk about the Soviet academician V.N. Sukachev. The term biogeocenosis was proposed by him in 1940. The author of the doctrine of biogeocenosis not only proposed the term, but also created a coherent and detailed theory about these communities.
In Western science, the definition of “biogeocenosis” is not very common. The doctrine of ecosystems is more popular there. Sometimes ecosystems are called biocenosis, but this is incorrect.
There are differences between the concepts of “biogeocenosis” and “ecosystem”. Ecosystem is a broader concept. It can be limited to a drop of water, or it can spread over thousands of hectares. The boundaries of a biogeocenosis are usually the area of a single plant complex. An example of a biogeocenosis could be a deciduous forest or a pond.
Properties
The main components of biogeocenosis of inorganic origin are air, water, minerals and other elements. Living organisms include plants, animals and microorganisms. Some live in the terrestrial world, others underground or underwater. True, from the point of view of the functions they perform, the characteristics of biogeocenosis look different. The biogeocenosis includes:
- producers;
- consumers;
- decomposers.
These main components of biogeocenosis are involved in metabolic processes. There is a close connection between them.
The role of producers of organic substances in biogeocenoses is played by producers. They convert solar energy and minerals into organic matter, which serves as a building material for them. The main process organizing biogeocenosis is photosynthesis. We are talking about plants that convert solar energy and soil nutrients into organic matter.
After death, even a formidable predator becomes prey for fungi and bacteria that decompose the body, turning organic substances into inorganics. These participants in the process are called decomposers. Thus, a circle consisting of interconnected species of plants and animals is closed.
Briefly, the biogeocenosis diagram looks like this. Plants consume energy from the sun. These are the main producers of glucose in the biogeocenosis. Animals and other consumers transfer and transform energy and organic matter. Biogeocenosis also includes bacteria that mineralize organic matter and help plants absorb nitrogen. Every chemical element present on the planet, the entire periodic table, participates in this cycle. Biogeocenosis is characterized by a complex, self-regulating structure. And everyone who participates in its processes is important and necessary.
The mechanism of self-regulation, which is also called dynamic balance, will be explained with an example. Let's say favorable weather conditions lead to an increase in the amount of plant food. This largely caused the growth of the herbivore population. Predators began to actively hunt them, reducing the number of herbivores, but increasing their population. There is not enough food for everyone, so some of the predators have died out. As a result, the system returned to a state of equilibrium again.
Here are the signs that indicate the stability of biogeocenoses:
- a large number of species of living organisms;
- their participation in the synthesis of inorganic substances;
- wide living space;
- absence of negative anthropogenic impact;
- a wide range of types of interspecific interaction.
Kinds
Natural biogeocenosis is of natural origin. Examples of artificial biogeocenoses are city parks or agrobiocenoses. In the second case, the main process organizing the biogeocenosis is human agricultural activity. The state of the system is determined by a number of anthropogenic characteristics.
The main properties of biogeocenoses created by man in the agricultural sector depend on what the field is sown with, how successful the control of weeds and pests is, what fertilizers and in what quantity are applied, and how often watering is done.
If the treated crops are suddenly abandoned, without human intervention they will die, and weeds and pests will begin to actively multiply. Then the properties of the biogeocenosis will become different.
Artificial biogeocenosis created by man is not capable of self-regulation. The stability of biogeocenosis depends on the person. Its existence is possible only with active human intervention. The abiotic component of biogeocenosis is often also included in its composition. An example would be an aquarium. In this small artificial reservoir, various organisms live and develop, each of which is part of the biogeocenosis.
Most natural communities are formed over a long period of time, sometimes hundreds and thousands of years. The participants spend a long time getting used to each other. Such biogeocenoses are characterized by high stability. Equilibrium rests on the interconnection of populations. The stability of biogeocenosis is determined by the relationships between the participants in the process and is stable. If there are no significant natural and man-made disasters associated with destruction or gross human intervention, the biogeocenosis, as a rule, is constantly in a state of dynamic equilibrium.
Each type of relationship is an important limiting factor in maintaining balance in the system.
Examples
Let's consider what biogeocenosis is, taking a meadow as an example. Since the primary link in the food webs of biogeocenoses is producers, meadow grasses play this role here. The initial source of energy in the biogeocenosis of the meadow is the energy of the Sun. Herbs and shrubs, these main producers of glucose in the biogeocenosis, grow and serve as food for animals, birds and insects, which, in turn, become prey for predators. Dead remains fall into the soil and are processed by microorganisms.
A feature of the phytocenosis (plant world) of deciduous forests, in contrast to meadows or steppes, is the presence of several tiers. The inhabitants of the upper tiers, which include taller trees, have the opportunity to consume more solar energy than those of the lower ones, which are able to exist in the shade. Then there is a layer of shrubs, then grasses, then, under a layer of dry leaves and near tree trunks, mushrooms grow.
Biogeocenosis has a wide variety of plant species and other living organisms. Animal habitats are also divided into several tiers. Some live in the treetops, while others are underground.
Such a biogeocenosis as a pond is characterized by the fact that the habitat is water, the bottom of the reservoir and the surface surface. Here the flora is represented by algae. Some of them float on the surface, and some are constantly hidden under water. They feed on fish, insects, and crustaceans. Predatory fish and insects easily find prey, and bacteria and other microorganisms live at the bottom of the reservoir and in the water column.
Despite the relative stability of natural biogeocenoses, over time the properties of the biogeocenosis change, turning from one to another. Sometimes a biological system reorganizes quickly, as in the case of overgrowing of small bodies of water. They can turn into swamps or meadows in a short time.
The formation of a biogeocenosis can last for centuries. For example, rocky, almost bare rocks are gradually covered with mosses, then other vegetation appears, destroying the rock and changing the landscape and fauna. The properties of biogeocenosis are changing slowly but steadily. Only people are able to dramatically accelerate these changes and not always for the better.
A person must treat nature with care, preserve its riches, and prevent environmental pollution and barbaric treatment of its inhabitants. He must not forget that this is his home, where his descendants will have to live. And it depends only on him in what condition they will receive it. Understand this yourself and explain it to others.
Biocenosis(or community) is a historically established stable set of populations of organisms of different species inhabiting a relatively homogeneous area of territory or water area and connected by certain relationships. (K. Mobius, 1877).
Examples of biocenoses: communities on a tree trunk, in a hole, in a section of forest, meadow, lake, swamp, pond, etc.
Different populations of the biocenosis must be adapted to living together. It means that:
■ all types of biocenosis must have similar requirements for abiotic environmental conditions (light, temperature, humidity, etc.);
■ there must be regular trophic (food), topical, phoric and factory relationships between organisms of different populations, necessary for their nutrition, reproduction, settlement and protection.
❖ Components of the biocenosis:
■ phytocenosis
(sustainable plant community); has easily recognizable characteristic features and boundaries, is the main structural component of any biocenosis, determines the species composition of zoo-, myco- and microcoenoses;
■ zoocenosis
(a set of interrelated animal species);
■ mycocenosis
(fungal community);
■ microbiocenosis
(community of microorganisms).
Ecotop- This primary a complex of abiotic environmental factors and some components of living origin (soil, ground) present on the area of the earth's surface (land or body of water) occupied by one or another biocenosis, without taking into account the changes introduced by living beings of this biocenosis.
■ All ecotope factors can be divided into climatetop
, edaphotope
And hydrotope
.
Climatope
- a set of climatic factors of the ecotope.
Edaphotope
— a set of soil and ground factors.
Hydrotope
— a set of hydrofactors (the presence and characteristics of a reservoir, the water it contains, etc.).
Biotope- this is a section of the environment (land or body of water) that has relatively homogeneous living conditions and is occupied by one biocenosis. In this case, environmental conditions are considered taking into account all the modifications that were introduced into them by the organisms of a given biocenosis.
Biogeocenosis and ecosystem
Biogeocenosis(briefly - BGC) is a single natural complex lying within the boundaries of a certain phytocenosis and connected by the mutual exchange of substances and energy, formed by a section of the earth's surface (land) with certain environmental conditions (biotope) and populations of all types of organisms inhabiting this biotope (biocenosis), see Fig. .
Examples of biogeocenoses: spruce forest, oak forest, sphagnum bog, dry meadow, etc.
Biogeocenosis functions as an integral, self-reproducing, self-regulating open system. Populations of organisms receive from the inorganic environment the resources necessary to support life, and at the same time release waste products that restore the environment.
Ecological system(or ecosystem) - any set of co-living organisms and inorganic components, during the interaction of which occurs circulation of substances and energy flow .
Examples of ecosystems; a rotting stump, an anthill, a puddle of rainwater, a park, an aquarium, a biosphere, etc.
The difference between an ecosystem and a biogeocenosis. The concept of an ecosystem does not require any restrictions on the territory or water area it occupies and can be applied to any complex of organisms and their habitats (including aquatic ones), not only natural ones, but also those created by man. Biogeocenosis is a natural ecosystem isolated on land, the boundaries of which are determined by phytocenosis, i.e. plant community. Therefore, an ecosystem is a broader concept than a biogeocenosis: any biogeocenosis is an ecosystem, but not every ecosystem is a biogeocenosis .
❖ Components of biogeocenosis:
■ inorganic substances included in the cycle (carbon and nitrogen compounds, oxygen, water, mineral salts);
■ climatic factors (temperature, light, humidity);
■ organic substances (proteins, nucleic acids, carbohydrates, lipids, etc.);
■ organisms of various functional groups - producers, consumers, decomposers.
Producers- autotrophic organisms (mainly green plants and algae) that synthesize organic substances from inorganic ones. Producers use the energy of the Sun, converting it into chemical energy of organic substances, available to all other organisms.
Decomposers- heterotrophic organisms (bacteria, fungi), which, in the process of their feeding, destroy the organic matter of dead plants and animals and animal excrement, transforming them into simple inorganic compounds suitable for assimilation by plants.
Characteristics biogeocenosis (ecosystems): biomass, productivity, species diversity, population density of each species, the ratio of species in terms of numbers and population density, spatial and trophic (food) structure, etc.
Biomass— the total mass of all organisms of an ecosystem or its individual trophic levels.
■ Biomass is usually expressed in units of mass of matter per unit area or volume of an ecosystem (kg/ha, kg/m3, etc.).
■ The biomass of all organisms on Earth is 2.4 10 12 tons of dry matter, 90% of this amount is the biomass of terrestrial plants.
Productivity- the increase in biomass created by ecosystem organisms per unit of time per unit area or volume.
■ Productivity is expressed in units of mass of a substance per unit area or volume over a certain period of time (kg/m2 per year, etc.).
Primary productivity of an ecosystem- the amount of biomass produced per unit of time by all plants of this ecosystem as a result of photosynthesis.
Secondary ecosystem productivity- the amount of biomass produced by all consumers of this ecosystem per unit of time.
■ The total annual production of dry organic matter on Earth is 150-200 billion tons (2/3 of which comes from terrestrial ecosystems, 1/3 from aquatic ecosystems).
■ The most productive ecosystems: tropical rain forest (about 2 kg/m2 per year) and subpolar regions of the World Ocean (about 0.25 kg/m2 per year).
Species structure of biogeocenosis (ecosystem)
Species structure of BGC or ecosystems - the diversity of species of all populations included in the BGC (or ecosystem) and the ratio of these species in numbers (or biomass) and population density.
■ In each ecosystem there is a natural selection of organisms that are most adapted to given environmental conditions.
■ There are ecosystems rich in species (coral reefs, tropical rainforests, etc.) and species poor (Arctic tundra, deserts, swamps, etc.).
Dominant species- species that predominate in number of individuals or occupy a large area in a given ecosystem.
Edifier species- dominant species (usually plants, sometimes animals), playing a major role in determining the composition, structure and properties of the ecosystem by creating an environment for the entire community (in a spruce forest - spruce, in a birch forest - birch, etc.).
■ For example, in a spruce forest the illumination is much less, and the air temperature is lower than in a deciduous forest; rainwater flowing from the crowns of spruce trees has an acidic reaction, and a thick litter of very slowly decomposing pine needles with a low humus content is formed under the trees. As a result, spruce, in the course of its life activity, changes environmental conditions so much that this biotope becomes unsuitable for the existence of many species of organisms and is populated only by species that are well adapted to life in such conditions.
The role of rare and small species: they increase the diversity of connections in the community and serve as a reserve for replacing dominant species.
■The more specific the environmental conditions, the poorer the species composition and the higher the number of individual species. Conversely, in rich communities all species are scarce.
■ The higher the species diversity, the more resilient the community.
Spatial and ecological structures of biogeocenosis
Spatial structure— distribution of organisms (mainly plants) across fairly clearly limited spatial (vertical and/or horizontal) structural elements — tiers and microgroups .
tiers characterize vertical dismemberment of phytocenoses. They are formed by above-ground vegetative organs of plants and their root systems.
■ The main factor determining the vertical distribution of plants is the amount of light, which determines temperature and humidity regimes at different levels above the soil surface in the biogeocenosis. The upper tiers are formed by light-loving plants that are better adapted to fluctuations in temperature and air humidity; the lower tiers are inhabited by plants that are less demanding of light.
■ Tiers are well defined in the forest (woody, shrubby, herbaceous, mossy, etc.). Animals are also distributed among tiers (inhabitants of shrubs, moss, soil, etc.).
■ The underground layering of phytocenoses is weakly expressed or absent. As a rule, the total mass of underground organs naturally decreases from top to bottom.
Mosaic— horizontal dissection (heterogeneity) of the biogeocenosis, expressed in the presence of various microgroups in it, which differ in species composition, quantitative ratio of different species, productivity and other characteristics and properties.
The mosaic is due to:
■ heterogeneity of microrelief;
■ features of the biology of reproduction and plant form;
■ by the activities of plants, animals and humans (formation of anthills, trampling of grass, selective cutting of trees, etc.).
The ecological structure of the BGC is the relationship between the various ecological groups of organisms that make up a given biogeocenosis.
■ The diversity and abundance of representatives of a particular ecological group depend on environmental conditions (in deserts, xerophytic plants and animal xerophiles, adapted to life in conditions of lack of water, predominate; in aquatic communities, hydrophytic plants and hydrophilic animals, etc.) prevail and develop over the course of for a long time in certain climatic, soil and landscape conditions is strictly natural.
■ This diversity ensures a high density of organisms per unit area, their maximum biological productivity and optimal competitive relationships.
Communities with a similar ecological structure may have different species composition, since the same ecological niches can be occupied by different species (example: the same ecological niche is occupied by marten in the European taiga, and sable in the Siberian taiga).
Trophic structure of the ecosystem. Cycle of substances and energy flow in ecosystems
All organisms in any ecosystem share a commonality of nutrients and energy necessary to sustain life. A necessary condition for the existence of an ecosystem is a constant flow of energy from outside. The main way of movement of substances and energy in an ecosystem is nutrition.
Trophic level- a set of organisms united by a type of nutrition.
The following trophic levels are distinguished:
■ first level form autotrophic organisms ( producers ), creating organic substances from inorganic ones using solar energy;
■ second trophic level form herbivores animals ( 1st order consumers: caterpillars of butterflies, mice, voles, hares, goats, etc.) consuming organic substances created by producer plants;
■third trophic level make up carnivores animals ( 2nd order consumers: predatory insects, insectivorous birds, etc.) eating small herbivores;
■ fourth trophic level form carnivores animals ( 3rd order consumers : birds of prey and animals), consuming consumers of the 2nd order, etc.
Carnivores can move from the third to the fourth level and back, as well as to higher trophic levels.
Trophic (food) chain(or power circuit) - a number of organisms connected to each other by food relationships (by eating some species by others) and constituting a certain sequence according to which the circulation of substances and the flow of energy in the ecosystem occurs by transferring them from one trophic level to another.
■ Individual links in the trophic chain are organisms belonging to different trophic levels.
Trophic network of an ecosystem- a complex connection of all food chains characteristic of a given ecosystem, in which the links of one chain are components of other chains.
■ The trophic network reflects trophic structure ecosystems.
❖ Types of trophic chains:
■pasture chains(grazing chains or consumption ) begin with photosynthetic producing organisms: on the land : plants → insects → insectivorous birds → birds of prey; or plants → herbivorous mammals → carnivorous mammals; in the sea : algae and phytoplankton → lower crustaceans (zooplankton) → fish → mammals (and partly birds). Pasture chains predominate in seas at relatively shallow depths.
■ detrital chains(chains decomposition) begin with dead small remains of plants, corpses and animal excrement ( detritus): detritus → decomposer microorganisms feeding on it (bacteria, fungi) → small animals (detritivores: earthworms, woodlice, mites, springtails, nematodes) → predators (birds, mammals). Such chains are most common in forests, where more than 90% of the annual increase in plant biomass dies, undergoing decomposition by saprotrophic organisms and mineralization.
❖ Basic characteristics of the food chain within the biogeocenosis: chain length, number, size and biomass of organisms at each trophic level.
■ The food chain usually consists of 3-5 links (trophic levels) due to large energy losses for the construction of new tissues and respiration of organisms.
The productivity of organisms at each subsequent trophic level of the food chain is always less (on average 10 times) than the production of the previous one, because:
■ only part of the food is assimilated by consumers (the rest is excreted in the form of excrement);
■ most of the nutrients absorbed by the intestines are spent on respiration and other vital processes.
Ecological pyramid- a graphic representation of the relationship between the numbers of individuals, biomass or energies of organisms that make up the trophic levels in an ecosystem, expressed in the number of individuals.
■ In this case, individual links of the food chain are depicted in the form of rectangles, the area of which corresponds to the numerical values of the links.
Types of ecological pyramids:
■ the pyramid of numbers graphically displays the ratio of the numbers of individuals of different trophic levels of the ecosystem;
■ the biomass pyramid graphically shows the amount of biomass (mass of living matter) at each trophic level;
■ The energy pyramid graphically displays the magnitude of energy flows transferred from one trophic level to another.
❖ Properties of ecological pyramids:
■ the height of the pyramids is determined by the length of the food chain;
■ the biomass and number of individuals of each subsequent link in the food chain progressively decreases - the rule of the ecological pyramid; it operates in most (but not all) terrestrial ecosystems; in such ecosystems, the bases of the pyramids of numbers and biomass are larger than subsequent levels;
■ in aquatic ecosystems, the bases of pyramids of numbers and biomass may be smaller than the sizes of subsequent levels (the pyramids are inverted), which is explained by the small size of producer organisms (unicellular algae - phytoplankton);
■ the pyramid of energy in terrestrial and aquatic ecosystems always narrows upward, since the energy spent on respiration is not transferred to the next trophic level and leaves the ecosystem.
Self-reproduction. self-regulation and sustainability of ecosystems
Any ecosystem is a complex dynamic system consisting of many hundreds, sometimes thousands of species of organisms, united by trophic, topical and other connections.
Self-reproduction— the ability of ecosystems to recreate the flow of energy and ensure the circulation of basic substances and elements between living and nonliving components.
■ Living organisms extract resources from the environment and supply waste products to it (plants use light energy, CO 2, H 2 O, replenish the atmosphere with O 2; animals absorb O 2 from the atmosphere, release CO 2 into it, etc.).
Self-regulation- the ability of the population of an ecosystem to restore its species and quantitative composition after any deviation, as well as the ability of its various species to exist together without completely destroying each other, but only limiting the number of individuals of each species to a certain level.
■ Regulatory factors are formed in the ecosystem itself: predators regulate the number of their prey, the activities of herbivores affect plants, etc.
Ecosystem homeostasis- the property of the relative constancy of the species composition and number of individuals of various species in an ecosystem, as well as the relative stability and integrity of the genetic structure of the ecosystem.
■ The specified constancy is observed only on average and reflects the dynamic balance of opposing factors.
Sustainability— the ability of an ecosystem to withstand changes caused by external (natural or anthropogenic) influences, and to restore connections and dynamic balance between its main components that are disrupted by external influences.
■ The sustainability of each ecosystem has its own limits: if the intensity or duration of external influence exceeds a certain threshold, the ecosystem may die.
♦ Factors ensuring the stability and longevity of the ecosystem:
■ constant influx of solar energy;
■ the general circulation of substances carried out by producers, consumers and decomposers;
■ self-regulation of the ecosystem;
■ biological diversity and complexity of trophic relationships of the organisms included in its composition;
■ the ability for organisms to switch to feeding on another species instead of a species that has become rare (since almost all animal species can use several food sources); at the same time, a small species, freed from the pressure of grazing, will gradually restore its numbers;
■ high reproduction potential of the main groups of organisms in the ecosystem (an ecosystem is stable if a decrease in precipitation by 50% leads to a decrease in the mass of producers by 25%, herbivorous consumers by 12.5%, predatory consumers by 6.2%, etc.);
■ genetic diversity of individuals in populations; the higher it is, the greater the chance for a population to have organisms with alleles responsible for the appearance of traits and properties that allow them to survive and reproduce in changed conditions of existence and restore their previous numbers;
■ low degree of fluctuations in environmental conditions. For example, tropical ecosystems are highly stable, since the tropics are characterized by relative constancy of temperature, humidity, and light. On the contrary, the tundra is characterized by sharp changes in temperature, humidity, and illumination, therefore tundra ecosystems are less stable and are characterized by sharp fluctuations in the numbers of populations of different species.
Based on knowledge of the laws of ecosystem dynamics, calculations of their productivity and energy flows make it possible to regulate the size of populations and the circulation of substances in ecosystems so as to achieve the greatest yield of products necessary for humans.
Ill-considered human intervention in ecosystems can disrupt natural food chains and lead to uncontrolled growth or decline in the number of individuals in certain populations and disruption of natural ecosystems.
Self-development and succession of ecosystems
An absolutely stable state of the ecosystem is never achieved due to:
■ variability of environmental conditions;
■ changes occurring in the ecosystem itself as a result of the life activity of its organisms.
Self-development of the ecosystem- its ability to undergo cyclical and progressive changes caused by various reasons.
■ Cyclic changes are usually associated with daily and seasonal changes in external conditions and biological rhythms of organisms.
■ Progressive changes are caused by constantly acting external or internal factors and lead to the replacement of one biogeocenosis by another (succession).
succession- a natural, consistent, irreversible and directional change (in a certain territory) of one biogeocenosis to another.
The replacement of one phytocenosis in an ecosystem by another is successional series. In the absence of disturbances, succession ends with the formation of a more stable community that is in relative balance with the abiotic environment (spruce forest, oak forest, feather grass steppes, peat bog, etc.).
❖ Reasons for succession:
■external: constantly operating external factors: changes in climate and soil conditions in a given territory (swamping, salinization), including as a result of human economic activity (deforestation, irrigation of land in dry areas, drainage of swamps, application of fertilizers to meadows, plowing, increased grazing, etc.);
■ internal: changes that occur in a biotope as a result of the vital activity of organisms during the long-term existence of populations in one place, due to which the biotope becomes unsuitable for some species, but suitable for others. As a result, a different biocenosis, more adapted to new conditions, develops in this place.
A change in the conditions of the habitat (biotope) inevitably leads to a change (change) in the biocenosis. As a result, a new one arises in place of the previous biogeocenosis (ecosystem). The leading role in the process of changing biogeocenoses belongs to plants, although biogeocenoses change as a single whole. Simultaneously with the change in vegetation, the animal world also changes.
❖ Classification of successions depending on the state and properties of the environment:
■ primary, starting in areas devoid of soil and vegetation (on bare rocks, sand dunes, formed reservoirs, river sediments, frozen lava flows, etc.; they last hundreds and thousands of years. The most important stage of such successions is the formation of soil through the accumulation of dead plant matter residues or products of their decomposition;
■ secondary, occurring on the site of established communities after their disruption as a result of erosion, fire, deforestation, drought, volcanic eruption, etc. Since such places usually retain rich life resources, these successions occur quickly (over tens of years).
Agroienosis
Agrocenosis(or agrobiocenosis) is an ecosystem artificially created by man, the structure and functions of which he maintains and controls in his own interests. This is a community of organisms living on agricultural lands occupied by crops or plantings of cultivated plants.
Examples; fields, vegetable gardens, orchards, parks, forest plantations, pastures, greenhouses, aquariums, fish ponds, etc.
The role of humans in agrocenosis: he creates an agrocenosis, ensures its high productivity using a set of special agrotechnical techniques, collects and uses the crop.
❖ The role of agrocenoses:
■ currently they occupy 10% of the total land surface (about 1.2 billion hectares) and annually produce 2.5 billion tons of agricultural products (about 90% of all food energy needed by humanity);
■ they have enormous potential for increasing productivity, the implementation of which is possible with constant, scientifically based soil care, provision of plants with moisture and mineral nutrients, and protection of plants from unfavorable abiotic and biotic factors.
IN composition of agrocenosis includes cultivated plants, weeds, insects, earthworms, mouse-like rodents, birds, bacteria, fungi and other organisms interconnected by trophic relationships.
Food chains in agrocenosis the same as in the natural ecosystem: producers (cultivated plants and weeds), consumers (insects, birds, voles, foxes) and decomposers (bacteria, fungi); An essential link in the food chain is humans.
❖ Differences between agrocenoses and natural biogeocenoses:
■ in agrocenoses it is not natural that acts predominantly, but artificial selection , which is aimed by man mainly at maximizing the productivity of agricultural crops. This sharply reduces the ecological stability of agrocenoses, which are not capable of self-regulation and self-renewal, cannot exist independently (without human support) for a more or less long time (they turn into a biogeocenosis) and can die due to the mass reproduction of pests or pathogens;
■ in agrocenoses there is no complete cycle of substances and the balance of nutrients is sharply disturbed (most of them are removed by humans during harvesting); To compensate for losses, it is necessary to constantly add various nutrients to the soil in the form of fertilizers;
■ agrocenoses, in addition to solar energy, have an additional source of energy in the form of energy mineral and organic fertilizers introduced by humans, chemical means of protection against weeds, pests and diseases, energy spent on soil cultivation, irrigation or drainage of land, etc.;
■ change of agrocenoses occurs at the will of man (in field agrocenoses - crop rotation );
■the productivity of agrocenoses is higher than biogeocenoses.
♦ Methods for increasing the productivity of agrocenoses:
■ soil drainage and irrigation;
■ combating erosion (strengthening slopes, moldboard-free plowing, grassing former peatlands);
■ standardized application of fertilizers;
■ dosed application of means to combat weeds, pests and plant diseases;
■ use of biological methods of pest control;
■ use of high-performance equipment;
■ development and use of new high-yielding varieties of cultivated plants that are resistant to diseases and pests;
■ compliance with scientifically based crop rotations;
■ use of greenhouses and greenhouses;
■ the use of methods for growing vegetables without soil - hydroponics (gravel irrigated with salt solutions is used as a substrate) and aeroponics (there is no substrate, and the roots are periodically sprayed with solutions of mineral salts). 
The concept of biogeocenosis first appeared in the works of the Soviet biologist V. Sukachev in 1942. This term today means a system located in a certain part of space and including all living organisms living in this area, and a set of inanimate factors that influence their existence. Parts of living and inanimate nature are connected by a constant cycle of energy metabolism and metabolism, due to which the system gains the ability to self-regulate.
One of the main distinguishing features of the current biogeocenosis is its homogeneity in species of living beings and the abiotic factors present. The energy component, as a rule, relies on receiving, its absorption and transformation.
Components of biogeocenosis
The decisive role in the existence of biogeocenosis belongs to living organisms, which in biology are divided into three main types:
— producers- living organisms that consume nutrients for their vital functions directly from inanimate nature. These include most plant species and some bacterial species;
With the help of these three components, the cycle of nutrients and energy of the biogeocenosis is carried out. Producers absorb inorganic substances from the soil and solar energy, thanks to which they are able to build their cells and increase the volume of organic substances. Consumers actively eat producers and each other, including the organic substances they produce in their biochemical and energy metabolism. The function of decomposers is to decompose organic matter remaining after the death of living organisms and thereby return nutrient minerals back to the soil.
Structure of biogeocenoses
Different biogeocenoses are formed under different conditions in terms of the degree of daylight, climatic conditions, soil composition, etc. It is not surprising that their species composition, the amount of biomass and the number of interspecific connections are completely different in different ecosystems. Scientists consider the spatial, species, trophic and ecological structure of biogeocenosis. 
Species structure- this is the diversity of species included in the biogeocenosis, and the ratio of the biomass or number of all its constituent populations. Biogeocenoses can be rich in species composition if the conditions of the biotope are favorable for most species of living beings, or poor - living in not very favorable conditions (in deserts, tundra, etc.).
Spatial structure is determined primarily by the plant components of the biogeocenosis, which are most often structured vertically. Each of the plant layers has its own composition of plant and animal inhabitants, as well as insects and microorganisms.
Ecological structure biogeocenosis is a set of ecological groups of living beings, the ratio of which varies depending on the prevailing abiotic factors.
Trophic structure- this is the number and composition of food chains formed by the totality of species of living beings living in a biogeocenosis. 
As a rule, biogeocenosis develops over many hundreds and sometimes thousands of years. From time to time, new components are introduced into its composition, which either take their place in its structures or are gradually removed thanks to the existing system of self-regulation.
The concept of “ecosystem” was introduced in 1935 by A. Tansley, an English botanist. With this term he designated any collection of organisms living together, as well as their environment. Its definition emphasizes the presence of interdependence, relationships, cause-and-effect relationships that exist between the abiotic environment and the biological community, combining them into a certain functional whole. An ecosystem, according to biologists, is a collection of all kinds of populations of various species that live in a common territory, as well as the inanimate environment that surrounds them.
Biogeocenosis is a natural formation that has clear boundaries. It consists of a set of biocenoses (living beings) that occupy a certain place. For example, for aquatic organisms this place is water, for those living on land it is the atmosphere and soil. Below we will look at which will help you understand what it is. We will describe these systems in detail. You will learn about their structure, what types they exist and how they change.
Biogeocenosis and ecosystem: differences
To some extent, the concepts of “ecosystem” and “biogeocenosis” are unambiguous. However, they do not always coincide in volume. Biogeocenosis and ecosystem are related as a less broad and broader concept. An ecosystem is not connected to a certain limited area of the earth's surface. This concept can be applied to all stable systems of nonliving and living components in which internal and external circulation of energy and substances occurs. Ecosystems, for example, include a drop of water with microorganisms in it, a flower pot, an aquarium, a biofilter, an aeration tank, and a spaceship. But they cannot be called biogeocenoses. An ecosystem may also contain several biogeocenoses. Let's look at some examples. It is possible to distinguish biogeocenoses of the ocean and biosphere as a whole, continent, belt, soil-climatic region, zone, province, district. Thus, not every ecosystem can be considered a biogeocenosis. We found this out by looking at examples. But any biogeocenosis can be called an ecological system. We hope you now understand the specifics of these concepts. “Biogeocenosis” and “ecosystem” are often used as synonyms, but there is still a difference between them.
Features of biogeocenosis
Many species usually live in any of the limited spaces. A complex and permanent relationship is established between them. In other words, different types of organisms that exist in a certain space, characterized by a set of special physical and chemical conditions, represent a complex system that persists for a more or less long time in nature. Clarifying the definition, we note that a biogeocenosis is a community of organisms of various species (historically established), which are closely related to each other and to their surroundings, the exchange of energy and substances. A specific characteristic of a biogeocenosis is that it is spatially limited and quite homogeneous in the species composition of the living creatures included in it, as well as in the complex of various Existence as an integral system ensures a constant supply of solar energy to this complex. As a rule, the boundary of a biogeocenosis is established along the boundary of a phytocenosis (plant community), which is its most important component. These are its main features. The role of biogeocenosis is great. At its level, all processes of energy flow and circulation of substances in the biosphere occur.
Three groups of biocenosis
The main role in the interaction between its various components belongs to the biocenosis, that is, living beings. They are divided according to their functions into 3 groups - decomposers, consumers and producers - and closely interact with the biotope (inanimate nature) and with each other. These living beings are united by the food connections that exist between them.
Producers are a group of autotrophic living organisms. By consuming the energy of sunlight and minerals from the biotope, they thereby create primary organic substances. This group includes some bacteria, as well as plants.
Decomposers decompose the remains of dead organisms, and also break down organic substances into inorganic substances, thereby returning mineral substances “removed” by producers to the biotope. These are, for example, some types of unicellular fungi and bacteria.
Dynamic equilibrium of the system
Types of biogeocenosis
Biogeocenosis can be natural and artificial. The types of the latter include agrobiocenoses and urban biogeocenoses. Let's take a closer look at each of them.
Natural biogeocenosis
Let us note that every natural biogeocenosis is a system that has developed over a long period of time - thousands and millions of years. Therefore, all its elements are “ground in” to each other. This leads to the fact that the resistance of the biogeocenosis to various changes occurring in the environment is very high. The "strength" of ecosystems is not unlimited. Profound and abrupt changes in living conditions, a reduction in the number of species of organisms (for example, as a result of large-scale fishing of commercial species) lead to the fact that the balance can be disturbed and it can be destroyed. In this case, a change in biogeocenoses occurs.
Agrobiocenoses
Agrobiocenoses are special communities of organisms that develop in areas used by people for agricultural purposes (plantings, crops of cultivated plants). Producers (plants), in contrast to natural biogeocenoses, are represented here by one type of crop grown by humans, as well as a certain number of weed species. Diversity (rodents, birds, insects, etc.) determines the vegetation cover. These are species that can feed on plants growing on the territory of agrobiocenoses, as well as be in conditions of their cultivation. These conditions determine the presence of other species of animals, plants, microorganisms and fungi.
Agrobiocenosis depends, first of all, on human activities (fertilization, mechanical tillage, irrigation, treatment with pesticides, etc.). The stability of the biogeocenosis of this species is weak - it will collapse very quickly without human intervention. This is partly due to the fact that cultivated plants are much more demanding than wild ones. Therefore, they cannot compete with them.
Urban biogeocenoses
Urban biogeocenoses are of particular interest. This is another type of anthropogenic ecosystem. An example is parks. The main ones, as in the case of agrobiocenoses, are anthropogenic. The species composition of plants is determined by humans. He plants them and also cares for and processes them. Changes in the external environment are most pronounced in cities - an increase in temperature (from 2 to 7 ° C), specific features of soil and atmospheric composition, a special regime of humidity, light, and wind action. All these factors form urban biogeocenoses. These are very interesting and specific systems.
Examples of biogeocenosis are numerous. Different systems differ from each other in the species composition of organisms, as well as in the properties of the environment in which they live. Examples of biogeocenosis, which we will dwell on in detail, are a deciduous forest and a pond.
Deciduous forest as an example of biogeocenosis
Deciduous forest is a complex ecological system. The biogeocenosis in our example includes plant species such as oaks, beeches, lindens, hornbeams, birches, maples, rowan trees, aspens and other trees whose leaves fall in the fall. Several of their tiers stand out in the forest: low and high trees, moss ground cover, grasses, shrubs. Plants inhabiting the upper tiers are more light-loving. They withstand fluctuations in humidity and temperature better than representatives of the lower tiers. Mosses, grasses and shrubs are shade-tolerant. They exist in the summer in the twilight formed after the leaves of the trees unfold. The litter lies on the surface of the soil. It is formed from semi-decomposed remains, twigs of bushes and trees, fallen leaves, and dead grass.
Forest biogeocenoses, including deciduous forests, are characterized by a rich fauna. They are inhabited by many burrowing rodents, predators (bear, badger, fox), and burrowing insectivores. There are also tree-dwelling mammals (chipmunk, squirrel, lynx). Roe deer, moose, and deer are part of the group of large herbivores. Boars are widespread. Birds nest in different layers of the forest: on trunks, in bushes, on the ground or on the tops of trees and in hollows. There are many insects that feed on leaves (for example, caterpillars), as well as wood (bark beetles). In addition to insects, the upper layers of the soil, as well as the litter, contain a huge number of other vertebrates (ticks, earthworms, insect larvae), many bacteria and fungi.
Pond as a biogeocenosis
Let's now consider a pond. This is an example of a biogeocenosis, in which the living environment of organisms is water. Large floating or rooting plants (pondweed, water lilies, reeds) settle in the shallow waters of ponds. Small floating plants are distributed throughout the water column, to the depth where light penetrates. These are mainly algae called phytoplankton. Sometimes there are a lot of them, as a result of which the water turns green and “blooms.” A variety of blue-green, green and diatom algae are found in phytoplankton. Tadpoles, insect larvae, and crustaceans feed on plant debris or living plants. Fish and predatory insects eat small animals. And herbivorous and smaller predatory fish are hunted by large predatory fish. Organisms that decompose organic matter (fungi, flagella, bacteria) are widespread throughout the pond. There are especially many of them at the bottom, since the remains of dead animals and plants accumulate here.
Comparison of two examples
Having compared examples of biogeocenosis, we see how different the ecosystems of a pond and a forest are in both species composition and appearance. This is due to the fact that the organisms inhabiting them have different habitats. In a pond it is water and air, in a forest it is soil and air. Nevertheless, the functional groups of organisms are of the same type. In the forest, producers are mosses, grasses, shrubs, and trees; There are algae and floating plants in the pond. In the forest, consumers include insects, birds, animals and other invertebrates that inhabit the litter and soil. Consumers in the pond include various amphibians, insects, crustaceans, predatory and herbivorous fish. In the forest, decomposers (bacteria and fungi) are represented by terrestrial forms, and in a pond - by aquatic ones. Let us also note that both the pond and the deciduous forest are a natural biogeocenosis. We gave examples of artificial ones above.
Why do biogeocenoses replace each other?
Biogeocenosis cannot exist forever. It will inevitably sooner or later be replaced by another. This occurs as a result of changes in the environment by living organisms, under the influence of humans, in the process of evolution, and with changing climatic conditions.
An example of a change in biogeocenosis
Let us consider, as an example, the case when living organisms themselves cause a change in ecosystems. This is the colonization of rocks with vegetation. Weathering of rocks is of great importance in the first stages of this process: partial dissolution of minerals and changes in their chemical properties, destruction. At the initial stages, the first settlers play a very important role: algae, bacteria, blue-greens. The producers are free-living algae and lichens. They create organic matter. Blue-greens take nitrogen from the air and enrich it with it in an environment that is still unsuitable for habitation. Lichens dissolve rock with secretions of organic acids. They contribute to the gradual accumulation of mineral nutrition elements. Fungi and bacteria destroy organic substances created by producers. The latter are not completely mineralized. A mixture consisting of mineral and organic compounds and nitrogen-enriched plant residues gradually accumulates. Conditions are created for the existence of bushy lichens and mosses. The process of accumulation of nitrogen and organic matter accelerates, and a thin layer of soil is formed.
A primitive community is formed that can exist in this unfavorable environment. The first settlers were well adapted to the harsh conditions of the rocks - they withstood frost, heat, and dryness. Gradually they change their habitat, creating conditions for the formation of new populations. After herbaceous plants (clover, grasses, sedges, bellflowers, etc.) appear, competition for nutrients, light, and water becomes more intense. In this struggle, the pioneer settlers are replaced by new species. Shrubs settle behind herbs. They hold the emerging soil together with their roots. Forest communities are replaced by grass and shrub communities.
During the long process of development and change of biogeocenosis, the number of species of living organisms included in it gradually increases. The community becomes more complex, it becomes more and more branched. The variety of connections that exist between organisms increases. The community uses the resources of the environment more and more fully. This is how it turns into a mature one, which is well adapted to environmental conditions and has self-regulation. In it, species populations reproduce well and are not replaced by other species. The described change of biogeocenoses lasts for thousands of years. However, there are changes that occur before the eyes of just one generation of people. For example, this is the overgrowing of small bodies of water.
So, we talked about what biogeocenosis is. The examples with descriptions presented above give a clear idea of it. Everything we have talked about is important for understanding this topic. Types of biogeocenoses, their structure, features, examples - all this should be studied in order to have a complete understanding of them.
