Ecological systems and their characteristics presentation. Ecological systems presentation. heterotrophs that decompose organic matter

History of the term The concept of an ecosystem The structure of an ecosystem Mechanisms of ecosystem functioning Spatial boundaries of an ecosystem (chorological aspect) Spatial boundaries of an ecosystem (chorological aspect) Time boundaries of an ecosystem (chronological aspect) Time boundaries of an ecosystem (chronological aspect) Ranks of ecosystems Artificial ecosystems

The ideas of the unity of all living things in nature, its interaction and conditioning of processes in nature date back to ancient times. However, the concept began to acquire a modern interpretation at the turn of the 19th century. Thus, the German hydrobiologist K. Möbius in 1877 described the oyster jar as a community of organisms and gave it the name "biocenosis". In the classic work of the American biologist S. Forbes, the lake with the entire totality of organisms is defined as a "microcosm" ("The lake as a microcosm" "The lake as a microcosme", 1887). The modern term was first proposed by the English ecologist A. Tensley in 1935. V.V.Dokuchaev also developed the concept of biocenosis as an integral system. However, in Russian science, the concept of biogeocenosis (1944), introduced by V.N.Sukachev, has become generally accepted. In related sciences, there are also various definitions, which to one degree or another coincide with the concept of "ecosystem", for example, "geosystem" in geoecology or introduced at about the same period by other scientists "Holocene" (F. Clements, 1930) and "bioinert body "(V. I. Vernadsky, 1944).

Definitions Any unity that includes all organisms in a given area and interacts with the physical environment in such a way that the flow of energy creates a clearly defined trophic structure, species diversity and the cycle of substances (exchange of substances and energy between biotic and abiotic parts) within the system, is an ecological system , or ecosystem (Yu. Odum, 1971). Ecosystem is a system of physical, chemical and biological processes (A. Tensley, 1935). The community of living organisms, together with the inanimate part of the environment in which it is located, and all the various interactions are called an ecosystem (D.F. Owen.). Any set of organisms and inorganic components of their environment, in which the circulation of substances can take place, is called an ecological system or ecosystem (V.V.Denisov). Biogeocenosis (V.N.Sukachev, 1944) is an interdependent complex of living and inert components interconnected by the exchange of matter and energy. Sometimes it is especially emphasized that an ecosystem is a historically formed system.

Ecosystem Concept Ecosystem is a complex self-organizing, self-regulating and self-developing system. The main characteristic of an ecosystem is the presence of relatively closed, stable in space and time flows of matter and energy between the biotic and abiotic parts of the ecosystem. It follows from this that not every biological system can be called an ecosystem, for example, An aquarium or rotten tree stump are not such. These biological systems are not sufficiently self-sufficient and self-regulating, if you stop regulating the conditions and maintain the characteristics at the same level, it will quickly collapse. Such communities do not form independent closed cycles of matter and energy, but are only part of a larger system. Such systems should be called communities of a lower rank, or microcosms. Sometimes the concept of facies is used for them (for example, in geoecology), but it is not able to fully describe such systems, especially those of artificial origin. V general case In different sciences, the concept of "facies" corresponds to different definitions: from systems of the subecosystem level to concepts that are not related to an ecosystem, or a concept that unites homogeneous ecosystems, or is almost identical to the definition of an ecosystem.

Eugene Odum (). Father of ecosystem ecology

V.N.Sukachev (). The author of the term biogeocenosis The ecosystem is an open system and is characterized by input and output flows of matter and energy. The basis of the existence of almost any ecosystem is the flow of energy of sunlight, which is a consequence of a thermonuclear reaction, in direct (photosynthesis) or indirect (decomposition of organic matter), with the exception of deep-sea ecosystems: "black" and "white smokers, the source of energy in which is internal heat earth and energy of chemical reactions.

Biogeocenosis and ecosystem In accordance with the definitions between the concepts of "ecosystem" and "biogeocenosis" there is no difference, biogeocenosis can be considered a complete synonym for the term ecosystem. However, there is a widespread opinion that a biogeocenosis can serve as an analogue of an ecosystem at the very initial level, since the term “biogeocenosis” emphasizes the relationship of a biocenosis with a specific area of ​​land or aquatic environment, while an ecosystem presupposes any abstract area. Therefore, biogeocenoses are usually considered a special case of an ecosystem. In the definition of the term biogeocenosis, various authors list specific biotic and abiotic components of biogeocenosis, while the definition of an ecosystem is more general.

The ecosystem can be divided into two components, biotic and abiotic. Biotic is divided into autotrophic and heterotrophic components that form the trophic structure of the ecosystem. The only source of energy for the existence of the ecosystem and the maintenance of various processes in it are producers, which absorb the energy of the sun with an efficiency of 0.1 to 1%, rarely 3 to 4.5% of the initial amount. Autotrophs represent the first trophic level of the ecosystem. Subsequent trophic levels of the ecosystem are formed at the expense of consumers and are closed by reducers, which convert nonliving organic matter into a mineral form that can be assimilated by an autotrophic element.

The main components of the ecosystem From the point of view of the structure in the ecosystem, there are: the climatic regime, which determines the temperature, humidity, lighting regime and other physical characteristics of the environment; inorganic substances included in the circulation; organic compounds that bind biotic and abiotic parts in the cycle of matter and energy; producers are organisms that create primary products; macroconsumptions, or phagotrophs, heterotrophs that eat other organisms or large particles of organic matter; microconsuments (saprotrophs) heterotrophs, mainly fungi and bacteria that destroy dead organic matter, mineralizing it, thereby returning it to the circulation. The last three components form the biomass of the ecosystem.

From the point of view of the functioning of the ecosystem, the following functional blocks of organisms are distinguished (in addition to autotrophs): biophages, organisms that eat other living organisms, saprophages, organisms that eat dead organic matter. This division shows the temporal-functional relationship in the ecosystem, focusing on the division in time of the formation of organic matter and its redistribution within the ecosystem (biophages) and processing by saprophages. A significant period of time can elapse between the dying off of organic matter and the re-inclusion of its constituents in the cycle of matter in the ecosystem, for example, in the case of a pine log, 100 or more years. All these components are interconnected in space and time and form a single structural and functional system.

Usually the concept of ecotope was defined as a habitat of organisms, characterized by a certain combination of ecological conditions: soils, grounds, microclimate, etc. However, in this case, this concept is almost identical to the concept of climatopes. At the moment, an ecotope, in contrast to a biotope, is understood as a certain territory or water area with the entire set and characteristics of soils, grounds, microclimate and other factors in an unchanged form by organisms. Examples of an ecotope are alluvial soils, newly formed volcanic or coral islands, man-dug quarries, and other newly formed territories. In this case, the climatopes are part of the ecotope.

Initially, "climatopes" were defined by V.N.Sukachev (1964) as the air part of the biogeocenosis, which differs from the surrounding atmosphere in its gas composition, especially in the concentration of carbon dioxide in the surface biohorizon, oxygen in the same place and in biohorizons of photosynthesis, air regime, saturation with biolines, reduced and altered solar radiation and illumination, the presence of luminescence of plants and some animals, a special thermal regime and air humidity regime. At the moment, this concept is interpreted a little more broadly: as a characteristic of biogeocenosis, a combination of physical and chemical characteristics of the air or water environment, essential for organisms inhabiting this environment. The climatoppe sets on a long-term scale the basic physical characteristics of the existence of animals and plants, defining the range of organisms that can exist in a given ecosystem.

Edaphotope The edaphotope is usually understood as the soil as a constituent element of the ecotope. However, this concept should be more accurately defined as a part of the inert environment transformed by organisms, that is, not all the soil, but only a part of it. Soil (edaphotop) is the most important component of the ecosystem: it closes the cycles of matter and energy, transfers from dead organic matter into mineral matter and their involvement in living biomass]. The main carriers of energy in the edaphotope are organic carbon compounds, their labile and stable forms, they determine the soil fertility to the greatest extent. ]

A biotope is an ecotope transformed by a biota or, more precisely, a section of a territory that is homogeneous in terms of living conditions for certain species of plants or animals, or for the formation of a certain biocenosis. Biocenosis is a historically formed set of plants, animals, microorganisms inhabiting a land or water body (biotope). Competition and natural selection play an important role in the formation of biocenosis. The main unit of the biocenosis is a consortium, since any organisms are more or less associated with autotrophs and form complex system consorts of various orders, and this network is a consort of an increasing order and may indirectly depend on an increasing number of consortium determinants. It is also possible to divide the biocenosis into phytocoenosis and zoocoenosis. A phytocenosis is a set of plant populations of one community, which form the determinants of consortia. A zoocenosis is a set of animal populations that are consorts of a different order and serve as a mechanism for the redistribution of matter and energy within an ecosystem (see the functioning of ecosystems). Biotope and biocenosis together form a biogeocenosis / ecosystem.

Stability of ecosystems An ecosystem can be described by a complex scheme of forward and backward connections that maintain the homeostasis of the system within certain limits of parameters the environment... Thus, within certain limits, the ecosystem is able to maintain its structure and functions relatively unchanged under external influences. Usually, two types of homeostasis are distinguished: the resistant ability of ecosystems to maintain structure and functions under negative external influences and the elastic ability of the ecosystem to restore structure and functions when some of the ecosystem components are lost.

Sometimes the third aspect of the sustainability of the ecosystem is distinguished in relation to changes in the characteristics of the environment and changes in its internal characteristics... If the ecosystem functions steadily in a wide range of environmental parameters and the ecosystem contains a large number of interchangeable species, such a community is called dynamically stable. In the opposite case, when an ecosystem can exist in a very limited set of environmental parameters, and most species are irreplaceable in their functions, such a community is called dynamically fragile]. It should be noted that given characteristic in general, it does not depend on the number of species and the complexity of communities. A classic example is the Great Barrier Reef off the coast of Australia, which is one of the world's biodiversity hotspots. Symbiotic algae of corals, dinoflagellates, are very sensitive to temperature. A deviation from the optimum by literally a couple of degrees leads to the death of algae, and polyps receive up to% of nutrients from the photosynthesis of their mutualists. ]

Different states of equilibrium of systems (illustration) An ecosystem has many states in which it is in dynamic equilibrium; in case of withdrawal from it external forces, the ecosystem does not necessarily return to its original state, it is often attracted by the nearest equilibrium state, although it can be very close to the initial one.

Usually, resilience has been associated and associated with the biodiversity of species in the ecosystem, that is, the higher the biodiversity, the more complex the organization of communities, the more complex the food webs, the higher the resilience of ecosystems. But already 40 and more years ago on this question there have been different points of view, and at the moment the most widespread opinion is that both local and general resilience of an ecosystem depend on a much larger set of factors than just the complexity of communities and biodiversity. So, at the moment, an increase in biodiversity is usually associated with an increase in complexity, the strength of connections between the components of the ecosystem, the stability of the flows of matter and energy between the components. The importance of biodiversity lies in the fact that it allows the formation of many communities, different in structure, form, function, and provides a sustainable opportunity for their formation. The higher the biodiversity, the more communities can exist, the more diverse reactions (from the point of view of biogeochemistry) can be carried out, ensuring the existence of the biosphere as a whole.

In nature, there are no clear boundaries between different ecosystems. You can always point to a particular ecosystem, but it is not possible to single out discrete boundaries if they are not represented by various landscape factors (cliffs, rivers, various hillsides, rock outcrops, etc.), it is not possible, there are always smooth transitions from one ecosystems to another. This is due to a relatively smooth change in the gradient of environmental factors (humidity, temperature, humidity, etc.). Sometimes transitions from one ecosystem to another can actually be an independent ecosystem. Usually communities that form at the junction of different ecosystems are called ecotones. The term "ecotone" was introduced by F. Clements in 1905.

Ecotones Ecotones play a significant role in maintaining the biological diversity of ecosystems due to the so-called edge effect of combining a complex of environmental factors of various ecosystems, which causes a greater variety of environmental conditions, therefore, licenses and ecological niches. Thus, the existence of species from one or another ecosystem, as well as species specific to the ecotone (for example, vegetation of coastal aquatic habitats), is possible.

Different ecosystems exist in the same biotope over time. The change from one ecosystem to another can take both rather long and relatively short (several years) periods of time. The duration of the existence of ecosystems in this case is determined by the stage of succession. A change in ecosystems in a biotope can also be caused by catastrophic processes, but in this case, the biotope itself changes significantly, and such a change is not usually called a succession (with some exceptions, when a catastrophe, for example, a fire, is a natural stage of a cyclic succession).

Succession A succession is a sequential, natural replacement of some communities by others in a certain area of ​​the internal factors development of ecosystems. Each previous community predetermines the conditions for the existence of the next and its own disappearance. This is due to the fact that in ecosystems that are transitional in succession, there is an accumulation of matter and energy, which they are no longer able to include in the cycle, the transformation of the biotope, changes in the microclimate and other factors, and thus a material and energy base is created, as well as the environmental conditions necessary for the formation of subsequent communities. However, there is another model that explains the mechanism of succession as follows: the species of each previous community are replaced only by successive competition, inhibiting and "resisting" the introduction of subsequent species. However, this theory considers only the competitive relationship between species, not describing the whole picture of the ecosystem as a whole. Of course, such processes are going on, but the competitive displacement of the previous species is possible precisely because of their transformation of the biotope. Thus, both models describe different aspects of the process and are correct at the same time.

Succession is autotrophic and heterotrophic. At the early stages of the autotrophic succession sequence, the P / R ratio is much greater than unity, since usually primary communities have high productivity, but the structure of the ecosystem has not yet been fully formed, and there is no way to utilize this biomass. Consistently, with the complication of the communities, with the complication of the ecosystem structure, the costs of respiration (R) grow, as more and more heterotrophs appear responsible for the redistribution of material-energy flows, the P / R ratio tends to unity and is in fact the same for the terminal community (ecosystem ). Heterotrophic succession has the opposite characteristics: in it, the P / R ratio in the early stages is much less than unity and gradually increases as we move through the succession stages.

The issue of ranking ecosystems is rather complicated. The identification of minimal ecosystems (biogeocenoses) and ecosystems of the highest rank of the biosphere is beyond doubt. Intermediate allocations are rather complicated, since the complexity of the psychological aspect does not always unambiguously allow determining the boundaries of ecosystems. In geoecology (and landscape science), there is the following ranking: facies tract (ecosystem) landscape geographic area geographic area biome biosphere. In ecology, there is a similar ranking, however, it is generally believed that it is correct to single out only one intermediate ecosystem of the biome.

Biomes Biome is a large system-geographic (ecosystem) subdivision within the natural-climatic zone (Reimers NF). According to R. H. Whittaker, a group of ecosystems of a given continent that have a similar structure or physiognomy of vegetation and the general nature of environmental conditions. This definition is somewhat incorrect, since there is a link to a specific continent, and some biomes are present on different continents, for example, a tundra biome or a steppe biome. At the moment, the most generally accepted definition is: "A biome is a set of ecosystems with a similar type of vegetation located in the same natural and climatic zone" (Akimova T.A., Khaskin V.V.). What these definitions have in common is that in any case, a biome is a set of ecosystems of one natural and climatic zone. Biosphere The biosphere covers the entire surface of the Earth, covering it with a film of living matter. The term biosphere was introduced by Jean-Baptiste Lamarck at the beginning of the 19th century, and in geology it was proposed by the Austrian geologist Eduard Suess in 1875. However, the creation of a holistic theory of the biosphere belongs to the Russian scientist Vladimir Ivanovich Vernadsky. The biosphere is an ecosystem of a higher order that unites all other ecosystems and ensures the existence of life on Earth. The biosphere includes: atmosphere, hydrosphere, lithosphere, pedosphere.
Artificial ecosystems are ecosystems created by man, for example, agrocenoses, natural-economic systems or Biosphere 2. Artificial ecosystems have the same set of components as natural ones: producers, consumers and decomposers, but there are significant differences in the redistribution of matter and energy flows.

summaries of presentations

Ecosystems

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Biogeocenology. Ecosystem and biogeocenosis. Features of ecosystems. Open (there are incoming and outgoing energy flows) Autonomous. Possesses homeostasis - relative stability in time and space. Blurred borders, both vertically and horizontally. Can exist without any component. Ecotone is the border between ecosystems (biogeocenoses). Ecosystem classification. By the size of the Macro ecosystem. For example, sea, ocean, continent ... Meso ecosystems. For example, a forest area, field, meadow, river, lake ... Such ecosystems are usually called biogeocenoses. Micro ecosystems (forest edge, meadow, puddle ...). - Ecosystems.ppt

Parts of the ecosystem

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Ecosystems and their constituent parts. Ecosystem, its composition and type. Ecosystem = biocenosis + biotope. Types of ecological systems. The structure of ecosystems. Spatial structure. Tiering is a phenomenon of vertical stratification of biocenoses. In the forest, up to six tiers are often distinguished. Meadow communities can also be dismembered. Each specific ecosystem has a species structure. Trophic structure of biocenosis. Energy and Ecosystem Productivity. The energy is dissipated. Each ecosystem has a certain productivity. Primary productivity of the system. Consumptions. Ecological pyramids. - Parts of the ecosystem.ppt

Ecosystem concepts

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Fundamentals of Ecology. Ecosystem. The main functional unit in ecology. Basic concepts. System properties. Living organisms. Homeostasis. Ecological homeostasis. Homeostasis mechanisms. Eugene Odum. Ecosystem concept. A. Tensley. Vladimir Nikolaevich Sukachev. Biogeocenosis. Biogeocenosis is formed by biotope and biocenosis. Ecosystem structure. The ecosystem is an open system. Nikolay Fedorovich Reimers. Ecosystem structure according to Reimers. Abiotic component. Climatop. Territory or water area. Soil as an integral element of the ecotope. Biotope. Biocenosis. Producers. Substrate environment. - Ecosystem Concepts.pptx

Ecosystem structure

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Topic: "The structure of ecosystems" Plan. I. Ecosystem, biogeocenosis, definition, properties. The structure of ecosystems. Sukachev Vladimir Nikolaevich. Created in 1964 the doctrine of forest biogeocenology. Founder of the school of forest typologists. Author of a number of textbooks and manuals on dendrology, geobotany and works on Darwinism. A. Tensley. Ecosystem is the basic concept of ecology. The term was proposed in 1935 by the English ecologist A. Tensley. Biocenosis. Plants. Animals. Microorganisms. Biotope. Atmosphere. Hydrosphere. Lithosphere. Biogeocenosis. Substance, energy, information. Ecosystem structure. Dubrava. - Ecosystem structure.ppt

Ecosystem structure

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Ecosystem structure. Stream ecosystem. Together with the factors of inanimate nature, the community forms an ecosystem. An ecosystem, the boundaries of which are determined by the plant community, is called biogeocenosis. The totality of the biogeocenoses of the earth forms a global ecosystem - the biosphere. Terrestrial biogeocenosis. Spatial structure of the ecosystem. The spatial structure of most ecosystems is determined by the layering of vegetation. The species structure of the ecosystem. The ecological structure of the ecosystem. The ratio of groups of species that occupy certain ecological niches and perform certain functions in the community. - Ecosystem structure.ppt

Condition of ecosystems

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Millennium Ecosystem Assessment. The largest project. Ecosystem services. Consequences of changes in ecosystems. The structure of the program. Review of the program outputs. Humanity. Unprecedented change. Biogeochemical cycles. Irreversible changes in biodiversity. Ecosystem changes. Changes imposed on ecosystems. Degradation of ecosystem services. The state of the provisioning services. The state of regulatory and cultural services. Significant damage. Decrease in national wealth. Increased likelihood of non-linear changes. Examples of non-linear changes. Poverty rate. Ecosystem services and poverty alleviation. - State of ecosystems.ppt

Ecosystem Biology

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Ecosystem level. The main components of the ecosystem. On which the features of energy transfer and the circulation of matter depend. According to the type of nutrition, organisms are divided into autotrophs. And heterotrophs. The main channel for energy transfer in a community is the food chain. Changes in the intensity of energy flows lead to characteristic ratios of the number and biomass of organisms occupying different trophic levels. The higher the trophic level. Communities change over time. - Ecosystem Biology.ppt

Natural ecosystems

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Ecosystems. The concept of ecosystems. Ecosystem. Biogeocenosis. Ecosystem classification. Major land biomes. The main types of natural ecosystems and biomes. Types of freshwater ecosystems. Zoning of ecosystems. Periodic law of geographic zoning. Natural systems. The principle of ecosystem formation. Ecosystem structure. Energy flow in ecosystems. Food chains and trophic levels. Mixed forest ecosystem food web. Grassland ecosystem food web. The food web of the ecosystem of the reservoir. Producers. Rule 10%. Ecological pyramids. Biomass pyramid. Food pyramid. Accumulation of contaminants in food webs. - Natural ecosystems.ppt

Organisms in the ecosystem

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Ecosystems of the Earth. Ecosystem structure. Living population + abiotic environmental conditions. How are the concepts of biogeocenosis and ecosystem related? Biogeocenosis. Ecosystem. The supraspecific level of organization of biosystems. Characteristics of the Ecosystem. Basic properties-signs. Producers Consumables Reducers. The magnitude and speed of the unidirectional flow of energy determines the health of the ecosystem. Diagram of the movement of energy in the ecosystem. Energy of sun. Chemical energy. Mechanical energy. Thermal waste. Rice. 2. Energy flows from the Sun through green plants to animals. The flow of energy into the ecosystem. - Organisms in the ecosystem.pptx

Types of ecosystems

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Ecology. What is an ecosystem? Types of ecosystems: Marine ecosystems: Mountain ecosystems: Meadow ecosystems: Steppe ecosystems: Tundra ecosystems: Desert ecosystems: Swamp ecosystems: Freshwater ecosystems: Anthropogenic (artificial) ecosystems are created by man in the process of economic activity. Marine ecosystems are strongly influenced by human economic activities. Mountains occupy significant land areas. The basis of meadow herbage is cereals. The steppes are located on the plains and along the southern slopes of the mountains. Today, European steppes on lowland chernozems can only be seen in reserves. - Types of ecosystems.ppt

Ecosystem classification

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Ecosystem classification. Determination of the ecological system. Hierarchy of ecosystems. Life zones in an oceanic ecosystem. Zones in the ecosystem of a stagnant continental reservoir. Regularities of the geographical distribution of ecosystems. The law of geographic zoning. - Ecosystem classification.ppt

Succession

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Self-development of the ecosystem. Target. The concept of a change in biogeocenosis. Both stable and unstable ecosystems exist in nature. What happens to the arable field if you stop cultivating it. What will happen to the community after the fire. What will happen to the community when the lake is gradually overgrown. What is succession. The succession is run by the community itself. What could be the reason for the change in the community. Human activities. Endogenetic change. V.N. Sukachev. What is the main reason for the fragility of ecosystems. There are three types of balance in biocenoses. Changes in the amount of biomass in the ecosystem. - Succession.ppt

Change of successions

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Self-development of ecosystems - succession. Talk about fires. Wheat. Interrelation of meadow clover in the agrocenosis. Cultivated plants. Self-development of ecosystems. River flooding rate. Consistent regular change of biocenoses. Changes of successions. American ecologist Clements. Primary succession. Development of one ecosystem. Changing of the climate. Anthropogenic impacts. Fires. Forest fire. The main causes of forest fires. Damaging factors of forest and peat fires. Termination of aircraft flights. Types of forest fires. By the speed of spread of fire and the height of the flame. Horse fire. - Change of successions.ppt

Changing communities

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Biology lesson. Ecological success. Biological dictation. Lesson topic: Ecological successions. Anchor points of the lesson. Protection of biogeocenoses. Types of biogeocenosis change. Gradual (Successions) Changes in the environment by the organisms themselves. Climate change In the process of evolution. Abrupt, sudden, "catastrophic" Natural disasters Anthropogenic factor. Succession. F. Clements called such a community climax. Classification of successions. Stages of succession. General laws of succession. Stages of the primary succession. Change of natural communities. The action of the plants themselves on each other. Anthropogenic factor in the change of biogecenosis. - Change communities.ppt

Changing ecosystems

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Fundamentals of Ecology. Ecosystems. Topic: Properties of ecosystems. Change of ecosystems. Objectives: To form knowledge about the mechanisms of self-regulation that ensure the sustainability of ecosystems. 1. Self-regulation. Self-regulation is characteristic of any biogeocenosis. The exclusion of control "from above" can lead to very serious consequences. The absence of natural enemies in the Colorado potato beetle reduces potato yields in Eurasia. Ambrosia in Russia also has no control from above. 2. Change of ecosystems. Such a natural change in biogeocenoses is called succession. A succession that begins at a place completely devoid of life is called primary. - Ecosystem change.ppt

Ecosystem change

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Ecosystem changes. Ecosystems. Variety of interspecies relationships. Biological terms. Regularities of the relationship of living organisms. Relationship type. Legume interactions. Nodule bacteria. Pick three correct answers. Abiotic factors. Comparison of biological objects. Ascaris. Establishing a sequence of processes. Food chain. Morning hours. Leaves evaporate a lot of moisture. The study new topic... Consolidation of the studied material. Stagnant lake. Homework... Prepared the presentation. -

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Presentation on the topic: Ecosystems

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History of the term History of the term The concept of an ecosystem The structure of an ecosystem Mechanisms of ecosystem functioning Spatial boundaries of an ecosystem (chorological aspect) Time boundaries of an ecosystem (chronological aspect) Ranks of ecosystems Artificial ecosystems

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The ideas of the unity of all living things in nature, its interaction and conditioning of processes in nature date back to ancient times. However, the concept began to acquire a modern interpretation at the turn of the XIX-XX centuries. Thus, the German hydrobiologist K. Möbius in 1877 described the oyster jar as a community of organisms and gave it the name "biocenosis". In the classic work of the American biologist S. Forbes, the lake with the entire totality of organisms is defined as a "microcosm" ("The lake as a microcosm" - "The lake as a microcosme", 1887). The modern term was first proposed by the English ecologist A. Tensley in 1935. V.V.Dokuchaev also developed the concept of biocenosis as an integral system. However, in Russian science, the concept of biogeocenosis (1944), introduced by V.N.Sukachev, has become generally accepted. In related sciences, there are also various definitions, which to one degree or another coincide with the concept of "ecosystem", for example, "geosystem" in geoecology or introduced at about the same period by other scientists "Holocene" (F. Clements, 1930) and "bioinert body "(V. I. Vernadsky, 1944). The ideas of the unity of all living things in nature, its interaction and conditioning of processes in nature date back to ancient times. However, the concept began to acquire a modern interpretation at the turn of the XIX-XX centuries. Thus, the German hydrobiologist K. Möbius in 1877 described the oyster jar as a community of organisms and gave it the name "biocenosis". In the classic work of the American biologist S. Forbes, the lake with the entire totality of organisms is defined as a "microcosm" ("The lake as a microcosm" - "The lake as a microcosme", 1887). The modern term was first proposed by the English ecologist A. Tensley in 1935. V.V.Dokuchaev also developed the concept of biocenosis as an integral system. However, in Russian science, the concept of biogeocenosis (1944), introduced by V.N.Sukachev, has become generally accepted. In related sciences, there are also various definitions, which to one degree or another coincide with the concept of "ecosystem", for example, "geosystem" in geoecology or introduced at about the same period by other scientists "Holocene" (F. Clements, 1930) and "bioinert body "(V. I. Vernadsky, 1944).

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Any unity that includes all organisms in a given area and interacts with the physical environment in such a way that the flow of energy creates a clearly defined trophic structure, species diversity and the cycle of substances (exchange of substances and energy between biotic and abiotic parts) within the system, is an ecological system, or an ecosystem (Yu. Odum, 1971). Ecosystem is a system of physical, chemical and biological processes (A. Tensley, 1935). The community of living organisms, together with the inanimate part of the environment in which it is located, and all the various interactions are called an ecosystem (D.F. Owen.). Any set of organisms and inorganic components of their environment, in which the circulation of substances can take place, is called an ecological system or ecosystem (V.V.Denisov). Biogeocenosis (V.N.Sukachev, 1944) is an interdependent complex of living and inert components interconnected by the exchange of matter and energy. Sometimes it is especially emphasized that an ecosystem is a historically formed system.

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An ecosystem is a complex self-organizing, self-regulating and self-developing system. The main characteristic of an ecosystem is the presence of relatively closed, stable in space and time flows of matter and energy between the biotic and abiotic parts of the ecosystem. It follows from this that not every biological system can be called an ecosystem, for example, An aquarium or rotten tree stump are not such. These biological systems are not sufficiently self-sufficient and self-regulating, if you stop regulating the conditions and maintain the characteristics at the same level, it will quickly collapse. Such communities do not form independent closed cycles of matter and energy, but are only part of a larger system. Such systems should be called communities of a lower rank, or microcosms. Sometimes the concept of facies is used for them (for example, in geoecology), but it is not able to fully describe such systems, especially those of artificial origin. In general, in different sciences, the concept of "facies" corresponds to different definitions: from systems of the sub-ecosystem level to concepts that are not related to an ecosystem, or a concept that unites homogeneous ecosystems, or is almost identical to the definition of an ecosystem.

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In accordance with the definitions, there is no difference between the concepts of "ecosystem" and "biogeocenosis," biogeocenosis can be considered a complete synonym for the term ecosystem. However, there is a widespread opinion that a biogeocenosis can serve as an analogue of an ecosystem at the very initial level, since the term “biogeocenosis” focuses more on the relationship of a biocenosis with a specific area of ​​land or aquatic environment, while an ecosystem assumes any abstract area. Therefore, biogeocenoses are usually considered a special case of an ecosystem. In the definition of the term biogeocenosis, various authors list specific biotic and abiotic components of biogeocenosis, while the definition of an ecosystem is more general.

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The ecosystem can be divided into two components - biotic and abiotic. Biotic is divided into autotrophic and heterotrophic components that form the trophic structure of the ecosystem. The ecosystem can be divided into two components - biotic and abiotic. Biotic is divided into autotrophic and heterotrophic components that form the trophic structure of the ecosystem. The only source of energy for the existence of an ecosystem and the maintenance of various processes in it are producers, absorbing the energy of the sun with an efficiency of 0.1 - 1%, rarely 3 - 4.5% of the initial amount. Autotrophs represent the first trophic level of the ecosystem. Subsequent trophic levels of the ecosystem are formed at the expense of consumers and are closed by reducers, which convert nonliving organic matter into a mineral form that can be assimilated by an autotrophic element.

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From the point of view of structure, the ecosystem is distinguished: climatic regime, which determines temperature, humidity, lighting regime and other physical characteristics of the environment; inorganic substances included in the circulation; organic compounds that bind biotic and abiotic parts in the cycle of matter and energy; producers - organisms that create primary products; macroconsumptions, or phagotrophs, are heterotrophs that eat other organisms or large particles of organic matter; microconsumptions (saprotrophs) are heterotrophs, mainly fungi and bacteria that destroy dead organic matter, mineralizing it, thereby returning it to the circulation. The last three components form the biomass of the ecosystem.

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From the point of view of the functioning of the ecosystem, the following functional blocks of organisms are distinguished (in addition to autotrophs): From the point of view of the functioning of the ecosystem, the following functional blocks of organisms are distinguished (in addition to autotrophs): biophages - organisms that eat other living organisms, saprophages - organisms that eat dead organic matter. This division shows the temporal-functional relationship in the ecosystem, focusing on the division in time of the formation of organic matter and its redistribution within the ecosystem (biophages) and processing by saprophages. A significant period of time can elapse between the dying off of organic matter and the re-inclusion of its constituents in the cycle of matter in the ecosystem, for example, in the case of a pine log, 100 or more years. All these components are interconnected in space and time and form a single structural and functional system.

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Usually the concept of ecotope was defined as a habitat of organisms, characterized by a certain combination of ecological conditions: soils, grounds, microclimate, etc. However, in this case, this concept is almost identical to the concept of climatopes. Usually the concept of ecotope was defined as a habitat of organisms, characterized by a certain combination of ecological conditions: soils, grounds, microclimate, etc. However, in this case, this concept is almost identical to the concept of climatopes. At the moment, an ecotope, in contrast to a biotope, is understood as a certain territory or water area with the entire set and characteristics of soils, grounds, microclimate and other factors in an unchanged form by organisms. Examples of an ecotope are alluvial soils, newly formed volcanic or coral islands, quarries dug by man, and other newly formed territories. In this case, the climatopes are part of the ecotope.

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Initially, "climatopes" were defined by V.N.Sukachev (1964) as the air part of the biogeocenosis, which differs from the surrounding atmosphere in its gas composition, especially in the concentration of carbon dioxide in the surface biohorizon, oxygen in the same place and in biohorizons of photosynthesis, air regime, saturation with biolines, reduced and altered solar radiation and illumination, the presence of luminescence of plants and some animals, a special thermal regime and air humidity regime. Initially, "climatopes" were defined by V.N.Sukachev (1964) as the air part of the biogeocenosis, which differs from the surrounding atmosphere in its gas composition, especially in the concentration of carbon dioxide in the surface biohorizon, oxygen in the same place and in biohorizons of photosynthesis, air regime, saturation with biolines, reduced and altered solar radiation and illumination, the presence of luminescence of plants and some animals, a special thermal regime and air humidity regime. At the moment, this concept is interpreted a little more broadly: as a characteristic of biogeocenosis, a combination of physical and chemical characteristics of the air or water environment, essential for organisms inhabiting this environment. The climatoppe sets on a long-term scale the basic physical characteristics of the existence of animals and plants, defining the range of organisms that can exist in a given ecosystem.

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The edaphotope is usually understood as the soil as a constituent element of the ecotope. However, this concept should be more accurately defined as a part of the inert environment transformed by organisms, that is, not all the soil, but only a part of it. Soil (edaphotop) is the most important component of the ecosystem: it closes the cycles of matter and energy, transfers from dead organic matter into mineral matter and their involvement in living biomass]. The main carriers of energy in the edaphotope are organic carbon compounds, their labile and stable forms, they determine the soil fertility to the greatest extent.

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A biotope is an ecotope transformed by a biota or, more precisely, a plot of territory that is homogeneous in terms of living conditions for certain species of plants or animals, or for the formation of a certain biocenosis. A biotope is an ecotope transformed by a biota or, more precisely, a section of a territory that is homogeneous in terms of living conditions for certain species of plants or animals, or for the formation of a certain biocenosis. Biocenosis is a historically formed set of plants, animals, microorganisms inhabiting a land area or water body (biotope). Competition and natural selection play an important role in the formation of biocenosis. The main unit of the biocenosis is a consortium, since any organisms are to one degree or another associated with autotrophs and form a complex system of consorts of various orders, and this network is a consort of an increasing order and may indirectly depend on an increasing number of consortia determinants. It is also possible to divide the biocenosis into phytocoenosis and zoocoenosis. A phytocenosis is a set of plant populations of one community, which form the determinants of consortia. A zoocenosis is a set of animal populations that are consorts of a different order and serve as a mechanism for the redistribution of matter and energy within an ecosystem (see the functioning of ecosystems). Biotope and biocenosis together form a biogeocenosis / ecosystem.

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Stability of ecosystems Stability of ecosystems An ecosystem can be described by a complex scheme of forward and backward connections that maintain the homeostasis of the system within certain limits of environmental parameters. Thus, within certain limits, the ecosystem is able to maintain its structure and functions relatively unchanged under external influences. Usually, two types of homeostasis are distinguished: resistant - the ability of ecosystems to maintain structure and functions under negative external influences and elastic - the ability of an ecosystem to restore structure and functions with the loss of part of the ecosystem components.

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Sometimes the third aspect of sustainability is distinguished - the sustainability of an ecosystem in relation to changes in the characteristics of the environment and changes in its internal characteristics. If the ecosystem functions steadily in a wide range of environmental parameters and the ecosystem contains a large number of interchangeable species, such a community is called dynamically stable. In the opposite case, when an ecosystem can exist in a very limited set of environmental parameters, and most species are irreplaceable in their functions, such a community is called dynamically fragile]. It should be noted that this characteristic, in the general case, does not depend on the number of species and the complexity of communities. A classic example is the Great Barrier Reef off the coast of Australia, which is one of the "hot spots" of biodiversity in the world - symbiotic algae of corals, dinoflagellates, are very sensitive to temperature. A deviation from the optimum by literally a couple of degrees leads to the death of algae, and polyps receive up to 50-60% of their nutrients from the photosynthesis of their mutualists. Sometimes the third aspect of sustainability is distinguished - the sustainability of an ecosystem in relation to changes in the characteristics of the environment and changes in its internal characteristics. If the ecosystem functions steadily in a wide range of environmental parameters and the ecosystem contains a large number of interchangeable species, such a community is called dynamically stable. In the opposite case, when an ecosystem can exist in a very limited set of environmental parameters, and most species are irreplaceable in their functions, such a community is called dynamically fragile]. It should be noted that this characteristic, in the general case, does not depend on the number of species and the complexity of communities. A classic example is the Great Barrier Reef off the coast of Australia, which is one of the "hot spots" of biodiversity in the world - symbiotic algae of corals, dinoflagellates, are very sensitive to temperature. A deviation from the optimum by literally a couple of degrees leads to the death of algae, and polyps receive up to 50-60% of their nutrients from the photosynthesis of their mutualists.

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Usually, resilience has been associated and associated with the biodiversity of species in the ecosystem, that is, the higher the biodiversity, the more complex the organization of communities, the more complex the food webs, the higher the resilience of ecosystems. But already 40 and more years ago, there were different points of view on this issue, and at the moment the most widespread opinion is that both local and general sustainability of an ecosystem depend on a much larger set of factors than just the complexity of communities and biodiversity. So, at the moment, an increase in biodiversity is usually associated with an increase in complexity, the strength of connections between the components of the ecosystem, the stability of the flows of matter and energy between the components. Usually, resilience has been associated and associated with the biodiversity of species in the ecosystem, that is, the higher the biodiversity, the more complex the organization of communities, the more complex the food webs, the higher the resilience of ecosystems. But already 40 or more years ago, there were different points of view on this issue, and at the moment the most widespread opinion is that both local and general sustainability of an ecosystem depend on a much larger set of factors than just the complexity of communities and biodiversity. So, at the moment, an increase in biodiversity is usually associated with an increase in complexity, the strength of connections between the components of the ecosystem, the stability of the flows of matter and energy between the components. The importance of biodiversity lies in the fact that it allows the formation of many communities, different in structure, form, function, and provides a sustainable opportunity for their formation. The higher the biodiversity, the more communities can exist, the more diverse reactions (from the point of view of biogeochemistry) can be carried out, ensuring the existence of the biosphere as a whole.

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In nature, there are no clear boundaries between different ecosystems. You can always point to a particular ecosystem, but it is not possible to single out discrete boundaries if they are not represented by various landscape factors (cliffs, rivers, various hillsides, rock outcrops, etc.), it is not possible, there are always smooth transitions from one ecosystems to another. This is due to a relatively smooth change in the gradient of environmental factors (humidity, temperature, humidity, etc.). Sometimes transitions from one ecosystem to another can actually be an independent ecosystem. Usually communities that form at the junction of different ecosystems are called ecotones. The term "ecotone" was introduced by F. Clements in 1905. In nature, there are no clear boundaries between different ecosystems. You can always point to a particular ecosystem, but it is not possible to single out discrete boundaries if they are not represented by various landscape factors (cliffs, rivers, various hillsides, rock outcrops, etc.), it is not possible, there are always smooth transitions from one ecosystems to another. This is due to a relatively smooth change in the gradient of environmental factors (humidity, temperature, humidity, etc.). Sometimes transitions from one ecosystem to another can actually be an independent ecosystem. Usually communities that form at the junction of different ecosystems are called ecotones. The term "ecotone" was introduced by F. Clements in 1905.

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Different ecosystems exist in the same biotope over time. The change from one ecosystem to another can take both rather long and relatively short (several years) periods of time. The duration of the existence of ecosystems in this case is determined by the stage of succession. A change in ecosystems in a biotope can also be caused by catastrophic processes, but in this case, the biotope itself changes significantly, and such a change is not usually called a succession (with some exceptions, when a catastrophe, for example, a fire, is a natural stage of a cyclic succession). Different ecosystems exist in the same biotope over time. The change from one ecosystem to another can take both rather long and relatively short (several years) periods of time. The duration of the existence of ecosystems in this case is determined by the stage of succession. A change in ecosystems in a biotope can also be caused by catastrophic processes, but in this case, the biotope itself changes significantly, and such a change is not usually called a succession (with some exceptions, when a catastrophe, for example, a fire, is a natural stage of a cyclic succession).

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Succession is a sequential, natural replacement of some communities by others in a certain area of ​​the territory, due to internal factors of ecosystem development. Each previous community predetermines the conditions for the existence of the next and its own disappearance. This is due to the fact that in ecosystems that are transitional in succession, there is an accumulation of matter and energy, which they are no longer able to include in the cycle, the transformation of the biotope, changes in the microclimate and other factors, and thus a material and energy base is created, as well as the environmental conditions necessary for the formation of subsequent communities. However, there is another model that explains the mechanism of succession as follows: the species of each previous community are replaced only by successive competition, inhibiting and "resisting" the introduction of subsequent species. However, this theory considers only the competitive relationship between species, not describing the whole picture of the ecosystem as a whole. Of course, such processes are going on, but the competitive displacement of the previous species is possible precisely because of their transformation of the biotope. Thus, both models describe different aspects of the process and are correct at the same time. Succession is a sequential, natural replacement of some communities by others in a certain area of ​​the territory, due to internal factors of ecosystem development. Each previous community predetermines the conditions for the existence of the next and its own disappearance. This is due to the fact that in ecosystems that are transitional in succession, there is an accumulation of matter and energy, which they are no longer able to include in the cycle, the transformation of the biotope, changes in the microclimate and other factors, and thus a material and energy base is created, as well as the environmental conditions necessary for the formation of subsequent communities. However, there is another model that explains the mechanism of succession as follows: the species of each previous community are replaced only by successive competition, inhibiting and "resisting" the introduction of subsequent species. However, this theory considers only the competitive relationship between species, not describing the whole picture of the ecosystem as a whole. Of course, such processes are going on, but the competitive displacement of the previous species is possible precisely because of their transformation of the biotope. Thus, both models describe different aspects of the process and are correct at the same time.

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Succession is autotrophic and heterotrophic. At the early stages of the autotrophic succession sequence, the P / R ratio is much greater than unity, since usually primary communities have high productivity, but the structure of the ecosystem has not yet been fully formed, and there is no way to utilize this biomass. Consistently, with the complication of the communities, with the complication of the ecosystem structure, the costs of respiration (R) grow, as more and more heterotrophs appear responsible for the redistribution of material-energy flows, the P / R ratio tends to unity and is in fact the same for the terminal community (ecosystem ). Heterotrophic succession has the opposite characteristics: in it, the P / R ratio in the early stages is much less than unity and gradually increases as we move through the succession stages. Succession is autotrophic and heterotrophic. At the early stages of the autotrophic succession sequence, the P / R ratio is much greater than unity, since usually primary communities have high productivity, but the structure of the ecosystem has not yet been fully formed, and there is no way to utilize this biomass. Consistently, with the complication of the communities, with the complication of the ecosystem structure, the costs of respiration (R) grow, as more and more heterotrophs appear responsible for the redistribution of material-energy flows, the P / R ratio tends to unity and is in fact the same for the terminal community (ecosystem ). Heterotrophic succession has the opposite characteristics: in it, the P / R ratio in the early stages is much less than unity and gradually increases as we move through the succession stages.

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The issue of ranking ecosystems is rather complicated. The identification of minimal ecosystems (biogeocenoses) and the ecosystem of the highest rank - the biosphere - is beyond doubt. Intermediate allocations are rather complicated, since the complexity of the psychological aspect does not always unambiguously allow determining the boundaries of ecosystems. In geoecology (and landscape science), there is the following ranking: facies - tract (ecosystem) - landscape - geographic area - geographic area - biome - biosphere. In ecology, there is a similar ranking, however, it is usually believed that it is correct to single out only one intermediate ecosystem - the biome. The issue of ranking ecosystems is rather complicated. The identification of minimal ecosystems (biogeocenoses) and the ecosystem of the highest rank - the biosphere - is beyond doubt. Intermediate allocations are rather complicated, since the complexity of the psychological aspect does not always unambiguously allow determining the boundaries of ecosystems. In geoecology (and landscape science), there is the following ranking: facies - tract (ecosystem) - landscape - geographic area - geographic area - biome - biosphere. In ecology, there is a similar ranking, however, it is usually believed that it is correct to single out only one intermediate ecosystem - the biome.

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Biome is a large system-geographical (ecosystem) subdivision within the natural-climatic zone (Reimers N.F.). According to R. H. Whittaker, a group of ecosystems of a given continent that have a similar structure or physiognomy of vegetation and the general nature of environmental conditions. This definition is somewhat incorrect, since there is a link to a specific continent, and some biomes are present on different continents, for example, a tundra biome or a steppe biome. Biome is a large system-geographical (ecosystem) subdivision within the natural-climatic zone (Reimers N.F.). According to R. H. Whittaker - a group of ecosystems of a given continent, which have a similar structure or physiognomy of vegetation and the general nature of environmental conditions. This definition is somewhat incorrect, since there is a link to a specific continent, and some biomes are present on different continents, for example, a tundra biome or a steppe biome. At the moment, the most generally accepted definition sounds like this: "Biome is a set of ecosystems with a similar type of vegetation located in the same natural and climatic zone" (Akimova T.A., Khaskin V.V.). What these definitions have in common is that in any case, a biome is a set of ecosystems of one natural and climatic zone.

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An ecosystem is a functional unity of living organisms and their habitat. The main characteristics ecosystem - its dimensionlessness and ranklessness. The replacement of some biocenoses with others over a long period of time is called succession. The succession that occurs on the newly formed substrate is called primary. A succession in an area already occupied by vegetation is called secondary.

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The unit of classification of ecosystems is the biome - natural area or an area with certain climatic conditions and the corresponding set dominant species plants and animals. A special ecosystem - biogeocenosis - an area of ​​the earth's surface with homogeneous natural phenomena. The constituent parts of the biogeocenosis are climatopes, edaphotop, hydrotope (biotope), as well as phytocenosis, zoocenosis, and microbocenosis (biocenosis).

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Ecosystems are the main structural units of the biosphere An ecological system, or ecosystem, is the main functional unit in ecology, since it includes organisms and an inanimate environment - components that mutually affect the properties of each other, and the necessary conditions for maintaining life in the form that exists on Earth. The term ecosystem was first proposed in 1935 by the English ecologist A. Tensley.

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In order to obtain food products, a person artificially creates agroecosystems. They differ from natural ones in low resistance and stability, but in higher productivity.

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Thus, an ecosystem is understood as a set of living organisms (communities) and their habitat, which, due to the circulation of substances, form a stable system of life. Communities of organisms are connected with the inorganic environment by the closest material and energy ties. Plants can exist only due to the constant supply of carbon dioxide, water, oxygen, and mineral salts. Heterotrophs live off autotrophs, but need the supply of inorganic compounds such as oxygen and water.

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In any particular habitat, the reserves of inorganic compounds necessary to maintain the vital activity of the organisms inhabiting it would not last long if these reserves were not renewed. The return of nutrients to the environment occurs both during the life of organisms (as a result of respiration, excretion, defecation), and after their death, as a result of decomposition of corpses and plant debris. Consequently, the community forms a certain system with the inorganic environment, in which the flow of atoms, caused by the vital activity of organisms, tends to close into a cycle.

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In the domestic literature, the term "biogeocenosis" is widely used, proposed in 1940 by B. N Sukachev. By his definition, a biogeocenosis is “a set of homogeneous natural phenomena (atmosphere, rock, soil and hydrological conditions), which has a special specificity of interactions of these constituent components and a certain type of exchange of matter and energy between themselves and other natural phenomena, and is an internally contradictory dialectical unity that is in constant motion and development. "

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In biogeocenosis V.N. Sukachev distinguished two blocks: ecotope - a set of conditions of the abiotic environment and biocenosis - a set of all living organisms (Fig. 8.1). An ecotope is often considered as an abiotic environment not transformed by plants (the primary complex of factors of the physical and geographical environment), but a biotope as a set of elements of the abiotic environment, modified by the environment-forming activity of living organisms.

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There is an opinion that the term "biogeocenosis" to a much greater extent reflects the structural characteristics of the studied macrosystem, while the concept of "ecosystem" implies, first of all, its functional essence. In fact, there is no difference between these terms. It should be pointed out that the combination of a specific physicochemical environment (biotope) with a community of living organisms (biocenosis) forms an ecosystem: Ecosystem = Biotope + Biocenosis.

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The equilibrium (stable) state of the ecosystem is provided on the basis of the cycles of substances (see paragraph 1.5). All components of ecosystems are directly involved in these cycles. To maintain the cycle of substances in the ecosystem, it is necessary to have a stock of inorganic substances in an assimilable form and three functionally different environmental groups organisms: producers, consumers and decomposers.

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Producers are autotrophic organisms that are able to build their bodies at the expense of inorganic compounds (Fig. 8.2).

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Consumptions are heterotrophic organisms that consume organic matter from producers or other consumers and transform it into new forms. Reducers live off dead organic matter, converting it back into inorganic compounds. This classification is relative, since both consumers and producers themselves act partly as decomposers during life, releasing mineral metabolic products into the environment.

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In principle, the circulation of atoms can be maintained in the system without an intermediate link - consumers, due to the activities of the other two groups. However, such ecosystems are found rather as exceptions, for example, in those areas where communities formed only from microorganisms function. The role of consumers in nature is performed mainly by animals; their activity to maintain and accelerate the cyclic migration of atoms in ecosystems is complex and diverse.

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The scale of an ecosystem in nature is very different. The degree of closeness of the circulations of matter supported in them is also not the same, i.e. multiple involvement of the same elements in cycles. As separate ecosystems, one can consider, for example, a lichen cushion on a tree trunk, and a crumbling stump with its population, and a small temporary reservoir, meadow, forest, steppe, desert, the entire ocean and, finally, the entire surface of the Earth, occupied with life.

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In some types of ecosystems, the removal of matter outside them is so great that their stability is maintained mainly due to the inflow of the same amount of matter from the outside, while the internal circulation is ineffective. These are flowing water bodies, rivers, streams, areas on steep mountain slopes. Other ecosystems have a much more complete cycle of substances and are relatively autonomous (forests, meadows, lakes, etc.).

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An ecosystem is practically a closed system. This is the fundamental difference between ecosystems and communities and populations, which are open systems exchanging energy, substance and information with the environment. However, none of the Earth's ecosystems has a completely closed cycle, since the minimum exchange of mass with the habitat still occurs. An ecosystem is a set of interconnected energy consumers who perform work to maintain its non-equilibrium state relative to the habitat through the use of the flow of solar energy.

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In accordance with the hierarchy of communities, life on Earth also manifests itself in the hierarchy of the corresponding ecosystems. The ecosystem organization of life is one of necessary conditions her existence. As already noted, the reserves of biogenic elements necessary for the life of organisms on the Earth as a whole and in each specific area on its surface are not unlimited. Only a system of cycles could give these reserves the property of infinity, which is necessary for the continuation of life.

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Only functionally different groups of organisms can support and carry out the cycle. The functional and ecological diversity of living things and the organization of the flow of substances extracted from the environment into cycles is the most ancient property of life. From this point of view, the stable existence of many species in the ecosystem is achieved due to the constantly occurring natural disturbances of habitats in it, which allow new generations to occupy the newly freed space.

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Ecosystem concept The main object of the study of ecology is ecological systems, or ecosystems. The ecosystem occupies the next place after biocenosis in the system of levels of living nature. Speaking about biocenosis, we meant only living organisms. If we consider living organisms (biocenosis) in conjunction with environmental factors, then this is already an ecosystem. Thus, an ecosystem is a natural complex (bioinert system) formed by living organisms (biocenosis) and their habitat (for example, the atmosphere is inert, soil, a reservoir is bioinert, etc.), interconnected by the exchange of substances and energy.

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The term “ecosystem” generally accepted in ecology was introduced in 1935 by the English botanist A. Tensley. He believed that ecosystems, "from the point of view of an ecologist, are the main natural units on the surface of the earth", which include "not only a complex of organisms, but also the whole complex of physical factors that form what we call the biome environment, habitat factors in the very broad sense". Tensley emphasized that ecosystems are characterized by various kinds of metabolism, not only between organisms, but also between organic and inorganic matter. It is not only a complex of living organisms, but also a combination of physical factors.

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Ecosystem (ecological system) is the main functional unit of ecology, which is a unity of living organisms and their habitat, organized by energy flows and biological circulation of substances. This is a fundamental community of living things and their environment, any set of living organisms living together and their conditions of existence (Fig. 8).

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Rice. 8. Various ecosystems: a - pond in the middle zone (1 - phytoplankton; 2 - zooplankton; 3 - swimming beetles (larvae and adults); 4 - young carps; 5 - pikes; 6 - larvae of choronomids (dergunts mosquitoes); 7- bacteria; 8 - insects of coastal vegetation; b - meadows (I - abiotic substances, i.e. the main inorganic and organic components); II- producers (vegetation); III- macroconsumptions (animals): A - herbivores (filly, field mice, etc.); B - indirect or detritus-feeding consumers, or saprobes (soil invertebrates); C- "riding" predators (hawks); IV- decomposers (putrefactive bacteria and fungi)

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The concept of "ecosystem" can be applied to objects of varying degrees of complexity and size. An example of an ecosystem is a rainforest in a specific location and at a specific point in time, inhabited by thousands of species of plants, animals and microbes living together and associated with interactions between them. Ecosystems are natural formations such as the ocean, sea, lake, meadow, swamp. An ecosystem can be a hummock in a swamp and a rotting tree in a forest with organisms living on and in them, an anthill with ants. The largest ecosystem is planet Earth.

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ECOSYSTEM This is the unity of living organisms and their environment (Arthur George Tensley). Living organisms living together form a biocenosis - a natural community of animals, plants, fungi and microorganisms. Biotope is a set of environmental conditions that determine the existence of a given biocenosis.

Ecosystem structure

Desert biocenosis

Biocenosis of a mixed temperate forest

Marine biocenosis

Factors that determine the existence of living organisms in terrestrial ecosystems Amount of solar energy (illumination). The amount of moisture. Air temperature. Atmosphere pressure.

Factors determining the existence of living organisms in aquatic ecosystems Illumination. Water temperature. Salinity of water. Acidity of water (pH level). Water flow rate.

LINEARITY This is the vertical distribution of living organisms at different heights relative to the surface of the earth in terrestrial ecosystems or at different depths relative to the surface of the water in aquatic ecosystems.

The compensation level (depth) is the limiting depth of the reservoir at which the photosynthesis process is possible. The acidity index (pH) is the negative decimal logarithm of the concentration of hydrogen cations in the solution: 0 7 - alkaline medium (ammonia - pH = 11). Optimal spacing for most aquatic life: 6 Slide 15

Limiting factors These are factors that limit the existence of species of living organisms in a certain habitat: minimum manifestation of a factor (Liebig's law of minimum); maximum manifestation of the factor (Shelford maximum rule). The minimum and maximum are the limits of tolerance (endurance).

On the subject: methodological developments, presentations and notes

Natural history lesson "What is the soil" in the 5th grade of the correctional school

On the lesson "What is the soil", an earthworm comes to visit the children, he asks the children to find out what the soil consists of. Students perform small experiments, examine a lump of soil, find out its composition ...

 

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