An ecological system has been introduced. ecological system

An ecological system or ecosystem is considered by science as a large-scale interaction of living organisms with their non-living environment. They influence each other, and their cooperation allows life to be sustained. The concept of "ecosystem" is generalized, it does not have a physical size, as it includes the ocean and, and at the same time a small puddle and a flower. Ecosystems are very diverse, they depend on a large number of factors, such as climate, geological conditions and human activities.

General concept

To fully understand the term "ecosystem" consider it on the example of a forest. A forest is not just a large number of trees or shrubs, but a complex set of interconnected elements of living and non-living (earth, sunlight, air) nature. Living organisms include:

insects;
lichens;
bacteria;
mushrooms.

Each organism performs its clearly defined role, and the overall work of all living and non-living elements creates a balance for the smooth operation of the ecosystem. Every time a foreign factor or a new living being enters an ecosystem, there may be Negative consequences causing destruction and potential harm. The ecosystem can be destroyed as a result of human activity or natural disasters.

Ecosystem types

Depending on the scale of manifestation, there are three main types of ecosystems:

Macroecosystem. A large system made up of small systems. An example is the desert, or the ocean inhabited by thousands of species of marine animals and plants.
Mesoecosystem. Ecosystem of a small size (a pond, a forest area or a separate clearing).
Microecosystem. A small-sized ecosystem that mimics in miniature the nature of various ecosystems (aquarium, an animal corpse, a forest stump, a pool of water inhabited by microorganisms).

The uniqueness of ecosystems is that they do not have clearly defined boundaries. Most often they complement each other or are separated by deserts, oceans and seas.

Man plays a significant role in the life of ecosystems. In our time, to meet its own goals, mankind creates new and destroys existing ecological systems. Depending on the method of formation, ecosystems are also divided into two groups:

natural ecosystem. It is created as a result of the forces of nature, is able to independently recover and create a vicious circle of substances, from creation to decay.
Artificial or anthropogenic ecosystem. It consists of plants and animals that live in conditions created by human hands (field, pasture, reservoir, botanical garden).

One of the largest artificial ecosystems is the city. Man invented it for the convenience of his own existence and created artificial energy inflows in the form of gas and water pipelines, electricity and heating. However, an artificial ecosystem requires additional inflows of energy and substances from outside.

global ecosystem

The totality of all ecological systems makes up the global ecosystem -. It is the largest set of interaction between animate and inanimate nature on planet Earth. It is in balance due to the balance of a huge variety of ecosystems and a variety of species of living organisms. It is so huge that it covers:

earth's surface;
the upper part of the lithosphere;
the lower part of the atmosphere;
all bodies of water.

Thanks to the constant, the global ecosystem has maintained its vital activity for billions of years.

Ecosystem is the functional unity of living organisms and their environment. Main characteristics ecosystems - its dimensionlessness and lack of rank. The replacement of some biocenoses by others over a long period of time is called succession. Succession occurring on a newly formed substrate is called primary. Succession in an area already occupied by vegetation is called secondary.

The unit of classification of ecosystems is a biome - a natural zone or area with certain climatic conditions and a corresponding set of dominant plant and animal species.

Special ecosystem - biogeocenosis - site earth's surface with similar natural phenomena. The components of biogeocenosis are climatotope, edaphotope, hydrotope (biotope), as well as phytocenosis, zoocenosis and microbiocenosis (biocenosis).

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

Ecosystems are the main structural units of the biosphere

The ecological system, or ecosystem, is the basic functional unit in ecology, since it includes organisms and

inanimate environment - components that mutually influence each other's properties, and the necessary conditions for maintaining life in the form that exists on Earth. Term ecosystem was first proposed in 1935 by an English ecologist A. Tansley.

Thus, an ecosystem is understood as a set of living organisms (communities) and their habitat, which, thanks 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 only exist due to the constant supply of carbon dioxide, water, oxygen, and mineral salts. Heterotrophs live off autotrophs, but need such inorganic compounds like oxygen and water.

In any particular habitat, the reserves of inorganic compounds necessary to maintain the vital activity of the organisms inhabiting it would suffice for a short time if these reserves were not renewed. The return of biogenic elements 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 the decomposition of corpses and plant residues.

Consequently, the community forms a certain system with the inorganic medium, in which the flow of atoms, caused by the vital activity of organisms, tends to be closed in a cycle.

Rice. 1. The structure of biogeocenosis and the scheme of interaction between the components

In the domestic literature, the term "biogeocenosis", proposed in 1940, is widely used. B. H Sukachev. According to his definition, 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 them and other natural phenomena and is an internally contradictory dialectical unity, which is in in constant motion, development".

In biogeocenosis V.N. Sukachev singled out two blocks: ecotope— set of conditions abiotic environment And biocenosis- the totality of all living organisms (Fig. 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), and a biotope is considered as a set of elements of the abiotic environment modified by the environment-forming activity of living organisms.

There is an opinion that the term "biogeocenosis" to a much greater extent reflects structural characteristics of the macrosystem under study, while the concept of "ecosystem" includes, 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 physical and chemical environment (biotope) with a community of living organisms (biocenosis) forms an ecosystem:

Ecosystem = Biotope + Biocenosis.

The equilibrium (stable) state of the ecosystem is ensured on the basis of the circulation of substances. All components of ecosystems are directly involved in these cycles.

To maintain the circulation of substances in an ecosystem, it is necessary to have a stock of inorganic substances in an assimilated form and three functionally different ecological groups of organisms: producers, consumers, and decomposers.

Producers autotrophic organisms appear, capable of building their bodies at the expense of inorganic compounds (Fig. 2).

Rice. 2. Producers

Consumers heterotrophic organisms that consume organic matter producers or other consumers and transforming it into new forms.

decomposers live at the expense of dead organic matter, translating it again into inorganic compounds. This classification is relative, since both consumers and producers themselves partially act as decomposers during their life, releasing mineral metabolic products into the environment.

In principle, the circulation of atoms can be maintained in the system without an intermediate link - consumers, due to the activity of two other 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 in maintaining and accelerating the cyclic migration of atoms in ecosystems is complex and diverse.

The scale of the ecosystem in nature is very different. The degree of closure of the cycles of matter maintained in them is also not the same, i.e. repeated involvement of the same elements in cycles. As separate ecosystems, one can consider, for example, a pillow of lichens on a tree trunk, and a collapsing 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 by life.

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

An ecosystem is an almost closed system. This is the fundamental difference between ecosystems and communities and populations, which are open systems, exchanging energy, matter and information with the environment.

However, not a single ecosystem of the Earth has a completely closed cycle, since the minimum exchange of mass with the environment still occurs.

The ecosystem is a set of interconnected energy consumers doing work to maintain its non-equilibrium state relative to the environment through the use of solar energy flow.

In accordance with the hierarchy of communities, life on Earth is also manifested in the hierarchy of the corresponding ecosystems. The ecosystem organization of life is one of the necessary conditions for its 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, necessary for the continuation of life.

Only functionally different groups of organisms can support and carry out the cycle. Functional and ecological diversity of living beings and organization of the flow of extracted from environment substances in cycles - the most ancient property of life.

From this point of view, the sustainable existence of many species in an ecosystem is achieved through natural habitat disturbances that constantly occur in it, allowing new generations to occupy the newly vacated space.

Ecosystem concept

The main object of study of ecology are ecological systems, or ecosystems. The ecosystem occupies the next place after the biocenosis in the system of levels of wildlife. Speaking of biocenosis, we had in mind 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 (bio-inert system) formed by living organisms (biocenosis) and their habitat (for example, the atmosphere is inert, the soil, the reservoir is bio-inert, etc.), interconnected by the metabolism and energy.

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 basic 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 environment of a biome - habitat factors in in the broadest 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.

Ecosystem (ecological system)- the main functional unit of ecology, which is a unity of living organisms and their habitat, organized by energy flows and the biological cycle of substances. This is a fundamental commonality of the living and its habitat, any set of living organisms living together and the conditions for their existence (Fig. 3).

Rice. 3. Various ecosystems: a - ponds of the middle belt (1 - phytoplankton; 2 - zooplankton; 3 - swimming beetles (larvae and adults); 4 - young carps; 5 - pikes; 6 - larvae of horonomids (twitching 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 - macroconsumers (animals): A - herbivores (fillies, field mice, etc.); B - indirect or detritus-eating consumers, or saprobes (soil invertebrates); C - "riding" predators (hawks); IV - decomposers (putrefactive bacteria and fungi)

The concept of "ecosystem" can be applied to objects varying degrees complexity and magnitude. An example of an ecosystem would be a tropical forest at a particular place and time, inhabited by thousands of species of plants, animals, and microbes living together and bound by the interactions that take place between them. Ecosystems are such natural formations 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 them and in them, an anthill with ants. The largest ecosystem is the planet Earth.

Each ecosystem can be characterized by certain boundaries (a spruce forest ecosystem, a lowland swamp ecosystem). However, the very concept of "ecosystem" is rankless. It has a sign of dimensionlessness, it is not characterized by territorial restrictions. Ecosystems are usually delimited by elements of the abiotic environment, such as topography, species diversity, physicochemical and trophic conditions, etc. The size of ecosystems cannot be expressed in terms of physical units measurements (area, length, volume, etc.). It is expressed by a systemic measure that takes into account the processes of metabolism and energy. Therefore, an ecosystem is usually understood as a set of components of the biotic (living organisms) and abiotic environment, during the interaction of which a more or less complete biotic cycle occurs, in which producers, consumers and decomposers participate. The term "ecosystem" is also used in relation to artificial formations, for example, a park ecosystem, an agricultural ecosystem (agroecosystem).

Ecosystems can be divided into microecosystems(tree in the forest, coastal thickets of aquatic plants), mesoecosystems(swamp, pine forest, rye field) and macroecosystems(ocean, sea, desert).

On the balance in ecosystems

Equilibrium ecosystems are those that "control" the concentrations of nutrients, maintaining their balance with solid phases. The solid phases (the remains of living organisms) are the products of the vital activity of the biota. Equilibrium will be those communities and populations that are part of an equilibrium ecosystem. This type of biological balance is called mobile, since the processes of dying off are continuously compensated by the appearance of new organisms.

Equilibrium ecosystems obey Le Chatelier's principle of sustainability. Consequently, these ecosystems have homeostasis, in other words, they are able to minimize external impact while maintaining internal balance. Ecosystem resilience is not achieved by displacement chemical equilibria, but by changing the rates of synthesis and decomposition of biogens.

Of particular interest is the way to maintain the sustainability of ecosystems, based on the involvement in the biological cycle of organic substances previously produced by the ecosystem and deposited "in reserve" - wood and mortmass (peat, humus, litter). In this case, the wood serves as a kind of individual material wealth, while the mortmass serves as a collective wealth that belongs to the ecosystem as a whole. This “material wealth” increases the margin of ecosystem resilience, ensuring their survival in the face of adverse climate change, natural disasters, etc.

The stability of an ecosystem is the greater, the larger it is in size and the richer and more diverse its species and population composition.

ecosystems different type use various variants of individual and collective ways of storing stability with a different ratio of individual and collective material wealth.

Thus, the main function of the totality of living beings (communities) included in the ecosystem is to ensure an equilibrium (sustainable) state of the ecosystem based on a closed circulation of substances.

The ecosystem refers to the key concepts of ecology. The word itself stands for "ecological system". The term was proposed by ecologist A. Tensley in 1935. Ecosystem combines several concepts:

Biocenosis - a community of living organisms
Biotope - the habitat of these organisms
Types of relationships of organisms in a given habitat
The exchange of substances that occurs between these organisms in a given biotope.

That is, in fact, an ecosystem is a combination of components of animate and inanimate nature, between which energy is exchanged. And thanks to this exchange, it is possible to create the conditions necessary to sustain life. The basis of any ecosystem on our planet is the energy of sunlight.

To classify ecosystems, scientists have chosen one feature - the habitat. So it is more convenient to single out individual ecosystems, since it is the area that determines the climatic, bioenergetic and biological features. Consider the types of ecosystems.

natural ecosystems are formed on earth spontaneously, with the participation of the forces of nature. For example, natural lakes, rivers, deserts, mountains, forests, etc.

Agroecosystems- this is one of the types of artificial ecosystems created by man. They are distinguished by weak links between components, a smaller species composition of organisms, artificiality of interchange, but at the same time, agroecosystems are the most productive. Their man creates for the sake of obtaining agricultural products. Examples of agro-ecosystems: arable lands, pastures, orchards, orchards, fields, planted forests, artificial ponds...

Forest ecosystems are a community of living organisms that live in trees. On our planet, a third of the land is occupied by forests. Almost half of them are tropical. The rest are coniferous, deciduous, mixed, broad-leaved.

Separate tiers are distinguished in the structure of the forest ecosystem. Depending on the height of the tier, the composition of living organisms changes.

Plants are the main ones in the forest ecosystem, and the main one is one (rarely several) plant species. All other living organisms are either consumers or destroyers, in one way or another affecting the metabolism and energy...

Plants and animals are only an integral part of any ecosystem. Yes, animals are the most important natural resource, without which the existence of an ecosystem is impossible. They are more mobile than plants. And, despite the fact that fauna loses to flora in terms of species diversity, it is animals that ensure the stability of the ecosystem by actively participating in the metabolism and energy.

At the same time, all animals form the genetic fund of the planet, living only in those ecological niches where all conditions for survival and reproduction are created for them.

Plants are fundamental to the existence of any ecosystem. It is they who are most often decomposers - that is, organisms that process solar energy. And the sun, as noted above, is the basis for the existence of life forms on Earth.

If we consider representatives of flora and fauna separately, then each animal and plant is a microecosystem at one stage or another of existence. For example, a tree trunk as it develops is one whole ecosystem. The trunk of a fallen tree is another ecosystem. It is the same with animals: an embryo in the stage of reproduction can be considered a microecosystem ...

Aquatic ecosystems are systems adapted to life in water. It is water that determines the uniqueness of the community of living organisms that live in it. Diversity of animal and plant species, condition, stability of the aquatic ecosystem depends on five factors:

Salinity of water
The percentage of oxygen it contains
Transparency of water in a reservoir
Water temperatures
Availability of nutrients.

It is customary to divide all aquatic ecosystems into two large classes: freshwater and marine. Marine occupy more than 70% of the earth's surface. These are oceans, seas, salt lakes. There are fewer freshwater: most of the rivers, lakes, swamps, ponds and other smaller reservoirs ...

The stability of an ecosystem is the ability of a given system to withstand changes in external factors and maintain its structure.

In ecology, it is customary to distinguish two types of sustainability of ES:

resistive- this is a type of stability in which an ecosystem is able to maintain its structure and functionality unchanged, despite changes in external conditions.
elastic- this type of stability is inherent in those ecosystems that can restore their structure after changing conditions or even after destruction. For example, when a forest recovers after a fire, it is precisely the elastic stability of the ecosystem that is spoken of.
Human ecosystem

In the human ecosystem, humans will be the dominant species. It is more convenient to divide such ecosystems into areas:

An ecosystem is a stable system of components of living and non-living origin, in which both objects of inanimate nature and objects of living nature participate: plants, animals and humans. Every person, regardless of the place of birth and residence (whether it be a noisy metropolis or a village, an island or a large land, etc.) is part of an ecosystem....

At present, human influence on any ecosystem is felt everywhere. For their own purposes, man either destroys or improves the ecosystems of our planet.

So, wasteful attitude to the land, deforestation, drainage of swamps are attributed to the destructive impact of man. And vice versa, the creation of reserves, the restoration of animal populations contribute to the restoration of the Earth's ecological balance and is a creative human influence on ecosystems...

The main difference between such ecosystems is the way they are formed.

natural, or natural ecosystems are created with the participation of the forces of nature. A person either does not influence them at all, or there is an influence, but insignificant. The largest natural ecosystem is our planet.

artificial Ecosystems are also called anthropogenic. They are created by man for the sake of obtaining "benefits" in the form of food, clean air, and other products necessary for survival. Examples: garden, vegetable garden, farm, reservoir, greenhouse, aquarium. Even spaceship can be considered as an example of an anthropogenic ecosystem.

The main differences between artificial ecosystems and natural ones.

An ecosystem is a biological system that consists of a set of living organisms, their habitat, as well as a system of connections that exchange energy between them. Currently, this term is the main concept of ecology.

Structure

are being studied relatively recently. Scientists distinguish two main components in it - biotic and abiotic. The first is divided into heterotrophic (includes organisms that receive energy as a result of the oxidation of organic matter - consumers and decomposers) and receive primary energy for photosynthesis and chemosynthesis, i.e. producers).

The only and most important source of energy necessary for the existence of the entire ecosystem are producers that absorb the energy of the sun, heat and chemical bonds. Therefore, autotrophs are representatives of the first of the entire ecosystem. The second, third and fourth levels are formed by consumers. They close with reducers capable of converting inanimate organic matter into an abiotic component.

The properties of an ecosystem, which you can briefly read about in this article, imply the possibility of natural development and renewal.

The main components of the ecosystem

The structure and properties of an ecosystem are the main concepts that ecology deals with. It is customary to highlight the following indicators:

Climatic regime, ambient temperature, as well as humidity and lighting conditions;

Organic substances that bind the abiotic and biotic components in the cycle of substances;

Inorganic compounds included in the energy cycle;

Producers are organisms that create primary products;

Phagotrophs - heterotrophs that feed on other organisms or large particles of organic matter;

Saprotrophs are heterotrophs capable of destroying dead organic matter, mineralizing it and returning it to the cycle.

The totality of the last three components forms the biomass of the ecosystem.

The ecosystem, the properties and which are studied in ecology, functions due to the blocks of organisms:

Saprophages - feed on dead organic matter.
Biophages - eat other living organisms.

Ecosystem sustainability and biodiversity

The properties of an ecosystem are related to the diversity of species that live in it. The greater the biodiversity and complexity, the greater the resilience of the ecosystem.

Biodiversity is very important, as it makes it possible to form a large number of communities that differ in form, structure and function, and provides a real opportunity for their formation. Therefore, the higher the biodiversity, the greater the number of communities can live, and the greater the number of biogeochemical reactions can be carried out, while ensuring the complex existence of the biosphere.

Are they true the following judgments about the properties of an ecosystem? This concept is characterized by integrity, stability, self-regulation and self-reproducibility. Many scientific experiments and observations give an affirmative answer to this question.

Ecosystem productivity

During the study of productivity, concepts such as biomass and standing crops were put forward. The second term defines the mass of all organisms living on a unit area of water or land. But biomass is also the weight of these bodies, but in terms of energy or dry organic matter.

Biomass includes entire bodies (including dead tissues in animals and plants.) Biomass becomes necromass only when the entire organism dies.

Communities are the formation of biomass by producers, without exception, of energy that can be spent on breathing per unit area per unit of time.

Allocate gross and net primary production. The difference between the two is the cost of breathing.

The net productivity of the community is the rate of accumulation of organic matter, which is not consumed by heterotrophs, and, as a result, decomposers. It is customary to calculate for a year or a growing season.

The secondary productivity of a community is the rate at which consumers accumulate energy. The more consumers in the ecosystem, the more energy is processed.

Self-regulation

Ecosystem properties also include self-regulation, the effectiveness of which is regulated by the diversity of inhabitants and food relations between them. When the number of one of the primary consumers decreases, the predators move on to other species that used to be of secondary importance to them.

Long chains can intersect, thus creating the possibility of a variety of food relationships depending on the number of prey or plant yield. In the most favorable times, the number of species can be restored - thus, relations in the biogenocenosis are normalized.

Unreasonable human intervention in the ecosystem can have negative consequences. Twelve pairs of rabbits brought to Australia in forty years have multiplied to several hundred million individuals. This happened due to the insufficient number of predators that feed on them. As a result, furry animals destroy all vegetation on the mainland.

Biosphere

The biosphere is an ecosystem of the highest rank, uniting all ecosystems into one whole and providing the possibility of life on planet Earth.

How the global ecosystem is studied by the science of ecology. It is important to know how the processes that affect the life of all organisms as a whole are arranged.

The composition of the biosphere includes the following components:

- Hydrosphere is the water layer of the earth. It is mobile and penetrates everywhere. Water is a unique compound, which is one of the foundations of the life of any organism.

- Atmosphere- the lightest air bordering outer space. Thanks to it, there is an exchange of energy with external space;

- Lithosphere- the solid shell of the Earth, consisting of igneous and sedimentary rocks.

- Pedosphere- the upper layer of the lithosphere, including the soil and the process of soil formation. It borders on all previous shells and closes all cycles of energy and matter in the biosphere.

The biosphere is not a closed system, since it is almost completely provided by solar energy.

artificial ecosystems

Artificial ecosystems are systems created as a result of human activity. This includes agrocenoses and natural economic systems.

The composition and basic properties of an ecosystem created by man differ little from the real one. It also has producers, consumers and decomposers. But there are differences in the redistribution of matter and energy flows.

Artificial ecosystems differ from natural ones in the following ways:

A much smaller number of species and a clear predominance of one or more of them.
Relatively low stability and strong dependence on all types of energy (including humans).
Short food chains due to low species diversity.
An open circulation of substances due to the removal of community products or crops by humans. At the same time, natural ecosystems, on the contrary, include as much of it as possible in the cycle.

The properties of an ecosystem created in an artificial environment are inferior to those of a natural one. If you do not support energy flows, then through certain time natural processes are restored.

forest ecosystem

The composition and properties of a forest ecosystem differ from other ecosystems. In this environment, much more precipitation falls than over the field, but most of it does not reach the surface of the earth and evaporates directly from the leaves.

The deciduous forest ecosystem is represented by several hundred plant species and several thousand animal species.

Plants growing in the forest are real competitors and fight for sunlight. The lower the tier, the more shade-tolerant species settled there.

The primary consumers are hares, rodents and birds and large herbivores. Everything nutrients, which are contained in the summer in the leaves of plants, in the fall they pass into branches and roots.

Caterpillars and bark beetles also belong to the primary consumers. Each food level is represented by a large number of species. The role of herbivorous insects is very important. They are pollinators and serve as a food source for the next level in the food chain.

fresh water ecosystem

The most favorable conditions for the life of living organisms are created in coastal zone reservoir. It is here that the water warms up best and contains the most oxygen. And it is here that a large number of plants, insects and small animals live.

The system of food relations in fresh water is very complex. Higher plants consume herbivorous fish, mollusks and insect larvae. The latter, in turn, are a source of food for crustaceans, fish and amphibians. Predatory fish feed on smaller species. Mammals also find food here.

But the remains of organic matter fall to the bottom of the reservoir. Bacteria develop on them, which are consumed by protozoa and filter clams.

Lecture 2. Ecological system

general characteristics ecosystems

Definition and concept of an ecosystem. The concept of an ecosystem is one of basic concepts in modern ecology. The term "ecosystem" was introduced by A. Tensley in 1935, later more than half a century after ecology as an independent branch of scientific knowledge (1866).

Ecosystem- this is the functional unity of living organisms and their environment.

Under ecosystem is understood as the totality of living organisms (communities) and their habitats, which, thanks to the circulation of substances, form a stable system of life

Consequently, the community forms a certain system with the inorganic medium, in which the flow of atoms, caused by the vital activity of organisms, tends to be closed in a cycle.

In the domestic literature, the term "biogeocenosis", proposed in 1940, is widely used. B. Nsukachev.

Rice. 1. The structure of biogeocenosis and the scheme of interaction between the components

In biogeocenosis V.N. Sukachev singled out two blocks: ecotope- a set of conditions of the abiotic environment and biocenosis- the totality of all living organisms (Fig..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), and a biotope is considered as a set of elements of the abiotic environment modified by the environment-forming activity of living organisms.

Ecosystem structure is shown quite well in the example biogeocenosis, all components of which are closely related to each other

The unity of the territory

The general flow of energy (from the Sun to autotrophs and from them to heterotrophs), the exchange of biogenic chemical elements,

seasonal fluctuations climatic conditions,

The number and mutual fitness of species at all levels of organization.

Types of ecosystems.

The most important from the point of view of the organization of ecosystems is their species structure.

An ecosystem is a complex object, in the study of which methods of system analysis are used. Classification of such complex systems should be carried out on various grounds, or signs of division into classes.

By spatial scale Ecosystems of various ranks are distinguished:

microecosystems,

mesoecosystems,

macroecosystems and

global ecosystem.

have the lowest rank microecosystems, examples of which are a small body of water, the corpse of an animal with organisms inhabiting it, or the trunk of a fallen tree in the stage of biological decomposition, a home aquarium and even a puddle or a drop of water, as long as they contain living organisms capable of cycling substances.

Ecosystems of intermediate rank are called meso-ecosystems(forest, pond, river)

macroecosystems have a large spatial scale and are associated with large geographical objects that make up a significant part of the earth's surface in size (for example, ocean, continent etc.).

The highest rank is global Ecosystem, equivalent to the Earth's biosphere as a whole. Thus, larger ecosystems include smaller ecosystems.

For the convenience of considering some features of interaction between society and nature within the framework of the discipline under study, according to the degree of anthropogenic impact on the natural environment, we will distinguish the following three types of ecosystems:

natural,

anthropogenic .

socio-natural

natural ecosystems, are natural ecosystems, the study of which does not take into account any anthropogenic impacts.

According to the nature of the environment communities of living organisms natural (natural) ecosystems are divided into ground And aquatic, among the latter, freshwater and marine ecosystems are sometimes distinguished.

The main ecological properties of ecosystems significantly depend on the difference in environmental conditions (geographical, hydrographic, climatic, soil, etc.). Therefore, these types natural ecosystems subdivided in turn into different types of ecosystems. In the class of terrestrial ecosystems, tundra, taiga, steppe, etc. are distinguished, and freshwater ecosystems are divided into lake, river, swamp, etc.

Anthropogenic ecosystems- artificial ecosystems, directly and purposefully created by man to meet his needs. It is convenient to divide them into technogenic and agroecosystems.

TO technogenic include ecosystems purposefully created to solve certain problems of environmental protection and nature management, for example, complex treatment facilities and complexes biological treatment Wastewater In many major cities peace.

Agroecosystems are created in almost all countries and are designed to dramatically increase land fertility and increase crop yields through chemicalization and the use of new agricultural production technologies.

Socio-natural ecosystems, which are formed not as a result of deliberate human activities, but arise indirectly due to the interaction of human society with the natural environment. The unconscious activity of a person, associated with the satisfaction of his constantly growing needs, leads to the fact that natural ecosystems in his environment are transformed (transformed) into socio-natural ecosystems, consisting of animate and inanimate nature and non-nature, i.e. culture.

A feature of the consideration of socio-natural ecosystems is the inclusion of a person in the ecosystem as bearer of culture . The need for such a socio-natural approach to the consideration of ecosystems in modern ecology is also due to the fact that a person in modern conditions has become geological transformative force, without taking into account which it is impossible to develop strategies for the sustainable development of civilization and rational environmental management.

Ecological systems of different levels are the main functional units of the biosphere.