How agroecosystems differ from natural ecosystems: concepts and comparative characteristics. Ecosystems: natural and artificial

Comparison of natural and simplified anthropogenic ecosystems (after Miller, 1993)

The main goal of the created agricultural systems is the rational use of those biological resources, which are directly involved in the sphere of human activity - sources of food products, technological raw materials, medicines.

Agroecosystems are created by humans to obtain high yields - pure production of autotrophs.

Summarizing everything that has already been said about agroecosystems, we emphasize their following main differences from natural ones (Table 2).

1. In agroecosystems, the diversity of species is sharply reduced:

§ a decrease in the species of cultivated plants also reduces the visible diversity of the animal population of the biocenosis;

§ the species diversity of animals bred by humans is negligible compared to nature;

§ cultivated pastures (with grass crops) are similar in species diversity to agricultural fields.

2. Species of plants and animals cultivated by humans “evolve” due to artificial selection and are uncompetitive in the fight against wild species without human support.

3. Agroecosystems receive additional energy subsidized by humans, in addition to solar energy.

4. Pure products (harvest) are removed from the ecosystem and do not enter the food chain of the biocenosis, but its partial use by pests, losses during harvesting, which can also enter natural trophic chains. They are suppressed by humans in every possible way.

5. Ecosystems of fields, gardens, pastures, vegetable gardens and other agrocenoses are simplified systems supported by humans in the early stages of succession, and they are just as unstable and incapable of self-regulation as natural pioneer communities, and therefore cannot exist without human support.

table 2

Comparative characteristics of natural ecosystems and agroecosystems.

Ecological communities. Species and spatial structure of ecosystems.

An ecosystem is a biological system consisting of a community of living organisms (biocenosis), their habitat (biotope), and a system of connections that exchanges matter and energy between them.
A biocenosis is an organized group of interconnected populations of plants, animals, fungi and microorganisms living together under the same environmental conditions.
The biosphere is the shell of the Earth populated by living organisms, under their influence and occupied by the products of their vital activity; “film of life”; global ecosystem of the Earth.

2. Fill out the table.

Ecological communities

3. What characteristics underlie the classification of ecosystems?
When classifying terrestrial ecosystems, the characteristics of plant communities (which form the basis of ecosystems) and climatic (zonal) characteristics are usually used. Thus, certain types of ecosystems are distinguished, for example, lichen tundra, moss tundra, coniferous forest (spruce, pine), deciduous forest (birch forest), rain forest (tropical), steppe, shrubs (willow), grassy swamp, sphagnum swamp. Often, the classification of natural ecosystems is based on the characteristic ecological features of habitats, distinguishing communities of sea coasts or shelves, lakes or ponds, floodplain or upland meadows, rocky or sandy deserts, mountain forests, estuaries (the mouths of large rivers), etc.

4. Fill out the table.

Comparative characteristics of natural and artificial ecosystems

5. What is the significance of agrobiocenoses in human life?
Agrobiocenoses provide humanity with about 90% of food energy.

6. List the main activities being undertaken to improve the condition of urban ecological systems.
Greening the city: creating parks, squares, green areas, flower beds, flower beds, green areas around industrial enterprises. Compliance with the principles of uniformity and continuity in the placement of green spaces.

7. What is meant by community structure?
This is the ratio of different groups of organisms that differ in systematic position, in the role they play in the processes of transfer of energy and matter, in the place occupied in space, in the food or trophic network, or in other characteristics that are essential for understanding the patterns of functioning of natural ecosystems .

8. Fill out the table.

Community structure

Food connections, circulation of substances and energy conversion in ecosystems

1. Define the concepts.
A food chain is a series of species of plants, animals, fungi and microorganisms that are connected to each other by the relationship: food - consumer (a sequence of organisms in which a gradual transfer of matter and energy occurs from source to consumer).
A food web is a diagram of all food (trophic) connections between species of a community.
Trophic level- this is a collection of organisms that, depending on the method of their nutrition and the type of food, constitute a certain link in the food chain.

2. How do pasture chains differ from detritus chains?
In the grazing chain, energy flows from plants through herbivores to carnivores. The flow of energy coming from dead organic matter and passing through a system of decomposers is called the detrital chain.

3. Fill out the table.

Trophic levels of an ecosystem

4. What is the essence of the cycle of substances in an ecosystem?
Energy cannot be transferred in a vicious circle; it is consumed, turning into the energy of chemical bonds and heat. The substance can be transmitted in closed cycles, circulating repeatedly between living organisms and the environment.

5. Do practical work.
1. Drawing up diagrams of the transfer of substances and energy (food chain)
Name the organisms that should be in the missing places in the following food chains.

2. From the proposed list of organisms, make up detrital and pasture trophic networks: grass, berry bush, fly, tit, grass snake, hare, wolf, decay bacteria, mosquito, grasshopper.

6. What limits the length of each food chain in an ecosystem?
Living organisms, eating representatives of the previous level, receive the energy stored in its cells and tissues. It spends a significant part of this energy (up to 90%) on movement, breathing, heating the body, etc. and only 10% accumulates in its body in the form of proteins (muscles) and fats (adipose tissue). Thus, only 10% of the energy accumulated by the previous level is transferred to the next level. This is why food chains cannot be very long.

7. What is meant by ecological pyramids? What types distinguish them?
It is a way of graphically displaying the relationship of different trophic levels in an ecosystem. There can be three types:
1) population pyramid - reflects the number of organisms at each trophic level;
2) biomass pyramid - reflects the biomass of each trophic level;
3) energy pyramid - shows the amount of energy that has passed through each trophic level over a certain period of time.

8. Can an ecological pyramid be upside down? Support your answer with a specific example.
If the reproduction rate of the prey population is high, then even with low biomass such a population can be a sufficient source of food for predators that have a higher biomass but a low reproduction rate. For this reason, population or biomass pyramids may be inverted, i.e. lower trophic levels may have less density and biomass than higher ones.
For example:
1) Many insects can live and feed on one tree.
2) The inverted pyramid of biomass is characteristic of marine ecosystems, where the primary producers (phytoplanktonic algae) divide very quickly, and their consumers (zooplanktonic crustaceans) are much larger, but reproduce much more slowly. Marine vertebrates have even greater mass and long reproductive cycles.

9. Solve environmental problems.
Task 1. Calculate the amount of plankton (in kg) required for a dolphin weighing 350 kg to grow in the sea.

Solution. A dolphin, feeding on predatory fish, accumulated only 10% of the total mass of food in its body; knowing that it weighs 350 kg, let’s calculate the proportion.
350kg – 10%,
X – 100%.
Let's find what X is equal to. X=3500 kg. (predatory fish). This weight is only 10% of the mass of the non-predatory fish that they fed on. Let's make the proportion again.
3500kg – 10%
X – 100%
X=35,000 kg (mass of non-predatory fish)
How much plankton did they have to eat in order to have that weight? Let's make a proportion.
35,000 kg.- 10%
X =100%
X = 350,000 kg
Answer: In order for a dolphin weighing 350 kg to grow, 350,000 kg of plankton are needed.

Task 2. As a result of the study, it turned out that after the extermination of birds of prey, the number of game birds, destroyed by them earlier, first grows rapidly, but then rapidly falls. How can this pattern be explained?

Answer: To answer this question, it is necessary to take into account the following provisions: an “uncontrolled” increase in the number of game birds leads to a depletion of the food supply, a weakening of the resistance of bird organisms to diseases, the rapid spread of infection, degeneration, a decrease in fertility and mass death of birds from disease.

Task 3. Daphnia feeding on them was placed in a vessel with planktonic algae. After this, algae abundance decreased, but algal biomass production (measured by the rate of cell division) increased. What are the possible explanations for this phenomenon?

Answer: Daphnia, as a result of metabolism, release substances that accelerate the growth of algae (their food supply), thereby achieving eco-balance.

Reasons for sustainability and change of ecosystems

1. Define the concepts.
Succession is a natural and consistent process of change of communities in a certain area, caused by the interaction of living organisms with each other and the abiotic environment surrounding them.
Common breath of the community– in ecology, total energy consumption, i.e., the total production of autotrophs in energy terms exactly corresponds to the energy consumption used to ensure the vital activity of its constituent organisms.

2. What is meant by equilibrium in a community, and what significance does it have for its existence as a whole?
The biomass of organisms in ideal succession remains constant, and the system itself remains in equilibrium. If the “total respiration” is less than the gross primary production, the accumulation of organic matter will occur in the ecosystem; if it is more, it will decrease. Both will lead to community change. If there is an excess of a resource, there will always be species that can master it; if there is a shortage, some species will go extinct. Such changes constitute the essence of ecological succession. The main feature of this process is that changes in the community always occur in the direction of an equilibrium state. Each stage of succession is a community with a predominance of certain species and life forms. They replace each other until a state of stable equilibrium occurs.

3. Fill out the table.

Types of successions

4. What determines the duration of succession?
The duration of succession is largely determined by the structure of the community.
Secondary successions proceed much faster. This is explained by the fact that the primary community leaves behind a sufficient amount of nutrients and developed soil, which creates conditions for the accelerated growth and development of new settlers.

5. What are the advantages of a mature community over a young community?
A mature community, with its greater diversity and abundance of organisms, developed trophic structure, and balanced energy flows, is able to withstand changes in physical factors (e.g., temperature, humidity) and even some types of chemical pollution to a much greater extent than a young community.

6. What is the importance of being able to control the processes occurring in a community?
A person can reap a rich harvest in the form of pure products by artificially maintaining a community in the early stages of succession. On the other hand, the stability of a mature community, its ability to withstand the effects of physical factors (and even manage them) is a very important and highly desirable property. At the same time, various disturbances in mature ecosystems can lead to various environmental disturbances. The transformation of the biosphere into one vast carpet of arable land is fraught with great danger. Therefore, it is necessary to learn how to properly manage processes in the community in order to prevent an environmental disaster.

Lecture No. 5. Artificial ecosystems

5.1 Natural and artificial ecosystems

In the biosphere, in addition to natural biogeocenoses and ecosystems, there are communities artificially created by human economic activity - anthropogenic ecosystems.

Natural ecosystems are distinguished by significant species diversity, exist for a long time, they are capable of self-regulation, and have great stability and resilience. The biomass and nutrients created in them remain and are used within the biocenoses, enriching their resources.

Artificial ecosystems - agrocenoses (fields of wheat, potatoes, vegetable gardens, farms with adjacent pastures, fish ponds, etc.) make up a small part of the land surface, but provide about 90% of food energy.

The development of agriculture since ancient times has been accompanied by the complete destruction of vegetation cover over large areas in order to make room for a small number of species selected by humans that are most suitable for food.

However, initially human activity in agricultural society fit into the biochemical cycle and did not change the flow of energy in the biosphere. In modern agricultural production, the use of synthesized energy during mechanical cultivation of the land, the use of fertilizers and pesticides has sharply increased. This disrupts the overall energy balance of the biosphere, which can lead to unpredictable consequences.

Comparison of natural and simplified anthropogenic ecosystems

(after Miller, 1993)

5.2 Artificial ecosystems

5.2.1 Agroecosystems

Agroecosystem(from the Greek agros - field) - a biotic community created and regularly maintained by humans in order to obtain agricultural products. Usually includes a set of organisms living on agricultural lands.

Agroecosystems include fields, orchards, vegetable gardens, vineyards, large livestock complexes with adjacent artificial pastures.

A characteristic feature of agroecosystems is low ecological reliability, but high productivity of one (several) species or varieties of cultivated plants or animals. Their main difference from natural ecosystems is their simplified structure and depleted species composition.

Agroecosystems are different from natural ecosystems a number of features:

1. The diversity of living organisms in them is sharply reduced to obtain the highest possible production.

In a rye or wheat field, in addition to the cereal monoculture, you can find only a few types of weeds. In a natural meadow, biological diversity is much higher, but biological productivity is many times lower than in a sown field.

Artificial regulation of pest numbers is, for the most part, a necessary condition for maintaining agroecosystems. Therefore, in agricultural practice, powerful means are used to suppress the number of undesirable species: pesticides, herbicides, etc. The environmental consequences of these actions lead, however, to a number of undesirable effects other than those for which they are used.

2. Species of agricultural plants and animals in agroecosystems are obtained as a result of artificial rather than natural selection, and cannot withstand the struggle for existence with wild species without human support.

As a result, there is a sharp narrowing of the genetic base of agricultural crops, which are extremely sensitive to the massive proliferation of pests and diseases.

3. Agroecosystems are more open; matter and energy are removed from them with crops, livestock products, and also as a result of soil destruction.

In natural biocenoses, the primary production of plants is consumed in numerous food chains and again returns to the biological cycle system in the form of carbon dioxide, water and mineral nutrition elements.

Due to the constant harvesting and disruption of soil formation processes, with long-term cultivation of monoculture on cultivated lands, soil fertility gradually decreases. This situation in ecology is called law of diminishing returns .

Thus, for prudent and rational farming it is necessary to take into account the depletion of soil resources and maintain soil fertility with the help of improved agricultural technology, rational crop rotation and other techniques.

The change of vegetation cover in agroecosystems does not occur naturally, but by the will of man, which does not always have a good effect on the quality of the abiotic factors included in it. This is especially true for soil fertility.

Main difference agroecosystems from natural ecosystems - getting extra energy for normal functioning.

Additional energy refers to any type of energy introduced into agroecosystems. This could be the muscular strength of humans or animals, various types of fuel for operating agricultural machines, fertilizers, pesticides, pesticides, additional lighting, etc. The concept of “additional energy” also includes new breeds of domestic animals and varieties of cultivated plants introduced into the structure of agroecosystems.

It should be noted that agroecosystems are highly fragile communities. They are not capable of self-healing and self-regulation, and are subject to the threat of death from mass reproduction of pests or diseases.

The reason for the instability is that agrocenoses are composed of one (monoculture) or, less often, a maximum of 2–3 species. That is why any disease, any pest can destroy an agrocenosis. However, people deliberately simplify the structure of the agrocenosis in order to obtain maximum production yield. Agrocenoses, to a much greater extent than natural cenoses (forest, meadow, pastures), are susceptible to erosion, leaching, salinization and pest invasion. Without human participation, agrocenoses of grain and vegetable crops exist for no more than a year, berry plants - 3-4, fruit crops - 20-30 years. They then disintegrate or die.

The advantage of agrocenoses Natural ecosystems are faced with the production of food necessary for humans and great opportunities for increasing productivity. However, they are implemented only with constant care for the fertility of the land, providing plants with moisture, protecting cultivated populations, varieties and breeds of plants and animals from the adverse effects of natural flora and fauna.

All agroecosystems of fields, gardens, pasture meadows, vegetable gardens, and greenhouses artificially created in agricultural practice are systems specifically supported by humans.

In relation to the communities that develop in agroecosystems, the emphasis is gradually changing in connection with the general development of environmental knowledge. In place of ideas about the fragmentary nature of coenotic connections and the extreme simplification of agrocenoses, there emerges an understanding of their complex systemic organization, where humans significantly influence only individual links, and the entire system continues to develop according to natural laws.

From an ecological point of view, it is extremely dangerous to simplify the natural environment of humans, turning the entire landscape into an agricultural one. The main strategy for creating a highly productive and sustainable landscape should be to preserve and enhance its diversity.

Along with maintaining highly productive fields, special care should be taken to preserve protected areas that are not subject to anthropogenic impact. Reserves with rich species diversity are a source of species for communities recovering in succession.

Comparative characteristics of natural ecosystems and agroecosystems

5.2.2.Industrial-urban ecosystems

The situation is completely different in ecosystems that include industrial-urban systems - here fuel energy completely replaces solar energy. Compared to the flow of energy in natural ecosystems, its consumption here is two to three orders of magnitude higher.

In connection with the above, it should be noted that artificial ecosystems cannot exist without natural systems, while natural ecosystems can exist without anthropogenic ones.

Urban systems

Urban system (urbosystem)- “an unstable natural-anthropogenic system consisting of architectural and construction objects and sharply disturbed natural ecosystems” (Reimers, 1990).

As the city develops, its functional zones become more and more differentiated - these are industrial, residential, forest park.

Industrial zones- these are areas where industrial facilities of various industries are concentrated (metallurgical, chemical, mechanical engineering, electronics, etc.). They are the main sources of environmental pollution.

Residential zones- these are areas where residential buildings, administrative buildings, cultural and educational facilities, etc. are concentrated.

Forest Park - This is a green area around the city, cultivated by man, that is, adapted for mass recreation, sports, and entertainment. Its sections are also possible inside cities, but usually here city ​​parks- tree plantations in the city, occupying quite large areas and also serving citizens for recreation. Unlike natural forests and even forest parks, city parks and similar smaller plantings in the city (squares, boulevards) are not self-sustaining and self-regulating systems.

Forest park zones, city parks and other areas of territory allocated and specially adapted for people’s recreation are called recreational zones (territories, sections, etc.).

The deepening of urbanization processes leads to the complication of the city's infrastructure. Beginning to occupy a significant place transport And transport facilities(roads, gas stations, garages, service stations, railways with their complex infrastructure, including underground ones - metro; airfields with a service complex, etc.). Transport systems cross all functional zones of the city and influence the entire urban environment (urban environment).

Environment surrounding a person under these conditions, it is a set of abiotic and social environments that jointly and directly influence people and their economy. At the same time, according to N.F. Reimers (1990), it can be divided into natural environment And natural environment transformed by man(anthropogenic landscapes up to the artificial environment of people - buildings, asphalt roads, artificial lighting, etc., i.e. artificial environment).

In general, the urban environment and urban-type settlements is part technosphere, that is, the biosphere, radically transformed by man into technical and man-made objects.

In addition to the terrestrial part of the landscape, its lithogenic basis, i.e., the surface part of the lithosphere, which is usually called the geological environment, also falls into the orbit of human economic activity (E.M. Sergeev, 1979).

Geological environment- these are rocks, groundwater, which are affected by human economic activity (Fig. 10.2).

In urban areas, in urban ecosystems, one can distinguish a group of systems that reflect the complexity of the interaction of buildings and structures with the environment, which are called natural-technical systems(Trofimov, Epishin, 1985) (Fig. 10.2). They are closely connected with anthropogenic landscapes, with their geological structure and relief.

Thus, urban systems are the concentration of population, residential and industrial buildings and structures. The existence of urban systems depends on the energy of fossil fuels and nuclear energy raw materials, and is artificially regulated and maintained by humans.

The environment of urban systems, both its geographical and geological parts, has been most strongly changed and, in fact, has become artificial, here problems of utilization and reutilization of natural resources involved in circulation, pollution and cleaning of the environment arise, here there is an increasing isolation of economic and production cycles from natural metabolism (biogeochemical turnover) and energy flow in natural ecosystems. And finally, it is here that the population density and the built environment are highest, which threaten not only human health, but also for the survival of all humanity. Human health is an indicator of the quality of this environment.

Natural ecosystems were formed as a result of the forces of nature. They are characterized by:

• Close relationship between organic and inorganic substances
• A complete, closed circle of the cycle of substances: starting from the appearance of organic matter and ending with its decay and decomposition into inorganic components.
• Resilience and self-healing ability.

All natural ecosystems are defined by the following characteristics:

• 1. Species structure: the number of each species of animal or plant is regulated by natural conditions.
  2. Spatial structure: all organisms are arranged in a strict horizontal or vertical hierarchy. For example, in a forest ecosystem, tiers are clearly distinguished; in an aquatic ecosystem, the distribution of organisms depends on the depth of the water.
  3. Biotic and abiotic substances. The organisms that make up the ecosystem are divided into inorganic (abiotic: light, air, soil, wind, humidity, pressure) and organic (biotic - animals, plants).
  4. In turn, the biotic component is divided into producers, consumers and destroyers. Producers include plants and bacteria, which use sunlight and energy to create organic matter from inorganic substances. Consumers are animals and carnivorous plants that feed on this organic matter. Destroyers (fungi, bacteria, some microorganisms) are the crown of the food chain, as they carry out the reverse process: organic matter is converted into inorganic substances.

Artificial ecosystems

Artificial ecosystems are communities of animals and plants living in conditions created for them by humans. They are also called noobiogeocenoses or socioecosystems. Examples: field, pasture, city, society, spaceship, zoo, garden, artificial pond, reservoir.

The simplest example of an artificial ecosystem is an aquarium. Here the habitat is limited by the walls of the aquarium, the flow of energy, light and nutrients is carried out by man, who also regulates the temperature and composition of the water. The number of inhabitants is also initially determined.

First feature: all artificial ecosystems are heterotrophic, i.e. consuming ready-made food. Let's take a city as an example - one of the largest artificial ecosystems. The influx of artificially created energy (gas pipeline, electricity, food) plays a huge role here. At the same time, such ecosystems are characterized by a large release of toxic substances. That is, those substances that later serve for the production of organic matter in a natural ecosystem often become unsuitable in artificial ones.

Another distinctive feature of artificial ecosystems is an open metabolic cycle. Let's take as an example agroecosystems - the most important for humans. These include fields, gardens, vegetable gardens, pastures, farms and other agricultural lands on which people create conditions for the production of consumer products. Part of the food chain in such ecosystems is removed by humans (in the form of crops), and therefore the food chain becomes destroyed.

The third difference between artificial ecosystems and natural ones is their small number of species. Indeed, a person creates an ecosystem for the sake of breeding one (less often several) species of plants or animals. For example, in a wheat field, all pests and weeds are destroyed, and only wheat is cultivated. This makes it possible to get a better harvest. But at the same time, the destruction of organisms that are “unprofitable” for humans makes the ecosystem unstable.

Comparative characteristics of natural and artificial ecosystems

It is more convenient to present a comparison of natural ecosystems and socioecosystems in the form of a table:

Artificial ecosystem - it is an anthropogenic, man-made ecosystem. All the basic laws of nature are valid for it, but unlike natural ecosystems, it cannot be considered open. The creation and observation of small artificial ecosystems allows us to obtain extensive information about the possible state of the environment due to large-scale human impacts on it. In order to produce agricultural products, humans create an unstable, artificially created and regularly maintained agroecosystem (agrobiocenosis ) - fields, pastures, vegetable gardens, orchards, vineyards, etc.

Differences between agrocenoses and natural biocenoses: insignificant species diversity (the agrocenosis consists of a small number of species with a high abundance); short power circuits; incomplete cycle of substances (some of the nutrients are carried out with the harvest); the source of energy is not only the Sun, but also human activity (land reclamation, irrigation, use of fertilizers); artificial selection (the effect of natural selection is weakened, selection is carried out by humans); lack of self-regulation (regulation is carried out by humans), etc. Thus, agrocenoses are unstable systems and can only exist with human support. As a rule, agroecosystems are characterized by high productivity compared to natural ecosystems.

Urban systems (urban systems) -- artificial systems (ecosystems) that arise as a result of urban development and represent a concentration of population, residential buildings, industrial, household, cultural objects, etc.

They include the following territories: industrial zones , where industrial facilities of various sectors of the economy are concentrated and are the main sources of environmental pollution; residential areas (residential or sleeping areas) with residential buildings, administrative buildings, everyday objects, cultural facilities, etc.); recreational areas , intended for people's recreation (forest parks, recreation centers, etc.); transport systems and structures , permeating the entire urban system (roads and railways, subways, gas stations, garages, airfields, etc.). The existence of urban ecosystems is supported by agroecosystems and the energy of fossil fuels and the nuclear industry.

An ecosystem is a collection of living organisms that continuously exchange matter, information and energy with each other and the environment. Energy is defined as the ability to produce work. Its properties are described by the laws of thermodynamics. The first law of thermodynamics, or the law of conservation of energy, states that energy can change from one form to another, but it is not destroyed or created anew.

The second law of thermodynamics states: during any transformation of energy, part of it is lost in the form of heat, i.e. becomes unavailable for further use. The measure of the amount of energy unavailable for use, or otherwise the measure of the change in order that occurs during the degradation of energy, is entropy. The higher the order of the system, the lower its entropy.

Spontaneous processes lead the system to a state of equilibrium with the environment, to an increase in entropy, and the production of positive energy. If an inanimate system, unbalanced with the environment, is isolated, then all movement in it will soon cease, the system as a whole will fade away and turn into an inert group of matter that is in thermodynamic equilibrium with the environment, that is, in a state with maximum entropy.

This is the most probable state for the system and it will not be able to get out of it spontaneously without external influences. So, for example, a hot frying pan, having cooled down, having dissipated the heat, will not heat up itself; the energy was not lost, it heated the air, but the quality of the energy changed, it can no longer do work. Thus, in nonliving systems their equilibrium state is stable.

Living systems have one fundamental difference from non-living systems - they perform constant work against equilibrium with the environment. In living systems, a non-equilibrium state is stable. Life is the only natural spontaneous process on Earth in which entropy decreases. This is possible because all living systems are open to the exchange of energy.

There is a huge amount of free energy from the Sun in the environment, and within the living system itself there are components that have mechanisms for capturing, concentrating and subsequently dissipating this energy in the environment. Energy dissipation, that is, an increase in entropy, is a process characteristic of any system, both inanimate and living, and independent capture and concentration of energy is the ability of only a living system. In this case, order and organization are extracted from the environment, that is, negative energy is generated - neentropy. This process of formation of order in a system from the chaos of the environment is called self-organization. It leads to a decrease in the entropy of a living system and counteracts its equilibrium with the environment.

Thus, any living system, including an ecosystem, maintains its vital activity due, firstly, to the presence of excess free energy in the environment; secondly, the ability to capture and concentrate this energy, and when used, dissipate states with low entropy into the environment.

Plants - producers - capture the energy of the Sun and convert it into potential energy of organic matter. The energy received in the form of solar radiation is converted into the energy of chemical bonds during the process of photosynthesis.

The energy of the Sun reaching the Earth is distributed as follows: 33% of it is reflected by clouds and dust of the atmosphere (this is the so-called albedo or reflectivity of the Earth), 67% is absorbed by the atmosphere, the surface of the Earth and the ocean. Of this amount of absorbed energy, only about 1% is spent on photosynthesis, and all the remaining energy, heating the atmosphere, land and ocean, is re-radiated into outer space in the form of thermal (infrared) radiation. This 1% of energy is enough to provide all the living matter on the planet.

The process of energy accumulation in the body of photosynthetics is associated with an increase in body weight. Ecosystem productivity is the rate at which producers absorb radiant energy through the process of photosynthesis, producing organic matter that can be used as food. The mass of substances created by the photosynthetic producer is designated as primary production; this is the biomass of plant tissues. Primary production is divided into two levels - gross and net production. Gross primary production is the total mass of gross organic matter created by a plant per unit time at a given rate of photosynthesis, including expenditure on respiration (part of the energy that is spent on vital processes; this leads to a decrease in biomass).

That part of the gross output that is not spent on breathing is called net primary production. Net primary production is a reserve, part of which is used as food by organisms - heterotrophs (consumers of the first order). The energy received by heterotrophs with food (the so-called high energy) corresponds to the energy cost of the total amount of food eaten. However, the efficiency of food absorption never reaches 100% and depends on the composition of the feed, temperature, season and other factors.

Functional connections in the ecosystem, i.e. its trophic structure can be depicted graphically in the form of ecological pyramids. The base of the pyramid is the producer level, and subsequent levels form the floors and the top of the pyramid. There are three main types of ecological pyramids.

The pyramid of numbers (Elton's pyramid) reflects the number of organisms at each level. This pyramid reflects a pattern - the number of individuals making up a sequential series of links from producers to consumers is steadily decreasing.

The biomass pyramid clearly indicates the amount of all living matter at a given trophic level. In terrestrial ecosystems, the rule of the biomass pyramid applies: the total mass of plants exceeds the mass of all herbivores, and their mass exceeds the entire biomass of predators. For the ocean, the rule of the biomass pyramid is invalid - the pyramid looks upside down. The ocean ecosystem is characterized by the accumulation of biomass at high levels, among predators.

The pyramid of energy (products) reflects the expenditure of energy in trophic chains. Energy pyramid rule: at each previous trophic level, the amount of biomass created per unit of time (or energy) is greater than at the next one.