A comparative description of one natural ecosystem and an agroecosystem. How agroecosystems differ from natural ecosystems: concepts and comparative characteristics

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)

Natural ecosystem (swamp, meadow, forest)	Anthropogenic ecosystem (field, factory, house)
Receives, converts, accumulates solar energy	Consumes energy from fossil and nuclear fuels
Produces oxygen and consumes carbon dioxide	Consumes oxygen and produces carbon dioxide when fossils are burned
Forms fertile soil	Depletes or poses a threat to fertile soils
Accumulates, purifies and gradually consumes water	Consumes a lot of water and pollutes it
Creates habitats for a variety of wildlife species	Destroys the habitats of many species of wildlife
Free filters and disinfects pollutants and waste	Produces pollutants and waste that must be decontaminated at the expense of the public
Has the ability self-preservation and self-healing	Requires high costs for constant maintenance and restoration

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 pest control - mostly necessary condition 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, a gradual decrease in soil fertility occurs. 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.

Changes in vegetation cover in agroecosystems do 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 may be the muscular strength of humans or animals, various types fuel for operating agricultural machinery, 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 intervention, 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, and 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 ecological 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

Natural ecosystems	Agroecosystems
Primary natural elementary units of the biosphere, formed during evolution	Secondary artificial elementary units of the biosphere transformed by humans
Complex systems with a significant number of animal and plant species in which populations of several species dominate. They are characterized by a stable dynamic balance achieved by self-regulation	Simplified systems with dominant populations of one plant or animal species. They are stable and characterized by the variability of the structure of their biomass
Productivity is determined by the adaptive characteristics of organisms participating in the cycle of substances	Productivity is determined by the level of economic activity and depends on economic and technical capabilities
Primary products are used by animals and participate in the cycle of substances. “Consumption” occurs almost simultaneously with “production”	The crop is harvested to satisfy human needs and feed livestock. Living matter accumulates for some time without being consumed. The highest productivity develops only for a short time

5.2.2.Industrial-urban ecosystems

The situation is completely different in ecosystems, which 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 pollution environment.

Residential zones- these are areas where residential buildings are concentrated, administrative buildings, objects of culture, education, etc.

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).

The 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 influenced 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 environmental cleanup 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.

Objective of the lesson:

To form in students a system of knowledge about the structure and functioning of biocenoses created by man, about the main features characterizing an agrocenosis.
Teach schoolchildren to compare natural biogeocenosis and agrocenosis; explain the reasons for the identified similarities and differences and be able to predict changes in them.
Convince high school students that between agrocenosis and natural biogeocenosis can be achieved harmonious combination that natural communities should not be completely replaced by agricultural land.
Learn to apply the acquired knowledge in life.
Ensure the assimilation of the material using educational resources "Electronic means of educational publication "Ecology" LLC "Drofa" CJSC "1C".

1. Organizational moment

Music is turned on with recordings of forest noise and birdsong.

Address to schoolchildren: “We have guests in our lesson today, look at them and smile, because you are glad to see them here today.”

2. Test of knowledge.

(The guys complete the task given on the sheets to the music)

1. In the list given, find and underline the names of producers, consumers and decomposers in different colors.

Fern, ant, porcini mushroom, chemosynthesizing bacterium, dragonfly, earthworm, putrefactive bacterium, cyanobacterium, lion, fly agaric, cactus, human.

2. Indicate (indicate by numbers) in what order the following organisms can enter the food chain: humans, unicellular algae, daphnia, pike perch, gudgeon.

3. Among the given statements, highlight the correct ones:

A. The source of energy for decomposers is the oxidation of inorganic substances.

B. The number of consumers is usually less than the number of producers.

B. The most highly productive ecosystem is the World Ocean.

D. The most unproductive ecosystems are deserts.

D. Highly productive ecosystems are self-reproducing, while low-productive ecosystems are not.

E. Ecosystems with low species diversity are unstable.

G. The existence of food webs is a condition for the sustainability of the ecosystem.

H. The mechanism of self-regulation of ecosystems is genetic drift.

I. Agrocenosis is one of the most stable ecosystems, because the effect of natural selection is reduced in it.

4. Complete the table using the list below

Artificial ecosystems	Natural ecosystems

Taiga, pond, lake, alpine meadow, wheat field, park, coral island.

What is the name of the natural biocenosis? (biogeocenosis).

What is the artificial biocenosis called? (agrocenosis).

Together with the students we check task 4.

The following diagram is written on the board:

Working with the definition of "agrocenosis"

From the Greek "agros" - field, "bios" - life, "cenosis" - general.

Definition: agrocenosis is a human-created biocenosis.

Using the electronic means of the educational publication "Ecology" LLC

"Bustard" JSC "1C" - video fragment "Agrocenosis and agroecosystem"

Let's turn to the table and compare biogeocenosis with agrocenosis. The material is printed on a separate sheet.

Look at the table and compare what is the peculiarity of artificial biogeocenosis?

Comparative characteristics of biogeocenoses and agrocenoses.

Comparison category	biogeocenosis	agrocenosis
Direction of selection action	Natural selection operates, culling non-viable individuals and preserving adaptations to environmental conditions, i.e. selection forms a stable ecosystem	The action of natural selection is weakened by man; predominantly artificial selection is carried out in the direction of preserving organisms with maximum productivity
Cycling of essential nutrients	All elements consumed by plants, animals and other organisms are returned to the soil, i.e. the cycle is completed completely.	Some of the nutrients are removed from the cycle with the mass of organisms grown and harvested, i.e. the cycle does not occur
Species diversity and sustainability	As a rule, they are distinguished by a large species diversity of organisms that are in complex relationships with each other, ensuring stability	The number of species is often limited to one or two; the interconnections of organisms cannot ensure stability.
Ability for self-regulation, self-maintenance and turnover	Self-regulating, constantly renewing, capable of directed replacement of one community by another (succession).	Regulated and controlled by man through change natural factors(irrigation), weed and pest control, changing varieties, increasing productivity.
Productivity (amount of biomass created per unit area)	Biomass of terrestrial ecosystems exceeds the productivity of the World Ocean ecosystems by 3 times; The main biomass production is consumed by consumers.	Occupying 10% of the land area, they produce 2.5 billion tons of agricultural products annually; are significantly more productive than biogeocenoses

Compare the ecosystem of a meadow and a field. Fill out the table:

Similarities between agrocenosis and natural biogeocenosis.

Are open systems(for example, they absorb solar energy from the outside).
Within each of them there are factors of evolution (artificial or natural selection, struggle for existence, hereditary variability)
They have a similar structure (consist of producers, consumers, decomposers).
In both biogeocenoses the rule of the ecological pyramid applies.
The community is based on producers (autotrophic organisms) that directly use the energy of the Sun for the synthesis of organic substances.
In biogeocenoses of any type, there are food chains.

This is interesting:

At the first stages of the development of agriculture agrocenoses were more stable than modern ones. Arable lands occupied relatively small areas surrounded by natural vegetation. The world of animals - regulators and pollinators - was rich. Cultivated plants were not pure varieties and represented a mixture of forms with different hereditary qualities. In dry years, some forms survived, in wet years, others. Weeds in the fields attracted a variety of insects. There was a system of connections close to natural. Such agrocenoses produced relatively low but reliable yields, and outbreaks of pests in them were rare.

With the development of intensive commercial farming, field productivity increased, but the stability and safety margins of ecosystems sharply decreased. More than 100 years ago, the law of diminishing returns was formulated, according to which agricultural production inevitably leads to soil depletion and degradation.

With development ecology It became clear that only planning of agricultural production based on ecosystem principles could suspend the operation of this law.

The advantage of biological methods of pest control is their selective action only on certain, undesirable ones in the agrocenosis. species.

Rice. 1.
Equestrians and egg eaters are human assistants in the fight against agricultural pests:
at the top and bottom left - female egg eaters on the eggs of the host insect
top right - aphid rider
bottom right - dead aphids after the development of parasites in them

Leaf-eating insects in small quantities they are useful for cultivated plants. Their activity brightens the leaf canopy and improves the light regime for photosynthesis. With a low proportion of damage, plants quickly regrow eaten foliage without loss of overall yield. Insect species that consume crop plants are considered pests when they exceed a certain level of abundance and their activity begins to reduce the yield. This level is called " threshold of harmfulness "If a species does not reach the threshold of harmfulness, it is not considered a pest and is not combated.

Cultivated plants vary greatly in their resistance to weeds. The amount of weeds that is detrimental to one species is almost not harmful to another. If we take the yield in pure sowing as one, then in heavily weeded areas it will leave 0.75 for wheat, 0.65 for potatoes, 0.56 for corn, 0.42 for flax, 0.23 for sugar beets, and 0.23 for cotton. 0.12. Thus, wheat is the most resistant crop to clogging. When 10-15% of the soil is covered with weeds, the costs of chemical weeding in wheat fields are usually not recouped by the increase in yield and the use of pesticides can be avoided.

Solve the problem.

Researchers have found that on every square meter In small cabbage fields there are on average up to 69 cabbage white caterpillars, and no more than one caterpillar was found in one square meter of large fields. At the same time, pests in both large fields and small fields are more concentrated in the marginal strip of agrocenoses 30-40 meters wide. Similar results were obtained when taking into account the population density of other crop pests: the cruciferous flea beetle complex, flax flea beetle, clover seed-eater and other phytophagous insects. Why is the number of insect pests of agricultural crops significantly higher at the edges of agrocenoses and small fields? What measures can be recommended to reduce the degree of damage to crops by phytophagous insects, taking into account the characteristics of their distribution.

Fixing the material:

1. Write down the food chains in agrocenoses. Why are food chains in agrocenosis small? What conditions should be observed when creating agrocenoses?

Why can’t agrocenoses prevail on the planet? What could this lead to?

Select from the following provisions what applies to agrocenosis and what to biogeocenosis:

consist of a large number of species;
capable of self-regulation;
incapable of self-regulation;
consist of a small number of species;
all nutrients absorbed by plants are returned to the soil over time;
a significant part of the nutrients is removed from the soil; to compensate for losses, it is necessary to constantly apply fertilizers;
the only source of energy is sunlight;
basic driving force evolution is artificial selection;
the main driving force of evolution is natural selection;
prosperity, conservation and high productivity are linked to human activity.

2. Think about why crop rotation is used in agrocenosis?

Homework:

General biology textbook for grades 10-11, edited by D.K. Belyaeva p.261-262.

1. Build a model of an artificial aquarium ecosystem, taking into account all the necessary conditions.

2. Draw up your own 5-field crop rotation scheme, taking into account the necessary requirements.

Having worked through these topics, you should be able to:

Give definitions: “ecology”, “ecological factor”, “photoperiodism”, “ecological niche”, “habitat”, “population”, “biocenosis”, “ecosystem”, “producer”, “consumer”, “decomposer”, "succession", "agrocenosis".
Give examples of photoperiodic reactions of plants and, if possible, animals.
Explain the difference between a population's habitat and its niche. Give examples for each of these concepts.
Comment on Shelford's law and be able to construct a graph of the dependence of organisms on abiotic environmental factors.
Describe an example of a successful biological pest control method.
Explain the causes of the population explosion and possible consequences, as well as the significance of the decline in fertility, which usually follows a decline in mortality.
Construct a food chain diagram; correctly indicate the traffic level of each component of a given ecosystem.
Construct a diagram of the simple cycle of the following elements: oxygen, nitrogen, carbon.
Describe the events that occur when the lake becomes overgrown; after deforestation.
Indicate the differences between agrocenosis and biocenosis.
Talk about the meaning and structure of the biosphere.
Explain how agriculture, the use of fossil fuels and the production of plastics contribute to environmental pollution and suggest measures to prevent this.

Ivanova T.V., Kalinova G.S., Myagkova A.N. "General Biology". Moscow, "Enlightenment", 2000

Topic 18. "Habitat. Environmental factors." chapter 1; pp. 10-58
Topic 19. "Populations. Types of relationships between organisms." chapter 2 §8-14; pp. 60-99; Chapter 5 § 30-33
Topic 20. "Ecosystems." chapter 2 §15-22; pp. 106-137
Topic 21. "Biosphere. Cycles of matter." Chapter 6 §34-42; pp. 217-290

- this is the interaction of living and inanimate nature, which consists of living organisms and their habitat. An ecological system is a large-scale balance and connection that allows the maintenance of a population of species of living things. Nowadays, there are natural and anthropogenic ecosystems. The differences between them are that the first is created by the forces of nature, and the second with the help of humans.

The meaning of agrocenosis

Agrocenosis is an ecosystem created by human hands for the purpose of producing crops, animals and mushrooms. An agrocenosis is also called an agroecosystem. Examples of agrocenosis are:

apple and other orchards;
corn and sunflower fields;
cow and sheep pastures;
vineyards;
vegetable gardens

Man, due to satisfying his needs and increasing population, has recently been forced to change and destroy natural ecosystems. In order to rationalize and increase the volume of agricultural crops, people create agroecosystems. Nowadays, 10% of all available land is occupied by land for growing crops, and 20% is pasture.

The difference between natural ecosystems and agrocenosis

The main differences between agrocenosis and natural ecosystems are:

artificially created crops cannot compete in the fight against wild species and;
agroecosystems are not adapted to self-healing, and are completely dependent on humans and without him they quickly weaken and die;
a large number of one species in the agroecosystem contributes to the large-scale development of viruses, bacteria and harmful insects;
There is a much greater diversity of species in nature than in human-grown crops.

Artificially created agricultural plots must be under full human control. A disadvantage of agrocenosis is the frequent increase in populations of pests and fungi, which not only harm the crop, but can also worsen the condition of the environment. The population size of a crop in an agrocenosis increases only through the use of:

weed and pest control;
dryland irrigation;
drying waterlogged soil;
replacement of crop varieties;
fertilizers with organic and mineral substances.

In the process of creating an agroecosystem, man built a completely artificial stages development Soil reclamation is very popular - an extensive set of measures aimed at improving natural conditions in order to get the maximum high level harvest. Only the correct scientific approach, monitoring soil conditions, moisture levels and mineral fertilizers are able to increase the productivity of agrocenosis in comparison with the natural ecosystem.

Negative consequences of agrocenosis

It is important for humanity to maintain a balance of agro- and natural ecosystems. People create agroecosystems to increase food supply and use them for food processing. However, the creation of artificial agroecosystems requires additional territories, so people often plow the land and thereby destroy existing natural ecosystems. This upsets the balance of wild and cultivated species of animals and plants.

The second negative role is played by pesticides, which are often used to control pests in agroecosystems. These chemicals Through water, air and insect pests they enter natural ecosystems and pollute them. In addition, excessive use of fertilizers for agroecosystems also causes groundwater problems.

The components of biogeocenosis and agrocenosis are the same components of the environment. In both systems, living organisms are united by territorial and food connections. But in each case you can notice its own characteristics.

Definition

Biogeocenosis is a self-developed ecosystem in which representatives of the living world are closely related to the inorganic components that make up their habitat. Examples: coniferous forest, flower meadow.

Agrocenosis is a system that appears when humans intervene in the space of the natural environment. Like biogeocenosis, it includes organic and inorganic parts. Examples: personal plot, corn field.

Comparison

When comparing the systems under consideration, one should first of all pay attention to their species composition. Biogeocenosis in this regard is characterized by greater diversity. In an agrocenosis, one or several crops chosen by humans for cultivation predominate (for example, potatoes planted on a plot), and, accordingly, the number of species of animals and lower organisms (bacteria, fungi) is also limited.

In this regard, power circuits in artificially created systems are shorter and simpler. However, in an area where there are many plants of the same species, all conditions are created for the life of harmful organisms that can coexist with such crops. Without experiencing biological competition, they can multiply vigorously and destroy crops or cause diseases in plants. As a result, the entire system is often in danger of destruction. Biogeocenosis is much more stable in this regard.

The difference between biogeocenosis and agrocenosis also lies in how the circulation of substances occurs in each case. In a natural community it is closed. Everything produced by plants (as well as their remains) is consumed by representatives of numerous food chains and returns to the soil, enriching it. At the same time, the agrocenosis is created precisely for the purpose of obtaining a harvest. Accordingly, at the time of harvesting operations, accompanied by a significant removal of biomass, the circulation of substances in such a system is disrupted, therefore in this case it is called unclosed. To maintain balance, fertilizers are added to the soil.

It is also important that the structure of biogeocenosis is formed through natural selection, eliminating weak species of organisms. Agrocenosis involves crops carefully selected by humans, taking into account the degree of their productivity. In other words, in formations of this type, artificial selection operates to a greater extent. At the same time, a person not only determines what will grow on the land area, but also ensures that additional energy enters the agrocenosis. For example, greenhouses are heated and artificial lighting is created. Meanwhile, ecosystems that exist without human intervention receive energy mainly from the Sun.

What is the difference between biogeocenosis and agrocenosis? The fact is that the latter brings real benefits to a person, since it serves as a source of necessary products. Biogeocenosis, in turn, is not always useful from a practical point of view. However, it is a stable self-regulating formation. The agrocenosis exists safely more or less long term only subject to human control. To maintain such a system requires the use of various agrotechnical techniques.

Table

Biogeocenosis	Agrocenosis
Created by nature	Artificially organized system
It is characterized by stability and self-regulation	Unstable, human adjustable
Species diversity	Small number of crops
Branched power circuits	Food chains are shorter and simpler
Less susceptible to pests, therefore more viable	Pests feel more comfortable in it, which can shorten the life of such a system
The cycle of substances is closed	The cycle of substances is not closed
Formed by natural selection	Artificial selection is leading
Receiving light and heat from the Sun	Sometimes additional energy is used, the supply of which is provided by a person
Doesn't always bring practical benefit to a person	Source of required products