Environmental problems are currently among the most pressing and priority on the planet. Much attention is paid to how people use lake ecosystems and forests. Behind great science lie terms that today not only schoolchildren, but also every self-respecting adult should know. We often hear "ecosystem pollution", what does this mean? What parts does an ecosystem consist of? The basics of discipline are taught already in elementary school. As an example, we can highlight the topic “Forest Ecosystem” (grade 3).

Why did ecology emerge as a science?

This is a relatively young biological discipline that emerged as a result of the rapid development of humankind’s labor activity. Intensified use of natural resources has led to disharmony between people and the surrounding world. The term "ecology", proposed by E. Haeckel in 1866, is literally translated from Greek as "the science of home, habitat, shelter." In other words, this is the doctrine of the relationship between living organisms and their environment.

Ecology, like any other science, did not arise immediately. It took almost 70 years for the concept of “ecosystem” to emerge.

Stages of development of science and first terms

In the 19th century, scientists accumulated knowledge, were engaged in describing environmental processes, generalizing and systematizing existing materials. The first naki terms began to appear. For example, K. Mobius proposed the concept of “biocenosis”. It is understood as a collection of living organisms that exist in the same conditions.

At the next stage of development of science, the main measurement category is identified - the ecosystem (A. J. Tansley in 1935 and R. Linderman in 1942). Scientists have been studying energy and trophic (nutrient) metabolic processes at the level of living and non-living components of the ecosystem.

At the third stage, the interaction of various ecosystems was analyzed. Then they were all combined into such a concept as the biosphere.

In recent years, science has mainly focused on the interaction of humans with the environment, as well as the destructive influence of anthropogenic factors.

What is an ecosystem?

This is a complex of living beings with their habitat, which is functionally united into a single whole. There is necessarily interdependence between these environmental components. There is a connection between living organisms and their environment at the level of substances, energy and information.

The term was first proposed in 1935 by the British botanist A. Tansley. He also determined what parts the ecosystem consists of. Russian biologist V.N. Sukachev introduced the concept of “biogeocenosis” (1944), which is less voluminous in relation to the ecosystem. Variants of biogeocenoses can be a spruce forest or a swamp. - ocean, Volga river.

All living organisms can be influenced by biotic, abiotic and anthropogenic environmental factors. For example:

• a frog ate a mosquito (biotic factor);
• a person gets wet in the rain (abiotic factor);
• people cut down the forest (anthropogenic factor).

Components

What parts does an ecosystem consist of? There are two main components or parts of an ecosystem - biotope and biocenosis. A biotope is a place or territory in which a living community (biocenosis) lives.

The concept of biotope includes not only the habitat itself (for example, soil or water), but also abiotic (non-living) factors. These include climatic conditions, temperature, humidity, etc.

Structure

Each one has a specific structure. It is characterized by the presence of certain varieties of living organisms that can comfortably exist in this environment. For example, the stag beetle lives in mountainous areas.

All types of living organisms are distributed in an ecosystem in a structured way: horizontally or vertically. The vertical structure is represented by plant organisms, which, depending on the amount of solar energy they need, are built into tiers or floors.

Often, in tests, schoolchildren are given the task of distributing floors in a forest ecosystem (grade 3). The lower floor is the litter (basement), which is formed by fallen leaves, pine needles, dead organisms, etc. The next tier (ground) is occupied by mosses, lichens, and mushrooms. A little higher there is grass; by the way, in some forests this floor may not exist. Next comes a layer of bushes and young shoots of trees, followed by small trees, and the topmost floor is occupied by large, tall trees.

The horizontal structure represents a mosaic arrangement of different types of organisms or microgroups depending on their food chains.

Important Features

Living organisms inhabiting a certain one feed on each other in order to preserve their vital functions. This is how food or trophic chains of an ecosystem are formed, which consist of links.

The first link includes producers or organisms that produce (produce), synthesize organic substances from inorganic ones. For example, a plant consumes carbon dioxide and releases oxygen and glucose, an organic compound, during photosynthesis.

The intermediate link is decomposers (saprotrophs or decomposers). These include organisms that are capable of decomposing the remains of non-living plants or animals. As a result, the transformation of organic matter into inorganic occurs. Reducers are microscopic fungi and bacteria.

The third link is represented by the group of consumers (consumers or heterotrophs), which includes humans. These living beings cannot synthesize organic compounds from inorganic ones, so they receive them in finished form from the environment. These include herbivorous organisms (cow, hare, etc.), the subsequent orders include carnivorous predators (tiger, lynx, lion), omnivores (bear, human).

Types of ecosystems

Any ecological system is open. It can also exist in an isolated form, its boundaries are blurred. Depending on the size, very small or microecological systems (human oral cavity), medium or mesoecological systems (forest edge, bay) and macroecological systems (ocean, Africa) are distinguished.

Depending on the method of origin, ecosystems are classified as spontaneously created or natural and artificial or man-made. Examples of ecosystems of natural formation: sea, stream; artificial - pond.

Based on their location in space, they distinguish between aquatic (puddle, ocean) and terrestrial (tundra, taiga, forest-steppe) ecological systems. The former, in turn, are divided into marine and freshwater. Freshwater can be lotic (stream or river), lentic (reservoir, lake, pond) and wetland (swamp).

Examples of ecosystems and their use by humans

Humans can have an anthropogenic effect on the ecosystem. Any use of nature by humans has an impact on the ecological system at the regional, national or planetary level.

As a result of excessive grazing, irrational environmental management and deforestation, two meso-ecosystems (field, forest) are destroyed at once, and in their place an anthropogenic desert is formed. Unfortunately, there are many such examples of ecosystems that can be cited.

How people use lake ecosystems is important on a regional scale. For example, with thermal pollution as a result of the discharge of heated water into a lake, it becomes swamped. Living creatures (fish, frogs, etc.) die, blue-green algae actively reproduce. The world's main supply of fresh water is concentrated in lakes. Consequently, pollution of these water bodies leads to disruption not only regional, but also the global ecosystem of the world.

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

• Biocenosis - a community of living organisms
• Biotope is the habitat of these organisms
• Types of connections between organisms in a given habitat
• The metabolism that occurs between these organisms in a given biotope.

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

To classify ecosystems, scientists chose one characteristic - habitat. This makes it more convenient to distinguish individual ecosystems, since it is the area that determines the climatic, bioenergetic and biological characteristics. Let's consider the types of ecosystems.

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

Agroecosystems is one of the types of artificial ecosystems created by man. They are distinguished by weak connections between components, a smaller species composition of organisms, and artificial interchange, but at the same time, it is agroecosystems that are the most productive. People create them for the sake of obtaining agricultural products. Examples of agroecosystems: arable lands, pastures, gardens, vegetable gardens, fields, planted forests, artificial ponds...

Forest ecosystems are communities 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.

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

The main thing in a forest ecosystem is plants, and the main one is one (less often several) plant species. All other living organisms are either consumers or destroyers, one way or another influencing the metabolism and energy...

Plants and animals are only an integral part of any ecosystem. Thus, 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 is inferior to flora in terms of species diversity, it is animals that ensure the stability of the ecosystem, 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 a fundamental factor for the existence of any ecosystem. They 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 represents a microecosystem at one or another stage of existence. For example, the trunk of a tree as it develops is one integral ecosystem. The trunk of a fallen tree is a different ecosystem. It’s the same with animals: an embryo in the reproductive stage 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. The diversity of animal and plant species, the condition, and stability of the aquatic ecosystem depend on five factors:

• Water salinity
• 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 waters occupy more than 70% of the earth's surface. These are oceans, seas, salt lakes. There is less freshwater: most of the rivers, lakes, swamps, ponds and other smaller bodies of water...

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 ES sustainability:

• Resistant is a type of sustainability in which an ecosystem is able to maintain its structure and functionality unchanged, despite changes in external conditions.
• Elastic— this type of sustainability 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, they speak specifically about the elastic stability of the ecosystem.
  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 place of birth and residence (be it a noisy metropolis or a village, an island or a large land, etc.) is part of an ecosystem....

Currently, human influence on any ecosystem is felt everywhere. For their own purposes, people either destroy or improve the ecosystems of our planet.

Thus, wasteful treatment of land, deforestation, and drainage of swamps are considered to be the destructive effects of humans. Conversely, the creation of nature reserves and the restoration of animal populations contribute to the restoration of the Earth’s ecological balance and is a creative influence of humans on ecosystems...

The main difference between such ecosystems is the method of their formation.

Natural, or natural ecosystems are created with the participation of natural forces. A person either has no influence on them at all, or there is an influence, but it is 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 a spaceship can be considered an example of a man-made ecosystem.

The main differences between artificial ecosystems and natural ones.

Ecosystem and its properties

Introduction

Word "ecology" formed from two Greek words: “oicos”, which means house, dwelling, and “logos” - science and is literally translated as the science of home, habitat. This term was first used by the German zoologist Ernst Haeckel in 1886, defining ecology as a field of knowledge that studies the economics of nature - the study of the general relationships of animals with both living and inanimate nature, including all both friendly and unfriendly relationships with which animals and plants come into contact directly or indirectly. This understanding of ecology has become generally accepted and today classical ecology is the science of studying the relationships of living organisms with their environment. Living matter so diverse that it is studied at different levels of the organization and from different angles. The organism, population and ecosystem levels are the area of ​​interest of classical ecology. Depending on the object of study and the angle from which it is studied, independent scientific directions have formed in ecology. Based on the size of the objects of study, ecology is divided into autecology (an organism and its environment), population ecology (a population and its environment), synecology (communities and their environment), biogeocytology (the study of ecosystems) and global ecology (the study of the Earth's biosphere). Depending on the object of study, ecology is divided into the ecology of microorganisms, fungi, plants, animals, humans, agroecology, industrial (engineering), human ecology, etc. Based on environments and components, the ecology of land, fresh water bodies, seas, deserts, highlands and other environmental and geographical spaces is distinguished. Ecology often includes a large number of related branches of knowledge, mainly in the field of environmental protection. This work examines, first of all, the basics of general ecology, that is, the classical laws of interaction of living organisms with the environment.

Ecosystem - the basic concept of ecology

Ecology reviews interaction between living organisms and inanimate nature. This interaction, firstly, occurs within a certain system (ecological system, ecosystem) and, secondly, it is not chaotic, but organized in a certain way, subject to laws. An ecosystem is a collection of producers, consumers and detritivores that interact with each other and with their environment through the exchange of matter, energy and information in such a way that this single system remains stable over a long period of time. Thus, a natural ecosystem is characterized by three features:

1) an ecosystem is necessarily a collection of living and nonliving components
2) within the ecosystem, a full cycle is carried out, starting with the creation of organic matter and ending with its decomposition into inorganic components;
3) the ecosystem remains stable for some time, which is ensured by a certain structure of biotic and abiotic components.

Examples of natural ecosystems are lake, forest, desert, tundra, land, ocean, biosphere. As can be seen from the examples, simpler ecosystems are included in more complexly organized ones. At the same time, a hierarchy of organization of systems, in this case environmental, is realized. Thus, the structure of nature should be considered as a systemic whole, consisting of ecosystems nested within one another, the highest of which is a unique global ecosystem - the biosphere. Within its framework, energy and matter are exchanged between all living and nonliving components on a planetary scale. The catastrophe threatening all of humanity is that one of the characteristics that an ecosystem should have is violated: the biosphere as an ecosystem has been removed from a state of stability by human activity. Due to its scale and variety of interrelations, it should not die from this; it will move into a new stable state, at the same time changing its structure, first of all inanimate, and after it, inevitably, living. Man as a biological species has less chance than others to adapt to new, rapidly changing external conditions and is most likely to disappear first. An instructive and clear example of this is the history of Easter Island. On one of the Polynesian islands, called Easter Island, as a result of complex migration processes in the 7th century, a closed civilization, isolated from the whole world, arose. In a favorable subtropical climate, over hundreds of years of existence, it reached certain heights of development, creating a unique culture and writing that is indecipherable to this day. And in the 17th century it perished without a trace, first destroying the flora and fauna of the island, and then destroying itself in progressive savagery and cannibalism. The last islanders no longer had the will and material to build life-saving “Noah’s arks” - boats or rafts. In memory of itself, the disappeared community left a semi-desert island with giant stone figures - witnesses of its former power. So, the ecosystem is the most important structural unit of the structure of the surrounding world. As can be seen from Fig. 1 (see appendix), the basis of ecosystems is made up of living matter, characterized by a biotic structure, and a habitat determined by a combination of environmental factors. Let's look at them in more detail.

Biotic structure of ecosystems

An ecosystem is based on the unity of living and nonliving matter. The essence of this unity is manifested in the following. From elements of inanimate nature, mainly CO2 and H2O molecules, under the influence of solar energy, organic substances are synthesized, which make up all life on the planet. The process of creating organic matter in nature occurs simultaneously with the opposite process - the consumption and decomposition of this substance again into its original inorganic compounds. The combination of these processes occurs within ecosystems of various levels of hierarchy. In order for these processes to be balanced, nature has worked out a certain structure of the living matter of the system over billions of years. The driving force in any material system is energy. It comes into ecosystems mainly from the Sun.. Plants, due to the chlorophyll pigment they contain, capture the energy of solar radiation and use it to synthesize the basis of any organic substance - glucose C6H12O6.
The kinetic energy of solar radiation is thus converted into potential energy stored by glucose. From glucose, together with mineral nutrients obtained from the soil - biogens - all the tissues of the plant world are formed - proteins, carbohydrates, fats, lipids, DNA, RNA, that is, the organic matter of the planet.
In addition to plants, some bacteria can produce organic matter. They create their tissues by storing in them, like plants, potential energy from carbon dioxide without the participation of solar energy. Instead, they use energy that is generated by the oxidation of inorganic compounds, such as ammonia, iron and especially sulfur (in deep ocean basins, where sunlight does not penetrate, but where hydrogen sulfide accumulates in abundance, unique ecosystems have been discovered). This is the so-called energy of chemical synthesis, which is why organisms are called chemosynthetics. Thus, plants and chemosynthetics create organic matter from inorganic components using environmental energy. They are called producers or autotrophs. The release of potential energy stored by producers ensures the existence of all other species of life on the planet. Species that consume organic matter created by producers as a source of matter and energy for their life activity are called consumers or heterotrophs.- these are a wide variety of organisms (from microorganisms to blue whales): protozoa, insects, reptiles, fish, birds and, finally, mammals, including humans. Consumers, in turn, are divided into a number of subgroups according to differences in their food sources. Animals that feed directly on producers are called primary consumers or first-order consumers. They themselves are consumed by secondary consumers. For example, a rabbit eating carrots is a first-order consumer, and a fox hunting a rabbit is a second-order consumer. Some species of living organisms correspond to several such levels. For example, when a person eats vegetables, he is a consumer of the first order, beef is a consumer of the second order, and when he eats predatory fish, he acts as a consumer of the third order.

Primary consumers that feed only on plants are called herbivores or phytophages. Consumers second and higher orders- carnivores. Species that eat both plants and animals are classified as omnivores, such as humans. Dead plant and animal remains, such as fallen leaves, animal carcasses, products of excretory systems, are called detritus. It's organic! There are many organisms that specialize in feeding on detritus. They are called detritivores. Examples include vultures, jackals, worms, crayfish, termites, ants, etc. As in the case of ordinary consumers, there are primary detritivores, feeding directly on detritus, secondary, etc. Finally, a significant part of the detritus in the ecosystem, in particular fallen leaves, dead wood, in its original form is not eaten by animals, but rots and decomposes in the process of feeding fungi and bacteria. Since the role of fungi and bacteria is so specific, they are usually classified as a special group of detritivores and called decomposers. Decomposers serve as orderlies on Earth and close the biogeochemical cycle of substances, decomposing organic matter into its original inorganic components - carbon dioxide and water. Thus, despite the diversity of ecosystems, they all have structural similarities. In each of them it is possible to distinguish photosynthetic plants - producers, various levels of consumers, detritivores and decomposers. They constitute the biotic structure of ecosystems.

Environmental factors

The inanimate and living nature surrounding plants, animals and humans is called habitat. The many individual components of the environment that influence organisms are called environmental factors. According to the nature of origin, abiotic, biotic and anthropogenic factors are distinguished. Abiotic factors are properties of inanimate nature that directly or indirectly affect living organisms. Biotic factors are all forms of influence of living organisms on each other. Previously, human influence on living organisms was also classified as biotic factors, but now a special category of factors generated by humans is distinguished. Anthropogenic factors are all forms of activity of human society that lead to changes in nature as a habitat and other species and directly affect their lives. Thus, every living organism is influenced by inanimate nature, organisms of other species, including humans, and, in turn, affects each of these components.

Laws of the influence of environmental factors on living organisms

Despite the variety of environmental factors and the different nature of their origin, there are some general rules and patterns of their impact on living organisms. For organisms to live, a certain combination of conditions is necessary. If all environmental conditions are favorable, with the exception of one, then this condition becomes decisive for the life of the organism in question. It limits (limites) the development of the organism, therefore it is called a limiting factor. Initially, it was found that the development of living organisms is limited by the lack of any component, for example, mineral salts, moisture, light, etc. In the mid-19th century, the German organic chemist Eustace Liebig was the first to experimentally prove that plant growth depends on the nutrient element that is present in relatively minimal quantities. He called this phenomenon the law of the minimum; in honor of the author it is also called Liebig's law. In its modern formulation, the law of the minimum sounds like this: the endurance of an organism is determined by the weakest link in the chain of its environmental needs. However, as it turned out later, not only a deficiency, but also an excess of a factor can be limiting, for example, crop loss due to rain, oversaturation of the soil with fertilizers, etc. The concept that, along with a minimum, a maximum can also be a limiting factor was introduced 70 years after Liebig by the American zoologist W. Shelford, who formulated the law of tolerance. According to the law of tolerance, the limiting factor in the prosperity of a population (organism) can be either a minimum or maximum environmental impact, and the range between them determines the amount of endurance (tolerance limit) or the ecological valence of the organism to a given factor. The favorable range of action of an environmental factor is called the zone of optimum (normal life activity). The more significant the deviation of a factor’s action from the optimum, the more this factor inhibits the vital activity of the population. This range is called the inhibition zone. The maximum and minimum transferable values ​​of a factor are critical points beyond which the existence of an organism or population is no longer possible. In accordance with the law of tolerance, any excess of matter or energy turns out to be a source of environmental pollution. Thus, excess water even in arid areas is harmful and water can be considered as a common pollutant, although it is absolutely necessary in optimal quantities. In particular, excess water prevents normal soil formation in the chernozem zone. Species whose existence requires strictly defined environmental conditions are called stenobiotic, and species that adapt to an ecological situation with a wide range of changes in parameters are called eurybiotic. Among the laws that determine the interaction of an individual or individual with its environment, we highlight the rule of compliance of environmental conditions with the genetic predetermination of the organism. It states that a species of organisms can exist as long as the natural environment surrounding it corresponds to the genetic capabilities of adapting this species to its fluctuations and changes.

Abiotic environmental factors

Abiotic factors - these are the properties of inanimate nature, that directly or indirectly affect living organisms. In Fig. Table 5 (see appendix) shows the classification of abiotic factors. Let's start our consideration with climatic factors of the external environment. Temperature is the most important climatic factor. The intensity of metabolism of organisms and their geographical distribution depend on it. Any organism is capable of living within a certain temperature range. And although these intervals are different for different types of organisms (eurythermic and stenothermic), for most of them the zone of optimal temperatures, at which vital functions are carried out most actively and efficiently, is relatively small. The temperature range in which life can exist is approximately 300 C: from -200 to +100 BC. But most species and most activity are confined to an even narrower range of temperatures. Certain organisms, especially those in the dormant stage, can survive for at least some time at very low temperatures. Certain types of microorganisms, mainly bacteria and algae, are able to live and reproduce at temperatures close to the boiling point. The upper limit for hot spring bacteria is 88 C, for blue-green algae - 80 C, and for the most resistant fish and insects - about 50 C. As a rule, the upper limit values ​​of the factor are more critical than the lower ones, although many organisms near the upper limits of the tolerance range function more effectively. Aquatic animals tend to have a narrower range of temperature tolerance than terrestrial animals because the temperature range in water is smaller than on land. Thus, temperature is an important and very often limiting factor. Temperature rhythms largely control the seasonal and daily activity of plants and animals.

Rainfall and humidity- the main quantities measured when studying this factor. The amount of precipitation depends mainly on the paths and nature of large movements of air masses. For example, winds blowing from the ocean leave most of the moisture on the slopes facing the ocean, resulting in a “rain shadow” behind the mountains, which contributes to the formation of the desert. Moving inland, the air accumulates a certain amount of moisture, and the amount of precipitation increases again. Deserts tend to be located behind high mountain ranges or along coastlines where winds blow from vast inland dry areas rather than from the ocean, such as the Nami Desert in South West Africa. The distribution of precipitation over the seasons is an extremely important limiting factor for organisms. Humidity is a parameter characterizing the content of water vapor in the air. Absolute humidity is the amount of water vapor per unit volume of air. Due to the dependence of the amount of steam retained by air on temperature and pressure, the concept of relative humidity was introduced - this is the ratio of the steam contained in the air to the saturated steam at a given temperature and pressure. Since in nature there is a daily rhythm of humidity - an increase at night and a decrease during the day, and its fluctuation vertically and horizontally, this factor, along with light and temperature, plays an important role in regulating the activity of organisms. The supply of surface water available to living organisms depends on the amount of precipitation in a given area, but these values ​​do not always coincide. Thus, using underground sources, where water comes from other areas, animals and plants can receive more water than from receiving it with precipitation. Conversely, rainwater sometimes immediately becomes inaccessible to organisms. Radiation from the Sun consists of electromagnetic waves of various lengths. It is absolutely necessary for living nature, as it is the main external source of energy. It must be borne in mind that the spectrum of electromagnetic radiation from the Sun is very wide and its frequency ranges affect living matter in different ways.

For living matter, the qualitative characteristics of light are important - wavelength, intensity and duration of exposure. Ionizing radiation knocks electrons out of atoms and attaches them to other atoms to form pairs of positive and negative ions. Its source is radioactive substances contained in rocks, in addition, it comes from space. Different types of living organisms differ greatly in their ability to withstand large doses of radiation exposure. Most studies show that rapidly dividing cells are most sensitive to radiation. In higher plants, sensitivity to ionizing radiation is directly proportional to the size of the cell nucleus, or more precisely to the volume of chromosomes or DNA content. The gas composition of the atmosphere is also an important climatic factor. Approximately 3-3.5 billion years ago, the atmosphere contained nitrogen, ammonia, hydrogen, methane and water vapor, and there was no free oxygen in it. The composition of the atmosphere was largely determined by volcanic gases. Due to the lack of oxygen, there was no ozone screen to block ultraviolet radiation from the Sun. Over time, due to abiotic processes, oxygen began to accumulate in the planet’s atmosphere, and the formation of the ozone layer began. The wind can even change the appearance of plants, especially in those habitats, for example in alpine zones, where other factors have a limiting effect. It has been experimentally shown that in open mountain habitats the wind limits plant growth: when a wall was built to protect the plants from the wind, the height of the plants increased. Storms are of great importance, although their effect is purely local. Hurricanes and ordinary winds can transport animals and plants over long distances and thereby change the composition of communities. Atmospheric pressure does not appear to be a direct limiting factor, but it is directly related to weather and climate, which have a direct limiting effect.

Water conditions create a unique habitat for organisms, differing from ground water primarily in density and viscosity. The density of water is approximately 800 times, and the viscosity is approximately 55 times higher than that of air. Along with density and viscosity, the most important physical and chemical properties of the aquatic environment are: temperature stratification, that is, changes in temperature along the depth of a water body and periodic changes in temperature over time, as well as water transparency, which determines the light regime under its surface: photosynthesis of green and purple algae, phytoplankton, higher plants. As in the atmosphere, the gas composition of the aquatic environment plays an important role. In aquatic habitats, the amount of oxygen, carbon dioxide and other gases dissolved in water and therefore available to organisms varies greatly over time. In reservoirs with a high content of organic matter, oxygen is a limiting factor of paramount importance. Acidity - the concentration of hydrogen ions (pH) - is closely related to the carbonate system. The pH value varies in the range from 0 pH to 14: at pH = 7 the environment is neutral, at pH<7 - кислая, при рН>7 - alkaline. If acidity does not approach extreme values, then communities are able to compensate for changes in this factor - the community's tolerance to the pH range is very significant. Waters with low pH contain few nutrients, so productivity is extremely low. Salinity - content of carbonates, sulfates, chlorides, etc. - is another significant abiotic factor in water bodies. There are few salts in fresh waters, of which about 80% are carbonates. The content of minerals in the world's oceans averages 35 g/l. Open ocean organisms are generally stenohaline, whereas coastal brackish water organisms are generally euryhaline. The salt concentration in the body fluids and tissues of most marine organisms is isotonic with the salt concentration in seawater, so there are no problems with osmoregulation. The current not only greatly influences the concentration of gases and nutrients, but also directly acts as a limiting factor. Many river plants and animals are morphologically and physiologically specially adapted to maintaining their position in the flow: they have well-defined limits of tolerance to the flow factor. Hydrostatic pressure in the ocean is of great importance. With immersion in water of 10 m, the pressure increases by 1 atm (105 Pa). In the deepest part of the ocean the pressure reaches 1000 atm (108 Pa). Many animals are able to tolerate sudden fluctuations in pressure, especially if they do not have free air in their bodies. Otherwise, gas embolism may develop. High pressures, characteristic of great depths, as a rule, inhibit vital processes.

The soil

Soil is the layer of material lying on top of the rocks of the earth's crust.. Russian scientist - naturalist Vasily Vasilievich Dokuchaev in 1870, he was the first to consider soil as a dynamic rather than an inert medium. He proved that the soil is constantly changing and developing, and chemical, physical and biological processes take place in its active zone. Soil is formed through a complex interaction of climate, plants, animals and microorganisms. The composition of the soil includes four main structural components: mineral base (usually 50-60% of the total soil composition), organic matter (up to 10%), air (15-25%) and water (25-30%). The mineral skeleton of soil is the inorganic component that is formed from the parent rock as a result of its weathering. Soil organic matter is formed by the decomposition of dead organisms, their parts and excrement. Incompletely decomposed organic remains are called litter, and the final product of decomposition - an amorphous substance in which it is no longer possible to recognize the original material - is called humus. Thanks to its physical and chemical properties, humus improves soil structure and aeration, and increases the ability to retain water and nutrients. The soil is home to many species of plant and animal organisms that influence its physicochemical characteristics: bacteria, algae, fungi or protozoa, worms and arthropods. Their biomass in different soils is equal (kg/ha): bacteria 1000-7000, microscopic fungi - 100-1000, algae 100-300, arthropods - 1000, worms 350-1000. The main topographic factor is altitude above sea level. With altitude, average temperatures decrease, daily temperature differences increase, precipitation, wind speed and radiation intensity increase, atmospheric pressure and gas concentrations decrease. All these factors influence plants and animals, causing vertical zonation. Mountain ranges can act as climate barriers. Mountains also serve as barriers to the spread and migration of organisms and can play the role of a limiting factor in the processes of speciation.
Another topographic factor is slope exposure. In the northern hemisphere, south-facing slopes receive more sunlight, so the light intensity and temperature here are higher than on valley floors and northern-facing slopes. In the southern hemisphere the opposite situation occurs. An important relief factor is also the steepness of the slope. Steep slopes are characterized by rapid drainage and soil washing away, so the soils here are thin and drier. For abiotic conditions, all the considered laws of the influence of environmental factors on living organisms are valid. Knowledge of these laws allows us to answer the question: why did different ecosystems form in different regions of the planet? The main reason is the unique abiotic conditions of each region.

Biotic relationships and the role of species in the ecosystem

Distribution areas and numbers of organisms of each species are limited not only by the conditions of the external non-living environment, but also by their relationships with organisms of other species. The immediate living environment of an organism constitutes its biotic environment, and the factors of this environment are called biotic. Representatives of each species are able to exist in an environment where connections with other organisms provide them with normal living conditions. Let us consider the characteristic features of relationships of various types. Competition is the most comprehensive type of relationship in nature, in which two populations or two individuals, in the struggle for the conditions necessary for life, influence each other negatively. Competition can be intraspecific and interspecific. Intraspecific competition occurs between individuals of the same species, interspecific competition occurs between individuals of different species. Competitive interaction may concern living space, food or nutrients, light, shelter and many other vital factors. Interspecific competition, regardless of what underlies it, can lead either to the establishment of equilibrium between two species, or to the replacement of the population of one species by the population of another, or to the fact that one species will displace another to another place or force it to move to another place. use of other resources. It has been established that two species identical in ecological terms and needs cannot coexist in one place and sooner or later one competitor displaces the other. This is the so-called exclusion principle or Gause principle.

1) relationships between living organisms are one of the main regulators of the number and spatial distribution of organisms in nature;

2) negative interactions between organisms appear at the initial stages of community development or in disturbed natural conditions; in recently formed or new associations, the likelihood of strong negative interactions occurring is greater than in old associations;

3) in the process of evolution and development of ecosystems, a tendency is revealed to reduce the role of negative interactions at the expense of positive ones that increase the survival of interacting species.

A person must take into account all these circumstances when carrying out measures to manage ecological systems and individual populations in order to use them in his own interests, as well as anticipate the indirect consequences that may occur.

Ecosystem functioning

Energy in ecosystems.

Recall that an ecosystem is a collection of living organisms continuously exchanging energy, matter and information with each other and with the environment. Let us first consider the process of energy exchange. Energy is defined as the ability to produce work. The properties of energy are described by the laws of thermodynamics.
The first law (law) of thermodynamics or the law of conservation of energy states that energy can change from one form to another, but it does not disappear or be created anew. Second law (beginning) of thermodynamics or the law of entropy states that in a closed system entropy can only increase. In relation to energy in ecosystems, the following formulation is convenient: processes associated with energy transformations can occur spontaneously only under the condition that the energy passes from a concentrated form to a dispersed one, that is, it degrades. The measure of the amount of energy that becomes 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. Thus, any living system, including an ecosystem, maintains its vital activity thanks to, firstly, the presence in the environment of an excess of free energy (the energy of the Sun); secondly, the ability, due to the design of its components, to capture and concentrate this energy, and when used, to dissipate it into the environment. Thus, first capturing and then concentrating energy with the transition from one trophic level to another ensures an increase in the orderliness and organization of a living system, that is, a decrease in its entropy.

Ecosystem Energy and Productivity

So, life in an ecosystem is maintained due to the continuous passage of energy through living matter, transferred from one trophic level to another; At the same time, there is a constant transformation of energy from one form to another. In addition, during energy transformations, part of it is lost in the form of heat.
Then the question arises: in what quantitative relationships and proportions should members of the community of different trophic levels in the ecosystem be among themselves in order to meet their energy needs?

The entire energy reserve is concentrated in the mass of organic matter- biomass, therefore the intensity of the formation and destruction of organic matter at each level is determined by the passage of energy through the ecosystem (biomass can always be expressed in energy units). The rate of formation of organic matter is called productivity. There are primary and secondary productivity. In any ecosystem, biomass is formed and destroyed, and these processes are entirely determined by the life of the lower trophic level - the producers. All other organisms only consume the organic matter already created by plants and, therefore, the overall productivity of the ecosystem does not depend on them. High rates of biomass production are observed in natural and artificial ecosystems where abiotic factors are favorable, and especially when additional energy is supplied from outside, which reduces the system’s own costs of maintaining life. This additional energy can come in different forms: for example, in a cultivated field - in the form of fossil fuel energy and work done by humans or animals. Thus, to provide energy to all individuals of a community of living organisms in an ecosystem, a certain amount of energy is required. quantitative relationship between producers, consumers of different orders, detritivores and decomposers. However, for the life activity of any organisms, and therefore the system as a whole, energy alone is not enough; they must receive various mineral components, trace elements, and organic substances necessary for the construction of molecules of living matter.

Cycle of elements in an ecosystem

Where do the components necessary to build an organism initially come from in living matter? They are supplied to the food chain by the same producers. They extract inorganic minerals and water from the soil, CO2 from the air, and from glucose formed during photosynthesis, with the help of nutrients, they further build complex organic molecules - carbohydrates, proteins, lipids, nucleic acids, vitamins, etc. In order for the necessary elements to be available to living organisms, they must be available at all times. In this relationship, the law of conservation of matter is realized. It is convenient to formulate it as follows: atoms in chemical reactions never disappear, are not formed or transform into each other; they only rearrange to form various molecules and compounds (at the same time, energy is absorbed or released). Because of this, atoms can be used in a wide variety of compounds and their supply is never depleted. This is exactly what happens in natural ecosystems in the form of cycles of elements. In this case, two cycles are distinguished: large (geological) and small (biotic). The water cycle is one of the grandest processes on the surface of the globe. It plays a major role in linking geological and biotic cycles. In the biosphere, water, continuously moving from one state to another, makes small and large cycles. The evaporation of water from the surface of the ocean, the condensation of water vapor in the atmosphere and the precipitation on the surface of the ocean form a small cycle. If water vapor is carried by air currents to land, the cycle becomes much more complicated. In this case, part of the precipitation evaporates and goes back into the atmosphere, the other feeds rivers and reservoirs, but ultimately returns to the ocean again by river and underground runoff, thereby completing the large cycle. An important property of the water cycle is that, interacting with the lithosphere, atmosphere and living matter, it links together all parts of the hydrosphere: the ocean, rivers, soil moisture, groundwater and atmospheric moisture. Water is the most important component of all living things. Groundwater, penetrating through plant tissue during the process of transpiration, introduces mineral salts necessary for the life of the plants themselves. Summarizing the laws of ecosystem functioning, let us formulate once again their main provisions:

1) natural ecosystems exist due to non-polluting free solar energy, the amount of which is excessive and relatively constant;

2) the transfer of energy and matter through the community of living organisms in the ecosystem occurs along the food chain; all species of living things in an ecosystem are divided according to the functions they perform in this chain into producers, consumers, detritivores and decomposers - this is the biotic structure of the community; the quantitative ratio of the number of living organisms between trophic levels reflects the trophic structure of the community, which determines the rate of passage of energy and matter through the community, that is, the productivity of the ecosystem;

3) natural ecosystems, due to their biotic structure, maintain a stable state indefinitely, without suffering from resource depletion and pollution by their own waste; obtaining resources and getting rid of waste occur within the cycle of all elements.

Human impact on the ecosystem

The human impact on the natural environment can be considered in different aspects, depending on the purpose of studying this issue. From an environmental point of view, it is of interest consideration of human impact on ecological systems from the point of view of compliance or contradiction of human actions with the objective laws of the functioning of natural ecosystems. Based on the view of the biosphere as a global ecosystem, all the diversity of human activities in the biosphere leads to changes in: the composition of the biosphere, the cycles and balance of its constituent substances; energy balance of the biosphere; biota. The direction and extent of these changes are such that man himself gave them the name of an ecological crisis. The modern environmental crisis is characterized by the following manifestations:

Gradual change in the planet's climate due to changes in the balance of gases in the atmosphere;
- general and local (over the poles, individual land areas) destruction of the biosphere ozone screen;
- pollution of the World Ocean with heavy metals, complex organic compounds, petroleum products, radioactive substances, saturation of waters with carbon dioxide;
- disruption of natural ecological connections between the ocean and land waters as a result of the construction of dams on rivers, leading to changes in solid runoff, spawning routes, etc.;
- atmospheric pollution with the formation of acid precipitation, highly toxic substances as a result of chemical and photochemical reactions;
- pollution of land waters, including river waters, used for drinking water supply, with highly toxic substances, including dioxins, heavy metals, phenols;
- desertification of the planet;
- degradation of the soil layer, reduction in the area of ​​fertile land suitable for agriculture;
- radioactive contamination of certain territories due to the disposal of radioactive waste, man-made accidents, etc.;
- accumulation of household garbage and industrial waste on the land surface, especially practically non-degradable plastics;
- reduction in the areas of tropical and northern forests, leading to an imbalance of atmospheric gases, including a reduction in the concentration of oxygen in the planet’s atmosphere;
- pollution of underground space, including groundwater, which makes it unsuitable for water supply and threatens the still little studied life in the lithosphere;
- massive and rapid, avalanche-like disappearance of species of living matter;
- deterioration of the living environment in populated areas, especially urban areas;
- general depletion and lack of natural resources for human development;
- changes in the size, energetic and biogeochemical role of organisms, reformation of food chains, mass reproduction of certain types of organisms;
- violation of the hierarchy of ecosystems, increasing systemic uniformity on the planet.

Conclusion

When environmental problems became the center of attention of the world community in the mid-sixties of the twentieth century, the question arose: how much time does humanity have left? When will it begin to reap the benefits of neglecting its environment? Scientists have calculated: in 30-35 years. That time has come. We witnessed a global environmental crisis, caused by human activity. However, the last thirty years have not been in vain: a more solid scientific basis for understanding environmental problems has been created, regulatory bodies have been formed at all levels, numerous public environmental groups have been organized, useful laws and regulations have been adopted, and some international agreements have been reached. However, it is mainly the consequences, not the causes, of the current situation that are eliminated. For example, people use more and more pollution control products on cars and try to extract more and more oil instead of questioning the very need to satisfy excessive needs. Humanity hopelessly trying to save from extinction, several species, not paying attention to their own demographic explosion, wiping out natural ecosystems from the face of the earth. The main conclusion from the material discussed in the textbook is absolutely clear: systems that contradict natural principles and laws are unstable. Attempts to preserve them are becoming increasingly expensive and difficult and are in any case doomed to failure. To make long-term decisions, it is necessary to pay attention to the principles that define sustainable development, namely:

Population stabilization;
- transition to a more energy- and resource-saving lifestyle;
- development of environmentally friendly energy sources;
- creation of low-waste industrial technologies;
- waste recycling;
- creation of balanced agricultural production that does not deplete soil and water resources and does not pollute the land and food;
- preservation of biological diversity on the planet.

Bibliography

1. Nebel B. Environmental science: How the world works: In 2 volumes - M.: Mir, 1993.
2. Odum Yu. Ecology: In 2 vols. - M.: Mir, 1986.
3. Reimers N.F. Protection of nature and the human environment: Dictionary-reference book. - M.: Education, 1992. - 320 p.
4. Stadnitsky G.V., Rodionov A.I. Ecology.
5. M.: Higher. school, 1988. - 272 p.

01/15/2018 article

TEXT ECOCOSM

The term “ecosystem” is familiar to each of us from school and, if we look deeper into the recesses of memory, today we can say: an ecosystem is the functional unity of living organisms and their habitat (that is, the inanimate nature surrounding these organisms). And this is the answer to “excellent”... for a sixth grader.

In fact, the essence and role of ecological systems is much more complex than it might seem at first glance. Being the main functional units of ecology and structural components of the biosphere, ecosystems are amazing not only for their species diversity, but also for the wide range of functions that they perform.

The critical importance that ecological systems have for humanity is an opportunity to get to know them better and learn something new about them – something that might be a revelation for you.

How did the concept of an ecosystem emerge?

The existence of a close relationship between all living organisms in nature was no secret already in ancient times. People could not help but notice the patterns that unite various natural processes, but the term designating the totality of living organisms in a certain habitat did not exist at that time.

At the end of the 19th century, the German scientist K. Möbius took another step towards defining the concept of an ecosystem, giving the community of organisms in an oyster bank the name “biocenosis”. And in 1887, thanks to his American colleague S. Forbes, the term “microcosm” appears, which he uses to define the lake in conjunction with all the organisms living in it.

The emergence of the term “ecosystem”

Moscow Chistye Prudy received its current name only at the beginning of the 18th century after they were put in order through the efforts of Prince Menshikov, whose property they became at that time. Previously, the ponds were called Poganykh, acting as a giant sewer.

The term “ecological system” in the sense in which it is familiar to us today was introduced into use relatively recently. – in 1935 – English biologist Arthur Tansley.

A scientist defines an ecosystem as a set of objects of living and inanimate nature. Simply put – organisms and their habitats.

Along with this term, similar concepts appear in related sciences. For example, in geology the concept of “geosystem” is becoming widespread, and F. Clements introduced the term “Holocene” in 1930. IN AND. Vernadsky owns the name “bio-inert body”, which he introduced into use in 1944. Judging objectively, the concept of ecosystems is basic for all areas of environmental science.

Ecosystem in detail

The main features of any ecological system are its openness and ability for self-regulation, self-organization and self-development. Thus, not every biological system can be called an ecosystem, since not each of them has a certain self-sufficiency and cannot exist for a long time without external regulation. A striking example of a biosystem that is not an ecosystem is an aquarium or a pool with fish.

Such a community is just a part of a more complex system and is called a “microcosm” or “facies” (in geoecology).

Ecosystem and biogeocenosis

The whim of a member of the New York Biological Society, Evgeniy Sheffelin, ended in environmental disaster. For the past 100 years, the starlings he brought to New York's Central Park have been seriously disrupting the functioning of all ecosystems in the United States, with the exception of several states where the feathered immigrants have not yet reached. The scientist’s intentions were extremely good - to allow city residents to admire all the species of birds mentioned by Shakespeare in his works

Ecosystem and biogeocenosis are practically synonymous. The difference between these concepts lies in the breadth of their meanings. If any territory can be an ecosystem (including the entire biosphere of the planet), then biogeocenosis is characterized by being tied to a specific land area. Thus, biogeocenosis can be considered an ecosystem in a simplified form.

Ecosystems serving humanity

Since the first Homo sapiens landed on the Hawaiian Islands, 71 species of birds have disappeared.

The ability of ecosystems to self-heal and self-regulate – their most valuable quality, both for the entire planet and for humans in particular. Thanks to the so-called services that ecosystems provide us, the world's population is provided not only with food and drinking water, but also with air.

These services are difficult to overestimate, but scientists still made an attempt to calculate and announce the price of the help that ecosystems provided to humanity in 2014. The amount turned out to be more than impressive – 125 trillion US dollars.

What are the services that nature itself so kindly provides to us?

"Providing" services

This includes all the benefits that people from time immemorial have been accustomed to receive from the earth free of charge, that is, for nothing: food (both plant and animal origin), water for drinking and household needs, industrial raw materials and building materials, components for the manufacture of medicines, food additives and cosmetics (plant and animal).

"Auxiliary" services

Being a habitat for many living organisms that are eaten not only by humans, but also by other inhabitants, ecosystems play an important supporting role. They essentially provide food and shelter for millions of living beings, and also ensure their species diversity. This fact is extremely important for the nature of the Earth, since the number of species of animals and plants grown by humans is significantly inferior to the “wild” diversity provided by ecological systems.

"Regulatory" services

Every year, 11 million hectares of tropical forests cease to exist on earth.

Ensuring proper quality of soil, water resources and air, pollination of crops – all this relates to the regulatory function of ecological systems. Absolutely all ecosystems take part in its provision. For example, microorganisms living in wetlands destroy pathogenic flora formed in wastewater, ensuring its filtration and decomposition of waste.

And one more function performed by ecosystems that is difficult to overestimate – release of oxygen into the atmosphere by plants. Forests and other green spaces help break down carbon dioxide into oxygen and carbon, allowing other living things to breathe freely.

"Cultural" services

This category of values ​​that we receive from ecosystems includes our aesthetic pleasure from communicating with nature, our love for our native lands and the countless joys of tourist recreation. After all, if we analyze the list of cultural benefits that travel gives us (contemplation of architecture and picturesque landscapes, acquaintance with the original culture of different peoples), it turns out that most of them are closely related to the natural features of a given territory (climate, soil, landscape, flora and fauna); in other words – with the characteristics of ecosystems existing in a given territory.

UNESCO cultural heritage sites play a special role in the provision of services in this category.

Based on the above facts, the conclusion suggests itself: the importance attached by scientists to ecological systems is in no way exaggerated and the preservation of their integrity today – task number one for all humanity. How to do it? – There is no question more difficult and at the same time simpler than this.

Natural ecosystems, which have not been affected by destructive human activities, make up only 3 - 4% of the land in Europe. Most of these areas are protected areas

You should not try to solve the problem globally, feeling responsible for the entire population of the globe. It’s enough just to reconsider your habits, which can directly or indirectly affect the ecosystems surrounding you personally. The scope of activity in this area is literally limitless. You can at least start sorting the garbage that you throw into a container in the yard and take batteries to a special collection point. And the maximum... well, everyone determines it for themselves –

What does Ecology study?

Ecology

Ernst Haeckel V 1866

List the sections of ecology.

Social ecology is a branch of ecology that studies the relationship between man and the environment.

General ecology is the science of ecosystems, which include living organisms and the nonliving matter with which these organisms constantly interact.

Applied direction - This is a branch of science that deals with the transformation of ecological systems based on the knowledge that humans have. This direction represents the practical part of environmental activities. At the same time, the applied direction contains three more large blocks.

Geoecology-comprehensive science at the intersection of ecology and geography.

an interdisciplinary scientific direction that combines research into the composition, structure, properties, processes, physical and geochemical fields of the Earth’s geospheres as a habitat for humans and other organisms.

What is meant by ecosystem?

Ecological system- a biological system (biogeocenosis), consisting of a community of living organisms (biocenosis), their habitat (biotope), a system of connections that exchanges matter and energy between them.

What are the main blocks of an ecosystem?

A) climatic regime, chemical and physical characteristics of the environment;

inorganic substances (macroelements and microelements) and some organic substances that form soil humus.

B) producers of organic matter are autotrophic organisms, mainly green photosynthetic plants.

D) decomposers - bacteria and fungi that destroy dead bodies or waste organic matter to the state of simple inorganic compounds (water, carbon dioxide, sulfur oxides, etc.)

What is “biocenosis”.

Biocenosis- a historically established set of plants, animals, microorganisms that inhabit an area of ​​land or a body of water (biotope) and are characterized by certain relationships both among themselves and with abiotic environmental factors.

The concept of "population".

A population is a collection of organisms of the same species that live for a long time in one territory (occupying a certain area) and are partially or completely isolated from individuals of other similar groups.

9. List the four environments of life- aquatic, ground-air, soil and organismal. Plants grow in all four habitats.

Bergman's rule.

The rule states that among similar forms of homeothermic (warm-blooded) animals, the largest are those that live in colder climates - in high latitudes or in the mountains.

Allen's rule.

According to this rule, among related forms of homeothermic (warm-blooded) animals leading a similar lifestyle, those that live in colder climates have relatively smaller protruding body parts: ears, legs, tails, etc.

What is meant by "Biosphere".

Biosphere- 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.

The term “biosphere” was introduced in 1875 by E. Suess, an Austrian geologist.

Where are the boundaries of the biosphere?

The boundaries of the Earth's biosphere are drawn along the boundaries of the distribution of living organisms, which means... That its upper boundary passes at the height of the ozone layer at an altitude of 20-25 km. And the lower boundary passes at the depth where organisms cease to be found.

The concept of "noosphere".

The noosphere is the sphere of interaction between society and nature, within the boundaries of which intelligent human activity becomes the determining factor of development.

Social and applied ecology.

Causes

Overgrazing of livestock, destruction of woody vegetation, relief, climate.

What does Ecology study?

Ecology- the science of the interactions of living organisms and their communities with each other and with the environment.

Who coined the term “ecology” and in what year.

The term was first proposed by a German biologist Ernst Haeckel V 1866 year in the book “General morphology of organisms.

123Next ⇒

Ecosystem- the basic concept of ecology. This is a collection of coexisting species of plants, animals, fungi, and microorganisms that interact with each other and with their surrounding environment in such a way that such a community can persist and function over a long period of geological time.

Communities of interacting living organisms are not a random set of species, but a well-defined system, quite stable, connected by numerous internal connections, with a relatively constant structure and an interdependent set of species. Such systems are usually called biotic communities, or biocenoses (from Latin - “biological community”), and systems that include a set of living organisms and their habitat are called ecosystems. The term "biogeocenosis" also means the totality of a biological community and habitat, but in a slightly different context. The biotic community consists of a plant community, an animal community, and a community of microorganisms. All organisms of the Earth and their habitat also represent an ecosystem of the highest rank - the biosphere. The biosphere also has stability and other ecosystem properties.

Ecology examines the interaction of living organisms and inanimate nature. This interaction, firstly, occurs within a certain system (ecological system, ecosystem) and, secondly, it is not chaotic, but organized in a certain way, subject to laws. An ecosystem is a collection of producers, consumers and detritivores that interact with each other and with their environment through the exchange of matter, energy and information in such a way that this single system remains stable over a long period of time. Thus, a natural ecosystem is characterized by three features:

1) an ecosystem is necessarily a collection of living and nonliving components

2) within the ecosystem, a full cycle is carried out, starting with the creation of organic matter and ending with decomposition into inorganic components;

3) the ecosystem remains stable for a long time, which is ensured by a certain structure of biotic and abiotic components.

Examples of natural ecosystems are lake, cave, forest, desert, tundra, ocean, biosphere. As can be seen from the examples, simpler ecosystems are part of more complexly organized ones. At the same time, a hierarchy of organization of systems, in this case environmental, is realized. Thus, the structure of nature should be considered as a systemic whole, consisting of ecosystems nested within one another, the highest of which is a unique global ecosystem - the biosphere.

The concept of ecosystem and biogeocenosis

The term “ecosystem” was first proposed by the English ecologist A. Tansley in 1935. He considered ecosystems as the main structural units of nature on planet Earth.

An ecosystem is a complex of a community of living organisms and their habitat in which the exchange of matter and energy occurs.

Ecosystems do not have a specific dimension. A rotting stump with invertebrate animals, fungi and bacteria inhabiting it is a small-scale ecosystem ( microecosystem). A lake with aquatic and semi-aquatic organisms is a medium-scale ecosystem ( mesoecosystem). And the sea, with its diversity of algae, fish, mollusks, and crustaceans, is a large-scale ecosystem ( macroecosystem).

To designate such systems on homogeneous land areas, the Russian geobotanist V.N. Sukachev proposed the term “biogeocenosis” in 1942.

Biogeocenosis is a historically established set of living (biocenosis) and non-living (biotope) components of a homogeneous land area where the circulation of substances and energy conversion occurs.

As can be seen from the above definition, biogeocenosis includes two structural parts - biocenosis and biotope. Each of these parts consists of certain components that are interconnected.

Biogeocenosis and ecosystem are similar concepts that denote biosystems of the same level of organization. A common feature for these systems is the presence in them of the exchange of matter and energy between living and nonliving components.

However, the above concepts are not synonymous. Ecosystems have varying degrees of complexity, different scales, they can be natural (natural) and artificial (man-made). A drop of water from a puddle with microorganisms, a swamp hummock with its population, a lake, a meadow, a desert and, finally, the biosphere - the ecosystem of the highest rank - can be considered as separate ecosystems.

Biogeocenosis differs from an ecosystem in its territorial limitation and a certain composition of populations (biocenosis). Its boundaries are determined by ground vegetation cover (phytocenosis). A change in vegetation indicates a change in conditions in the biotope and the border with the neighboring biogeocenosis. For example, the transition from woody vegetation to herbaceous vegetation indicates the boundary between forest and meadow biogeocenoses.

Who introduced the concept of “ecosystem” into science?

Biogeocenoses are distinguished only on land.

Consequently, the concept of “ecosystem” is broader than “biogeocenosis”. Any biogeocenosis can be called an ecosystem, but only terrestrial ecosystems can be called a biogeocenosis.

From the point of view of providing nutrients, biogeocenoses are more autonomous (independent of other biogeocenoses) than ecosystems. Each of the stable (existing for a long time) biogeocenoses carries out its own cycle of substances, comparable in nature to the cycle of substances in the biosphere of planet Earth, but only on a much smaller scale. Ecosystems are more open systems. This is another difference between biogeocenoses and ecosystems.

Ecosystem structure

In an ecosystem, species of organisms perform different functions, thanks to which the cycle of substances occurs. Depending on the role that species play in the cycle, they are classified into different functional groups: producers, consumers or decomposers.

Producers(from lat. producens- creator), or manufacturers, are autotrophic organisms that synthesize organic matter from mineral matter using energy. If solar energy is used to synthesize organic matter, then the producers are called photoautotrophs. Photoautotrophs include all green plants, lichens, cyanobacteria, autotrophic protists, green and purple bacteria. Producers that use the energy of chemical reactions of oxidation of inorganic substances to synthesize organic matter are called chemoautotrophs. They are iron bacteria, colorless sulfur bacteria, nitrifying and hydrogen bacteria.

Decomposers(from lat. reducens- returning), or destroyers, - heterotrophic organisms that destroy dead organic matter of any origin to mineral matter.

The resulting mineral substance accumulates in the soil and is subsequently absorbed by producers. In ecology, dead organic matter involved in the decomposition process is called detritus. Detritus- dead remains of plants and fungi, corpses and animal excrement with bacteria contained in them.

Detritivores and decomposers participate in the decomposition process of detritus. Detritivores include wood lice, some mites, millipedes, springtails, carrion beetles, some insects and their larvae, and worms. They consume detritus and, during their life, leave excrement containing organic matter. Fungi, heterotrophic protists, and soil bacteria are considered true decomposers. All representatives of detritivores and decomposers, dying, also form detritus.

The role of decomposers in nature is very great. Without them, dead organic remains would accumulate in the biosphere, and the minerals needed by producers would dry up. And life on Earth in the form we know would cease.

The relationship of functional groups in an ecosystem can be shown in the following diagram.

In an ecosystem with high species diversity, the interchangeability of one species with another can occur without disturbing the functional structure.

An ecosystem is a complex of a community of living organisms and their habitat in which the exchange of matter and energy occurs. Terrestrial ecosystems are called biogeocenoses. Biogeocenosis is a combination of biocenosis and biotope, where the circulation of substances and the transformation of energy takes place. The functional components of an ecosystem are producers, consumers and decomposers.

The term " ecosystem“was first proposed in 1935 by the English ecologist A. Tansley, but, of course, the very idea of ​​an ecosystem arose much earlier. Mention of the unity of organisms and the environment (as well as man and nature) can be found in the most ancient written monuments of history.

Who coined the term “ecology” and in what year.

But a systematic approach to the ecosystem began to appear at the end of the last century. Thus, the German scientist Karl Mobius wrote in 1877 about the community of organisms on an oyster bank as « biocenosis ", and in 1887, the American biologist S. Forbes published his classic work on the lake as " microcosm" Russian and Soviet ecologists made a great contribution to this issue. Thus, the famous scientist V.V. Dokuchaev (18461903) and his student G.F. Morozov, who specialized in forest ecology, attached great importance to the idea of ​​“biocenosis”.

In the domestic literature on ecology, awareness of the insufficiency of the biocenotic approach in solving problems of studying and managing natural systems was manifested in the development by Academician V.N. Sukachev in 1944 of the doctrine of " biogeocenosis ».

Biogeocenosis - a collection over a known area of ​​the earth's surface homogeneous natural phenomena (atmosphere, rock, vegetation, animal life and the world of microorganisms, soil and hydrological conditions), which has the specific interactions of its components and a certain type of exchange of matter and energy among themselves and with other natural phenomena.

The concepts of “ecosystem” and “biogeocenosis” are close to each other, but are not synonymous. According to A. Tansley's definition, ecosystems– these are dimensionless stable systems of living and nonliving components in which external and internal circulation of substances and energy takes place. Thus, an ecosystem is a drop of water with its microbial population, a flower pot, a manned spacecraft, and an industrial city. They do not fall under the definition of biogeocenosis, since they do not have many of the characteristics of this definition. An ecosystem may include several biogeocenoses. Thus, the concept of “ecosystem” is broader than “biogeocoenosis”, that is, any biogeocenosis is an ecological system, but not every ecosystem can be considered a biogeocenosis, and biogeocenoses are purely terrestrial formations that have their own clear boundaries.

After, thanks to the rapid development of radio electronics and computer technology, the general theory of systems was developed, the development of new, quantitative directions – ecology of ecosystems. The question of to what extent ecosystems obey the laws of functioning of integral systems, for example, such as the now well-studied physical systems, and to what extent ecosystems are capable of self-organization, like organisms, remains open to this day, and its study continues.

There are microecosystems (for example, leaf litter of one tree, etc.), mesoecosystems (pond, small grove, etc.), macroecosystems (continent, ocean) and, finally, a global ecosystem - the Earth’s biosphere, which we have already discussed in sufficient detail above (Fig. .37).[...]

In a laboratory microecosystem model, autotrophic and heterotrophic succession can be combined if samples from already developed systems are added to an environment enriched with organic matter. At first, when heterotrophic bacteria “bloom”, the system becomes cloudy, then, when the nutrients and growth substances needed by the algae (in particular, thiamine) enter the environment due to the activity of the bacteria, the system becomes bright green. This, of course, is a good model of artificial sustrophication.[...]

Sometimes ecosystems are classified into microecosystems (for example, the trunk of a fallen tree or a clearing in the forest), mesoecosystems (forest or steppe forest) and macroecosystems (taiga, sea). The ecosystem of the highest (global) level is the Earth's biosphere.[...]

Two types of biological microcosms can be distinguished: 1) microecosystems taken directly from nature by multiple inoculation of the culture medium with samples from different natural habitats, and 2) systems created by combining species grown in “pure” or axenic cultures (free from other organisms) until the desired combination is obtained. Systems of the first type are, in essence, “dismantled” or “simplified” nature, reduced to those microorganisms that can be maintained and function for a long time under the conditions of a vessel, culture medium, light and temperature chosen by the experimenter. Such systems, therefore, usually imitate some specific natural situations. For example, the microcosm shown in Fig. 2.17.5, comes from a treatment pond; in Fig. 2.19 - from a community living on the fallow land. One of the problems encountered when working with such derived ecosystems is that it is difficult to determine their exact species composition, especially bacterial composition (Gorden et al., 1969). The use of derivative or “multiple” systems in ecology began with the work of G. Odum and his students (N. Odum, Hoskins, 1957; Beyers 1963).[...]

The ecosystems existing on Earth are diverse. There are microecosystems (for example, the trunk of a rotting tree), mesoecosystems (forest, pond, etc.), macroecosystems (continent, ocean, etc.) and the global one - the biosphere. [...]

Although direct extrapolation of a small laboratory microecosystem to nature may not be entirely justified, some data suggest that the main trends observed in the laboratory are characteristic of succession on land and in large bodies of water. Seasonal succession often follows the same pattern—following an early-season “bloom” that is characterized by the rapid growth of a few dominant species, by the end of the season a high B/P ratio develops, increased diversity and relative, albeit temporary, persistence as this established in terms of P and R (Margalef, 1963). In open systems at mature stages, the decrease in total, or gross, production observed in a spatially limited microcosm may not occur, but the general pattern of bioenergetic changes in the latter, apparently, well imitates nature.[...]

The problem can also be analyzed experimentally, by creating experimental populations in microecosystems. One such experimental model is shown in Fig. 107. The aquarium fish guppy (Lebisleus reclusidae) was used to simulate a population of commercial fish caught by humans. It can be seen that the maximum sustainable yield was obtained when one third of the population was harvested during each reproductive period, which resulted in a decrease in the equilibrium density to a value that was slightly less than half the density of the unharvested population. The experiment also showed that these relationships are independent of the maximum capacity of the system, which was maintained at three different levels by varying the amount of food.[...]

It is obvious that ecological systems can be of different levels. For example, classical ecosystems can be: microecosystems (for example, a flower pot, a rotting tree trunk, etc.); mesoecosystems (forest, pond, etc.); macroecosystems (ocean, continent, etc.).[...]

The problems associated with direct colony counting are well illustrated by the work of Gorden et al. (1969). IN). Colony count data in table. 65 show that the abundance of Bacillus sp. first increases rapidly and then decreases to a low but constant level. However, direct microscopic counting shows that after 3 days Bacillus sp. form spores and become inactive in this system. In this case, counting live colonies does not provide a clear picture of the entire sequence of events and leads to an overestimation of the number of active cells in the system, since spores of Bacillus sp. germinated and gave rise to colonies in the medium for counting them. [...]

Often, the lack of rank of the concept “ecosystem” creates certain difficulties for characterizing anthropogenic systems. Therefore, it is advisable to distinguish three categories of ecosystems: microecosystems (ecosystem of a stump, anthill, dung heap, etc.); mesoecosystems (an ecosystem within the boundaries of a phytocenosis) and macroecosystems (such as tundra, ocean, etc.).[...]

E. e. With. - a multifaceted concept.

Handout tests on ecology with answers (page 1)

There is a planetary E. e. pp., covering the entire planet Earth; intercontinental E. e. With.; national; E. e. With. territories of the state; regional; local; microecosystems. They differ not only in territory, but also in the set of natural components: vegetation; fauna, including microorganisms; biocenosis; biomass. Between them there is an interchange and interrelation of organic and inorganic substances, components based on the natural Law of balance in nature and the environment.[...]

The basis of environmental education is classroom work, but in no way can it be limited to lessons. Quite accessible to many schools for conducting classes on the topic of nature conservation and introducing children to practical work can be a schoolyard, a plot of natural landscape located near the school, a city park, microecosystems (pond, field, rock dump). At the same time, it is important to ensure that schoolchildren participate in carrying out research and discussing problems.[...]

Let's move on to the most important generalization, namely that negative interactions become less noticeable over time if the ecosystem is sufficiently stable and its spatial structure allows for the mutual adaptation of populations. In model systems of the predator-prey type described by the Lotka-Volterra equation, if additional terms characterizing the action of self-limiting factors of numbers are not introduced into the equation, then the oscillations occur continuously and do not die out (see Lewontin, 1969). Pimentel (1968; see also Pimentel and Stone 1968) showed experimentally that such additional terms may reflect mutual adaptations or genetic feedback. When new cultures were created from individuals that had previously co-existed for two years in a culture where their numbers were subject to significant fluctuations, it turned out that they developed ecological homeostasis, in which each of the populations was “suppressed” by the other to such an extent that it turned out their coexistence is possible at a more stable equilibrium.[...]

Ecosystem sizes vary. Such large terrestrial ecosystems, or macroecosystems, such as tundra, taiga, steppe, desert, are called biomas. Each biome includes a number of smaller, interconnected ecosystems (ranging from a million square kilometers in area to a small area occupied by a forest, meadow, or swamp). There are very small ecosystems, or microecosystems, such as the trunk of a rotting tree, the lower layers of a lake. Clear boundaries between ecosystems are rare. Typically, between ecosystems there is a transition zone with species characteristic of both neighboring systems. Ecosystems are not isolated from each other, but smoothly transition into one another. There is also interaction between different ecosystems, both direct and indirect.[...]

A. Tansley defined the concept of “ecosystem”, although the German K. Mobius, back in 1877, wrote about the community of organisms on a coral reef as a biocenosis. To express such a holistic, as expressed by Yu. Odum (1975), point of view, other terms were previously used, among which should be called the natural complex of V.V. Vernadsky. An ecosystem integrates components into a functional whole. Later they began to distinguish microecosystems, mesoecosystems and macroecosystems, although the understanding of the scope of these divisions may be different among different researchers.[...]

Indeed, taking as a basis the first definition of an ecosystem given in topic 8: “... any continuously changing unity, including...”, we can consider an ecosystem any biocenosis that meets such requirements as the presence of trophic levels, influence on the microclimate, etc. But let’s remember another formulation, which, unlike the first, contains the time factor: “...a historically established system...”. Apparently, it is more correct to consider the “population” of a stump or a complex of saprophagous species living in a cake of manure only as fragments of an ecosystem that exist for a short time. The autonomy of a microecosystem is relative and significantly depends on other fragments of the ecosystem. Based on these considerations, the minimum dimensional unit of an ecosystem should be considered unities larger than microecosystems: meadow, forest, field, lake, etc. [...]

While many ponds and lakes have been well studied as entire ecosystems, rivers have been studied very little in this regard. This situation is explained mainly by the fact that, as will be shown below, rivers are large and incomplete systems. There are some excellent studies on the energetics of food webs in rivers; in these works special attention is paid to fish. A group of researchers studied the Thames in England (see Mann, 1964, 1965, 1969). Since most rivers in the vicinity of cities are heavily polluted at least for some extent, a small book by Haynes (1960) “The Biology of Polluted Waters” is a good reference for beginners. [...]

Currently, the concept of ecosystem - this is one of the most important generalizations of biology - plays a very important role in ecology. This was largely facilitated by two circumstances pointed out by G. A. Novikov (1979): firstly, ecology as a scientific discipline is ripe for this kind of generalizations and they have become vitally necessary, and secondly, now more than ever, issues of protection have arisen biosphere and theoretical justification of environmental measures, which are based primarily on the concept of biotic communities - ecosystems. In addition, according to G. A. Novikov, the spread of the idea of ​​an ecosystem was facilitated by the flexibility of the concept itself, since ecosystems can include biotic communities of any scale with their habitat - from a pond to the World Ocean, and from a stump in the forest to a vast forest area, for example, taiga.[...]

Ecosystem A.

Tensley and biogeocenosis V. N. Sukacheva

Biocenology

Biocenology (from biocenosis and Greek logos - teaching, science) is

1) Biological discipline that studies plant and animal communities in their totality (wildlife), that is, biocenoses, their structure, development, distribution in space and time, origin. The study of communities of organisms in their interaction with inanimate nature is the subject of biogeocenology.

2) The central section of ecology, which studies the patterns of life of organisms in biocenoses, their population structure, energy flows and the circulation of substances. Close to the concept of synecology.

3) The science of biological communities or biocenoses, their composition, structure, internal or biocenotic environment, biotrophic and mediopathic processes occurring in communities, mechanisms of regulation and development (biocenogenesis), productivity, use and protection of communities.

Ecosystem of A. Tansley and biogeocenosis of V. N. Sukachev

Ecosystem Definitions:

· Any unity that includes all organisms in a given area and interacts with the physical environment in such a way that the flow of energy creates a clearly defined trophic structure, species diversity and circulation of substances (exchange of substances and energy between biotic and abiotic parts) within the system (Y. Odum, 1971).

· System of physical-chemical-biological processes (A. Tansley, 1935).

· A community of living organisms together with the nonliving part of the environment in which it is found and all its various interactions (D. F. Owen.).

· Any set of organisms and inorganic components of their environment in which the circulation of substances can take place (V.V. Denisov.).

The concept of “ecosystem” was introduced by the English botanist A. Tansley (1935), who used this term to designate any collection of co-living organisms and their environment.

According to modern ideas, ecosystem as the main structural unit of the biosphere, it is an interconnected single functional set of living organisms and their habitat, or a balanced community of living organisms and the surrounding inanimate environment. This definition emphasizes the presence of relationships, interdependence, cause-and-effect relationships between the biological community and the abiotic environment, combining them into a functional whole. Biologists believe that an ecosystem is the totality of all populations of different species living in a common territory, together with the inanimate environment that surrounds them.

The scale of ecosystems is different: microsystems (for example, a swamp hummock, a tree, a moss-covered stone or stump, a flower pot, etc.), mesoecosystems (lake, swamp, sand dune, forest, meadow, etc.), macroecosystems ( continent, ocean, etc.). Consequently, there is a peculiar hierarchy of macro-, meso- and microsystems of different orders.

The biosphere is an ecosystem of the highest rank, including, as already noted, the troposphere, hydrosphere and the upper part of the lithosphere within the “field” of the existence of life. It has an enormous diversity of communities, in the structure of which complex combinations of plants, animals and microorganisms with different modes of life are found. In this mosaic, terrestrial and aquatic ecosystems are primarily distinguished. According to what was formulated by V.V. Dokuchaev (1896), according to the law of geographic zonation, various natural communities are naturally distributed on the earth’s surface, which together form a single ecosystem of our planet. Within vast territories, or zones, natural conditions retain common features, changing from zone to zone. Climate, vegetation and animals are distributed on the earth's surface in a strictly defined order. And since soil-forming agents, in their distribution subject to known laws, are distributed among zones, then the result of their activity - soil - should be distributed around the globe in the form of certain zones, running more or less parallel to latitudinal circles. The replacement of the Arctic and Subarctic by tundra, tundra by forest-tundra, taiga-forest zone by forest-steppe and steppe, and then by semi-desert spaces on the territory of Russia is clearly visible. The replacement of lowland ecosystems with mountain ones is also noticeable (Caucasus, Ural, Altai, etc.). In all these macroecosystems of different orders, one should consider only similar types of communities that form under similar climatic conditions in different parts of the planet, and not the species composition and populations of macroecosystems. In addition, the differentiation of ecosystems is expressed depending on local conditions (geological factors, relief, parent rocks, soils, etc.), where it is already possible to consider and evaluate populations of different species and the species composition of ecological systems. All this diversity of biosphere ecosystems, especially planetary (land and ocean), as well as provincial and zonal, must be studied by comparing their productivity.

The following hierarchy has been established for terrestrial ecosystems: biosphere - land ecosystem - climatic zone - bioclimatic region - natural landscape zone - natural (landscape) district - natural (landscape) region - natural (landscape) subdistrict - biogeocenotic complex - ecosystem.

Ecosystems modified by human activity are called agroecosystems(shelter forest belts, fields occupied by agricultural crops, orchards, vegetable gardens, vineyards, etc.). They are based on cultural phytocenoses - perennial and annual grasses, grains and other agricultural crops. They receive additional energy in the form of soil cultivation, application of fertilizers, irrigation water, pesticides and other land reclamation, which significantly transforms the soil, changes the species composition, structure of flora and fauna. As a result, instead of stable ecosystems, less stable ones are formed. Energy subsidies for new agroecosystems and the possibility of reclamation of natural ecosystems should be based on the norms of the ratio of arable land, meadows, forests and water in accordance with soil, climatic and economic conditions, as well as on the laws, rules and principles of ecology.

Biogeocenosis (V.N. Sukachev, 1944) is an interdependent complex of living and inert components interconnected by metabolism and energy.

V.N. Sukachev (1972) proposed biogeocenosis as a structural unit of the biosphere. Biogeocenoses - natural formations with clear boundaries, consisting of a collection of living beings (biocenoses) occupying a certain place. For aquatic organisms it is water, for terrestrial organisms it is soil and atmosphere.

The concepts of “biogeocenosis” and “ecosystem” are to some extent unambiguous, but they do not always coincide in scope. Ecosystem is a broad concept; an ecosystem is not associated with a limited area of ​​the earth's surface. This concept applies to all stable systems of living and nonliving components, where external and internal circulation of substances and energy occurs. Thus, ecosystems include a drop of water with microorganisms, an aquarium, a flower pot, an aeration tank, a biofilter, and a spaceship. They cannot be biogeocenoses. An ecosystem may include several biogeocenoses (for example, biogeocenoses of a district, province, zone, soil-climatic region, belt, continent, ocean and biosphere as a whole).

Thus, not every ecosystem can be considered a biogeocenosis, while every biogeocenosis is an ecological system.

The concept of Biogeocenosis was introduced by V. N. Sukachev (1940), which was a logical development of the ideas of Russian scientists V. V. Dokuchaev, G. F. Morozov, G. N. Vysotsky and others about the connections between living and inert bodies of nature and the ideas of V. I. Vernadsky about the planetary role of living organisms. Biogeocenosis in the understanding of V.N. Sukachev is close to the ecosystem in the interpretation of the English phytocenologist A.

Who introduced the term ecosystem into science?

Tansley, but is distinguished by the definiteness of its volume. Biogeocenosis is an elementary cell of the biogeosphere, understood within the boundaries of specific plant communities, while an ecosystem is a dimensionless concept and can cover a space of any extent - from a drop of pond water to the biosphere as a whole.

Ecological succession (F. Clements)

Succession (from Latin succesio - continuity, inheritance) is a consistent irreversible and natural change of one biocenosis (phytocenosis, microbial community, biogeocenosis, etc.) to another in a certain area of ​​the environment over time.

The theory of succession was initially developed by geobotanists, but then began to be widely used by other ecologists. One of the first to develop the theory of succession was F. Clements and developed it by V. N. Sukachev, and then by S. M. Razumovsky.

The term was introduced by F. Clements to designate communities that replace each other over time, forming a succession series (series) where each previous stage (serial community) forms the conditions for the development of the next one. If no events causing a new succession occur, then the series ends with a relatively stable community that has a balanced exchange given the given environmental factors. F. Clements called such a community a climax. The only sign of menopause in the sense of Clements-Razumovsky is the absence of internal reasons for change. The time of existence of a community cannot in any case be one of the indicators.

Although the terms introduced by Clements are widely used, there are two fundamentally different paradigms within which the meaning of these terms is different: continualism and structuralism. Supporters of structuralism develop Clements' theory, supporters of continuum, in principle, reject the reality of communities and successions, considering them stochastic phenomena and processes (polyclimax, climax-continuum). The processes occurring in the ecosystem in this case are simplified to the interaction of species encountered at random and the abiotic environment.

The continuum paradigm was first formulated by the Soviet geobotanist L. G. Ramensky (1884-1953) and, independently of him, by the American geobotanist G. Gleason (1882-1975).

Bibliography

1. Razumovsky S. M. Patterns of biocenosis dynamics. M.: Nauka, 1981.

2. http://ru.wikipedia.org/wiki/Succession

3. http://dic.academic.ru/dic.nsf/ecolog/1429/Biocenology

4. Rosenberg G. S., Mozgovoy D. P., Gelashvili D. B. Ecology. Elements of theoretical structures of modern ecology. Samara: SamSC RAS, 1999. 397 p.