Preliminary remarks.

1. Living organisms belong to the category of super-complex systems, in the study of which certain simplifications are inevitable.

2. All factors influencing a given organism at a given time act simultaneously. Reasoning about the influence of one (separately taken) environmental factor is a simplification that allows you to better understand individual patterns. It would be ideal to continuously record the values ​​of all environmental factors and the response of a living system (organism).

3. The simplest option is to measure the values ​​of a certain vital sign(P g) of an organism under experimental conditions with different values ​​of one studied environmental factor (F e) and a constant (optimal) value of all other environmental factors: P f = f(F e). Such experiments are called single-factor experiments; they must respect the "rule of single difference" between the variants of experience.

Productivity, biomass growth rate, respiration intensity, metabolic rate, physical activity and much more can serve as indicators of the vital activity of an organism. Indicators of the "well-being and prosperity" of a species (population) - birth rate, productivity, abundance, survival rate, etc.

For example, the quantitative dependence of the net primary productivity of a plant (NPP) on air temperature (t in), such as NPP = f (t in), can be obtained under conditions of an active experiment. To do this, plants are grown at different air temperatures (experimental options), making sure that the values ​​of other environmental factors (moisture supply, nutrients, etc.) remain the same and optimal in all options (single difference rule).

« The law of the minimum "J. Liebig

“The idea that the endurance of an organism is determined by the weakest link in the chain of its ecological needs was first clearly shown in 1840 by J. Liebig,” says J. Odum. Justus Liebig (1803 - 1873), an outstanding German chemist, one of the founders of agricultural chemistry, the author of the theory of mineral nutrition of plants. On the basis of numerous experiments, J. Liebig (1840) made the most important scientific generalizations, essentially formulated the first ecological laws long before the appearance of ecology itself. He found that the yield of plants depends on the element of mineral nutrition that is in the soil at a relative minimum (in relation to the needs of the plant).

« Law" minimum(J. Liebig, 1840): "The substance, which is at a minimum, controls the crop and determines the size and stability of the crop over time."

For example, let the soil contain the optimal amount of moisture, phosphorus, potassium, and all other elements of the mineral nutrition of plants, with the exception of nitrogen, which is not enough. Then the nitrogen content will be limit plant productivity. If, under these conditions, the amount of nitrogen fertilizers applied is consistently increased (on various experimental plots), then the yield of plants will also increase in the same sequence (up to a certain level).

Yu. Liebig also found that the yield can be limited, limited not only by those nutrients that are required by plants in large quantities (N, P, K, etc.), but also by those that are needed in very small quantities (microelements). In the modern wording, this provision is known as " law of equivalence of the main environmental factors».

No less, and perhaps even more important for ecology, is the theory of mineral nutrition of plants developed by J. Liebig, which played a huge role in shaping ideas about the interaction of living and non-living things at the level of atoms of chemical elements. We will not specifically dwell on those numerous refinements and additions to the "law of the minimum", which have appeared over more than a century and a half of the development of science - this will be clear from the following presentation.

W. Shelford's Law of Tolerance

Numerous experiments have shown that in relation to the action of many, but by no means all, environmental factors on the body, general patterns are observed:

1) the vital activity of an organism can be limited not only by a deficiency, but also by an “excess” of the impact of a certain factor;

2) the vital activity of an organism (species) is possible only in a certain range of factor values ​​(from and to);

3) with the constancy of other factors, there is a “best”, optimal value for the organism of the studied factor;

4) species of organisms are strictly individual in relation to the action of environmental factors - the optimum for one species may be unbearable for another.

These general patterns can be combined into " optimum rule or the so-called law of tolerance". Usually, the formulation of the law of tolerance is associated with the name of the American ecologist W. Shelford, although it is simply impossible to establish authorship in this case.

Tolerance(from lat. tolerance- patience, tolerance) - the endurance of an organism (species) to the action of a given environmental factor. Synonym: ecological valence.

Law of Tolerance(W. Shelford, 1913) – the limiting factor for the prosperity of an organism can be both a minimum (deficiency) and a maximum (excess) of environmental impact, the range between which determines the amount of endurance (tolerance) of the organism to this factor.

Ecological valence- the degree of adaptability of the species to changes in environmental conditions - the same as tolerance.

The limits of tolerance of an organism to the action of a given environmental factor are determined in the so-called stressful experiments (stress experiments are called because in them it is necessary to achieve the death of the organism). If you present the results of the experiment in the form of a graph, you get the famous bell-shaped tolerance curve (Fig. 1.1).

On the tolerance curve (Fig. 1.1) allocate: ecological minimum("death from lack"), ecological maximum("death by excess") and optimum(best), as well as zone (range) normal life, optimum zone and zones oppression(stress) .

The range of factor values ​​between the ecological minimum and maximum - tolerance range, (limits of tolerance of a species, limits of endurance of a species to the action of a given environmental factor) is indicated by prefixes:

evry- wide and steno- narrow.

For example, a eurythermal species (tolerates fluctuations in environmental temperature over a wide range) or a stenothermic species (can exist only with slight temperature fluctuations near the optimum).

Common names are:

stenothermic - eurythermal (in relation to temperature);

stenohydric - euryhydric (in relation to water);

stenohaline - euryhaline (in relation to salinity);

stenophage - euryphage (in relation to food);

stenobiont - eurybiont (in relation to the habitat).

To characterize organisms that have a narrow range of tolerance to certain environmental factors ( steno-), often use endings: ... Phil- loves or... fob- "does not love". For example, stenothermic and cryophilic species ( cryo- cold).

Rice. 1.1. General view (diagram) of the tolerance curve.

Laws of ecology— general patterns and principles of interaction between human society and the natural environment.

The significance of these laws lies in the regulation of the nature and direction of human activity within ecosystems of various levels. Among the laws of ecology formulated by different authors, the most famous are the four aphorisms of the American environmental scientist Barry Commoner (1974):

• "everything is connected to everything"(the law of the universal connection of things and phenomena in nature);
• "everything has to go somewhere"(the law of conservation of mass of matter);
• "nothing comes for free"(about the price of development);
• "nature knows best"(about the main criterion of evolutionary selection).

From the law of the universal connection of things and phenomena in nature("everything is connected with everything") several consequences follow:

• law of large numbers - the cumulative action of a large number of random factors leads to a result that is almost independent of chance, i.e. having a systemic character. Thus, myriads of bacteria in soil, water, bodies of living organisms create a special, relatively stable microbiological environment necessary for the normal existence of all living things. Or another example: the random behavior of a large number of molecules in a certain volume of gas determines quite definite values ​​of temperature and pressure;
• principle of Le Chatelier (Brown) - when an external action brings the system out of a state of stable equilibrium, this equilibrium shifts in the direction in which the effect of the external action decreases. At the biological level, it is realized in the form of the ability of ecosystems to self-regulate;
• law of optimality- any system functions with the greatest efficiency in some spatio-temporal limits characteristic of it;
• any systemic changes in nature have a direct or indirect impact on a person - from the state of the individual to complex social relations.

From law of conservation of mass of matter(“everything has to go somewhere”) at least two postulates of practical importance follow:

Barry Commoner writes “... the global ecosystem is a single entity within which nothing can be gained or lost and which cannot be subject to universal improvement; everything that has been extracted from it by human labor must be replaced. Payment on this bill cannot be avoided; it can only be delayed. The current environmental crisis suggests that the delay has been very long.”

Principle "nature knows best" determines, first of all, what can and what should not take place in the biosphere. Everything in nature - from simple molecules to humans - has passed the most severe competition for the right to exist. Currently, the planet is inhabited by only 1/1000 species of plants and animals tested by evolution. The main criterion for this evolutionary selection is incorporation into the global biotic cycle., filling of all ecological niches. Any substance produced by organisms must have an enzyme that decomposes it, and all decay products must again be involved in the cycle. With every biological species that violated this law, evolution parted sooner or later. Human industrial civilization grossly violates the isolation of the biotic circulation on a global scale, which cannot go unpunished. In this critical situation, a compromise must be found, which can only be done by a person who has a mind and a desire for this.

In addition to the formulations of Barry Commoner, modern ecologists have deduced another law of ecology - "there is not enough for everyone" (the law of limited resources). Obviously, the mass of nutrients for all forms of life on Earth is finite and limited. It is not enough for all representatives of the organic world appearing in the biosphere, therefore, a significant increase in the number and mass of any organisms on a global scale can occur only due to a decrease in the number and mass of others. The English economist T.R. Malthus (1798), who tried to justify the inevitability of social competition with this. In turn, Charles Darwin borrowed from Malthus the concept of "struggle for existence" to explain the mechanism of natural selection in living nature.

Law of limited resources- the source of all forms of competition, rivalry and antagonism in nature and, unfortunately, in society. And no matter how much they consider class struggle, racism, interethnic conflicts to be purely social phenomena, they all have their roots in intraspecific competition, which sometimes takes much more cruel forms than in animals.

The essential difference is that in nature, as a result of competitive struggle, the best survive, but in human society this is by no means the case.

A generalized classification of environmental laws was presented by the famous Soviet scientist N.F. Reimers. They are given the following statements:

• law of social and ecological balance(the need to maintain a balance between the pressure on the environment and the restoration of this environment, both natural and artificial);
• principle of cultural development management(imposing restrictions on extensive development, taking into account environmental restrictions);
• rule of socio-ecological substitution(the need to identify ways to replace human needs);
• law of socio-ecological irreversibility(the impossibility of turning the evolutionary movement back, from complex forms to simpler ones);
• law of the noosphere Vernadsky (the inevitability of the transformation of the biosphere under the influence of thought and human labor into the noosphere - the geosphere, in which the mind becomes dominant in the development of the "man-nature" system).

Compliance with these laws is possible if humanity realizes its role in the mechanism of maintaining the stability of the biosphere. It is known that in the process of evolution only those species are preserved that are able to ensure the stability of life and the environment. Only man, using the power of his mind, can direct the further development of the biosphere along the path of preserving wildlife, preserving civilization and humanity, creating a more just social system, moving from the philosophy of war to the philosophy of peace and partnership, love and respect for future generations. All these are components of a new biospheric worldview, which should become universal.

Laws and principles of ecology

Law of the Minimum

In 1840 Y. Liebig found that the harvest is often limited not by those nutrients that are required in large quantities, but by those that are needed a little, but which are also scarce in the soil. The law he formulated read: “The crop is controlled by the substance that is at a minimum, the magnitude and stability of the latter in time is determined.” Subsequently, a number of other factors were added to the nutrients, such as temperature. The operation of this law is limited by two principles. Liebig's first law is strictly valid only under stationary conditions. A more precise formulation: "in a stationary state, the limiting substance will be the substance whose available quantities are closest to the required minimum." The second principle concerns the interaction of factors. A high concentration or availability of a certain substance can alter the intake of a minimal nutrient. The following law is formulated in ecology itself and generalizes the law of the minimum.

Law of Tolerance

This law is formulated as follows: the absence or impossibility of developing an ecosystem is determined not only by a deficiency, but also by an excess of any of the factors (heat, light, water). Consequently, organisms are characterized by both an ecological minimum and a maximum. Too much of a good thing is also bad. The range between the two values ​​is the limits of tolerance, in which the body normally responds to the influence of the environment. The law of tolerance proposed W. Shelford in 1913. We can formulate a number of proposals supplementing it.

• Organisms can have a wide range of tolerance for one factor and a narrow one for another.
• Organisms with a wide range of tolerance to all factors are usually the most widely distributed.
• If conditions for one environmental factor are not optimal for the species, then the range of tolerance for other environmental factors may narrow.
• In nature, organisms very often find themselves in conditions that do not correspond to the optimal value of one or another factor determined in the laboratory.
• The breeding season is usually critical; during this period, many environmental factors often turn out to be limiting.

Living organisms change environmental conditions in order to weaken the limiting influence of physical factors. Species with a wide geographical distribution form populations adapted to local conditions, which are called ecotypes. Their optima and tolerance limits correspond to local conditions.

General concept of limiting factors

The most important factors on land are light, temperature, and water (precipitation), while in the sea, light, temperature, and salinity. These physical conditions of existence may be limiting and influencing favorably. All environmental factors depend on each other and act in concert. Other limiting factors include atmospheric gases (carbon dioxide, oxygen) and biogenic salts. Formulating the "law of the minimum", Liebig had in mind the limiting effect of vital chemical elements present in the environment in small and intermittent quantities. They are called trace elements and include iron, copper, zinc, boron, silicon, molybdenum, chlorine, vanadium, cobalt, iodine, sodium. Many trace elements, like vitamins, act as catalysts. Phosphorus, potassium, calcium, sulfur, magnesium, required by organisms in large quantities, are called macronutrients. An important limiting factor in modern conditions is environmental pollution. The main limiting factor for Y. Odumu, - dimensions and quality oikosa", or our " natural home, and not just the number of calories that can be squeezed out of the ground. The landscape is not only a warehouse, but also the house in which we live. “The goal should be to keep at least a third of all land as protected open space. This means that a third of our entire habitat should be national or local parks, reserves, green areas, wilderness areas, etc.” The territory required by one person, according to various estimates, ranges from 1 to 5 hectares. The second of these figures exceeds the area that now falls on one inhabitant of the Earth.

The population density is approaching one person per 2 hectares of land. Only 24% of the land is suitable for agriculture. While as little as 0.12 hectares can provide enough calories to sustain one person, a healthy diet with plenty of meat, fruits and greens requires about 0.6 hectares per person. In addition, about 0.4 hectares are required for the production of various types of fibers (paper, wood, cotton) and another 0.2 hectares for roads, airports, buildings, etc. Hence the concept of the "golden billion", according to which the optimal population is 1 billion people, and therefore, there are already about 5 billion "extra people". Man, for the first time in his history, faced limiting rather than local limitations. Overcoming the limiting factors requires huge expenditures of matter and energy. Doubling the yield requires a tenfold increase in the amount of fertilizer, pesticides and power (animals or machines). Population size is also a limiting factor.

Law of competitive exclusion

This law is formulated as follows: two species occupying the same ecological niche cannot coexist in one place indefinitely.

Which species wins depends on external conditions. In similar conditions, everyone can win. An important circumstance for victory is the rate of population growth. The inability of a species to biotic competition leads to its displacement and the need to adapt to more difficult conditions and factors.

The law of competitive exclusion can also work in human society. The peculiarity of its action at the present time is that civilizations cannot disperse. They have nowhere to leave their territory, because in the biosphere there is no free space for settling and there is no excess of resources, which leads to an aggravation of the struggle with all the ensuing consequences. We can talk about ecological rivalry between countries and even ecological wars or wars caused by ecological reasons. At one time, Hitler justified the aggressive policy of Nazi Germany by the struggle for living space. Resources of oil, coal, etc. and then they were important. They have even greater weight in the 21st century. In addition, the need for territories for the disposal of radioactive and other waste was added. Wars—hot and cold—take on an ecological dimension. Many events in modern history, such as the collapse of the Soviet Union, are perceived in a new way, if you look at them from an ecological perspective. One civilization can not only conquer another, but use it for selfish purposes from an ecological point of view. This will be ecological colonialism. This is how political, social and environmental issues intertwine.

Basic law of ecology

One of the main achievements of ecology was the discovery that not only organisms and species develop, but also. The sequence of communities that replace each other in a given area is called succession. Succession occurs as a result of a change in the physical environment under the action of the community, i.e. controlled by him.

High productivity gives low reliability - another formulation of the basic law of ecology, from which the following rule follows: "Optimal efficiency is always less than maximum." Diversity, in accordance with the basic law of ecology, is directly related to sustainability. However, it is not yet known to what extent this relationship is causal.

Some other laws and principles important for ecology.

Law of emergence: the whole always has special properties that its part does not have.

Law of Necessary Variety: the system cannot consist of absolutely identical elements, but can have a hierarchical organization and integrative levels.

Law of irreversibility of evolution: an organism (population, species) cannot return to its previous state, realized in the series of its ancestors.

The Law of Complication of Organization: the historical development of living organisms leads to the complication of their organization through the differentiation of organs and functions.

biogenetic law(E. Haeckel): the ontogenesis of an organism is a brief repetition of the phylogenesis of a given species, i.e. the individual in his development repeats in short the historical development of his species.

The law of uneven development of parts of the system: systems of one level of the hierarchy do not develop strictly synchronously, while some reach a higher stage of development, others remain in a less developed state. This law is directly related to the law of necessary variety.

The Law of Preservation of Life: life can exist only in the process of movement through the living body of the flow of substances, energy, information.

The principle of maintaining order(Y. Prigozhy): in open systems, the entropy does not increase, but decreases until the minimum constant value is reached, which is always greater than zero.

Le Chatelier-Brown principle: with an external influence that brings the system out of a state of stable equilibrium, this equilibrium is shifted in the direction in which the effect of the external influence is weakened.

Energy Saving Principle(L. Onsager): with the probability of the development of the process in a certain set of directions allowed by the principles of thermodynamics, the one that provides a minimum of energy dissipation is realized.

Law of maximization of energy and information: the best chance for self-preservation has a system that is most conducive to the receipt, production and efficient use of energy and information; the maximum intake of a substance does not guarantee the system success in the competitive struggle.

The law of system development at the expense of the environment: any system can develop only through the use of the material, energy and information capabilities of its environment; absolutely isolated self-development is impossible.

Schrödinger's rule"about nutrition" of the organism with negative entropy: the orderliness of the organism is higher than the environment, and the organism gives more disorder to this environment than it receives. This rule correlates with Prigogine's principle of maintaining order.

Evolution Acceleration Rule: with the increasing complexity of the organization of biosystems, the duration of the existence of a species is on average reduced, and the rate of evolution increases. The average lifespan of a bird species is 2 million years, and that of a mammal species is 800,000 years. The number of extinct species of birds and mammals in comparison with their total number is large.

Law of Relative Independence of Adaptation: high adaptability to one of the environmental factors does not give the same degree of adaptation to other living conditions (on the contrary, it can limit these possibilities due to the physiological and morphological characteristics of organisms).

Principle of minimum population size: there is a minimum population size below which population size cannot fall.

The rule of representation of the genus by one species: in homogeneous conditions and in a limited area, a taxonomic genus, as a rule, is represented by only one species. Apparently, this is due to the proximity of the ecological niches of species of the same genus.

The law of depletion of living matter in its island concentrations(G.F. Hilmi): “An individual system operating in an environment with a level of organization lower than the level of the system itself is doomed: gradually losing its structure, the system will dissolve in the environment after a while.” This leads to an important conclusion for human environmental activities: the artificial preservation of small-sized ecosystems (in a limited area, for example, a reserve) leads to their gradual destruction and does not ensure the conservation of species and communities.

Energy Pyramid Law(R. Lindeman): from one trophic level of the ecological pyramid, on average, about 10% of the energy received at the previous level passes to another, higher level. The reverse flow from higher to lower levels is much weaker - no more than 0.5-0.25%, and therefore it is not necessary to talk about the energy cycle in the biocenosis.

The rule of obligation to fill ecological niches: an empty ecological niche is always and necessarily naturally filled (“nature does not tolerate emptiness”).

Ecosystem formation principle: long-term existence of organisms is possible only within the framework of ecological systems, where their components and elements complement each other and are mutually adapted. From these environmental laws and principles, some conclusions follow that are fair for the “man-environment” system. They belong to the type of law of restriction of diversity, i.e. impose restrictions on human activities to transform nature.

boomerang law: everything that is extracted from the biosphere by human labor must be returned to it.

Law of irreplaceability of the biosphere: the biosphere cannot be replaced by an artificial environment, just as, say, new types of life cannot be created. A person cannot build a perpetual motion machine, while the biosphere is practically a "perpetual" motion machine.

The law of pebbled skin: the global initial natural resource potential is continuously depleted in the course of historical development. This follows from the fact that there are currently no fundamentally new resources that could appear. For the life of each person, 200 tons of solid substances are needed per year, which he, with the help of 800 tons of water and an average of 1000 W of energy, turns into a useful product for himself. All this man takes from what is already in nature.

Event remoteness principle: descendants will come up with something to prevent possible negative consequences. The question of how much the laws of ecology can be transferred to the relationship of man with the environment remains open, since man differs from all other species. For example, in most species, the rate of population growth decreases with increasing population density; in humans, on the contrary, population growth in this case accelerates. Some of the regulatory mechanisms of nature are absent in humans, and this may serve as an additional reason for technological optimism in some, and for environmental pessimists to testify to the danger of such a catastrophe, which is impossible for any other species.

TOPIC 2. BASIC LAWS AND PRINCIPLES OF ENVIRONMENT

The task of ecology, like any other science, is to search for the laws of functioning and development of a given area of ​​reality. Historically, the first for ecology was the law establishing the dependence of living systems on factors limiting their development (the so-called limiting factors).

2.1. Law of the Minimum

J. Liebig in 1840 found that the grain yield is often limited not by those nutrients that are required in large quantities, but by those that are needed in small quantities, but which are scarce in the soil. The law he formulated read: "The substance, which is at a minimum, controls the crop and determines the magnitude and stability of the latter in time." Subsequently, a number of other factors were added to the nutrients, such as temperature.

The operation of this law is limited by two principles. First, Liebig's law is strictly applicable only under steady state conditions. A more precise formulation: "in a stationary state, the limiting substance will be the substance whose available quantities are closest to the required minimum." The second principle concerns the interaction of factors. A high concentration or availability of a certain substance can alter the intake of a minimal nutrient. The body sometimes replaces one, deficient substance with another, available in excess.

The following law is formulated in ecology itself and generalizes the law of the minimum.

2.2. Law of Tolerance

It is formulated as follows: the absence or impossibility of developing an ecosystem is determined not only by a deficiency, but also by an excess of any of the factors (heat, light, water). Consequently, organisms are characterized by both an ecological minimum and a maximum. Too much of a good thing is also bad. The range between the two values ​​is the limits of tolerance, in which the body normally responds to the influence of the environment. The law of tolerance was proposed by W. Shelford in 1913. We can formulate a number of proposals that complement it:

1. Organisms can have a wide range of tolerance for one factor and a narrow range for another.

2. Organisms with a wide range of tolerance to all factors are usually the most widely distributed.

3. If the conditions for one ecological factor are not optimal for the species, then the range of tolerance to other environmental factors may narrow.

4. In nature, organisms very often find themselves in conditions that do not correspond to the optimal value of one or another factor, determined in the laboratory.

5. The breeding season is usually critical; during this period, many environmental factors often turn out to be limiting.

Living organisms change environmental conditions in order to weaken the limiting influence of physical factors. Species with a wide geographical distribution form populations adapted to local conditions, which are called ecotypes. Their optima and tolerance limits correspond to local conditions. Depending on whether ecotypes are genetically fixed, one can speak of the formation of genetic races or of simple physiological acclimation.

2.3. General concept of limiting factors

The most important factors on land are light, temperature, and water (precipitation), while in the sea, light, temperature, and salinity. These physical conditions of existence can be limiting and influencing favorably. All environmental factors depend on each other and act in concert.

Other limiting factors include atmospheric gases (carbon dioxide, oxygen) and biogenic salts. Formulating the "law of the minimum", Liebig had in mind the limiting effect of vital chemical elements present in the environment in small and intermittent quantities. They are called trace elements and include iron, copper, zinc, boron, silicon, molybdenum, chlorine, vanadium, cobalt, iodine, sodium. Many trace elements, like vitamins, act as catalysts. Phosphorus, potassium, calcium, sulfur, magnesium, required by organisms in large quantities, are called macronutrients.

An important limiting factor in modern conditions is environmental pollution. It occurs as a result of the introduction into the environment of substances that either did not exist in it (metals, new synthesized chemicals) and which do not decompose at all, or that exist in the biosphere (for example, carbon dioxide), but introduced in excessively large quantities that do not allow process them naturally. Figuratively speaking, pollutants are resources in the wrong place. Pollution leads to an undesirable change in the physical, chemical and biological characteristics of the environment, which has an adverse effect on ecosystems and humans. The price of pollution is health, the price, in the literal sense, of the cost of its restoration. Pollution is increasing both as a result of the growth of the population and its needs, and as a result of the use of new technologies that serve these needs. It is chemical, thermal, noise.

The main limiting factor, according to J. Odum, is the size and quality of "oikos", or our "natural abode", and not just the number of calories that can be squeezed out of the earth. The landscape is not only a warehouse, but also the house in which we live. “The aim should be to keep at least a third of all land as protected open space. This means that a third of our entire habitat should be national or local parks, reserves, green areas, wilderness areas, etc.” (Yu. Odum. Basics ... p. 541). Restriction of land use is analogous to a natural regulatory mechanism called territorial behavior. Many animal species use this mechanism to avoid crowding and the stress it causes.

The territory required by one person, according to various estimates, ranges from 1 to 5 hectares. The second of these figures exceeds the area that now falls on one inhabitant of the Earth. The population density is approaching one person per 2 hectares of land. Only 24% of the land is suitable for agriculture. “While an area of ​​just 0.12 hectares can provide enough calories to support the existence of one person, about 0.6 hectares per person is needed for a nutritious diet with lots of meat, fruits and greens. In addition, about 0.4 hectares are needed for the production of various types of fibers (paper, wood, cotton) and another 0.2 hectares for roads, airports, buildings, etc.” (Yu. Odum. Basics ... p. 539). Hence the concept of the "golden billion", according to which the optimal population is 1 billion people, and therefore, there are already about 5 billion "extra people". Man, for the first time in his history, faced limiting rather than local limitations.

Overcoming the limiting factors requires huge expenditures of matter and energy. Doubling the yield requires a tenfold increase in the amount of fertilizer, pesticides and power (animals or machines).

Population size is also a limiting factor. This is summarized in Ollie's principle: "the degree of aggregation (as well as overall density) at which optimal population growth and survival is observed varies with species and conditions, so both 'underpopulation' (or lack of aggregation) and overpopulation may have a limiting effect. Some ecologists believe that Ollie's principle applies to humans as well. If so, then there is a need to determine the maximum size of cities that are rapidly growing at the present time.

2.4. Law of competitive exclusion

This law is formulated as follows: two species occupying the same ecological niche cannot coexist in one place indefinitely. Which species wins depends on external conditions. In similar conditions, everyone can win. An important circumstance for victory is the rate of population growth. The inability of a species to biotic competition leads to its displacement and the need to adapt to more difficult conditions and factors.

The law of competitive exclusion can also work in human society. The peculiarity of its action at the present time is that civilizations cannot disperse. They have nowhere to leave their territory, because in the biosphere there is no free space for settling and there is no excess of resources, which leads to an aggravation of the struggle with all the ensuing consequences. We can talk about ecological rivalry between countries and even ecological wars or wars caused by ecological reasons. At one time, Hitler justified the aggressive policy of Nazi Germany by the struggle for living space. Resources of oil, coal, etc. were important even then. They will have even greater weight in the 21st century. In addition, the need for territories for the disposal of radioactive and other waste was added. Wars - hot and cold - take on an ecological dimension. Many events in modern history, such as the collapse of the Soviet Union, are perceived in a new way, if you look at them from an ecological perspective. One civilization can not only conquer another, but use it for selfish purposes from an ecological point of view. This will be ecological colonialism. This is how political, social and environmental issues intertwine.

2.5. Basic law of ecology

One of the main achievements of ecology was the discovery that not only organisms and species develop, but also ecosystems. The sequence of communities that replace each other in a given area is called succession. Succession occurs as a result of a change in the physical environment under the action of the community, that is, it is controlled by it. Substitution of species in ecosystems is caused by the fact that populations, seeking to modify the environment, create conditions favorable for other populations; this continues until an equilibrium is reached between the biotic and abiotic components. The development of ecosystems is in many respects similar to the development of an individual organism and, at the same time, similar to the development of the biosphere as a whole.

Succession in the energetic sense is associated with a fundamental shift in the flow of energy towards an increase in the amount of energy aimed at maintaining the system. Succession consists of stages of growth, stabilization and menopause. They can be distinguished on the basis of the productivity criterion: at the first stage, production grows to a maximum, at the second it remains constant, at the third it decreases to zero as the system degrades.

Most interesting is the difference between growing and mature systems, which can be summarized in the following table.

Table 1Differences between stages of succession

Pay attention to the inverse relationship between entropy and information, and also to the fact that the development of ecosystems is in the direction of increasing their sustainability, achieved through increased diversity. Extending this conclusion to the entire biosphere, we get the answer to the question why 2 million species are needed. One can think (as it was believed before the emergence of ecology) that evolution leads to the replacement of some less complex species by others, up to man as the crown of nature. Less complex types, having given way to more complex ones, become unnecessary. Ecology has destroyed this myth convenient for humans. Now it is clear why it is dangerous, as modern man does, to reduce the diversity of nature.

One- and even two-species communities are very unstable. Instability means that large fluctuations in population density can occur. This circumstance determines the evolution of the ecosystem to a mature state. At the mature stage, feedback regulation increases, which is aimed at maintaining the stability of the system.

High productivity gives low reliability - this is another formulation of the basic law of ecology, from which the following rule follows: "optimal efficiency is always less than maximum." Diversity, in accordance with the basic law of ecology, is directly related to sustainability. However, it is not yet known to what extent this relationship is causal.

The direction of the evolution of the community leads to an increase in symbiosis, the preservation of biogenic substances, and an increase in the stability and content of information. The overall strategy "is aimed at achieving as extensive and diverse an organic structure as possible within the boundaries established by the available energy inflow and the prevailing physical conditions of existence (soil, water, climate, etc.)" (Yu. Odum. Fundamentals ... p. 332).

The ecosystem strategy is “the greatest protection”, the human strategy is “maximum production”. Society seeks to obtain the maximum yield from the developed territory and, in order to achieve its goal, creates artificial ecosystems, and also slows down the development of ecosystems in the early stages of succession, where the maximum yield can be harvested. Ecosystems themselves tend to develop in the direction of achieving maximum stability. Natural systems require low efficiency to maintain maximum energy output, rapid growth, and high stability. By reversing the development of ecosystems and thereby bringing them into an unstable state, a person is forced to maintain "order" in the system, and the costs of this may exceed the benefits obtained by transferring the ecosystem into an unstable state. Any increase in the efficiency of an ecosystem by humans leads to an increase in the cost of maintaining it, up to some limit, when further increase in efficiency is unprofitable due to too large an increase in costs. Thus, it is necessary to achieve not the maximum, but the optimal efficiency of ecosystems, so that an increase in their productivity does not lead to a loss of stability and the result is economically justified.

In stable ecosystems, the losses of energy passing through them are great. And ecosystems that lose less energy (systems with fewer trophic levels) are less resilient. What systems should be developed? It is necessary to determine such an optimal variant in which the ecosystem is sufficiently stable and at the same time the energy loss in it is not too large.

As the history of human transformational activity and the science of ecology show, all extreme options, as a rule, are not the best. In relation to pastures, both “overgrazing” (leading, according to scientists, to the death of civilizations) and “undergrazing” of livestock are bad. The latter occurs because, in the absence of direct consumption of living plants, detritus can accumulate faster than it is decomposed by microorganisms, and this slows down the circulation of minerals.

This example lends itself to more general considerations. Human impact on the natural environment is often accompanied by a decrease in diversity in nature. Through this, the maximization of the harvest and the increase in the possibilities of managing this part of nature are achieved. In accordance with the law of necessary diversity formulated in cybernetics, humanity has two options for increasing the ability to manage the natural environment: either reduce the diversity in it, or increase its internal diversity (by developing culture, improving the mental and psychosomatic qualities of the person himself). The second way is, of course, preferable. Diversity in nature is a necessity, not just a seasoning for life. The ease of the first way is deceptive, although it is widely used. The question is to what extent the increase in the ability to manage ecosystems by reducing the diversity in nature compensates for the decrease in the ability of ecosystems to self-regulate. Again, an optimum must be found between the needs of management at the moment and the needs of maintaining diversity in the natural environment.

The problem of optimizing the relationship between man and the natural environment has another important aspect. The practice of nature-transforming human activity confirms the position that there is a close relationship between changes in the natural environment and human. Therefore, the problem of managing the natural environment can be considered in a certain sense as the problem of managing the biological evolution of man through changes in the natural environment. Modern man can influence his biology both genetically (genetic engineering) and ecologically (through changes in the natural environment). The presence of a connection between ecological processes and the processes of human biological evolution requires that the ecological problem is also considered from the point of view of how we want to see the man of the future. This area is very exciting for both scientists and science fiction writers, but not only technical, but also social and moral problems arise here.

Optimization is a scientific and technical term. But is it possible to find a solution to the problems discussed above within the framework of exclusively science and technology? No, science and technology itself should have general cultural and social guidelines, which are concretized by them. In solving optimization problems, science and technology are a kind of tool, and before using it, you need to decide how and for what purposes to use it.

Even seemingly simple cases of calculating the optimal options for using, say, a resource depend on which optimization criterion is used. K. Watt describes an example of optimizing a water basin system, in accordance with which there is a complete exhaustion of resources in the shortest possible time (K. Watt. Ecology and management of natural resources. M., 1971, p. 412). The example shows the importance of the optimization criterion. But the latter depends on priorities, and they are different for different social groups. It is quite understandable that the criteria are especially different when it comes to optimizing the biological evolution of man himself (more or less firmly one rather vague criterion of optimization can be named - the preservation and development of the biosphere and the human race).

In nature, there are, as it were, natural forces of stratification that lead to the complexity of ecosystems and the creation of ever greater diversity. Acting against these forces pushes ecosystems back. Diversity naturally grows, but not any, but integrated. If a species enters an ecosystem, then it can destroy its stability (as a person does now), if it is not integrated into it. There is an interesting analogy here between the development of an ecosystem and the development of an organism and human society.

2.6. Some other laws and principles important for ecology

Among the laws of nature, there are laws of a deterministic type common in science, which strictly regulate the relationship between the components of an ecosystem, but most are laws as tendencies that do not work in all cases. They resemble, in a sense, legal laws, which do not hinder the development of society if they are occasionally violated by a certain number of people, but hinder normal development if the violations become massive. There are also laws-aphorisms that can be attributed to the type of laws as a restriction of diversity:

1. The law of emergence: the whole always has special properties that its parts do not have.

2. The law of necessary diversity: a system cannot consist of absolutely identical elements, but can have a hierarchical organization and integrative levels.

3. The law of irreversibility of evolution: an organism (population, species) cannot return to its previous state, realized in the series of its ancestors.

4. The law of organization complication: the historical development of living organisms leads to the complication of their organization through the differentiation of organs and functions.

5. Biogenetic law (E. Haeckel): the ontogeny of an organism is a brief repetition of the phylogenesis of a given species, i.e., an individual in his development repeats, in short, the historical development of his species.

6. The law of uneven development of parts of the system: systems of the same level of hierarchy do not develop strictly synchronously - while some reach a higher stage of development, others remain in a less developed state. This law is directly related to the law of necessary variety.

7. The law of conservation of life: life can exist only in the process of movement through the living body of the flow of substances, energy, information.

8. The principle of maintaining order (I. Prigogine): in open systems, entropy does not increase, but decreases until a minimum constant value is reached, which is always greater than zero.

9. The Le Chatelier-Brown principle: when an external influence brings the system out of a state of stable equilibrium, this equilibrium shifts in the direction in which the effect of the external influence is weakened. This principle within the biosphere is violated by modern man. “If at the end of the last century there was still an increase in biological productivity and biomass in response to an increase in the concentration of carbon dioxide in the atmosphere, then since the beginning of our century this phenomenon has not been detected. On the contrary, the biota emits carbon dioxide, and its biomass automatically decreases” (N. F. Reimers. Nadezhdy... p. 55).

10. The principle of energy saving (L. Onsager): with the probability of the development of the process in a certain set of directions allowed by the principles of thermodynamics, the one that provides a minimum of energy dissipation is realized.

11. The law of maximizing energy and information: the system that is most conducive to the receipt, production and efficient use of energy and information has the best chance of self-preservation; the maximum intake of a substance does not guarantee the system success in the competitive struggle.

12. Periodic law of geographical zoning of A. A. Grigorieva - N. N. Budyko: with the change of the physical and geographical zones of the Earth, similar landscape zones and some common properties periodically repeat, i.e. in each zone - subarctic, temperate, subtropical, tropical and equatorial - there is a change of zones according to the scheme: forests? steppe? desert.

13. The law of system development at the expense of the environment: any system can develop only through the use of the material, energy and information capabilities of its environment; absolutely isolated self-development is impossible.

14. The principle of refraction of the acting factor in the hierarchy of systems: the factor acting on the system is refracted through the entire hierarchy of its subsystems. Due to the presence of "filters" in the system, this factor is either weakened or enhanced.

15. The rule of attenuation of processes: with an increase in the degree of equilibrium with the environment or internal homeostasis (in the case of isolation of the system), the dynamic processes in the system decay.

16. The law of physical and chemical unity of living matter by V. I. Vernadsky: all living matter of the Earth is physically and chemically one, which does not exclude biogeochemical differences.

17. Thermodynamic rule of van't Hoff - Arrhenius: temperature rise by 10? C leads to a two-threefold acceleration of chemical processes. Hence the danger of an increase in temperature due to the economic activity of modern man.

18. Schrödinger's rule "about nutrition" of the organism with negative entropy: the orderliness of the organism is higher than the environment, and the organism gives more disorder to this environment than it receives. This rule correlates with Prigogine's principle of maintaining order.

19. Rule of acceleration of evolution: with the growth of the complexity of the organization of biosystems, the duration of the existence of a species on average decreases, and the rate of evolution increases. The average lifespan of a bird species is 2 million years, and that of a mammal species is 800 thousand years. The number of extinct species of birds and mammals in comparison with their total number is large.

20. The principle of genetic pre-adaptation: the ability to adapt in organisms is inherent and due to the practical inexhaustibility of the genetic code. Variants necessary for adaptation are always found in genetic diversity.

21. The rule of the origin of new species from non-specialized ancestors: new large groups of organisms do not originate from specialized representatives of ancestors, but from their relatively non-specialized groups.

22. Darwin's principle of divergence: the phylogeny of any group is accompanied by its division into a number of phylogenetic trunks, which diverge in different adaptive directions from the average initial state.

23. The principle of progressive specialization: a group embarking on the path of specialization, as a rule, in its further development will go along the path of ever deeper specialization.

24. The rule of higher chances of extinction of deeply specialized forms (O. Marsh): more specialized forms die out faster, the genetic reserves of which for further adaptation are reduced.

25. The law of increasing the size (height) and weight (mass) of organisms in the phylogenetic branch. "AT. I. Vernadsky formulated this law in this way: “As the geological time progresses, the surviving forms increase their size (and, consequently, their weight) and then die out.” This happens because the smaller the individuals, the more difficult it is for them to resist the processes of entropy (leading to a uniform distribution of energy), to regularly organize energy flows for the implementation of vital functions. Evolutionarily, the size of individuals therefore increases (although it is a very persistent morphophysiological phenomenon in a short time interval) ”(N.F. Reimers. Nadezhdy ... p. 69).

26. Ch. Darwin's axiom of adaptability: each species is adapted to a strictly defined, specific set of conditions of existence for it.

27. Ecological rule of S. S. Schwartz: each change in the conditions of existence directly or indirectly causes corresponding changes in the ways of implementing the energy balance of the body.

28. The law of relative independence of adaptation: high adaptability to one of the environmental factors does not give the same degree of adaptation to other living conditions (on the contrary, it can limit these possibilities due to the physiological and morphological characteristics of organisms).

29. The law of unity "organism - environment": life develops as a result of a constant exchange of matter and information based on the flow of energy in the total unity of the environment and the organisms inhabiting it.

30. The rule of compliance of environmental conditions with the genetic predestination of the organism: a species can exist as long as and insofar as its environment corresponds to the genetic possibilities of adapting this species to its fluctuations and changes.

31. The law of maximum biogenic energy (entropy) by V. I. Vernadsky - E. S. Bauer: any biological or bio-inert system, being in dynamic equilibrium with the environment and developing evolutionarily, increases its impact on the environment, if this is not prevented by external factors .

32. The law of pressure of the environment of life, or limited growth (C. Darwin): there are restrictions that prevent the offspring of one pair of individuals, multiplying exponentially, from flooding the entire globe.

33. The principle of minimum population size: there is a minimum population size below which its population cannot fall.

34. The rule of representation of a genus by one species: in homogeneous conditions and in a limited area, a taxonomic genus, as a rule, is represented by only one species. Apparently, this is due to the proximity of the ecological niches of species of the same genus.

35. A. Wallace's rule: as you move from north to south, species diversity increases. The reason is that the northern biocenoses are historically younger and are in conditions of less energy from the Sun.

36. The law of depletion of living matter in its island concentrations (G. F. Khilmi): “an individual system operating in an environment with a level of organization lower than the level of the system itself is doomed: gradually losing structure, the system will dissolve in the environment after some time "(G.F. Khilmi. Fundamentals of Biosphere Physics. L., 1966, p. 272). This leads to an important conclusion for human environmental activities: the artificial preservation of small ecosystems (in a limited area, such as a nature reserve) leads to their gradual destruction and does not ensure the conservation of species and communities.

37. The law of the pyramid of energies (R. Lindemann): from one trophic level of the ecological pyramid passes to another, higher level, on average, about 10% of the energy received at the previous level. The reverse flow from higher to lower levels is much weaker - no more than 0.5–0.25%, and therefore it is not necessary to talk about the energy cycle in the biocenosis.

38. The rule of biological amplification: when moving to a higher level of the ecological pyramid, the accumulation of a number of substances, including toxic and radioactive ones, increases in approximately the same proportion.

39. The rule of ecological duplication: an extinct or destroyed species within one level of the ecological pyramid replaces another, similar according to the scheme: a small one replaces a large one, a lower organized one - a more highly organized one, more genetically labile and mutable - less genetically variable. Individuals are crushed, but the total amount of biomass increases, since elephants will never give the same biomass and production per unit area that locusts and even smaller invertebrates can give.

40. The rule of biocenotic reliability: the reliability of a biocenosis depends on its energy efficiency in given environmental conditions and the possibility of structural and functional restructuring in response to changes in external influences.

41. The rule of obligatory filling of ecological niches: an empty ecological niche is always and necessarily naturally filled (“nature does not tolerate emptiness”).

42. The rule of ecotone, or edge effect: at the junctions of biocenoses, the number of species and individuals in them increases, as the number of ecological niches increases due to the emergence of new systemic properties at the junctions.

43. The rule of mutual adaptation of organisms in the biocenosis of K. Möbius - G. F. Morozov: species in the biocenosis are adapted to each other so that their community is an internally contradictory, but a single and interconnected whole.

44. The principle of ecosystem formation: long-term existence of organisms is possible only within the framework of ecological systems, where their components and elements complement each other and are mutually adapted.

45. The law of successional deceleration: processes occurring in mature equilibrium ecosystems that are in a stable state, as a rule, tend to slow down.

46. ​​The rule of maximum energy to maintain a mature system: succession is in the direction of a fundamental shift in the flow of energy in the direction of increasing its amount, aimed at maintaining the system.

47. The law of historical self-development of biosystems (E. Bauer): the development of biological systems is the result of an increase in their external work - the impact of these systems on the environment.

48. The rule of constancy of the number of species in the biosphere: the number of emerging species is on average equal to the number of extinct ones, and the total species diversity in the biosphere is a constant. This rule is true for the formed biosphere.

49. The rule of plurality of ecosystems: the plurality of competitively interacting ecosystems is indispensable for maintaining the reliability of the biosphere.

From these environmental laws, conclusions follow that are fair for the system "man - natural environment". They refer to the type of law as a restriction of diversity, that is, they impose restrictions on the nature-transforming activity of man.

1. The rule of historical growth of production due to the successional rejuvenation of ecosystems. This rule, in essence, follows from the basic law of ecology and now ceases to work, since man thus took everything he could from nature.

2. Law of the boomerang: everything that is extracted from the biosphere by human labor must be returned to it.

3. The law of the indispensability of the biosphere: the biosphere cannot be replaced by an artificial environment, just as, say, new types of life cannot be created. A person cannot build a perpetual motion machine, while the biosphere is practically a "perpetual" motion machine.

4. The law of diminishing natural fertility: "due to the constant withdrawal of crops, and therefore organic matter and chemical elements from the soil, violation of the natural processes of soil formation, as well as long-term monoculture as a result of the accumulation of toxic substances released by plants (soil self-poisoning), on cultivated lands there is a decrease in the natural fertility of soils ... to date, about half of the arable land in the world has lost fertility to varying degrees, and the same amount of land has completely disappeared from intensive agricultural circulation as it is now cultivated (in the 80s, about 7 million hectares were lost per year )” (N.F. Reimers. Hopes... pp. 160–161). The second interpretation of the law of diminishing natural fertility is given in chapter 1: each successive addition of any factor beneficial to the body gives a smaller effect than the result obtained from the previous dose of the same factor.

5. The law of shagreen skin: the global initial natural resource potential is continuously depleted in the course of historical development. This follows from the fact that there are currently no fundamentally new resources that could appear. “For the life of each person, 200 tons of solid substances are needed per year, which he, with the help of 800 tons of water and an average of 1000 W of energy, turns into a product useful for himself” (Ibid., p. 163). All this man takes from what is already in nature.

6. The principle of incompleteness of information: “information when carrying out actions to transform and, in general, any change in nature is always insufficient for an a priori judgment about all the possible results of such actions, especially in the long term, when all natural chain reactions develop” (Ibid., p. 168) .

7. The principle of deceptive well-being: the first success in achieving the goal for which the project was conceived creates an atmosphere of complacency and makes you forget about possible negative consequences that no one expects.

8. The principle of remoteness of the event: descendants will come up with something to prevent possible negative consequences.

The question of how much the laws of ecology can be transferred to the relationship of man with the environment remains open, since man differs from all other species. For example, in most species, the rate of population growth decreases with increasing population density; in humans, on the contrary, population growth in this case accelerates. Therefore, some of the regulatory mechanisms of nature are absent in humans, and this may serve as an additional reason for technological optimism in some, and for environmental pessimists, testify to the danger of such a catastrophe, which is impossible for any other species.

3.1. "The Law of the Minimum" by J. Liebig

limiting Liebig's Law of the Minimum.

Limits of tolerance. Along with the conclusion that "plant growth depends on the nutrient element that is present in the minimum amount", which became the basis of Liebig's "law of the minimum", J. Liebig pointed to the range limiting indicators. It was found that not only a lack, but also an excess of factors such as light, heat and water can be a limiting factor. The concept of the limiting influence of the ecological maximum, along with the minimum, was introduced by W. Shelford (1913), who formulated the “law of tolerance”. The range between two values, the ecological minimum and the ecological maximum, which is characterized in one way or another by all living organisms was called limit of tolerance(from lat. toleratia - patience, tolerance). If a certain organism has a small range of tolerance to one of the variable factors, then this factor deserves close attention, because it may be limiting. For example, oxygen, which is quite available for organisms living in the terrestrial parts of ecosystems, can rarely be limiting. Whereas for organisms living under water, oxygen can become an important limiting factor. In the case of an extreme narrowing of the tolerance range, a living organism can spend all its metabolic energy on overcoming the stress associated with a decrease in the limits of the limiting factor, and die due to a lack of energy for normal life activity. If a polar bear, due to some circumstances, is moved to warmer climes, then it will have to spend all its metabolic energy on overcoming heat stress, and the animal will not have enough energy to get food and preserve its species in nature.

The concept of limiting factors in general extends widely to both biological and physical factors, and to present all that is known on this subject would require a large amount of printed work, which is beyond the scope of this book. However, given that the environmental engineer has to deal with physical factors more often, we will briefly list the main physical and climatic factors.

"The Law of the Minimum" by J. Liebig

Each individual, population, community is simultaneously affected by various factors, but only some of them are vital. These vital factors are called limiting. Most often, at least one factor lies outside the optimum. And the possibility of the existence of a species in a given place depends on this factor. Back in 1840, J. Liebig established that the endurance of an organism is determined by the weakest link in the chain of its environmental needs. It is his priority to study the various factors in plant growth and to find that plant yields can be most effectively increased by improving the minimum factor (usually by increasing the amount of N and P), rather than those nutrients that are required in large quantities, such as, such as carbon dioxide or water. Substances that are required in the smallest quantities, but which are very few in the soil, such as zinc, these substances become limiting. Liebig's concept that "the growth of a plant depends on that nutrient element present in the smallest amount" became known as Liebig's Law of the Minimum.

For successful application in practice of Liebig's concept, two auxiliary principles must be added to it: the first is restrictive ("Liebig's law is strictly applicable only in a stationary state, i.e. when the inflow and outflow of energy and matter are balanced"); the second is the principle of interaction of factors, which states that "a high concentration or availability of one substance or the action of another (not minimal) factor can change the rate of consumption of a nutrient contained in a minimum amount."

For an environmental engineer, the concept of limiting factors is valuable in that it provides a starting point in the study of complex situations in the "man - technology - nature" system. The relationships between the elements of such a system can be quite complex. In the process of solving problems of new equipment and technology, a specialist can highlight probable weaknesses and focus, at least at the beginning, on those characteristics of the environment that may turn out to be critical or limiting.

Liebig's law of the minimum in ecology (with examples)

In this article, we will briefly understand what Liebig's law of the minimum is, one of the fundamental laws in ecology. Another name for this law is the law of the limiting (limiting) factor. Also at the end of the article are some illustrative examples illustrating the law of the minimum.

Liebig's law of the minimum. A bit of history

The law of the minimum was formulated by the German chemist Justus von Liebig. in 1840.

The scientist was mainly engaged in the study of the conditions for the survival of plants in agriculture. He tried to understand at what point it is necessary to apply certain chemical additions to improve the survival of plants.

As a result of his research, von Liebig formulated a law that later turned out to be true not only for agriculture, but for all ecological systems and living organisms.

The law of the limiting (limiting) factor.

The essence of Liebig's law of the minimum

There are different formulations of this law. But the essence of the law of the minimum (or the law of the limiting factor) can be formulated as follows:

• The life of an organism depends on many factors. But, the most significant at any given time is the factor that is most vulnerable.

• In other words, if any of the factors in the body significantly deviates from the norm, then this factor is the most significant, the most critical for the survival of the organism at a given moment in time.

It is important to understand that for the same organism at different times, such critically important (or otherwise limiting) factors can be completely different factors.

The same reasoning applies to entire ecosystems. At this point in time, for example, lack of food can become a limiting factor. At another point in time - the amount of food will be normal, but the limiting factor will be the ambient temperature (too high or too low).

Summarizing the above, we can formulate the law as follows.

Liebig's law of the minimum is:

For the survival of an organism (or eco-system), the most significant is the environmental factor,

which is the most removed (deviates) from its optimal value.

Liebig barrel

Before moving on to examples, it is worth considering the drawing of the so-called Liebig barrel.

In this half-broken barrel - board height is the limiting factor. Obviously, the water will overflow over the smallest plank in the barrel. In this case, the height of the remaining boards will no longer be important to us - it will still be impossible to fill the barrel.

The smallest board is the very factor that deviated the most from the normal value.

According to Liebig's law of the minimum, the repair of the barrel must be started from this board.

Liebig's law of the minimum. Examples

There is a proverb: “Where it is thin, there it breaks” - by and large, it conveys the main essence of Liebig's law. But, let's give a few examples from completely different areas.

An example from agriculture

There are soils where there is not enough phosphorus - so you need to feed fertilizers with phosphorus. But, at other times, fertilizers with calcium are needed. And so on

An example from the wild

In winter, the limiting factor for a hare is food. In summer - you need to escape from the wolf, although there is plenty of food.

Sports example of the law of the minimum

In football: if the left back of the team is the weakest, then through his left flank the team is most likely to concede a goal.

Thus, Liebig's law of the minimum is a universal ecological and life law.

Additional Information:

• Commoner's Laws of Ecology - Read about Commoner's four basic laws of ecology.

Where to hand over for recycling waste, equipment and other things in your city

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1. The law of the minimum Yu. Liebig.

In 1840, the German chemist Justus Liebig, while growing plants on synthetic media, discovered that a certain number and quantity of chemical elements and compounds is necessary for the normal growth of a plant. Some of them should be in the environment in very large quantities, others in small quantities, and still others in general in the form of traces. And, what is especially important: some elements cannot be replaced by others. A medium containing all elements in abundance, except for one, ensures the growth of the plant only until the moment when the amount of the latter is exhausted. Growth is thus limited by the shortage of a single element, the quantity of which was below the required minimum. This law, formulated by J. Liebig in relation to the role of chemical edaphic factors in plant life and called by him the law of the minimum, has, as it turned out later, a universal ecological character and plays an important role in ecology.

The Law of the Minimum: If all environmental conditions turn out to be favorable for the organism in question, with the exception of one that is insufficiently manifested (the value of which approaches the ecological minimum), then in this case this last condition, called the limiting factor, becomes decisive for the life or death of the organism in question, and therefore, its presence or absence in a given ecosystem”.

2. Shelford's law of tolerance.

In 1913, the American ecologist W. Shelford generalized Liebig's law of the minimum, discovering that, in addition to the lower limit of intensity, there is also an upper limit of the intensity of environmental factors, which determines the upper limit of the intensity range corresponding to the conditions of normal life of organisms. In this formulation, the law, called the ecological law of tolerance, began to have a more general universal character.

The law of tolerance (lat. tolerance- patience): "Each organism is characterized by an ecological minimum and an ecological maximum of the intensity of each environmental factor, within which life activity is possible."

The range of the environmental factor between the minimum and maximum is called the tolerance range or area.

Despite the wide variety of environmental factors, a number of general patterns can be identified in the nature of their impact and in the responses of living organisms.

The quantitative range of the factor that is most favorable for life is called ecological optimum (lat. optimus -

The values ​​of the factor lying in the zone of oppression are called ecological pessimism (lat. pessimum- worst).

The minimum and maximum values ​​of the factor at which death occurs are called respectively ecological minimum and ecological maximum .

Graphically, this is illustrated in fig.3-1. The curve in Figure 3-1 is generally not symmetrical.

For example, according to such a factor as temperature, the ecological maximum corresponds to the temperatures at which enzymes and proteins are destroyed (+50 ¸ +60 °С). However, individual organisms can exist at higher temperatures. So, in the hot springs of Komchatka and America, algae were found at t > +80 °C. The lower temperature limit at which life is possible is about -70 °C, although shrubs in Yakutia do not freeze even at this temperature. In suspended animation (gr. anabiosis- survival), i.e. in an inactive state, some organisms persist at absolute zero (-273 °C).

Rice. 3-1. Dependence of vital activity on intensity

We can formulate a number of provisions that complement the law of tolerance:

1. Organisms can have a wide range of tolerance for one environmental factor and a narrow range for another.

2. Organisms with a wide range of tolerance for most factors are usually the most widely distributed.

3. If the conditions for one ecological factor are not optimal for a given species, then the range of tolerance for other ecological factors may also narrow. For example, when the nitrogen content in the soil is close to the minimum, the drought resistance of cereals decreases.

4. During the breeding season, the range of tolerance tends to narrow.

Organisms with a narrow range of tolerance, or highly adapted species that can exist only with small deviations of the factor from the optimal value, are called stenobiont, or stenoeks (gr. stenos- narrow, cramped).

Organisms with a wide range of tolerance, or widely adapted species that can withstand a large amplitude of fluctuations in the environmental factor, are called eurybiont, or euryek (gr. euros- wide).

The property of organisms to adapt to existence in a particular range of environmental factors is called ecological plasticity .

Close to ecological plasticity is the concept ecological valency , which is defined as the ability of an organism to populate a variety of environments.

Thus, stenobionts are ecologically non-plastic; not hardy, have a low ecological valency; eurybionts, on the contrary, are ecologically plastic; more hardy, and have a high ecological valency.

To indicate the relationship of organisms to a particular factor, prefixes are added to its name: wall- and evry-. So, with respect to temperature, there are stenothermal (dwarf birch, banana tree) and eurythermal (temperate plants) species; in relation to salinity - stenohaline (carp, flounder) and euryhaline (stickleback); in relation to the world stenophonic (spruce) and euryfont (rose hip), etc.

Steno- and eurybiontness is manifested, as a rule, in relation to one or a few factors. Eurybionts are usually widespread. Many protozoan eurybionts (bacteria, fungi, algae) are cosmopolitans. Stenobionts, on the contrary, have a limited distribution area. Ecological plasticity and ecological valency of organisms often change during the transition from one stage of development to another; juveniles, as a rule, are more vulnerable and more demanding on environmental conditions than adults.

At the same time, organisms are not slaves to the physical conditions of the environment; they adapt themselves and change the environmental conditions in such a way as to weaken the influence of the limiting factor. Such compensation of limiting factors is especially effective at the community level, but it is also possible at the population level.

Species with a wide geographical distribution almost always form populations adapted to local conditions, called ecotypes . Their optima and tolerance limits correspond to local conditions. The appearance of ecotypes is sometimes accompanied by the genetic fixation of acquired properties and traits, i.e. to the emergence of races.

Organisms living for a long time in relatively stable conditions lose their ecological plasticity, and those that were subject to significant fluctuations of the factor become more tolerant to it, i.e. increase ecological plasticity. In animals, compensation of limiting factors is possible due to adaptive behavior - they avoid extreme values ​​of limiting factors.

When approaching extreme conditions, the energy price of adaptation increases. If superheated water is dumped into a river, then fish and other organisms spend almost all their energy to overcome this stress. They do not have enough energy to obtain food, protection from predators, reproduction, which leads to extinction.

So, organisms in nature depend on:

Liebig's law of the minimum

A living organism in natural conditions is simultaneously exposed to the influence of not one, but many environmental factors. Moreover, any factor is required by the body in certain quantities / doses. Liebig established that the development of a plant or its condition does not depend on those chemical elements that are present in the soil in sufficient quantities, but on those that are not enough. If a

of any, at least one of the nutrients in the soil is less than required by these plants, then it will develop abnormally, slowly, or have pathological deviations.

J. LIBICH's law of minimum- the concept according to which the existence and endurance of an organism is determined by the weakest link in the chain of its ecological needs.
According to the law of the minimum, the vital possibilities of organisms are limited by those environmental factors, the quantity and quality of which are close to the necessary organism or ecosystem.

Liebig's law:

The substance present in the minimum controls the yield, determines its size and stability over time. At the beginning of the 20th century, an American scientist Shelford showed that a thing or any other factor, which is present not only in a minimum, but also in excess compared to the level required by the body, can lead to undesirable consequences for the body. Example: if you place a plant/animal in an experimental chamber and measure the air temperature in it, then the state of the organism will change.

At the same time, some best, optimal level of this factor for the organism is revealed, at which the activity (physiological state) will be maximum. If different factors deviate from the optimal up/down, then the activity will decrease. Upon reaching a certain max/min value, the factor will become incompatible with life processes, changes will occur in the body, leading to death. Similar results can be obtained in experiments with changes in humidity, the content of various salts in water, acidity, the concentration of various substances, etc.

The wider the amplitude of the fluctuation of the factor at which the organism can reduce viability, the higher its stability ( tolerance) to one factor or another. From all of the above it follows:

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Liebig's law

Definition 1

The rules of the minimum are one of the principles that determine the role of the environmental factor in the distribution and number of organisms.

The relative effect of some environmental factors is the stronger, the more its deficit is felt in comparison with others. Formulated by G.O. Liebig (1840) the law as applied to agricultural crops - any living organisms need not just organic and mineral substances, humidity, temperature or any other factors, but their regime.

The reactions of organisms depend on the number of factors. In addition, living organisms under natural conditions are exposed to various environmental factors (both biotic and abiotic) simultaneously. The plant needs a significant amount of nutrients and moisture (potassium, nitrogen, phosphorus) and at the same time in relatively "insignificant" amounts of such an element as molybdenum (boron).

Any species of animals or plants have a distinct selectivity for the composition of food: each plant needs a certain mineral element. All kinds of animals are demanding in their own way to the quality of food. In order to favorably exist and develop normally, organisms must have the entire set of necessary factors in the optimal mode and in sufficient quantity.

The fact that limiting the doses (or absence) of any of the substances necessary for plants, which belong to both micro and macro elements, leads to the same results of growth retardation, was discovered and studied by the German chemist, the founder of agricultural chemistry, Eustace von Liebig. The rules formulated by him are called Liebig's law of the minimum: the size of crops is determined by the number in the soils of those nutrients, the needs of plants in which are satisfied the least. To do this, Liebig depicted a leaky barrel, showing that the lower hole sets the amount of liquid in it.

Remark 1

The law of the minimum is true both for animals and for plants, and also covers a person who, under certain conditions, has to use vitamins or mineral water to compensate for the lack of any element in the body.

Clarifications and changes made to Liebig's law

Subsequently, a number of refinements were made to Liebig's law. A significant amendment and addition is the law of selective action of factors on different functions of the body: any environmental factors affect the functions of organisms in different ways, the optimum for one process, such as respiration, will not be the optimum for another, such as digestion, and vice versa. This group of refinements of Liebig's law includes a rule of phase reactions "harm benefit" that is slightly different from others: a small concentration of a toxicant affects organisms in the direction of increasing its functions, while a higher concentration depresses or even leads to death of the organism. These toxicological patterns are valid for a large number (for example, the healing property of small concentrations of snake venom is famous), but not for all toxic substances.

Remark 2

Liebig's law is the rule of the minimum, is one of the principles that determines the role of environmental factors in the development and distribution of organisms. Formulated by G.O. Liebig (1840) for crops.

According to Liebig's law, "A substance that is at a minimum is controlled by the crop and the size and stability of the latter in time are established." This meant the limiting effect of vital substances present in the soil in small and intermittent quantities. later this generalization began to be interpreted more broadly, taking into account other environmental factors (for example, temperature, time, etc.).