The topic of human impact on ecology and ecology on life on the planet is very relevant today. More and more people are talking about negative impact human activities on nature, global warming, the threat of extinction of some animal species, pollution of the world's oceans, etc. We, being those who are far from indifferent to all this, cannot help but devote one of our articles to the environmental topic.

Below we will talk about how environmental factors can affect living organisms, which will help each of us draw certain conclusions.

Instead of introducing

Despite the fact that the variety of environmental factors is simply enormous, and the nature of their origin can often differ, there are patterns and rules for the influence of these environmental factors on living organisms that are universal.

Whatever the environmental factor, it will affect living organisms as follows:

• Changes are occurring in the geographic distribution of species
• Changes in species fertility and mortality occur
• Migration of species occurs
• Species develop adaptive qualities and adaptations

However, a factor will be most effective if its value is optimal for the body, and not critical. The impact of the factor will affect absolutely all living organisms, including humans.

Patterns of the impact of environmental factors on organisms

• Optimum rule
• Liebig's law of the minimum
• Shelford's Law of Tolerance

Optimum rule

First of all, it should be said that the result of the action of an environmental factor depends on how intense it is. The most favorable range of exposure is called the optimum zone, which guarantees normal life activity. And if the effect of a factor deviates from the optimum zone, then there is a negative impact on the life activity of the species population, i.e. the factor moves into the zone of oppression.

The minimum and maximum values ​​of the factor are called critical points, beyond which the organism can no longer exist. The range of influence of an environmental factor between critical points is the body’s zone of tolerance in relation to a specific factor.

If, for example, we display the effect of a factor graphically, then the point on the X axis that will correspond the best indicator vital activity of the organism, will be the optimal value of the factor or simply the optimum point. However, it is very difficult to determine it, so the optimum zone or is often taken into account.

It follows from this that the points corresponding to the minimum, maximum and optimal indicators are cardinal points that determine possible options the body's response to a specific factor. And if the environment is characterized by conditions where a factor or several factors go beyond the optimum zone and have a depressing effect on the body, then it will be an extreme environment.

The presented patterns are the optimal rule.

Liebig's law of the minimum

To maintain the vital functions of living organisms, environmental conditions must be combined in a certain way. For example, when the environment has all favorable conditions Except for one thing, this one condition plays a decisive role in the life of a particular organism. Considering that it limits the development of the organism, it should be called a limiting factor. In other words, the limiting factor is an environmental factor with a value that goes beyond the survival of the species.

Initially, scientists stopped that the development of living organisms is limited by the lack of one element (light, moisture, mineral salts, etc.). However, in the middle of the 19th century, the German organic chemist Eustace Liebig was the first to experimentally prove that plant growth depends on the nutritional component initially present in minimum quantity. This phenomenon called Liebig's law of minimum.

If we give this law modern formulation, then it will look like this: the endurance of a living organism determines the weakest link in its chain environmental needs.

Shelford's Law of Tolerance

70 years after the discovery of Liebig's law of the minimum, it was established that the limiting effect is not only a deficiency, but also an excess of a factor (heavy rains destroy the crop, the soil becomes infertile from an oversaturation of fertilizers, etc.).

This idea was introduced by the American zoologist Victor Shelford, who formulated the law of tolerance. This law sounds like this: the role of a limiting factor in the prosperity of an organism can be performed by both a minimum and a maximum environmental impact, and the range between them indicates the limit of tolerance (the amount of endurance) or the ecological valence of the organism to a specific environmental factor.

The very principle of limiting factors is applicable to any type of living organisms: animals and plants, biotic and abiotic forms. For example, competition of one species with another is a limiting factor; weeds, pests or insufficient populations of another species are also limiting factors. However, based on the law of tolerance, if some substance or energy is present in the environment in excess, pollution of the environment begins.

As for the limit of endurance of the organism, it can be measured at the stage of transition from one stage of development to another, because Often young individuals are more demanding of the environment and vulnerable than adults. The most critical period from the point of view of the influence of any factors can be called the breeding period, when many factors acquire the status of limiting.

It should also be noted that everything said before regarding the endurance of the body concerned only one factor, but living nature is characterized by all environmental factors.

Interaction of environmental factors

The shift in the most optimal zone and tolerance limits of a living organism in relation to some environmental factor depends on the combination of the actions of other factors. This phenomenon is called constellation or interaction of environmental factors.

For example, everyone knows that hot weather is much easier to bear when the air is dry rather than humid; You can freeze faster at low temperatures when the wind blows; plants growing in the shade need less zinc than plants growing in the sun, etc. To put it somewhat differently, there is compensation for the effects of environmental factors.

But this compensation is limited, because one factor is not able to 100% replace another. If there is no water or one of the nutrients, the plants will die, even if other factors are in perfect combination. And from this we can conclude that every environmental condition that supports life is of equal importance, and any factor can limit the existence of a living organism. This law is called the law of equivalence of living conditions.

Among the huge number of laws that determine the interaction of an individual or a person with the environment, one can also highlight the rule of compliance of environmental conditions with the genetic predetermination of the organism. According to this rule, the existence of a species is determined by the correspondence of the natural environment to its genetic potential for adaptation to changes and fluctuations.

Afterword

Any type of living organism appeared in a specific environment, adapted to it to some extent, and the continuation of its life is possible only in it or as close to it as possible. Rapid and drastic changes in the environment may cause the body to simply not be able to adapt to it, because its genetic adaptive potential will be insufficient for this.

And this is one of the main hypotheses explaining the extinction of large reptiles due to a sharp change environmental conditions on the planet, because it is much more difficult for large organisms to adapt than for small ones, and adaptation requires a huge amount of time. Based on this, serious changes environment pose a threat to any living creature on the planet, including humans.

Take care of nature and try to maintain cleanliness not only inside yourself, but also outside!

Children begin to receive elementary school, and in means mass media environmental issues are not of concern last place, ecology is still a young, complex and mysterious science. Its scientific base is not that great, and its complex models are confusing. Nevertheless, knowledge and understanding of the basic laws in this area is the basis of the worldview modern man. This article will consider one of the main laws of ecology - the law of the minimum, formulated long before the formation of science itself.

To the history of discovery

The law of the minimum was formulated in 1840 by the outstanding chemist, professor of Hesse Eustace von Liebig. This scientist and outstanding teacher He is also known for the invention of the Liebig refrigerator, which is still used today in chemical laboratories for the fractional separation of chemical compounds. His book “Chemistry as applied to agriculture” actually gave rise to the science of agricultural chemistry, and to him the title of baron and two Orders of St. Anne. Liebig studied plant survival and the role of chemical additives in increasing it. This is how he formulated the law of the minimum or limiting factor, which turned out to be true for all biological systems. And not only for biological ones, which we will demonstrate with examples.

A little theory

Comfort zone

Most often, environmental factors are tolerated by organisms within certain limits, which are limited by threshold values ​​beyond which the organism’s vital activity is inhibited. These are critical points of existence. Between them there are zones of tolerance (tolerance) and a zone of optimum (comfort) - the range of the beneficial influence of the factor. The minimum and maximum points of the impact of an environmental factor determine the possibilities of the body's response to a specific factor. Going beyond the optimum zone can lead to the following:

• removal of a species from a particular range (for example, population range shift or species migration);
• changes in fertility and mortality (for example, when sudden changes environmental conditions);
• to adaptation (fitness) and the emergence of new species with new phenotypic and genetic characteristics.

The essence of the law of the minimum

The life of a biological system, be it an organism or a population, depends on the action of many factors of a biotic and abiotic nature. The formulation of the law of the minimum may vary, but the essence remains constant: when any factor deviates significantly from the norm, then it becomes the most significant for the system and the most critical for life. At the same time, different indicators can act as limiting factors for the body at different periods of time.

Options are possible

All living organisms live and adapt to a complex of environmental factors. And the impact of the factors of this complex is always unequal. The factor can be leading (very important) or secondary. Different factors will be leading for different organisms, and at different periods of the life of one organism, certain environmental factors may be the main factors for it. In addition, the same factors may be limiting for some organisms and not limiting for others. For example, sunlight for plants is a necessary element for the processes of photosynthesis. But for fungi, soil saprotrophs or deep-sea animals it is not at all necessary. Or the presence of oxygen in the water will be, but its presence in the soil will not.

Conditions of use

The law of the minimum is limited in its application by two auxiliary principles:

1. The law is applicable without further clarification only to equilibrium systems, namely only under conditions steady state systems when the exchange of energy and substances of the system with the environment is regulated by their leakage.
2. The second principle of applying the law of the minimum is related to compensatory capabilities organisms and systems. Under certain conditions, the limiting factor can be replaced by a non-limiting factor, but present in sufficient or high content. This will lead to a change in the need for the substance that is available in minimal quantities.

Visual illustration

The effect of this law is clearly demonstrated by the barrel named after the scientist. In this broken barrel, the limiting factor is the height of the boards. In accordance with the ecological law of the minimum, repairing it must begin with the smallest board. It is she who is the factor that is most removed from normal values, optimal for the survival of the organism. Without eliminating the impact of this factor, there is no point in filling the barrel - other factors do not have such a significant effect on at the moment time.

Where it's thin, that's where it breaks

It is this proverb that conveys the essence of the law of the minimum in ecology and more. For example, in agriculture content indicators are taken into account minerals in soils. If the soil contains only 20% phosphorus of the norm, calcium - 50%, and potassium -95%, then fertilizers that contain phosphorus must be applied first. IN wildlife for deer in summer the limiting factor will be the amount of food, and in winter - altitude snow cover. Or for a pine tree that grows in a shady forest, the limiting factor will be light, on dry sandy soil - water, and in swampy areas - temperature in summer.

Another example not related to ecology. If the right defender in the team is the weakest, then it is from his flank that the enemy will most likely break through. This is true in sports, in art, in business. A significant mistake businessmen often make is underestimating the harm that a weak employee causes, even in secondary positions. It is not without reason that they say that the quality of a company is determined by the quality of its worst employees. And the strength of a chain always depends on its weakest link.

In 1840, the German chemist Justus Liebig, growing plants in synthetic media, discovered that a certain number and amount of chemical elements and connections. Some of them must be present in the environment in very large quantities, others in small quantities, and others generally in the form of traces. And, what is especially important: some elements cannot be replaced by others. An environment containing all elements in abundance, except one, ensures the growth of the plant only until 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 the life of plants 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.

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 minimum, discovering that in addition to the lower limit of intensity, there is also an upper limit to the intensity of factors external environment, which defines 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.

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

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 most favorable for life is called ecological optimum (lat. optimus -

the best).

The factor values ​​lying in the inhibition zone are called environmental pessimum (lat. pessimum- the worst).

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

This is illustrated graphically in Fig.3-1. The curve in Figure 3-1 is usually not symmetrical.

For example, for such a factor as temperature, the ecological maximum corresponds to the temperatures at which enzymes and proteins are destroyed (+50 ¸ +60 ° C). However, individual organisms can exist even with more high temperatures. Thus, 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 survive at absolute zero (-273 °C).

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

environmental factor.

A number of provisions can be formulated 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 widespread.

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

Organisms with a narrow range of tolerance, or narrowly adapted species, capable of existing only with small deviations of the factor from the optimal value, are called stenobionts, or stenoecs (gr. stenos- narrow, cramped).

Organisms with a wide range of tolerance, or widely adapted species that can withstand large amplitudes of environmental factor fluctuations, are called eurybionts, or euryecs (gr. eurys- 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 valence , which is defined as the ability of an organism to inhabit a variety of environments.

Thus, stenobionts are ecologically nonplastic, i.e. are not hardy, have low ecological valence; On the contrary, eurybionts are ecologically plastic, i.e. are more hardy and have a high ecological valence.

To indicate the relationship of organisms to a specific factor, prefixes are added to its name: steno- And evry-. So, in relation to temperature there are stenothermic (dwarf birch, banana tree) and eurythermic (temperate plants) species; in relation to salinity - stenohaline (crucian carp, flounder) and euryhaline (stickleback); in relation to light - stenophonic (spruce) and euryphonous (rose hips), etc.

Steno- and eurybiontism manifests itself, as a rule, in relation to one or a few factors. Eurybionts are usually widespread. Many simple eurybionts (bacteria, fungi, algae) are cosmopolitan. Stenobionts, on the contrary, have a limited distribution area. Ecological plasticity and ecological valence of organisms often changes during the transition from one stage of development to another; young individuals, as a rule, are more vulnerable and more demanding of environmental conditions than adults.

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

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

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

When approaching extreme conditions, it increases energy price adaptation. If superheated water is released into a river, fish and other organisms spend almost all their energy coping with this stress. They lack energy to obtain food, protect themselves from predators, and reproduce, which leads to extinction.

So, organisms in nature depend on:

Limiting factors. Liebig's "Law of the Minimum"

It is clear that the needs different types different in each specific environment. However, along with this, there are a minimum of factors that are necessary for the existence of a living organism. In the so-called stationary state (the state of the system is more or less stable and is not transitional), the limiting substance will be the substance whose amount is closest to the necessary minimum. For the first time, the issue of the minimum amount of necessary substance was dealt with by J. Liebig, who in 1840, long before the appearance of the term “ecology,” based on the study of the mineral nutrition of plants, investigated the dependence of their growth on certain chemical elements or substances. Based on his research, J. Liebig derived the so-called law of the minimum: plant growth depends not so much on the presence of all substances, but on the minimum amount of a substance, the absence of which, in turn, leads to growth retardation. Compensating for the lack of one element with another does not work. The substance, which is found in minimal quantities, regulates the yield and determines its size and stability over time.

Over time, certain additions were made to this law, but they did not change the essence of the law itself (temperature, time, etc.), but significantly complicated the application of the established pattern. In addition, since the establishment of this pattern by J. Liebig, scientists have noted that it requires clarification when applied in practice. To apply the law of the minimum, Yu. Odum suggests using auxiliary principles, which, in his opinion, should be two.

The first auxiliary principle is the limiting principle: Liebig's law can be applied without clarification only to stationary state conditions, when the influx of energy and substances is regulated by leakage, that is, the system is in a state of equilibrium.

Yu. Odum draws attention to the fact that the system is characterized by dynamics, and therefore the introduction of a limiting principle will limit the errors that arise during long-term studies of ecosystems.

The second supporting principle concerns the interaction of factors. It has been noted that, under certain conditions, high concentrations or sufficient a certain substance, or the action of a second, limiting factor may change the need for a minimum amount of a substance.

An example could be the replacement of calcium use by shellfish with strontium, or the following pattern: plants that grow in the sun have less need for zinc, so zinc ceases to be a limiting element. Second auxiliary

principle, introduced by Yu. Odum, indicates the inappropriateness of analyzing the state of the system based on small quantity elements. He insists on the need for comprehensive analysis in any environmental study.

Interaction of environmental factors. Shelford's Law of Tolerance

As Liebig's research has shown, the development of a living organism is determined not only by the deficiency of one or another factor, but also by their excess. So, each organism has its own limits, which fluctuate between a minimum and a maximum, that is, an optimum that ensures the existence of the organism. Each species has its own limits. The concept of the limiting role of maximum and minimum and the need for optimal conditions for the existence of a species was introduced by V. Shelford (1913). His principle is better known as the law of tolerance;

The natural limiting factor in the existence of an organism can be either a minimum or maximum environmental impact, the range between which determines the degree of endurance (tolerance) of the organism to this factor.

Yu. Odum (1975) introduces a number of additions to Shelford’s law regarding the heterogeneity of the impact of environmental factors and the response of living organisms to them:

Organisms have a wider range of tolerance to each factor, and a narrow range to another;

Organisms with a large range of tolerance tend to be widespread;

If the conditions of existence determined by one environmental factor change beyond the optimum, then the range of tolerance to other environmental factors also changes;

In nature, organisms often find themselves in conditions that are far from optimally established in laboratory experiments;

The period of reproduction and growth, as a rule, is critical; the limits of the body’s tolerance at this time are much narrower than those of an adult.

The explanations provided by Yu. Odum greatly help in clarifying the reasons for the heterogeneity of the results obtained when conducting environmental studies. Consequently, in any environmental study, there is a need for a thorough analysis of not only the physicochemical conditions of the environment or the degree of influence of living organisms on each other, but also the phases of the organism’s existence. The influence of optimal conditions on the growth, reproduction and existence of certain organisms can be clearly demonstrated by the rate of development and fruiting of crops depending on temperature parameters. Those that grow in optimal conditions will grow faster and ripen earlier than those that grow in conditions close to critical.

Rice. 2.3. Plant growth in relation to temperature (Nazaruk, Senchina, 2000)

To characterize the amplitude of tolerance of species in ecology, a number of terms are used. To the name of the ecofactor, which characterizes the effect on a living organism, two words are added: sten (gr. Stenos) - narrow and evry (gr. Euros - wide) stenothermic - eurythermal in relation to temperature

Stenohydric - euryhydric - // - waters

Stenophagnia - euryphagnium - // - food

Stenohaline - Euryhaline - // - salinity

Stenooykny - evrioykny - // - places of residence

Example: the development of eggs of different fish occurs when different temperatures. If salmon eggs develop at temperatures from 0 to 14 ° C with an optimum of 4 ° C, then in relation to frog eggs they will be stenothermic, since the temperature limits for the development of frog eggs are from 0 ° C to 30 ° C with an optimum of 22 ° C.

The interaction of key environmental factors may depend on changes that occur in the system, that is, on the interaction of abiotic and biotic factors. Changes in solar radiation (light, as is known, belongs to the main climatic factors) leads to changes in the illumination of the earth's surface, which, in turn, can lead to changes in photoperiodism in the life of animals and plants. Changes in illumination can lead to changes in the temperature and humidity of a given system. An increase in humidity together with solar radiation can change the temperature regime. A striking example interaction of factors may be a forest, where layering and changes in certain biotic and abiotic factors well expressed. Transcarpathia, in particular the mountainous part of the region, is characterized by overgrazing of livestock, and, as a result, there is a rapid disruption of the functioning of forest areas, where branches and leaves are gnawed to a certain height, and there is no regrowth. Often a person acts as the main biotic element of an ecosystem and, thanks to its activity, appears new type systems. A good example in this regard is the high-mountain meadows of the Carpathians. For a long time believed that high mountain meadows (mountain Runa, Krasnaya, Tyapish and others) are natural formations. The fallacy of this opinion is indicated by the experiment of Professor S.S. Fodor. They noticed that the totality of eco-factors individual areas highlands are not typical for subalpine meadows. To verify the correctness of this assumption, he founded an experiment in the Runa Valley (1,428 m above sea level) to restore the upper border of the forest. Artificial plantings have been monitored for 35 years coniferous trees. All trees planted in this place, feel great, that is, a complex of ecofactors provides them with optimal conditions existence. Conclusion: the vast majority of Carpathian valleys are artificial, created by man. Each species or species group chooses conditions that provide it with optimal existence, that is, it is distributed along a gradient of conditions.

The basis environmental characteristics organisms are based on their reaction to the influence of environmental factors. An organism can survive only within a range of variability this factor, which is also called amplitude. Both very high (maximum) and very low (small) values ​​of environmental factors can be detrimental to the body. The critical value of a given factor, expressed in numbers, above or below which the organism cannot exist, is called the critical point. Between these critical values ​​the zone of environmental tolerance is located (Fig. 2.4).

Within the zone of environmental tolerance, the intensity of environmental factors is different. Along with the critical points, there are pessimal zones in which the body’s activity is significantly limited by the action external conditions. Next are the comfort zones, in which there is a clear increase in environmental protection.

shares of the body. In the center there is an optimum zone, which is favorable for the functioning of the body.

A scheme of relationships in the range of environmental tolerance was proposed in 1924 by the German ecologist and zoogeographer R. Hesse, who called it the valence of environmental factors. It is worth noting that the curve that represents environmental valency within the tolerance zone does not always have a symmetrical appearance with the optimal zone located in the center. For example, for freshwater organisms the optimum is at the lower limit of the salt content in the water, while for marine organisms it is at the opposite end of the factor variability in the tolerance zone, where the salt content is high.

1. General provisions. The environment is everything that surrounds the organism, i.e. this is that part of nature with which the organism is in direct or indirect interactions.

Under environment We understand the complex of environmental conditions that affect the life of organisms. The complex of conditions consists of various elements - environmental factors. Not all of them affect organisms with the same force. Thus, a strong wind in winter is unfavorable for large, open-living animals, but it does not affect smaller ones that hide under the snow or in burrows, or live in the ground. Those factors that have any effect on organisms and cause adaptive reactions in them are called environmental factors .

The influence of environmental factors affects all life processes of organisms and, above all, their metabolism. Adaptations of organisms to their environment are called adaptations. The ability to adapt is one of the main properties of life in general, since it provides the very possibility of its existence, the ability of organisms to survive and reproduce.

2. Classification of environmental factors. Environmental factors have different natures and specific actions. By their nature they are divided into two large groups: abiotic and biotic. If we divide factors according to the reasons for their occurrence, then they can be divided into natural (natural) and anthropogenic. Anthropogenic factors can also be abiotic and biotic.

Abiotic factors(or physicochemical factors) - temperature, light, pH, salinity, radioactive radiation, pressure, air humidity, wind, currents. These are all properties inanimate nature that directly or indirectly affect living organisms.

Biotic factors - these are forms of influence of living beings on each other. The surrounding organic world is an integral part of the environment of every living creature. Mutual connections organisms are the basis for the existence of populations and biocenoses.

Anthropogenic factors- these are forms of human action that lead to changes in nature as the habitat of other species or directly affect their lives.

The action of environmental factors can lead to:

– to the elimination of species from biotopes (change of biotope, territory, shift in population range; example: bird migration);

– changes in fertility (population density, reproductive peaks) and mortality (death with rapid and sharp changes in environmental conditions);

– to phenotypic variability and adaptation: modification variability - adaptive modifications, winter and summer hibernation, photoperiodic reactions, etc.

3. Limiting factors .Shelford's and Liebig's laws

Body reaction the effect of a factor is determined by the dosage of this factor. Very often, environmental factors, especially abiotic ones, are tolerated by the body only within certain limits. The effect of a factor is most effective at a certain optimal value for a given organism. The range of action of the environmental factor is limited to the corresponding extreme threshold values(minimum and maximum points) of a given factor at which the existence of an organism is possible. The maximum and minimum tolerable values ​​of the factor are the critical points beyond which death occurs. The endurance limits between critical points are called environmental valency or tolerance living beings in relation to a specific environmental factor. The population density distribution obeys normal distribution. The population density is higher, the higher closer value factor to the average value, which is called the ecological optimum of the species for this parameter. This law of distribution of population density, and therefore vital activity, is called common law biological resistance.

The range of beneficial effects of a factor on organisms of a given species is called optimum zone(or comfort zone). The points of optimum, minimum and maximum constitute three cardinal points that determine the possibility of the body's reaction to a given factor. The greater the deviation from the optimum, the more pronounced the inhibitory effect of this factor on the body. This range of factor values ​​is called pessimum zone(or zone of oppression). The considered patterns of the influence of a factor on the body are known as optimum rule .

Other patterns have been established that characterize the interaction of the organism and the environment. One of them was established by the German chemist J. Liebig in 1840 and was named Liebig's law of minimum, according to which plant growth is limited by the lack of a single biogenic element, the concentration of which is at a minimum. If other elements are contained in sufficient quantity, and the concentration of this single element drops below normal, the plant will die. Such elements are called limiting factors. So, the existence and endurance of an organism are determined by the weakest link in the complex of its environmental needs. Or the relative effect of a factor on the body is greater, the more this factor approaches the minimum compared to others. The size of the harvest is determined by the presence in the soil of that nutrient element, the need for which is least satisfied, i.e. This element is in minimal quantity. As its content increases, the yield will increase until another element is at a minimum.

Later, the law of the minimum began to be interpreted more broadly, and currently they talk about limiting environmental factors. An environmental factor plays a limiting role in the case when it is absent or is lower critical level, or exceeds the maximum tolerable limit. In other words, this factor determines the ability of the organism to attempt to invade a particular environment. The same factors can be either limiting or not. An example with light: for most plants it is a necessary factor as a supplier of energy for photosynthesis, while for fungi or deep-sea and soil animals this factor is not necessary. Phosphates in sea ​​water– limiting factor in plankton development. Oxygen in soil is not a limiting factor, but in water it is a limiting factor.

A corollary from Liebig's law: a deficiency or excessive abundance of any limiting factor can be compensated by another factor that changes the body's attitude towards the limiting factor.

However, not only those factors that are at a minimum are of limiting importance. For the first time, the idea of ​​a limiting influence maximum value factor on a par with the minimum was expressed in 1913 by the American zoologist V. Shelford. According to the formulated Shelford's law of tolerance the existence of a species is determined by both a deficiency and an excess of any of the factors having a level close to the limit of tolerance by a given organism. In this regard, all factors whose level approaches the limit of the body’s endurance are called limiting .

4. Frequency of environmental factors. The action of a factor can be: 1) regularly periodic, changing the strength of the impact in connection with the time of day, season of the year or the rhythm of ebb and flow in the ocean; 2) irregular, without a clear periodicity, for example, catastrophic phenomena - storms, showers, tornadoes, etc.; 3) directed over certain periods of time, for example, global cooling, or overgrowing of water bodies.

Organisms always adapt to the whole complex of conditions, and not to any one factor. But in complex action environment value individual factors unequal. Factors can be leading (main) and secondary. The leading factors differ for different organisms, even if they live in the same place. They also differ for one organism at different periods of its life. Thus, for early spring plants the leading factor is light, and after flowering - moisture and abundance. nutrients.

Primary periodic factors (daily, lunar, seasonal, annual) – adaptation of organisms takes place, rooted in the hereditary basis (gene pool), since this periodicity existed before the appearance of life on Earth. Climatic zonation, temperature, ebb and flow, illumination. It is with the primary periodic factors that the climatic zones, which determine the distribution of species on Earth.

Secondary periodic factors. Factors resulting from changes in primary factors (temperature - humidity, temperature - salinity, temperature - time of day).

5. Abiotic factors. Universal groups: climatic, edaphic, factors of the aquatic environment. In nature there is a general interaction of factors. Principle feedback: release of toxic substances destroyed the forest - change in microclimate - change in ecosystem.

1)Climatic factors. Depends on the main factors: latitude and position of the continents. Climatic zoning led to the formation of biogeographical zones and belts (tundra zone, steppe zone, taiga zone, deciduous forest zone, desert and savannah zone, sub tropical forests, tropical forest zone). The ocean is divided into Arctic-Antarctic, boreal, subtropical and tropical-equatorial zones. There are many secondary factors. For example, monsoon climate zones that form a unique animal and flora. Latitude has the greatest effect on temperature. The position of the continents is the reason for the dryness or humidity of the climate. The internal regions are drier than the peripheral ones, which greatly influences the differentiation of animals and plants on the continents. The wind regime (an integral part of the climate factor) plays an extremely important role important role in the formation life forms plants.

The most important climatic factors: temperature, humidity, light.

Temperature. Everything living is in the temperature range - from 00 to 500C. These are lethal temperatures. Exceptions. Space cold. Eurythermic1 and stenothermic organisms. Cold-loving stenothermic and heat-loving stenothermic. The abyssal environment (0˚) is the most constant environment. Biogeographical zonation (arctic, boreal, subtropical and tropical). Poikilothermic organisms are cold-water organisms with variable temperatures. The body temperature approaches the ambient temperature. Homeothermic - warm-blooded organisms with a relatively constant internal temperature. These organisms have great advantages in using the environment.

Humidity. Water in the soil and water in the air are factors that have great importance in life organic world.

Hydrobionts (aquatic) - live only in water. Hydrophiles (hydrophytes) – very humid environments (frogs, earthworms). Xerophiles (xerophytes) are inhabitants of arid climates.

Light. Determines the existence of autotrophic organisms (chlorophyll synthesis), which constitute the most important level in trophic chains. But there are plants without chlorophyll (fungi, bacteria - saprophytes, some orchids).

2)Edaphic factors. All physical and chemical properties soil Mainly affects soil inhabitants.

3)Aquatic environmental factors. Temperature, pressure, chemical composition (oxygen, salinity). According to the degree of salt concentration in aquatic environment organisms are: freshwater, saltwater, marine euryhaline and stenohaline (i.e. living in conditions of a wide and narrow range of salinity, respectively). By temperature factor organisms are divided into cold-water and warm-water, as well as a group of cosmopolitans. Based on their lifestyle in the aquatic environment (depth, pressure), organisms are divided into planktonic, benthic, deep-sea and shallow-sea.

6. Biotic factors. These are factors that control the relationships of organisms in populations or communities. There are two main types of such relationships:

– intraspecific – population and interpopulation (demographic, ethological);

7. Anthropogenic factors. Although man influences wildlife Through changes in abiotic factors and biotic relationships of species, human activity on the planet is highlighted as a special force. Main ways anthropogenic influence are: importation of plants and animals, reduction of habitats and destruction of species, direct impact on vegetation cover, plowing of land, cutting and burning of forests, grazing of domestic animals, mowing, drainage, irrigation and watering, air pollution, creation of ruderal habitats (garbage dumps, wastelands) and dumps, the creation of cultural phytocenoses. To this should be added the diverse forms of crop and livestock farming activities, measures to protect plants, protect rare and exotic species, hunting animals, their acclimatization, etc. Influence anthropogenic factor Since the appearance of man on Earth, it has constantly intensified. Currently, the fate of the living surface of our planet and all types of organisms is in the hands of human society, depends on anthropogenic influence on nature.

2.Noise pollution of the environment. Noise protection.

Noise (acoustic) pollution (English Noise pollution, German Lärm) - annoying noise anthropogenic origin, disrupting the life of living organisms and humans. Annoying noises exist in nature (abiotic and biotic), but it is incorrect to consider them pollution, since living organisms have adapted to them in progress evolution .

Main source noise pollution are vehicles- cars, railway trains and airplanes.

In cities, noise pollution in residential areas can be greatly increased by poor urban planning (e.g. airport within the city limits).

In addition to transport (60÷80% of noise pollution), other important sources of noise pollution in cities are industrial enterprises, construction and renovation work, car alarm, dog barking, noisy people etc.

With the advent of the post-industrial era, more and more sources of noise pollution (as well as electromagnetic) also appears inside a person’s home. The source of this noise is household and office equipment.

More than half the population Western Europe lives in areas where the noise level is 55÷70 dB.

Noise protection

Like all other types anthropogenic impacts, the problem of environmental noise pollution is international in nature. The World Health Organization, taking into account the global nature of environmental noise pollution, has developed a long-term program to reduce noise in cities and populated areas peace.
In Russia, protection from noise exposure is regulated by Law Russian Federation“On Environmental Protection” (2002) (Article 55), as well as government regulations on measures to reduce noise in industrial enterprises, in cities and other populated areas.
Noise protection - very complex problem and to solve it, a set of measures is needed: legislative, technical and technological, urban planning, architectural and planning, organizational, etc. To protect the population from harmful influence noise intensity, duration of action and other parameters are regulated by regulatory legislative acts. Gosstandart established uniform sanitary and hygienic standards and rules for limiting noise in enterprises, cities and other populated areas. The standards are based on such levels of noise exposure, the effect of which over a long period of time does not cause adverse changes in the human body, namely: 40 dB during the day and 30 at night. Permissible levels of transport noise are set within 84-92 dB and will decrease over time.
Technical and technological measures come down to noise protection, which is understood as comprehensive technical measures to reduce noise in production (installation of sound-insulating casings of machines, sound absorption, etc.), in transport (emission mufflers, replacement of shoe brakes with disc brakes, noise-absorbing asphalt, etc.). ).
At the urban planning level, protection from noise exposure can be achieved by the following measures (Shvetsov, 1994):
- zoning with removal of noise sources outside the building;
- organizing a transport network that excludes the passage of noisy highways through residential areas;
- removal of noise sources and device protective zones around and along sources of noise impact and the organization of green spaces;
- laying highways in tunnels, constructing noise-protective embankments and other noise-absorbing obstacles along the paths of noise propagation (screens, excavations, forging holes);
Architectural and planning measures provide for the creation of noise-protective buildings, i.e., buildings that provide the premises with normal acoustic conditions using structural, engineering and other measures (sealing windows, double doors with a vestibule, cladding walls with sound-absorbing materials, etc.).
A certain contribution to protecting the environment from noise impacts is made by the prohibition of sound signals from vehicles, flights over the city, restriction (or prohibition) of aircraft takeoffs and landings at night, and other organizations.
these measures.

However, these measures are unlikely to give the desired environmental effect if the main thing is not understood: protection from noise exposure is not only a technical problem, but also an asocial one. It is necessary to educate sound culture(Bon-Edarenko, 1985) and consciously avoid actions that would contribute to an increase in noise pollution of the environment.

Law of limiting factors

In the total pressure of the environment, factors are identified that most strongly limit the success of the life of organisms. Such factors are called limiting or limiting. In its simplest form, the fundamental law of the minimum, formulated by J. Liebig in 1840, concerns the successful growth and productivity of crops that depend on a substance that is at a minimum compared to other necessary agrochemicals. Later (in 1909), the law of the minimum was interpreted by F. Blackman more broadly, as the action of any ecological factor that is at a minimum: environmental factors that have the worst significance in specific conditions especially limit the possibility of the existence of a species in these conditions in spite of and in spite of optimal combination of other hotel conditions.

In addition to the minimum, V. Shelford’s law also takes into account the maximum environmental factor: the limiting factor can be both the minimum and the maximum environmental impact.

The value of the concept of limiting factors is that it provides a starting point for research difficult situations. It is possible to identify probable weak links in the environment that may turn out to be critical or limiting. Identifying limiting factors is the key to controlling the life activity of organisms. For example, in agroecosystems on highly acidic soils, wheat yield can be increased by applying various agronomic interventions, but the best effect is obtained only as a result of liming, which will remove the limiting effect of acidity. For successful application The Law of Limiting Factors In practice, two principles must be observed. The first is restrictive, that is, the law is strictly applicable only under stationary conditions, when the inflow and outflow of energy and substances are balanced. The second takes into account the interaction of factors and the adaptability of organisms. For example, some plants need less zinc if they are not growing in bright sunlight. sunlight, but in the shade.

Ecological significance individual factors for various groups and species of organisms are extremely diverse and require competent accounting.

2. Noise pollution. Basic parameters

The world of sounds is an integral part of the habitat of humans, many animals, and is not indifferent to some plants. The rustling of leaves, the splash of waves, the sound of rain, the singing of birds - all this is familiar to humans. Meanwhile, various and multi-scale processes of technogenesis have significantly changed and are changing the natural acoustic field of the biosphere, which is manifested in noise pollution of the natural environment, which has become a serious factor of negative impact. According to prevailing ideas, noise pollution is one of the forms of physical (wave) pollution of the environment, to which adaptation of organisms is not possible. It is caused by an excess of the natural noise level and an abnormal change sound characteristics(periodicity, sound intensity). Depending on the strength and duration of the noise, it can cause significant harm to health. Long-term exposure to noise leads to hearing damage. The noise is measured in bels (B).

Noise as a pollution factor in residential areas is perceived by people quite individually. Differentiation of perception of noise impacts varies by age, as well as depending on temperament and general condition health. The human hearing organ can adapt to some constant or repeated noise, but in all cases this does not protect against the occurrence and development of any pathology. Noise irritation is one of the causes of sleep disturbance. The consequences of this chronic fatigue, nervous exhaustion, reduction in life expectancy, which, according to scientific research, can be 8-12 years. The sound intensity scale is shown in Figure 2.1. Noise stress affects everyone higher organisms. Noise exceeding 80-90 dB affects the release of pituitary hormones, which control the production of other hormones. For example, the release of cortisone from the adrenal cortex may increase. Cortisone weakens the liver's fight against substances harmful to the body. Under the influence of such noise, restructuring occurs energy metabolism in muscle tissue. Excessive noise can cause peptic ulcers.

According to the World Health Organization, reactions to noise from outside nervous system begins at 40 dB, and at 70 dB and more, significant violations are possible. There are also functional disorders in the body, manifested in changes in the activity of the brain and central nervous system, and increased blood pressure. An acceptable level of noise is considered to be such that it does not disturb sound comfort, does not cause unpleasant sensations, and with prolonged exposure there are no changes in a set of physiological indicators. Noise standards are brought into compliance with the Sanitary Standards for Permissible Noise.

In general, the problem of reducing noise pollution is quite complex, and its solution should be based on integrated approach. One of the expedient, environmentally sound ways to combat noise is to maximize the landscaping of the area. Plants have an exceptional ability to retain and absorb a significant portion of sound energy. A dense hedge can reduce the noise produced by cars by 10 times. It has been proven that green partitions made of maple (up to 15.5 dB), poplar (up to 11 dB), linden (up to 9 dB) and spruce (up to 5 dB) have the highest sound insulating ability. When regulating physical influences Environmental literacy and culture of the population are essential. Often the person himself makes the situation worse by directing it at himself or taking external influences related to everyday life or entertainment activities.