Competitors, etc. - are characterized by significant variability in time and space. The degree of variability of each of these factors depends on the characteristics of the habitat. For example, temperatures vary greatly at the land surface but are nearly constant at the ocean floor or deep in caves.

The same environmental factor has different meaning in the life of co-living organisms. For example, the salt regime of the soil plays a primary role in the mineral nutrition of plants, but is indifferent to most terrestrial animals. The intensity of illumination and the spectral composition of light are extremely important in the life of phototrophic plants, and in the life of heterotrophic organisms (fungi and aquatic animals), light does not have a noticeable effect on their life activity.

Environmental factors act on organisms differently. They can act as irritants that cause adaptive changes in physiological functions; as limiters that make it impossible for certain organisms to exist under given conditions; as modifiers that determine morphological and anatomical changes in organisms.

Classification of environmental factors

It is customary to highlight biotic, anthropogenic And abiotic environmental factors.

• Biotic factors- all the many environmental factors associated with the activities of living organisms. These include phytogenic (plants), zoogenic (animals), microbiogenic (microorganisms) factors.
• Anthropogenic factors- all the many factors associated with human activity. These include physical (the use of nuclear energy, travel on trains and planes, the influence of noise and vibration, etc.), chemical (the use of mineral fertilizers and pesticides, pollution of the Earth’s shells with industrial and transport waste; biological (food; organisms for which humans may be a habitat or a source of nutrition), social (related to people’s relationships and life in society) factors.
• Abiotic factors- all the many factors associated with processes in inanimate nature. These include climatic (temperature, humidity, pressure), edaphogenic (mechanical composition, air permeability, soil density), orographic (relief, altitude above sea level), chemical (gas composition of air, salt composition of water, concentration, acidity), physical (noise, magnetic fields, thermal conductivity, radioactivity, cosmic radiation)

Frequently encountered classification of environmental factors (environmental factors)

BY TIME: evolutionary, historical, active

BY PERIODICITY: periodic, non-periodic

ORDER OF APPEARANCE: primary, secondary

BY ORIGIN: cosmic, abiotic (also known as abiogenic), biogenic, biological, biotic, natural-anthropogenic, anthropogenic (including man-made, environmental pollution), anthropic (including disturbances)

BY WEDNESDAY OF APPEARANCE: atmospheric, aquatic (aka humidity), geo-morphological, edaphic, physiological, genetic, population, biocenotic, ecosystem, biosphere

THE NATURE: material-energy, physical (geophysical, thermal), biogenic (also biotic), informational, chemical (salinity, acidity), complex (ecological, evolutionary, system-forming, geographical, climatic)

BY OBJECT: individual, group (social, ethological, socio-economic, socio-psychological, species (including human, social life)

ACCORDING TO ENVIRONMENTAL CONDITIONS: density dependent, density independent

BY DEGREE OF IMPACT: lethal, extreme, limiting, disturbing, mutagenic, teratogenic; carcinogenic

BY IMPACT SPECTRUM: selective, general action

Wikimedia Foundation. 2010.

See what “Environmental factor” is in other dictionaries:

environmental factor- — EN ecological factor An environmental factor that, under some definite conditions, can exert appreciable influence on organisms or their communities, causing the increase or… …

environmental factor- 3.3 environmental factor: Any indivisible element of the environment that can have a direct or indirect impact on a living organism at least during one of its stages individual development. Notes 1. Environmental... ...

environmental factor- ekologinis veiksnys statusas T sritis augalininkystė apibrėžtis Bet kuris aplinkos veiksnys, veikiantis augalą ar jų bendriją ir sukeliantis prisitaikomumo reakcijas. atitikmenys: engl. ecological factor rus. environmental factor... Žemės ūkio augalų selekcijos ir sėklininkystės terminų žodynas

LIMITING FACTOR- (LIMITING) any environmental factor, the quantitative and qualitative indicators of which somehow limit the life activity of the organism. Ecological Dictionary, 2001 Factor limiting (limiting) any environmental factor,... ... Ecological dictionary

Ecological- 23. Environmental passport of a thermal power plant: title= Environmental passport of a thermal power plant. Basic provisions of LDNTP. L., 1990. Source: P 89 2001: Recommendations for diagnostic monitoring of filtration and hydrochemical... ... Dictionary-reference book of terms of normative and technical documentation

ECOLOGICAL FACTOR- any property or component of the environment that affects the body. Ecological Dictionary, 2001 Ecological factor is any property or component of the environment that affects the organism ... Ecological dictionary

environmental hazard factor- A natural process caused by the evolution of the earth and leading directly or indirectly to a decrease in the quality of environmental components below established standards. [RD 01.120.00 KTN 228 06] Topics: main oil pipeline transport ... Technical Translator's Guide

WORRY FACTOR- an anthropogenic factor that has a harmful effect on the life of wild animals. disturbance factors may include various noises, direct human intrusion into natural systems; especially noticeable during the breeding period... Ecological dictionary

SUBSTANCE-ENERGY FACTOR- any factor whose influence is adequate to the transferred flow of matter and energy. Wed. Information factor. Ecological encyclopedic dictionary. Chisinau: Main editorial office of the Moldavian Soviet Encyclopedia. I.I. Dedu. 1989 ... Ecological dictionary

ATMOSPHERIC FACTOR- a factor related to the physical condition and chemical composition ohm of the atmosphere (temperature, degree of rarefaction, presence of pollutants). Ecological encyclopedic dictionary. Chisinau: Main editorial office of the Moldavian Soviet Encyclopedia. I.I.... ... Ecological dictionary

Books

• Lobbying activities of corporations in modern Russia, Andrey Bashkov. The influence of the environmental factor on the implementation of modern political processes, both in Russia and in the world Lately is increasingly intensifying. In the current political realities...
• Aspects of environmental responsibility of economic entities of the Russian Federation, A. P. Garnov, O. V. Krasnobaeva. Today, the environmental factor is acquiring transboundary significance, clearly correlating with the largest geosociopolitical processes in the world. One of the main sources of negative…

ENVIRONMENTAL FACTORS

Environmental factors - these are certain conditions and elements of the environment that have a specific effect on a living organism. The body reacts to environmental factors with adaptive reactions. Environmental factors determine the living conditions of organisms.

Classification of environmental factors (by origin)

• 1. Abiotic factors are a set of inanimate factors that affect the life and distribution of living organisms. Among them are:
• 1.1. Physical factors- such factors, the source of which is physical state or phenomenon (for example, temperature, pressure, humidity, air movement, etc.).
• 1.2. Chemical factors - factors that are determined by the chemical composition of the environment (salinity of water, oxygen content in the air, etc.).
• 1.3. Edaphic factors(soil) - a set of chemical, physical, mechanical properties of soils and rocks that affect both the organisms for which they are a habitat and the root system of plants (humidity, soil structure, content of nutrients, etc.).
• 2. Biotic factors - a set of influences of the life activity of some organisms on the life activity of others, as well as on the inanimate component of the environment.
• 2.1. Intraspecific interactions characterize the relationships between organisms at the population level. They are based on intraspecific competition.
• 2.2. Interspecies interactions characterize the relationships between different species, which can be favorable, unfavorable and neutral. Accordingly, we denote the nature of the impact +, - or 0. Then the following types of combinations of interspecific relationships are possible:
• 00 neutralism- both types are independent and have no effect on each other; Rarely found in nature (squirrel and elk, butterfly and mosquito);

+0 commensalism- one species benefits, while the other has no benefit, no harm either; (large mammals (dogs, deer) serve as carriers of fruits and seeds of plants (burdock), receiving neither harm nor benefit);

-0 amensalism- one species experiences inhibition of growth and reproduction from another; (light-loving herbs growing under the spruce suffer from shading, but the tree itself does not care about this);

++ symbiosis- mutually beneficial relationships:

• ? mutualism- species cannot exist without each other; figs and the bees that pollinate them; lichen;
• ? protocooperation- coexistence is beneficial to both species, but is not a prerequisite for survival; pollination of various meadow plants by bees;
• - - competition- each type has an adverse effect on the other; (plants compete with each other for light and moisture, i.e. when they use the same resources, especially if they are insufficient);

Predation - a predatory species feeds on its prey;

There is another classification of environmental factors. Most factors change qualitatively and quantitatively over time. For example, climatic factors (temperature, illumination, etc.) change throughout the day, season, and year. Factors whose changes are repeated regularly over time are called periodic . These include not only climatic, but also some hydrographic ones - ebbs and flows, some ocean currents. Factors that arise unexpectedly (volcanic eruption, predator attack, etc.) are called non-periodic .

Environmental factors and the concept of ecological niche

Concept of environmental factor

1.1.1. The concept of environmental factors and their classification

From an environmental perspective Wednesday - these are natural bodies and phenomena with which the organism is in direct or indirect relationships. The environment surrounding an organism is characterized by enormous diversity, consisting of many elements, phenomena, conditions that are dynamic in time and space, which are considered as factors .

Environmental factor - this is any environmental condition, capable of exerting a direct or indirect influence on living organisms, at least during one of the phases of their individual development. In turn, the body reacts to the environmental factor with specific adaptive reactions.

Thus, environmental factors- these are all elements of the natural environment that influence the existence and development of organisms, and to which living beings react with adaptation reactions (beyond the ability of adaptation, death occurs).

It should be noted that in nature, environmental factors act in a complex manner. This is especially important to remember when assessing the impact of chemical pollutants. In this case, the “total” effect, when negative action one substance is superimposed on the negative effect of others, and to this is added the influence of a stressful situation, noise, various physical fields, which significantly changes the MPC values ​​given in reference books. This effect is called synergistic.

The most important concept is limiting factor, that is, one whose level (dose) approaches the limit of the body’s endurance, the concentration of which is lower or higher than optimal. This concept is defined by Liebig's laws of minimum (1840) and Shelford's laws of tolerance (1913). The most often limiting factors are temperature, light, nutrients, currents and pressure in the environment, fires, etc.

The most common organisms are those with a wide range of tolerance to all environmental factors. The highest tolerance is characteristic of bacteria and blue-green algae, which survive in a wide range of temperatures, radiation, salinity, pH, etc.

Ecological studies related to determining the influence of environmental factors on the existence and development of certain types of organisms, the relationship of the organism with the environment, are the subject of science autecology . Branch of ecology that studies population associations various types plants, animals, microorganisms (biocenoses), the ways of their formation and interaction with the environment, is called synecology . Within the boundaries of synecology there are phytocenology, or geobotany (the object of study is groupings of plants), biocenology (groupings of animals).

Thus, the concept of an environmental factor is one of the most general and extremely broad concepts of ecology. Accordingly, the task of classifying environmental factors has proven to be very difficult, so there is still no generally accepted option. At the same time, agreement has been reached regarding the advisability of using certain characteristics when classifying environmental factors.

Traditionally, three groups of environmental factors have been identified:

1) abiotic (inorganic conditions - chemical and physical, such as the composition of air, water, soil, temperature, light, humidity, radiation, pressure, etc.);

2) biotic (forms of interaction between organisms);

3) anthropogenic (forms of human activity).

Today, there are ten groups of environmental factors (the total number is about sixty), combined into a special classification:

1. by time – factors of time (evolutionary, historical, active), periodicity (periodic and non-periodic), primary and secondary;

2. by origin (cosmic, abiotic, biotic, natural, technogenic, anthropogenic);

3. by environment of occurrence (atmospheric, water, geomorphological, ecosystem);

4. by nature (informational, physical, chemical, energy, biogenic, complex, climatic);

5. by object of influence (individual, group, species, social);

6. by degree of influence (lethal, extreme, limiting, disturbing, mutagenic, teratogenic);

7. according to the conditions of action (density-dependent or independent);

8. according to the spectrum of influence (selective or general action).

First of all, environmental factors are divided into external (exogenous or entopic) And internal (endogenous) in relation to a given ecosystem.

TO external These include factors whose actions, to one degree or another, determine the changes occurring in the ecosystem, but they themselves practically do not experience its reverse influence. These are solar radiation, precipitation intensity, atmospheric pressure, wind speed, current speed, etc.

Unlike them internal factors correlate with the properties of the ecosystem itself (or its individual components) and actually form its composition. These are the numbers and biomass of populations, stocks various substances, characteristics of the ground layer of air, water or soil mass, etc.

The second common classification principle is the division of factors into biotic And abiotic . The first includes various variables that characterize the properties of living matter, and the second - the non-living components of the ecosystem and its external environment. The division of factors into endogenous - exogenous and biotic - abiotic does not coincide. In particular, there are both exogenous biotic factors, for example, the intensity of the introduction of seeds of a certain species into the ecosystem from outside, and endogenous abiotic factors, such as the concentration of O 2 or CO 2 in the ground layer of air or water.

The classification of factors according to general character their origin or object of influence. For example, among exogenous factors there are meteorological (climatic), geological, hydrological, migration (biogeographic), anthropogenic factors, and among endogenous factors - micrometeorological (bioclimatic), soil (edaphic), water and biotic.

An important classification indicator is nature of dynamics environmental factors, especially the presence or absence of its frequency (daily, lunar, seasonal, perennial). This is due to the fact that the adaptive reactions of organisms to certain environmental factors are determined by the degree of constancy of the influence of these factors, that is, their frequency.

Biologist A.S. Monchadsky (1958) distinguished primary periodic factors, secondary periodic factors and non-periodic factors.

TO primary periodic factors These include mainly phenomena associated with the rotation of the Earth: the change of seasons, daily changes in illumination, tidal phenomena, etc. These factors, which are characterized by regular periodicity, acted even before the appearance of life on Earth, and emerging living organisms had to immediately adapt to them.

Secondary periodic factors - a consequence of primary periodic ones: for example, humidity, temperature, precipitation, the dynamics of plant food, the content of dissolved gases in water, etc.

TO non-periodic These include factors that do not have the correct periodicity or cyclicity. These are soil factors and various types of natural phenomena. Anthropogenic impacts on the environment are often non-periodic factors that can occur suddenly and irregularly. Since the dynamics of natural periodic factors is one of the driving forces of natural selection and evolution, living organisms, as a rule, do not have time to develop adaptive reactions, for example, to a sharp change in the content of certain impurities in the environment.

A special role among environmental factors belongs to summative (additive) factors characterizing the numbers, biomass or population densities of organisms, as well as reserves or concentrations of various forms of matter and energy, the temporal changes of which are subject to conservation laws. Such factors are called resources . For example, they talk about the resources of heat, moisture, organic and mineral food, etc. In contrast, factors such as the intensity and spectral composition of radiation, noise level, redox potential, wind or current speed, size and shape of food, etc., which greatly affect organisms, are not classified as resources, i.e. .To. conservation laws do not apply to them.

The number of possible environmental factors seems potentially unlimited. However, in terms of the degree of impact on organisms, they are far from equivalent, as a result of which in ecosystems different types some factors stand out as the most significant, or imperative . In terrestrial ecosystems, exogenous factors usually include the intensity of solar radiation, air temperature and humidity, the intensity of precipitation, wind speed, the rate of introduction of spores, seeds and other embryos or the influx of adults from other ecosystems, as well as all kinds of forms anthropogenic impact. Endogenous imperative factors in terrestrial ecosystems are the following:

1) micrometeorological - illumination, temperature and humidity of the ground layer of air, the content of CO 2 and O 2 in it;

2) soil - temperature, humidity, soil aeration, physical and mechanical properties, chemical composition, humus content, availability of mineral nutrients, redox potential;

3) biotic - population density different types, their age and sex composition, morphological, physiological and behavioral characteristics.

1.1.2. The space of environmental factors and the function of the response of organisms to a set of environmental factors

The intensity of the impact of each environmental factor can be characterized numerically, that is, described by a mathematical variable that takes a value on a certain scale.

Environmental factors can be ordered by their strength relative to their impact on an organism, population, ecosystem, that is ranked . If the value of the first most influential factor is measured by the variable X 1, second - variable X 2 , … , n th - variable x n etc., then the entire complex of environmental factors can be represented by the sequence ( X 1 , X 2 , … , x n, ...).In order to characterize the many possible complexes of environmental factors that obtain at different values ​​of each of them, it is advisable to introduce the concept of a space of environmental factors, or, in other words, ecological space.

The space of environmental factors Let's call the Euclidean space, the coordinates of which are compared to the ranked environmental factors:

To quantitatively characterize the impact of environmental factors on the vital signs of individuals, such as growth rate, development, fertility, life expectancy, mortality, nutrition, metabolism, physical activity, etc. (let them be numbered with an index k= 1, …, m), the concept of f at n To ts And I X O T To l And ka . Values ​​accepted by the indicator with number k on a certain scale with varying environmental factors, as a rule, they are limited from below and from above. Let us denote by a segment on the scale of values ​​of one of the indicators ( k th) vital activity of the ecosystem.

Response function k- indicator on the totality of environmental factors ( X 1 , X 2 , … , x n, ...) is called a function φ k, displaying ecological space E to the scale Ik:

,

which to each point ( X 1 , X 2 , … , x n, …) space E matches the number φ k(X 1 , X 2 , … , x n, …) on the scale Ik .

Although the number of environmental factors is potentially unlimited and, therefore, the dimensions of ecological space are infinite E and the number of response function arguments φ k(X 1 , X 2 , … , x n, ...), in reality it is possible to identify a finite number of factors, for example n, with the help of which it is possible to explain a given part of the total variation of the response function. For example, the first 3 factors can explain 80% of the total variation in the indicator φ , the first 5 factors – 95%, the first 10 – 99%, etc. The rest, not included in the list of factors indicated, do not have a decisive impact on the indicator being studied. Their influence can be considered as some " ecological"noise superimposed on the action of imperative factors.

This allows from infinite-dimensional space E go to it n-dimensional subspace En and consider the narrowing of the response function φ k to this subspace:

and where εn+1 – random " environmental noise".

Any living organism does not need temperature, humidity, mineral and organic substances or any other factors in general, but their specific regime, that is, there are some upper and lower limits on the amplitude of permissible fluctuations of these factors. The wider the limits of any factor, the higher the stability, that is tolerance of this organism.

In typical cases, the response function has the form of a convex curve, monotonically increasing from the minimum value of the factor xj s (lower tolerance limit) to a maximum at the optimal factor value xj 0 and monotonically decreasing towards the maximum value of the factor xj e (upper limit of tolerance).

Interval Xj = [x j s, x j e ] is called tolerance interval for this factor, and point xj 0 at which the response function reaches an extremum is called optimum point on this factor.

The same environmental factors have different effects on organisms of different species living together. For some they may be favorable, for others they may not. An important element is the reaction of organisms to the influence of an environmental factor, the negative effect of which can occur in the event of an excess or deficiency of the dose. Therefore, there is the concept of a favorable dose or optimum zones factor and pessimum zones (range of factor dose values ​​in which organisms feel depressed).

The ranges of the optimum and pessimum zones are the criterion for determining ecological valence – the ability of a living organism to adapt to changes in environmental conditions. It is expressed quantitatively by the range of the environment within which the species normally exists. The ecological valency of different species can be very different (reindeer can withstand air temperature fluctuations from -55 to +25÷30°C, and tropical corals die even when the temperature changes by 5-6°C). According to ecological valency, organisms are divided into stenobionts – with low adaptability to environmental changes (orchids, trout, Far Eastern hazel grouse, deep-sea fish) and eurybionts – with greater adaptability to environmental changes (Colorado beetle, mice, rats, wolves, cockroaches, reeds, wheatgrass). Within the boundaries of eurybionts and stenobionts, depending on a specific factor, organisms are divided into eurythermic and stenothermic (based on their response to temperature), euryhaline and stenohaline (based on their response to the salinity of the aquatic environment), euryphotes and stenophotes (based on their response to lighting).

To express the relative degree of tolerance, there are a number of terms in ecology that use the prefixes steno -, which means narrow, and evry - - wide. Species that have a narrow tolerance range (1) are called stenoeks , and species with a wide range of tolerance (2) – euryecami on this factor. Imperative factors have their own terms:

by temperature: stenothermic - eurythermic;

by water: stenohydric – euryhydric;

according to salinity: stenohaline – euryhaline;

according to food: stenophagous – euryphagous;

according to the choice of habitat: stenooic – euryoic.

1.1.3. Law of limiting factor

The presence or prosperity of an organism in a given habitat depends on a complex of environmental factors. For each factor there is a range of tolerance, beyond which the body is not able to exist. The impossibility of flourishing or the absence of an organism is determined by those factors whose values ​​approach or exceed the limits of tolerance.

Limiting We will consider a factor according to which, in order to achieve a given (small) relative change in the response function, a minimum relative change in this factor is required. If

then the limiting factor will be Xl, that is, the limiting factor is along which the gradient of the response function is directed.

It is obvious that the gradient is directed normal to the boundary of the tolerance region. And for the limiting factor, all other things being equal, there is a greater chance of going beyond the area of ​​tolerance. That is, the limiting factor is the factor whose value is closest to the lower limit of the tolerance interval. This concept is known as " law of the minimum "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 demonstrated in 1840. organic chemist Yu. Liebig, one of the founders of agrochemistry, who put forward theory of mineral nutrition of plants. He was the first to study the influence of various factors on plant growth, establishing that crop yield is often limited by nutrients that are not required in large quantities, such as carbon dioxide and water, since these substances are usually present in the environment in abundance, but those that are required in minute quantities, for example, zinc, boron or iron, of which there is very little in the soil. Liebig's conclusion that "plant growth depends on the nutrient element that is present in minimum quantity", became known as Liebig's "law of the minimum".

70 years later, the American scientist V. Shelford showed that not only a substance present in a minimum can determine the yield or viability of an organism, but an excess of some element can lead to undesirable deviations. For example, an excess of mercury in the human body relative to a certain norm causes severe functional disorders. If there is a lack of water in the soil, the assimilation of mineral nutrition elements by the plant is difficult, but an excess of water leads to similar consequences: suffocation of the roots, the occurrence of anaerobic processes, acidification of the soil, etc. are possible. Excess and lack of pH in the soil also reduces the yield in a given location. According to V. Shelford, factors present in both excess and deficiency are called limiting, and the corresponding rule is called the law of “limiting factor” or “ law of tolerance ".

The law of the limiting factor is taken into account in measures to protect the environment from pollution. Exceeding the norm of harmful impurities in air and water poses a serious threat to human health.

A number of auxiliary principles can be formulated that complement the “law of tolerance”:

1. Organisms may 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 widespread.

3. If conditions for one environmental factor are not optimal for a 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 range of one or another environmental factor determined in the laboratory.

5. The breeding season is usually critical; During this period, many environmental factors often become limiting. Tolerance limits for reproducing individuals, seeds, embryos and seedlings are usually narrower than for non-reproducing adult plants or animals.

The actual limits of tolerance in nature are almost always narrower than the potential range of activity. This is due to the fact that the metabolic costs of physiological regulation at extreme values ​​of factors narrow the range of tolerance. As conditions approach extremes, adaptation becomes increasingly costly, and the body becomes increasingly less protected from other factors, such as diseases and predators.

1.1.4. Some basic abiotic factors

Abiotic factors of the terrestrial environment . The abiotic component of the terrestrial environment represents a set of climatic and soil factors, consisting of many dynamic elements that influence both each other and living beings.

The main abiotic factors of the terrestrial environment are as follows:

1) Radiant energy coming from the Sun (radiation). Propagates in space in the form of electromagnetic waves. Serves as the main source of energy for most processes in ecosystems. On the one hand, the direct effect of light on protoplasm is fatal to the organism, on the other hand, light serves as the primary source of energy, without which life is impossible. Therefore, many morphological and behavioral characteristics of organisms are associated with solving this problem. Light is not only a vital factor, but also a limiting one, both at maximum and minimum levels. About 99% of the total energy of solar radiation consists of rays with a wavelength of 0.17÷4.0 microns, including 48% in the visible part of the spectrum with a wavelength of 0.4÷0.76 microns, 45% in the infrared (wavelength from 0.75 microns to 1 mm) and about 7% for ultraviolet (wavelength less than 0.4 microns). Infrared rays are of primary importance for life, and in the processes of photosynthesis, orange-red and ultraviolet rays play the most important role.

2) Illumination of the earth's surface , associated with radiant energy and determined by the duration and intensity of the luminous flux. Due to the rotation of the Earth, light and dark periods periodically alternate. Illumination plays a vital role for all living things, and organisms are physiologically adapted to the cycle of day and night, to the ratio of dark and light periods of the day. Almost all animals have so-called circadian (circadian) rhythms of activity associated with the cycle of day and night. In relation to light, plants are divided into light-loving and shade-tolerant.

3) Surface temperature globe determined temperature conditions atmosphere and is closely related to solar radiation. It depends both on the latitude of the area (the angle of incidence of solar radiation on the surface) and on the temperature of the incoming air masses. Living organisms can exist only within a narrow temperature range - from -200°C to 100°C. As a rule, the upper limit values ​​of the factor turn out to be more critical than the lower ones. The range of temperature fluctuations in water is usually smaller than on land, and the temperature tolerance range of aquatic organisms is usually narrower than that of corresponding terrestrial animals. Thus, temperature is an important and very often limiting factor. Temperature rhythms, together with light, tidal, and humidity rhythms, largely control seasonal and daily activity plants and animals. Temperature often creates zonation and stratification of habitats.

4) Ambient air humidity , associated with its saturation with water vapor. The lower layers of the atmosphere are richest in moisture (up to a height of 1.5÷2 km), where up to 50% of all moisture is concentrated. The amount of water vapor contained in the air depends on the air temperature. The higher the temperature, the more moisture the air contains. For each temperature there is a certain limit of air saturation with water vapor, which is called maximum . The difference between maximum and given saturation is called moisture deficiency (lack of saturation). Humidity deficiency - the most important environmental parameter, since it characterizes two quantities at once: temperature and humidity. It is known that an increase in moisture deficiency during certain periods of the growing season promotes increased fruiting of plants, and in a number of animals, such as insects, leads to reproduction up to the so-called “outbreaks”. Therefore, many methods for predicting various phenomena in the world of living organisms are based on the analysis of the dynamics of moisture deficiency.

5) Precipitation , closely related to air humidity, are the result of condensation of water vapor. Atmospheric precipitation and air humidity are of decisive importance for the formation of the water regime of the ecosystem and, thus, are among the most important imperative environmental factors, since water supply is the most important condition for the life of any organism, from a microscopic bacterium to a giant sequoia. The amount of precipitation depends mainly on the paths and nature of large movements of air masses, or so-called “weather systems”. The distribution of precipitation over the seasons is an extremely important limiting factor for organisms. Precipitation - one of the links in the water cycle on Earth, and in their loss there is a sharp unevenness, and therefore they distinguish humid (wet) and arid (dry) zones. The maximum precipitation is in tropical forests (up to 2000 mm/year), the minimum in deserts (0.18 mm/year). Zones with precipitation less than 250 mm/year are already considered arid. As a rule, an uneven distribution of precipitation over the seasons is found in the tropics and subtropics, where the wet and dry seasons are often well defined. In the tropics, this seasonal rhythm of humidity regulates the seasonal activity of organisms (especially reproduction) in much the same way that the seasonal rhythm of temperature and light regulates the activity of organisms in the temperate zone. In temperate climates, precipitation is usually more evenly distributed throughout the seasons.

6) Gas composition atmosphere . Its composition is relatively constant and includes predominantly nitrogen and oxygen with an admixture of small amounts of CO 2 and argon. Other gases - in trace quantities. In addition, the upper layers of the atmosphere contain ozone. Typically, atmospheric air contains solid and liquid particles of water, oxides of various substances, dust and smoke. Nitrogen – the most important biogenic element involved in the formation of protein structures of organisms; oxygen , mainly coming from green plants, provides oxidative processes; carbon dioxide (CO 2) is a natural damper of solar and reciprocal terrestrial radiation; ozone plays a screening role in relation to the ultraviolet part of the solar spectrum, which is destructive for all living things. Impurities of tiny particles affect the transparency of the atmosphere and prevent the passage of sunlight to the surface of the Earth. The concentrations of oxygen (21% by volume) and CO 2 (0.03% by volume) in the modern atmosphere are to some extent limiting for many higher plants and animals.

7) Movement of air masses (wind) . The cause of wind is a pressure difference caused by unequal heating of the earth's surface. The wind flow is directed towards lower pressure, that is, where the air is warmer. The force of the Earth's rotation affects the circulation of air masses. In the surface layer of air, their movement affects all meteorological elements of the climate: temperature, humidity, evaporation from the Earth’s surface and plant transpiration. Wind – the most important factor in the transfer and distribution of impurities in atmospheric air. Wind performs an important function of transporting matter and living organisms between ecosystems. In addition, wind has a direct mechanical effect on vegetation and soil, damaging or destroying plants and destroying soil cover. Such wind activity is most typical for open flat areas of land, seas, coasts and mountainous regions.

8) Atmospheric pressure . Pressure cannot be called a direct limiting factor, although some animals undoubtedly react to its changes; however, pressure is directly related to weather and climate, which have a direct limiting effect on organisms.

Abiotic factors of soil cover . Soil factors are clearly endogenous in nature, since the soil is not only a “factor” of the environment surrounding organisms, but also a product of their vital activity. The soil – this is the frame, the foundation on which almost any ecosystem is built.

The soil - the final result of the action of climate and organisms, especially plants, on the parent rock. Thus, the soil consists of the original material - the underlying mineral substrate And organic component, in which organisms and their waste products are mixed with finely ground and modified starting material. The spaces between the particles are filled with gases and water. Texture and soil porosity – the most important characteristics that largely determine the availability of nutrients to plants and soil animals. Synthesis and biosynthesis processes take place in the soil; various chemical reactions transformations of substances associated with the life of bacteria.

1.1.5. Biotic factors

Under biotic factors understand the totality of influences of the life activity of some organisms on others.

Relationships between animals, plants, microorganisms (they are also called co-actions ) are extremely diverse. They can be divided into straight And indirect, are mediated through changes in their presence of relevant abiotic factors.

The interactions of living organisms are classified in terms of their reactions to each other. In particular, they highlight homotypic reactions between interacting individuals of the same species and heterotypic reactions during co-actions between individuals of different species.

One of the most important biotic factors is food (trophic) factor . The trophic factor is characterized by the quantity, quality and availability of food. Any type of animal or plant has a clear selectivity to the composition of food. There are different types monophagous feeding on only one species, polyphages , feeding on several species, as well as species feeding on a more or less limited range of food, called broad or narrow oligophages .

Relationships between species are naturally necessary. Species cannot be divided into enemies and them victims, since the relationships between species are reciprocal. Disappearance² victims² may lead to extinction ² enemy².

An environmental factor is any element of the environment that can have a direct or indirect impact on living organisms during at least one of the phases of their individual development.

Any organism in the environment is exposed to a huge number of environmental factors. The most traditional classification of environmental factors is their division into abiotic, biotic and anthropogenic.

Abiotic factors is a set of environmental conditions that affect a living organism (temperature, pressure, background radiation, illumination, humidity, day length, composition of the atmosphere, soil, etc.). These factors can affect the body directly (directly), such as LIGHT and heat, or indirectly, such as the terrain, which determines the action of direct factors (illumination, wind moisture, etc.).

Anthropogenic factors are the totality of the influences of human activity on the environment (emissions of harmful substances, destruction of the soil layer, disturbance of natural landscapes). One of the most important anthropogenic factors is pollution.
- physical: the use of nuclear energy, travel on trains and planes, the influence of noise and vibration
- chemical: the use of mineral fertilizers and pesticides, pollution of the Earth’s shells with industrial and transport waste
- biological: food; organisms for which humans can be a habitat or source of food
- social - related to relationships between people and life in society

Environmental conditions

Environmental conditions, or ecological conditions, are abiotic environmental factors that vary in time and space, to which organisms react differently depending on their strength. Environmental conditions impose certain restrictions on organisms. The amount of light penetrating through the water column limits the life of green plants in water bodies. The abundance of oxygen limits the number of air-breathing animals. Temperature determines the activity and controls the reproduction of many organisms.
The most important factors determining the living conditions of organisms in almost all living environments include temperature, humidity and light.

Photo: Gabriel

Temperature

Any organism is able to live only within a certain temperature range: individuals of the species die at too high or too low temperatures. Somewhere within this interval, temperature conditions are most favorable for the existence of a given organism, its vital functions are carried out most actively. As the temperature approaches the boundaries of the interval, the speed of life processes slows down and, finally, they stop altogether - the organism dies.
The limits of temperature tolerance vary among different organisms. There are species that can tolerate temperature fluctuations over a wide range. For example, lichens and many bacteria are able to live at very different temperatures. Among animals, warm-blooded animals have the greatest range of temperature tolerance. The tiger, for example, tolerates both the Siberian cold and the heat of the tropical regions of India or the Malay Archipelago equally well. But there are also species that can live only within more or less narrow temperature limits. This includes many tropical plants, such as orchids. In the temperate zone, they can only grow in greenhouses and require careful care. Some reef-forming corals can only live in seas where the water temperature is at least 21 °C. However, corals also die when the water gets too hot.

In the land-air environment and even in many parts of the aquatic environment, the temperature does not remain constant and can vary greatly depending on the season of the year or the time of day. In tropical areas, annual temperature variations may be even less noticeable than daily ones. Conversely, in temperate areas, temperatures vary significantly between seasons. Animals and plants are forced to adapt to the unfavorable winter season, during which active life is difficult or simply impossible. In tropical areas such adaptations are less pronounced. During a cold period with unfavorable temperature conditions, there seems to be a pause in the life of many organisms: hibernation in mammals, shedding of leaves in plants, etc. Some animals make long migrations to places with a more suitable climate.
The example of temperature shows that this factor is tolerated by the body only within certain limits. The organism dies if the environmental temperature is too low or too high. In environments where temperatures are close to these extremes, living inhabitants are rare. However, their number increases as the temperature approaches the average value, which is the best (optimal) for a given species.

Humidity

For most of its history, wildlife was represented exclusively by aquatic forms of organisms. Having conquered land, they, however, did not lose their dependence on water. Water is an integral part of the vast majority of living things: it is necessary for their normal functioning. A normally developing organism constantly loses water and therefore cannot live in completely dry air. Sooner or later, such losses can lead to the death of the body.
In physics, humidity is measured by the amount of water vapor in the air. However, the simplest and most convenient indicator characterizing the humidity of a particular area is the amount of precipitation falling there over a year or another period of time.
Plants extract water from the soil using their roots. Lichens can capture water vapor from the air. Plants have a number of adaptations that ensure minimal water loss. All land animals require periodic supply of water to compensate for the inevitable loss of water due to evaporation or excretion. Many animals drink water; others, such as amphibians, some insects and ticks, absorb it in a liquid or vapor state through their body coverings. Most desert animals never drink. They satisfy their needs from water supplied with food. Finally, there are animals that obtain water in an even more complex way through the process of fat oxidation. Examples include the camel and certain types of insects, such as rice and granary weevils, and clothes moths, which feed on fat. Animals, like plants, have many adaptations to save water.

Light

For animals, light as an environmental factor is incomparably less important than temperature and humidity. But light is absolutely necessary for living nature, since it serves as practically the only source of energy for it.
For a long time, a distinction has been made between light-loving plants, which are able to develop only under the sun's rays, and shade-tolerant plants, which are able to grow well under the forest canopy. Most of the undergrowth in the beech forest, which is particularly shady, is formed by shade-tolerant plants. This is of great practical importance for the natural regeneration of the forest stand: young shoots of many tree species are able to develop under the cover of large trees. In many animals, normal lighting conditions manifest themselves in a positive or negative reaction to light.

However, light has the greatest ecological significance in the cycle of day and night. Many animals are exclusively diurnal (most passerines), others are exclusively nocturnal (many small rodents, bats). Small crustaceans, floating in the water column, stay in surface waters at night, and during the day they descend to the depths, avoiding too bright light.
Compared to temperature or humidity, light has little direct effect on animals. It only serves as a signal for the restructuring of processes occurring in the body, which allows them to best respond to ongoing changes in external conditions.

The factors listed above do not exhaust the set of environmental conditions that determine the life and distribution of organisms. The so-called secondary climatic factors, for example, wind, atmospheric pressure, altitude above sea level, are important. Wind has an indirect effect: increasing evaporation, increasing dryness. Strong winds contribute to cooling. This action is important in cold places, high mountains or polar regions.

The heat factor (temperature conditions) significantly depends on the climate and the microclimate of the phytocenosis, however, orography and the nature of the soil surface play an equally important role; the humidity factor (water) also primarily depends on climate and microclimate (precipitation, relative humidity, etc.), but orography and biotic influences play an equally important role; In the action of the light factor, climate plays the main role, but orography (for example, slope exposure) and biotic factors (for example, shading) are no less important. The properties of the soil here are almost insignificant; chemistry (including oxygen) primarily depends on the soil, as well as on the biotic factor (soil microorganisms, etc.), however, the climatic state of the atmosphere is also important; finally, mechanical factors primarily depend on biotic ones (trampling, haymaking, etc.), but here orography (slope fall) and climatic influences (for example, hail, snow, etc.) are of a certain importance.

Based on their mode of action, environmental factors can be divided into direct (i.e., directly affecting the body) and indirect (affecting other factors). But one and the same factor can be directly acting in some conditions, and indirectly acting in others. Moreover, sometimes indirectly acting factors can have a very large (determining) significance, changing the combined effect of other, directly acting, factors (for example, geological structure, altitude, slope exposure, etc.).

Here are some more types of classification of environmental factors.

1. Constant factors (factors that do not change) - solar radiation, atmospheric composition, gravity, etc.
2. Factors that change. They are divided into periodic (temperature - seasonal, daily, annual; ebb and flow, lighting, humidity) and non-periodic (wind, fire, thunderstorm, all forms of human activity).

Classification by consumption:

Resources - elements of the environment that the body consumes, reducing their supply in the environment (water, CO2, O2, light)
Conditions are elements of the environment that are not consumed by the body (temperature, air movement, soil acidity).

Classification by direction:

Vectorized - directionally changing factors: waterlogging, soil salinization
Perennial-cyclical - with alternating multi-year periods of strengthening and weakening of a factor, for example climate change in connection with the 11-year solar cycle
Oscillatory (pulse, fluctuation) - fluctuations in both directions from a certain average value (daily fluctuations in air temperature, changes in the average monthly precipitation throughout the year)

By frequency they are divided into:
- periodic (regularly repeated): primary and secondary
- non-periodic (occur unexpectedly).



Surely each of us has noticed how plants of the same species develop well in the forest, but do not feel well in open spaces. Or, for example, some mammal species have large populations while others are more limited under seemingly identical conditions. All life on Earth is one way or another subject to its own laws and rules. Ecology studies them. One of the fundamental statements is Liebig's law of minimum

Limiting what is it?

The German chemist and founder of agricultural chemistry, Professor Justus von Liebig, made many discoveries. One of the most famous and recognized is the discovery of the fundamental limiting factor. It was formulated in 1840 and later expanded and generalized by Shelford. The law states that for any living organism, the most significant factor is the one that deviates the most from its optimal value. In other words, the existence of an animal or plant depends on the degree of severity (minimum or maximum) of a particular condition. Individuals encounter a wide variety of limiting factors throughout their lives.

"Liebig Barrel"

The factor limiting the life activity of organisms can be different. The formulated law is still actively used in agriculture. J. Liebig established that plant productivity depends primarily on the mineral substance (nutrient), which is most poorly expressed in the soil. For example, if nitrogen in the soil is only 10% of the required norm, and phosphorus is 20%, then the factor limiting normal development is the lack of the first element. Therefore, nitrogen-containing fertilizers should be initially applied to the soil. The meaning of the law was stated as clearly and clearly as possible in the so-called “Liebig barrel” (pictured above). Its essence is that when the vessel is filled, water begins to overflow where the shortest board is, and the length of the rest no longer matters much.

Water

This factor is the most stringent and significant compared to the others. Water is the basis of life, as it plays an important role in the life of an individual cell and the entire organism as a whole. Maintaining its quantity at the proper level is one of the main physiological functions of any plant or animal. Water as a factor limiting life activity is due to the uneven distribution of moisture over the Earth’s surface throughout the year. In the process of evolution, many organisms have adapted to the economical use of moisture, surviving the dry period in a state of hibernation or dormancy. This factor is most strongly expressed in deserts and semi-deserts, where flora and fauna are very sparse and unique.

Light

Light arriving in the form of solar radiation powers all life processes on the planet. Organisms care about its wavelength, duration of exposure, and radiation intensity. Depending on these indicators, the body adapts to environmental conditions. As a factor limiting existence, it is especially pronounced at great sea depths. For example, plants are no longer found at a depth of 200 m. Together with lighting, at least two more limiting factors “work” here: pressure and oxygen concentration. This can be counteracted by wet rainforests South America, as the most favorable territory for life.

Ambient temperature

It's no secret that all physiological processes occurring in the body depend on external and internal temperature. Moreover, most species are adapted to a rather narrow range (15-30 °C). The dependence is especially pronounced in organisms that are not able to independently maintain a constant body temperature, for example, reptiles. In the process of evolution, many adaptations have been formed that allow one to overcome this limited factor. So, in hot weather, in order to avoid overheating, it intensifies in plants through stomata, in animals - through the skin and respiratory system, as well as behavioral characteristics (hiding in the shade, burrows, etc.).

Pollutants

The significance cannot be underestimated. The last few centuries for humans have been marked by rapid technical progress and the rapid development of industry. This has led to harmful emissions into water bodies, soil and the atmosphere increasing several times. It is possible to understand which factor limits this or that species only after research. This state of affairs explains the fact that the species diversity of individual regions or areas has changed beyond recognition. Organisms change and adapt, some replace others.

All these are the main factors limiting life. In addition to them, there are many others, which are simply impossible to list. Each species and even individual is individual, therefore the limiting factors will be very diverse. For example, the percentage of oxygen dissolved in water is important for trout; for plants, the quantitative and qualitative composition of pollinating insects, etc.

All living organisms have certain limits of endurance due to one or another limiting factor. Some are quite wide, others are narrow. Depending on this indicator, eurybionts and stenobionts are distinguished. The former are able to tolerate a large amplitude of fluctuations of various limiting factors. For example, living everywhere from the steppes to the forest-tundra, wolves, etc. Stenobionts, on the contrary, are able to withstand very narrow fluctuations, and these include almost all rain forest plants.