NON-STATE EDUCATIONAL INSTITUTION

HIGHER PROFESSIONAL EDUCATION

CAPITAL FINANCIAL AND HUMANITARIAN ACADEMY

Branch in Salekhard

Faculty of Civil Service and Finance

Specialty: State and municipal administration

Subject "Ecology of territories"

" Environmental factors of the environment "

Completed by a 2nd year student

Salekhard, 2011

Introduction

1. Habitat

2. Environmental factors

Conclusion

Bibliography

Introduction

The surrounding organic world is an integral part of the environment of every living being. The mutual relations of organisms are the basis for the existence of biocenoses and populations.

The living is inseparable from the environment. Each individual organism, being an independent biological system, is constantly in direct or indirect relations with various components and phenomena of its environment or, in other words, the habitat that affects the state and properties of organisms.

Environment is one of the basic ecological concepts, which means the whole range of elements and conditions surrounding the organism in that part of the space where the organism lives, everything among which it lives and with which it directly interacts. At the same time, organisms, having adapted to a certain set of specific conditions, gradually change these conditions in the course of their life activity, i.e. environment of its existence.

The purpose of the abstract is to understand the variety of environmental environmental factors, given that each factor is a combination of the corresponding environmental conditions and its resource (reserve in the environment).

1. Habitat

The habitat is that part of nature that surrounds a living organism and with which it directly interacts. The components and properties of the environment are diverse and changeable. Any living being lives in a complex, changing world, constantly adapting to it and regulating its life activity in accordance with its changes.

The habitat of an organism is a set of abiotic and biotic conditions of its life. The properties of the environment are constantly changing, and any creature, in order to survive, adapts to these changes.

The impact of the environment is perceived by organisms through environmental factors called environmental.

2. Environmental factors

Environmental factors are diverse. They may be necessary or, conversely, harmful to living beings, promote or hinder survival and reproduction. Environmental factors have a different nature and specificity of action. Among them are abiotic and biotic, anthropogenic (Fig. 1).

Abiotic factors are the whole set of factors of the inorganic environment that affect the life and distribution of animals and plants. Abiotic factors are temperature, light, radioactive radiation, pressure, air humidity, salt composition of water, wind, currents, terrain - these are all properties of inanimate nature that directly or indirectly affect living organisms. Among them, physical, chemical and edaphic are distinguished.

Fig.1. Environmental factors of the environment

Physical factors are those whose source is a physical state or phenomenon (mechanical, wave, etc.). For example, the temperature, if it is high, will cause a burn, if it is very low, frostbite. Other factors can also affect the effect of temperature: in water - current, on land - wind and humidity, etc.

But there are also physical factors of global impact on organisms, which include the natural geophysical fields of the Earth. It is well known, for example, the ecological impact of the magnetic, electromagnetic, radioactive and other fields of our planet.

Chemical factors are those that come from the chemical composition of the environment. For example, the salinity of the water. If it is high, life in the reservoir may be completely absent (Dead Sea), but at the same time, most marine organisms cannot live in fresh water. The life of animals on land and in water, etc. depends on the sufficiency of the oxygen content.

Edaphic factors, i.e. soil - this is a combination of chemical, physical and mechanical properties of soils and rocks that affect both the organisms living in them, i.e. those for which they are the habitat, and on the root system of plants. The influence of chemical components (biogenic elements), temperature, humidity, soil structure, humus content, etc. is well known. on the growth and development of plants.

Among abiotic factors, climatic (temperature, air humidity, wind, etc.) and hydrographic factors of the aquatic environment (water, current, salinity, etc.) are quite often distinguished.

These are already factors of living nature, or biotic factors.

Biotic factors are forms of influence of living beings on each other. Each organism constantly experiences the direct or indirect influence of other creatures, enters into contact with representatives of its own species and other species - plants, animals, microorganisms, depends on them and itself has an impact on them.

For example, in the forest, under the influence of vegetation, a special microclimate, or microenvironment, is created, where, in comparison with an open habitat, its own temperature and humidity regime is created: in winter it is several degrees warmer, in summer it is cooler and wetter. A special microenvironment also occurs in tree hollows, burrows, caves, etc.

Of particular note are the conditions of the microenvironment under the snow cover, which already has a purely abiotic nature. As a result of the warming effect of snow, which is most effective when it is at least 50-70 cm thick, small rodent animals live in its base, approximately in a 5-cm layer, in winter, since the temperature conditions are favorable for them here (from 0 to - 2 ° C). Thanks to the same effect, seedlings of winter cereals - rye, wheat - are preserved under the snow. Large animals - deer, elk, wolves, foxes, hares, etc. - also hide in the snow from severe frosts, lying down in the snow to rest.

Intraspecific interactions between individuals of the same species are made up of group and mass effects and intraspecific competition. Group and mass effects - terms proposed by D.B. Grasse (1944) denote the association of animals of the same species into groups of two or more individuals and the effect caused by overpopulation of the environment. Currently, these effects are most often referred to as demographic factors. They characterize the dynamics of the number and density of groups of organisms at the population level, which is based on intraspecific competition, which is fundamentally different from interspecific competition. It manifests itself mainly in the territorial behavior of animals that protect their nesting sites and a known area in the area. So are many birds and fish.

Interspecific relationships are much more diverse (Fig. 1). Two species living side by side may not influence each other at all, they may influence both favorably and unfavorably. Possible types of combinations and reflect different types of relationships:

Neutralism - both types are independent and have no effect on each other;

environmental factor habitat

competition - each of the species has an adverse effect on the other;

Mutualism - species cannot exist without each other;

protocooperation (commonwealth) - both species form a community, but can exist separately, although the community benefits both of them;

commensalism - one species, commensal, benefits from cohabitation, and the other species - the owner does not have any benefit (mutual tolerance);

amensalism - one species inhibits the growth and reproduction of another - amensal;

predation - a predatory species feeds on its prey.

Interspecific relationships underlie the existence of biotic communities (biocenoses).

Anthropogenic factors are forms of activity of human society that lead to a change in nature as a habitat for other species or directly affect their lives. In the course of human history, the development of first hunting, and then agriculture, industry, and transport has greatly changed the nature of our planet. The significance of anthropogenic impacts on the entire living world of the Earth continues to grow rapidly.

Although man influences wildlife through a change in abiotic factors and biotic relationships of species, the activities of people on the planet should be singled out as a special force that does not fit into the framework of this classification. At present, practically the fate of the living cover of the Earth, all kinds of organisms is in the hands of human society, depends on the anthropogenic influence on nature.

Modern environmental problems and the growing interest in ecology are associated with the action of anthropogenic factors.

Most factors change qualitatively and quantitatively over time. For example, climatic - during the day, season, by year (temperature, illumination, etc.).

Changes in environmental factors over time can be:

1) regularly-periodic, changing the strength of the impact in connection with the time of day, or the season of the year, or the rhythm of the tides in the ocean;

2) irregular, without a clear periodicity, for example, changes in weather conditions in different years, catastrophic phenomena - storms, downpours, landslides, etc.;

3) directed over known, sometimes long, periods of time, for example, during a cooling or warming of the climate, overgrowing of water bodies, constant grazing in the same area, etc.

Such a subdivision of factors is very important in studying the adaptability of organisms to living conditions. The lack or excess of environmental factors negatively affects the life of the organism. For each organism, there is a certain range of actions of the environmental factor (Fig. 2). The favorable force of influence is called the zone of optimum of the ecological factor or simply the optimum for organisms of a given species. The stronger the deviations from the optimum, the more pronounced the inhibitory effect of this factor on organisms (pessimum zone). The maximum and minimum tolerated values ​​of the factor are critical points, beyond which existence is no longer possible, death occurs. The limits of endurance between critical points are called the ecological valency of living beings in relation to a specific environmental factor.

Fig.2. Scheme of the action of environmental factors on living organisms.

Representatives of different species differ greatly from each other both in the position of the optimum and in ecological valency.

The ability of an organism to adapt to the action of environmental factors is called adaptation (lat. Adantatuo - adaptation).

The range between the minimum and maximum of the environmental factor determines the amount of endurance - tolerance (lat. Tolerantua - patience) to this factor.

Different organisms are characterized by different levels of tolerance.

Conclusion

The same environmental factor has a different meaning in the life of cohabiting organisms of different species. For example, a strong wind in winter is unfavorable for large, open-dwelling animals, but does not affect smaller ones that take refuge in burrows or under snow. The salt composition of the soil is important for plant nutrition, but is indifferent for most terrestrial animals, etc.

Some properties of the environment remain relatively constant over long periods of time in the evolution of species. Such are the force of gravity, the solar constant, the salt composition of the ocean, and the properties of the atmosphere.

Classifications of environmental factors are diverse due to the exceptional complexity, interconnectedness and interdependence of phenomena in nature. Along with the classification of environmental factors considered in this essay, there are many other (less common) ones that use other distinguishing features. So, there are factors that depend and do not depend on the number and density of organisms. For example, the effect of macroclimatic factors is not affected by the number of animals or plants, while epidemics (mass diseases) caused by pathogenic microorganisms depend on the number in a given territory. There are classifications in which all anthropogenic factors are classified as biological.

Bibliography

1. Berezina N.A. Ecology of plants: textbook. allowance for students. higher textbook institutions - M.: Publishing center "Academy", 2009. - 400 p.

2. Blinov L.N. Ecology. Basic concepts, terms, laws, schemes: Textbook. [Text] St. Petersburg: SPbGPU, 2006. - 90 p.

3. Gorelov A.A. Ecology: lecture notes [Text] - M.: Higher education, 2008. - 192 p.

4. Korobkin V.N., Peredelsky L.V. Ecology: a textbook for universities. - 12th, add. and reworked. - Rostov n / a: Phoenix, 2007. - 602 p.

5. Nikolaikin N.N. Ecology: A textbook for the challenge - 2nd ed., Revised. and additional - M.: Bustard, 2005. - 624 p.

6. Chernova N.M., Bylova A.M. General ecology [Text] M.: Bustard, 2006.

Environmental factors are individual components of the environment that affect the body. Abiotic Environmental factors Biotic Anthropogenic

These are, first of all, climatic (sunlight, temperature, air humidity) and local factors (relief, soil properties, salinity, currents, wind, radiation, etc.). These factors can affect the body directly or indirectly.

Biotic factors are all possible forms of influence of living organisms (plants, animals, fungi, bacteria, viruses) on each other.

Anthropogenic influence of a person is those forms of human activity that, influencing the environment, change the living conditions of living organisms or directly affect certain species of plants and animals.

Environmental conditions or ecological conditions are called abiotic environmental factors that change in time and space, to which organisms respond.

Temperature. Any organism is able to live only within a certain temperature range. Somewhere within this interval, the temperature conditions are most favorable for the existence of a given organism. As the temperature approaches the boundaries of the interval, the speed of life processes slows down and, finally, they stop altogether - the organism dies.

Light Since ancient times, light-loving and shade-tolerant plants have been distinguished. Many animals are exclusively diurnal (most passerines), others are exclusively nocturnal (many small rodents, bats).

Water Throughout most of its history, wildlife was represented exclusively by aquatic forms of organisms. Having conquered the land, they nevertheless did not lose their dependence on water. Water is an integral part of the vast majority of living beings: it is necessary for their normal functioning. A normally developing organism constantly loses water and therefore cannot live in absolutely dry air. Sooner or later, such losses can lead to the death of the body.

Plants take in water 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 need a periodic supply of water to compensate for the loss of water. Many animals drink water; others, such as amphibians, absorb it through the integument of the body. Most desert animals never drink.

Important are the so-called secondary climatic factors, such as wind, atmospheric pressure, altitude. The wind has an indirect effect: by increasing evaporation, it increases dryness. This action is important in cold places, in the highlands or in the polar regions.

General Laws of the Action of Environmental Factors on the Organism The law of optimum (lat. Optimum - "the best") reflects the reaction of species to a change in the strength of any factor. There are certain limits of action of each factor, within which the viability of organisms increases. This is the optimum zone. With deviations from this zone in the direction of decreasing or increasing the force of the impact of the factor, the viability of organisms decreases. This is a zone of oppression, or pessimum (lat. pessimus - "very bad"). If the action of the factor goes beyond certain, minimum or maximum limits possible for the species, the organisms die. The destructive value of the factor is called the critical point.

The law of optimum is of great practical importance. There are no entirely positive or negative factors, it all depends on their dosage. All forms of influence of the environment on organisms have a purely quantitative expression. In order to control the vital activity of a species, one should first of all prevent the exit of various environmental factors beyond their critical values ​​and try to maintain the optimum zone. This is very important for crop production, animal husbandry, forestry and, in general, all areas of human interaction with wildlife. The same rule applies to the person himself, especially in the field of medicine.

The use of the law of optimum is complicated by the fact that the optimal dosages of factors are different for each species. What is good for one species may be pessimistic or beyond critical limits for another. For example, at a temperature of 20 ° C, a tropical monkey shivers from the cold, and the northern inhabitant - the polar bear - languishes from the heat. Moth moths are still fluttering in November (at 6°C) when most other insects go into a torpor. Rice is grown in fields flooded with water, and wheat in such conditions gets wet and dies.

The law of ecological individuality of species reflects the diversity of the relationship of organisms with the environment. It testifies that in nature there are no two species with a complete coincidence of optima and critical points in relation to a set of environmental factors. If the species coincide in resistance to one factor, then they will certainly disperse in resistance to another. Ignorance of the law of ecological individuality of species, for example, in agricultural production, can lead to the death of organisms. When using mineral fertilizers, pesticides, these substances are often applied in excessive amounts, regardless of individual needs.

The law of the limiting factor is closely related to the law of optimum and follows from it. There are no entirely negative or positive factors in the environment: everything depends on the strength of their action. Living beings are simultaneously affected by many factors, and besides, most of them are changeable. But in each specific period of time, one can single out the most important factor on which life depends to the greatest extent. It turns out to be the environmental factor that most of all deviates from the optimum, i.e., limits the vital activity of organisms in a given period. Any factor influencing organisms can become either optimal or limiting, depending on the strength of its influence.

The law of the combined action of factors says: the result of the influence of any environmental factor on the vital activity of organisms largely depends on the combination and strength of others at the moment.

The law of indispensability of factors indicates that it is impossible to completely replace one factor with another. But often, with the complex influence of factors, one can see the substitution effect. For example, light cannot be replaced by excess heat or carbon dioxide, but by acting on changes in temperature, photosynthesis can be increased in plants. However, this is not a replacement of one factor by another, but a manifestation of a similar biological effect caused by changes in the quantitative indicators of the combined action of factors. This phenomenon is widely used in agriculture. For example, in greenhouses to produce products, they create an increased content of carbon dioxide and moisture in the air, heating, and thereby partly compensate for the lack of light in autumn and winter.

In the action of environmental factors on the planet, there is a periodicity associated with the time of day, the seasons of the year, sea tides and the phases of the moon. This periodicity is due to cosmic reasons - the movement of the Earth around its axis, around the Sun and interaction with the Moon. Life on Earth is adapted to this constantly existing rhythm, which is manifested in changes in the state and behavior of organisms.

Vegetation of plants, leaf fall, winter dormancy, reproduction of animals, their migrations, hibernation, fattening are examples of phenomena caused by the season of the year. The change of day and night causes changes in the activity of animals, the rate of photosynthesis in plants, etc.

The length of daylight is the only accurate signal of the approach of winter or spring, i.e., changes in the whole complex of environmental factors. Weather conditions are deceptive. Therefore, plants, for example, reacting to the length of the day, do not open their leaves during winter thaws and do not turn to leaf fall during short-term summer frosts. Plants also bloom at a certain length of the day. Plant flowering is one of the manifestations of photoperiodism. This is a common problem for growers. Therefore, among plants, it is important to distinguish between short-day and long-day species or varieties. Long-day plants are distributed mainly in temperate and subpolar latitudes, and short-day plants in areas closer to the equator.

The ability to perceive the length of the day and respond to it is especially widespread in the animal kingdom. In animals, photoperiodism controls fertility, the timing of the mating season, migration, and the transition to hibernation.

Questions 1. 2. 3. 4. 5. 6. 7. 8. 9. What are environmental factors? What groups are environmental factors divided into? What is called environmental conditions? What is the essence of the law of optimum? What value does it have? Why is it necessary to take into account the law of ecological individuality of species? What is the limiting factor? What is the essence of the law of joint action of factors? What is a substitution effect? What is photoperiodism?

Question 2. What effect does temperature have on different types of organisms?
Any kind of organisms is able to live only within a certain temperature range, within which the temperature conditions are most favorable for its existence, and its vital functions are carried out most actively. Temperature directly affects the rate of biochemical reactions in the bodies of living organisms, which proceed within certain limits. The temperature limits in which organisms usually live are from 0 to 50oC. But some bacteria and algae can live in hot springs at a temperature of 85-87°C. High temperatures (up to 80oC) are tolerated by some unicellular soil algae, scale lichens, and plant seeds. There are animals and plants that can withstand the effects of very low temperatures - until they freeze completely. As we approach the boundaries of the temperature interval, the speed of life processes slows down, and beyond its limits they stop altogether - the organism dies.
Most animals are cold-blooded (poikilothermic) organisms - their body temperature depends on the ambient temperature. These are all types of invertebrates and a significant part of vertebrates (fish, amphibians, reptiles).
Birds and mammals are warm-blooded (homeothermic) animals. Their body temperature is relatively constant and largely dependent on the metabolism of the organism itself. Also, these animals develop adaptations that allow them to retain body heat (hair, dense plumage, a thick layer of subcutaneous adipose tissue, etc.).
In most of the Earth's territory, temperature has clearly defined daily and seasonal fluctuations, which determines certain biological rhythms of organisms. The temperature factor also affects the vertical zonality of fauna and flora.

Question 3. How do animals and plants get the water they need?
Water- the main component of the cytoplasm of cells, is one of the most important factors affecting the distribution of terrestrial living organisms. Lack of water leads to a number of adaptations in plants and animals.
Plants use their roots to extract the water they need from the soil. Drought-resistant plants have a deep root system, smaller cells, and an increased concentration of cell sap. Water evaporation decreases as a result of leaf reduction, the formation of a thick cuticle or wax coating, etc. Many plants can absorb moisture from the air (lichens, epiphytes, cacti). A number of plants have a very short growing season (as long as there is moisture in the soil) - tulips, feather grass, etc. In dry times, they are dormant in the form of underground shoots - bulbs or rhizomes.
All terrestrial animals need a periodic supply to compensate for the inevitable loss of water due to evaporation or excretion. Many of them drink water, others, such as amphibians, some insects and mites, suck it up through the integument of the body in a liquid or vapor state. In terrestrial arthropods, dense covers are formed that prevent evaporation, metabolism is modified - insoluble products (uric acid, guanine) are released. Many inhabitants of deserts and steppes (turtles, snakes) hibernate during the drought period. A number of animals (insects, camels) use metabolic water for life, which is produced during the breakdown of fat. Many animal species make up for the lack of water by absorbing it when drinking or with food (amphibians, birds, mammals).

Question 4. How do organisms react to different illumination?
sunlight- the main source of energy for living organisms. The intensity of light (illuminance) for many organisms is a signal for the restructuring of processes occurring in the body, which allows them to best respond to ongoing changes in external conditions. Light is especially important for green plants. The biological effect of sunlight depends on its characteristics: spectral composition, intensity, daily and seasonal periodicity.
In many animals, light conditions cause a positive or negative reaction to light. Some insects (moths) flock to the light, others (cockroaches) avoid it. The change of day and night is of the greatest ecological importance. Many animals are exclusively diurnal (most birds), others are exclusively nocturnal (many small rodents, bats, etc.). Small crustaceans hovering in the water column stay at night in surface waters, and during the day they sink to the depths, avoiding too bright light.
The ultraviolet part of the spectrum has a high photochemical activity: in the animal body it is involved in the synthesis of vitamin D, these rays are perceived by the organs of vision of insects.
The visible part of the spectrum (red and blue rays) provides the process of photosynthesis, the bright color of flowers (attracting pollinators). In animals, visible light is involved in spatial orientation.
Infrared rays are a source of thermal energy. Heat is important for thermoregulation of cold-blooded animals (invertebrates and lower vertebrates). In plants, infrared radiation affects the enhancement of transpiration, which contributes to the absorption of carbon dioxide and the movement of water through the plant body.
Plants and animals respond to the ratio between the duration of the period of light and darkness during the day or season. This phenomenon is called photoperiodism. Photoperiodism regulates the daily and seasonal rhythms of life of organisms, and is also a climatic factor that determines the life cycles of many species. In plants, photoperiodism is manifested in the synchronization of the period of flowering and fruit ripening with the period of the most active photosynthesis; in animals - in the coincidence of the breeding season with an abundance of food, in bird migrations, a change in coat in mammals, falling into hibernation, changes in behavior, etc.

Question 5. How do pollutants act on organisms?
As a result of human activities, the environment is polluted by by-products of production. Such pollutants include: hydrogen sulfide, sulfur dioxide, salts of heavy metals (copper, lead, zinc, etc.), radionuclides, by-products of oil refining, etc. Especially in areas with developed industry, these substances can cause the death of organisms and stimulate the development of the mutation process, which can ultimately lead to an ecological disaster. Harmful substances found in water bodies, in the soil and in the atmosphere adversely affect plants, animals and humans.
Many pollutants act as poisons, causing entire plant or animal species to become extinct. Others can be passed along food chains, accumulate in the bodies of organisms, cause gene mutations, the significance of which can only be assessed in the future. Human life also becomes impossible in conditions of environmental pollution, because there are numerous direct poisonings with poisons, as well as side effects of a polluted environment (increase in infectious diseases, cancers and diseases of various organ systems). As a rule, pollution of nature leads to a decrease in species diversity and a violation of the stability of biocenoses.

LECTURE №4

TOPIC: ENVIRONMENTAL FACTORS

PLAN:

1. The concept of environmental factors and their classification.

2. Abiotic factors.

2.1. Ecological role of the main abiotic factors.

2.2. topographic factors.

2.3. space factors.

3. Biotic factors.

4. Anthropogenic factors.

1. The concept of environmental factors and their classification

Ecological factor - any element of the environment that can directly or indirectly affect a living organism, at least at one of the stages of its individual development.

Environmental factors are diverse, and each factor is a combination of the corresponding environmental conditions and its resource (reserve in the environment).

Environmental environmental factors are usually divided into two groups: factors of inert (non-living) nature - abiotic or abiogenic; factors of living nature - biotic or biogenic.

Along with the above classification of environmental factors, there are many others (less common) that use other distinguishing features. So, there are factors that depend and do not depend on the number and density of organisms. For example, the number of animals or plants does not affect the action of macroclimatic factors, while epidemics (mass diseases) caused by pathogenic microorganisms depend on their number in a given territory. Classifications are known in which all anthropogenic factors are classified as biotic.

2. Abiotic factors

In the abiotic part of the habitat (in inanimate nature), all factors, first of all, can be divided into physical and chemical. However, to understand the essence of the phenomena and processes under consideration, it is convenient to represent abiotic factors as a set of climatic, topographic, space factors, as well as characteristics of the composition of the environment (aquatic, terrestrial or soil), etc.

Physical factors- these are those whose source is a physical state or phenomenon (mechanical, wave, etc.). For example, the temperature, if it is high - there will be a burn, if it is very low - frostbite. Other factors can also affect the effect of temperature: in water - current, on land - wind and humidity, etc.

Chemical Factors are those that come from the chemical composition of the environment. For example, the salinity of water, if it is high, life in a reservoir may be completely absent (Dead Sea), but at the same time, most marine organisms cannot live in fresh water. The life of animals on land and in water depends on the adequacy of the oxygen content, etc.

Edaphic factors(soil) is a set of chemical, physical and mechanical properties of soils and rocks that affect both the organisms living in them, that is, for which they are the habitat, and the root system of plants. The effects of chemical components (biogenic elements), temperature, humidity, and soil structure on the growth and development of plants are well known.

2.1. Ecological role of the main abiotic factors

solar radiation. Solar radiation is the main source of energy for the ecosystem. The energy of the Sun propagates in space in the form of electromagnetic waves. For organisms, the wavelength of perceived radiation, its intensity and duration of exposure are important.

About 99% of the total energy of solar radiation is rays with a wavelength of k = nm, including 48% is in the visible part of the spectrum (k = nm), 45% is in the near infrared (k = nm) and about 7% is in the ultraviolet (k = nm).< 400 нм).

Rays with X = nm are of primary importance for photosynthesis. Long-wave (far infrared) solar radiation (k > 4000 nm) has little effect on the vital processes of organisms. Ultraviolet rays with k\u003e 320 nm in small doses are necessary for animals and humans, since under their action vitamin D is formed in the body. Radiation with k< 290 нм губи­тельно для живого, но до поверхности Земли оно не доходит, поглощаясь озоновым слоем атмосферы.

As it passes through atmospheric air, sunlight is reflected, scattered, and absorbed. Pure snow reflects approximately 80-95% of sunlight, polluted - 40-50%, chernozem soil - up to 5%, dry light soil - 35-45%, coniferous forests - 10-15%. However, the illumination of the earth's surface varies significantly depending on the time of year and day, geographic latitude, slope exposure, atmospheric conditions, etc.

Due to the rotation of the Earth, daylight and darkness alternate periodically. Flowering, seed germination in plants, migration, hibernation, animal reproduction and much more in nature are associated with the duration of the photoperiod (day length). The need for light for plants determines their rapid growth in height, the layered structure of the forest. Aquatic plants spread mainly in the surface layers of water bodies.

Direct or diffuse solar radiation is not required only by a small group of living beings - some types of fungi, deep-sea fish, soil microorganisms, etc.

The most important physiological and biochemical processes carried out in a living organism, due to the presence of light, include the following:

1. Photosynthesis (1-2% of the solar energy falling on the Earth is used for photosynthesis);

2. Transpiration (about 75% - for transpiration, which ensures the cooling of plants and the movement of aqueous solutions of mineral substances through them);

3. Photoperiodism (ensures the synchronism of life processes in living organisms to periodically changing environmental conditions);

4. Movement (phototropism in plants and phototaxis in animals and microorganisms);

5. Vision (one of the main analyzing functions of animals);

6. Other processes (synthesis of vitamin D in humans in the light, pigmentation, etc.).

The basis of the biocenoses of central Russia, like most terrestrial ecosystems, are producers. Their use of sunlight is limited by a number of natural factors and, first of all, by temperature conditions. In this regard, special adaptive reactions have been developed in the form of layering, mosaic leaves, phenological differences, etc. According to the requirements for lighting conditions, plants are divided into light-loving or photophilous (sunflower, plantain, tomato, acacia, melon), shady or non-light-loving (forest grasses, mosses) and shade-tolerant (sorrel, heather, rhubarb, raspberry, blackberry).

Plants form the conditions for the existence of other types of living beings. That is why their reaction to lighting conditions is so important. Environmental pollution leads to a change in illumination: a decrease in the level of solar insolation, a decrease in the amount of photosynthetically active radiation (PAR - part of solar radiation with a wavelength of 380 to 710 nm), a change in the spectral composition of light. As a result, this destroys cenoses based on the arrival of solar radiation in certain parameters.

Temperature. For the natural ecosystems of our zone, the temperature factor, along with light supply, is decisive for all life processes. The activity of populations depends on the time of year and time of day, since each of these periods has its own temperature conditions.

Temperature is mainly related to solar radiation, but in some cases is determined by the energy of geothermal sources.

At temperatures below the freezing point, a living cell is physically damaged by the resulting ice crystals and dies, and at high temperatures, denaturation of enzymes occurs. The vast majority of plants and animals cannot withstand negative body temperatures. The upper temperature limit of life rarely rises above 40–45 °C.

In the range between the extreme limits, the rate of enzymatic reactions (hence, the metabolic rate) doubles with every 10°C rise in temperature.

A significant part of organisms is able to control (maintain) body temperature, and primarily the most vital organs. Such organisms are called homeothermic- warm-blooded (from the Greek homoios - similar, therme - warmth), in contrast to poikilothermic- cold-blooded (from the Greek poikilos - various, changeable, diverse), having a variable temperature, depending on the ambient temperature.

Poikilothermic organisms in the cold season of the year or day reduce the level of vital processes up to anabiosis. This primarily concerns plants, microorganisms, fungi and poikilothermic (cold-blooded) animals. Only homoiothermic (warm-blooded) species remain active. Heterothermic organisms, being in an inactive state, have a body temperature not much higher than the temperature of the external environment; in the active state - quite high (bears, hedgehogs, bats, ground squirrels).

Thermoregulation of homoiothermic animals is provided by a special type of metabolism that goes with the release of heat in the body of animals, the presence of heat-insulating covers, size, physiology, etc.

As for plants, they have developed a number of properties in the process of evolution:

cold resistance– the ability to endure low positive temperatures for a long time (from 0°С to +5°С);

winter hardiness– the ability of perennial species to endure a complex of unfavorable winter conditions;

frost resistance- the ability to endure negative temperatures for a long time;

anabiosis- the ability to endure a period of prolonged lack of environmental factors in a state of a sharp decrease in metabolism;

heat resistance– the ability to endure high (over +38°…+40°С) temperatures without significant metabolic disorders;

ephemerality– reduction of ontogenesis (up to 2-6 months) in species growing under conditions of a short period of favorable temperature conditions.

In the aquatic environment, due to the high heat capacity of water, temperature changes are less abrupt and conditions are more stable than on land. It is known that in regions where the temperature varies greatly during the day, as well as in different seasons, the diversity of species is less than in regions with more constant daily and annual temperatures.

Temperature, like light intensity, depends on latitude, season, time of day, and slope exposure. Extreme temperatures (low and high) are exacerbated by strong winds.

The change in temperature as you rise in the air or dive into the aquatic environment is called temperature stratification. Usually, in both cases, a continuous decrease in temperature with a certain gradient is observed. However, there are other options as well. So, in summer, surface waters heat up more than deep ones. Due to a significant decrease in the density of water as it is heated, its circulation begins in the surface heated layer without mixing with the denser, colder water of the underlying layers. As a result, an intermediate zone with a sharp temperature gradient is formed between the warm and cold layers. All this affects the placement of living organisms in the water, as well as the transfer and dispersion of incoming impurities.

A similar phenomenon also occurs in the atmosphere, when the cooled layers of air move down and are located under the warm layers, i.e., there is a temperature inversion that contributes to the accumulation of pollutants in the surface air layer.

Inversions are facilitated by some features of the relief, such as pits and valleys. It occurs when there are substances at a certain height, such as aerosols, heated directly by direct solar radiation, which causes more intense heating of the upper air layers.

In the soil environment, daily and seasonal stability (fluctuations) of temperature depend on depth. A significant temperature gradient (as well as humidity) allows the inhabitants of the soil to provide themselves with a favorable environment with minor movements. The presence and abundance of living organisms can affect temperature. For example, under the canopy of a forest or under the leaves of an individual plant, there is a different temperature.

Precipitation, humidity. Water is essential for life on Earth, ecologically it is unique. Under almost the same geographical conditions on Earth, there are both a hot desert and a tropical forest. The difference is only in the annual amount of precipitation: in the first case, 0.2–200 mm, and in the second, 900–2000 mm.

Precipitation, closely related to air humidity, is the result of condensation and crystallization of water vapor in the high layers of the atmosphere. In the surface layer of air, dews and fogs form, and at low temperatures moisture crystallization is observed - frost falls.

One of the main physiological functions of any organism is to maintain an adequate level of water in the body. In the process of evolution, organisms have developed a variety of adaptations for obtaining and economical use of water, as well as for experiencing a dry period. Some desert animals get water from food, others through the oxidation of timely stored fats (for example, a camel, capable of obtaining 107 g of metabolic water from 100 g of fat by biological oxidation); at the same time, they have a minimum water permeability of the outer integument of the body, and dryness is characterized by falling into a state of rest with a minimum metabolic rate.

Land plants obtain water mainly from the soil. Low rainfall, rapid drainage, intense evaporation, or a combination of these factors lead to desiccation, and excess moisture leads to waterlogging and waterlogging of soils.

The moisture balance depends on the difference between the amount of precipitation and the amount of water evaporated from the surfaces of plants and soil, as well as by transpiration]. In turn, evaporation processes directly depend on the relative humidity of the atmospheric air. At a humidity close to 100%, evaporation practically stops, and if the temperature further decreases, then the reverse process begins - condensation (fog forms, dew falls, frost).

In addition to the above, air humidity as an environmental factor at its extreme values ​​(high and low humidity) enhances the effect (aggravates) the effect of temperature on the body.

Saturation of air with water vapor rarely reaches its maximum value. Humidity deficit - the difference between the maximum possible and actually existing saturation at a given temperature. This is one of the most important environmental parameters, since it characterizes two quantities at once: temperature and humidity. The higher the moisture deficit, the drier and warmer, and vice versa.

Precipitation regime is the most important factor determining the migration of pollutants in the natural environment and their leaching from the atmosphere.

In relation to the water regime, the following ecological groups of living beings are distinguished:

hydrobionts- inhabitants of ecosystems, the entire life cycle of which takes place in water;

hygrophytes– plants of wet habitats (marsh marigold, European swimsuit, broad-leaved cattail);

hygrophiles- animals living in very damp parts of ecosystems (mollusks, amphibians, mosquitoes, wood lice);

mesophytes– plants of moderately humid habitats;

xerophytes– plants of dry habitats (feather grass, wormwood, astragalus);

xerophiles- inhabitants of arid territories that cannot tolerate high humidity (some species of reptiles, insects, desert rodents and mammals);

succulents- plants of the most arid habitats, capable of accumulating significant moisture reserves inside the stem or leaves (cacti, aloe, agave);

sclerophytes– plants of very arid territories, capable of withstanding severe dehydration (common camel's thorn, saxaul, saksagyz);

ephemera and ephemeroids- annual and perennial herbaceous species with a shortened cycle, coinciding with a period of sufficient moisture.

Water consumption of plants can be characterized by the following indicators:

drought tolerance– ability to tolerate reduced atmospheric and (or) soil drought;

moisture resistance- the ability to tolerate waterlogging;

transpiration rate- the amount of water spent on the formation of a unit of dry mass (for white cabbage 500-550, for pumpkin-800);

coefficient of total water consumption- the amount of water consumed by the plant and soil to create a unit of biomass (for meadow grasses - 350–400 m3 of water per ton of biomass).

Violation of the water regime, pollution of surface waters is dangerous, and in some cases fatal for cenoses. Changes in the water cycle in the biosphere can lead to unpredictable consequences for all living organisms.

The mobility of the environment. The causes of the movement of air masses (wind) are primarily uneven heating of the earth's surface, causing pressure drops, as well as the rotation of the Earth. The wind is directed towards warmer air.

Wind is the most important factor in the spread of moisture, seeds, spores, chemical impurities, etc. over long distances. It contributes both to a decrease in the near-Earth concentration of dust and gaseous substances near the place of their entry into the atmosphere, and to an increase in background concentrations in the air due to emissions from distant sources, including transboundary transport.

The wind accelerates transpiration (evaporation of moisture by the ground parts of plants), which especially worsens the conditions of existence at low humidity. In addition, it indirectly affects all living organisms on land, participating in the processes of weathering and erosion.

Mobility in space and mixing of water masses contribute to maintaining the relative homogeneity (homogeneity) of the physical and chemical characteristics of water bodies. The average speed of surface currents lies in the range of 0.1-0.2 m/s, reaching 1 m/s in some places, and 3 m/s near the Gulf Stream.

Pressure. Normal atmospheric pressure is considered to be an absolute pressure at the level of the World Ocean surface of 101.3 kPa, corresponding to 760 mm Hg. Art. or 1 atm. Within the globe there are constant areas of high and low atmospheric pressure, and at the same points seasonal and daily fluctuations are observed. As the altitude increases relative to the ocean level, the pressure decreases, the partial pressure of oxygen decreases, and transpiration in plants increases.

Periodically, areas of low pressure are formed in the atmosphere with powerful air currents moving in a spiral towards the center, which are called cyclones. They are characterized by high rainfall and unstable weather. Opposite natural phenomena are called anticyclones. They are characterized by stable weather, light winds and, in some cases, temperature inversion. During anticyclones, sometimes unfavorable meteorological conditions arise, which contribute to the accumulation of pollutants in the surface layer of the atmosphere.

There are also sea and continental atmospheric pressure.

The pressure in the aquatic environment increases as you dive. Due to the significantly (800 times) greater density of water than air, for every 10 m of depth in a freshwater reservoir, the pressure increases by 0.1 MPa (1 atm). The absolute pressure at the bottom of the Mariana Trench exceeds 110 MPa (1100 atm).

ionizingradiation. Ionizing radiation is the radiation that forms pairs of ions when passing through a substance; background - radiation created by natural sources. It has two main sources: cosmic radiation and radioactive isotopes, and elements in the minerals of the earth's crust, which arose sometime in the process of formation of the Earth's substance. Due to the long half-life, the nuclei of many primordial radioactive elements have survived in the bowels of the Earth to this day. The most important of them are potassium-40, thorium-232, uranium-235 and uranium-238. Under the influence of cosmic radiation in the atmosphere, more and more new nuclei of radioactive atoms are constantly formed, the main of which are carbon-14 and tritium.

The radiation background of the landscape is one of the indispensable components of its climate. All known sources of ionizing radiation take part in the formation of the background, but the contribution of each of them to the total radiation dose depends on a specific geographical point. Man, as an inhabitant of the natural environment, receives the bulk of exposure from natural sources of radiation, and it is impossible to avoid this. All living things on Earth are exposed to radiation from the Cosmos. Mountain landscapes, due to their significant height above sea level, are characterized by an increased contribution of cosmic radiation. Glaciers, acting as an absorbing screen, retain in their mass the radiation of the underlying bedrock. Differences in the content of radioactive aerosols over the sea and land were found. The total radioactivity of sea air is hundreds and thousands of times less than that of continental air.

There are areas on the Earth where the exposure dose rate is ten times higher than the average values, for example, areas of uranium and thorium deposits. Such places are called uranium and thorium provinces. A stable and relatively higher level of radiation is observed in the outcrops of granite rocks.

Biological processes accompanying the formation of soils significantly affect the accumulation of radioactive substances in the latter. With a low content of humic substances, their activity is weak, while chernozems have always been distinguished by a higher specific activity. It is especially high in chernozem and meadow soils located close to granite massifs. According to the degree of increase in the specific activity of the soil, it can be tentatively arranged in the following order: peat; chernozem; soils of the steppe zone and forest-steppe; soils developing on granites.

The effect of periodic fluctuations in the intensity of cosmic radiation near the earth's surface on the radiation dose of living organisms is practically insignificant.

In many regions of the globe, the exposure dose rate due to the radiation of uranium and thorium reaches the level of exposure that existed on Earth in a geologically observable time, at which the natural evolution of living organisms took place. In general, ionizing radiation has a more detrimental effect on highly developed and complex organisms, and a person is particularly sensitive. Some substances are evenly distributed throughout the body, such as carbon-14 or tritium, while others accumulate in certain organs. So, radium-224, -226, lead-210, polonium-210 accumulate in bone tissues. The inert gas radon-220 has a strong effect on the lungs, sometimes released not only from deposits in the lithosphere, but also from minerals mined by man and used as building materials. Radioactive substances can accumulate in water, soil, precipitation or air if the rate of their entry exceeds the rate of radioactive decay. In living organisms, the accumulation of radioactive substances occurs when they are ingested with food.

2.2. Topographic factors

The influence of abiotic factors largely depends on the topographic characteristics of the area, which can greatly change both the climate and the features of soil development. The main topographic factor is the height above sea level. With altitude, average temperatures decrease, the daily temperature difference increases, the amount of precipitation, wind speed and radiation intensity increase, and pressure decreases. As a result, vertical zonality of vegetation distribution is observed in mountainous areas, corresponding to the sequence of changes in latitudinal zones from the equator to the poles.

Mountain ranges can serve as climatic barriers. Rising above the mountains, the air cools, which often causes precipitation and thus reduces its absolute moisture content. Getting then to the other side of the mountain range, the dried air helps to reduce the intensity of rain (snowfall), which creates a "rain shadow".

Mountains can play the role of an isolating factor in the processes of speciation, as they serve as a barrier to the migration of organisms.

An important topographical factor is exposition(illuminance) of the slope. In the Northern Hemisphere it is warmer on the southern slopes, while in the Southern Hemisphere it is warmer on the northern slopes.

Another important factor is slope steepness affecting drainage. Water flows down the slopes, washing away the soil, reducing its layer. In addition, under the influence of gravity, the soil slowly slides down, which leads to its accumulation at the base of the slopes. The presence of vegetation inhibits these processes, however, at slopes of more than 35°, soil and vegetation are usually absent and screes of loose material are created.

2.3. Space factors

Our planet is not isolated from the processes taking place in outer space. The Earth periodically collides with asteroids, approaches comets, cosmic dust, meteorite substances fall on it, various types of radiation from the Sun and stars. Cyclically (one of the cycles has a period of 11.4 years), solar activity changes.

Science has accumulated many facts confirming the influence of the Cosmos on the life of the Earth.

3. Biotic factors

All living things that surround an organism in a habitat constitute a biotic environment or biota. Biotic factors- is a set of influences of the vital activity of some organisms on others.

The relationships between animals, plants, and microorganisms are extremely diverse. First of all, distinguish homotypic reactions, i.e., the interaction of individuals of the same species, and heterotypic- relations between representatives of different species.

Representatives of each species are able to exist in such a biotic environment, where connections with other organisms provide them with normal living conditions. The main form of manifestation of these relationships is the nutritional relationships of organisms of various categories, which form the basis of food (trophic) chains, networks and the trophic structure of the biota.

In addition to food relations, spatial relationships also arise between plant and animal organisms. As a result of the action of many factors, diverse species are not united in an arbitrary combination, but only under the condition of adaptation to cohabitation.

Biotic factors manifest themselves in biotic relationships.

The following forms of biotic relationships are distinguished.

Symbiosis(cohabitation). This is a form of relationship in which both partners or one of them benefit from the other.

Cooperation. Cooperation is a long-term, inseparable mutually beneficial cohabitation of two or more species of organisms. For example, the relationship of a hermit crab and sea anemone.

Commensalism. Commensalism is an interaction between organisms, when the vital activity of one delivers food (freeloading) or shelter (lodging) to another. Typical examples are hyenas picking up the remains of half-eaten prey by lions, fish fry hiding under the umbrellas of large jellyfish, as well as some mushrooms growing at the roots of trees.

Mutualism. Mutualism is a mutually beneficial cohabitation, when the presence of a partner becomes a prerequisite for the existence of each of them. An example is the cohabitation of nodule bacteria and leguminous plants, which can live together on nitrogen-poor soils and enrich the soil with it.

Antibiosis. A form of relationship in which both partners or one of them are negatively affected is called antibiosis.

Competition. This is the negative impact of organisms on each other in the struggle for food, habitat and other conditions necessary for life. It manifests itself most clearly at the population level.

Predation. Predation is a relationship between a predator and a prey, which consists in eating one organism by another. Predators are animals or plants that catch and eat animals for food. So, for example, lions eat herbivorous ungulates, birds - insects, large fish - smaller ones. Predation is both beneficial to one organism and harmful to another.

At the same time, all these organisms need each other. In the process of “predator-prey” interaction, natural selection and adaptive variability occur, i.e., the most important evolutionary processes. Under natural conditions, no species tends (and cannot) lead to the destruction of another. Moreover, the disappearance of any natural "enemy" (predator) from the habitat can contribute to the extinction of its prey.

Neutralism. The mutual independence of different species living in the same territory is called neutralism. For example, squirrels and moose do not compete with each other, but drought in the forest affects both, although to different degrees.

Recently, more and more attention has been paid to anthropogenic factors- a set of human impacts on the environment, due to its urban-technogenic activities.

4. Anthropogenic factors

The current stage of human civilization reflects such a level of knowledge and capabilities of mankind that its impact on the environment, including biological systems, acquires the character of a global planetary force, which we single out into a special category of factors - anthropogenic, i.e. generated by human activity. These include:

Changes in the Earth's climate as a result of natural geological processes, enhanced by the greenhouse effect caused by changes in the optical properties of the atmosphere, mainly by emissions of CO, CO2, and other gases into it;

Debris in near-Earth space (NES), the consequences of which have not yet been fully understood, except for the real danger to spacecraft, including communication satellites, locations of the earth's surface, and others that are widely used in modern systems of interaction between people, states and governments;

Reducing the power of the stratospheric ozone screen with the formation of so-called “ozone holes”, which reduce the protective capabilities of the atmosphere against the ingress of hard short-wave ultraviolet radiation dangerous to living organisms to the Earth's surface;

Chemical pollution of the atmosphere with substances that contribute to the formation of acid precipitation, photochemical smog and other compounds that are dangerous for biospheric objects, including humans and artificial objects created by them;

Pollution of the ocean and changes in the properties of ocean waters due to oil products, their saturation with carbon dioxide of the atmosphere, which in turn is polluted by vehicles and thermal power engineering, burial of highly toxic chemical and radioactive substances in ocean waters, pollution from river runoff, disturbance of the water balance of coastal areas due to river regulation;

Depletion and pollution of all kinds of springs and land waters;

Radioactive contamination of individual sites and regions with a tendency to spread over the Earth's surface;

Soil pollution due to polluted precipitation (eg acid rain), suboptimal use of pesticides and mineral fertilizers;

Changes in the geochemistry of landscapes, in connection with thermal power engineering, the redistribution of elements between the bowels and the surface of the Earth as a result of mining and smelting redistribution (for example, the concentration of heavy metals) or the extraction of anomalous, highly mineralized groundwater and brines to the surface;

Continued accumulation on the surface of the Earth of household garbage and all kinds of solid and liquid waste;

Violation of the global and regional ecological balance, the ratio of ecological components in the coastal part of the land and the sea;

The continuing, and in some places - increasing desertification of the planet, the deepening of the process of desertification;

Reducing the area of ​​tropical forests and northern taiga, these main sources of maintaining the oxygen balance of the planet;

Release as a result of all the above processes of ecological niches and filling them with other species;

Absolute overpopulation of the Earth and relative demographic overpopulation of certain regions, extreme differentiation of poverty and wealth;

Deterioration of the living environment in overcrowded cities and metropolitan areas;

The exhaustion of many mineral deposits and the gradual transition from rich to ever poorer ores;

Strengthening social instability, as a result of the increasing differentiation of the rich and poor part of the population of many countries, the increase in the level of armament of their population, criminalization, natural environmental disasters.

Decrease in the immune status and health status of the population of many countries of the world, including Russia, repeated repetition of epidemics, which are becoming more massive and severe in their consequences.

This is by no means a complete circle of problems, in solving each of which a specialist can find his place and work.

The most large-scale and significant is the chemical pollution of the environment by substances of a chemical nature unusual for it.

The physical factor as a pollutant of human activity is an unacceptable level of thermal pollution (especially radioactive).

Biological pollution of the environment is a variety of microorganisms, the most dangerous among which are various diseases.

Control questions And tasks

1. What are environmental factors?

2. What environmental factors are classified as abiotic, which are biotic?

3. What is the name of the totality of the influences of the life activity of some organisms on the life activity of others?

4. What are the resources of living beings, how are they classified and what is their ecological significance?

5. What factors should be taken into account in the first place when creating ecosystem management projects. Why?

We begin our acquaintance with ecology, perhaps, with one of the most developed and studied sections - autecology. The attention of autecology focuses on the interaction of individuals or groups of individuals with the conditions of their environment. Therefore, the key concept of autecology is the ecological factor, that is, the environmental factor that affects the body.

No environmental protection measures are possible without studying the optimum effect of one or another factor on a given biological species. In fact, how to protect this or that species, if you do not know what living conditions he prefers. Even the "protection" of such a species as a reasonable person requires knowledge of sanitary and hygienic standards, which are nothing more than the optimum of various environmental factors in relation to a person.

The influence of the environment on the body is called the environmental factor. The exact scientific definition is:

ECOLOGICAL FACTOR - any environmental condition to which the living reacts with adaptive reactions.

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

By their nature, environmental factors are divided into at least three groups:

abiotic factors - the influence of inanimate nature;

biotic factors - influences of living nature.

anthropogenic factors - influences caused by reasonable and unreasonable human activity ("anthropos" - a person).

Man modifies animate and inanimate nature, and in a certain sense takes on a geochemical role (for example, releasing carbon immured in the form of coal and oil for many millions of years and releasing it into the air with carbon dioxide). Therefore, anthropogenic factors in terms of scope and global impact are approaching geological forces.

Not infrequently, environmental factors are also subjected to a more detailed classification, when it is necessary to point to a particular group of factors. For example, there are climatic (relating to climate), edaphic (soil) environmental factors.

As a textbook example of the indirect action of environmental factors, the so-called bird colonies, which are huge concentrations of birds, are cited. The high density of birds is explained by a whole chain of cause and effect relationships. Bird droppings enter the water, organic substances in the water are mineralized by bacteria, an increased concentration of minerals leads to an increase in the number of algae, and after them - zooplankton. The lower crustaceans included in the zooplankton are fed by fish, and the birds inhabiting the bird rookery feed on fish. The chain closes. Bird droppings act as an environmental factor that indirectly increases the number of bird colonies.

How to compare the action of factors so different in nature? Despite the huge number of factors, from the very definition of the environmental factor as an element of the environment that affects the body, something in common follows. Namely: the action of environmental factors is always expressed in a change in the vital activity of organisms, and in the end, it leads to a change in the size of the population. This makes it possible to compare the effect of various environmental factors.

Needless to say, the effect of a factor on an individual is determined not by the nature of the factor, but by its dose. In the light of the above, and even simple life experience, it becomes obvious that the effect is determined precisely by the dose of the factor. Indeed, what is the factor "temperature"? This is quite an abstraction, but if you say that the temperature is -40 Celsius - there is no time for abstractions, it would be better to wrap yourself in everything warm! On the other hand, +50 degrees will not seem much better to us.

Thus, the factor affects the body with a certain dose, and among these doses, one can distinguish the minimum, maximum and optimal doses, as well as those values ​​at which the life of an individual stops (they are called lethal, or lethal).

The effect of various doses on the population as a whole is very clearly described graphically:

The ordinate axis plots the population size depending on the dose of one or another factor (abscissa axis). The optimal doses of the factor and the doses of the action of the factor are distinguished, at which the inhibition of the vital activity of the given organism occurs. On the graph, this corresponds to 5 zones:

optimum zone

to the right and left of it are the pessimum zones (from the border of the optimum zone to max or min)

lethal zones (beyond max and min) in which the population is 0.

The range of values ​​of the factor, beyond which the normal life of individuals becomes impossible, is called the limits of endurance.

In the next lesson, we will look at how organisms differ in relation to various environmental factors. In other words, the next lesson will focus on the ecological groups of organisms, as well as the Liebig barrel and how all this is related to the definition of MPC.

Glossary

FACTOR ABIOTIC - a condition or set of conditions of the inorganic world; ecological factor of inanimate nature.

ANTHROPOGENIC FACTOR - an environmental factor that owes its origin to human activity.

PLANKTON - a set of organisms that live in the water column and are unable to actively resist the transfer of currents, that is, "floating" in the water.

BIRD MARKET - a colonial settlement of birds associated with the aquatic environment (guillemots, gulls).

What ecological factors out of all their variety does the researcher pay attention to first of all? Not infrequently, a researcher is faced with the task of identifying those environmental factors that inhibit the vital activity of representatives of a given population, limit growth and development. For example, it is necessary to find out the reasons for the decline in the yield or the reasons for the extinction of the natural population.

With all the variety of environmental factors and the difficulties that arise when trying to assess their joint (complex) impact, it is important that the factors that make up the natural complex are of unequal importance. Back in the 19th century, Liebig (Liebig, 1840), studying the effect of various microelements on plant growth, established that plant growth is limited by the element whose concentration is at a minimum. The deficient factor was called the limiting factor. Figuratively, this position helps to present the so-called "Liebig's barrel".

Liebig barrel

Imagine a barrel with wooden slats on the sides of different heights, as shown in the picture. It is clear, no matter how high the other slats are, but you can pour water into the barrel exactly as much as the length of the shortest slat (in this case, 4 dies).

It remains only to "replace" some terms: let the height of the poured water be some biological or ecological function (for example, productivity), and the height of the rails will indicate the degree of deviation of the dose of one or another factor from the optimum.

At present Liebig's law of the minimum is interpreted more widely. A limiting factor can be a factor that is not only in short supply, but also in excess.

The environmental factor plays the role of a LIMITING FACTOR if this factor is below the critical level or exceeds the maximum tolerable level.

The limiting factor determines the distribution area of ​​the species or (under less severe conditions) affects the general level of metabolism. For example, the content of phosphates in sea water is a limiting factor that determines the development of plankton and the overall productivity of communities.

The concept of "limiting factor" applies not only to various elements, but to all environmental factors. Competitive relations often act as a limiting factor.

Each organism has its own limits of endurance in relation to various environmental factors. Depending on how wide or narrow these limits are, eurybiont and stenobiont organisms are distinguished. Eurybionts are able to endure a wide range of intensity of various environmental factors. For example, the habitat of a fox is from the forest-tundra to the steppes. Stenobionts, on the contrary, endure only very narrow fluctuations in the intensity of the environmental factor. For example, almost all tropical rainforest plants are stenobionts.

It is not uncommon to indicate which factor is meant. So, we can talk about eurythermal (tolerating large temperature fluctuations) organisms (many insects) and stenothermal (for tropical forest plants, temperature fluctuations within +5 ... +8 degrees C can be fatal); eury / stenohaline (tolerating / not tolerating fluctuations in water salinity); evry / stenobats (living in wide / narrow limits of the depth of the reservoir) and so on.

The emergence of stenobiont species in the process of biological evolution can be considered as a form of specialization in which greater efficiency is achieved at the expense of adaptability.

Interaction of factors. MPC.

With the independent action of environmental factors, it is sufficient to operate with the concept of "limiting factor" in order to determine the combined effect of a complex of environmental factors on a given organism. However, in real conditions, environmental factors can enhance or weaken each other. For example, frost in the Kirov region is easier to bear than in St. Petersburg, since the latter has higher humidity.

Accounting for the interaction of environmental factors is an important scientific problem. There are three main types of interaction factors:

additive - the interaction of factors is a simple algebraic sum of the effects of each of the factors with an independent action;

synergistic - the joint action of factors enhances the effect (that is, the effect of their joint action is greater than the simple sum of the effects of each factor with independent action);

antagonistic - the joint action of factors weakens the effect (that is, the effect of their joint action is less than the simple sum of the effects of each factor).

Why is it important to know about the interaction of environmental factors? The theoretical substantiation of the value of maximum allowable concentrations (MPC) of pollutants or maximum allowable levels (MPL) of the impact of polluting agents (for example, noise, radiation) is based on the law of the limiting factor. MPC is set experimentally at a level at which pathological changes do not yet occur in the body. At the same time, there are difficulties (for example, most often it is necessary to extrapolate data obtained on animals to humans). However, this is not about them.

It is not uncommon to hear how environmental authorities happily report that the level of most pollutants in the city's atmosphere is within the MPC. At the same time, the State Sanitary and Epidemiological Supervision authorities state an increased level of respiratory diseases in children. The explanation could be like this. It is no secret that many atmospheric pollutants have a similar effect: they irritate the mucous membranes of the upper respiratory tract, provoke respiratory diseases, etc. And the joint action of these pollutants gives an additive (or synergistic) effect.

Therefore, ideally, when developing MPC standards and assessing the existing environmental situation, the interaction of factors should be taken into account. Unfortunately, in practice this can be very difficult to do: it is difficult to plan such an experiment, it is difficult to evaluate the interaction, plus the tightening of MPCs has negative economic effects.

Glossary

MICROELEMENTS - chemical elements necessary for organisms in negligible quantities, but determining the success of their development. M. in the form of microfertilizers is used to increase the yield of plants.

LIMITING FACTOR - a factor that sets the framework (determining) for the course of some process or for the existence of an organism (species, community).

AREAL - the area of ​​distribution of any systematic group of organisms (species, genus, family) or a certain type of community of organisms (for example, the area of ​​lichen pine forests).

METABOLISM - (in relation to the body) consistent consumption, transformation, use, accumulation and loss of substances and energy in living organisms. Life is possible only through metabolism.

eurybiont - an organism that lives in various environmental conditions

STENOBIONT - an organism that requires strictly defined conditions of existence.

XENOBIOTIC - a chemical substance alien to the body, naturally not included in the biotic cycle. As a rule, a xenobiotic is of anthropogenic origin.

Ecosystem

URBAN AND INDUSTRIAL ECOSYSTEMS

General characteristics of urban ecosystems.

Urban ecosystems are heterotrophic, the share of solar energy fixed by urban plants or solar panels located on the roofs of houses is insignificant. The main sources of energy for the enterprises of the city, heating and lighting of the apartments of the townspeople are located outside the city. These are deposits of oil, gas, coal, hydro and nuclear power plants.

The city consumes a huge amount of water, only a small part of which a person uses for direct consumption. The main part of the water is spent on production processes and domestic needs. Personal water consumption in cities ranges from 150 to 500 liters per day, and taking into account industry, one citizen accounts for up to 1000 liters per day. The water used by cities is returned to nature in a polluted state - it is saturated with heavy metals, oil residues, complex organic substances like phenol, etc. It may contain pathogens. The city emits toxic gases and dust into the atmosphere, concentrates toxic waste in landfills, which, with spring water flows, enter aquatic ecosystems. Plants, as part of urban ecosystems, grow in parks, gardens, and lawns, their main purpose is to regulate the gas composition of the atmosphere. They release oxygen, absorb carbon dioxide and purify the atmosphere from harmful gases and dust that enter it during the operation of industrial enterprises and transport. Plants are also of great aesthetic and decorative value.

Animals in the city are represented not only by species common in natural ecosystems (birds live in parks: redstart, nightingale, wagtail; mammals: voles, squirrels and representatives of other groups of animals), but also by a special group of urban animals - human companions. It includes birds (sparrows, starlings, pigeons), rodents (rats and mice), and insects (cockroaches, bedbugs, moths). Many animals associated with humans feed on garbage in garbage dumps (jackdaws, sparrows). These are the city nurses. The decomposition of organic waste is accelerated by fly larvae and other animals and microorganisms.

The main feature of the ecosystems of modern cities is that the ecological balance is disturbed in them. All processes of regulating the flow of matter and energy a person has to take over. A person must regulate both the consumption of energy and resources by the city - raw materials for industry and food for people, and the amount of toxic waste entering the atmosphere, water and soil as a result of industry and transport. Finally, it also determines the size of these ecosystems, which in developed countries, and in recent years in Russia, are rapidly “spreading” due to suburban cottage construction. Low-rise areas reduce the area of ​​forests and agricultural land, their "spreading" requires the construction of new highways, which reduces the proportion of ecosystems capable of producing food and cycling oxygen.

Industrial pollution of the environment.

In urban ecosystems, industrial pollution is the most dangerous for nature.

Chemical pollution of the atmosphere. This factor is one of the most dangerous for human life. The most common contaminants

Sulfur dioxide, nitrogen oxides, carbon monoxide, chlorine, etc. In some cases, two or relatively several relatively harmless substances released into the atmosphere can form toxic compounds under the influence of sunlight. Ecologists number about 2,000 air pollutants.

The main sources of pollution are thermal power plants. Boiler houses, oil refineries and vehicles also heavily pollute the atmosphere.

Chemical pollution of water bodies. Enterprises dump oil products, nitrogen compounds, phenol and many other industrial wastes into water bodies. During oil production, water bodies are polluted with saline species, oil and oil products are also spilled during transportation. In Russia, the lakes of the North of Western Siberia suffer the most from oil pollution. In recent years, the danger to aquatic ecosystems of domestic wastewater from urban sewers has increased. In these effluents, the concentration of detergents has increased, which microorganisms decompose with difficulty.

As long as the amount of pollutants emitted into the atmosphere or discharged into rivers is small, ecosystems themselves are able to cope with them. With moderate pollution, the water in the river becomes almost clean after 3-10 km from the source of pollution. If there are too many pollutants, ecosystems cannot cope with them and irreversible consequences begin.

The water becomes undrinkable and dangerous to humans. Polluted water is not suitable for many industries.

Pollution of the soil surface with solid waste. City dumps of industrial and household waste occupy large areas. Garbage may contain toxic substances such as mercury or other heavy metals, chemical compounds that dissolve in rain and snow water and then enter water bodies and groundwater. Can get into garbage and devices containing radioactive substances.

The surface of the soil can be polluted by ash deposited from the smoke of coal-fired thermal power plants, cement factories, refractory bricks, etc. To prevent this contamination, special dust collectors are installed on the pipes.

Chemical pollution of groundwater. Groundwater currents transport industrial pollution over long distances, and it is not always possible to determine their source. The cause of pollution may be the washing out of toxic substances by rain and snow water from industrial landfills. Groundwater pollution also occurs during oil production using modern methods, when, in order to increase the return of oil reservoirs, salt water is re-injected into the wells, which has risen to the surface along with the oil during its pumping.

Salt water enters the aquifers, the water in the wells becomes bitter and undrinkable.

Noise pollution. The source of noise pollution can be an industrial enterprise or transport. Especially heavy dump trucks and trams produce a lot of noise. Noise affects the human nervous system, and therefore noise protection measures are taken in cities and enterprises.

Railway and tram lines and roads, along which freight transport passes, need to be moved from the central parts of cities to sparsely populated areas and create green spaces around them that absorb noise well.

Planes should not fly over cities.

Noise is measured in decibels. Clock ticking - 10 dB, whisper - 25, noise from a busy highway - 80, aircraft takeoff noise - 130 dB. The pain threshold of noise is 140 dB. On the territory of residential development during the day, the noise should not exceed 50-66 dB.

Also, pollutants include: contamination of the soil surface with overburden and ash dumps, biological pollution, thermal pollution, radiation pollution, electromagnetic pollution.

Air pollution. If air pollution over the ocean is taken as a unit, then over villages it is 10 times higher, over small towns - 35 times, and over large cities - 150 times. The thickness of the layer of polluted air over the city is 1.5 - 2 km.

The most dangerous pollutants are benz-a-pyrene, nitrogen dioxide, formaldehyde, and dust. In the European part of Russia and the Urals, on average, during the year per 1 sq. km. km, more than 450 kg of atmospheric pollutants fell.

Compared to 1980, the amount of sulfur dioxide emissions increased by 1.5 times; 19 million tons of atmospheric pollutants were thrown into the atmosphere by road transport.

Wastewater discharge into rivers amounted to 68.2 cubic meters. km with a post-consumption of 105.8 cubic meters. km. Water consumption by industry is 46%. The share of untreated wastewater has been decreasing since 1989 and amounts to 28%.

Due to the predominance of westerly winds, Russia receives 8-10 times more air pollutants from its western neighbors than it sends to them.

Acid rains have negatively affected half of the forests of Europe, and the process of drying out of forests has begun in Russia as well. In Scandinavia, 20,000 lakes have already died due to acid rain coming from the UK and Germany. Under the influence of acid rain, architectural monuments are dying.

Harmful substances coming out of a chimney 100 m high are dispersed within a radius of 20 km, 250 m high - up to 75 km. The champion pipe was built at a copper-nickel plant in Sudbury (Canada) and has a height of more than 400 m.

Ozone-depleting chlorofluorocarbons (CFCs) enter the atmosphere from cooling system gases (48% in the US and 20% in other countries), aerosol cans (2% in the US and banned a few years ago; 35% in other countries), solvents used in dry cleaners (20%) and in the production of foams, including styroform (25-

The main source of freons that destroy the ozone layer are industrial refrigerators - refrigerators. In an ordinary household refrigerator, 350 g of freon, and in industrial refrigerators - tens of kilograms. Refrigeration only in

Moscow annually uses 120 tons of freon. A significant part of it, due to the imperfection of the equipment, ends up in the atmosphere.

Pollution of freshwater ecosystems. In 1989, 1.8 tons of phenols, 69.7 tons of sulfates, 116.7 tons of synthetic surface-active substances (surfactants) were discharged into Lake Ladoga - a reservoir of drinking water for the six millionth St. Petersburg - in 1989.

Pollutes aquatic ecosystems and river transport. On Lake Baikal, for example, 400 ships of various sizes float, they dump about 8 tons of oil products into the water per year.

At most Russian enterprises, toxic production wastes are either dumped into water bodies, poisoning them, or accumulated without processing, often in huge quantities. These accumulations of deadly waste can be called "environmental mines"; when dams break, they can end up in water bodies. An example of such an "environmental mine" is the Cherepovets chemical plant "Ammophos". Its septic tank covers an area of ​​200 hectares and contains 15 million tons of waste. The dam that encloses the sump is raised annually by

4 m. Unfortunately, the "Cherepovets mine" is not the only one.

In developing countries, 9 million people die every year. By the year 2000, more than 1 billion people will lack drinking water.

Pollution of marine ecosystems. About 20 billion tons of garbage have been dumped into the World Ocean - from domestic sewage to radioactive waste. Every year for every 1 sq. km of the water surface add another 17 tons of garbage.

More than 10 million tons of oil is poured into the ocean every year, which forms a film covering 10-15% of its surface; and 5 g of petroleum products is enough to tighten the film 50 square meters. m of water surface. This film not only reduces the evaporation and absorption of carbon dioxide, but also causes oxygen starvation and the death of eggs and young fish.

Radiation pollution. It is assumed that by the year 2000 the world will have accumulated

1 million cubic meters m of high-level radioactive waste.

The natural radioactive background affects every person, even those who do not come into contact with nuclear power plants or nuclear weapons. We all receive a certain dose of radiation in our lifetime, 73% of which comes from the radiation of natural bodies (for example, granite in monuments, house cladding, etc.), 14% from medical procedures (primarily from visiting an X-ray room) and 14% from cosmic rays. Over a lifetime (70 years), a person can, without much risk, gain radiation of 35 rem (7 rem from natural sources, 3 rem from space sources and x-ray machines). In the zone of the Chernobyl nuclear power plant in the most polluted areas, you can get up to 1 rem per hour. The radiation power on the roof during the period of extinguishing a fire at a nuclear power plant reached 30,000 roentgens per hour, and therefore, without radiation protection (a lead suit), a lethal dose of radiation could be obtained in 1 minute.

The hourly dose of radiation, lethal to 50% of organisms, is 400 rem for humans, 1000-2000 rem for fish and birds, from 1000 to 150,000 for plants, and 100,000 rem for insects. Thus, the strongest pollution is not a hindrance to the mass reproduction of insects. Of the plants, trees are the least resistant to radiation and grasses are the most resistant.

Pollution with household waste. The amount of accumulated garbage is constantly growing. Now it is from 150 to 600 kg per year for every city dweller. Most of the garbage is produced in the USA (520 kg per year per inhabitant), in Norway, Spain, Sweden, the Netherlands - 200-300 kg, and in Moscow - 300-320 kg.

In order for paper to decompose in the natural environment, it takes from 2 to 10 years, a tin can - more than 90 years, a cigarette filter - 100 years, a plastic bag - more than 200 years, plastic - 500 years, glass - more than 1000 years.

Ways to reduce harm from chemical pollution

The most common pollution - chemical. There are three main ways to reduce the harm from them.

Dilution. Even treated effluents must be diluted 10 times (and untreated - 100-200 times). High chimneys are built at enterprises so that the emitted gases and dust are dispersed evenly. Dilution is an ineffective way to reduce the harm from pollution, acceptable only as a temporary measure.

Cleaning. This is the main way to reduce emissions of harmful substances into the environment in Russia today. However, as a result of treatment, a lot of concentrated liquid and solid wastes are generated, which also have to be stored.

Replacing old technologies with new low-waste technologies. Due to deeper processing, it is possible to reduce the amount of harmful emissions by dozens of times. Waste from one industry becomes raw material for another.

Figurative names for these three ways to reduce environmental pollution were given by German ecologists: “lengthen the pipe” (dilution by dispersion), “plug the pipe” (cleaning) and “tie the pipe in a knot” (low-waste technologies). The Germans restored the ecosystem of the Rhine, which for many years was a sewer where the waste of industrial giants was dumped. This was done only in the 80s, when, finally, "the pipe was tied in a knot."

The level of environmental pollution in Russia is still very high, and an ecologically unfavorable situation dangerous for the health of the population has developed in almost 100 cities of the country.

Some improvement in the environmental situation in Russia has been achieved due to improved operation of treatment facilities and a drop in production.

Further reduction of emissions of toxic substances into the environment can be achieved if less hazardous low-waste technologies are introduced. However, in order to “tie the pipe in a knot”, it is necessary to upgrade equipment at enterprises, which requires very large investments and therefore will be carried out gradually.

Cities and industrial facilities (oil fields, quarries for the development of coal and ore, chemical and metallurgical plants) operate on energy that comes from other industrial ecosystems (energy complex), and their products are not plant and animal biomass, but steel, iron and aluminum, various machines and devices, building materials, plastics and much more that is not found in nature.

The problems of urban ecology are, first of all, the problems of reducing emissions of various pollutants into the environment and protecting water, atmosphere, and soil from cities. They are solved by creating new low-waste technologies and production processes and efficient treatment facilities.

Plants play an important role in mitigating the impact of urban environmental factors on humans. Green spaces improve the microclimate, trap dust and gases, and have a beneficial effect on the mental state of citizens.

Literature:

Mirkin B.M., Naumova L.G. Ecology of Russia. A textbook from the federal set for grades 9-11 of a comprehensive school. Ed. 2nd, revised.

And extra. - M.: AO MDS, 1996. - 272 with ill.