Environmental factors non-living. Classification of environmental factors

State educational institution

Higher professional education.

"ST. PETERSBURG STATE UNIVERSITY

SERVICE AND ECONOMY"

Discipline: Ecology

Institute (Faculty): (IREU) “Institute of Regional Economics and Management”

Specialty: 080507 “Management of Organizations”

On the topic: Environmental factors and their classification.

Performed:

Valkova Violetta Sergeevna

1st year student

Part-time study

Supervisor:

Ovchinnikova Raisa Andreevna

2008 – 2009

INTRODUCTION ………………………………………………………… …………………………………..3

ENVIRONMENTAL FACTORS. ENVIRONMENTAL CONDITIONS……………………………………...3

Abiotic

Biotic

Anthropogenic

BIOTIC RELATIONSHIPS OF ORGANISMS ……………… ……………….6

GENERAL REGULARITIES OF THE INFLUENCE OF ECOLOGICAL ENVIRONMENTAL FACTORS ON ORGANISMS…………………………………………………………………… …………………………….7

CONCLUSION ………………………………………………………………………………… ………………………9

LIST OF REFERENCES ………… …………………………………………………………..10

INTRODUCTION

Let us imagine one species of plants or animals and in it one individual, mentally isolating her from the rest of the living world. This individual, while under the influence environmental factors will be influenced by them. The main one will be factors determined by climate. Everyone is well aware, for example, that representatives of one or another species of plants and animals are not found everywhere. Some plants live only along the banks of water bodies, others - under the forest canopy. You cannot meet a lion in the Arctic, nor a polar bear in the Gobi Desert. We recognize that climatic factors (temperature, humidity, light, etc.) are of greatest importance in the distribution of species. For terrestrial animals, especially soil dwellers, and plants, the physical and chemical properties of the soil play an important role. For aquatic organisms, the properties of water as the only habitat are of particular importance. The study of the effects of various natural factors on individual organisms is the first and simplest division of ecology.

ENVIRONMENTAL FACTORS. ENVIRONMENTAL CONDITIONS

Diversity of environmental factors. Environmental factors are any external factors that have a direct or indirect effect on the number (abundance) and geographic distribution of animals and plants.

Environmental factors are very diverse both in nature and in their impact on living organisms. Conventionally, all environmental factors are divided into three large groups - abiotic, biotic and anthropogenic.

Abiotic factors – these are factors of inanimate nature, primarily climatic (sunlight, temperature, air humidity), and local (relief, soil properties, salinity, currents, wind, radiation, etc.). These factors can affect the body directly(directly) as light and heat, or indirectly, such as, for example, the terrain, which determines the action of direct factors (lighting, moisture, wind, etc.).

Anthropogenic factors – These are those forms of human activity that, by affecting the environment, change the conditions of living organisms or directly affect certain species of plants and animals. One of the most important anthropogenic factors is pollution.

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. Let us consider the effect of these factors in more detail.

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 areas 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 at different times of the year. 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.

Humidity. For most of its history, wildlife was represented by exclusively aquatic forms of organisms. Having conquered land, they nevertheless 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 mites, 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, there has been a distinction 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. Everyone knows how nocturnal insects flock to the light or how cockroaches scatter in search of shelter if only a light is turned on in a dark room.

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 sink 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, such as wind, atmospheric pressure, altitude. Wind has an indirect effect: by increasing evaporation, it increases dryness. Strong winds contribute to cooling. This action is important in cold places, high mountains or polar regions.

Anthropogenic factors. Pollutants. Anthropogenic factors are very diverse in their composition. Man influences living nature by laying roads, building cities, conducting agriculture, blocking rivers, etc. Modern human activity is increasingly manifested in environmental pollution with by-products, often toxic. Sulfur dioxide flying from the pipes of factories and thermal power plants, metal compounds (copper, zinc, lead) discharged near mines or formed in the exhaust gases of cars, residues of petroleum products discharged into water bodies when washing oil tankers - these are just some of the pollutants that limit the spread organisms (especially plants).

In industrial areas, the concept of pollutants sometimes reaches threshold levels, i.e. lethal for many organisms, values. However, no matter what, there will almost always be at least a few individuals of several species that can survive in such conditions. The reason is that even in natural populations, resistant individuals are rarely found. As pollution levels increase, resistant individuals may be the only survivors. Moreover, they can become the founders of a stable population that has inherited immunity to this type of pollution. For this reason, pollution gives us the opportunity to, as it were, observe evolution in action. Of course, not every population is endowed with the ability to resist pollution, even if only in the form of single individuals.

Thus, the effect of any pollutant is twofold. If this substance has appeared recently or is contained in very high concentrations, then each species previously found in the contaminated area is usually represented by only a few specimens - precisely those that, due to natural variability, had initial stability or their closest flows.

Subsequently, the polluted area turns out to be populated much more densely, but as a rule, with a much smaller number of species than if there was no pollution. Such newly emerged communities with a depleted species composition have already become an integral part of the human environment.

BIOTIC RELATIONSHIPS OF ORGANISMS

Two types of any organisms living in the same territory and in contact with each other enter into different relationships with each other. The position of the species in different forms of relationships is indicated by conventional signs. A minus sign (–) indicates an adverse effect (individuals of the species are oppressed or harmed). A plus sign (+) indicates a beneficial effect (individuals of the species benefit). The zero sign (0) indicates that the relationship is indifferent (no influence).

Thus, all biotic connections can be divided into 6 groups: none of the populations influences the other (00); mutually beneficial useful connections (+ +); relationships harmful to both species (– –); one of the species benefits, the other experiences oppression (+ –); one species benefits, the other does not experience harm (+ 0); one species is oppressed, the other does not benefit (– 0).

For one of the species living together, the influence of the other is negative (he experiences oppression), while the oppressor receives neither harm nor benefit - this amensalism(–0). An example of amensalism is light-loving herbs growing under a spruce tree, suffering from strong shading, while the tree itself is indifferent to this.

The form of relationship in which one species receives some advantage without causing any harm or benefit to the other is called commensalism(+ 0). For example, large mammals (dogs, deer) serve as carriers of fruits and seeds with hooks (like burdock), receiving neither harm nor benefit from this.

Commensalism is the unilateral use of one species by another without causing damage to it. The manifestations of commensalism are varied, so a number of variants are distinguished.

“Freeloading” is the consumption of the owner’s leftover food.

“Companionship” is the consumption of different substances or parts of the same food.

“Housing” is the use by one species of another (their bodies, their homes (as a shelter or home.

In nature, mutually beneficial relationships between species are often found, with some organisms receiving mutual benefit from these relationships. This group of mutually beneficial biological connections includes diverse symbiotic relationships between organisms. An example of symbiosis is lichens, which are a close, mutually beneficial cohabitation of fungi and algae. A well-known example of symbiosis is the cohabitation of green plants (primarily trees) and mushrooms.

One type of mutually beneficial relationship is protocooperation(primary cooperation) (+ +). At the same time, coexistence, although not obligatory, is beneficial for both species, but is not an indispensable condition for survival. An example of protocooperation is the dispersal of seeds of certain forest plants by ants and the pollination of various meadow plants by bees.

If two or more species have similar ecological requirements and live together, a negative type of relationship may arise between them, which is called competition(rivalry, competition) (– –). For example, all plants compete for light, moisture, soil nutrients and, therefore, to expand their territory. Animals fight for food resources, shelters and also for territory.

Predation(+ –) is a type of interaction between organisms in which representatives of one species kill and eat representatives of another.

These are the main types of biotic interactions in nature. It should be remembered that the type of relationship of a particular pair of species may change depending on external conditions or the life stage of the interacting organisms. Moreover, in nature, it is not just a couple of species that are simultaneously involved in biotic relationships, but a much larger number of them.

GENERAL REGULARITIES OF THE INFLUENCE OF ECOLOGICAL ENVIRONMENTAL FACTORS ON ORGANISMS

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.

This pattern can be transferred to any other factor that determines the speed of certain life processes (humidity, wind strength, current speed, etc.).

If you draw a curve on a graph that characterizes the intensity of a particular process (breathing, movement, nutrition, etc.) depending on one of the environmental factors (of course, provided that this factor influences the main life processes), then this curve will almost always be bell-shaped.

These curves are called curves tolerance(from Greek tolerance- patience, stability). The position of the apex of the curve indicates the conditions that are optimal for a given process.

Some individuals and species are characterized by curves with very sharp peaks. This means that the range of conditions under which the body's activity reaches its maximum is very narrow. Flat curves correspond to a wide range of tolerance.

Organisms with wide margins of resistance certainly have a chance of becoming more widespread. However, wide limits of endurance for one factor do not mean wide limits for all factors. The plant may be tolerant of large temperature fluctuations, but have narrow ranges of water tolerance. An animal like trout can be very temperature sensitive but eat a wide variety of foods.

Sometimes during the life of an individual, its tolerance may change (the position of the curve will change accordingly), if the individual finds itself in different external conditions. Finding yourself in such conditions, after a while the body gets used to it and adapts to them. The consequence of this is a change in the physiological optimum, or a shift in the dome of the tolerance curve. This phenomenon is called adaptation, or acclimatization.

In species with a wide geographical distribution, the inhabitants of geographical or climatic zones often turn out to be best adapted precisely to those conditions that are characteristic of a given area. This is due to the ability of some organisms to form local forms, or ecotypes, characterized by different limits of resistance to temperature, light or other factors.

Let us consider as an example the ecotypes of one of the jellyfish species. Jellyfish move through water using rhythmic contractions of muscles that push water out of the central cavity of the body, similar to the movement of a rocket. The optimal frequency of such pulsation is 15-20 contractions per minute. Individuals living in the seas of northern latitudes move at the same speed as jellyfish of the same species in the seas of southern latitudes, although the water temperature in the north can be 20 °C lower. Consequently, both forms of organisms of the same species were able to best adapt to local conditions.

Law of the minimum. The intensity of certain biological processes is often sensitive to two or more environmental factors. In this case, the factor that is present in the minimum quantity, from the point of view of the body’s needs, will be of decisive importance. This rule was formulated by the founder of the science of mineral fertilizers Justus Liebig(1803-1873) and received the name Law of the minimum. Yu. Liebig discovered that plant yield can be limited by any of the basic nutrients, if only this element is in short supply.

It is known that different environmental factors can interact, that is, a deficiency of one substance can lead to a deficiency of other substances. Therefore, in general, the law of the minimum can be formulated as follows: the successful survival of living organisms depends on a set of conditions; a limiting, or limiting, factor is any state of the environment that approaches or goes beyond the limit of stability for organisms of a given species.

The provision on limiting factors greatly facilitates the study of complex situations. Despite the complexity of the relationships between organisms and their environment, not all factors have the same ecological significance. For example, oxygen is a factor of physiological necessity for all animals, but from an ecological point of view it becomes limiting only in certain habitats. If fish die in a river, the oxygen concentration in the water must first be measured, since it is highly variable, oxygen reserves are easily depleted and there is often not enough oxygen. If the death of birds is observed in nature, it is necessary to look for another reason, since the oxygen content in the air is relatively constant and sufficient from the point of view of the requirements of terrestrial organisms.

CONCLUSION

Ecology is a vitally important science for humans that studies their immediate natural environment. Man, observing nature and its inherent harmony, involuntarily sought to bring this harmony into his life. This desire became especially acute only relatively recently, after the consequences of unreasonable economic activities leading to the destruction of the natural environment became very noticeable. And this ultimately had an adverse effect on the person himself.

It should be remembered that ecology is a fundamental scientific discipline, the ideas of which are very important. And if we recognize the importance of this science, we need to learn to correctly use its laws, concepts, and terms. After all, they help people determine their place in their environment and use natural resources correctly and rationally. It has been proven that human use of natural resources with complete ignorance of the laws of nature often leads to serious, irreparable consequences.

Every person on the planet should know the basics of ecology as a science about our common home – the Earth. Knowledge of the basics of ecology will help both society and the individual build their lives wisely; they will help everyone feel like a part of the great Nature, achieve harmony and comfort where previously there was an unreasonable struggle with natural forces.

LIST OF REFERENCES USED Ecological environmental factors (Biotic factors; Biotic environmental factors; Biotic factors; ....5 Question No. 67 Natural resources, their classification. Resource cycle NATURAL RESOURCES (natural...

These are any environmental factors to which the body responds with adaptive reactions.

Environment is one of the main ecological concepts, which means a complex of environmental conditions that affect the life of organisms. In a broad sense, the environment is understood as the totality of material bodies, phenomena and energy that affect the body. It is also possible to have a more specific, spatial understanding of the environment as the immediate surroundings of an organism - its habitat. The habitat is everything that an organism lives among; it is a part of nature that surrounds living organisms and has a direct or indirect influence on them. Those. elements of the environment that are not indifferent to a given organism or species and in one way or another influence it are factors in relation to it.

The components of the environment are diverse and changeable, therefore living organisms constantly adapt and regulate their life activities in accordance with the occurring variations in the parameters of the external environment. Such adaptations of organisms are called adaptation and allow them to survive and reproduce.

All environmental factors are divided into

• Abiotic factors are factors of inanimate nature that directly or indirectly affect the body - light, temperature, humidity, chemical composition of the air, water and soil environment, etc. (i.e., properties of the environment, the occurrence and impact of which does not directly depend on the activity of living organisms) .
• Biotic factors are all forms of influence on the body from surrounding living beings (microorganisms, the influence of animals on plants and vice versa).
• Anthropogenic factors are various forms of activity of human society that lead to changes in nature as the habitat of other species or directly affect their lives.

Environmental factors affect living organisms

• as irritants causing adaptive changes in physiological and biochemical functions;
• as limitations that make it impossible to exist in given conditions;
• as modifiers that cause structural and functional changes in organisms, and as signals indicating changes in other environmental factors.

In this case, it is possible to establish the general nature of the impact of environmental factors on a living organism.

Any organism has a specific set of adaptations to environmental factors and exists safely only within certain limits of their variability. The most favorable level of the factor for life is called optimal.

At small values ​​or with excessive exposure to the factor, the vital activity of organisms drops sharply (noticeably inhibited). The range of action of an environmental factor (the area of ​​tolerance) is limited by the minimum and maximum points corresponding to the extreme values ​​of this factor at which the existence of the organism is possible.

The upper level of the factor, beyond which the vital activity of organisms becomes impossible, is called the maximum, and the lower level is called the minimum (Fig.). Naturally, each organism is characterized by its own maximums, optimums and minimums of environmental factors. For example, a housefly can withstand temperature fluctuations from 7 to 50 ° C, but the human roundworm lives only at human body temperature.

The optimum, minimum and maximum points make up three cardinal points that determine the body’s ability to react to a given factor. The extreme points of the curve, expressing the state of oppression with a deficiency or excess of a factor, are called pessimum areas; they correspond to the pessimal values ​​of the factor. Near the critical points there are sublethal values ​​of the factor, and outside the tolerance zone there are lethal zones of the factor.

Environmental conditions under which any factor or their combination goes beyond the comfort zone and has a depressing effect are often called extreme, borderline (extreme, difficult) in ecology. They characterize not only environmental situations (temperature, salinity), but also habitats where conditions are close to the limits of existence for plants and animals.

Any living organism is simultaneously affected by a complex of factors, but only one of them is limiting. A factor that sets the framework for the existence of an organism, species or community is called limiting (limiting). For example, the distribution of many animals and plants to the north is limited by a lack of heat, while in the south the limiting factor for the same species may be a lack of moisture or necessary food. However, the limits of the body's endurance in relation to the limiting factor depend on the level of other factors.

The life of some organisms requires conditions limited by narrow limits, that is, the optimum range is not constant for the species. The optimum effect of the factor is different in different species. The span of the curve, i.e., the distance between the threshold points, shows the area of ​​influence of the environmental factor on the body (Fig. 104). In conditions close to the threshold action of the factor, organisms feel depressed; they may exist, but do not reach full development. The plants usually do not bear fruit. In animals, on the contrary, puberty accelerates.

The magnitude of the range of action of the factor and especially the optimum zone makes it possible to judge the endurance of organisms in relation to a given element of the environment and indicates their ecological amplitude. In this regard, organisms that can live in fairly diverse environmental conditions are called zvrybionts (from the Greek “euros” - wide). For example, a brown bear lives in cold and warm climates, in dry and humid areas, and eats a variety of plant and animal foods.

In relation to private environmental factors, a term beginning with the same prefix is ​​used. For example, animals that can live in a wide range of temperatures are called eurythermal, while organisms that can live only in narrow temperature ranges are called stenothermic. By the same principle, an organism can be euryhydrid or stenohydrid, depending on its response to fluctuations in humidity; euryhaline or stenohaline - depending on the ability to tolerate different salinity values, etc.

There are also the concepts of ecological valence, which represents the ability of an organism to inhabit a variety of environments, and ecological amplitude, which reflects the width of the range of a factor or the width of the optimum zone.

The quantitative patterns of the reaction of organisms to the action of an environmental factor differ in accordance with their living conditions. Stenobionticity or eurybionticity does not characterize the specificity of a species in relation to any environmental factor. For example, some animals are confined to a narrow range of temperatures (i.e., stenothermic) and at the same time can exist in a wide range of environmental salinity (euryhaline).

Environmental factors influence a living organism simultaneously and jointly, and the action of one of them depends to a certain extent on the quantitative expression of other factors - light, humidity, temperature, surrounding organisms, etc. This pattern is called the interaction of factors. Sometimes the deficiency of one factor is partially compensated by the increased activity of another; partial substitutability of the effects of environmental factors appears. At the same time, none of the factors necessary for the body can be completely replaced by another. Phototrophic plants cannot grow without light under the most optimal temperature or nutrition conditions. Therefore, if the value of at least one of the necessary factors goes beyond the tolerance range (below the minimum or above the maximum), then the existence of the organism becomes impossible.

Environmental factors that have a pessimal value in specific conditions, i.e., those that are furthest from the optimum, especially complicate the possibility of the species existing in these conditions, despite the optimal combination of other conditions. This dependence is called the law of limiting factors. Such factors deviating from the optimum acquire paramount importance in the life of a species or individual individuals, determining their geographic range.

Identification of limiting factors is very important in agricultural practice to establish ecological valency, especially in the most vulnerable (critical) periods of the ontogenesis of animals and plants.

LECTURE No. 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

An environmental factor is any element of the environment that can directly or indirectly influence 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 a corresponding environmental condition and its resource (reserve in the environment).

Ecological 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 distinctive features. Thus, factors are identified 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, but epidemics (mass diseases) caused by pathogenic microorganisms depend on their number in a given territory. There are known classifications in which all anthropogenic factors are classified as biotic.

2. Abiotic factors

In the abiotic part of the environment (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, cosmic 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, there will be frostbite. Other factors can also influence the effect of temperature: in water - current, on land - wind and humidity, etc.

Chemical factors- these are those that originate from the chemical composition of the environment. For example, the salinity of 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 oxygen levels.

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

2.1. Ecological role of main abiotic factors

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

About 99% of all solar radiation energy consists of rays with a wavelength k = nm, including 48% in the visible part of the spectrum (k = nm), 45% in the near infrared (k = nm) and about 7% in the ultraviolet (To< 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 > 320 nm in small doses are necessary for animals and humans, since under their influence 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 sunlight passes through atmospheric air, it is reflected, scattered and absorbed. Clean snow reflects approximately 80-95% of sunlight, polluted snow - 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, light and dark periods periodically alternate. Flowering, seed germination in plants, migration, hibernation, animal reproduction and much more in nature are associated with the length of the photoperiod (day length). The need for light for plants determines their rapid growth in height and 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 solar energy falling on the Earth is used for photosynthesis);

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

3. Photoperiodism (provides synchronicity of life processes in living organisms with 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, temperature conditions. In this regard, special adaptive reactions have been developed in the form of tiering, mosaic leaves, phenological differences, etc. Based on their demands on lighting conditions, plants are divided into light or light-loving (sunflower, plantain, tomato, acacia, melon), shady or non-light-loving (forest herbs, mosses) and shade-tolerant (sorrel, heather, rhubarb, raspberries, blackberries).

Plants form the conditions for the existence of other species of living beings. This is why their reaction to lighting conditions is so important. Environmental pollution leads to changes in illumination: a decrease in the level of solar insolation, a decrease in the amount of photosynthetically active radiation (PAR is the part of solar radiation with a wavelength from 380 to 710 nm), and 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 primarily related to solar radiation, but in some cases is determined by energy from 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, enzymes are denatured. 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 (and therefore the metabolic rate) doubles with every 10°C increase in temperature.

A significant part of organisms are able to control (maintain) body temperature, primarily in 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 an unstable temperature, depending on the ambient temperature.

Poikilothermic organisms in the cold season or day reduce the level of life processes up to anabiosis. This primarily concerns plants, microorganisms, fungi and poikilothermic (cold-blooded) animals. Only homeothermic (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, gophers).

Thermoregulation of homeothermic animals is ensured by a special type of metabolism that occurs with the release of heat in the animal’s body, 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– ability to withstand low positive temperatures for a long time (from O°C to +5°C);

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

frost resistance– ability to withstand negative temperatures for a long time;

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

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

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

In an aquatic environment, due to the high heat capacity of water, temperature changes are less dramatic and conditions are more stable than on land. It is known that in regions where the temperature varies greatly throughout the day, as well as between 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. The effects of extreme temperatures (low and high) are amplified by strong winds.

The change in temperature as one rises in the air or immerses in an aquatic environment is called temperature stratification. Typically, in both cases there is a continuous decrease in temperature with a certain gradient. However, there are other options. Thus, in summer, surface waters heat up more than deep waters. Due to a significant decrease in the density of water as it heats up, its circulation begins in the heated surface layer without mixing with the denser, cold 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 water, as well as the transfer and dispersion of incoming impurities.

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

Some relief features contribute to inversion, for example, pits and valleys. It occurs when there are substances at a certain altitude, for example aerosols, heated directly by direct solar radiation, which causes more intense heating of the upper air layers.

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

Precipitation, humidity. Water is essential for life on Earth; in ecological terms, it is unique. Under almost identical geographical conditions, both a hot desert and a tropical forest exist on Earth. 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 high layers of the atmosphere. Dew and fog form in the ground layer of air, and at low temperatures crystallization of moisture is observed - frost falls.

One of the main physiological functions of any organism is to maintain a sufficient level of water in the body. In the process of evolution, organisms have developed various adaptations for obtaining and economically using water, as well as for surviving dry periods. Some desert animals obtain water from food, others through the oxidation of timely stored fats (for example, a camel, which is capable of obtaining 107 g of metabolic water from 100 g of fat through biological oxidation); At the same time, they have minimal water permeability of the outer integument of the body, and aridity is characterized by falling into a state of rest with a minimum metabolic rate.

Land plants obtain water mainly from the soil. Low precipitation, rapid drainage, intense evaporation, or a combination of these factors lead to drying out, 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 through transpiration]. In turn, evaporation processes directly depend on the relative humidity of the atmospheric air. When humidity is close to 100%, evaporation practically stops, and if the temperature drops further, the reverse process begins - condensation (fog forms, dew and frost fall out).

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

Air saturation with water vapor rarely reaches its maximum value. Humidity deficit is 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 it is, 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 whose entire life cycle takes place in water;

hygrophytes– plants of wet habitats (marsh marigold, European swimmer, broadleaf cattail);

hygrophiles– animals living in very damp parts of ecosystems (molluscs, amphibians, mosquitoes, woodlice);

mesophytes– plants of moderately humid habitats;

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

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

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

sclerophytes– plants of very arid areas that can withstand severe dehydration (common camel thorn, saxaul, saksagyz);

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

Plant moisture consumption can be characterized by the following indicators:

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

moisture resistance– ability to tolerate waterlogging;

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

total water consumption coefficient- 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 and pollution of surface waters are dangerous, and in some cases detrimental to cenoses. Changes in the water cycle in the biosphere can lead to unpredictable consequences for all living organisms.

Mobility of the environment. The causes of the movement of air masses (wind) are primarily unequal heating of the earth's surface, causing pressure changes, 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 point 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.

Wind accelerates transpiration (evaporation of moisture from above-ground parts of plants), which especially worsens living conditions 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 help maintain 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 places, and 3 m/s near the Gulf Stream.

Pressure. Normal atmospheric pressure is considered to be an absolute pressure at the surface of the World Ocean 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 seasonal and daily fluctuations are observed at the same points. As altitude increases relative to ocean level, pressure decreases, partial pressure of oxygen decreases, and transpiration in plants increases.

Periodically, areas of low pressure form 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, weak winds and, in some cases, temperature inversions. During anticyclones, sometimes unfavorable meteorological conditions arise that contribute to the accumulation of pollutants in the surface layer of the atmosphere.

There are also marine and continental atmospheric pressures.

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 body, 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 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 that once arose during the formation of the Earth's substance. Due to the long half-life, the nuclei of many primordial radioactive elements have been preserved in the bowels of the Earth to the present day. The most important of them are potassium-40, thorium-232, uranium-235 and uranium-238. Under the influence of cosmic radiation, new nuclei of radioactive atoms are constantly being formed in the atmosphere, the main ones being carbon-14 and tritium.

The radiation background of a 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 geographic location. Man, as an inhabitant of the natural environment, receives the bulk of radiation from natural sources of radiation, and it is impossible to avoid this. All life on Earth is exposed to radiation from Space. Mountain landscapes, due to their significant altitude above sea level, are characterized by an increased contribution of cosmic radiation. Glaciers, acting as an absorbing screen, trap radiation from underlying bedrock within their mass. Differences in the content of radioactive aerosols over the sea and land were discovered. The total radioactivity of sea air is hundreds and thousands of times less than that of continental air.

There are areas on Earth where the exposure dose rate is tens of 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 areas where granite rocks emerge.

Biological processes accompanying the formation of soils significantly influence the accumulation of radioactive substances in the latter. With a low content of humic substances, their activity is weak, while chernozems have always had 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 specific activity, soils can be roughly arranged in the following order: peat; chernozem; soils of the steppe zone and forest-steppe; soils developing on granites.

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

In many areas of the globe, the exposure dose rate caused by radiation from uranium and thorium reaches the level of radiation that existed on Earth in geologically foreseeable time, during 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 humans are particularly sensitive. Some substances are distributed evenly throughout the body, such as carbon-14 or tritium, while others accumulate in certain organs. Thus, radium-224, -226, lead-210, polonium-210 accumulate in bone tissue. The inert gas radon-220, which is sometimes released not only from deposits in the lithosphere, but also from minerals mined by humans and used as building materials, has a strong effect on the lungs. Radioactive substances can accumulate in water, soil, sediment, or air if their rate of release exceeds the rate of radioactive decay. In living organisms, the accumulation of radioactive substances occurs when they enter with food.

2.2. Topographical factors

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

Mountain ranges can act as climate barriers. Rising above the mountains, the air cools, which often causes precipitation and thereby reduces its absolute moisture content. Then reaching the other side of the mountain range, the dried air helps reduce the intensity of rain (snowfall), thereby creating 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(illumination) of the slope. In the Northern Hemisphere it is warmer on the southern slopes, and 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, with slopes greater 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 occurring in outer space. The Earth periodically collides with asteroids, approaches comets, and is hit by cosmic dust, meteorite substances, and various types of radiation from the Sun and stars. Solar activity changes cyclically (one of the cycles has a period of 11.4 years).

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

3. Biotic factors

All living things surrounding an organism in its habitat constitute the biotic environment or biota. Biotic factors- this is a set of influences of the life 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- relationships between representatives of different species.

Representatives of each species are able to exist in a biotic environment where connections with other organisms provide them with normal living conditions. The main form of manifestation of these connections is the food 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 connections, spatial relationships also arise between plant and animal organisms. As a result of the action of many factors, various species are united not in arbitrary combination, but only under the condition of adaptability to living together.

Biotic factors manifest themselves in biotic relationships.

The following forms of biotic relationships are distinguished.

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

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

Commensalism. Commensalism is an interaction between organisms when the life activity of one provides food (freeloading) or shelter (lodging) to another. Typical examples are hyenas picking up the remains of prey left uneaten 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 soils poor in nitrogen and enrich the soil with it.

Antibiosis. A form of relationship in which both partners or one of them experiences a negative influence 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 predator and prey that involves one organism being eaten by another. Predators are animals or plants that catch and eat animals as food. For example, lions eat herbivorous ungulates, birds eat insects, and large fish eat 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 seeks (and cannot) lead to the destruction of another. Moreover, the disappearance of any natural “enemy” (predator) from the habitat may 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 varying degrees.

Recently, increasing attention has been paid to anthropogenic factors– the totality of human impacts on the environment caused by 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 allocate to 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 by emissions into it mainly of CO, CO2, and other gases;

Littering of near-Earth space (ENS), the consequences of which have not yet been fully understood, except for the real danger to spacecraft, including communication satellites, earth surface locations and others, which 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”, reducing the protective capabilities of the atmosphere against the entry to the Earth’s surface of hard short-wave ultraviolet radiation dangerous for living organisms;

Chemical pollution of the atmosphere with substances that contribute to the formation of acid precipitation, photochemical smog and other compounds dangerous to biosphere objects, including humans and the artificial objects they create;

Ocean pollution and changes in the properties of ocean waters due to petroleum products, their saturation with carbon dioxide in the atmosphere, in turn polluted by motor vehicles and thermal power engineering, burial of highly toxic chemical and radioactive substances in ocean waters, the entry of pollutants with river runoff, disturbances in the water balance of coastal areas due to regulation rivers;

Depletion and pollution of all types of land sources and waters;

Radioactive contamination of individual areas and regions with a tendency to spread across the Earth’s surface;

Soil pollution due to contaminated precipitation (for example, acid rain), suboptimal use of pesticides and mineral fertilizers;

Changes in the geochemistry of landscapes due to thermal energy, redistribution of elements between the subsoil and the surface of the Earth as a result of mining and metallurgical processing (for example, the concentration of heavy metals) or the extraction to the surface of abnormal composition, highly mineralized groundwater and brines;

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

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

Continuing, and in some places increasing desertification of the planet, deepening of the desertification process;

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

As a result of all the above processes, the liberation of ecological niches and their filling with other species;

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

Deterioration of the living environment in overcrowded cities and megalopolises;

The depletion of many mineral deposits and the gradual transition from rich to increasingly poor ores;

Increasing social instability, as a consequence of the increasing differentiation of the rich and poor parts of the population of many countries, the increasing level of armament of their population, criminalization, and natural environmental disasters.

A decrease in the immune status and health status of the population of many countries of the world, including Russia, multiple repetitions of epidemics that are increasingly widespread and severe in their consequences.

This is not a complete range of problems, in solving each of which a specialist can find his place and business.

The most widespread and significant is chemical pollution of the environment with substances of a chemical nature that are 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 greatest danger among which are various diseases.

Tests questions And tasks

1. What are environmental factors?

2. Which environmental factors are considered abiotic and which are classified as biotic?

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

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

5. What factors should be considered first when creating ecosystem management projects. Why?

Environmental factors is a complex of environmental conditions affecting living organisms. Distinguish inanimate factors— abiotic (climatic, edaphic, orographic, hydrographic, chemical, pyrogenic), wildlife factors— biotic (phytogenic and zoogenic) and anthropogenic factors (impact of human activity). Limiting factors include any factors that limit the growth and development of organisms. The adaptation of an organism to its environment is called adaptation. The external appearance of an organism, reflecting its adaptability to environmental conditions, is called life form.

The concept of environmental environmental factors, their classification

Individual components of the environment that affect living organisms, to which they respond with adaptive reactions (adaptations), are called environmental factors, or environmental factors. In other words, the complex of environmental conditions affecting the life of organisms is called environmental environmental factors.

All environmental factors are divided into groups:

1. include components and phenomena of inanimate nature that directly or indirectly affect living organisms. Among the many abiotic factors, the main role is played by:

• climatic(solar radiation, light and light conditions, temperature, humidity, precipitation, wind, atmospheric pressure, etc.);
• edaphic(mechanical structure and chemical composition of the soil, moisture capacity, water, air and thermal conditions of the soil, acidity, humidity, gas composition, groundwater level, etc.);
• orographic(relief, slope exposure, slope steepness, elevation difference, altitude above sea level);
• hydrographic(water transparency, fluidity, flow, temperature, acidity, gas composition, content of mineral and organic substances, etc.);
• chemical(gas composition of the atmosphere, salt composition of water);
• pyrogenic(exposure to fire).

2. - the totality of relationships between living organisms, as well as their mutual influences on the habitat. The effect of biotic factors can be not only direct, but also indirect, expressed in the adjustment of abiotic factors (for example, changes in soil composition, microclimate under the forest canopy, etc.). Biotic factors include:

• phytogenic(the influence of plants on each other and on the environment);
• zoogenic(the influence of animals on each other and on the environment).

3. reflect the intense influence of humans (directly) or human activities (indirectly) on the environment and living organisms. Such factors include all forms of human activity and human society that lead to changes in nature as a habitat for other species and directly affect their lives. Every living organism is influenced by inanimate nature, organisms of other species, including humans, and in turn has an impact on each of these components.

The influence of anthropogenic factors in nature can be either conscious, accidental, or unconscious. Man, plowing virgin and fallow lands, creates agricultural land, breeds highly productive and disease-resistant forms, spreads some species and destroys others. These influences (conscious) are often negative, for example, the thoughtless resettlement of many animals, plants, microorganisms, the predatory destruction of a number of species, environmental pollution, etc.

Biotic environmental factors are manifested through the relationships of organisms belonging to the same community. In nature, many species are closely interrelated, and their relationships with each other as components of the environment can be extremely complex. As for the connections between the community and the surrounding inorganic environment, they are always two-way, reciprocal. Thus, the nature of the forest depends on the corresponding type of soil, but the soil itself is largely formed under the influence of the forest. Similarly, temperature, humidity and light in the forest are determined by vegetation, but the prevailing climatic conditions in turn affect the community of organisms living in the forest.

Impact of environmental factors on the body

The impact of the environment is perceived by organisms through environmental factors called environmental. It should be noted that the environmental factor is only a changing element of the environment, causing in organisms, when it changes again, adaptive ecological and physiological reactions that are hereditarily fixed in the process of evolution. They are divided into abiotic, biotic and anthropogenic (Fig. 1).

They name the entire set of factors in the inorganic environment that influence the life and distribution of animals and plants. Among them there are: physical, chemical and edaphic.

Physical factors - those whose source is a physical state or phenomenon (mechanical, wave, etc.). For example, temperature.

Chemical factors- those that originate from the chemical composition of the environment. For example, water salinity, oxygen content, etc.

Edaphic (or soil) factors are a set of chemical, physical and mechanical properties of soils and rocks that affect both the organisms for which they are a habitat and the root system of plants. For example, the influence of nutrients, humidity, soil structure, humus content, etc. on plant growth and development.

Rice. 1. Scheme of the impact of the habitat (environment) on the body

— human activity factors affecting the natural environment (hydrosphere, soil erosion, forest destruction, etc.).

Limiting (limiting) environmental factors These are factors that limit the development of organisms due to a lack or excess of nutrients compared to the need (optimal content).

Thus, when growing plants at different temperatures, the point at which maximum growth occurs will be optimum. The entire temperature range, from minimum to maximum, at which growth is still possible is called range of stability (endurance), or tolerance. The points limiting it, i.e. the maximum and minimum temperatures suitable for life are the limits of stability. Between the optimum zone and the limits of stability, as it approaches the latter, the plant experiences increasing stress, i.e. we're talking about about stress zones, or zones of oppression, within the stability range (Fig. 2). As you move further down and up the scale from the optimum, not only does stress intensify, but when the limits of the body's resistance are reached, its death occurs.

Rice. 2. Dependence of the action of an environmental factor on its intensity

Thus, for each species of plant or animal there is an optimum, stress zones and limits of stability (or endurance) in relation to each environmental factor. When the factor is close to the limits of endurance, the organism can usually exist only for a short time. In a narrower range of conditions, long-term existence and growth of individuals is possible. In an even narrower range, reproduction occurs, and the species can exist indefinitely. Typically, somewhere in the middle of the resistance range there are conditions that are most favorable for life, growth and reproduction. These conditions are called optimal, in which individuals of a given species are the most fit, i.e. leave the greatest number of descendants. In practice, it is difficult to identify such conditions, so the optimum is usually determined by individual vital signs (growth rate, survival rate, etc.).

Adaptation consists in adapting the body to environmental conditions.

The ability to adapt is one of the main properties of life in general, ensuring the possibility of its existence, the ability of organisms to survive and reproduce. Adaptations manifest themselves at different levels - from the biochemistry of cells and the behavior of individual organisms to the structure and functioning of communities and ecological systems. All adaptations of organisms to existence in various conditions have been developed historically. As a result, groupings of plants and animals specific to each geographical zone were formed.

Adaptations may be morphological, when the structure of an organism changes until a new species is formed, and physiological, when changes occur in the functioning of the body. Closely related to morphological adaptations is the adaptive coloration of animals, the ability to change it depending on the light (flounder, chameleon, etc.).

Widely known examples of physiological adaptation are winter hibernation of animals, seasonal migrations of birds.

Very important for organisms are behavioral adaptations. For example, instinctive behavior determines the action of insects and lower vertebrates: fish, amphibians, reptiles, birds, etc. This behavior is genetically programmed and inherited (innate behavior). This includes: the method of building a nest in birds, mating, raising offspring, etc.

There is also an acquired command, received by an individual in the course of his life. Education(or learning) - the main way of transmitting acquired behavior from one generation to another.

The ability of an individual to manage his cognitive abilities to survive unexpected changes in his environment is intelligence. The role of learning and intelligence in behavior increases with the improvement of the nervous system—an increase in the cerebral cortex. For humans, this is the defining mechanism of evolution. The ability of species to adapt to a particular range of environmental factors is denoted by the concept ecological mystique of the species.

The combined effect of environmental factors on the body

Environmental factors usually act not one at a time, but in a complex manner. The effect of one factor depends on the strength of the influence of others. The combination of different factors has a noticeable impact on the optimal living conditions of the organism (see Fig. 2). The action of one factor does not replace the action of another. However, with the complex influence of the environment, one can often observe a “substitution effect”, which manifests itself in the similarity of the results of the influence of different factors. Thus, light cannot be replaced by excess heat or an abundance of carbon dioxide, but by influencing temperature changes, it is possible to stop, for example, plant photosynthesis.

In the complex influence of the environment, the impact of various factors on organisms is unequal. They can be divided into main, accompanying and secondary. The leading factors are different for different organisms, even if they live in the same place. The role of a leading factor at different stages of an organism’s life can be played by one or another element of the environment. For example, in the life of many cultivated plants, such as cereals, the leading factor during the germination period is temperature, during the heading and flowering period - soil moisture, and during the ripening period - the amount of nutrients and air humidity. The role of the leading factor may change at different times of the year.

The leading factor may be different for the same species living in different physical and geographical conditions.

The concept of leading factors should not be confused with the concept of. A factor whose level in qualitative or quantitative terms (deficiency or excess) turns out to be close to the limits of endurance of a given organism, called limiting. The effect of the limiting factor will also manifest itself in the case when other environmental factors are favorable or even optimal. Both leading and secondary environmental factors can act as limiting factors.

The concept of limiting factors was introduced in 1840 by the chemist 10. Liebig. Studying the influence of the content of various chemical elements in the soil on plant growth, he formulated the principle: “The substance found in the minimum controls the yield and determines the size and stability of the latter over time.” This principle is known as Liebig's law of the minimum.

The limiting factor can be not only a deficiency, as Liebig pointed out, but also an excess of factors such as, for example, heat, light and water. As noted earlier, organisms are characterized by ecological minimums and maximums. The range between these two values ​​is usually called the limits of stability, or tolerance.

In general, the complexity of the influence of environmental factors on the body is reflected by V. Shelford’s law of tolerance: the absence or impossibility of prosperity is determined by a deficiency or, conversely, an excess of any of a number of factors, the level of which may be close to the limits tolerated by a given organism (1913). These two limits are called tolerance limits.

Numerous studies have been carried out on the “ecology of tolerance”, thanks to which the limits of existence of many plants and animals have become known. Such an example is the effect of air pollutants on the human body (Fig. 3).

Rice. 3. The influence of air pollutants on the human body. Max - maximum vital activity; Additional - permissible vital activity; Opt is the optimal (not affecting vital activity) concentration of a harmful substance; MPC is the maximum permissible concentration of a substance that does not significantly change vital activity; Years - lethal concentration

The concentration of the influencing factor (harmful substance) in Fig. 5.2 is indicated by the symbol C. At concentration values ​​of C = C years, a person will die, but irreversible changes in his body will occur at significantly lower values ​​of C = C MPC. Consequently, the range of tolerance is limited precisely by the value C MPC = C limit. Hence, Cmax must be determined experimentally for each pollutant or any harmful chemical compound and its Cmax must not be exceeded in a specific habitat (living environment).

In protecting the environment, it is important upper limits of body resistance to harmful substances.

Thus, the actual concentration of the pollutant C actual should not exceed C maximum permissible concentration (C fact ≤ C maximum permissible value = C lim).

The value of the concept of limiting factors (Clim) is that it gives the ecologist a starting point when studying complex situations. If an organism is characterized by a wide range of tolerance to a factor that is relatively constant, and it is present in the environment in moderate quantities, then such a factor is unlikely to be limiting. On the contrary, if it is known that a particular organism has a narrow range of tolerance to some variable factor, then it is this factor that deserves careful study, since it may be limiting.

Question 2. What effect does temperature have on different types of organisms?
Any type of organism is capable of living 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 occur 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 temperatures of 85-87°C. High temperatures (up to 80oC) are tolerated by some unicellular soil algae, crustose lichens, and plant seeds. There are animals and plants that can tolerate exposure to very low temperatures - until they freeze completely. As we approach the boundaries of the temperature range, 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 temperature of the environment. These are all types of invertebrate animals 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 depends on the metabolism of the body itself. These animals also develop adaptations that allow them to retain body heat (hair, dense plumage, a thick layer of subcutaneous adipose tissue, etc.).
Over 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 zonation 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 influencing the distribution of terrestrial living organisms. Lack of water leads to a number of adaptations in plants and animals.
Plants extract the water they need from the soil using their roots. Drought-resistant plants have a deep root system, smaller cells, and an increased concentration of cell sap. Water evaporation is reduced as a result of leaf reduction, the formation of a thick cuticle or waxy 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. During dry times, they remain dormant in the form of underground shoots - bulbs or rhizomes.
All land animals require periodic supply of water 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 ticks, absorb it through the integument of the body in a liquid or vapor state. In terrestrial arthropods, dense covers are formed that prevent evaporation, the metabolism is modified - insoluble products are released (uric acid, guanine). Many inhabitants of deserts and steppes (turtles, snakes) hibernate during periods of drought. A number of animals (insects, camels) use metabolic water, which is produced during the breakdown of fat, for their life. Many animal species make up for the lack of water by absorbing it when drinking or eating (amphibians, birds, mammals).

Question 4. How do organisms react to different light levels?
sunlight- the main source of energy for living organisms. Light intensity (illumination) 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 frequency.
In many animals, lighting 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 greatest ecological importance. Many animals are exclusively diurnal (most birds), others are exclusively nocturnal (many small rodents, bats, etc.). 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.
The ultraviolet part of the spectrum has high photochemical activity: in the body of animals it is involved in the synthesis of vitamin D, these rays are perceived by the visual organs of insects.
The visible part of the spectrum (red and blue rays) ensures the process of photosynthesis and the bright color of flowers (attracting pollinators). In animals, visible light is involved in spatial orientation.
Infrared rays are a source of thermal energy. Warmth is important for thermoregulation of cold-blooded animals (invertebrates and lower vertebrates). In plants, infrared radiation increases transpiration, which promotes the absorption of carbon dioxide and the movement of water throughout the plant body.
Plants and animals respond to the relationship between the length of periods of light and darkness during a 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 manifests itself 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 the migrations of birds, the change of coat in mammals, hibernation, changes in behavior, etc.

Question 5. How do pollutants affect organisms?
As a result of human economic activity, the environment is polluted by production by-products. Such pollutants include: hydrogen sulfide, sulfur dioxide, salts of heavy metals (copper, lead, zinc, etc.), radionuclides, oil refining by-products, 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 environmental disaster. Harmful substances found in water bodies, in the soil and in the atmosphere have a negative impact on plants, animals and humans.
Many pollutants act as poisons, causing the extinction of entire plant or animal species. Others can be transmitted through food chains, accumulate in the bodies of organisms, and 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 numerous direct poisonings occur with poisons, and side effects of a polluted environment are also observed (an increase in infectious diseases, cancer and diseases of various organ systems). As a rule, environmental pollution leads to a decrease in species diversity and disruption of the stability of biocenoses.