Examples of abiotic environmental factors. Environmental factors and their classification

The following groups of abiotic factors (factors of inanimate nature) are distinguished: climatic, edaphogenic (soil), orographic and chemical.

I) Climatic factors: these include solar radiation, temperature, pressure, wind and some other environmental influences.

1) Solar radiation is a powerful environmental factor. It propagates in space in the form of electromagnetic waves, of which 48% are in the visible part of the spectrum, 45% in infrared radiation (long wavelength) and about 7% in short-wave ultraviolet radiation. Solar radiation is the primary source of energy, without which life on Earth is impossible. But, on the other hand, direct exposure to sunlight (especially its ultraviolet component) is harmful to a living cell. The evolution of the biosphere was aimed at reducing the intensity of the ultraviolet part of the spectrum and protecting against excess solar radiation. This was facilitated by the formation of ozone (ozone layer) from oxygen released by the first photosynthetic organisms.

The total amount of solar energy reaching the Earth is approximately constant. But different points on the earth’s surface receive different amounts of energy (due to differences in the time of illumination, different angles of incidence, degree of reflection, transparency of the atmosphere, etc.)

A close connection has been revealed between solar activity and the rhythm of biological processes. The greater the solar activity (more sunspots), the more disturbances in the atmosphere, magnetic storms affecting living organisms. An important role is also played by the change in solar activity during the day, which determines the circadian rhythms of the body. In humans, more than 100 physiological characteristics are subject to the daily cycle (hormone secretion, respiratory rate, functioning of various glands, etc.)

Solar radiation largely determines other climatic factors.

2) Ambient temperature is related to the intensity of solar radiation, especially the infrared part of the spectrum. The life activity of most organisms proceeds normally in the temperature range from +5 to 40 0 C. Above +50 0 − +60 0, irreversible destruction of the protein that is part of living tissues begins. At high pressures, the upper temperature limit can be much higher (up to +150−200 0 C). The lower temperature limit is often less critical. Some living organisms are able to withstand very low temperatures (up to −200 0 C) in a state of suspended animation. Many organisms in the Arctic and Antarctic constantly live at subzero temperatures. Some Arctic fish have a normal body temperature of −1.7 0 C. However, the water in their narrow capillaries does not freeze.

The dependence of the intensity of vital activity of most living organisms on temperature has the following form:

Fig. 12. Dependence of vital activity of organisms on temperature

As can be seen from the figure, as the temperature rises, biological processes accelerate (the rate of reproduction and development, the amount of food consumed). For example, the development of cabbage butterfly caterpillars at +10 0 C requires 100 days, and at +26 0 C - only 10 days. But a further increase in temperature leads to a sharp decrease in vital parameters and death of the organism.

In water, the range of temperature fluctuations is smaller than on land. Therefore, aquatic organisms are less adapted to temperature changes than terrestrial ones.

Temperature often determines zonality in terrestrial and aquatic biogeocenoses.

3) Ambient humidity is an important environmental factor. Most living organisms consist of 70–80% water, a substance necessary for the existence of protoplasm. The humidity of the area is determined by the humidity of the atmospheric air, the amount of precipitation, and the area of water reserves.

Air humidity depends on temperature: the higher it is, the more water is usually contained in the air. The lower layers of the atmosphere are richest in moisture. Precipitation is the result of condensation of water vapor. In the temperate climate zone, the distribution of precipitation by season is more or less uniform, in the tropics and subtropics it is uneven. The available supply of surface water depends on underground sources and rainfall.

The interaction of temperature and humidity forms two climates: maritime and continental.

4) Pressure is another climatic factor that is important for all living organisms. There are areas on Earth with permanently high or low pressure. Pressure drops are associated with unequal heating of the earth's surface.

5) Wind is the directional movement of air masses resulting from pressure differences. The wind flow is directed from an area with high pressure to an area with lower pressure. It affects temperature, humidity and the movement of impurities in the air.

6) Lunar rhythms determine the ebb and flow of tides, to which marine animals are adapted. They use the ebb and flow of tides for many life processes: movement, reproduction, etc.

ii) Edaphogenic factors determine various soil characteristics. Soil plays an important role in terrestrial ecosystems - the role of a reservoir and reserve of resources. The composition and properties of soils are strongly influenced by climate, vegetation and microorganisms. Steppe soils are more fertile than forest soils, since grasses are short-lived and each year a large amount of organic matter enters the soil, which quickly decomposes. Ecosystems without soil are usually very unstable. The following main characteristics of soils are distinguished: mechanical composition, moisture capacity, density and air permeability.

The mechanical composition of soils is determined by the content of particles of different sizes in it. There are four types of soils, depending on their mechanical composition: sand, sandy loam, loam, clay. The mechanical composition directly affects plants, underground organisms, and through them, other organisms. The moisture capacity (the ability to retain moisture), their density and air permeability of soils depend on the mechanical composition.

III) Orographic factors. These include the height of the area above sea level, its relief and location relative to the cardinal points. Orographic factors largely determine the climate of a given area, as well as other biotic and abiotic factors.

IV) Chemical factors. These include the chemical composition of the atmosphere (gas composition of the air), lithosphere, and hydrosphere. For living organisms, the content of macro- and microelements in the environment is of great importance.

Macroelements are elements required by the body in relatively large quantities. For most living organisms these are phosphorus, nitrogen, potassium, calcium, sulfur, magnesium.

Microelements are elements required by the body in extremely small quantities, but are part of vital enzymes. Microelements are necessary for the normal functioning of the body. The most common microelements are metals, silicon, boron, chlorine.

There is no clear boundary between macroelements and microelements: what is a microelement for some organisms is a macroelement for another.

Classification of environmental factors.

ENVIRONMENTAL FACTORS

4.1. Classification of environmental factors.

4.2. Abiotic factors

4.3. Biotic factors

4.3. Ecological plasticity. The concept of a limiting factor

From an ecological position, the environment is natural bodies and phenomena with which the organism is in direct or indirect relationships.

The environment surrounding an organism is characterized by enormous diversity, consisting of many elements, phenomena, conditions that are dynamic in time and space, which are considered as factors.

Environmental factor- this is any environmental condition that can have a direct or indirect effect on living organisms, at least during one of the phases of their individual development, or any environmental condition to which the organism adapts. In turn, the body reacts to the environmental factor with specific adaptive reactions.

Environmental environmental factors are divided into three categories:

1) factors of inanimate nature (abiotic);

2) factors of living nature (biotic);

3) anthropogenic.

Of the many existing classifications of environmental factors, it is advisable to use the following for the purposes of this course (Fig. 1).

Rice. 4.1. Classification of environmental factors

Anthropogenic factors- these are all forms of activity of human society that change nature as the habitat of living organisms or directly affect their lives. The separation of anthropogenic factors into a separate group is due to the fact that currently the fate of the Earth's vegetation and all currently existing species of organisms is practically in the hands of human society.

All environmental factors in general can be grouped into two large categories: factors of inanimate, or inert, nature, otherwise called abiotic or abiogenic, and factors of living nature - biotic or biogenic. But in their origin, both groups can be like natural, so anthropogenic, i.e. related to human influence. Sometimes they distinguish anthropic And anthropogenic factors. The first includes only direct human impacts on nature (pollution, fishing, pest control), and the second includes mainly indirect consequences associated with changes in the quality of the environment.

Along with the one discussed, there are other classifications of environmental factors. Factors are identified dependent And independent of the number and density of organisms. For example, climatic factors do not depend on the number of animals and plants, and mass diseases caused by pathogenic microorganisms (epidemics) in animals or plants are certainly associated with their numbers: epidemics occur when there is close contact between individuals or when they are generally weakened due to a lack of feed, when rapid transmission of the pathogen from one individual to another is possible, and resistance to the pathogen is also lost.

The macroclimate does not depend on the number of animals, but the microclimate can change significantly as a result of their life activity. If, for example, insects, with their high numbers in the forest, destroy most of the needles or foliage of trees, then the wind regime, illumination, temperature, quality and quantity of food will change here, which will affect the condition of subsequent generations of the same or other animals living here. Mass reproduction of insects attracts insect predators and insectivorous birds. Harvests of fruits and seeds influence changes in the population of mouse-like rodents, squirrels and their predators, as well as many seed-eating birds.

All factors can be divided into regulating (managing) And adjustable (controlled), which is also easy to understand in connection with the above examples.

The original classification of environmental factors was proposed by A.S. Monchadsky. He proceeded from the idea that all adaptive reactions of organisms to certain factors are associated with the degree of constancy of their influence, or, in other words, with their periodicity. In particular, he highlighted:

1. primary periodic factors(those that are characterized by the correct periodicity associated with the rotation of the Earth: the change of seasons, daily and seasonal changes in illumination and temperature); these factors were originally inherent in our planet and nascent life had to immediately adapt to them;

2. secondary periodic factors(they are derived from the primary ones); these include all physical and many chemical factors, such as humidity, temperature, precipitation, population dynamics of plants and animals, the content of dissolved gases in water, etc.;

3. non-periodic factors, which are not characterized by correct periodicity (cyclicity); These are, for example, factors associated with the soil, or various types of natural phenomena.

Of course, only the soil body itself and the underlying soils are “non-periodic”, and the dynamics of temperature, humidity and many other properties of the soil are also associated with primary periodic factors.

Anthropogenic factors are definitely non-periodic. Among such non-periodic factors, first of all, are pollutants contained in industrial emissions and discharges. In the process of evolution, living organisms are able to develop adaptations to natural periodic and non-periodic factors (for example, hibernation, wintering, etc.), and to changes in the content of impurities in water or air, plants and animals, as a rule, cannot acquire and hereditarily fix the corresponding adaptation. True, some invertebrates, for example, herbivorous mites from the class of arachnids, which have dozens of generations a year in closed ground conditions, are capable of forming races resistant to poison by constantly using the same pesticides against them by selecting individuals that inherit such resistance.

It must be emphasized that the concept of “factor” should be approached in a differentiated manner, taking into account that factors can be of both direct (immediate) and indirect action. The differences between them are that the direct factor can be quantified, while the indirect factors cannot. For example, climate or relief can be designated mainly verbally, but they determine the regimes of direct action factors - humidity, daylight hours, temperature, physical and chemical characteristics of the soil, etc.

Abiotic factors is a set of properties of inanimate nature that are important for organisms.

The abiotic component of the terrestrial environment represents a set of climatic and soil factors that influence both each other and living beings.

Temperature

The range of temperatures existing in the Universe is 1000 degrees, and in comparison with it, the limits within which life can exist are very narrow (about 300 0) from -200 0 C to +100 0 C (in hot springs at the bottom of the Pacific Ocean at the entrance to Bacteria were discovered in the Gulf of California for which the optimal temperature is 250 0 C). Most species and most activity are confined to an even narrower range of temperatures. The upper temperature limit for bacteria in hot springs is about 88 0 C, for blue-green algae about 80 0 C, and for the most resistant fish and insects - about 50 0 C.

The range of temperature fluctuations in water is smaller than on land, and the range of temperature tolerance in aquatic organisms is narrower than in terrestrial animals. Thus, temperature is an important and very often limiting factor. Temperature very often creates zonation and stratification in aquatic and terrestrial habitats. Easily measurable.

Temperature variability is extremely important from an environmental point of view. The vital activity of organisms that in nature are usually exposed to variable temperatures is suppressed partially or completely or slowed down when exposed to constant temperature.

It is known that the amount of heat falling on a horizontal surface is directly proportional to the sine of the angle of the sun above the horizon. Therefore, in the same areas, daily and seasonal temperature fluctuations are observed, and the entire surface of the globe is divided into a number of zones with conventional boundaries. The higher the latitude of the area, the greater the angle of inclination of the sun's rays to the surface of the earth and the colder the climate.

Radiation, light.

With regard to light, organisms face a dilemma: on the one hand, the direct effect of light on protoplasm is fatal to organisms, on the other hand, light serves as the primary source of energy, without which life is impossible. Therefore, many morphological and behavioral characteristics of organisms are associated with solving this problem. The evolution of the biosphere as a whole was aimed mainly at taming incoming solar radiation, using its beneficial components and weakening harmful ones or protecting against them. Illumination plays a vital role for all living things, and organisms are physiologically adapted to the cycle of day and night, to the ratio of dark and light periods of the day. Almost all animals have circadian rhythms associated with the cycle of day and night. In relation to light, plants are divided into light-loving and shade-loving.

Radiation consists of electromagnetic waves of different lengths. Light corresponding to two regions of the spectrum easily passes through the Earth's atmosphere. This is visible light (48%) and its neighboring regions (UV - 7%, IR - 45%), as well as radio waves with a length of more than 1 cm. Visible, i.e. The spectral region perceived by the human eye covers the wave range from 390 to 760 nm. Infrared rays are of primary importance for life, and in the processes of photosynthesis, orange-red and ultraviolet rays play the most important role. The amount of solar radiation energy passing through the atmosphere to the Earth's surface is almost constant and is estimated at approximately 21 * 10 23 kJ. This quantity is called the solar constant. But the arrival of solar energy at different points on the Earth’s surface is not the same and depends on the length of the day, the angle of incidence of the rays, the transparency of the atmospheric air, etc. Therefore, the solar constant is often expressed in the number of joules per 1 cm 2 of surface per unit time. Its average value is about 0.14 J/cm2 per 1s. Radiant energy is associated with the illumination of the earth's surface, which is determined by the duration and intensity of the light flux.

Solar energy is not only absorbed by the earth's surface, but also partially reflected by it. The general regime of temperature and humidity depends on what proportion of solar radiation energy is absorbed by the surface.

Ambient air humidity

Associated with its saturation with water vapor. The lower layers of the atmosphere are richest in moisture (1.5 - 2.0 km), where about 50% of all moisture is concentrated. The amount of water vapor contained in the air depends on the air temperature. The higher the temperature, the more moisture the air contains. However, at a specific air temperature, there is a certain limit of saturation with water vapor, which is called the maximum. Typically, the saturation of air with water vapor does not reach the maximum, and the difference between the maximum and this saturation is called moisture deficiency. Humidity deficiency is the most important environmental parameter, because it characterizes two quantities at once: temperature and humidity. The higher the moisture deficit, the drier and warmer it is and vice versa. An increase in moisture deficiency during certain periods of the growing season promotes increased fruiting of plants, and in a number of animals, such as insects, leads to reproduction up to outbreaks.

Precipitation

Precipitation is the result of condensation of water vapor. Due to condensation, dew and fog are formed in the ground layer of air, and at low temperatures crystallization of moisture (frost) is observed. Due to condensation and crystallization of water vapor in higher layers of the atmosphere, clouds and precipitation are formed. Precipitation is one of the links in the water cycle on Earth, and a sharp unevenness can be traced in its precipitation, and therefore humid (wet) and arid (arid) zones are distinguished. The maximum amount of precipitation falls in the tropical forest zone (up to 2000 mm per year), while in arid zones it is 0.18 mm. per year (in the tropical desert). Zones with precipitation less than 250mm. per year are considered dry.

Gas composition of the atmosphere

The composition is relatively constant and includes predominantly nitrogen and oxygen, with an admixture of CO 2 and Ar (argon). The upper layers of the atmosphere contain ozone. There are solid and liquid particles (water, oxides of various substances, dust and fumes). Nitrogen is the most important biogenic element involved in the formation of protein structures of organisms; oxygen - provides oxidative processes, respiration; Ozone has a shielding role in relation to the UV part of the solar spectrum. Impurities of tiny particles affect the transparency of the atmosphere, preventing the passage of sunlight to the surface of the Earth.

Movement of air masses (wind).

The cause of wind is unequal heating of the earth's surface associated with pressure changes. The wind flow is directed towards lower pressure, i.e. to where the air is warmer. In the surface layer of air, the movement of air masses affects the regime of temperature, humidity, evaporation from the Earth's surface and transpiration of plants. Wind is an important factor in the transfer and distribution of impurities in the atmospheric air.

Atmospheric pressure.

A normal pressure is 1 kPa, corresponding to 750.1 mm. rt. Art. Within the globe there are constant areas of high and low pressure, and seasonal and daily minimums and maximums of pressure are observed at the same points.

Lecture No. 5

Ecological environmental factors. Abiotic factors

The concept of environmental factor

Classification

Abiotic factors

General patterns of distribution of levels and regional regimes of environmental factors
Space factors
Radiant energy from the Sun and its significance for organisms
Abiotic factors of the terrestrial environment (temperature, precipitation, humidity, movement of air masses, pressure, chemical factors, fires)
Abiotic factors of the aquatic environment (temperature stratification, transparency, salinity, dissolved gases, acidity)
Abiotic factors of soil cover (lithosphere composition, concepts of “soil” and “fertility”, composition and structure of soils)
Nutrients as an environmental factor

1. Environmental factor- this is any element of the environment that can have a direct or indirect effect on a living organism at least at one of the stages of its individual development, or any environmental condition to which the organism responds with adaptive reactions.

In general, a factor is a driving force of a process or a condition affecting the body. The environment is characterized by a huge variety of environmental factors, including those that are not yet known. Every living organism throughout its life is under the influence of many environmental factors that differ in origin, quality, quantity, time of exposure, i.e. regime. Thus, the environment is actually a set of environmental factors affecting the body.

But if the environment, as we have already said, does not have quantitative characteristics, then each individual factor (be it humidity, temperature, pressure, food proteins, the number of predators, a chemical compound in the air, etc.) is characterized by measure and number, i.e. That is, it can be measured in time and space (in dynamics), compared with some standard, subjected to modeling, prediction (forecast) and ultimately changed in a given direction. You can only control what has measure and number.

For an enterprise engineer, economist, sanitary doctor or prosecutor's office investigator, the requirement to “protect the environment” does not make sense. And if the task or condition is expressed in quantitative form, in the form of any quantities or inequalities (for example: C i< ПДК i или M i < ПДВ i то они вполне понятны и в практическом, и в юридическом отношении. Задача предприятия - не "охранять природу", а с помощью инженерных или организационных приемов выполнить названное условие, т. е. именно таким путем управлять качеством окружающей среды, чтобы она не представляла угрозы здоровью людей. Обеспечение выполнения этих условий - задача контролирующих служб, а при невыполнении их предприятие несет ответственность.

2. Classification of environmental factors

Any classification of any set is a method of its cognition or analysis. Objects and phenomena can be classified according to various criteria, based on the assigned tasks. Of the many existing classifications of environmental factors, it is advisable to use the following for the purposes of this course (Fig. 1).

All environmental factors can generally be grouped into two large categories: factors of inanimate, or inert, nature, otherwise called abiotic or abiogenic, and factors of living nature - biotic, or biogenic. But in their origin, both groups can be like natural, so anthropogenic, i.e. related to human influence. Sometimes they distinguish anthropic And anthropogenic factors. The first includes only direct human impacts on nature (pollution, fishing, pest control), and the second includes mainly indirect consequences associated with changes in the quality of the environment.

Rice. 1. Classification of environmental factors

In his activities, man not only changes the regimes of natural environmental factors, but also creates new ones, for example, by synthesizing new chemical compounds - pesticides, fertilizers, medicines, synthetic materials, etc. Among the factors of inanimate nature are physical(space, climatic, orographic, soil) and chemical(components of air, water, acidity and other chemical properties of the soil, impurities of industrial origin). Biotic factors include zoogenic(influence of animals), phytogenic(influence of plants), microgenic(influence of microorganisms). In some classifications, biotic factors include all anthropogenic factors, including physical and chemical.

Along with the one discussed, there are other classifications of environmental factors. Factors are identified dependent and independent on the number and density of organisms. For example, climatic factors do not depend on the number of animals and plants, and mass diseases caused by pathogenic microorganisms (epidemics) in animals or plants are certainly associated with their numbers: epidemics occur when there is close contact between individuals or when they are generally weakened due to a lack of feed, when rapid transmission of the pathogen from one individual to another is possible, and resistance to the pathogen is also lost.

All factors can be divided into regulating(managers) and adjustable(controlled), which is also easy to understand in connection with the above examples.

The original classification of environmental factors was proposed by A. S. Monchadsky. He proceeded from the idea that all adaptive reactions of organisms to certain factors are associated with the degree of constancy of their influence, or, in other words, with their periodicity. In particular, he highlighted:

1. primary periodic factors (those that are characterized by the correct periodicity associated with the rotation of the Earth: the change of seasons, daily and seasonal changes in illumination and temperature); these factors were originally inherent in our planet and nascent life had to immediately adapt to them;

2. secondary periodic factors (they are derived from the primary ones); these include all physical and many chemical factors, such as humidity, temperature, precipitation, population dynamics of plants and animals, the content of dissolved gases in water, etc.;

3. non-periodic factors that are not characterized by regular periodicity (cyclicity); These are, for example, factors associated with the soil, or various types of natural phenomena.

3. Abiotic factors

3.1. General patterns of distribution of levels and regional regimes of environmental factors

The geographical envelope of the Earth (like the General biosphere) is heterogeneous in space; it is differentiated into territories that differ from each other. It is successively divided into physical-geographical zones, geographic zones, intrazonal mountain and plain regions and subregions and subzones, etc.

Physiographic zone- this is the largest taxonomic unit of the geographical envelope, consisting of a number of geographical zones that are similar in heat balance and moisture regime.

There are, in particular, Arctic and Antarctic, subarctic and subantarctic, northern and southern temperate and subtropical, subequatorial and equatorial belts.

A geographic (also known as natural, landscape) zone is a significant part of a physical-geographical zone with a special character of geomorphological processes, with special types of climate, vegetation, soil, flora and fauna.

For example, within the northern hemisphere, the following zones are distinguished: ice, tundra, forest-tundra, taiga, mixed forests of the Russian Plain, monsoon forests of the Far East, forest-steppe, steppe, desert temperate and subtropical zones, Mediterranean, etc. The zones have predominantly (although not always ) are elongated in broad terms and are characterized by similar natural conditions, a certain sequence depending on the latitudinal position. Thus, latitudinal geographic zoning is a natural change in physical-geographical processes, components and complexes from the equator to the poles. It is clear that we are talking primarily about the combination of factors that form the climate.

Zoning is determined mainly by the nature of the distribution of solar energy across latitudes, i.e., with a decrease in its arrival from the equator to the poles and uneven moisture. The position on the zonality of the geographic envelope (and, consequently, the biosphere) was formulated by the famous Russian soil scientist V.V. Dokuchaev.

Along with the latitude, there is also a vertical (or altitudinal) zonation typical for mountainous regions, i.e. a change in vegetation, fauna, soils, climatic conditions as one rises from sea level, associated mainly with a change in the heat balance: the air temperature difference is 0.6-1.0 °C for every 100 m of height.

Of course, in nature, not everything is so unambiguously regular: vertical zoning can be complicated by slope exposure, and latitudinal zoning can have zones elongated in the submeridional direction, as, for example, in the conditions of mountain ranges.

However, in general, the regimes and dynamics of the most important abiotic factors depend on the heat balance, i.e. climate, soil formation processes, types of vegetation, species composition and population dynamics of the animal world, etc.

Geographic zoning is inherent not only to the continents, but also to the World Ocean, within which different zones differ in the amount of incoming solar radiation, balances of evaporation and precipitation, water temperature, characteristics of surface and deep currents, and, consequently, the world of living organisms.

3.2. Space factors

The biosphere, as a habitat for living organisms, is not isolated from complex processes occurring in outer space, which are directly related not only to the Sun. Cosmic dust and meteorite matter fall to Earth. The Earth periodically collides with asteroids and comes close to comets. Materials and waves resulting from supernova explosions pass through the Galaxy. Of course, our planet is most closely connected with the processes occurring on the Sun - with the so-called solar activity. The essence of this phenomenon is the transformation of energy accumulated in the magnetic belts of the Sun into the energy of movement of gas masses, fast particles, and short-wave electromagnetic radiation.

The most intense processes are observed in centers of activity, called active regions, in which an intensification of the magnetic field is observed, areas of increased brightness, as well as so-called sunspots, appear. In active regions, explosive releases of energy can occur, accompanied by plasma emissions, the sudden appearance of solar cosmic rays, and an increase in short-wave and radio emission. It is known that changes in the level of flare activity are cyclical, with a typical cycle of 22 years, although fluctuations with a periodicity of 4.3 to 1850 years are known. Solar activity influences a number of life processes on Earth - from the occurrence of epidemics and surges in birth rates to major climatic changes. This was proven back in 1915 by the Russian scientist A.L. Chizhevsky, the founder of a new science - heliobiology (from the Greek helios - Sun), which examines the impact of changes in the activity of the Sun on the Earth's biosphere.

3.3. Radiant energy from the Sun and its significance for organisms

The energy of solar radiation propagates in space in the form of electromagnetic waves. About 99% of it is made up of rays with a wavelength of 170-4000 nm, including 48% in the visible part of the spectrum with a wavelength of 400-760 nm, and 45% in the infrared (wavelength from 750 nm to 10~3 m) , about 7% for ultraviolet (wavelength less than 400 nm). In the processes of photosynthesis, photosynthetically active radiation (380-710 nm) plays the most important role.

The amount of solar radiation energy reaching the Earth (to the upper boundary of the atmosphere) is almost constant and is estimated at 1370 W/m2. This value is called the solar constant. However, the arrival of solar radiation energy to the surface of the Earth itself varies significantly depending on a number of conditions: the height of the Sun above the horizon, latitude, state of the atmosphere, etc. The shape of the Earth (geoid) is close to spherical. Therefore, the greatest amount of solar energy is absorbed in low latitudes (equatorial belt), where the air temperature near the earth's surface is usually higher than in middle and high latitudes. The arrival of solar radiation energy in different regions of the globe and its redistribution determine the climatic conditions of these regions.

Passing through the atmosphere, solar radiation is scattered on gas molecules, suspended impurities (solid and liquid), and absorbed by water vapor, ozone, carbon dioxide, and dust particles. Scattered solar radiation partially reaches the earth's surface. Its visible part creates light during the day in the absence of direct sunlight, for example in heavy clouds. The total flow of heat to the Earth's surface depends on the sum of direct and scattered radiation, which increases from the poles to the equator.

The energy of solar radiation is not only absorbed by the Earth's surface, but also reflected by it in the form of a stream of long-wave radiation. Lighter colored surfaces reflect light more intensely than darker ones. So, clean snow reflects 80-95%, contaminated snow - 40-50, chernozem soil - 5-14, light sand - 35-45, forest canopy - 10-18%. The ratio of the flux of solar radiation reflected by the surface to that received is called albedo. Anthropogenic activity significantly influences climatic factors, changing their regimes. You can learn about global problems caused by human activity in the lecture “Global Problems of Humanity” in this course.

Light is the primary source of energy, without which life on Earth is impossible. It participates in photosynthesis, ensuring the creation of organic compounds from inorganic plants of the Earth, and this is its most important energy function. But only a part of the spectrum in the range from 380 to 760 nm, which is called the region of physiologically active radiation (PAR), is involved in photosynthesis. Within it, for photo synthesis, red-orange rays (600-700 nm) and violet-blue (400-500 nm) are of greatest importance, and yellow-green (500-600 nm) are the least important. The latter are reflected, which gives chlorophyll-bearing plants their green color. However, light is not only an energy resource, but also the most important environmental factor, which has a very significant impact on the biota as a whole and on adaptation processes and phenomena in organisms.

Outside the visible spectrum and PAR are the infrared (IR) and ultraviolet (UV) regions. UV radiation carries a lot of energy and has a photochemical effect - organisms are very sensitive to it. IR radiation has significantly less energy and is easily absorbed by water, but some land organisms use it to raise body temperature above ambient.

Light intensity is important for organisms. Plants in relation to illumination are divided into light-loving (heliophytes), shade-loving (sciophytes) and shade-tolerant.

The first two groups have different tolerance ranges within the ecological light spectrum. Bright sunlight is the optimum for heliophytes (meadow grasses, cereals, weeds, etc.), low light is the optimum for shade-loving plants (plants of taiga spruce forests, forest-steppe oak forests, tropical forests). The former cannot stand shadows, the latter cannot stand bright sunlight.

Shade-tolerant plants have a wide range of light tolerance and can grow in both bright light and shade.

Light has a great signaling value and causes regulatory adaptations in organisms. One of the most reliable signals that regulate the activity of organisms over time is the length of the day - the photoperiod.

Photoperiodism as a phenomenon is the body's response to seasonal changes in day length. The length of the day in a given place, at a given time of year, is always the same, which allows plants and animals to determine the time of year at a given latitude, i.e., the time of the beginning of flowering, ripening, etc. In other words, the photoperiod is a kind of “time relay” ", or "trigger mechanism", including a sequence of physiological processes in a living organism.

Photoperiodism cannot be identified with ordinary external circadian rhythms, caused simply by the change of day and night. However, the daily cyclicity of life in animals and humans turns into the innate properties of the species, that is, it becomes internal (endogenous) rhythms. But unlike the initially internal rhythms, their duration may not coincide with the exact number - 24 hours - by 15-20 minutes, and in connection with this, such rhythms are called circadian (in translation - close to a day).

These rhythms help the body sense time, an ability called the “biological clock.” They help birds navigate by the sun during migration and generally orient organisms in the more complex rhythms of nature.

Photoperiodism, although hereditarily fixed, manifests itself only in combination with other factors, for example, temperature: if it is cold on day X, then the plant blooms later, or in the case of ripening - if the cold comes earlier than day X, then, say, potatoes produce low harvest, etc. In the subtropical and tropical zones, where the length of the day varies little by season, the photoperiod cannot serve as an important environmental factor - it is replaced by an alternation of dry and rainy seasons, and in the highlands the main signaling factor becomes temperature.

Just as on plants, weather conditions affect poikilothermic animals, and homeothermic animals respond to this with changes in their behavior: the timing of nesting, migration, etc. changes.

Man has learned to use the phenomena described above. The length of daylight hours can be changed artificially, thereby changing the timing of flowering and fruiting of plants (growing seedlings in winter and even fruits in greenhouses), increasing the egg production of chickens, etc.

The development of living nature by season occurs in accordance with the bioclimatic law, which bears the name of Hoyakins: the timing of the onset of various seasonal phenomena (phenodate) depends on the latitude, longitude of the area and its altitude above sea level. This means that the further north, east and higher the terrain, the later spring comes and the earlier autumn comes. For Europe, at each degree of latitude, the timing of seasonal events occurs after three days, in North America - on average, after four days for each degree of latitude, at five degrees of longitude and at 120 m above sea level.

Knowledge of phenodata is of great importance for planning various agricultural work and other economic activities.

3.4. Abiotic factors of the terrestrial environment

The abiotic component of the terrestrial environment (land) includes a set of climatic and soil conditions, i.e., many elements that are dynamic in time and space, connected with each other and influencing living organisms.

The peculiarities of the impact on the biosphere from cosmic factors and manifestations of solar activity are that the surface of our planet (where the “film of life” is concentrated) is, as it were, separated from Space by a thick layer of matter in a gaseous state, i.e., the atmosphere. The abiotic component of the terrestrial environment includes a set of climatic, hydrological, soil and soil conditions, i.e., many elements that are dynamic in time and space, interconnected and influencing living organisms. The atmosphere, as a medium that perceives cosmic and solar-related factors, has the most important climate-forming function.

The effect of temperature on organisms

Temperature is the most important limiting factor. The limits of tolerance for any species are the maximum and minimum lethal temperatures, beyond which the species is fatally affected by heat or cold (Fig. 2.). Apart from some unique exceptions, all living things are capable of living at temperatures between 0 and 50 ° C, which is due to the properties of the protoplasm of cells.

In Fig. 2. The temperature limits of life of a species group or population are shown. In the “optimal interval,” organisms feel comfortable, actively reproduce, and the population grows. Towards the extremes of the temperature limit of life - “reduced vital activity” - organisms feel depressed. With further cooling within the “lower limit of resistance” or an increase in heat within the “upper limit of resistance”, organisms enter the “death zone” and die.

This example illustrates the general law of biological resistance (according to Lamott), applicable to any of the important limiting factors. The value of the “optimal interval” characterizes the “magnitude” of the resistance of organisms, i.e., the value of its tolerance to this factor, or “ecological valency”.

Adaptation processes in animals in relation to temperature led to the emergence of poikilothermic and homeothermic animals. The vast majority of animals are poikilothermic, i.e., the temperature of their own body changes with changes in the temperature of the environment: amphibians, reptiles, insects, etc. A significantly smaller proportion of animals are homeothermic, i.e., they have a constant body temperature, independent of the temperature of the external environment : mammals (including humans) with a body temperature of 36-37 0 C, and birds with a body temperature of 40 ° C.

Rice. 2. General law of biological resistance (according to M. Lamott)

Only homeothermic animals can lead an active life at temperatures below zero. Although poikilotherms can withstand temperatures well below zero, they lose mobility. A temperature of about 40 °C, i.e. even below the protein coagulation temperature, is the limit for most animals.

Temperature plays no less important role in the life of plants. When the temperature rises by 10 °C, the intensity of photosynthesis doubles, but only up to 30-35 °C, then its intensity drops, and at 40-45 °C photosynthesis stops altogether. At 50 °C, most terrestrial plants die, which is associated with the intensification of plant respiration when the temperature rises, and then its cessation at 50 0 C.

Temperature also affects the course of root nutrition in plants: this process is possible only if the soil temperature in the suction areas is several degrees lower than the temperature of the above-ground part of the plant. Violation of this balance entails inhibition of plant life and even death. Morphological adaptations of plants to low temperatures are known, the so-called life forms of plants, for example, epiphytes, phanerophytes, etc.

Morphological adaptations to the temperature conditions of life, and above all, are also observed in animals. Life farms of animals of the same species, for example, can be formed under the influence of low temperatures, from -20 to -40 0 C, at which they are forced to accumulate nutrients and increase body weight: of all tigers, the largest is the Amur tiger, living in the most northern and harsh conditions. This pattern is called Bergmann's rule: in warm-blooded animals, the body size of individuals is, on average, larger in populations living in colder parts of the species' distribution range.

But in the life of animals, physiological adaptations are much more important, the simplest of which is acclimatization - a physiological adaptation to withstand heat or cold. For example, the fight against overheating by increasing evaporation, the fight against cooling in poikilothermic animals by partial dehydration of their body or the accumulation of special substances that lower the freezing point, in homeothermic animals - by changing metabolism.

There are also more radical forms of protection from the cold - migration to warmer regions (bird migration; high-mountain chamois move to lower altitudes for the winter, etc.), wintering - hibernation for the winter (marmot, squirrel, brown bear, flying mice: they are able to lower their body temperature to almost zero, slowing down their metabolism and, thereby, the waste of nutrients).

Introduction

Every day, rushing about business, you walk down the street, shivering from the cold or sweating from the heat. And after a working day, you go to the store and buy food. Leaving the store, you hastily stop a passing minibus and helplessly sit down on the nearest empty seat. For many, this is a familiar way of life, isn't it? Have you ever thought about how life works from an environmental point of view? The existence of humans, plants and animals is possible only through their interaction. It cannot do without the influence of inanimate nature. Each of these types of impact has its own designation. So, there are only three types of impact on the environment. These are anthropogenic, biotic and abiotic factors. Let's look at each of them and its impact on nature.

1. Anthropogenic factors - influence on the nature of all forms of human activity

When this term is mentioned, not a single positive thought comes to mind. Even when people do something good for animals and plants, it happens because of the consequences of previously doing something bad (for example, poaching).

Anthropogenic factors (examples):

Drying swamps.
Fertilizing fields with pesticides.
Poaching.
Industrial waste (photo).

Conclusion

As you can see, basically people only cause harm to the environment. And due to the increase in economic and industrial production, even environmental measures established by rare volunteers (the creation of nature reserves, environmental rallies) are no longer helping.

2. Biotic factors - the influence of living nature on various organisms

Simply put, it is the interaction of plants and animals with each other. It can be both positive and negative. There are several types of such interaction:

1. Competition - such relationships between individuals of the same or different species in which the use of a certain resource by one of them reduces its availability for others. In general, in competition, animals or plants fight among themselves for their piece of bread

2. Mutualism is a relationship in which each species receives a certain benefit. Simply put, when plants and/or animals complement each other harmoniously.

3. Commensalism is a form of symbiosis between organisms of different species, in which one of them uses the host’s home or organism as a place of settlement and can feed on food remains or products of its vital activity. At the same time, it brings neither harm nor benefit to the owner. All in all, a small, unnoticeable addition.

Biotic factors (examples):

Coexistence of fish and coral polyps, flagellated protozoans and insects, trees and birds (eg woodpeckers), mynah starlings and rhinoceroses.

Conclusion

Despite the fact that biotic factors can be harmful to animals, plants and humans, they also have great benefits.

3. Abiotic factors - the impact of inanimate nature on a variety of organisms

Yes, and inanimate nature also plays an important role in the life processes of animals, plants and humans. Perhaps the most important abiotic factor is weather.

Abiotic factors: examples

Abiotic factors are temperature, humidity, light, salinity of water and soil, as well as the air and its gas composition.

Conclusion

Abiotic factors can be harmful to animals, plants and humans, but they still generally benefit them

Bottom line

The only factor that does not benefit anyone is anthropogenic. Yes, it also does not bring anything good to a person, although he is sure that he is changing nature for his own good, and does not think about what this “good” will turn into for him and his descendants in ten years. Humans have already completely destroyed many species of animals and plants that had their place in the world ecosystem. The Earth's biosphere is like a film in which there are no minor roles, all of them are the main ones. Now imagine that some of them were removed. What will happen in the film? This is how it is in nature: if the smallest grain of sand disappears, the great building of Life will collapse.

The impact of environmental factors on living organisms individually and communities as a whole is multifaceted. When assessing the influence of a particular environmental factor, it is important to characterize the intensity of its action on living matter: in favorable conditions they speak of an optimal factor, and in case of excess or deficiency - a limiting factor.

Temperature. Most species are adapted to a fairly narrow temperature range. Some organisms, especially in the resting stage, are able to exist at very low temperatures. For example, microbial spores can withstand cooling down to -200 °C. Certain types of bacteria and algae can live and reproduce in hot springs at temperatures from +80 to -88 ° C. The range of temperature fluctuations in water is much smaller than on land, and accordingly, the limits of resistance to temperature fluctuations in aquatic organisms are narrower than in terrestrial ones. However, for both aquatic and terrestrial inhabitants, the optimal temperature is in the range from +15 to +30 °C.

There are organisms with an unstable body temperature - poikilothermic (from the Greek. poikilos- various, changeable and thermo- heat) and organisms with a constant body temperature - homeothermic (from the Greek. homoios- similar and thermo- warm). The body temperature of poikilothermic organisms depends on the ambient temperature. Its increase causes them to intensify their life processes and, within certain limits, accelerate their development.

In nature, temperature is not constant. Organisms that are typically exposed to seasonal temperature fluctuations, such as those found in temperate zones, are less able to tolerate constant temperatures. Sharp temperature fluctuations - severe frosts or heat - are also unfavorable for organisms. There are many devices to combat cooling or overheating. With the onset of winter, plants and poikilothermic animals enter a state of winter dormancy. The metabolic rate decreases sharply, and a lot of fats and carbohydrates are stored in the tissues. The amount of water in the cells decreases, sugars and glycerol accumulate, which prevent freezing. During the hot season, physiological mechanisms are activated that protect against overheating. In plants, water evaporation through the stomata increases, which leads to a decrease in leaf temperature. In animals under these conditions, the evaporation of water through the respiratory system and skin also increases. In addition, poikilothermic animals avoid overheating through adaptive behavior: they choose habitats with the most favorable microclimate, hide in burrows or under stones during hot times of the day, are active at certain times of the day, etc.

Thus, environmental temperature is an important and often limiting factor in life manifestations.

Homeothermic animals - birds and mammals - are much less dependent on environmental temperature conditions. Aromorphic changes in structure allowed these two classes to remain active under very sharp temperature changes and colonize almost all habitats.

The depressing effect of low temperatures on organisms is enhanced by strong winds.

Light. Light in the form of solar radiation powers all life processes on Earth (Fig. 25.4). For organisms, the wavelength of the perceived radiation, its intensity and the duration of exposure (day length, or photoperiod) are important. Ultraviolet rays with wavelengths greater than 0.3 microns account for approximately 40% of the radiant energy reaching the earth's surface. In small doses they are necessary for animals and humans. Under their influence, vitamin D is formed in the body. Insects visually distinguish ultraviolet rays and use this to navigate the area in cloudy weather. Visible light with a wavelength of 0.4-0.75 microns has the greatest effect on the body. Visible light energy accounts for about 45% of the total radiant energy striking the Earth. Visible light is least attenuated when passing through dense clouds and water. Therefore, photosynthesis can occur in cloudy weather and under a layer of water of a certain thickness. But still, only 0.1 to 1% of incoming solar energy is spent on biomass synthesis.

Rice. 25.4.

Depending on the living conditions, plants adapt to the shade - shade-tolerant plants or, on the contrary, to the bright sun - light-loving plants. The last group includes cereals.

An extremely important role in regulating the activity of living organisms and their development is played by the duration of exposure to light - the photoperiod. In temperate zones, above and below the equator, the development cycle of plants and animals is confined to the seasons of the year and preparation for changing temperature conditions is carried out on the basis of a signal of day length, which, unlike other seasonal factors, is always the same at a certain time of the year in a given place. The photoperiod is like a trigger mechanism that sequentially includes physiological processes leading to growth and flowering of plants in the spring, fruiting in the summer and shedding of leaves in the fall, as well as molting and accumulation of fat, migration and reproduction in birds and mammals, and the onset of the resting stage in insects .

In addition to seasonal changes, the change of day and night determines the daily rhythm of activity of both entire organisms and physiological processes. The ability of organisms to sense time, the presence of a “biological clock” is an important adaptation that ensures the survival of an individual in given environmental conditions.

Infrared radiation accounts for 45% of the total amount of radiant energy falling on the Earth. Infrared rays increase the temperature of plant and animal tissues and are well absorbed by inanimate objects, including water.

For plant productivity, i.e. formation of organic matter, the most important indicator is the total direct solar radiation received over long periods of time (months, year).

Humidity. Water is a necessary component of the cell, so its quantity in certain habitats serves as a limiting factor for plants and animals and determines the nature of the flora and fauna in a given area. Excess water in the soil leads to the development of marsh vegetation. Depending on soil moisture (and annual precipitation), the species composition of plant communities changes. With annual precipitation of 250 mm or less, a desert landscape develops. The uneven distribution of precipitation across seasons also represents an important limiting factor for organisms. In this case, plants and animals have to endure long droughts. During a short period of high soil moisture, primary production for the community as a whole accumulates. It determines the size of the annual food supply for animals and saprophages (from the Greek. sapros- rotten and phagos - eater) - organisms that decompose organic remains.

In nature, as a rule, there are daily fluctuations in air humidity, which, along with light and temperature, regulate the activity of organisms. Humidity as an environmental factor is important because it modifies the effect of temperature. Temperature has a more pronounced effect on the body if the humidity is very high or low. Likewise, the role of humidity increases if temperatures are close to the species' tolerance limits. Species of plants and animals living in areas with insufficient moisture have, through the process of natural selection, effectively adapted to unfavorable arid conditions. Such plants have a powerfully developed root system, increased osmotic pressure of cell sap, which promotes water retention in tissues, a thickened leaf cuticle, and a greatly reduced leaf blade or turned into spines. In some plants (saxaul), leaves are lost, and photosynthesis is carried out by green stems. In the absence of water, the growth of desert plants stops, while moisture-loving plants wither and die in such conditions. Cacti are able to store large amounts of water in their tissues and use it sparingly. A similar adaptation was found in African desert milkweeds, which serves as an example of the parallel evolution of unrelated groups under similar environmental conditions.

Desert animals also have a range of physiological adaptations to cope with water shortages. Small animals - rodents, reptiles, arthropods - extract water from food. Fat, which accumulates in large quantities in some animals (the hump of a camel), also serves as a source of water. During the hot season, many animals (rodents, turtles) hibernate, lasting several months.

Ionizing radiation. Radiation with very high energy, which can lead to the formation of pairs of positive and negative ions, is called ionizing. Its source is radioactive substances contained in rocks; Moreover, it comes from space.

The intensity of ionizing radiation in the environment has increased significantly as a result of human use of atomic energy. Atomic weapons testing, nuclear power plants, their fuel production and waste disposal, medical research, and other peaceful uses of atomic energy create local “hot spots” and generate waste, often released into the environment during transportation or storage.

Of the three types of ionizing radiation that have important environmental significance, two are corpuscular radiation (alpha and beta particles), and the third is electromagnetic (gamma radiation and related x-rays).

Corpuscular radiation consists of a stream of atomic or subatomic particles that transfer their energy to whatever they encounter. Alpha radiation is helium nuclei; they are huge in size compared to other particles. The length of their run in the air is only a few centimeters. Beta radiation is fast electrons. Their dimensions are much smaller, the length of travel in the air is several meters, and in the tissues of an animal or plant organism - several centimeters. As for ionizing electromagnetic radiation, it is similar to light, only its wavelength is much shorter. It travels long distances in the air and easily penetrates matter, releasing its energy along a long trail. Gamma radiation, for example, easily penetrates living tissue; this radiation can pass through the body without having any effect, or it can cause ionization along a large portion of its path. Biologists often refer to radiation substances that emit alpha and beta radiation as “intrinsic emitters,” because they have their greatest effect when they are absorbed, ingested, or otherwise end up inside the body. Radioactive substances that emit predominantly gamma radiation are classified as “external emitters” because this penetrating radiation can have an effect when its source is outside the body.

Cosmic and ionizing radiation emitted by natural radioactive substances contained in water and soil form the so-called background radiation, to which existing animals and plants are adapted. In different parts of the biosphere, the natural background varies 3-4 times. Its lowest intensity is observed near the sea surface, and the highest at high altitudes in mountains formed by granite rocks. The intensity of cosmic radiation increases with altitude, and granite rocks contain more naturally occurring radionuclides than sedimentary rocks.

In general, ionizing radiation has the most destructive effect on more highly developed and complex organisms, and humans are especially sensitive.

Large doses received by the body over a short period of time (minutes or hours) are called acute doses, as opposed to chronic doses that the body would tolerate throughout its life cycle. The effects of low chronic doses are more difficult to measure as they may cause long-term genetic and somatic effects. Any increase in the level of radiation in the environment above the background, or even a high natural background, can increase the frequency of harmful mutations.

In higher plants, sensitivity to ionizing radiation is directly proportional to the size of the cell nucleus. In higher animals no such simple or direct relationship has been found between sensitivity and cell structure; For them, the sensitivity of individual organ systems is more important. Thus, mammals are very sensitive even to low doses due to the fact that rapidly dividing hematopoietic tissue, the bone marrow, is easily damaged by irradiation. The digestive tract is also sensitive, and damage to non-dividing nerve cells is observed only at high levels of radiation.

Once in the environment, radionuclides are dispersed and diluted, but they can accumulate in living organisms in various ways as they move through the food chain. Radioactive substances can also accumulate in water, soil, sediment, or air if the rate of release exceeds the rate of natural radioactive decay.

Pollutants. Human living conditions and the stability of natural biogeocenoses have been rapidly deteriorating over the past decades due to environmental pollution by substances generated as a result of human production activities. These substances can be divided into two groups: natural compounds, which are waste products from technological processes, and artificial compounds, which are not found in nature.

The first group includes sulfur dioxide (copper smelting), carbon dioxide (thermal power plants), oxides of nitrogen, carbon, hydrocarbons, compounds of copper, zinc and mercury, etc., mineral fertilizers (mainly nitrates and phosphates).

The second group includes artificial substances that have special properties that satisfy human needs: pesticides (from lat. pestis - infection, destruction and cido - kill), used to control animal pests of agricultural crops, antibiotics used in medicine and veterinary medicine to treat infectious diseases. Pesticides include insecticides (from Lat. insecta- insects and cido- kill) - means to combat harmful insects and herbicides (from lat. herba- grass, plant and cido- kill) - means to control weeds.

All of them have a certain toxicity (poisonous) to humans. At the same time, they serve as anthropogenic abiotic environmental factors that have a significant impact on the species composition of biogeocenoses. This influence is expressed in changes in soil properties (acidification, transition of toxic elements into a soluble state, disruption of the structure, depletion of its species composition); changes in water properties (increased mineralization, increased content of nitrates and phosphates, acidification, saturation with surfactants); changing the ratio of elements in soil and water, which leads to a deterioration in the development conditions of plants and animals.

Such changes serve as selection factors, as a result of which new plant and animal communities with a depleted species composition are formed.

Changes in environmental factors in terms of their effect on organisms can be: 1) regularly periodic, for example due to the time of day, season of the year or the rhythm of ebbs and flows in the ocean; 2) irregular, for example, changes in weather conditions in different years, disasters (storms, showers, landslides, etc.); 3) directed: during cooling or warming of the climate, overgrowing of water bodies, etc. Populations of organisms living in a particular environment adapt to this variability through natural selection. They develop certain morphological and physiological characteristics that allow them to exist in these and no other environmental conditions. For each factor influencing the body, there is a favorable force of influence, called the zone of optimum of the environmental factor or simply its optimum. For organisms of this species, deviation from the optimal intensity of the factor (decrease or increase) inhibits vital activity. The boundaries beyond which the death of the organism occurs are called the upper and lower limits of endurance (Fig. 25.5).

Rice. 25.5. Intensity of environmental factors

Anchor points

Most species of organisms are adapted to life in a narrow range of temperatures; Optimal temperature values range from +15 to +30 °C.
Light in the form of solar radiation powers all life processes on Earth.
Cosmic and ionizing radiation emitted by natural radioactive substances form “background” radiation to which existing plants and animals are adapted.
Pollutants, having a toxic effect on living organisms, impoverish the species composition of biocenoses.

Questions and tasks for review

1. What are abiotic environmental factors?
2. What adaptations do plants and animals have to changes in environmental temperature?
3. Indicate which part of the spectrum of visible radiation from the Sun is most actively absorbed by the chlorophyll of green plants?
4. Tell us about the adaptations of living organisms to a lack of water.
5. Describe the effect of various types of ionizing radiation on animal and plant organisms.
6. What is the influence of pollutants on the state of biogeocenoses?