Environmental factors. Environmental factors environmental conditions environmental factors Environmental factors of life

The environment is a set of living and nonliving objects, interrelated conditions and influences present in some environment of a living organism, and, in particular, a person.

The environment is divided into the following types:

a) natural or natural environment, represents a number of conditions or factors (sun, soil, water, air, flora and fauna);

b) artificial environment - created by man, the products of his labor (houses, parks, enterprises, highways, various mechanisms and machines);

c) the social environment is a team, family, friends.

The human body and any animal or plant develops as a result of constant exchange of matter and energy with the environment. Just as the environment influences living organisms, organisms influence the environment by changing it. This function of living organisms is called environment-forming.

Living organisms need an influx of matter and energy and are completely dependent on environment.

Environmental elements influence living organisms through environmental factors.

Environmental factors- these are certain conditions and elements of the environment that affect living organisms, to which the latter respond with adaptive reactions - adaptations.

Environmental factors conditions and resources are divided.

Conditions are factors necessary for life and which do not depend on their consumption (solar activity, water salinity, temperature, pressure).

Resources are what an organism can consume and thereby make them unavailable to other organisms; - everything from which the body draws energy and receives substances for its vital functions (oil, coal, etc.). Resources, unlike conditions, can be spent and exhausted.

Environmental factors are divided into

1) abiotic 2) biotic 3) anthropogenic

Abiotic- factors inanimate nature: climatic, soil, hydrological, chemical, physical.

Chemical ones include: gas composition of the atmosphere, water salinity, mineral composition of the soil; to physical – temperature, humidity, pressure, radiation level, etc.– factors of living nature, the influence of some organisms or communities on others, as well as on the habitat. Interactions between living organisms consist of intra- and interspecific relationships.

Intraspecific relationships between individuals of the same species. These relationships are reflected in competition for food, for habitat, and for a partner. Intraspecific relationships determine population size, which are regulated by natural selection.

Interspecies relationships are more diverse, among them the following are distinguished:

- neutralism– both types are independent and have no effect on each other. There is no competition, but one habitat (squirrel and elk in the same forest, monkeys and elephants);

-competition– each type has an adverse effect on the other;

- mutualism (symbiosis) - mutually beneficial existence, species cannot exist without each other (nitrogen-fixing bacteria and legumes; ungulates and bacteria living in their rumen that break down fiber);

- compensatoryism– one species, the compensation, benefits from cohabitation, and the other species, the owner, does not have any benefit (in the oceans and seas in each shell there are organisms that receive shelter here, but are absolutely harmless to the owner of this shell);

- predation– the predator feeds on the prey;

- amensalism– in this case, the growth of one species (amensal) is inhibited by the secretion product of another (blue-green algae, causing water blooms, thereby poison the aquatic fauna, and sometimes even livestock that comes to drink).

These relationships form the basis for the existence of biocenoses.

ANTHROPOGENIC - FACTORS human activity humans and its impact on the environment. Anthropogenic factors include the extraction and consumption of natural resources, fishing, construction of dams on rivers, impacts of industry, transport, construction, etc. Often the anthropogenic factor has a negative character, which consists in environmental pollution, destruction of the natural environment, and depletion of natural resources. V.I. Vernadsky compared the influence of the anthropogenic factor in strength with the effect of geological processes on Earth.

INFORMATION FACTOR– transfer of hereditary information, as well as information entering a living organism with food, water, as well as from the media for humans. Excess and lack of any information has an irritating effect not on the body (solitary confinement, without access to information - torture).

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 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 abiotic factors It is convenient to represent it as a combination of climatic, topographical, 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 ozone layer atmosphere.

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

Due to the rotation of the Earth, 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 natural ecosystems In 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 speed 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, while in an inactive state, have a body temperature not much higher than 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 different seasons, the diversity of species is less than in regions with more constant daily and annual temperatures.

Temperature, like light intensity, depends on latitude, season, time of day and slope exposure. 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 more dense, cold water 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 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 hot desert exist on Earth. a tropical forest. The difference is only in the annual amount of precipitation: in the first case, 0.2–200 mm, and in the second, 900–2000 mm.

Precipitation, closely related to air humidity, is the result of condensation and crystallization of water vapor in high layers of the atmosphere. Dew and fog form in the ground layer of air, and when low temperatures crystallization of moisture is observed - frost falls.

One of the main physiological functions of any organism is to maintain sufficient level amount 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, all life cycle which passes 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 water regime, pollution surface waters dangerous, and in some cases destructive for 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 relative homogeneity (homogeneity) of physical and chemical characteristics water bodies. average speed surface currents lie 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 minerals earth's crust, which 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 influence cosmic radiation In the atmosphere, new nuclei of radioactive atoms are constantly being formed, 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. Generally ionizing radiation has a more detrimental effect on highly developed and complex organisms, and humans are especially 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, comes close to comets, and gets hit cosmic dust, meteorite substances, 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- relations of representatives different types.

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- 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, 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 (EKS), 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, widely used in modern systems interactions 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, which in turn is polluted by motor vehicles and thermal power engineering, burial in ocean waters highly toxic chemical and radioactive substances, pollution from river runoff, disturbances in the water balance of coastal areas due to river regulation;

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 Earth's surface;

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 living things resources, how are they classified and what is their ecological significance?

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

These are any environmental factors to which the body reacts 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 acting directly or indirectly on the body - light, temperature, humidity, chemical composition air, water and soil environments, etc. (i.e., properties of the environment, the occurrence and impact of which do not directly depend on the activities 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, you can install general character 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. Extreme points curves expressing the state of oppression with a deficiency or excess of a factor are called areas of pessimum; 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 meanings salinity of the environment, 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. Stenobiontism or eurybiontism 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 geographical 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.

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 ecological 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 main role play:

• 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 character, 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 formed climatic conditions in turn, affect the community of forest-dwelling organisms.

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).

Name the entire set of factors inorganic environment affecting 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 environment natural environment(and hydrospheres, 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 aboutabout 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 increase, 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 greatest number 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 individual's ability to manage his cognitive abilities to survive unexpected changes in the environment is intelligence. The role of learning and intelligence in behavior increases with improvement nervous system- enlargement of 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 abundance 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. As a leading factor in different stages In the life of an organism, first one or another element of the environment may appear. 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 in different time years may vary.

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 effect on plant growth of the content of various chemical elements in the soil, he formulated the principle: “The substance found in the minimum controls the harvest 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 difficult 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.

Autoecology or factorial ecology studies the totality of environmental factors acting on an isolated individual, and the individual’s responses to their action.

Environmental factors are any components of the environment that directly or indirectly affect living organisms. Environmental factors are very diverse in their characteristics; they have different natures and specific actions. They are divided into three groups: abiotic (factors of the inanimate environment), biotic (related to the influence of living beings) and anthropogenic (related to human activity).

Abiotic factors- this is a set of conditions of the inorganic environment that in some way affect the organism and their communities. In ecology, they are considered as indispensable and important factors ensuring the life and development of plants, animals and microorganisms; they can influence organisms individually, simultaneously or interacting with each other. Abiotic factors include climatic, edaphic, topographical, hydrophysical and hydrochemical factors.

From climatic factors Temperature, humidity and light are of primary environmental importance, with the temperature factor being the most important. The intensity of metabolism of organisms and their geographical distribution depend on its value.

Among climatic factors, the radiant energy of the Sun is also of great importance - the main source of life on the planet.

The sun continuously emits a huge amount of radiant energy, the power of which at the upper limit of the atmosphere ranges from 8.4 to 84 J/cm 2 min (solar constant). As it approaches the Earth's surface, a significant portion of solar energy is retained by the atmosphere and vegetation.

The environmental effectiveness of radiant energy depends on the wavelength. Depending on the wavelength, within the entire light spectrum, visible light, ultraviolet and infrared parts are distinguished. Ultraviolet rays have a chemical effect on living organisms, while infrared rays have a thermal effect. Main

ecological significance

have: photoperiodism - a natural change of light and dark time of day; lighting intensity (in lux); voltage of direct and scattered radiation (in joules per unit surface and per unit time); chemical action of light energy.

The importance of light - the visible part (0.35 - 0.75 microns) of the spectrum of radiant energy, as an environmental factor, is associated with the possibility of photosynthesis of green plants and, ultimately, with the creation of organic matter, plant biomass, with the daily rhythm of organisms, etc. Environmental factors such as wind, atmospheric pressure, smog, etc. also have an impact

big influence on the biosphere in its entirety and under the combined influence of temperature and radiant energy. To edaphic factors refers to the entire set of physical and chemical properties of soils (structure, chemical composition, substances circulating in the soil - gas, water, organic and mineral elements, etc.).

All living organisms, depending on their need for water, and therefore according to their habitat, are divided into a number of ecological groups: aquatic or hydrophilic (live constantly in water), hygrophilic (live in very wet habitats), mesophilic (differing in moderate water needs ) and xerophilous (live in dry habitats). Each of the listed groups is a good indicator of the prevailing environmental conditions in a given area.

To biotic factors refer to the entire sum of the effects that living beings have on each other - bacteria, plants, animals. Biotic factors are not the abiotic environmental conditions modified by organisms (humidity, temperature, etc.) and not the organisms themselves, but the relationships between organisms, the direct effects of some of them on others, i.e. the nature of biotic factors is determined by the form of interrelations and relationships of living organisms.