The most important abiotic factors and the adaptation of living organisms to them

Characterize light as an abiotic factor. Give a classification of the ecological classes of plants in relation to light.

Describe temperature as an abiotic factor. Explain the environmental meaning of the Bergman and Allen rules (give examples).

  What is the difference between poikilothermic and homeothermic organisms?

  How is A. Hopkins bioclimatic law formulated? Give him an environmental explanation.

Describe humidity as an abiotic factor. Give examples of moisture- and dry-loving plants and animals, as well as those who prefer moderate humidity.

Among the main abiotic factors we consider shine, temperature  and humidity.

Shine.
   At one time, the French astronomer Camille Flammarion (1842-1925) wrote: "We don’t think about it, but everything that walks, moves, lives on our planet, is a child of the Sun." .

Indeed, it is only under the influence of light that the most important process of photosynthesis is carried out in the biosphere, which in general terms can be represented as follows:

Where A is the electron donor.

In green plants (higher plants and algae), the electron donor is water (oxygen), therefore, oxygen is formed as a result of photosynthesis:

In bacteria, the role of electron donor can be performed, for example, by hydrogen sulfide (sulfur), organic substances. So, in green and purple sulfur bacteria, the following process is going on:

With regard to light, organisms face a dilemma: on the one hand, the direct effect of light on a cell can be fatal for an organism, on the other hand, light serves as the primary source of energy, without which life is impossible.

Visible light has a mixed effect on organisms: red rays - thermal effects; blue and violet rays - change the speed and direction of biochemical reactions. In general, light affects the rate of growth and development of plants, the intensity of photosynthesis, the activity of animals, causes a change in humidity and ambient temperature, and is an important factor that ensures daily and seasonal biological cycles. Each habitat is characterized by a specific light regime determined byintensity (power), quantity and quality of light.

Intensity (Strength) light is measured by the energy per unit area per unit time: J / m2Chs; J / cm2hs. The relief features strongly influence this factor. Direct light is most intense, but diffused light is used more fully by plants.

Amount of light   determined by the total radiation. From the poles to the equator, the amount of light increases. To determine the light regime, it is necessary to take into account the amount of reflected light, the so-called albedo. Albedo (from lat. Albus - white) - the reflectivity of the surfaces of various bodies - is expressed as a percentage of the total radiation and depends on the angle of incidence of the rays and the properties of the reflecting surface. For example, the albedo of pure snow - 85%, contaminated - 40-50%, black soil - 5-14%, light sand - 35-45%, forest canopy - 10-18%, green maple leaves - 10%, yellowed autumn leaves - 28%.

In relation to light as an environmental factor, the following groups of plants are distinguished: heliophytes (from Greek helios - sun, phyton - plants), sciophytes (from Greek skia - shadow) and shade-tolerant plants (optional heliophytes).

Light plants (heliophytes)   - live in open areas with good lighting and are rarely found in the forest zone. The process of photosynthesis begins to prevail over the process of respiration only in high light conditions (wheat, pine, larch). The flowers of photophilous plants such as sunflower, goat breeder, and a succession turn behind the sun.

Shadow plants (sciophytes)   - they cannot stand strong lighting and live under a forest canopy in a constant shadow (these are mainly forest herbs, ferns, mosses, sour acid). In clearings under strong light, they show clear signs of oppression and often die.

Shade tolerant plants (optional heliophytes)  - They can live in good light, but they can easily tolerate dark places (most forest plants, meadow plants, forest herbs and shrubs).

Shade-tolerant tree species and shady herbaceous plants are distinguished by a mosaic arrangement of leaves. In eucalyptus leaves are turned to the light edge. In trees, light and shadow leaves (located respectively on the surface and inside the crown) - well-lit and shaded - have anatomical differences. Light leaves are thicker and coarser, sometimes they are shiny, which contributes to the reflection of light. Shadow leaves are usually opaque, undescended, thin, with or without very delicate cuticle (cuticle is the outer film covering the epidermis).

In the forest, shade-tolerant trees form densely closed stands. Under their canopy, even more shade-tolerant trees and shrubs grow, and below them are shadow shrubs and grasses. The figure shows two pine trees: one of them grew in open space with good lighting (1), and the other in a dense forest (2).

The most important light as a means of orientation is in the life of animals. The protozoa already have photosensitive organelles. So, euglena green with the help of a photosensitive “eye” reacts to the degree of illumination of the environment. Starting from the intestinal cavity, almost all animals develop photosensitive organs - eyes that have one or another structure.

Bioluminescence   called the ability of living organisms to glow. This occurs as a result of the oxidation of complex organic compounds with the participation of catalysts, usually in response to irritations from the external environment. The light signals emitted by fish, cephalopods, and other aquatic organisms, as well as by some organisms in the airborne environment (for example, beetles of the firefly family), serve to attract individuals of the opposite sex, lure prey or scare away predators, orientate in a pack, etc.

An important environmental factor is temperature.

Temperature.
   One of the most important factors determining the existence, development and spread of organisms around the globe is temperature. It is important not only the absolute amount of heat, but also its temporal distribution, i.e., the thermal regime.
   Plants do not have their own body temperature: their anatomical, morphological, and physiological mechanisms of thermo-
   regulation is aimed at protecting the body from the harmful effects of adverse temperatures.

In the zone of high temperatures at low humidity (tropical and subtropical deserts), a peculiar morphological type of plants with an insignificant leaf surface or with a complete absence of leaves has historically formed. Many desert plants form a whitish pubescence, which contributes to the reflection of sunlight and protects them from overheating (acacia sand, goose narrow-leaved).

The physiological adaptations of plants, smoothing out the harmful effects of high temperatures, can include: evaporation rate -transpiration    (from Lat. trans - through, spiro- I breathe, exhale), the accumulation of salts in the cells that change the coagulation temperature of the plasma, the property of chlorophyll to prevent the penetration of sunlight.

In the animal world, certain morphological adaptations are observed, aimed at protecting organisms from the adverse effects of temperatures. Evidence of this is the well-known bergman rule  (1847), according to which within a species or a fairly homogeneous group of related species, warm-blooded organisms with larger body sizes are common in colder regions.

We will try to explain this rule from the standpoint of thermodynamics: the loss of heat is proportional to the surface of the body, and not to its mass. The larger the animal and the more compact its body, the easier it is to maintain a constant temperature (lower specific energy consumption), and vice versa, the smaller the animal, the greater its relative surface and heat loss and the higher the specific level of its basic metabolism, i.e. the amount of energy spent the body of an animal (or human) with complete muscle rest at a temperature of the environment at which thermoregulation is most pronounced.

In animals with a constant body temperature in cold climatic zones, there is a tendency to a decrease in the area of \u200b\u200bthe protruding parts of the body (Allen rule, 1877).

Allen’s rule is clearly manifested, for example, when comparing the sizes of the ears of ecologically close species: the Arctic fox - an inhabitant of the tundra; common fox - typical of temperate latitudes; Fenech - an inhabitant of the deserts of Africa.
   The reaction of animals to the thermal regime is also manifested in changes in the proportions of individual organs and body (in the ermine from the northern regions, the heart, kidneys, liver and adrenal glands are enlarged compared with the same animals in areas with a higher temperature). There are exceptions to the Bergman and Allen rules.

Fenech

Depending on the type of heat transfer, two ecological types of animals are distinguished: poikilothermal and homoyothermal.

Poikilothermic organisms   (from Greek poikilos  - diverse) - animals with an unstable metabolic rate, an unstable body temperature and an almost complete absence of heat regulation mechanisms (cold-blooded). These include invertebrates, fish, reptiles, amphibians, i.e., most animals, with the exception of birds and mammals.

Their body temperature changes with a change in ambient temperature.

Homoyothermal organisms (from Greek homoios  - the same) - animals with a higher and more stable metabolic rate, during which thermoregulation is carried out and a relatively constant body temperature (warm-blooded) is ensured. These include birds and mammals. Body temperature is maintained at a relatively constant level.

In turn, poikilothermic animals can be divided into eurythermic, leading an active lifestyle in a relatively wide temperature range, and stenothermic, not tolerating significant temperature fluctuations.

Thermoregulation mechanisms are chemical and physical.

The chemical mechanism is due to the intensity of reactions in the body and is carried out in a reflex way:

The physical mechanism of thermoregulation is provided by heat-insulating integuments (fur, feathers, fat layer), the activity of sweat glands, evaporation of moisture during breathing, and vascular regulation of blood circulation.

In poikilothermic animals, the metabolic rate is directly proportional to external temperature, in homoothermic animals, on the contrary, when it decreases, heat loss increases and metabolic processes are activated in response, and heat production increases. The intensity of metabolism (metabolic processes) in homeothermia is inversely proportional to external temperatures. However, such a pattern can be traced only within certain limits. Raising or lowering the temperature relative to the threshold value causes overheating or hypothermia of the animal and, as a result, its death.

An intermediate position between poikilothermic and homeothermic is occupied by heterothermal animals. In their active state, a relatively high and constant body temperature is maintained, and in the inactive state, the body temperature differs little from the external. In these animals, during hibernation or deep sleep, the level of metabolism decreases, and the body temperature only slightly exceeds the temperature of the environment. Typical representatives of heterothermal animals are ground squirrels, hedgehogs, bats, bears, swifts, platypuses, echidna, kangaroos.

Consider the example of insects, representatives of poikilothermic animals (see. Figure).

Curve P.I. Bakhmetev

At t ° + 10 ° C, insects become numb, at t ° 0 ° C - hypothermia. It continues until the crystallization of water, which is accompanied by a temperature jump. After a sharp increase in it, processes begin leading to a deterioration in the physiological state of the body. The physiological state of the insect during cooling depends on the rate of temperature decrease. With slow cooling, ice crystals form in the cells, which break their shell. With very rapid cooling, the crystallization centers do not have time to form, and a vitreous structure is formed. As a result, the cytoplasm is not damaged. Thus, deep, but very rapid cooling causes a temporary, reversible suspension of all vital processes of the body. A similar condition, called suspended animation, is observed in viruses, bacteria, invertebrates, amphibians, reptiles, lichens, mosses. The phenomenon of suspended animation was first discovered and described by A. Levenguk (1701).

The study of suspended animation was the impetus for the development of various cryotechnology   (from Greek kryos- cold, frost), for example, cryopreservation. This method is widely used in biology, medicine, agriculture, in the practice of long-term storage of canned blood, sperm for artificial insemination of farm animals, various tissues and organs for transplantation (from Latin transplantatio - transplantation), cultures, bacteria, viruses.

The temperature factor is important in the distribution of living organisms on Earth and thereby determines their population of different natural zones. In 1918, A. Hopkins formrevealed bioclimatic law . He established that there is a natural, close connection between the development of phenological (seasonal) phenomena and the latitude, longitude and altitude of the area above sea level.
   He calculated thatas you move north, east and into the mountains, the onset of periodic phenomena in the life of organisms is 4 days late for each degree of latitude, 5 degrees of longitude, and about 100 m in height.

One of the important patterns in the distribution of modern organisms is their bipolarity - the geographical distribution of terrestrial and marine flora and fauna, in which the same species lives in the cold and temperate latitudes of both hemispheres, but is absent in the tropical belt (toothless whales, eared seals, etc. .).

An equally important environmental factor is humidity.

Humidity.
   Water is the most important environmental factor in the life of living organisms and their constant component. All living things on Earth include water, for example, jellyfish contain 95-99% of water, corn 70%, cereals 87%. Even in a barn weevil eating a dry grain, 46% of the water is contained. In the human embryo, 97% of water, after his birth - 64-77%. In men aged 18 to 50 years, the body contains ~ 61% of water, in women 54%.

During his life, a person drinks up to 50-77 m3 of water (per day ~ 2.5-3 l). In general, a person loses 2-2.5 liters of water per day: 800-

1300 ml with urine, about 200 ml with feces and 600 ml from the surface of the body and when breathing. With the loss of 1-1.5 liters of water, a person becomes thirsty, at the expense of 6-8% of moisture from body weight, he falls into a fainting state, with a deficit of 10-12%, death occurs.

In different periods of development, the need of plants for water varies, especially in different species; it also varies with climate and soil type. For example, cereals during the period of seed germination and ripening need less moisture than during their intensive growth. For each phase of growth and stage of development of any type of plant, a critical period can be distinguished when a lack of water has a particularly negative effect on its life. Humidity is often a factor limiting the number and distribution of organisms around the globe. For example, beech can live on relatively dry soil, but it needs a fairly high humidity. In animals, the permeability of the integument and the mechanisms that regulate water exchange play a very important role.

There are absolute air humidity, which is the amount of gaseous water (steam) in grams per 1 m3 of air, and relative. Relative humidity characterizes the degree of saturation of air with water vapor at a certain temperature and is expressed as a percentage as the ratio of absolute humidity to maximum humidity (mass of water vapor in grams that can create full saturation in 1 m3 of air)

where: r is the relative humidity,%;
   m is the mass of steam actually contained in 1 m3 of air (absolute humidity), g;
   mnas - mass of 1 m3 of saturated steam at a given temperature, g.

Important for organisms is the deficiency of air saturation with water vapor, i.e. the difference between the maximum and absolute humidity at a given temperature:

d \u003d mnas - m.

At different temperatures, the deficiency of air saturation with water vapor varies with the same humidity. The higher the temperature, the drier the air, and the more intense transpiration occurs in it (evaporation of water by leaves and other parts of plants).

The seasonal distribution of moisture throughout the year, as well as its daily fluctuation, is also extremely important for the life of organisms.

In relation to the water regime, the following ecological groups of plants and animals are distinguished: moisture-loving, dry-loving and preferring moderate humidity. Among the plants are distinguished:

Among terrestrial animals distinguish:

Hydrophiles   - hygrophilous animals (wood lice, springtails, mosquitoes, terrestrial planarians, terrestrial mollusks and amphibians).

Mesophiles   - live in areas with moderate humidity (winter scoop, many insects, birds, mammals).

Xerophiles   are dry-loving animals that cannot tolerate high humidity (camels, desert rodents and reptiles).

For example, an elephant tortoise stores water in the bladder, some mammals avoid moisture deficiency by the deposition of fats, which oxidize to form metabolic water. Due to metabolic water, many insects, camels, fat tail sheep, fat-tailed jerboas, and others live.

Constantly evolving, mankind does not particularly think about how abiotic factors directly or indirectly affect a person. What are abiotic conditions and why their seemingly imperceptible influence is so important to consider? These are certain physical phenomena that are not related to living nature, which in one way or another affect the life or environment of a person. Roughly speaking, light, the degree of humidity, the Earth’s magnetic field, temperature, and the air we breathe are all called abiotic parameters. Under this definition, the influence of living organisms, including bacteria, microorganisms and even protozoa, does not fall in any way.

Quick article navigation

Examples and types

We have already found out that this is a combination of phenomena of inanimate nature, which can be climatic, water or soil. The classification of abiotic factors is conditionally divided into three types:

1. Chemical
2. Physical
3. Mechanical.

The chemical effect is exerted by the organic and mineral composition of the soil, atmospheric air, groundwater and other waters. The physical ones include natural lighting, pressure, temperature and humidity of the environment. Accordingly, cyclones, solar activity, soil, air and water movement in nature are considered mechanical factors. The combination of all these parameters has a tremendous impact on the reproduction, distribution and quality of life of all living things on our planet. And if a modern person thinks that all these phenomena, literally controlling the life of his ancient ancestors, have now been tamed with the help of progressive technologies, then, unfortunately, this is not so at all.

It is impossible to overlook the biotic factors and processes that are inevitably tied to the abiotic effect on all living things. Biotic are called the forms of influence of living organisms on each other, almost any of them is caused by abiotic environmental factors and their effect on living organisms.

What influence can factors of inanimate nature have?

To begin with, you need to identify what abiotic environmental factors come under the definition of? Which of the parameters can be attributed here? The abiotic environmental factors include: light, temperature, humidity, atmosphere. Consider what factor exactly affects in more detail.

Shine

Light is one of the environmental factors that literally every object uses in geobotany. Sunlight is the most important source of thermal energy, responsible in nature for the processes of development, growth, photosynthesis, and many, many others.

Light, as an abiotic factor, has a number of specific characteristics: spectral composition, intensity, periodicity. The most important are these abiotic conditions for plants whose main life is the process of photosynthesis. Without a high-quality spectrum and good lighting intensity, the plant world will not be able to actively reproduce and grow fully. The duration of the light exposure is also important, so, with a short daylight, the growth of plants is significantly reduced, the reproduction functions are inhibited. Not in vain for good growth and harvesting, in greenhouse (artificial) conditions, they necessarily create the maximum possible light period for the duration, so necessary for plant life. In such cases, natural biological rhythms are cardinally and intentionally disrupted. Lighting is the most important natural factor for our planet.

Temperature

Temperature is also one of the most powerful among abiotic factors. Without the right temperature, life on Earth is really impossible - and this is not an exaggeration. Moreover, if a person can deliberately maintain the light balance at a certain level, and this is quite simple, the situation with temperature is much more difficult.

  Of course, over millions of years of existence on the Planet, both plants and animals have adapted to their uncomfortable temperature. Thermoregulation processes are different here. For example, two methods are distinguished in plants: physiological, namely, an increase in the concentration of cell sap due to the intense accumulation of sugar in cells. Such a process provides the necessary level of frost resistance of plants at which they may not die even at very low temperatures. The second method is physical, it consists in the special structure of the foliage or its reduction, as well as growth methods - squat or creeping on the ground - to avoid freezing in open space.

Among animals there are eurythermic ones - those that freely exist with significant temperature fluctuations, and stenothermic ones, for which a certain temperature range of not too large size is important. Eurythermic organisms exist when the ambient temperature fluctuates within 40-50 degrees, usually these are conditions close to the continental climate. In summer, high temperatures, in winter - frost.

A vivid example of a eurythermic animal can be considered a hare. In the warm season, he feels comfortable in the heat, and in cold weather, turning into a white, he perfectly adapts to the temperature abiotic environmental factors and their effect on living organisms.

There are many representatives of the fauna - these are animals, insects, and mammals, which have another type of thermoregulation - with the help of a state of stupor. In this case, the metabolism slows down, but the body temperature can be maintained at the same level. Example: for a brown bear, the winter temperature is the abiotic factor, and its method of adaptation to frost is winter hibernation.

Air

Abiotic environmental factors also include air. In the process of evolution, living organisms had to master the air habitat after leaving the water on land. Some of them, especially this was reflected in insects and birds, in the process of developing species moving on the ground, adapted to movement through the air, having mastered the technique of flight.

The process of anschmochoria — the migration of plant species by means of air currents — should not be ruled out - the vast majority of plants populated the territories in which they now grow, by pollination, transfer of seeds by birds, insects, and the like.

If you ask what abiotic factors affect the flora and fauna, then the atmosphere, in terms of its influence, will obviously not be in last place - its role in the process of evolution, development and population size cannot be exaggerated.

However, it is not air itself that matters, as a parameter that affects nature and organisms, but its quality, namely, its chemical composition. What factors are important in this aspect? There are two of them: oxygen and carbon dioxide.

Oxygen value

Without oxygen, only anaerobic bacteria can exist; it is extremely necessary for other living organisms. The oxygen component of the air environment refers to those types of products that are only consumed, but only green plants can produce oxygen by the method of photosynthesis.

Oxygen entering the body of a mammal is bound into a chemical compound by hemoglobin of blood and, in this form, is transported with blood through all cells and organs. This process ensures the normal functioning of any living organism. The influence of the air on the process of life support is great and continuous throughout life.

The value of carbon dioxide

Carbon dioxide is a product exhaled by mammals and some plants, and it is also formed during the combustion and vital activity of soil microorganisms. However, all these natural processes emit how insignificant amounts of carbon dioxide that they cannot even be compared with the real disaster of the ecosystem, which has a direct and indirect relation to all natural processes - industrial emissions and products from technological processes. And, if only some hundred years ago, a similar problem would mainly have been observed in a large industrial city, such as, for example, Chelyabinsk, then today, it is spread almost throughout the entire planet. Nowadays, carbon dioxide, produced everywhere: by enterprises, vehicles, various devices, is steadily expanding its exposure group, including the atmosphere.

Humidity

Humidity, as an abiotic factor, is the water content, in anything: plant, air, soil or a living organism. From environmental factors, it is humidity that is the first condition necessary for the origin and development of life on Earth.

Absolutely everything living on the planet needs water. The mere fact that any living cell is eighty percent water consists speaks for itself. And for many living creatures, it is water bodies or a humid climate that are ideal living conditions for the natural environment.

  The wettest place on the land of Urek (Bioko Island, Equatorial Guinea)

Of course, there are types of terrain where the amount of water is minimal or is present at any frequency, such as desert, alpine terrain, and the like. This has an obvious effect on nature: the absence or minimum of vegetation, drying out soil, no fruiting plants, only those types of flora and fauna that can adapt to similar conditions survive. Adaptation, to whatever extent it is expressed, is not lifelong and, in the case when the characteristics of abiotic factors change for some reason, it can also change or disappear altogether.

In the degree of influence on nature, humidity, it is important to consider not only as a single parameter, but also in combination with each of the listed factors, since together they form the type of climate. Each particular territory with its abiotic environmental factors, has its own characteristics, vegetation, species and population size.

The effect of abiotic factors on humans

Man, as a component of the ecosystem, likewise refers to objects that are influenced by abiotic factors of inanimate nature. The dependence of human health and behavior on solar activity, the lunar cycle, cyclones, and the like, was noted several centuries ago, thanks to the observation of our ancestors. And in modern society, the presence of a group of people is invariably fixed, on the mood and well-being changes of which abiotic environmental factors have an indirect effect.

For example, studies of solar influence have shown that this star has an eleven-year cycle of periodic activity. On this soil, the electromagnetic field of the Earth fluctuates, which is what affects the human body. Peaks in solar activity can weaken the immune system, and pathogenic microorganisms, on the contrary, make them more tenacious and adapted to widespread distribution within the community. The sad consequences of this process are outbreaks of epidemics, the emergence of new mutations and viruses.

  Unknown infection epidemic in India

Another important example of abiotic influence is ultraviolet. Everyone knows that in certain doses, this type of radiation is even useful. This environmental factor has an antibacterial effect, slows down the development of spores that cause skin diseases. But in large doses, ultraviolet radiation negatively affects the population, causing deadly diseases such as cancer, leukemia or sarcoma.

The manifestations of the action of abiotic environmental factors on humans directly include temperature, pressure and humidity, in short - climate. An increase in temperature will lead to inhibition of physical activity and the development of problems with the cardiovascular system. Low temperatures are dangerous by hypothermia, which means inflammation of the respiratory system, joints and limbs. It should be noted here that the humidity parameter further enhances the influence of the temperature regime.

Increased atmospheric pressure threatens the health of owners of weak joints and fragile vessels. Especially dangerous, there are sharp changes in this climatic parameter - sudden hypoxia, clogging of capillaries, fainting, and even coma can occur.

Of the environmental factors, one cannot but note the chemical aspect of human influence. These include all chemical elements contained in water, atmosphere or soil. There is a concept of regional factors - the excess or, on the contrary, the lack of certain compounds or trace elements in the nature of each individual region. For example, of the listed factors, both the lack of fluorine is harmful - it causes damage to tooth enamel, and its overabundance - speeds up the process of ossification of ligaments, disrupts the functioning of some internal organs. The fluctuations in the content of such chemical elements as chromium, calcium, iodine, zinc, and lead are especially noticeable in the incidence of the population.

Of course, many abiotic conditions, of the above, although they are abiotic factors of the natural environment, in fact are very much dependent on human life - the development of mines and deposits, changes in river beds, air environment, and the like examples of the intervention of progress in natural phenomena.

Detailed description of abiotic factors

Why is the effect on the population of most abiotic factors so huge? This is logical: because to ensure the life cycle of any living organism on Earth, the totality of all parameters that affect the quality of life, its duration, which determines the number of ecosystem objects, is important. Lighting, atmospheric composition, humidity, temperature, zonation of wildlife, salinity of water and air, its edaphic data are the most important abiotic factors and adaptation of organisms to them is positive or negative, but in any case, it is inevitable. This is easy to make sure: just look around!

Abiotic factors of the aquatic environment provide the origin of life, make up three quarters of every living cell on Earth. In the forest ecosystem, all the same parameters belong to biotic factors: humidity, temperature, soil, light - they determine the type of forest, saturation with plants, and their adaptability to a particular region.

In addition to the obvious, already listed, important abiotic factors of the environment should also be called salinity, soil and the electromagnetic field of the Earth. The entire ecosystem has evolved over hundreds of years, the terrain has been modified, the degree of adaptability of living organisms to various living conditions, new species have appeared and entire populations have migrated. However, this natural chain has long been broken by the fruits of human life on the planet. The work of environmental factors is fundamentally disrupted due to the fact that the impact of abiotic parameters does not occur purposefully, like inanimate factors, but already as a harmful effect on the development of organisms.

Unfortunately, the influence of abiotic factors on the quality and life expectancy of a person and humanity as a whole has been and remains enormous and can have both positive and negative consequences for each individual organism for all of humanity as a whole.

Abiotic, biotic and anthropogenic environmental factors

The natural environment of a living organism is composed of many inorganic and organic components, including those introduced by humans. However, some of them may be necessary for organisms, others do not play a significant role in their life. So, for example, a hare, a wolf, a fox and any other animal in the forest are interconnected with a huge number of elements. Without such as air, water, food, a certain temperature, they cannot do. Others, for example, a boulder, a tree trunk, a stump, a hummock, a groove, are environmental elements to which they may be indifferent. Animals enter into temporary (shelter, crossing) with them, but not mandatory relationships.

The environmental components that are inevitably confronted with an organism’s life are called environmental factors.

Environmental factors may be necessary or harmful to living things, promote or inhibit survival and reproduction.

Living conditions are a set of environmental factors that determine the growth, development, survival and reproduction of organisms.

The whole variety of environmental factors is usually divided into three groups: abiotic, biotic and man-made.

Abiotic factors  - This is a combination of the properties of inanimate nature important for organisms. These factors, in turn, can be divided. on chemical  (composition of the atmosphere, water, soil) and physical(temperature, pressure, humidity, currents, etc.). A variety of terrain, geological and climatic conditions give rise to a huge variety of abiotic factors.

Of primary importance are climatic  (sunlight, temperature, humidity); geographic(duration of day and night, topography); hydrological(gr. hydor-water) - flow, excitement, composition and properties of water; edaphic(gr. edaphos - soil) - composition and properties of soils, etc.

All factors can affect organisms. directly or indirectly. For example, the terrain affects lighting conditions, humidity, wind and microclimate.

Biotic factors  - this is a combination of the effects of the vital activity of some organisms on others. For each organism, all the others are important environmental factors; they have no less effect on it than inanimate nature. These factors are also very diverse.

The whole variety of relationships between organisms can be divided into two main types: antagonistic  (gr. antagonizsma - struggle) and non-antagonistic.

Predation  - a form of relationships between organisms of different trophic levels, in which one species of organisms lives at the expense of another, eating it (+ -)

(Fig. 5.1). Predators can specialize in one prey (lynx is a hare) or be multinivorous (wolf). In any biocenosis, evolutionary mechanisms have been formed that regulate the numbers of both the predator and the prey. Unreasonable destruction of predators often leads to a decrease in their viability

Figure 5.1 - predation

Competition(lat concurrentia - rivalry) - a form of relationship in which organisms of the same trophic level fight for food and other conditions of existence, crushing each other (- -). Competition is evident in plants. Trees in the forest tend to cover as much space as possible with their roots in order to receive water and nutrients. They also stretch in height to the light, seeking to overtake their competitors. Weed grasses clog other plants (Figure 5.3). Many examples from the life of animals. Intense competition explains, for example, the incompatibility of wide-crawled and narrow-toed crayfish in one pond: usually narrow-crayfish wins, as it is more fertile.

Figure 5.3-Competition

The greater the similarity in the requirements of the two species to living conditions, the stronger the competition, which can lead to the disappearance of one of them. The type of interactions of specific species may vary depending on the conditions or stages of the life cycle.

Antagonistic relationships are more pronounced in the initial stages of community development. In the process of ecosystem development, there is a tendency to replace negative interactions with positive ones that increase the survival of species.

Non-antagonisticrelationships can theoretically be expressed in many combinations: neutral (0 0), mutually beneficial (+ +), one-sided (0 +), etc. The main forms of these interactions are as follows: symbiosis, mutualism, and commensalism.

Symbiosis  (gr. symbiosis - cohabitation) - these are mutually beneficial, but not mandatory, relationships between different types of organisms (+ +). An example of symbiosis is the cohabitation of hermit crab and sea anemone: sea anemone moves by attaching to the back of the cancer, and it receives richer food and protection with the help of sea anemone (Fig. 5.4).

Figure 5.4 - Symbiosis

Sometimes the term "symbiosis" is used in a broader sense - "live together."

Mutualism  (lat. mutuus - mutual) - mutually beneficial and mandatory for growth and survival relations of organisms of different species (+ +). Lichens are a good example of the positive relationship of algae and fungi. When insects spread plant pollen in both species, specific adaptations are developed: color and smell in plants, proboscis in insects, etc.

Figure 5.5 - Mutualism

Commensalism(lat. commensa / is - companion) - a relationship in which one of the partners benefits, and the other they are indifferent (+ 0). Commensalism is often observed at sea: in almost every mollusk shell, in the body of the sponge there are “uninvited guests” using them as shelters. Birds and animals that feed on leftovers from predators are examples of commensals (Fig. 5.6).

Figure 5.6- Commensalism

Despite competition and other types of antagonistic relationships, in nature, many species can coexist quietly  (Fig. 5.7). In such cases, it is said that each species has own ecological niche  (fr. niche - nest). The term was proposed in 1910 by R. Johnson.

Closely related organisms that have similar environmental requirements do not live, as a rule, under the same conditions. If they live in one place, they either use different resources, or have other differences in functions.

For example, different types of woodpeckers. Although they all equally feed on insects and nest in tree hollows, they have, as it were, different specializations. A large motley woodpecker produces food in tree trunks, a medium variegated one in large upper branches, a small variegated one in thin branches, a green woodpecker preys on ants on the ground, and a three-fingered woodpecker searches for dead and charred tree trunks, i.e. different types of woodpeckers have different ecological niches.

An ecological niche is a combination of territorial and functional characteristics of the environment that meet the requirements of a given species: food, breeding conditions, relations with competitors, etc.

Some authors use the terms “habitat” or “habitat” instead of the term “ecological niche”. The latter include only habitat, and the ecological niche, in addition, determines the function that the species performs. P. Agess (1982) provides such definitions of a niche and environment: environment - the address at which the organism lives, and a niche is his profession  (Fig. 5.7).

Figure 5.7 - Peaceful coexistence of different organisms

Figure 5.8 - Environmental Niches

Anthropogenic factors- this is a combination of various human influences on inanimate and living nature. With the historical development of mankind, nature has been enriched by qualitatively new phenomena. Only by their physical existence do people exert a noticeable influence on the environment: in the process of breathing, they annually emit 1 * 10 12 kg of CO 2,  and they consume with food about 5 * 10 15 kcal.  To a much greater extent, the biosphere is affected by the production activities of people. As a result of it, the relief and composition of the earth’s surface, the chemical composition of the atmosphere, climate change, fresh water is redistributed, natural ecosystems disappear and artificial agro-and techno-ecosystems are created, cultivated plants are cultivated, animals are domesticated, etc.

Human exposure can be direct and indirect. For example, deforestation and uprooting of the forest not only have a direct effect (the destruction of trees and shrubs), but also indirectly — the conditions for the existence of birds and animals change. It is estimated that since 1600, 162 species of birds and over 100 species of mammals have been destroyed in one way or another. But, on the other hand, it creates new varieties of plants and animal breeds, constantly increasing their productivity and productivity. Artificial resettlement of plants and animals also has a great impact on the life of ecosystems. Thus, rabbits brought to Australia multiplied there so much that they caused enormous damage to agriculture.

The rapid urbanization (lat. Urbanus - urban) - the growth of cities over the past half century - has changed the face of the Earth more than many other activities in the history of mankind. The most obvious manifestation of anthropogenic impact on the biosphere is environmental pollution.

ecological environment organism population abundance

Living conditions (conditions of existence) are a set of elements necessary for an organism with which it is inextricably linked and without which it cannot exist.

Adaptation of the body to the environment is called adaptation. The ability to adapt is one of the main properties of life in general, providing the possibility of its existence, survival and reproduction. Adaptation is manifested at different levels - from cell biochemistry and the behavior of individual organisms to the structure and functioning of communities and ecosystems. Adaptations arise and change during the evolution of the species.

Individual properties or elements of the environment that affect organisms are called environmental factors. Environmental factors are diverse. They have a different nature and specificity of action. Environmental factors are divided into two large groups: abiotic and biotic.

Abiotic factors are a set of inorganic environment conditions that affect living organisms directly or indirectly: temperature, light, radiation, pressure, air humidity, salt composition of water, etc.

Biotic factors are all forms of the influence of living organisms on each other. Each organism constantly experiences the direct or indirect influence of others, entering into a relationship with representatives of its own and other species.

In some cases, anthropogenic factors are distinguished as an independent group along with biotic and abiotic factors, emphasizing the extreme effect of the anthropogenic factor.

Anthropogenic factors are all forms of human society that lead to a change in nature as the habitat of other species or directly affect their lives. The value of anthropogenic impact on the entire living world of the Earth continues to grow rapidly.

Changes in environmental factors over time can be:

• 1) regularly constant, changing the strength of the impact in connection with the time of day, season of the year or the rhythm of the tides in the ocean;
• 2) irregular, without a clear periodicity, for example, changes in weather conditions in different years, storms, downpours, mudflows, etc .;
• 3) directed for certain or long periods of time, for example, cooling or warming of the climate, overgrowing of a reservoir, etc.

Environmental environmental factors can have various effects on living organisms:

• 1) as irritants, causing adaptive changes in physiological and biochemical functions;
• 2) as limiters that make it impossible to exist in these conditions;
• 3) as modifiers causing anatomical and morphological changes in organisms;
• 4) as signals indicating a change in other factors. \u003d

Despite the wide variety of environmental factors, a number of general patterns can be distinguished in the nature of their interaction with organisms and in the responses of living things.

The intensity of the environmental factor, the most favorable for the life of the body, is the optimum, and giving the worst effect is the pessimum, i.e. conditions under which the vital activity of the organism is inhibited as much as possible, but it can still exist. So, when growing plants in various temperature conditions, the point at which maximum growth is observed will be the optimum. In most cases, this is a certain temperature range of several degrees, so here it is better to talk about the optimum zone. The entire temperature range (from minimum to maximum), at which growth is still possible, is called the range of stability (endurance), or tolerance. The point limiting it (i.e., the minimum and maximum) suitable for life temperatures is the limit of stability. Between the optimum zone and the limit of resistance, as one approaches the latter, the plant experiences increasing stress, i.e. we are talking about stress zones, or zones of oppression, within the range of stability

As you move up and down on the scale, stress not only intensifies, but ultimately, upon reaching the limits of stability of the body, its death occurs. Similar experiments can be carried out to check the influence of other factors. The results will graphically correspond to a curve of this type.

Ground-air environment of life, its characteristics and forms of adaptation to it

Life on land required such adaptations that were possible only with highly organized living organisms. Ground-air environment is more difficult for life, it is characterized by a high oxygen content, a small amount of water vapor, low density, etc. This greatly changed the conditions of respiration, water exchange and movement of living things.

Low air density determines its low lift and low bearing capacity. Air organisms should have their own support system that supports the body: plants - a variety of mechanical tissues, animals - a solid or hydrostatic skeleton. In addition, all inhabitants of the air environment are closely connected with the surface of the earth, which serves as their attachment and support.

Low air density provides low resistance to movement. Therefore, many land animals have acquired the ability to fly. 75% of all terrestrial ones, mainly insects and birds, adapted to active flight.

Due to the mobility of the air, the vertical and horizontal streams of air masses existing in the lower atmosphere are possible passive flight of organisms. In this regard, many species have developed anemochoria - resettlement using air currents. Anemochoria is characteristic of spores, seeds and fruits of plants, protozoa cysts, small insects, spiders, etc. Organisms passively carried by air currents are collectively called aeroplankton.

Terrestrial organisms exist under relatively low pressure, due to the low density of air. Normally, it is equal to 760 mmHg. With increasing altitude, the pressure decreases. Low pressure can limit the prevalence of species in the mountains. For vertebrates, the upper limit of life is about 60 mm. A decrease in pressure entails a decrease in oxygen supply and dehydration of animals by increasing the respiratory rate. About the same limits of advancement in the mountains are higher plants. Arthropods, which can be found on glaciers, are somewhat more hardy, above the border of vegetation.

The gas composition of the air. In addition to the physical properties of the air, its chemical properties are very important for the existence of terrestrial organisms. The gas composition of the air in the surface layer of the atmosphere is quite uniform with respect to the content of the main components (nitrogen - 78.1%, oxygen - 21.0%, argon - 0.9%, carbon dioxide - 0.003% of the volume).

The high oxygen content contributed to an increase in metabolism in terrestrial organisms compared with primary aquatic organisms. It was in a terrestrial environment, on the basis of the high efficiency of oxidative processes in the body, that the animal homeothermia arose. Due to its constant high content in air, oxygen is not a limiting factor in life in the terrestrial environment.

The carbon dioxide content can vary in certain areas of the surface layer of air in a fairly significant range. Increased air saturation WITH? occurs in zones of volcanic activity, near thermal springs and other underground outlets of this gas. In high concentrations, carbon dioxide is toxic. In nature, such concentrations are rare. Low CO2 content inhibits photosynthesis. In a closed environment, you can increase the rate of photosynthesis by increasing the concentration of carbon dioxide. This is used in the practice of greenhouse and greenhouse farming.

For most inhabitants of the terrestrial environment, air nitrogen is an inert gas, but individual microorganisms (nodule bacteria, nitrogen bacteria, blue-green algae, etc.) have the ability to bind it and involve them in the biological cycle of substances.

Moisture deficiency is one of the essential features of the airborne living environment. The entire evolution of terrestrial organisms went under the sign of adaptation to the production and preservation of moisture. Modes of humidity on land are very diverse - from the complete and constant saturation of air with water vapor in some areas of the tropics to their almost complete absence in the dry desert air. The daily and seasonal variability of the water vapor content in the atmosphere is also significant. The water availability of terrestrial organisms also depends on the mode of precipitation, the presence of ponds, soil moisture reserves, the proximity of pound water, etc.

This led to the development in terrestrial organisms of adaptation to various modes of water supply.

Temperature mode. The next distinguishing feature of the air-ground environment is significant temperature fluctuations. In most land areas, daily and annual temperature amplitudes are tens of degrees. Resistance to temperature changes in the environment of terrestrial inhabitants is very different, depending on in which specific habitat their life passes. However, in general, terrestrial organisms are much more eurythermic compared to aquatic organisms.

Living conditions in the airborne environment are complicated, in addition, by the existence of weather changes. Weather - continuously changing atmospheric conditions at the borrowed surface, up to an altitude of about 20 km (the boundary of the troposphere). Weather variability is manifested in the constant variation of a combination of environmental factors such as temperature, air humidity, cloud cover, precipitation, wind strength and direction, etc. Long-term weather conditions characterize the climate of the area. The concept of “Climate” includes not only the average values \u200b\u200bof meteorological phenomena, but also their annual and daily course, deviation from it and their frequency. The climate is determined by the geographical conditions of the area. The main climatic factors - temperature and humidity - are measured by rainfall and air saturation with water vapor.

For most terrestrial organisms, especially small ones, the region’s climate is not so important as the conditions of their direct habitat. Very often, local elements of the environment (relief, exposure, vegetation, etc.) change the regime of temperature, humidity, light, air movement in a particular area so that it differs significantly from the climatic conditions of the area. Such climate modifications, developing in the surface layer of air, are called microclimate. In each zone, the microclimate is very diverse. Microclimates of very small areas can be distinguished.

The light mode of the air-ground environment also has some features. The intensity and amount of light here are the greatest and practically do not limit the life of green plants, as in water or soil. On land, extremely photophilous species may exist. For the vast majority of terrestrial animals with day and even night activity, vision is one of the main ways of orientation. In terrestrial animals, vision is important for the search for prey, many species even have color vision. In this regard, victims have such adaptive features as a protective reaction, masking and warning coloring, mimicry, etc. In aquatic inhabitants such adaptations are much less developed. The emergence of brightly colored flowers of higher plants is also associated with the characteristics of the pollinator apparatus and, ultimately, with the light regime of the medium.

The terrain and soil properties are also living conditions of terrestrial organisms and, first of all, plants. The properties of the earth's surface, which have an environmental impact on its inhabitants, are combined by “edaphic environmental factors” (from the Greek “edaphos” - “soil”).

In relation to different soil properties, a number of ecological groups of plants can be distinguished. So, according to the reaction to soil acidity, there are:

• 1) acidophilic species - grow on acidic soils with a pH of at least 6.7 (plants of sphagnum bogs);
• 2) neutrophilic - tend to grow on soils with a pH of 6.7-7.0 (most cultivated plants);
• 3) basifilic - grow at a pH of more than 7.0 (muzzle, forest anemone);
• 4) indifferent - can grow on soils with different pH values \u200b\u200b(lily of the valley).

Plants differ in relation to soil moisture. Certain species are confined to different substrates, for example, petrophytes grow on stony soils, Pasmophytes populate loose sands.

The terrain and the nature of the soil affect the specifics of the movement of animals: for example, ungulates, ostriches, bustards, living in open spaces, hard ground, to enhance repulsion during running. In lizards living in loose sand, fingers are fringed with fringes of horny scales that increase support. For terrestrial inhabitants digging holes, dense soil is unfavorable. The nature of the soil in certain cases affects the distribution of terrestrial animals digging holes or burrowing into the ground, or laying eggs in the soil, etc.

Abiotic environmental factors include the substrate and its composition, humidity, temperature, light and other types of radiation in nature, and its composition, and microclimate. It should be noted that temperature, air composition, humidity and light can be conditionally classified as "individual", and the substrate, climate, microclimate, etc. - to "complex" factors.

The substrate (literally) is the place of attachment. For example, for woody and herbaceous forms of plants, for soil microorganisms it is soil. In some cases, the substrate can be considered a synonym for habitat (for example, soil is an edaphic habitat). The substrate is characterized by a specific chemical composition, which affects organisms. If the substrate is understood as a habitat, then in this case it is a complex of biotic and abiotic factors characteristic of it, to which this or that organism adapts.

Characterization of temperature as an abiotic environmental factor

The role of temperature as an environmental factor is that it affects the metabolism: at low temperatures, the rate of bioorganic reactions slows down significantly, and at high temperatures it increases significantly, which leads to an imbalance in the course of biochemical processes, and this causes various diseases, and sometimes and death.

The effect of temperature on plant organisms

Temperature is not only a factor determining the ability of plants to live in a particular territory, but for some plants it affects the process of their development. Thus, winter varieties of wheat and rye, which during germination did not undergo the process of “vernalization” (exposure to low temperatures), do not produce seeds when they grow under the most favorable conditions.

To tolerate exposure to low temperatures, plants have various devices.

1. In winter, the cytoplasm loses water and accumulates substances that have the effect of “antifreeze” (these are monosugar, glycerin and other substances) - concentrated solutions of such substances freeze only at low temperatures.

2. The transition of plants to a stage (phase) that is resistant to low temperatures - the stage of spores, seeds, tubers, bulbs, rhizomes, root crops, etc. Tree and shrub forms of plants drop leaves, the stems are covered with a cork that has high thermal insulation properties, and antifreeze substances accumulate in living cells.

The effect of temperature on animal organisms

Temperature affects poikilothermic and homeothermic animals in different ways.

Poikilothermic animals are active only in the period of temperatures optimal for their vital functions. During low temperatures, they hibernate (amphibians, reptiles, arthropods, etc.). Some insects overwinter either in the form of eggs or in the form of pupae. Being in hibernation is characterized by a state of suspended animation, in which metabolic processes are very inhibited and the body can do without food for a long time. Poikilothermic animals can also hibernate under the influence of high temperatures. Thus, animals in the lower latitudes are in burrows during the hot time of the day, and the period of their active life falls in the early morning or late evening (or they lead a nocturnal lifestyle).

Animal organisms fall into hibernation not only due to the influence of temperature, but also due to other factors. So, a bear (a homoyothermal animal) hibernates in winter due to a lack of food.

Homoyothermic animals are less dependent on temperature in their life, but temperature affects them in terms of the presence (absence) of food supply. These animals have the following adaptations to overcome the effects of low temperatures:

1) animals move from colder areas to warmer ones (bird migrations, mammalian migrations);

2) change the nature of the cover (summer fur or plumage is replaced by a thicker winter; accumulate a large layer of fat - wild pigs, seals, etc.);

3) fall into hibernation (for example, a bear).

Homoothermal animals have devices to reduce the effects of temperatures (both elevated and decreased). So, a person has sweat glands that change the nature of secretion at elevated temperatures (the amount of secretion increases), the lumen of blood vessels in the skin changes (at low temperatures it decreases, and at high temperatures it increases), etc.

Radiation as an abiotic factor

And in the life of plants, and in the life of animals, a huge role is played by various radiations, which either fall on the planet from the outside (sun rays), or stand out from the bowels of the Earth. Here we consider mainly solar radiation.

Solar radiation is heterogeneous and consists of electromagnetic waves of different lengths and, therefore, possess different energies. Rays of the Earth reach the rays of both the visible and invisible spectrum. The rays of the invisible spectrum include infrared and ultraviolet rays, and the rays of the visible spectrum have the seven most distinguishable rays (from red to purple). radiation quanta increases from infrared to ultraviolet (i.e., ultraviolet rays contain quanta of the shortest waves and the highest energy).

The sun's rays have several environmentally important functions:

1) due to the sun's rays on the surface of the Earth, a certain temperature regime is implemented, having a latitudinal and vertical zonal character;

In the absence of human exposure, the composition of the air, however, may vary depending on the altitude (the oxygen and carbon dioxide content decreases with altitude, since these gases are heavier than nitrogen). The air of coastal areas is enriched with water vapor, which contain sea salts in a dissolved state. Forest air differs from field air with impurities of compounds secreted by various plants (for example, pine forest air contains a large amount of resinous substances and ethers that kill pathogens, so this air is healing for tuberculosis patients).

The most important complex abiotic factor is climate.

Climate is a cumulative abiotic factor, which includes a certain composition and level of solar radiation, the level of temperature and humidity exposure associated with it, and a certain regime of winds. The climate also depends on the nature of the vegetation growing in the given territory, and on the terrain.

On Earth, a certain latitudinal and vertical climatic zonality is observed. There are humid tropical, subtropical, sharply continental and other types of climate.

Repeat information about different types of climate according to the textbook of physical geography. Consider the climate features of the territory in which you live.

Climate as an aggregate factor forms one or another type of vegetation (flora) and the type of fauna closely associated with it. Great impact on the climate have human settlements. The climate of large cities differs from the climate of suburban areas.

Compare the temperature regime of the city in which you live and the temperature regime of the area where the city is located.

As a rule, the temperature in the city (especially in the center) is always higher than in the region.

Climate is closely related to the microclimate. The cause of the microclimate are differences in the relief in this territory, the presence of water bodies, which leads to a change in conditions in different territories of this climatic zone. Even in a relatively small territory of a summer cottage, in its separate parts various conditions for plant growth may arise due to different lighting conditions.