Behavioral adaptations of organisms to the action of ecological factors. Examples. Mechanisms of plant adaptation to adverse environmental conditions Types of adaptations with examples

The identification of limiting factors is of great practical importance. First of all, for growing crops: applying the necessary fertilizers, liming the soil, reclamation, etc. allow to increase productivity, improve soil fertility, improve the existence of cultivated plants.

1. What does the prefix "evry" and "steno" mean in the species name? Give examples of eurybionts and stenobionts.

Wide tolerance limit of the species in relation to abiotic environmental factors, denoted by adding prefixes to the name of the factor "evry. The inability to tolerate significant fluctuations in factors or a low endurance limit is characterized by the prefix "steno", for example, stenothermic animals. Small temperature changes have little effect on eurythermal organisms and can be fatal for stenothermic ones. The species adapted to low temperatures is cryophilic(from the Greek krios - cold), and to high temperatures - thermophilic. Similar patterns apply to other factors as well. Plants can be hydrophilic, i.e. demanding on water and xerophilic(dry-hardy).

In relation to content salts in the habitat, eurygales and stenogals are distinguished (from Greek gals - salt), to illumination - euryphotes and stenophots, in relation to to the acidity of the environment- Euryionic and stenionic species.

Since eurybiontism makes it possible to populate a variety of habitats, and stenobiontism sharply narrows the range of places suitable for the species, these 2 groups are often called evry - and stenobionts. Many terrestrial animals living in a continental climate are able to withstand significant fluctuations in temperature, humidity, and solar radiation.

Stenobionts include- orchids, trout, Far Eastern hazel grouse, deep-sea fish).

Animals that are stenobiont simultaneously with respect to several factors are called stenobionts in the broad sense of the word ( fish that live in mountain rivers and streams, do not tolerate too high temperatures and low oxygen content, inhabitants of the humid tropics, unadapted to low temperatures and low air humidity).

The eurybionts are Colorado potato beetle, mouse, rats, wolves, cockroaches, reeds, wheatgrass.

1. Adaptation of living organisms to environmental factors. Types of adaptation.

adaptation ( from lat. adaptation - adaptation ) - this is an evolutionary adaptation of the organisms of the environment, expressed in a change in their external and internal features.

Individuals that for some reason have lost the ability to adapt, in the conditions of changes in the regimes of environmental factors, are doomed to elimination, i.e. to extinction.

Types of adaptation: morphological, physiological and behavioral adaptations.

Morphology is the doctrine of the external forms of organisms and their parts.

1.Morphological adaptation- this is an adaptation that manifests itself in adaptation to fast swimming in aquatic animals, to survival in conditions of high temperatures and moisture deficiency - in cacti and other succulents.

2.Physiological adaptations consist in the features of the enzymatic set in the digestive tract of animals, determined by the composition of the food. For example, the inhabitants of dry deserts are able to provide the need for moisture due to the biochemical oxidation of fats.

3.Behavioral (ethological) adaptations appear in a variety of forms. For example, there are forms of adaptive behavior of animals aimed at ensuring optimal heat exchange with the environment. Adaptive behavior can be manifested in the creation of shelters, movement in the direction of more favorable, preferred temperature conditions, the choice of places with optimal humidity or light. Many invertebrates are characterized by a selective attitude towards light, which manifests itself in approaching or moving away from the source (taxis). Diurnal and seasonal migrations of mammals and birds are known, including migrations and flights, as well as intercontinental movements of fish.

Adaptive behavior can manifest itself in predators in the process of hunting (tracking and chasing prey) and in their prey (hiding, confusing the trail). The behavior of animals during the mating season and during the rearing of offspring is exceptionally specific.

There are two types of adaptation to external factors. Passive way of adaptation- this is an adaptation according to the type of tolerance (tolerance, endurance) consists in the emergence of a certain degree of resistance to this factor, the ability to maintain functions when the force of its influence changes .. This type of adaptation is formed as a characteristic species property and is realized at the cellular and tissue level. The second type of fixture active. In this case, the body, using specific adaptive mechanisms, compensates for the changes caused by the influencing factor, so that the internal environment remains relatively constant. Active adaptations are adaptations of a resistant type (resistance) that maintain the homeostasis of the internal environment of the body. An example of a tolerant type of adaptation is poikiloosmotic animals, an example of a resistant type is homoyosmotic .

1. Define a population. Name the main group characteristics of the population. Give examples of populations. Growing, stable and dying populations.

population- a group of individuals of the same species that interact with each other and jointly inhabit a common territory. The main characteristics of the population are as follows:

1. Number - the total number of individuals in a certain area.

2. Population density - the average number of individuals per unit area or volume.

3. Fertility - the number of new individuals that appeared per unit of time as a result of reproduction.

4. Mortality - the number of dead individuals in the population per unit of time.

5. Population growth - the difference between fertility and mortality.

6. Growth rate - average growth per unit of time.

Populations are characterized by a certain organization, the distribution of individuals over the territory, the ratio of groups by sex, age, and behavioral characteristics. It is formed, on the one hand, on the basis of the general biological properties of the species, and on the other hand, under the influence of abiotic environmental factors and populations of other species.

The structure of the population is unstable. The growth and development of organisms, the birth of new ones, death from various causes, changes in environmental conditions, an increase or decrease in the number of enemies - all this leads to a change in various ratios within the population.

Increasing or growing population- this is a population in which young individuals predominate, such a population is growing in number or is being introduced into the ecosystem (for example, countries of the "third" world); More often, there is an excess of births over deaths and the population grows to such an extent that an outbreak of mass reproduction may occur. This is especially true for small animals.

With a balanced intensity of fertility and mortality, a stable population. In such a population, mortality is compensated by growth and its number, as well as its range, are kept at the same level. . Stable population - this is a population in which the number of individuals of different ages varies evenly and has the character of a normal distribution (as an example, we can name the population of Western Europe).

Decreasing (dying) population is a population in which the death rate exceeds the birth rate . A declining or dying population is a population dominated by older individuals. An example is Russia in the 1990s.

However, it cannot shrink indefinitely either.. At a certain level of abundance, the intensity of mortality begins to fall, and fecundity increases. . Ultimately, a declining population, having reached a certain minimum number, turns into its opposite - a growing population. The birth rate in such a population gradually increases and at a certain moment levels off with mortality, i.e., the population becomes stable for a short period of time. Decreasing populations are dominated by old individuals that are no longer able to reproduce intensively. This age structure indicates unfavorable conditions.

1. Ecological niche of the organism, concepts and definitions. Habitat. Mutual arrangement of ecological niches. The ecological niche of man.

Any kind of animal, plant, microbe is able to normally live, feed, reproduce only in the place where it has been "registered" by evolution over many millennia, starting from its ancestors. To refer to this phenomenon, biologists have borrowed term from architecture - the word "niche" and they began to say that each type of living organism occupies its own, unique ecological niche in nature.

Ecological niche of an organism- this is the totality of all its requirements for environmental conditions (composition and regimes of environmental factors) and the place where these requirements are met, or the totality of the set of biological characteristics and physical parameters of the environment that determine the conditions for the existence of a particular species, its transformation of energy, the exchange of information with environment and others like them.

The concept of an ecological niche is usually used when using the relationships of ecologically close species belonging to the same trophic level. The term "ecological niche" was proposed by J. Grinnell in 1917 to characterize the spatial distribution of species, that is, the ecological niche was defined as a concept close to the habitat. C. Elton defined an ecological niche as the position of a species in a community, emphasizing the particular importance of trophic relationships. A niche can be thought of as part of an imaginary multi-dimensional space (hypervolume), the individual dimensions of which correspond to the factors necessary for the species. The more the parameter varies, i.e. the adaptability of a species to a certain environmental factor, the wider its niche. The niche can also increase in the case of weakened competition.

habitat of the species- this is the physical space occupied by a species, organism, community, it is determined by the totality of the conditions of the abiotic and biotic environment, providing the entire development cycle of individuals of the same species.

The habitat of the species can be designated as "spatial niche".

The functional position in the community, in the ways of processing matter and energy in the process of nutrition, is called trophic niche.

Figuratively speaking, if a habitat is, as it were, the address of organisms of a given species, then a trophic niche is a profession, the role of an organism in its habitat.

The combination of these and other parameters is commonly called an ecological niche.

ecological niche(from the French niche - a recess in the wall) - this is the place occupied by a biological species in the biosphere, includes not only its position in space, but also its place in trophic and other interactions in the community, as it were, the “profession” of the species.

Niche ecological fundamental(potential) is an ecological niche in which a species can exist in the absence of competition from other species.

Ecological niche realized (real) – ecological niche, part of a fundamental (potential) niche that a species can defend in competition with other species.

According to the relative position of the niches of the two types, they are divided into three types: non-contiguous ecological niches; contiguous but not overlapping niches; contiguous and overlapping niches.

Man is one of the representatives of the animal kingdom, a biological species of the class of mammals. Despite the fact that it has many specific properties (mind, articulate speech, labor activity, biosociality, etc.), it has not lost its biological essence and all the laws of ecology are valid for it to the same extent as for other living organisms. . Man has his own, only his own, ecological niche. The space in which the human niche is localized is very limited. As a biological species, a person can live only within the land of the equatorial belt (tropics, subtropics), where the hominid family arose.

1. Formulate the fundamental law of Gause. What is a "life form"? What ecological (or life) forms are distinguished among the inhabitants of the aquatic environment?

Both in the plant and in the animal world, interspecific and intraspecific competition is very widespread. There is a fundamental difference between them.

Rule (or even law) Gause: two species cannot occupy the same ecological niche at the same time and therefore necessarily crowd out each other.

In one of the experiments, Gause bred two types of ciliates - Paramecium caudatum and Paramecium aurelia. As food, they regularly received one of the types of bacteria that does not multiply in the presence of paramecium. If each type of ciliate was cultivated separately, then their populations grew according to a typical sigmoid curve (a). At the same time, the number of paramecia was determined by the amount of food. But when coexisting, paramecia began to compete, and P. aurelia completely replaced its competitor (b).

Rice. Competition between two closely related species of ciliates occupying a common ecological niche. a - Paramecium caudatum; b - P. aurelia. 1. - in one culture; 2. - in a mixed culture

With the joint cultivation of ciliates, after a while only one species remained. At the same time, ciliates did not attack individuals of another type and did not emit harmful substances. The explanation lies in the fact that the studied species differed in unequal growth rates. In the competition for food, the fastest breeding species won.

When breeding P. caudatum and P. bursaria there was no such displacement, both species were in equilibrium, the latter being concentrated on the bottom and walls of the vessel, and the former in free space, i.e., in another ecological niche. Experiments with other types of ciliates have demonstrated the regularity of the relationship between prey and predator.

Gauze principle is called the principle elimination competitions. This principle leads either to the ecological separation of closely related species, or to a decrease in their density where they are able to coexist. As a result of competition, one of the species is ousted. The Gause principle plays a huge role in the development of the concept of a niche, and also forces ecologists to look for answers to a number of questions: How do similar species coexist? How big must be the differences between species in order for them to coexist? How do you avoid competitive exclusion?

The life form of the species it is a historically developed complex of its biological, physiological and morphological properties, which determines a certain reaction to the influence of the environment.

Among the inhabitants of the aquatic environment (hydrobionts), the classification distinguishes the following life forms.

1.Neuston(from the Greek neuston - able to swim) – collection of marine and freshwater organisms that live near the surface of the water , for example, mosquito larvae, many protozoa, water strider bugs, and from plants, the well-known duckweed.

2. Closer to the surface of the water inhabits plankton.

Plankton(from Greek planktos - soaring) - floating organisms capable of making vertical and horizontal movements mainly in accordance with the movement of water masses. Allocate phytoplankton photosynthetic free-swimming algae and zooplankton- small crustaceans, larvae of mollusks and fish, jellyfish, small fish.

3.Nekton(from the Greek nektos - floating) - free-floating organisms capable of independent vertical and horizontal movement. Nekton lives in the water column - these are fish, in the seas and oceans, amphibians, large aquatic insects, crustaceans, also reptiles (sea snakes and turtles) and mammals: cetaceans (dolphins and whales) and pinnipeds (seals).

4. Periphyton(from Greek peri - around, about, phyton - plant) - animals and plants attached to the stems of higher plants and rising above the bottom (mollusks, rotifers, bryozoans, hydras, etc.).

5. Benthos ( from the Greek benthos - depth, bottom) - benthic organisms leading an attached or free lifestyle, including: living in the thickness of the bottom sediment. These are mainly molluscs, some lower plants, crawling insect larvae, and worms. The bottom layer is inhabited by organisms that feed mainly on decaying remains.

1. What is biocenosis, biogeocenosis, agrocenosis? The structure of biogeocenosis. Who is the founder of the doctrine of biocenosis? Examples of biogeocenoses.

Biocenosis(from Greek koinos - common bios - life) is a community of interacting living organisms, consisting of plants (phytocenosis), animals (zoocenosis), microorganisms (microbocenosis) adapted to coexist in a given territory.

The concept of "biocenosis" - conditional, since organisms cannot live outside the environment of existence, but it is convenient to use it in the process of studying ecological relationships between organisms. Depending on the area, the attitude to human activity, the degree of saturation, usefulness, etc. there are biocenoses of land, water, natural and anthropogenic, saturated and unsaturated, full-membered and non-full-membered.

Biocenoses, like populations - this is a supra-organismal level of life organization, but of a higher rank.

The sizes of biocenotic groups are different- these are also large communities of lichen pillows on tree trunks or a rotting stump, but this is also a population of steppes, forests, deserts, etc.

The community of organisms is called biocenosis, and the science that studies the community of organisms - biocenology.

V.N. Sukachev the term has been proposed (and generally accepted) to refer to communities biogeocenosis(from Greek bios - life, geo - Earth, cenosis - community) - it is a set of organisms and natural phenomena characteristic of a given geographical area.

The structure of biogeocenosis includes two components biotic - community of living plant and animal organisms (biocenosis) - and abiotic - a set of non-living environmental factors (ecotope, or biotope).

Space with more or less homogeneous conditions, which occupies a biocenosis, is called a biotope (topis - place) or ecotope.

Ecotop includes two main components: climatetop- the climate in all its diverse manifestations and edaphotop(from the Greek edafos - soil) - soil, relief, water.

Biogeocenosis\u003d biocenosis (phytocenosis + zoocenosis + microbocenosis) + biotope (climatotop + edaphotop).

Biogeocenoses - these are natural formations (they contain the element "geo" - the Earth ) .

Examples biogeocenoses there may be a pond, a meadow, a mixed or single-species forest. At the level of biogeocenosis, all processes of transformation of energy and matter in the biosphere take place.

Agrocenosis(from Latin agraris and Greek koikos - common) - a community of organisms created by man and artificially supported by him with increased productivity (productivity) of one or more selected plant or animal species.

Agrocenosis differs from biogeocenosis main components. It cannot exist without human support, as it is an artificially created biotic community.

1. The concept of "ecosystem". Three principles of functioning of ecosystems.

ecological system- one of the most important concepts of ecology, abbreviated as an ecosystem.

Ecosystem(from the Greek oikos - dwelling and system) - this is any community of living beings, together with their habitat, connected inside by a complex system of relationships.

Ecosystem - these are supraorganismal associations, including organisms and inanimate (inert) environment, which are in interaction, without which it is impossible to maintain life on our planet. This is a community of plant and animal organisms and an inorganic environment.

Based on the interaction of living organisms that form an ecosystem, with each other and with their habitat, in any ecosystem, interdependent aggregates are distinguished biotic(living organisms) and abiotic(inert or inanimate nature) components, as well as environmental factors (such as solar radiation, humidity and temperature, atmospheric pressure), anthropogenic factors other.

To abiotic components of ecosystems include inorganic substances - carbon, nitrogen, water, atmospheric carbon dioxide, minerals, organic substances found mainly in the soil: proteins, carbohydrates, fats, humic substances, etc., which have entered the soil after the death of organisms.

To the biotic components of the ecosystem include producers, autotrophs (plants, chemosynthetics), consumers (animals) and detritophages, decomposers (animals, bacteria, fungi).

Kazan physiological school. F.V. Ovsyannikov, N.O. Kovalevsky, N.A. Mislavsky, A.V. Kibyakov

Animals and plants are forced to adapt to many factors, and these adaptations are developed over a certain period of time, often in the process of evolution and natural selection, being fixed at the genetic level.

Adaptation(from lat. adapto - I adapt) - adaptations of the structure and functions of organisms to environmental conditions in the process of evolution.

When analyzing the organization of any animal and plant, a striking correspondence of the form and functions of the organism to environmental conditions is always found. So, among marine mammals dolphins they have the most advanced adaptations for rapid movement in the aquatic environment: a torpedo-shaped shape, a special structure of the skin and subcutaneous tissue, which increases the streamlining of the body, and, consequently, the speed of sliding in water.

There are three main forms of manifestation of adaptations: anatomical-morphological, physiological and behavioral.

Anatomical and morphological adaptations are some external and internal features in the structure of certain organs of plants and animals that allow them to live in a certain environment with a certain combination of environmental factors. In animals, they are often associated with lifestyle, the nature of nutrition. Examples:

Hard tortoise shell for protection from predatory animals

Woodpecker - chisel-shaped beak, hard tail, characteristic arrangement of fingers.

Physiological adaptations consist in the ability of organisms to change some of their physiological processes during critical periods in their life

· The smell of the flower can serve to attract insects and thereby promote pollination of the plant.

· Deep dormancy in many plants growing in the middle latitudes of the northern hemisphere, falling into a stupor or hibernation in some animals with the onset of a cold period).

· Biological antifreezes that increase the viscosity of internal media and prevent the formation of ice crystals that would destroy cells (up to 10% in ants, up to 30% in wasps).

In the dark, the sensitivity of the eye to light increases many thousands of times within an hour, which is associated both with the restoration of sight, pigments, and with changes in the nerve elements and nerve cells of the cerebral cortex.

· An example of physiological adaptations are also the features of the enzymatic set in the digestive tract of animals, determined by the set and composition of food. Thus, desert dwellers are able to provide their need for moisture by biochemical oxidation of fats.

Behavioral(ethological) adaptations are forms of adaptive behavior of animals. Examples:

· To ensure normal heat exchange with the environment: the creation of shelters, daily and seasonal migration of animals in order to select the optimal temperature conditions.

Hummingbird Oreotrochis estella, living in the high Andes, builds nests on the rocks, and on the side facing the East. During the night, the stones give off the heat accumulated during the day, thereby providing a comfortable temperature until the morning.

· In areas with a harsh climate, but snowy winters, the temperature under the snow can be 15-18ºС higher than outside. It is estimated that the white partridge, spending the night in a snowy hole, saves up to 45% of energy.

Many animals use group roosting: pikas of the genus Certhia(birds) gather in cold weather in groups of up to 20 individuals. A similar phenomenon has been described in rodents.

· Adaptive behavior can appear in predators in the process of tracking and chasing prey.

Most adaptations is a combination of the above types. For example, bloodsucking in mosquitoes is provided by a complex combination of such adaptations as the development of specialized parts of the oral apparatus adapted for sucking, the formation of search behavior to find a prey animal, and the production of special secretions by the salivary glands that prevent the blood being sucked from clotting.

One of the fundamental properties of living nature is the cyclicity of most of the processes occurring in it, which ensures the adaptation of plants and animals during their development with the main periodic factors. Let us dwell on such a phenomenon in wildlife as photoperiodism.

Photoperiodism - response of organisms to seasonal changes in day length. Opened by V. Garner and N. Allard in 1920 during selection work with tobacco.

Light has a leading influence on the manifestation of daily and seasonal activity of organisms. This is an important factor, since it is the change in illumination that causes the alternation of a period of rest and intensive life, many biological phenomena in plants and animals (i.e., affects the biorhythm of organisms).

For example, 43% of the sun's rays reach the Earth's surface. Plants are able to capture from 0.1 to 1.3%. They absorb the yellow-green spectrum.

And a signal of the approach of winter for plants and animals is a decrease in the length of the day. Plants undergo a gradual physiological restructuring, the accumulation of a supply of energy substances before winter dormancy. By photoperiodic reaction plant organisms are divided into two groups:

Short-day organisms - flowering and fruiting occurs at 8-12 hours of light (buckwheat, millet, hemp, sunflower).

long day organisms. For flowering and fruiting in long-day plants, it is necessary to lengthen the day to 16-20 hours (plants of temperate latitudes), for which a decrease in day length to 10-12 hours is a signal of the approach of an unfavorable autumn-winter period. These are potatoes, wheat, spinach.

· Neutral to length for the plant. Flowering occurs at any length of the day. These are dandelion, mustard and tomato.

The same is found in animals. During the day, the activity of each organism falls on certain hours. The mechanisms that allow organisms to change their state cyclically are called "biological clocks".

Bibliographic list for the section

1. Galperin, M.V. General ecology: [proc. for avg. prof. education] / M.V. Galperin. - M. : Forum: Infra-M, 2006. - 336 p.

2. Korobkin, V.I. Ecology [Text] / V.I. Korobkin, L.V. Peredelsky. - Rostov-on-Don: Phoenix, 2005. - 575 p.

3. Mirkin, B.M. Fundamentals of general ecology [Text]: textbook. allowance for university students studying natural sciences. specialties / B.M. Mirkin, L.G. Naumov; [ed. G.S. Rosenberg]. - M. : Univ. book, 2005. - 239 p.

4. Stepanovskikh, A.S. General ecology: [proc. for universities on ecol. specialties] / A.S. Stepanovsky. - 2nd ed., add. and reworked. - M. : UNITI, 2005. - 687 p.

5. Furyaev, V.V. General ecology and biology: textbook. allowance for students of the specialty 320800 pts. forms of education / V.V. Furyaev, A.V. Furyaeva; Feder. education agency, Sib. state technol. un-t, Institute of Forests named after. V. N. Sukacheva. - Krasnoyarsk: SibGTU, 2006. - 100 p.

6. Golubev, A.V. General ecology and environmental protection: [proc. manual for all specialties] / A.V. Golubev, N.G. Nikolaevskaya, T.V. Sharapa; [ed. ed.] ; State. educate. institution of higher prof. Education "Moscow. state. un-t forest". - M. : MGUL, 2005. - 162 p.

7. Korobkin, V.I. Ecology in questions and answers [Text]: textbook. allowance for university students / V.I. Korobkin, L.V. Peredelsky. - 2nd ed., revised. and additional - Rostov n / a: Phoenix, 2005. - 379 p. : schemes. - Bibliography: p. 366-368. - 103.72 rubles

Security questions for section 3

1. The concept of habitat, its types.

2. What are environmental factors, how are they classified?

3. The concept of a limiting factor, examples.

4. The law of optimum-pessimum (figure). Examples.

5. Law of interaction of environmental factors. Examples.

6. The law of tolerance (Shelford). Examples.

7. Environmental rules: D. Allen, K. Bergman, K. Gloger.

8. Adaptations of living organisms, their ways and forms. Examples.

9. Photoperiodism, biological rhythms: concept, examples.

SECTION 4: POPULATION ECOLOGY

Such an observation is interesting. In animals of the northern populations, all elongated parts of the body - limbs, tail, ears - are covered with a dense layer of wool and look relatively shorter than in representatives of the same species, but living in a hot climate.

This pattern, known as the Alain rule, applies to both wild and domestic animals.

There is a noticeable difference in the body structure of the northern fox and the fennec fox in the south, the northern wild boar and the wild boar in the Caucasus. Outbred domestic dogs in the Krasnodar Territory, cattle of local selection are distinguished by a lower live weight compared to representatives of these species, say, Arkhangelsk.

Often animals from the southern populations of long-legged and long-eared. Large ears, unacceptable at low temperatures, arose as an adaptation to life in a hot zone.

And the animals of the tropics have just huge ears (elephants, rabbits, ungulates). The ears of the African elephant are indicative, the area of ​​\u200b\u200bwhich is 1/6 of the surface of the entire body of the animal. They have abundant innervation and vascularity. In hot weather, about 1/3 of the entire circulating blood passes through the circulatory system of the ear shells in an elephant. As a result of increased blood flow, excessive heat is given off to the external environment.

The desert hare Lapus alleni is even more impressive with its adaptive abilities to high temperatures. In this rodent, 25% of the entire body surface falls on bare auricles. It is not clear what the main biological task of such ears is: to detect the approach of danger in time or to participate in thermoregulation. Both the first and the second task are solved by the animal very effectively. The rodent has a keen ear. The developed circulatory system of the auricles with a unique vasomotor ability serves only thermoregulation. By increasing and limiting blood flow through the auricles, the animal changes heat transfer by 200-300%. Its hearing organs perform the function of maintaining thermal homeostasis and saving water.

Due to the saturation of the auricles with thermosensitive nerve endings and rapid vasomotor reactions, a large amount of excess thermal energy is transferred from the surface of the auricles to the external environment in both the elephant and especially the lepus.

The structure of the body of a relative of modern elephants, the mammoth, fits well into the context of the problem under discussion. This northern analogue of the elephant, judging by the preserved remains found in the tundra, was much larger than its southern relative. But the ears of the mammoth had a smaller relative area and, moreover, were covered with thick hair. The mammoth had relatively short limbs and a short trunk.

Long limbs are unfavorable at low temperatures, since too much thermal energy is lost from their surface. But in hot climates, long limbs are a useful adaptation. In desert conditions, camels, goats, horses of local selection, as well as sheep, cats, as a rule, have long legs.

According to H. Hensen, as a result of adaptation to low temperatures in animals, the properties of subcutaneous fat and bone marrow change. In arctic animals, bone fat from the phalanx of the fingers has a low melting point and does not freeze even in severe frosts. However, bone fat from bones that do not come into contact with a cold surface, such as the femur, has conventional physicochemical properties. Liquid fat in the bones of the lower extremities provides thermal insulation and joint mobility.

The accumulation of fat is noted not only in northern animals, for which it serves as a thermal insulation and a source of energy during a period when food is not available due to severe bad weather. Fat accumulate and animals living in hot climates. But the quality, quantity and distribution of body fat in northern and southern animals is different. In wild arctic animals, fat is distributed evenly throughout the body in the subcutaneous tissue. In this case, the animal forms a kind of heat-insulating capsule.

In animals of the temperate zone, fat as a heat insulator accumulates only in species with a poorly developed coat. In most cases, stored fat serves as a source of energy during the hungry winter (or summer) period.

In hot climates, subcutaneous fat deposits carry a different physiological burden. The distribution of body fat throughout the body of animals is characterized by great unevenness. Fat is localized in the upper and back parts of the body. For example, in African hoofed savannahs, the subcutaneous fat layer is localized along the spine. It protects the animal from the scorching sun. The belly is completely free of fat. It also makes a lot of sense. Ground, grass or water, which is colder than air, ensures efficient heat removal through the abdominal wall in the absence of fat. Small fat deposits and in animals in a hot climate are a source of energy for a period of drought and the associated hungry existence of herbivores.

The internal fat of animals in a hot and arid climate performs another extremely useful function. In conditions of lack or complete absence of water, internal fat serves as a source of water. Special studies show that the oxidation of 1000 g of fat is accompanied by the formation of 1100 g of water.

An example of unpretentiousness in the arid conditions of the desert are camels, fat-tailed and fat-tailed sheep, and zebu-like cattle. The mass of fat accumulated in the humps of a camel and the fat tail of a sheep is 20% of their live weight. Calculations show that a 50-kilogram fat-tailed sheep has a water supply of about 10 liters, and a camel even more - about 100 liters. The last examples illustrate the morphophysiological and biochemical adaptations of animals to extreme temperatures. Morphological adaptations extend to many organs. In northern animals, there is a large volume of the gastrointestinal tract and a large relative length of the intestine, they deposit more internal fat in the omentums and the perirenal capsule.

Animals of the arid zone have a number of morphological and functional features of the system of urination and excretion. As early as the beginning of the 20th century. morphologists have found differences in the structure of the kidneys of desert and temperate animals. In hot climate animals, the medulla is more developed due to an increase in the rectal tubular part of the nephron.

For example, in an African lion, the thickness of the renal medulla is 34 mm, while in a domestic pig it is only 6.5 mm. The ability of the kidneys to concentrate urine is positively correlated with the length of the loop of Hendle.

In addition to structural features in animals of the arid zone, functional features of the urinary system were found. So, for a kangaroo rat, the pronounced ability of the bladder to reabsorb water from the secondary urine is normal. In the ascending and descending channels of the loop of Hendle, urea is filtered - a process common to the nodule part of the nephron.

The adaptive functioning of the urinary system is based on neurohumoral regulation with a pronounced hormonal component. In kangaroo rats, the concentration of the hormone vasopressin is increased. So, in the urine of a kangaroo rat, the concentration of this hormone is 50 U / ml, in a laboratory rat - only 5-7 U / ml. In the pituitary tissue of a kangaroo rat, the content of vasopressin is 0.9 U/mg, in a laboratory rat it is three times less (0.3 U/mg). Under water deprivation, differences between animals persist, although the secretory activity of the neurohypophysis increases in both one and the other animal.

The loss of live weight during water deprivation in arid animals is lower. If a camel loses 2-3% of its live weight during a working day, receiving only low-quality hay, then a horse and a donkey under the same conditions will lose 6-8% of their live weight due to dehydration.

The temperature of the habitat has a significant impact on the structure of the skin of animals. In cold climates, the skin is thicker, the coat is thicker, and there are downs. All this helps to reduce the thermal conductivity of the body surface. In animals of a hot climate, the opposite is true: thin skin, sparse hair, low heat-insulating properties of the skin as a whole.

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The grandiose inventions of the human mind never cease to amaze, there is no limit to fantasy. But what nature has been creating for many centuries surpasses the most creative ideas and designs. Nature has created more than one and a half million species of living individuals, each of which is individual and unique in its forms, physiology, adaptability to life. Examples of organisms adapting to constantly changing living conditions on the planet are examples of the wisdom of the creator and a constant source of problems for biologists to solve.

Adaptation means adaptability or habituation. This is a process of gradual rebirth of the physiological, morphological or psychological functions of a creature in a changed environment. Both individual individuals and entire populations undergo changes.

A vivid example of direct and indirect adaptation is the survival of flora and fauna in the zone of increased radiation around the Chernobyl nuclear power plant. Direct adaptability is characteristic of those individuals who managed to survive, get used to and begin to multiply, some did not stand the test and died (indirect adaptation).

Since the conditions of existence on Earth are constantly changing, the processes of evolution and fitness in living nature are also a continuous process.

A recent example of adaptation is changing the habitat of a colony of green Mexican arating parrots. Recently, they have changed their habitual habitat and settled in the very mouth of the Masaya volcano, in an environment constantly saturated with high concentration sulfuric gas. Scientists have not yet given an explanation for this phenomenon.

Types of adaptation

A change in the whole form of an organism's existence is a functional adaptation. An example of adaptation, when changing conditions lead to mutual adaptation of living organisms to each other, is a correlative adaptation or co-adaptation.

Adaptation can be passive, when the functions or structure of the subject occur without his participation, or active, when he consciously changes his habits to match the environment (examples of people adapting to natural conditions or society). There are cases when the subject adapts the environment to his needs - this is an objective adaptation.

Biologists divide the types of adaptation according to three criteria:

• Morphological.
• Physiological.
• behavioral or psychological.

Examples of adaptation of animals or plants in their pure form are rare, most cases of adaptation to new conditions occur in mixed forms.

Morphological adaptations: examples

Morphological changes are changes in the shape of the body, individual organs or the entire structure of a living organism that have occurred in the process of evolution.

The following are morphological adaptations, examples from the animal and plant world, which we take for granted:

• The transformation of leaves into spines in cacti and other plants of arid regions.
• Turtle shell.
• Streamlined body shapes of inhabitants of reservoirs.

Physiological adaptations: examples

Physiological adaptation is a change in a number of chemical processes occurring inside the body.

• The release of a strong scent by flowers to attract insects contributes to dusting.
• The state of anabiosis, which the simplest organisms are able to enter, allows them to maintain their vital activity after many years. The oldest bacterium capable of reproduction is 250 years old.
• The accumulation of subcutaneous fat, which is converted into water, in camels.

Behavioral (psychological) adaptations

Examples of human adaptation are more associated with the psychological factor. Behavioral characteristics are characteristic of flora and fauna. So, in the process of evolution, a change in the temperature regime causes some animals to hibernate, birds fly south to return in the spring, trees shed their leaves and slow down the movement of juices. The instinct to choose the most suitable partner for procreation drives the behavior of animals during the mating season. Some northern frogs and turtles freeze completely for the winter and thaw, reviving with the onset of heat.

Factors causing the need for change

Any adaptation processes are a response to environmental factors that lead to a change in the environment. Such factors are divided into biotic, abiotic and anthropogenic.

Biotic factors are the influence of living organisms on each other, when, for example, one species disappears, which serves as food for another.

Abiotic factors are changes in the surrounding inanimate nature when the climate, soil composition, water availability, and solar activity cycles change. Physiological adaptations, examples of the influence of abiotic factors - equatorial fish that can breathe both in water and on land. They are well adapted to the conditions when the drying up of rivers is a frequent occurrence.

Anthropogenic factors - the influence of human activity that changes the environment.

Habitat adaptations

• illumination. In plants, these are separate groups that differ in the need for sunlight. Light-loving heliophytes live well in open spaces. In contrast, they are sciophytes: plants of forest thickets feel good in shaded places. Among the animals there are also individuals whose design is for an active lifestyle at night or underground.
• Air temperature. On average, for all living things, including humans, the optimal temperature environment is the range from 0 to 50 ° C. However, life exists in almost all climatic regions of the Earth.

Opposite examples of adaptation to abnormal temperatures are described below.

Arctic fish do not freeze due to the production of a unique anti-freeze protein in the blood, which prevents the blood from freezing.

The simplest microorganisms are found in hydrothermal springs, the water temperature in which exceeds the boiling point.

Hydrophyte plants, that is, those that live in or near water, die even with a slight loss of moisture. Xerophytes, on the contrary, are adapted to live in arid regions, and die in high humidity. Among animals, nature has also worked on adapting to aquatic and non-aquatic environments.

Human adaptation

Man's ability to adapt is truly enormous. The secrets of human thinking are far from being fully revealed, and the secrets of the adaptive ability of people will remain a mysterious topic for scientists for a long time to come. The superiority of Homo sapiens over other living beings lies in the ability to consciously change their behavior to meet the requirements of the environment or, conversely, the world around them to suit their needs.

The flexibility of human behavior is manifested daily. If you give the task: "give examples of people's adaptation", the majority begins to recall exceptional cases of survival in these rare cases, and in new circumstances it is typical of a person every day. We try on a new environment at the moment of birth, in kindergarten, school, in a team, when moving to another country. It is this state of accepting new sensations by the body that is called stress. Stress is a psychological factor, but nevertheless, many physiological functions change under its influence. In the case when a person accepts a new environment as positive for himself, the new state becomes habitual, otherwise stress threatens to become protracted and lead to a number of serious diseases.

Human adaptation mechanisms

There are three types of human adaptation:

• Physiological. The simplest examples are acclimatization and adaptability to changing time zones or the daily regime of work. In the process of evolution, various types of people were formed, depending on the territorial place of residence. Arctic, alpine, continental, desert, equatorial types differ significantly in physiological parameters.
• Psychological adaptation. This is the ability of a person to find moments of understanding with people of different psychotypes, in a country with a different level of mentality. A reasonable person tends to change his established stereotypes under the influence of new information, special cases, stress.
• Social adaptation. A type of addiction that is unique to humans.

All adaptive types are closely related to each other, as a rule, any change in habitual existence causes a person to need social and psychological adaptation. Under their influence, the mechanisms of physiological changes come into action, which also adapt to new conditions.

Such a mobilization of all body reactions is called an adaptation syndrome. New body reactions appear in response to sudden changes in the environment. At the first stage - anxiety - there is a change in physiological functions, changes in the work of metabolism and systems. Further, protective functions and organs (including the brain) are connected, they begin to turn on their protective functions and hidden capabilities. The third stage of adaptation depends on individual characteristics: a person either joins a new life and enters the usual course (in medicine, recovery occurs during this period), or the body does not accept stress, and the consequences are already taking a negative form.

Phenomena of the human body

In man, nature has a huge margin of safety, which is used in everyday life only to a small extent. It manifests itself in extreme situations and is perceived as a miracle. In fact, the miracle is inherent in ourselves. An example of adaptation: the ability of people to adapt to a normal life after the removal of a significant part of the internal organs.

Natural innate immunity throughout life can be strengthened by a number of factors or, conversely, weakened by an incorrect lifestyle. Unfortunately, addiction to bad habits is also the difference between a person and other living organisms.

Reactions to unfavorable environmental factors are destructive for living organisms only under certain conditions, and in most cases they have an adaptive value. Therefore, these responses were called by Selye "general adaptation syndrome". In later works, he used the terms "stress" and "general adaptation syndrome" as synonyms.

Adaptation- this is a genetically determined process of formation of protective systems that provide an increase in stability and the flow of ontogenesis in unfavorable conditions for it.

Adaptation is one of the most important mechanisms that increases the stability of a biological system, including a plant organism, in the changed conditions of existence. The better the organism is adapted to some factor, the more resistant it is to its fluctuations.

The genotypically determined ability of an organism to change metabolism within certain limits, depending on the action of the external environment, is called reaction rate. It is controlled by the genotype and is characteristic of all living organisms. Most of the modifications that occur within the limits of the reaction norm are of adaptive significance. They correspond to changes in habitat and provide better survival of plants under fluctuating environmental conditions. In this regard, such modifications are of evolutionary importance. The term "reaction rate" was introduced by V.L. Johansen (1909).

The greater the ability of a species or variety to modify in accordance with the environment, the wider its rate of reaction and the higher the ability to adapt. This property distinguishes resistant varieties of agricultural crops. As a rule, slight and short-term changes in environmental factors do not lead to significant violations of the physiological functions of plants. This is due to their ability to maintain the relative dynamic balance of the internal environment and the stability of the basic physiological functions in a changing external environment. At the same time, sharp and prolonged impacts lead to disruption of many functions of the plant, and often to its death.

Adaptation includes all processes and adaptations (anatomical, morphological, physiological, behavioral, etc.) that increase stability and contribute to the survival of the species.

1.Anatomical and morphological adaptations. In some representatives of xerophytes, the length of the root system reaches several tens of meters, which allows the plant to use groundwater and not experience a lack of moisture in conditions of soil and atmospheric drought. In other xerophytes, the presence of a thick cuticle, pubescence of leaves, and the transformation of leaves into spines reduce water loss, which is very important in conditions of lack of moisture.

Burning hairs and spines protect plants from being eaten by animals.

Trees in the tundra or at high mountain heights look like squat creeping shrubs, in winter they are covered with snow, which protects them from severe frosts.

In mountainous regions with large diurnal temperature fluctuations, plants often have the form of flattened pillows with densely spaced numerous stems. This allows you to keep moisture inside the pillows and a relatively uniform temperature throughout the day.

In marsh and aquatic plants, a special air-bearing parenchyma (aerenchyma) is formed, which is an air reservoir and facilitates the breathing of plant parts immersed in water.

2. Physiological and biochemical adaptations. In succulents, an adaptation for growing in desert and semi-desert conditions is the assimilation of CO 2 during photosynthesis along the CAM pathway. These plants have stomata closed during the day. Thus, the plant keeps the internal water reserves from evaporation. In deserts, water is the main factor limiting plant growth. The stomata open at night, and at this time, CO 2 enters the photosynthetic tissues. The subsequent involvement of CO2 in the photosynthetic cycle occurs in the daytime already with closed stomata.

Physiological and biochemical adaptations include the ability of stomata to open and close, depending on external conditions. The synthesis in cells of abscisic acid, proline, protective proteins, phytoalexins, phytoncides, an increase in the activity of enzymes that counteract the oxidative breakdown of organic substances, the accumulation of sugars in cells and a number of other changes in metabolism contribute to an increase in plant resistance to adverse environmental conditions.

The same biochemical reaction can be carried out by several molecular forms of the same enzyme (isoenzymes), while each isoform exhibits catalytic activity in a relatively narrow range of some environmental parameter, such as temperature. The presence of a number of isoenzymes allows the plant to carry out the reaction in a much wider range of temperatures, compared with each individual isoenzyme. This enables the plant to successfully perform vital functions in changing temperature conditions.

3. Behavioral adaptations, or avoidance of an adverse factor. An example is ephemera and ephemeroids (poppy, starflower, crocuses, tulips, snowdrops). They go through the entire cycle of their development in the spring for 1.5-2 months, even before the onset of heat and drought. Thus, they kind of leave, or avoid falling under the influence of the stressor. In a similar way, early-ripening varieties of agricultural crops form a crop before the onset of adverse seasonal events: August fogs, rains, frosts. Therefore, the selection of many agricultural crops is aimed at creating early ripe varieties. Perennial plants overwinter as rhizomes and bulbs in the soil under snow, which protects them from freezing.

Adaptation of plants to unfavorable factors is carried out simultaneously at many levels of regulation - from a single cell to a phytocenosis. The higher the level of organization (cell, organism, population), the greater the number of mechanisms simultaneously involved in the adaptation of plants to stress.

Regulation of metabolic and adaptive processes inside the cell is carried out with the help of systems: metabolic (enzymatic); genetic; membrane. These systems are closely related. Thus, the properties of membranes depend on gene activity, and the differential activity of the genes themselves is under the control of membranes. The synthesis of enzymes and their activity are controlled at the genetic level, at the same time, enzymes regulate the nucleic acid metabolism in the cell.

On the organism level to the cellular mechanisms of adaptation, new ones are added, reflecting the interaction of organs. Under unfavorable conditions, plants create and retain such a number of fruit elements that are provided in sufficient quantities with the necessary substances to form full-fledged seeds. For example, in the inflorescences of cultivated cereals and in the crowns of fruit trees, under adverse conditions, more than half of the laid ovaries can fall off. Such changes are based on competitive relations between organs for physiologically active and nutrients.

Under stress conditions, the processes of aging and falling of the lower leaves are sharply accelerated. At the same time, the substances necessary for plants move from them to young organs, responding to the survival strategy of the organism. Thanks to the recycling of nutrients from the lower leaves, the younger ones, the upper leaves, remain viable.

There are mechanisms of regeneration of lost organs. For example, the surface of the wound is covered with a secondary integumentary tissue (wound periderm), the wound on the trunk or branch is healed with influxes (calluses). With the loss of the apical shoot, dormant buds awaken in plants and lateral shoots develop intensively. Spring restoration of leaves instead of fallen ones in autumn is also an example of natural organ regeneration. Regeneration as a biological device that provides vegetative propagation of plants by root segments, rhizomes, thallus, stem and leaf cuttings, isolated cells, individual protoplasts, is of great practical importance for crop production, fruit growing, forestry, ornamental gardening, etc.

The hormonal system is also involved in the processes of protection and adaptation at the plant level. For example, under the influence of unfavorable conditions in a plant, the content of growth inhibitors sharply increases: ethylene and abscissic acid. They reduce metabolism, inhibit growth processes, accelerate aging, fall of organs, and the transition of the plant to a dormant state. Inhibition of functional activity under stress under the influence of growth inhibitors is a characteristic reaction for plants. At the same time, the content of growth stimulants in the tissues decreases: cytokinin, auxin and gibberellins.

On the population level selection is added, which leads to the appearance of more adapted organisms. The possibility of selection is determined by the existence of intrapopulation variability in plant resistance to various environmental factors. An example of intrapopulation variability in resistance can be the unfriendly appearance of seedlings on saline soil and an increase in the variation in germination time with an increase in the action of a stressor.

A species in the modern view consists of a large number of biotypes - smaller ecological units, genetically identical, but showing different resistance to environmental factors. Under different conditions, not all biotypes are equally vital, and as a result of competition, only those of them remain that best meet the given conditions. That is, the resistance of a population (variety) to a particular factor is determined by the resistance of the organisms that make up the population. Resistant varieties have in their composition a set of biotypes that provide good productivity even in adverse conditions.

At the same time, in the process of long-term cultivation, the composition and ratio of biotypes in the population changes in varieties, which affects the productivity and quality of the variety, often not for the better.

So, adaptation includes all processes and adaptations that increase the resistance of plants to adverse environmental conditions (anatomical, morphological, physiological, biochemical, behavioral, population, etc.)

But to choose the most effective way of adaptation, the main thing is the time during which the body must adapt to new conditions.

With the sudden action of an extreme factor, the response cannot be delayed, it must follow immediately in order to exclude irreversible damage to the plant. With long-term impacts of a small force, adaptive rearrangements occur gradually, while the choice of possible strategies increases.

In this regard, there are three main adaptation strategies: evolutionary, ontogenetic and urgent. The task of the strategy is the efficient use of available resources to achieve the main goal - the survival of the organism under stress. The adaptation strategy is aimed at maintaining the structural integrity of vital macromolecules and the functional activity of cellular structures, maintaining vital activity regulation systems, and providing plants with energy.

Evolutionary or phylogenetic adaptations(phylogeny - the development of a biological species in time) - these are adaptations that arise during the evolutionary process on the basis of genetic mutations, selection and are inherited. They are the most reliable for plant survival.

Each species of plants in the process of evolution has developed certain needs for the conditions of existence and adaptability to the ecological niche it occupies, a stable adaptation of the organism to the environment. Moisture and shade tolerance, heat resistance, cold resistance and other ecological features of specific plant species were formed as a result of long-term action of the relevant conditions. Thus, heat-loving and short-day plants are characteristic of southern latitudes, less heat-demanding and long-day plants are characteristic of northern latitudes. Numerous evolutionary adaptations of xerophyte plants to drought are well known: economical use of water, deep-seated root system, shedding of leaves and transition to a dormant state, and other adaptations.

In this regard, varieties of agricultural plants show resistance precisely to those environmental factors against which breeding and selection of productive forms is carried out. If the selection takes place in a number of successive generations against the background of the constant influence of some unfavorable factor, then the resistance of the variety to it can be significantly increased. It is natural that the varieties bred by the Research Institute of Agriculture of the South-East (Saratov) are more resistant to drought than the varieties created in the breeding centers of the Moscow region. In the same way, in ecological zones with unfavorable soil and climatic conditions, resistant local plant varieties were formed, and endemic plant species are resistant to the stressor that is expressed in their habitat.

Characterization of the resistance of spring wheat varieties from the collection of the All-Russian Institute of Plant Industry (Semenov et al., 2005)

Variety	Origin	Sustainability
Enita	Moscow region	Medium drought resistant
Saratovskaya 29	Saratov region	drought resistant
Comet	Sverdlovsk region.	drought resistant
Karazino	Brazil	acid resistant
Prelude	Brazil	acid resistant
Kolonias	Brazil	acid resistant
Thrintani	Brazil	acid resistant
PPG-56	Kazakhstan	salt tolerant
Osh	Kyrgyzstan	salt tolerant
Surkhak 5688	Tajikistan	salt tolerant
Messel	Norway	Salt tolerant

In a natural environment, environmental conditions usually change very quickly, and the time during which the stress factor reaches a damaging level is not enough for the formation of evolutionary adaptations. In these cases, plants use not permanent, but stressor-induced defense mechanisms, the formation of which is genetically predetermined (determined).

Ontogenetic (phenotypic) adaptations are not associated with genetic mutations and are not inherited. The formation of such adaptations requires a relatively long time, so they are called long-term adaptations. One of these mechanisms is the ability of a number of plants to form a water-saving CAM-type photosynthesis pathway under conditions of water deficit caused by drought, salinity, low temperatures, and other stressors.

This adaptation is associated with the induction of expression of the phosphoenolpyruvate carboxylase gene, which is inactive under normal conditions, and the genes of other enzymes of the CAM pathway of CO2 uptake, with the biosynthesis of osmolytes (proline), with the activation of antioxidant systems, and with changes in the daily rhythms of stomatal movements. All this leads to very economical water consumption.

In field crops, for example, in corn, aerenchyma is absent under normal growing conditions. But under conditions of flooding and a lack of oxygen in the tissues in the roots, some of the cells of the primary cortex of the root and stem die (apoptosis, or programmed cell death). In their place, cavities are formed, through which oxygen is transported from the aerial part of the plant to the root system. The signal for cell death is the synthesis of ethylene.

Urgent adaptation occurs with rapid and intense changes in living conditions. It is based on the formation and functioning of shock protective systems. Shock defense systems include, for example, the heat shock protein system, which is formed in response to a rapid increase in temperature. These mechanisms provide short-term survival conditions under the action of a damaging factor and thus create the prerequisites for the formation of more reliable long-term specialized adaptation mechanisms. An example of specialized adaptation mechanisms is the new formation of antifreeze proteins at low temperatures or the synthesis of sugars during the overwintering of winter crops. At the same time, if the damaging effect of the factor exceeds the protective and reparative capabilities of the body, then death inevitably occurs. In this case, the organism dies at the stage of urgent or at the stage of specialized adaptation, depending on the intensity and duration of the extreme factor.

Distinguish specific and non-specific (general) plant responses to stressors.

Nonspecific reactions do not depend on the nature of the acting factor. They are the same under the action of high and low temperatures, lack or excess of moisture, high concentrations of salts in the soil or harmful gases in the air. In all cases, the permeability of membranes in plant cells increases, respiration is disturbed, the hydrolytic decomposition of substances increases, the synthesis of ethylene and abscisic acid increases, and cell division and elongation are inhibited.

The table shows a complex of nonspecific changes occurring in plants under the influence of various environmental factors.

Changes in physiological parameters in plants under the influence of stressful conditions (according to G.V., Udovenko, 1995)

Options	The nature of the change in parameters under conditions
	droughts	salinity	high temperature	low temperature
The concentration of ions in tissues	growing	growing	growing	growing
Water activity in the cell	Falling down	Falling down	Falling down	Falling down
Osmotic potential of the cell	growing	growing	growing	growing
Water holding capacity	growing	growing	growing	—
Water scarcity	growing	growing	growing	—
Protoplasm permeability	growing	growing	growing	—
Transpiration rate	Falling down	Falling down	growing	Falling down
Transpiration efficiency	Falling down	Falling down	Falling down	Falling down
Energy efficiency of breathing	Falling down	Falling down	Falling down	—
Breathing intensity	growing	growing	growing	—
Photophosphorylation	Decreases	Decreases	—	Decreases
Stabilization of nuclear DNA	growing	growing	growing	growing
Functional activity of DNA	Decreases	Decreases	Decreases	Decreases
Proline concentration	growing	growing	growing	—
Content of water-soluble proteins	growing	growing	growing	growing
Synthetic reactions	Suppressed	Suppressed	Suppressed	Suppressed
Ion uptake by roots	Suppressed	Suppressed	Suppressed	Suppressed
Transport of substances	Depressed	Depressed	Depressed	Depressed
Pigment concentration	Falling down	Falling down	Falling down	Falling down
cell division	slows down	slows down	—	—
Cell stretch	Suppressed	Suppressed	—	—
Number of fruit elements	Reduced	Reduced	Reduced	Reduced
Organ aging	Accelerated	Accelerated	Accelerated	—
biological harvest	Downgraded	Downgraded	Downgraded	Downgraded

Based on the data in the table, it can be seen that the resistance of plants to several factors is accompanied by unidirectional physiological changes. This gives reason to believe that an increase in plant resistance to one factor may be accompanied by an increase in resistance to another. This has been confirmed by experiments.

Experiments at the Institute of Plant Physiology of the Russian Academy of Sciences (Vl. V. Kuznetsov and others) have shown that short-term heat treatment of cotton plants is accompanied by an increase in their resistance to subsequent salinization. And the adaptation of plants to salinity leads to an increase in their resistance to high temperatures. Heat shock increases the ability of plants to adapt to the subsequent drought and, conversely, in the process of drought, the body's resistance to high temperature increases. Short-term exposure to high temperatures increases resistance to heavy metals and UV-B radiation. The preceding drought favors the survival of plants in conditions of salinity or cold.

The process of increasing the body's resistance to a given environmental factor as a result of adaptation to a factor of a different nature is called cross-adaptation.

To study the general (nonspecific) mechanisms of resistance, of great interest is the response of plants to factors that cause water deficiency in plants: salinity, drought, low and high temperatures, and some others. At the level of the whole organism, all plants react to water deficiency in the same way. Characterized by inhibition of shoot growth, increased growth of the root system, the synthesis of abscisic acid, and a decrease in stomatal conductance. After some time, the lower leaves rapidly age, and their death is observed. All these reactions are aimed at reducing water consumption by reducing the evaporating surface, as well as by increasing the absorption activity of the root.

Specific reactions are reactions to the action of any one stress factor. So, phytoalexins (substances with antibiotic properties) are synthesized in plants in response to contact with pathogens (pathogens).

The specificity or non-specificity of responses implies, on the one hand, the attitude of a plant to various stressors and, on the other hand, the characteristic reactions of plants of different species and varieties to the same stressor.

The manifestation of specific and nonspecific responses of plants depends on the strength of stress and the rate of its development. Specific responses occur more often if the stress develops slowly, and the body has time to rebuild and adapt to it. Nonspecific reactions usually occur with a shorter and stronger effect of the stressor. The functioning of non-specific (general) resistance mechanisms allows the plant to avoid large energy expenditures for the formation of specialized (specific) adaptation mechanisms in response to any deviation from the norm in their living conditions.

Plant resistance to stress depends on the phase of ontogeny. The most stable plants and plant organs in a dormant state: in the form of seeds, bulbs; woody perennials - in a state of deep dormancy after leaf fall. Plants are most sensitive at a young age, since growth processes are damaged in the first place under stress conditions. The second critical period is the period of gamete formation and fertilization. The effect of stress during this period leads to a decrease in the reproductive function of plants and a decrease in yield.

If stress conditions are repeated and have a low intensity, then they contribute to the hardening of plants. This is the basis for methods for increasing resistance to low temperatures, heat, salinity, and an increased content of harmful gases in the air.

Reliability of a plant organism is determined by its ability to prevent or eliminate failures at different levels of biological organization: molecular, subcellular, cellular, tissue, organ, organismal and population.

To prevent disruptions in the life of plants under the influence of adverse factors, the principles redundancy, heterogeneity of functionally equivalent components, systems for the repair of lost structures.

The redundancy of structures and functionality is one of the main ways to ensure the reliability of systems. Redundancy and redundancy has multiple manifestations. At the subcellular level, the reservation and duplication of genetic material contribute to the increase in the reliability of the plant organism. This is provided, for example, by the double helix of DNA, by increasing the ploidy. The reliability of the functioning of the plant organism under changing conditions is also supported by the presence of various messenger RNA molecules and the formation of heterogeneous polypeptides. These include isoenzymes that catalyze the same reaction, but differ in their physicochemical properties and the stability of the molecular structure under changing environmental conditions.

At the cellular level, an example of redundancy is an excess of cellular organelles. Thus, it has been established that a part of the available chloroplasts is sufficient to provide the plant with photosynthesis products. The remaining chloroplasts, as it were, remain in reserve. The same applies to the total chlorophyll content. The redundancy also manifests itself in a large accumulation of precursors for the biosynthesis of many compounds.

At the organismic level, the principle of redundancy is expressed in the formation and laying at different times of more shoots, flowers, spikelets than is required for the change of generations, in a huge amount of pollen, ovules, seeds.

At the population level, the principle of redundancy is manifested in a large number of individuals that differ in resistance to a particular stress factor.

Repair systems also work at different levels - molecular, cellular, organismal, population and biocenotic. Reparative processes go with the expenditure of energy and plastic substances, therefore, reparation is possible only if a sufficient metabolic rate is maintained. If metabolism stops, then reparation also stops. In extreme conditions of the external environment, the preservation of respiration is especially important, since it is respiration that provides energy for reparation processes.

The reductive ability of cells of adapted organisms is determined by the resistance of their proteins to denaturation, namely, the stability of the bonds that determine the secondary, tertiary, and quaternary structure of the protein. For example, the resistance of mature seeds to high temperatures is usually associated with the fact that, after dehydration, their proteins become resistant to denaturation.

The main source of energy material as a substrate for respiration is photosynthesis, therefore, the energy supply of the cell and related reparation processes depend on the stability and ability of the photosynthetic apparatus to recover from damage. To maintain photosynthesis under extreme conditions in plants, the synthesis of thylakoid membrane components is activated, lipid oxidation is inhibited, and the plastid ultrastructure is restored.

At the organismic level, an example of regeneration is the development of replacement shoots, the awakening of dormant buds when growth points are damaged.

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