Adaptations of their classification are examples. Classification of adaptations of living systems. Factors driving the need for change

Adaptation: “concept and meaning”

The result of natural selection - the differentiated survival of biological beings - contributes to the development of adaptation. The term Adaptation can have three semantic shades. In the first case, there is adaptation as a process by which the organism changes and adapts to environmental conditions. The second meaning concerns the actual relationship between an organism and its environment. In the third sense, adaptation means the degree of correspondence between an organism and its environment.

Adaptation is achieved through changes in a number of biological characteristics: biochemical, physiological, morphological and behavioral. All these are ways of adapting the body to the demands of the environment.

Adaptation can be a genetically determined process that occurs in response to the requirements of natural selection, or a phenotypic reaction of an individual that occurs during its life in response to certain environmental factors.

In a broad sense, adaptation refers to the harmony of organisms with their environment.

In a narrow sense, adaptation refers to special properties that can ensure the survival and reproduction of organisms in a specific environment.

Adaptation to some environmental factors will not necessarily remain an adaptation in other conditions.

The appearance in a population and biogeocenosis of a new successful phenotype or individuals - carriers of successful mutations - cannot yet be considered as adaptation. The emergence of a selectively valuable genotype is an elementary adaptive phenomenon. We can talk about adaptation only after the emergence of a specialized trait in a population (species) to the elements of the environment. This is achieved when selection “picks up” an elementary adaptive phenomenon and permanently changes the genotypic composition of the population. Adaptations do not appear ready-made, but are formed in the process of multi-stage selection of successful options from many changed individuals over a series of generations.

In an evolutionary sense, the concept of “adaptation” should refer not so much to an individual, but to a population and species. Changes within an individual in response to certain environmental changes occur within the limits of the reaction norm inherited by each individual.

Classification of adaptations:

Based on their origin, they distinguish between pre-adaptive, combinatorial and post-adaptive adaptations.

When pre-adaptation potential adaptation phenomena arise ahead of existing conditions. The mutation process and crossings lead to the accumulation of a hidden reserve of hereditary variability in populations. In the preadaptive way of the emergence of adaptations, previous characteristics of the organism that arose in other conditions are often successfully used. Moreover, some complex adaptations may arise “ahead” of the conditions under which they would turn out to be adaptations.

When adaptations occur in a combinative way The interaction of new mutations with each other and with the genotype as a whole is significant. The effect of mutations depends on the genotypic environment into which they will be included in the future. Crossing individuals produces a varied combination of the mutant allele with other alleles of the same and other genes. This leads to a change in the effect of the mutation through the interaction of genes. In this case, there may be either an increase or suppression of its expression in the phenotype. In all cases, a real opportunity is created for the rapid replacement of one adaptation by another. The combinative way of forming adaptation is apparently the most common in nature.

Post-adaptive path The emergence of adaptations is associated with the reduction of a previously developed trait and the use of a pre-existing organ for other purposes - not those that determined its appearance. In the post-adaptive path, new adaptations arise through the use of pre-existing structures in the event of a change in their functions. When genes that influence the development of reduced organs are transferred to a recessive state, they are included in the hidden reserve of hereditary variability. These genes are retained in the gene pool of the population and can be expressed phenotypically from time to time. If selection establishes a positive connection between such genes and new environmental conditions, they can give rise to the development of new traits and properties.

Speaking about adaptation, one cannot fail to mention its various scales. There are specialized and general adaptations.

Specialized adaptations are suitable in the narrowly localized living conditions of a species.

While the general ones are suitable in a wide range of environmental conditions.

Initially, general adaptations arise as specialized ones. Promising general adaptations affect not just one, but many organ systems.

Since adaptation is a complex and diverse phenomenon, in biological science there are several dozen classifications of adaptations, which are based on a variety of characteristics

Adaptations are also divided into organismal and species. Organismal adaptations, in turn, are divided into morphological, physiological, biochemical and ethological.

Morphological adaptations are manifested in structural advantages, protective coloration, warning coloration, mimicry, camouflage, and adaptive behavior.

The advantages of the structure are the optimal proportions of the body, the location and density of hair or feathers, etc. The appearance of an aquatic mammal, the dolphin, is well known. His movements are easy and precise. The independent speed of movement in water reaches 40 kilometers per hour. The density of water is 800 times higher than the density of air. How does a dolphin manage to overcome it? In addition to other structural features, the body shape contributes to the dolphin’s ideal adaptation to its environment and lifestyle. The torpedo-shaped body shape avoids the formation of turbulence in water flows flowing around the dolphin.

The streamlined shape of the body facilitates the rapid movement of animals in the air. The flight and contour feathers covering the bird's body completely smooth out its shape. Birds do not have protruding ears; they usually retract their legs in flight. As a result, birds are far superior to all other animals in their speed of movement. For example, the peregrine falcon dives at its prey at speeds of up to 290 kilometers per hour. Birds move quickly even in water. An chinstrap penguin was observed swimming underwater at a speed of about 35 kilometers per hour.

In animals that lead a secretive, hidden lifestyle, adaptations that give them a resemblance to objects in the environment are useful. The bizarre body shape of fish that live in algae thickets (rag-picker seahorse, clown fish, pipefish, etc.) helps them successfully hide from enemies. Similarity to objects in their environment is widespread among insects. There are known beetles whose appearance resembles lichens, cicadas, similar to the thorns of the bushes among which they live. Stick insects look like a small brown or green twig, and orthoptera insects imitate a leaf. Fish that lead a bottom-dwelling lifestyle (for example, flounder) have a flat body.

The protective coloring allows you to be invisible among the surrounding background. Thanks to the protective coloration, the organism becomes difficult to distinguish and, therefore, protected from predators. Bird eggs laid on sand or ground are gray and brown with spots, similar to the color of the surrounding soil. In cases where eggs are inaccessible to predators, they are usually colorless. Butterfly caterpillars are often green, the color of the leaves, or dark, the color of the bark or earth. Bottom fish are usually colored to match the color of the sandy bottom (rays and flounder). Moreover, flounders also have the ability to change color depending on the color of the surrounding background. The ability to change color by redistributing pigment in the integument of the body is also known in terrestrial animals (chameleon). Desert animals, as a rule, have a yellow-brown or sandy-yellow color. A monochromatic protective color is characteristic of both insects (locusts) and small lizards, as well as large ungulates (antelope) and predators (lion).

If the background of the environment does not remain constant depending on the season of the year, many animals change color. For example, inhabitants of middle and high latitudes (arctic fox, hare, ermine, white partridge) are white in winter, which makes them invisible in the snow.

A variant of protective coloring is dismembering coloring in the form of alternating light and dark stripes and spots on the body. Zebras and a tiger are difficult to see even at a distance of 40-50 meters due to the coincidence of the stripes on the body with the alternation of light and shadow in the surrounding area. Dismembering coloring disrupts ideas about the contours of the body.

Warning (threatening) coloring warns a potential enemy of the presence of defense mechanisms (the presence of toxic substances or special defense organs). Warning coloring distinguishes poisonous, stinging animals and insects (snakes, wasps, bumblebees) from the environment with bright spots or stripes.

The effectiveness of warning coloration gave rise to a very interesting phenomenon - imitation (mimicry). Mimicry is the similarity in color and body shape of safe animals with poisonous and dangerous animals. Certain species of flies that do not have a sting are similar to stinging bumblebees and wasps, and non-venomous snakes are similar to poisonous ones. In all cases, the similarity is purely external and is aimed at forming a certain visual impression among potential enemies. There are now two main types of mimicry known: Batesian mimicry and Müllerian mimicry.

In Batesian mimicry, the model is well protected and usually has bright, warning colors. With Müllerian mimicry, two or more inedible species turn out to be similar: as a result of their similarity, the predator is more likely to wean itself from grasping such animals. The first type of mimicry can be compared to a small company imitating the advertising of some well-known large company. The second type is comparable to several companies that use general advertising to save money. An example of Bates's mimicry: often hidden under the guise of wasps are defenseless flies whose body shape and yellow-black coloration imitate wasps (syrphid flies and bighead flies). An example of Müllerian mimicry: some species of cabbage white butterflies are similar to the inedible South American heliconids.

Mimicry is the result of homologous (identical) mutations in different species that help unprotected animals survive. For imitating species, it is important that their numbers are small compared to the model they are imitating, otherwise the enemies will not develop a stable negative reflex to the warning coloration. The low abundance of mimicking species is supported by a high concentration of lethal genes in the gene pool. When homozygous, these genes cause lethal mutations, resulting in a high percentage of individuals not surviving to adulthood.

In addition to protective coloring, other means of protection are observed in animals and plants. Plants often develop needles and spines that protect them from being eaten by herbivores (cacti, rose hips, hawthorn, sea buckthorn, etc.). The same role is played by toxic substances that burn hairs, for example in nettles. Crystals of calcium oxalate, which accumulate in the thorns of some plants, protect them from being eaten by caterpillars, snails and even rodents. Formations in the form of a hard chitinous cover in arthropods (beetles, crabs), shells in mollusks, scales in crocodiles, shells in armadillos and turtles protect them well from many enemies. The quills of hedgehogs and porcupines serve the same purpose. All these adaptations could only appear as a result of natural selection, i.e. preferential survival of better protected individuals.

Camouflage is a device in which the body shape and color of animals merge with surrounding objects. For example, in tropical forests, many snakes are indistinguishable among the vines, a shaggy seahorse looks like algae, insects on tree bark look like lichens (beetles, longhorned beetles, spiders, butterflies). Sometimes adaptation to the color and pattern of the substrate can be carried out through a physiological change in body color (cuttlefish, stingrays, flounder, tree frogs) or a change in color during the next molt (grasshoppers).

The protective effect of protective coloring or body shape increases when combined with appropriate behavior. Adaptive behavior is the adoption of certain resting poses (the caterpillars of some insects in a motionless state are very similar to a tree knot; the callima butterfly with folded wings surprisingly resembles a dry leaf of a tree), or, conversely, demonstrative behavior that scares off predators. In addition to hiding or demonstrative, scaring behavior when an enemy approaches, there are many other options for adaptive behavior that ensure the survival of adults or juveniles. This includes storing food for the unfavorable season of the year. This is especially true for rodents. For example, the root vole, common in the taiga zone, collects cereal grains, dry grass, roots - up to 10 kilograms in total. Burrowing rodents (mole rats, etc.) accumulate pieces of oak roots, acorns, potatoes, steppe peas - up to 14 kilograms. The large gerbil, living in the deserts of Central Asia, cuts grass at the beginning of summer and drags it into holes or leaves it on the surface in the form of stacks. This food is used in the second half of summer, autumn and winter. The river beaver collects cuttings of trees, branches, etc., which it places in the water near its home. These warehouses can reach a volume of 20 cubic meters. Predatory animals also store food. Mink and some ferrets store frogs, snakes, small animals, etc. An example of adaptive behavior is the time of greatest activity. In deserts, many animals go hunting at night, when the heat subsides.

Physiological adaptations are the acquisition of specific metabolic features in different environmental conditions. They provide functional benefits to the body. They are conventionally divided into static (constant physiological parameters - temperature, water-salt balance, sugar concentration, etc.) and dynamic (adaptation to fluctuations in the action of a factor - changes in temperature, humidity, light, magnetic field, etc.).

The appropriate shape and coloring of the body, appropriate behavior ensure success in the struggle for existence only when these characteristics are combined with the adaptability of life processes to living conditions, i.e. with physiological adaptation. Without such adaptation, it is impossible to maintain a stable metabolism in the body in constantly fluctuating environmental conditions. Let's give some examples.

Plants living in semi-desert and desert areas have numerous and varied adaptations. This includes a root that goes tens of meters deep into the earth, extracting water, and a sharp decrease in water evaporation due to the special structure of the cuticle on the leaves, and the complete loss of leaves. In cacti, this transformation is especially surprising: the transformation of the stem not only into an organ that performs supporting and conducting functions, but also into a structure that stores water and ensures photosynthesis. Large specimens of cacti accumulate up to 2000 liters of water. It is consumed slowly, since the cell sap also contains, along with organic acids and sugars, mucous substances that have water-retaining properties. Even after a three-month drought, prickly pear stems contained almost 81% water. Water evaporation is significantly reduced due to the ribbed structure of the cactus stems, which evenly distributes light and shadow. This is also facilitated by the thickening of the walls of the epidermis, usually covered with a layer of wax, the presence of numerous spines and hairs, and much more.

In terrestrial amphibians, large amounts of water are lost through the skin. However, many of their species penetrate even into deserts and semi-deserts. The survival of amphibians in conditions of lack of moisture in these habitats is ensured by a number of adaptations. Their activity pattern changes: it coincides with periods of high humidity. In the temperate zone, toads and frogs are active at night and after rainfall. In deserts, frogs hunt only at night, when moisture condenses on the soil and vegetation, and during the day they hide in rodent burrows. In desert amphibian species that breed in temporary reservoirs, the larvae develop very quickly and undergo metamorphosis in a short time.

Birds and mammals have developed various mechanisms of physiological adaptation to unfavorable conditions. Many desert animals accumulate a lot of fat before the onset of the dry season: when it oxidizes, a large amount of water is formed. Birds and mammals are able to regulate water loss from the surface of the respiratory tract. For example, a camel, when deprived of water, sharply reduces evaporation both from the respiratory tract and through the sweat glands.

A person's salt metabolism is poorly regulated, and therefore he cannot do without fresh water for a long time. But reptiles and birds, which spend most of their lives in the sea and drink sea water, have acquired special glands that allow them to quickly get rid of excess salts.

The adaptations that develop in diving animals are very interesting. Many of them can survive for a relatively long time without access to oxygen. For example, seals dive to a depth of 100-200 and even 600 meters and stay under water for 40-60 minutes. What allows pinnipeds to dive for such a long period of time? This is, first of all, a large amount of a special pigment found in the muscles - myoglobin. Myoglobin is capable of binding 10 times more oxygen than hemoglobin. In addition, in water, a number of devices ensure much more economical consumption of oxygen than when breathing on the surface.

Through natural selection, adaptations arise and improve that make it easier to find food or a partner for reproduction. The chemical sense organs of insects are amazingly sensitive. Male gypsy moths are attracted to the scent of a female's scent gland from a distance of 3 kilometers. In some butterflies, the sensitivity of taste receptors is 1000 times greater than the sensitivity of the receptors of the human tongue. Nocturnal predators, such as owls, have excellent vision in low-light conditions. Some snakes have well-developed thermolocation abilities. They distinguish objects at a distance if their temperature difference is only 0.2°C. Many animals perfectly navigate in space using echolocation (bats, owls, dolphins).

Biochemical adaptations ensure the optimal course of biochemical reactions in the cell, for example, the ordering of enzymatic catalysis, the specific binding of gases by respiratory pigments, the synthesis of necessary substances under certain conditions, etc.

Ethological adaptations represent all behavioral responses aimed at the survival of individuals and, therefore, the species as a whole. Such reactions are:

behavior when searching for food and a sexual partner,

pairing,

feeding offspring

avoiding danger and protecting life in the event of a threat,

aggression and threatening postures,

gentleness and many others.

Some behavioral reactions are inherited (instincts), others are acquired throughout life (conditioned reflexes). In different organisms the ratio of instinctive and conditioned reflex behavior is not the same. For example, in invertebrates and lower chordates, instinctive behavior predominates, and in higher mammals (primates, carnivores), conditioned reflex behavior predominates. Humans have the highest level of behavioral adaptability, based on the mechanisms of higher nervous activity.

Particularly important are adaptations that protect the offspring from enemies.

Species adaptations are discovered when analyzing a group of individuals of the same species; they are very diverse in their manifestation. The main ones are various congruences, the level of mutability, intraspecific polymorphism, the level of abundance and optimal population density.

Congruences represent all morphophysiological and behavioral features that contribute to the existence of a species as an integral system. Reproductive congruences ensure reproduction. Some of them are directly related to reproduction (correspondence of genital organs, adaptations to feeding, etc.), while others are only indirect (various signal signs: visual - mating attire, ritual behavior; sound - birdsong, roar of a male deer during the rut and etc.; chemical - various attractants, for example, insect pheromones, secretions from artiodactyls, cats, dogs, etc.).

Congruences include all forms of intraspecific cooperation - constitutional, trophic and reproductive. Constitutional cooperation is expressed in the coordinated actions of organisms in unfavorable conditions, which increase the chances of survival. In winter, bees gather in a ball, and the heat they generate is spent on joint warming. In this case, the highest temperature will be in the center of the ball and individuals from the periphery (where it is colder) will constantly strive there. In this way, the insects constantly move and, through joint efforts, they survive the winter safely. Penguins also cluster in a close group during incubation, sheep during cold weather, etc.

Trophic cooperation consists of the union of organisms for the purpose of obtaining food. Joint activity in this direction makes the process more productive. For example, a pack of wolves hunts much more efficiently than an individual. At the same time, in many species there is a division of responsibilities - some individuals separate the chosen victim from the main herd and drive it into ambush, where their relatives are hiding, etc. In plants, such cooperation is expressed in joint shading of the soil, which helps retain moisture in it.

Reproductive cooperation increases reproductive success and promotes the survival of offspring. In many birds, individuals gather on lekking grounds, and in such conditions it is easier to find a potential partner. The same thing happens at spawning grounds, rookeries of pinnipeds, etc. The likelihood of pollination in plants increases when they grow in groups and the distance between individual individuals is small.

Mutability is the frequency of mutations per unit of time (number of generations) and per gene. Each species has its own frequency, which is determined by the level of stability of the genetic material and resistance to mutagens. Mutations make populations heteromorphic and provide material for selection. Both excessively high and insufficient mutability are dangerous for the species. In the first case, there is a threat to the integrity of the species, and in the second, selection is impossible.

Intraspecific polymorphism determines the unique combination of alleles in different individuals. The cause of polymorphism is sexual reproduction, which provides combinative variability, and mutations that change the substrate of heredity. Maintaining intraspecific polymorphism ensures the stability of the species and guarantees its existence in various environmental conditions.

The population level determines the extreme values ​​of the number of individuals of a species. A decrease in numbers below a threshold level leads to the death of the species. This is due to the impossibility of meeting partners, disruption of intraspecific adaptation, etc. An excessive increase in numbers is also detrimental, since it undermines the food supply, contributes to the accumulation of sick and weakened individuals in the population, and in some this leads to the development of stress.

The optimal population density shows the specific features of the coexistence of individuals for each species. Many organisms prefer a solitary lifestyle and meet only to mate. This is how, for example, tigers, leopards, male elephants, etc. behave. Others have a strong instinct for collectivity, so they need high numbers. For example, the most numerous groups among vertebrates were formed by American passenger pigeons, whose flocks numbered billions (!) of individuals. After their numbers were undermined by humans, passenger pigeons stopped reproducing and the species disappeared.

One of the most important problems of modern physiology is the identification of the physiological mechanisms underlying adaptation - the adaptation of the organism to environmental agents affecting it or to changes in the physiological state.

Physiological adaptation should be understood as a set of physiological characteristics that determine the balance of the organism with constant or changing environmental conditions. Depending on the duration and frequency of these changes, adaptations can be cyclical and more or less persistent. The very term “adaptation” characterizes only the phenomenology of the phenomenon and does not imply any explanation of the mechanisms underlying it.

In recent years, several classifications of physiological adaptations have been proposed. These classifications usually take into account the stages of development of the process and, depending on this, include the question of its reversibility.

Hensel and Hildebrandt (Hensel a. Hildebrandt, 1964) propose a classification of adaptation based on the time of exposure to the body. They distinguish three types of adaptation:

1. Acute changes in the regulation of functions that occur in response to external or internal changes, lasting from several seconds to several minutes, and sometimes hours.

2. Weak adaptive responses of the body to changes in the external environment; they include the concepts of acclimation and acclimatization. The duration of these shifts ranges from hours or months to several years.

3. Adaptation in the evolutionary aspect - the transformation and selection of genetically adapted types - is an extremely slow process, involving a number of generations and stretched over millions of years.

With this classification, the authors tried to replace the classification of the Canadian physiologist Hart (Hart, 1955), also dividing (in relation to the effects of cold) all phenomena into acclimation - an acute and reversible process; acclimatization is a process that occurs throughout an individual’s life; and adaptation is a process that lasts for many generations.

However, these classifications do not provide an analysis of the origin of adaptation in onto- and phylogeny, and most importantly, they do not propose to separate their innate elements from those acquired during an individual’s life.

In order to study natural adaptations (Slonim, 1962), a classification of adaptations was proposed depending on their origin in onto- and phylogenesis and on their significance for the life of an individual, population or species as a whole. Based on the presence of congenital and hereditary elements in adaptation, as well as elements acquired in the process of individual development, it was proposed to divide all adaptation phenomena into three groups.

First group phenomena includes individual adaptations that occur during postnatal development. This includes the formation of conditioned reflexes and more complex stereotypes that arise when environmental factors influence an adult organism. These phenomena may be of a slightly different nature when exposed to certain, mainly early stages of postembryonic development (see page 74). The group of individual adaptations should also include changes in hormonal relationships (such as stress, nonspecific adaptation phenomena) and tissue processes. All these changes in the body (especially with relatively short exposures) are practically reversible and relatively easy to detect experimentally.

Second group phenomena includes species-specific, hereditarily fixed adaptations. They are caused by the hereditarily fixed characteristics of the nervous system and hormonal and tissue regulations and, to a large extent, by the entire dynamics of morphological changes that arose during the ontogenesis of an individual of a given species. These adaptations cover individual organ systems with the replacement of one organ and system by another characteristic of each type of adaptation.

Adaptive features of innate acts of behavior ensure in higher organisms contact with the nursing female during the nesting period of development, patterns of settlement of young animals (collapse of the nest and nesting relationships), etc. These hereditarily programmed reflex acts and complex hormonal relationships are very specialized and vary greatly even among close relatives in taxonomic terms of species. The adaptive significance of such physiological reactions when compared with environmental factors is usually beyond doubt. They constitute the main fund of knowledge in the field of environmental physiology.

Third group - population adaptations arise in the process of formation of a population in the given specific conditions of its existence. The study of these adaptations and the dynamics of their formation is of the greatest interest for ecology as a whole, since it characterizes the behavior of the species in different conditions of existence. Population adaptations are very complex in their genetic structure. They reflect hereditary forms of adaptation and the environmental influences superimposed on them at all stages of both prenatal and postnatal development, including the phenomena of imprinting (see Chap. III). In addition, they include, of course, all strictly genetic relationships associated with natural (and sometimes artificial) selection.

Adaptive changes in physiological reactions that occur in response to the influence of various environmental factors may depend on the characteristics of the structure and function of body cells, entire organ systems and, finally, regulations associated with maintaining the general level of physiological reactions of the animal.

One of the main features of adaptation as a process that allows an organism to continue to exist in a changed environment is the maintenance of vital activity and certain aspects of homeostasis characteristic of organisms of a given species, a given level of development of its nervous and hormonal mechanisms. In accordance with the evolutionary level of development of an animal, we can talk about different types of adaptation, covering different levels of regulated systems - cellular, tissue, organ and the level of the whole organism. In the latter case, the adaptation process involves, in addition to changes in the autonomic functions themselves, changes in motor behavior.

The most important adaptations of organisms to environmental conditions are thermal, osmotic, redox and nutritional (enzymatic). They are characteristic of essentially all living beings without exception, including plant organisms.

However, in terms of their mechanisms, adaptive changes in physiological functions can be quite clearly differentiated depending on the presence of certain homeostatic mechanisms. This allows us to separate the adaptation features of homoyo- and poikilothermic organisms, homoyo- and poikiloosmotic organisms, aquatic and terrestrial organisms, etc.

The process of evolution of living beings over several million years included "chemical evolution" (Prosser, 1964). During this period, organisms acquired the ability to use the high potential energy of phosphates in the metabolic process, genetic coding using nucleic acids, specific proteins as catalysts (enzyme systems), selective permeability of cell membranes, and selective ability to retain individual ions (potassium). It is these tissue mechanisms for maintaining life at the cellular level that formed the basis for the adaptive evolution of organisms.

However, the levels at which these elementary chemical mechanisms are used can be quite different. In addition to organismal levels of regulation, there are also “supraorganismal” ones.

In accordance with the dependence of the vital activity of the organism on a given environmental factor, one can distinguish between “dependent” organisms (conforming organisms) and “regulating” (regulating organisms). The difference between “dependent” and “regulating” organisms can best be detected by comparing the dependence of the intensity of general metabolism on the temperature surrounding the organism. The higher the temperature of the environment (up to a certain critical limit), the more intense the metabolism of a poikilothermic organism. Along with the temperature of the environment, body temperature also increases. However, with prolonged exposure to high temperatures, adaptation occurs. Metabolism increases somewhat less. In homeothermic organisms, against the background of a constant but reduced metabolism, a constant body temperature is also observed.

Adaptation takes place in both cases, but in homeotherms it manifests itself at the level of the whole organism (thermoregulation), and in poikilothermic organisms - at the level of cellular systems.

Tissue adaptations in mammals and birds are found in relation to fluctuations in tissue temperature, oxygen supply, water content and ionic composition, and carbon dioxide content. In addition, the resistance of certain organisms to poisons undoubtedly has a cellular nature (for example, the resistance of insectivores to snake venom, etc.).

Tissue adaptations to lower temperatures are most pronounced. To this day, it remains a mystery how the limbs of seabirds (gulls, cormorants, penguins, etc.) without any thermal insulation do not freeze at very low air temperatures. How is tissue metabolism carried out, the release of oxygen from the blood in tissue capillaries at temperatures close to 0°C, and sometimes below 0°C, when all tissue enzymatic systems are inactive, and oxyhemoglobin of homeothermic organisms is not capable of releasing oxygen even at high CO 2 voltages. Many of these questions cannot currently be given a sufficiently convincing answer, but the study of adaptive changes in cellular systems itself opens up broad prospects for understanding the physiological mechanism of environmental adaptation in animals.

- Source-

Slonim, A.D. Ecological physiology of animals/ A.D. Slonim. - M.: Higher School, 1971. - 448 p.

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An employee's entry into a new position is inevitably accompanied by an adaptation process. As already noted, adaptation means an individual’s adaptation to the workplace, work and work team and reflects the state that each of us experiences when entering a new, unknown environment.

From the point of view of personnel management in the organization adaptation has a dual focus .

1. On the one hand, the newcomer gets acquainted with the team, new responsibilities and working conditions, tries to understand and accept them.

2. On the other hand, the organization itself changes and adapts to the characteristics of the employee.

In this regard, A.P. Egorshin distinguishes two adaptation processes :

1. personnel adaptation . Personnel adaptation is the process of adapting the team to the changing conditions of the external and internal environment of the organization.

2. employee adaptation . Adaptation of an employee is the adaptation of an individual to the workplace and work collective.

Thus, when a new employee joins an organization, two simultaneous processes of adaptation are observed. Therefore, the adaptation process can be defined as the mutual adaptation of the employee and the organization. And the possibility of long-term cooperation depends on how successful this adaptation is.

Like any management phenomenon, adaptation has its own specific characteristics, which formed the basis of its classifications. Distinguish several types of adaptation .

Discharge is widespread

- primary adaptation. Primary adaptation is understood as the adaptation of persons who do not have work experience, i.e. when a person first starts V work activity.

- secondary adaptation. Secondary - adaptation of workers during a subsequent job change.

However, the works of some authors say that primary adaptation occurs in the case of a newly hired employee, when the candidate goes to work for the first time in a specific organization, and secondary adaptation occurs when the employee moves to another position or to another department.

It should be noted that in the conditions of formation and functioning of the labor market, the role of secondary adaptation increases. At the same time, we must not forget about the initial adaptation of young employees, since they represent a very interesting category of the workforce. This group of specialists can be extremely useful for the employer in conditions of shortage of workers in many professions, but at the same time needs V increased attention and care from the administration.

The following classification is based on division into types of adaptation depending on the object to which the employee
adapts.

As can be seen from the figure, in relation to the object, types of adaptation can be divided into two main groups:

1.production

2.non-production. As the name suggests, non-work adaptation refers to areas of an employee’s life that are not directly related to their work.

Rice. Types of adaptation

Production adaptation includes all aspects of employee adaptation to work in a new organization, namely:

1. Professional adaptation .

Professional adaptation - this is the adaptation of the employee to the work performed. It consists in familiarizing and actively mastering the profession, its intricacies, specifics, acquiring professional skills sufficient for high-quality performance of duties, in the formation of some professionally necessary personality qualities, in the development of a stable positive attitude of the employee towards his profession.

Professional adaptation plays a big role in the situation of a young specialist entering an organization, since he has a mainly theoretical understanding of how the work process occurs. Professional adaptation assessed by both objective and subjective indicators.

Objective indicators include :

Fulfillment of job duties and production standards;

Employee qualifications;

Availability of special knowledge and skills.

To subjective indicators relate:

Motives for choosing the procession;

Emotional assessment;

Plans for changing and maintaining the profession.

2. Psychophysiological adaptation.

Psychophysiological adaptation- This adaptation to “work activity at the level of the worker’s body as a whole, resulting in smaller changes in its functional state.”

It involves getting used to working conditions and work schedules, and establishing a normal level of working capacity. This type of adaptation depends on a person’s health, his natural reactions and individual biorhythms, as well as on working conditions. Despite the apparent simplicity of this element of adaptation, it should be borne in mind that most industrial accidents occur in the first days of an employee’s work precisely because of its absence.

3. Socio-psychological adaptation.

Socio-psychological adaptation- adaptation of the newcomer to the team. It consists of mastering the socio-psychological characteristics of groups and individuals in an organization, entering into the existing system of relationships, positive interaction with other members and getting used to a new leadership style. This means the inclusion of the employee in the system of relationships in the organization, in its team as an equal, accepted by all members.

In a situation with a young specialist who is going to work for the first time or who has little work experience, socio-psychological adaptation is not of great importance, since this category of employees has not yet developed social skills. They can easily absorb all the corporate standards of the organization, which will not be blocked by previous norms. In addition, the first place in the adaptation of young specialists is the development of professional skills, and interpersonal relationships are formed in most cases under the influence of tutelage and training by a more experienced mentor.

Different conditions arise when a professional with extensive experience in other organizations comes to a new workplace. He brings with him not only business qualities and knowledge of his business, but all the values ​​and norms that he acquired at his previous place of work. And in this case, a new person often has to “break” already existing stereotypes of relationships in the team, and a “culture conflict” may arise.

4. .

Organizational and administrative adaptation- adaptation to the existing structure of the enterprise, the peculiarities of the organizational management mechanism, the place of one’s unit and position in the general system of goals.

In our opinion, it is of particular importance for the employee to get used to the new corporate culture, leadership style, assimilate the values ​​of the organization and share its goals.

5. Economic adaptation.

Economic adaptation -getting used to a certain level of earnings and social security. It allows the employee to become familiar with the economic mechanism of managing the organization, the system of economic incentives and motives.

6.Sanitary and hygienic adaptation.

Sanitary and hygienic adaptation -adaptation to work routines, working conditions, new requirements of labor, production and technological discipline.

Non-production adaptation includes:

1. adaptation to new living conditions ;

Essay

"Anthropology: evolution and adaptation"

2004

1. Introduction: “the origins of the theory and the role of evolution”

2. Evolution and natural selection

3. Adaptation: “concept and meaning”

4. Classification of adaptations

5. Conclusion

1. Introduction: “the origins of the theory and the role of evolution”

How did man appear? The question of human origin has concerned people since time immemorial. And this is no wonder. Without knowing your own origin, it is not possible to know your own purpose, to find your own meaning, justification for your own existence. For a long time, people have been counting years and generations. History describes various centuries and aspects of events that took place. Various sciences describe the “past” reflected in various media. Archeology searches for the remains of past times in the strata of the earth's surface. History has won the title “the science of the past.” Anthropology occupies a special place.

With the evolutionary theory of Charles Darwin, the history of the search for an answer to the above question begins its new countdown. The new theory, which claims to scientifically confirm the biological origin of man, has replaced the theological theory that it was God who created man, in accordance with the lines of the Holy Scriptures. The theory of evolution, which is based on the works of Charles Darwin “The Origin of Species” and “The Descent of Man,” changed the view of subsequent generations of scientists on the immutability of the forms of all life on planet Earth.

The science of Anthropology takes its name from the Greek words anthropos - man and logos - doctrine.

The subject of anthropology is the study of variations in human physical type in space and time.

How do scientific anthropologists obtain knowledge about their subject of research? First of all, archeology helps to illuminate areas of early human history. Archaeological finds of the remains of former creatures that inhabited the earth and their tools are examined by anthropologists to determine whether they belong to a specific historical period. After which, based on many similar finds, a hypothesis is built about the history of a particular species of living beings. Of course, an important role in this is played by the rich imagination of the researcher, who is able to assume a fairly reliable course of events and try to restore it by connecting various facts together and filling in the gaps with logical reasoning and evidence.

The main role in such construction of scientific hypotheses and conclusions is played by the idea of ​​the gradual development and change of living beings, in the process of their adaptation to the natural environment.

Evolutionary theory forms the basis of the paradigm of today's science of anthropology. This is the most substantiated and evidence-based theory of the origin of all life on planet Earth.

2. Evolution and natural selection

The fact that we are very different from most other species that inhabit the Earth has greatly influenced the approach to the question of evolution. Accumulated archaeological evidence provides answers to the following questions: what did ancient hominids look like?; when did they arise?; where did they appear?; how did they evolve? But the main question is why? it remains controversial.

“Evolution is a problem-solving process,” says one of the anthropologists R. Foley. Natural selection favors those “solutions” that better cope with the tasks posed by the environment. This is how populations and species adapt to their living conditions. This means that “becoming a hominid” turned out to be the best in terms of adaptation compared to other alternatives available at that time.

The process of adaptation to the natural environment can be found recorded both in fossil remains,

and in the peculiarities of our current biology and behavior. These traits, however, were shaped by the challenges that early hominids faced.

Biological evolution is a complex phenomenon consisting of many processes, but they are based on the mechanism of natural selection. In its simplest form, the theory of evolution states that those individuals that leave more offspring than others will be genetically better represented in subsequent generations and, therefore, the latter will be especially similar to those organisms that successfully reproduced.

The strength of selection, and hence the direction and rate of evolution, is limited by the degree and nature of variation within a population. Selection operates on phenotypes, i.e. real morphological, physiological, biochemical and behavioral manifestation of the organism. The fitness of the phenotype determines the success of survival and reproduction. However, selection can only act if there is a way in which phenotypic traits can be inherited, i.e. be passed on to descendants, and, therefore, continue through a number of generations. Without this, phenotypic fitness would have no meaning. The genetic basis of life exerts a restraining influence on the force of natural selection. The fact is that the gene does not change throughout life. Information can only go in one direction - from genotype to phenotype, but not vice versa. Also, it is the gene, as part of the haploid gamete, that is transmitted from parents to children. And it is the gene that maintains the continuous course of evolution.

New genes appear in a population mainly as a result of mutations. It is mutations that maintain and increase the level of genetic variability. Features of the phenotype. The resulting mutation will depend on the nature of the original phenotype. It is this property that can ensure the constant nature of evolution. It is very important to note one circumstance that not all the consequences of the mutation will appear immediately and simultaneously. This means that the change process will take a long time.

Competition – this is a mandatory prerequisite for natural selection. It is in the light of limited resources that those individuals better suited to master them receive advantages in terms of reproduction, and therefore advantages in the process of natural selection. Hence, in order for any trait to fall under the influence of natural selection, it is necessary that this trait influence the individual’s ability to successfully reproduce. Differences in phenotypes that do not have a significant impact on the chances of survival of an individual cannot play an important role in evolution.

So, the core of evolutionary theory is the principle of natural selection. At the same time, individuals are the main material for evolution and therefore should be considered as an analytical unit of adaptive behavior. Another fact may support this conclusion. When considering the question of what is the unit of selection, it should be borne in mind that it is individuals who adapt to the environment, and not groups of them or genes.

3. Adaptation: “concept and meaning”

The result of natural selection – the differentiated survival of biological beings – contributes to the development of adaptation. The term Adaptation can have three semantic shades. In the first case, there is adaptation as a process by which the organism changes and adapts to environmental conditions. The second meaning concerns the actual relationship between an organism and its environment. In the third sense, adaptation means the degree of correspondence between an organism and its environment.

Adaptation is achieved through changes in a number of biological characteristics: biochemical, physiological, morphological and behavioral. All these are ways of adapting the body to the demands of the environment.

Adaptation can be a genetically determined process that occurs in response to the requirements of natural selection, or a phenotypic reaction of an individual that occurs during its life in response to certain environmental factors.

In a broad sense, adaptation refers to the harmony of organisms with their environment.

In a narrow sense, adaptation refers to special properties that can ensure the survival and reproduction of organisms in a specific environment.

Adaptation to some environmental factors will not necessarily remain an adaptation in other conditions.

The appearance in a population and biogeocenosis of a new successful phenotype or individuals - carriers of successful mutations - cannot yet be considered as adaptation. The emergence of a selectively valuable genotype is an elementary adaptive phenomenon. We can talk about adaptation only after the emergence of a specialized trait in a population (species) to the elements of the environment. This is achieved when selection “picks up” an elementary adaptive phenomenon and permanently changes the genotypic composition of the population. Adaptations do not appear ready-made, but are formed in the process of multi-stage selection of successful options from many changed individuals over a series of generations.

In an evolutionary sense, the concept of “adaptation” should refer not so much to an individual, but to a population and species. Changes within an individual in response to certain environmental changes occur within the limits of the reaction norm inherited by each individual.

4. Classification of adaptations:

Based on their origin, they distinguish between pre-adaptive, combinatorial and post-adaptive adaptations.

ü When pre-adaptation potential adaptation phenomena arise ahead of existing conditions. The mutation process and crossings lead to the accumulation of a hidden reserve of hereditary variability in populations. In the preadaptive way of the emergence of adaptations, previous characteristics of the organism that arose in other conditions are often successfully used. Moreover, some complex adaptations may arise “ahead” of the conditions under which they would turn out to be adaptations.

ü When adaptations occur in a combinative way The interaction of new mutations with each other and with the genotype as a whole is significant. The effect of mutations depends on the genotypic environment into which they will be included in the future. Crossing individuals produces a varied combination of the mutant allele with other alleles of the same and other genes. This leads to a change in the effect of the mutation through the interaction of genes. In this case, there may be either an increase or suppression of its expression in the phenotype. In all cases, a real opportunity is created for the rapid replacement of one adaptation by another. The combinative way of forming adaptation is apparently the most common in nature.

ü Post-adaptive path The emergence of adaptations is associated with the reduction of a previously developed trait and the use of a pre-existing organ for other purposes - not those that determined its appearance. In the post-adaptive path, new adaptations arise through the use of pre-existing structures in the event of a change in their functions. When genes that influence the development of reduced organs are transferred to a recessive state, they are included in the hidden reserve of hereditary variability. These genes are retained in the gene pool of the population and can be expressed phenotypically from time to time. If selection establishes a positive connection between such genes and new environmental conditions, they can give rise to the development of new traits and properties.

Speaking about adaptation, one cannot fail to mention its various scales. There are specialized and general adaptations.

ü Specialized adaptations are suitable in narrowly local living conditions of the species.

ü While the general ones are suitable in a wide range of environmental conditions.

Initially, general adaptations arise as specialized ones. Promising general adaptations affect not just one, but many organ systems.

5. Conclusion

In addition to the above, the following can be added regarding adaptation. The degree of perfection of a particular adaptation that appears in the process of adaptation is determined by the external environment, and therefore adaptation is always relative. Adapted to one conditions, to one level of organization, it ceases to be so in other conditions, at other levels.

And in conclusion, it should be noted that Adaptation is the tendency to optimize the correspondence between the behavior of an organism and its environment. Selection favors the “optimal solution” to problems faced by the organism.

Bibliography:

1. "Anthropology" Reader." edited by V.Yu. Bakholdina, M.A. Deryagina. M: 1997

2. "Anthropology" reader. Moscow-Voronezh: 1998 T.E.Rossolimo, L.B.Rybalov, I.A.Moskvina-Tarkhanova.