Adaptation of organisms to environmental factors. Adaptation of the body to various conditions

Adaptation(device) in itself general view can be defined as a set of adaptive reactions and morphological changes that allow the organism to maintain relative constancy internal environment in changing environmental conditions. This is an effective and economical, adequate adaptive activity of the body in relation to the influence of environmental factors. Adaptation is formed with the participation of a number of factors, in particular heredity, variability, and selection. Currently, three main ways of manifestation of adaptation have been identified. The first is active, in which regulatory processes develop, the general resistance of the body is enhanced, etc. The second path is passive, in which the basic functions of the body are subordinated to the action of environmental factors. The third way comes down to the body developing such physiological processes that allow it to avoid adverse effects.

There are three main types of adaptation: morphological, physiological and behavioral. Morphological adaptation associated with changes in the structure of the body; physiological- ensures the maintenance of its functional state, preservation and performance of the body, behavioral adaptation is closely related to the physiological and is determined by it. In addition, human adaptation is divided into genotypic and phenotypic. Genotypic adaptation is carried out in addition to human consciousness, since its mechanisms are already embedded in the genes; phenotypic adaptation always associated with conscious human activity.

According to the ideas of P.K. Anokhin, adaptation should be considered as the formation of a new functional system, which contains an adaptive effect.

Adaptation at the cellular level associated with the activation of energy and plastic processes. The main mechanism of cellular adaptation is the maintenance of the constancy of the main energy compound - ATP.

Human adaptation to environmental conditions has a pronounced social character. It is not a passive reaction of the body, but represents an active process of adaptation of all organs and systems, as well as mental activity, to the corresponding conditions of the collective.

A measure of adaptation is the level of health, which is determined by the preservation of homeostasis (the stability of the internal environment of the body) both at rest and in subextreme and extreme situations.

Adaptation, together with self-regulation, maintains the basic parameters of the body within physiological limits, increases the power of homeostatic systems that ensure stability in changing environmental conditions.

Human health as a state of an entire organism, characterized by a certain stability of homeostasis, is a multidimensional and dynamic concept. Its multidimensionality is determined various systems involved in maintaining a specific state and level of health. All of them are interconnected, subordinate, and the level of their functional activity can be expressed quantitatively.

It is advisable to highlight several parameters that determine the adaptive capabilities of the organism:

• level and harmony of physical development;
• backup capabilities of the main physiological systems;
• level of immune defense and nonspecific resistance (resistance) of the body;
• presence (or absence) chronic disease or developmental defect;
• level of moral-volitional and value-motivational attitudes.

Depending on the degree of manifestation, these indicators can positively or negatively affect the health of the body. For example, with harmonious physical development and good reserves cardiovascular system a person may have a low level of immunity, hardiness and, as a result, frequent colds, a tendency to exacerbate an existing chronic disease.

The physical development of a person is closely related to the functional state of the body. The latter is determined by the reserve capabilities of its main systems, the activity of which depends on regulatory mechanisms. It is on the state of these mechanisms and their perfection that the effectiveness of adaptation processes in domestic and industrial conditions, as well as in the event of illness, depends.

The textbook complies with the Federal State Educational Standard for Secondary (Complete) general education, recommended by the Ministry of Education and Science of the Russian Federation and included in the Federal List of Textbooks.

The textbook is addressed to 11th grade students and is designed to teach the subject 1 or 2 hours a week.

Modern design, multi-level questions and tasks, additional information and the possibility of parallel work with an electronic application contribute to the effective assimilation of educational material.

Rice. 33. Winter coloring of a hare

So, as a result of the action driving forces evolution, organisms develop and improve adaptations to conditions environment. The consolidation of various adaptations in isolated populations can ultimately lead to the formation of new species.

Review questions and assignments

1. Give examples of the adaptation of organisms to living conditions.

2. Why do some animals have bright, unmasking colors, while others, on the contrary, have protective colors?

3. What is the essence of mimicry?

4. Does natural selection apply to animal behavior? Give examples.

5. What are the biological mechanisms for the emergence of adaptive (hiding and warning) coloration in animals?

6. Are physiological adaptations factors that determine the level of fitness of the organism as a whole?

7. What is the essence of the relativity of any adaptation to living conditions? Give examples.

Think! Do it!

1. Why is there no absolute adaptation to living conditions? Give examples to prove relative character any device.

2. Boar cubs have a characteristic striped coloring, which disappears with age. Give similar examples of color changes in adults compared to offspring. Can this pattern be considered common to the entire animal world? If not, then for which animals and why is it characteristic?

3. Gather information about animals with warning colors that live in your area. Explain why knowledge of this material is important for everyone. Make an information stand about these animals. Give a presentation on this topic to primary school students.

Working with a computer

Refer to the electronic application. Study the material and complete the assignments.

Repeat and remember!

Human

Behavioral adaptations are innate, unconditional reflex behavior. Innate abilities exist in all animals, including humans. A newborn baby can suck, swallow and digest food, blink and sneeze, react to light, sound and pain. These are examples unconditioned reflexes. Such forms of behavior arose in the process of evolution as a result of adaptation to certain, relatively constant environmental conditions. Unconditioned reflexes are inherited, so all animals are born with a ready-made complex of such reflexes.

Each unconditioned reflex occurs in response to a strictly defined stimulus (reinforcement): some - to food, others - to pain, others - to the appearance of new information etc. The reflex arcs of unconditioned reflexes are constant and pass through the spinal cord or brain stem.

One of the most complete classifications of unconditioned reflexes is the classification proposed by Academician P. V. Simonov. The scientist suggested dividing everything unconditioned reflexes into three groups, differing in the characteristics of the interaction of individuals with each other and with the environment. Vital reflexes(from Latin vita - life) are aimed at preserving the life of the individual. Failure to comply with them leads to the death of the individual, and implementation does not require the participation of another individual of the same species. This group includes food and drinking reflexes, homeostatic reflexes (maintaining a constant body temperature, optimal frequency breathing, heartbeat, etc.), defensive, which, in turn, are divided into passive-defensive (running away, hiding) and active-defensive (attacking a threatening object) and some others.

TO zoosocial, or role-playing reflexes include those variants of innate behavior that arise during interaction with other individuals of their own species. These are sexual, child-parent, territorial, hierarchical reflexes.

The third group is self-development reflexes. They are not related to adaptation to a specific situation, but seem to be directed to the future. These include exploratory, imitative and playful behavior.

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The grandiose inventions of the human mind never cease to amaze, there are no limits to imagination. But what nature has created for many centuries surpasses the most creative ideas and plans. 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, and adaptability to life. Examples of adaptation of organisms 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 the process of gradual degeneration of the physiological, morphological or psychological functions of a creature under conditions of a changed habitat. Both individuals and entire populations are subject to change.

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

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

A recent example of adaptation is a change in the habitat of a colony of green Mexican aratinga parrots. Recently, they changed their usual habitat and settled in the very mouth of the Masaya volcano, in an environment constantly saturated with highly concentrated sulfur gas. Scientists have not yet provided an explanation for this phenomenon.

Types of adaptation

A change in the entire form of existence of an organism is a functional adaptation. An example of adaptation, when a change in conditions leads 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’s adaptation to natural conditions or society). There are cases when a subject adapts the environment to suit his needs - this is objective adaptation.

Biologists divide types of adaptation according to three criteria:

• Morphological.
• Physiological.
• Behavioral or psychological.

Examples of animal or plant adaptations to 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 occurred during the process of evolution.

Below are morphological adaptations, examples from animal and flora, which we consider as a matter of course:

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

Physiological adaptations: examples

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

• The release of a strong odor by flowers to attract insects contributes to dust.
• The state of suspended animation that simple organisms are capable of entering allows them to maintain vital activity after many years. The oldest bacteria capable of reproducing is 250 years old.
• Accumulation of subcutaneous fat, which is converted into water, in camels.

Behavioral (psychological) adaptations

Examples of human adaptation are more related to the psychological factor. Behavioral characteristics are common to flora and fauna. Thus, in the process of evolution, change temperature regime causes some animals to hibernate, birds to fly south to return in the spring, trees to shed their leaves and slow down the movement of sap. The instinct to choose the most suitable partner for procreation drives the behavior of animals in mating season. Some northern frogs and turtles freeze completely during the winter and thaw and come to life when the weather gets warmer.

Factors driving the need for change

Any adaptation process is a response to environmental factors that lead to environmental change. 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 environment inanimate nature when climate, soil composition, water availability, cycles change solar activity. Physiological adaptations, examples of the influence of abiotic factors are equatorial fish that can breathe both in water and on land. They have adapted well to conditions where drying up of rivers is a common occurrence.

Anthropogenic factors - influence human activity that changes the environment.

Adaptations to the environment

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

Contrasting examples of adaptation to abnormal temperatures are described below.

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

The simplest microorganisms have been found in hydrothermal vents, where the water temperature exceeds boiling degrees.

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 to adapt to aquatic and non-aquatic environments.

Human adaptation

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

The flexibility of human behavior manifests itself every day. If you give the task: “give examples of people’s adaptation,” most begin to remember exceptional cases survival in These are rare cases, but in new circumstances it is characteristic 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 acceptance of 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 coping mechanisms

There are three types of human adaptation:

• Physiological. The most simple examples- acclimatization and adaptability to changes in time zones or daily work patterns. In the process of evolution, they formed various types people, depending on their territorial place of residence. Arctic, alpine, continental, desert, equatorial types differ significantly in physiological indicators.
• Psychological adaptation. This is a person’s ability to find moments of understanding with people of different psychotypes, in a country with a different level of mentality. Homo sapiens tend to change their established stereotypes under the influence of new information, special occasions, 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 in a person the need for social and psychological adaptation. Under their influence, mechanisms of physiological changes come into play, which also adapt to new conditions.

This mobilization of all body reactions is called adaptation syndrome. New reactions of the body appear in response to sudden changes in the environment. At the first stage - anxiety - there is a change physiological functions, changes in the functioning of metabolism and systems. Next, protective functions and organs (including the brain) are activated and begin to turn on their protective functions and hidden capabilities. The third stage of adaptation depends on individual characteristics: person or included in new life and returns to normal (in medicine, recovery occurs during this period), or the body does not accept stress, and the consequences take on a negative form.

Phenomena of the human body

Nature has a huge reserve of strength in man, 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 lies within us. Example of adaptation: the ability of people to adapt to normal life after 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 due to an incorrect lifestyle. Unfortunately, passion bad habits- This is also the difference between humans and other living organisms.

Adaptation– this is the adaptation of the organism to environmental conditions due to a complex of morphological, physiological, and behavioral characteristics.

Different organisms adapt to different environmental conditions, and as a result, moisture-loving hydrophytes and "dry-bearers" - xerophytes(Fig. 6); plants of saline soils – halophytes; shade tolerant plants ( sciophytes), and requiring full sunlight for normal development ( heliophytes); animals that live in deserts, steppes, forests or swamps are nocturnal or diurnal. Groups of species with a similar relationship to environmental conditions (that is, living in the same ecotopes) are called environmental groups.

The ability of plants and animals to adapt to unfavorable conditions differs. Due to the fact that animals are mobile, their adaptations are more diverse than those of plants. Animals can:

- avoid unfavorable conditions(birds from winter lack of food and cold fly to warm regions, deer and other ungulates roam in search of food, etc.);

– fall into suspended animation – a temporary state in which life processes are so slow that their visible manifestations are almost completely absent (insect torpor, vertebrate hibernation, etc.);

– adapt to life in unfavorable conditions (they are saved from frost by their fur and subcutaneous fat, desert animals have adaptations for economical use of water and cooling, etc.). (Fig. 7).

Plants are inactive and lead an attached lifestyle. Therefore, only the last two adaptation options are possible for them. Thus, plants are characterized by a decrease in the intensity of vital processes during unfavorable periods: they shed their leaves, overwinter in the form of dormant organs buried in the soil - bulbs, rhizomes, tubers, and remain in the state of seeds and spores in the soil. In bryophytes, the entire plant has the ability to undergo anabiosis, which can survive for several years in a dry state.

Plant resistance to unfavorable factors increases due to special physiological mechanisms: changes in osmotic pressure in cells, regulation of the intensity of evaporation using stomata, the use of “filter” membranes for selective absorption of substances, etc.

Adaptations different organisms are produced with at different speeds. They arise most quickly in insects, which in 10–20 generations can adapt to the action of a new insecticide, which explains the failure of chemical control of the density of insect pest populations. The process of developing adaptations in plants or birds occurs slowly, over centuries.

Observed changes in the behavior of organisms are usually associated with hidden characteristics that they had, as it were, “in reserve,” but under the influence of new factors they emerged and increased the stability of the species. Such hidden characteristics explain the resistance of some tree species to industrial pollution (poplar, larch, willow) and some weed species to herbicides.

The same ecological group often includes organisms that are not similar to each other. This is due to the fact that to the same environmental factor different types organisms can adapt in different ways.

For example, they experience the cold differently warm-blooded(they are called endothermic, from the Greek words endon - inside and terme - heat) and cold-blooded (ectothermic, from the Greek ektos - outside) organisms. (Fig. 8.)

The body temperature of endothermic organisms does not depend on the ambient temperature and is always more or less constant, its fluctuations do not exceed 2–4 o even in the most severe frosts and extreme heat. These animals (birds and mammals) maintain body temperature by internal heat generation based on intensive metabolism. They retain their body heat through warm “coats” made of feathers, wool, etc.

Physiological and morphological adaptations are complemented adaptive behavior(choosing places to sleep protected from the wind, building burrows and nests, group overnight stays with rodents, close groups of penguins keeping each other warm, etc.). If the ambient temperature is very high, then endothermic organisms are cooled due to special devices, for example, by evaporation of moisture from the surface of the mucous membranes of the oral cavity and upper respiratory tract. (For this reason, in hot weather, the dog’s breathing quickens and he sticks out his tongue.)

The body temperature and mobility of ectothermic animals depends on the ambient temperature. Insects and lizards at cool weather become lethargic and inactive. Many species of animals have the ability to choose a place from favorable conditions temperature, humidity and lighting sunlight(lizards bask on illuminated rock slabs).

However, absolute ectothermism is observed only in very small organisms. Most cold-blooded organisms are still capable of weak regulation of body temperature. For example, in actively flying insects - butterflies, bumblebees, body temperature is maintained at 36–40 o C even at air temperatures below 10 o C.

Similarly, species of one ecological group in plants differ in their appearance. They can also adapt to the same environmental conditions in different ways. Thus, different types of xerophytes save water in different ways: some have thick cell membranes, others have pubescence or a waxy coating on the leaves. Some xerophytes (for example, from the family Lamiaceae) produce pairs essential oils, which envelop them like a “blanket”, which reduces evaporation. The root system of some xerophytes is powerful, goes into the soil to a depth of several meters and reaches the level groundwater(camel thorn), in others it is superficial, but highly branched, which allows it to collect water from precipitation.

Among the xerophytes there are shrubs with very small hard leaves that can be shed in the driest time of the year (caragana shrub in the steppe, desert shrubs), turf grasses with narrow leaves (feather grass, fescue), succulents(from the Latin succulentus - succulent). Succulents have succulent leaves or stems that store water and are easily tolerated. high temperatures air. Succulents include American cacti and saxaul, which grows in Central Asian deserts. They have a special type of photosynthesis: the stomata open briefly and only at night; during these cool hours, plants store carbon dioxide, and during the day they use it for photosynthesis with closed stomata. (Fig. 9.)

A variety of adaptations to surviving unfavorable conditions on saline soils is also observed in halophytes. Among them there are plants that are able to accumulate salts in their bodies (saltweed, swede, sarsazan), secrete excess salts onto the surface of the leaves with special glands (kermek, tamarix), and “prevent” salts from entering their tissues due to a “root barrier” impenetrable to salts "(wormwood). In the latter case, the plants have to be content with a small amount of water and they have the appearance of xerophytes.

For this reason, one should not be surprised that in the same conditions there are plants and animals that are dissimilar to each other, which have adapted to these conditions in different ways.

Security questions

1. What is adaptation?

2. How can animals and plants adapt to unfavorable environmental conditions?

2. Give examples environmental groups plants and animals.

3. Tell us about the different adaptations of organisms to surviving the same unfavorable environmental conditions.

4. What is the difference between devices low temperatures in endothermic and ectothermic animals?