Morphological adaptations - adaptations of animals to environmental factors. Morphological adaptations of animals Examples of morphological adaptation

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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 assignments, additional information and the ability to work in parallel 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 of the driving forces of 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 the action apply? natural selection on 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.

Work with computer

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

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 conditions environment. 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 proposed dividing all 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 constant temperature body, optimal breathing rate, heartbeat, etc.), defensive, which, in turn, are divided into passive-defensive (running away, hiding) and active-defensive (attack on 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.

To survive in unfavorable conditions climatic conditions plants, animals and birds have some characteristics. These features are called "physiological adaptations", examples of which can be seen in almost every species of mammal, including humans.

Why is physiological adaptation necessary?

Living conditions in some parts of the planet are not entirely comfortable, nevertheless, there are various representatives of wildlife there. There are several reasons why these animals did not leave the unfavorable environment.

First of all, climatic conditions may have changed when a certain species already existed in a given area. Some animals are not adapted to migration. It is also possible that territorial features do not allow migration (islands, mountain plateaus, etc.). For certain type the changed living conditions still remain more suitable than in any other place. And physiological adaptation is the best option solving the problem.

What do you mean by adaptation?

Physiological adaptation is the harmony of organisms with a specific habitat. For example, the comfortable stay of its inhabitants in the desert is due to their adaptation to high temperatures and lack of access to water. Adaptation is the appearance of certain characteristics in organisms that allow them to get along with some elements of the environment. They arise during the process of certain mutations in the body. Physiological adaptations, examples of which are well known in the world, are, for example, the ability to echolocation in some animals (bats, dolphins, owls). This ability helps them navigate in a space with limited lighting (in the dark, in water).

Physiological adaptation is a set of reactions of the body to certain pathogenic factors in the environment. It provides organisms with a greater likelihood of survival and is one of the methods of natural selection for strong and resilient organisms in a population.

Types of physiological adaptation

Adaptation of the organism is distinguished between genotypic and phenotypic. Genotypic is based on the conditions of natural selection and mutations that led to changes in organisms of an entire species or population. It was in the process of this type of adaptation that the modern views animals, birds and humans. The genotypic form of adaptation is hereditary.

The phenotypic form of adaptation is due to individual changes in a particular organism for a comfortable stay in certain climatic conditions. It can also develop due to constant exposure to an aggressive environment. As a result, the body acquires resistance to its conditions.

Complex and cross adaptations

Complex adaptations occur in certain climatic conditions. For example, the body's adaptation to low temperatures during a long stay in the northern regions. This form of adaptation develops in every person when moving to a different climate zone. Depending on the characteristics of a particular organism and its health, this form of adaptation proceeds in different ways.

Cross adaptation is a form of habituation of the organism in which the development of resistance to one factor increases resistance to all factors of this group. A person's physiological adaptation to stress increases his resistance to some other factors, for example, to cold.

Based on positive cross-adaptations, a set of measures has been developed to strengthen the heart muscle and prevent heart attacks. Under natural conditions, those people who have more often encountered stressful situations in their lives are less susceptible to the consequences of myocardial infarction than those who led a calm lifestyle.

Types of adaptive reactions

There are two types of adaptive reactions of the body. The first type is called “passive adaptations”. These reactions take place at the cellular level. They characterize the formation of the degree of resistance of the organism to the effects of negative factor environment. For example, change atmospheric pressure. Passive adaptation allows you to maintain the normal functionality of the body with small fluctuations in atmospheric pressure.

The most well-known physiological adaptations in animals of the passive type are the protective reactions of a living organism to the effects of cold. Hibernation, during which life processes slow down, is characteristic of some species of plants and animals.

The second type of adaptive reactions is called active and involves the body’s protective measures when exposed to pathogenic factors. In this case, the internal environment of the body remains constant. This type of adaptation is inherent highly developed mammals and to man.

Examples of physiological adaptations

Physiological adaptation of a person is manifested in all situations that are non-standard for his environment and lifestyle. Acclimatization is the most famous example adaptations. For different organisms this process occurs at different speeds. Some people need a few days to get used to new conditions, for many it will take months. Also, the speed of adaptation depends on the degree of difference from the usual habitat.

In hostile environments, many mammals and birds have a characteristic set of body responses that make up their physiological adaptations. Examples (in animals) can be observed in almost every climate zone. For example, desert dwellers accumulate reserves of subcutaneous fat, which oxidizes and forms water. This process is observed before the onset of a period of drought.

Physiological adaptation in plants also takes place. But it is passive in nature. An example of such an adaptation is trees shedding leaves when the cold season approaches. The bud areas are covered with scales, which protect them from the harmful effects of low temperatures and snow and wind. Metabolic processes in plants slow down.

In combination with morphological adaptation, the physiological reactions of the body provide it with high level survival in unfavorable conditions and sudden changes in the environment.

Living organisms are adapted to the environmental conditions in which their ancestors lived for a long time. Adaptations to environmental conditions are also called adaptations. They arise during the evolution of the population, forming a new subspecies, species, genus, etc. Different genotypes accumulate in the population, manifesting themselves in different phenotypes. Those phenotypes that best suit environmental conditions are more likely to survive and leave offspring. Thus, the entire population is “saturated” with adaptations useful for a given habitat.

Adaptations vary in their forms (types). They can affect body structure, behavior, appearance, cell biochemistry, etc. There are following forms adaptations.

Adaptations of body structure (morphological adaptations). They can be significant (at the level of orders, classes, etc.) or small (at the level of species). Examples of the former are the appearance of hair in mammals, the ability to fly in birds, and lungs in amphibians. An example of small adaptations is the different beak structure of closely related bird species that feed in different ways.

Physiological adaptations. This is a restructuring of metabolism. Each species, adapted to its own living conditions, has its own metabolic characteristics. So, some species eat a lot (for example, birds), because their metabolism is quite fast (birds require a lot of energy to fly). Some species may not drink for a long time (camels). Marine animals can drink sea water, while freshwater and terrestrial animals cannot.

Biochemical adaptations. This special structure proteins, fats, which give organisms the opportunity to live in certain conditions. For example, at low temperatures. Or the ability of organisms to produce poisons, toxins, odorous substances for protection.

Protective coloration. Many animals, in the process of evolution, acquire a body color that makes them less noticeable against the background of grass, trees, soil, i.e., where they live. This allows some to protect themselves from predators, while others can sneak up unnoticed and attack. Baby mammals and chicks often have a protective coloration. While adult individuals may no longer have a protective coloration.

Warning (threatening) coloring. This coloring is bright and memorable. Characteristic of stinging and poisonous insects. For example, birds don't eat wasps. Having tried it once, they remember the characteristic color of the wasp for the rest of their lives.

Mimicry- external resemblance to poisonous or stinging species, dangerous animals. Allows you to avoid being eaten by predators who “seem” to be in front of them dangerous look. So hover flies look like bees, some non-venomous snakes Poisonous butterflies may have patterns on their wings that resemble the eyes of predators.

Disguise- the similarity of the body shape of the organism with the object inanimate nature. Not only does it arise here protective coloration, but the organism itself in its shape resembles an object of inanimate nature. For example, a branch, a leaf. Camouflage is mainly characteristic of insects.

Behavioral adaptations. Each animal species develops a special type of behavior that allows it to best adapt to specific living conditions. This includes storing food, caring for offspring, mating behavior, hibernation, hiding before an attack, migration, etc.

Often different adaptations are interconnected. For example, protective coloring can be combined with the animal freezing (with behavioral adaptation) at the moment of danger. Also, many morphological adaptations are due to physiological ones.

Morphological adaptations involve changes in the shape or structure of an organism. An example of such an adaptation is a hard shell, which provides protection from predatory animals. Physiological adaptations are associated with chemical processes in the body. Thus, the smell of a flower can serve to attract insects and thereby contribute to pollination of the plant. Behavioral adaptation associated with a certain aspect of the animal’s life. A typical example is winter dream at the bear. Most adaptations are a combination of these types. For example, blood sucking in mosquitoes is ensured complex combination such adaptations as the development of specialized parts of the oral apparatus adapted for sucking, the formation of search behavior for finding a prey animal, as well as the development salivary glands special secretions that prevent the clotting of sucked blood.

All plants and animals constantly adapt to their environment. To understand how this happens, it is necessary to consider not only the animal or plant as a whole, but also the genetic basis of adaptation.

Genetic basis.

In each species, the program for the development of traits is embedded in the genetic material. The material and the program encoded in it are passed on from one generation to the next, remaining relatively unchanged, so that representatives of a given species look and behave almost the same. However, in a population of organisms of any species there are always small changes in the genetic material and, therefore, variations in the characteristics of individual individuals. It is from these diverse genetic variations that the process of adaptation selects those traits or favors the development of those traits that most increase the chances of survival and thereby the preservation of genetic material. Adaptation can thus be thought of as the process by which genetic material increases its chances of persistence in subsequent generations. From this point of view, each species represents a successful way of preserving certain genetic material.

To pass on genetic material, an individual of any species must be able to feed, survive until the breeding season, leave offspring, and then spread them over as wide an area as possible.

Nutrition.

All plants and animals must receive energy and various substances from the environment, primarily oxygen, water and inorganic compounds. Almost all plants use the energy of the Sun, transforming it through the process of photosynthesis. Animals get energy by eating plants or other animals.

Each species is adapted in a certain way to provide itself with food. Hawks have sharp talons for capturing prey, and the location of the eyes in the front of the head allows them to judge the depth of space, which is necessary for hunting while flying at high speed. Other birds, such as herons, have developed long neck and legs. They obtain food by carefully wandering through shallow water and lying in wait for unwary aquatic animals. Darwin's finches are a group of closely related bird species with Galapagos Islands– represent a classic example of highly specialized adaptation to in different ways nutrition. Thanks to one or another adaptive morphological changes, primarily in the structure of the beak, some species became granivorous, others became insectivorous.

Turning to fish, predators such as sharks and barracudas have sharp teeth to catch prey. Others, such as small anchovies and herring, obtain small food particles by filtering sea ​​water through comb-shaped gill rakers.

In mammals, an excellent example of adaptation to the type of nutrition is the structural features of teeth. The canines and molars of leopards and other felines are exceptionally sharp, which allows these animals to hold and tear the body of their prey. Deer, horses, antelopes and other grazing animals have large molars with wide, ribbed surfaces adapted for chewing grass and other plant foods.

Various ways to receive nutrients can be observed not only in animals, but also in plants. Many of them, primarily legumes - peas, clover and others - have developed symbiotic, i.e. mutually beneficial relationship with bacteria: bacteria convert atmospheric nitrogen into a chemical form available to plants, and plants provide energy to bacteria. Carnivorous plants such as sarracenia and sundew obtain nitrogen from the bodies of insects captured by trapping leaves.

Protection.

The environment consists of living and nonliving components. The living environment of any species includes animals that feed on members of that species. Adaptations of predatory species are aimed at efficient food acquisition; Prey species adapt to avoid becoming prey to predators.

Many potential prey species have protective or camouflage colors that hide them from predators. So, in some species of deer spotted skin young individuals are invisible against the background of alternating spots of light and shadow, and white hares are difficult to distinguish against the background of snow cover. Long thin bodies Stick insects are also difficult to see because they resemble twigs or twigs from bushes and trees.

Deer, hares, kangaroos and many other animals have developed long legs allowing them to escape from predators. Some animals, such as opossums and hog snakes, have even developed a unique behavior called death faking, which increases their chances of survival, since many predators do not eat carrion.

Some types of plants are covered with thorns or thorns that repel animals. Many plants have a disgusting taste to animals.

Environmental factors, in particular climate, often place living organisms in difficult conditions. For example, animals and plants often have to adapt to temperature extremes. Animals escape the cold by using insulating fur or feathers, migrating to areas with more warm climate or falling into hibernation. Most plants survive the cold by entering a state of dormancy, equivalent to hibernation in animals.

In hot weather, the animal cools itself by sweating or frequent breathing, which increases evaporation. Some animals, especially reptiles and amphibians, are able to enter summer hibernation, which is essentially similar to winter hibernation, but is caused by heat rather than cold. Others are simply looking for a cool place.

Plants can maintain their temperature to some extent by regulating the rate of evaporation, which has the same cooling effect as sweating in animals.

Reproduction.

A critical step in ensuring the continuity of life is reproduction, the process by which genetic material is passed on to the next generation. Reproduction has two important aspects: the meeting of opposite-sex individuals to exchange genetic material and the raising of offspring.

Among the adaptations that ensure the meeting of individuals of different sexes is sound communication. In some species, the sense of smell plays an important role in this sense. For example, cats are strongly attracted to the smell of a cat in heat. Many insects secrete the so-called. attractants – chemical substances, attracting individuals of the opposite sex. Flower scents are an effective plant adaptation to attract pollinating insects. Some flowers smell sweet and attract nectar-feeding bees; others smell disgusting, attracting flies that feed on carrion.

Vision is also very important for meeting individuals of different sexes. In birds, the mating behavior of the male, his lush feathers and bright color attract a female and prepare her for copulation. Flower color in plants often indicates which animal is needed to pollinate that plant. For example, flowers pollinated by hummingbirds are colored red, which attracts these birds.

Many animals have developed ways to protect their offspring in the early stages of life. Most adaptations of this kind are behavioral and involve actions by one or both parents that increase the chances of survival of the young. Most birds build nests that are specific to each species. However, some species, such as the cowbird, lay eggs in the nests of other bird species and entrust the young to the parental care of the host species. In many birds and mammals, as well as some fish, there is a period when one of the parents takes great risks, taking on the function of protecting the offspring. Although this behavior sometimes threatens the death of the parent, it ensures the safety of the offspring and the preservation of genetic material.

A number of animal and plant species use a different reproductive strategy: they produce a huge number of offspring and leave them unprotected. In this case, the low chances of survival of an individual growing individual are balanced by the large number of offspring.

Settlement.

Most species have developed mechanisms to remove offspring from the places where they were born. This process, called dispersal, increases the likelihood that offspring will grow up in unoccupied territory.

Most animals simply avoid places where there is too much competition. However, evidence is accumulating that dispersal is driven by genetic mechanisms.

Many plants have adapted to dispersing seeds with the help of animals. Thus, the fruits of the cocklebur have hooks on the surface, with which they cling to the fur of passing animals. Other plants produce tasty, fleshy fruits, such as berries, that are eaten by animals; the seeds pass through the digestive tract and are “sown” intact elsewhere. Plants also use wind to spread. For example, the wind carries the “propellers” of maple seeds, as well as cottonweed seeds, which have tufts of fine hairs. Steppe plants such as tumbleweeds, which acquire a spherical shape by the time the seeds ripen, are driven by the wind over long distances, dispersing seeds along the way.

Above are just some of the most vivid examples adaptations. However, almost every trait of any species is the result of adaptation. All these signs form a harmonious combination, which allows the body to successfully lead its own special way of life. Man in all his features, from brain structure to shape thumb on the leg, is the result of adaptation. Adaptive traits contributed to the survival and reproduction of his ancestors, who had the same traits. In general, the concept of adaptation has great importance for all areas of biology.

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

This pattern, known as Allen's 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, and the northern wild boar and the wild boar in the Caucasus. Mongrel domestic dogs in Krasnodar region, large cattle local selection are distinguished by lower live weight compared to representatives of these species, say, Arkhangelsk.

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

And animals of the tropics have simply huge ears (elephants, rabbits, ungulates). Ears are indicative African elephant, the area of ​​which is 1/6 of the surface of the animal’s entire body. They have abundant innervation and vascularization. In hot weather, approximately 1/3 of all circulating blood passes through the circulatory system of the ears of an elephant. As a result of increased blood flow in external environment excess heat is released.

The desert hare Lapus alleni is even more impressive for its adaptation to high temperatures. In this rodent, 25% of the total body surface is covered by bare ears. It is unclear 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 second tasks are solved by the animal very effectively. The rodent has a keen ear. Developed circulatory system ears with a unique vasomotor ability serves only thermoregulation. By increasing and limiting blood flow through the ears, 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, the surface of the auricles is released into the external environment. a large number of excess thermal energy in both the elephant and especially the lepus.

Fits well into the context of the problem being discussed and the body structure of the relative modern elephants- mammoth. This northern equivalent of the elephant, judging by the preserved remains discovered in the tundra, was significantly larger than its southern relative. But the mammoth's ears had a smaller relative area and were also covered with thick hair. The mammoth had relatively short limbs and a short trunk.

Long limbs are disadvantageous in low temperature conditions, 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, long-legged.

According to N. 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 low point melting and does not freeze even in severe frosts. However, bone fat from bones that are not in contact with a cold surface, such as the femur, has the usual physicochemical properties. Liquid fat in the bones of the lower limbs provides insulation and joint mobility.

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

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

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

The internal fat of animals in hot and arid climates 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.

Camels, fat-tailed and fat-tailed sheep, and zebu cattle serve as examples of unpretentiousness in arid desert conditions. 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 has even more - about 100 liters. The latest examples illustrate the morphophysiological and biochemical adaptations of animals to extreme temperatures. Morphological adaptations extend to many organs. Northern animals have a large volume of the gastrointestinal tract and a large relative length of the intestines; they deposit more internal fat in the omentum and perinephric capsule.

Animals of the arid zone have a number of morphofunctional features of the urinary formation and excretion system. Back at the beginning of the 20th century. morphologists have discovered differences in the structure of the kidneys of desert animals and animals temperate climate. In animals in hot climates, the medulla is more developed due to the enlargement of the rectal tubular part of the nephron.

For example, at African lion The thickness of the renal medulla is 34 mm, while in the 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 urinary system. Thus, for a kangaroo rat, a pronounced ability is normal Bladder reabsorb water from secondary urine. 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. Thus, in the urine of a kangaroo rat the concentration of this hormone is 50 units/ml, in a laboratory rat it is only 5-7 units/ml. In the pituitary tissue of a kangaroo rat, the content of vasopressin is 0.9 units/mg, in a laboratory rat it is three times less (0.3 units/mg). With water deprivation, differences between animals remain, although the secretory activity of the neurohypophysis increases in both one and the other animal.

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

The temperature of the environment 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 is down. All this helps to reduce the thermal conductivity of the body surface. In animals of hot climates the opposite is true: thin skin, sparse wool, low thermal insulation properties of the skin in general.

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