9 cl subspecies of animals presentation. Adaptive features of the structure of body color and behavior of animals, as a result of the action of natural selection. K.O.Z. How do such perfect adaptations come about?

Biology lesson summary for grade 9

Topic: "Adaptive features of the structure, body color and behavior of animals"

Textbook: "Biology general laws of grade 9" S.G. Mamontov, V.B. Zakharov, N.I. Sonin

biology teacher MBOU secondary school № 37 Lukyanenko A.S.

Target: to get acquainted with different types of adaptability of living organisms to their environment, to understand the relative nature of adaptability.

Tasks:

to continue the formation of schoolchildren's ecological culture, belief in the need to preserve the species diversity of plants and animals. to draw conclusions about the natural causes of the formation of adaptations, using the doctrine of the driving forces of evolution; broaden the horizons of students.

№ lesson

during the classes

1. Updating previous knowledge

K.O.Z.

What forces of evolution have we met?

What force of evolution Charles Darwin considered the main one?

What organisms survive and reproduce as a result of natural selection?

How do you think with what you can adapt to the environment?

K.O.Z.

Let's remember such a force of evolution as the struggle for existence. What forms of struggle for existence do you know? What is the peculiarity of the interspecies struggle for existence, between whom does it take place? how should predators and their prey adapt?

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SLIDE number 13-14warning coloration However, animals often show not hiding body coloration, but, on the contrary, attracting attention, unmasking. This form of fixture is called warning coloration. It is characteristic of most stinging, poisonous, disgusting-smelling or disgusting-tasting animals. Like stoplights, these patterns and color combinations should be easily recognized by animals. They mean: “Dangerous!”, “Don't come near!”, “It's better not to mess with me!”. The birds never peck the ladybug, which is very noticeable, because of the poisonous secretion secreted by the insect. Inedible caterpillars have a bright warning color, many Poisonous snakes... There are real dandies among amphibians. They are spectacularly colored, often sluggish, diurnal and do not even try to hide from predators, unlike their more numerous disguised relatives who go in search of food at night when they are less visible. The most peculiar among the amphibian dandies are perhaps the poison dart frogs, the inhabitants of the Central and South America... Their skin glands produce powerful paralyzing poisons, so that a predator that has tried to eat with such a frog and survived associates the experienced unpleasant moments with its bright colors and further diligently avoids its kind. Among the approximately one hundred thousand species that make up the order of lepidoptera, or butterflies, bears belong not only to the most familiar, but also to the most beautiful. She has an extremely effective warning color - orange-black and yellow-black with patterns of spots and stripes. The bear is very pretty, but poisonous. Special glands produce strong toxins that enter the butterfly's bloodstream. Other glands contain fluid with an unpleasant warning odor. In the tropical coastal waters of Australia, New Guinea, Indonesia and the Philippines, a small (up to 20 cm long with tentacles) blue-ringed octopus lives. The bright orange round spots are bordered by distinctive blue rings. Like all representatives of the genus, the blue-ringed octopus has an amazing ability to regenerate, and, having lost one or more of its eight tentacles in battle, can quickly grow new ones. As beautiful as this octopus is, it is also poisonous. The animal's saliva contains the strongest neurotoxin. The bite of a blue-ringed octopus is fatal. The poison almost instantly paralyzes the nervous system of any living creature, and there is no antidote for it.SLIDE NO.mimicry The effectiveness of the warning coloration was the cause of a very interesting phenomenon - imitation, or mimicry. Mimicry is the imitation of a less protected organism of one species over a more protected organism of another species. This imitation can manifest itself in body shape, color, etc. Covered with warning stripes, but completely harmless, the hoverfly extracts nectar from the flower, just like honey bees with a formidable sting. Hoverfly mimicry is not limited to coloration, but includes behavior. The hoverflies imitate the sounds made by bees and wasps and, if disturbed, make a menacing buzz. All this together guarantees immunity to the hoverfly. The beautiful Danaida butterfly owes its inedibility to the fact that its caterpillars feed on the leaves of poisonous lettuce, which is dangerous for livestock and other vertebrates. The winged predators quickly learned not to touch the Danaids, and at the same time their imitator, one of the nymphalids - only slightly tasteless. The glass butterfly is remarkably similar to a wasp. Its wings are completely transparent, since it has no scales covering the wings of butterflies. When flying, it buzzes like wasps, and flies just as swiftly and restlessly as they do. Already imitates the color of the viper, it is given out only by yellow spots on the head. Poisonous coral snakes have acquired many imitators. For example, the Arizona king snake, which is not venomous.SLIDE NO. disguise In animals leading a hidden, lurking way of life, devices that make them resemble objects are useful. environment- disguise. For example, moth caterpillars resemble knots in body shape and color. Stick insects look like a small brown or green twig, some butterflies resemble dry leaves, and spiders imitate thorns. Great masters of disguise owe much of their success to their ability to freeze at the moment when they are threatened with an attack or they themselves are preparing to grab prey. Among animals, those who imitate flowers in one way or another are especially diverse. For example, flower mantises are so similar to certain parts of the plant that, deceived by the similarity, other insects descend directly on them and fall into the arms of a predator.Students write down definitions and draw conclusions about the relative nature of any adaptation..

K.O.Z. How do such perfect adaptations come about? The clue lies in the intricate process of natural selection. For example, the distant ancestor of a butterfly, now almost indistinguishable from a dry leaf, was born with a random set of genes that gave it a slightly more similarity to a dry leaf. Therefore, it was somewhat more difficult for birds to find this butterfly among dry leaves, and as a result, she and similar individuals survived in greater numbers. Consequently, they left more offspring. And the sign of "dry leaf" became more and more distinct and widespread. Any signs result from mutations. One major mutation can occur, or a huge number of small ones, which happens much more often. Those of them that increase vitality are passed on to subsequent generations, become fixed and become adaptations. Each adaptation is developed on the basis of hereditary variability in the process of struggle for existence and selection over a number of generations.

What conclusions can be drawn from all of the above?

1. The general adaptability of organisms to environmental conditions consists of many individual adaptations of various scales.2. All adaptations arise in the course of evolution as a result of natural selection.3.Any fixture is relative.Thus, fitness is the relative expediency of the structure and functions of the body, which is the result of natural selection.

Reflection D.Z.

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The presentation on the topic "The fitness of organisms" can be downloaded absolutely free of charge on our website. Project subject: Biology. Colorful slides and illustrations will help you engage your classmates or audience. To view the content, use the player, or if you want to download the report, click on the corresponding text under the player. The presentation contains 33 slide (s).

Presentation slides

Slide 1

The adaptability of organisms to environmental conditions as a result of the action of natural selection

Compiled by S.V.Bolshakov

Slide 2

Plant and animal species are remarkably adapted to the environmental conditions in which they live. A huge number of the most diverse structural features are known, providing a high level of adaptation of the species to the environment. The concept of "fitness of the species" includes not only outward signs, but also the conformity of the structure internal organs the functions they perform, for example the long and complex digestive tract of animals that eat plant foods (ruminants). Correspondence of the physiological functions of the organism to the living conditions, their complexity and diversity are also included in the concept of fitness.

Slide 3

Adaptive features of the structure, body color and behavior of animals. In animals, the shape of the body is adaptive. The shape of the aquatic mammal, the dolphin, is well known. His movements are light and precise. Self-driving speed in water reaches 40 km / h. Cases are often described of dolphins accompanying fast sea vessels, for example, destroyers moving at a speed of 65 km / h.

http://www.botik.ru/~yz/rrp/puzlyary/prize/index.koi8.html

Slide 4

This is explained by the fact that dolphins are attached to the bow of the ship and use the hydrodynamic force of the ship's waves. But this is not their natural speed. The density of water is 800 times that of air. How does a dolphin manage to overcome it? In addition to other structural features, the shape of the body contributes to the ideal adaptation of the dolphin to the habitat and lifestyle. The torpedo shape of the body avoids the formation of a swirl of water flows around the dolphin.

http://desktop.kazansoft.ru/preview/cat1-117.html

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The streamlined body shape contributes to the rapid movement of animals in the air. Flight feathers and contour feathers covering the bird's body completely smooth out its shape. Birds are devoid of protruding auricles; in flight, they usually retract their legs. As a result, birds are much faster than all other animals in speed. For example, a peregrine falcon dives on its prey at a speed of up to 290 km / h.

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Birds move quickly even in water. A chinstrap penguin was observed swimming underwater at a speed of about 35 km / h.

Adelie Penguin

Slide 8

In animals leading a secretive, lurking way of life, adaptations that give them a resemblance to environmental objects are useful. The bizarre body shape of fish living in algae thickets helps them successfully hide from enemies.

http://forum.allgaz.ru/showthread.php?t=10009&page=4

Slide 9

The similarity with objects of the habitat is widespread in insects. Beetles are known for their appearance resembling lichens, cicadas, similar to the types of those shrubs among which they live. Stick insects look like a small brown or green twig, and orthoptera insects mimic a leaf.

Stick insects http://macroid.ru/showphoto.php?photo=11879

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Protective coloration also serves as a means of protection against enemies. Birds incubating eggs on the ground merge with the surrounding background. Their eggs, which have a pigmented shell, and the chicks hatching from them are also hardly noticeable. The protective nature of egg pigmentation is confirmed by the fact that in species whose eggs are inaccessible to enemies - large predators, or in birds laying eggs on rocks or burying them in the ground, the protective color of the shell does not develop.

http://kizhi.karelia.ru/gallery/life_moment/index_e.php?i=16

Slide 12

Protective coloration is widespread among a wide variety of animals. Caterpillars of butterflies are often green, the color of the leaves, or dark, the color of the bark or earth. Bottom fish are usually colored like a sandy bottom (rays and flounders). At the same time, flounders are still able to change color depending on the color of the surrounding background.

Polar flounder

Slide 13

The ability to change color by redistributing pigment in the integument of the body is also known in terrestrial animals (chameleon).

Chameleons http://ru.wikipedia.org/wiki/Chameleons

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Desert animals are usually yellow-brown or sandy-yellow in color.

Desert King Snake (Lampropeltis getula ... http://www.terrariy.ru/Anim/Snake/Desert_p.htm

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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, ptarmigan) are white in winter, which makes them invisible in the snow.

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However, animals often show not hiding body coloration, but, on the contrary, attracting attention, unmasking. This color is characteristic of poisonous, scalding or stinging insects: bees, wasps, blister beetles.

Honey bee

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The birds never peck the ladybug, which is very noticeable, because of the poisonous secretion secreted by the insect.

Photos of ladybirds photo 14 http://basik.ru/macro/1778/

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Inedible caterpillars and many poisonous snakes have a bright warning color. The bright color warns the predator in advance of the futility and danger of an attack. Through trial and error, predators quickly learn to avoid attacking prey with warning coloration.

Poisonous snake cobra. http://900igr.net/Detskie_prezentatsii/Biologija.Morskie_zhiteli/Zmei_1.files/detskie_kartinki_zhivotnykh_020_JAdovitaja_zmeja_kobra_vsta.html

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The protective effect of protective or warning coloration is enhanced when combined with appropriate behavior. For example, the bittern nests in the reeds. In moments of danger, she stretches her neck, lifts her head up and freezes. In this position, it is difficult to detect it even at close range.

Drink big

Slide 21

Many other animals that do not have active protective equipment, in case of danger, assume a resting pose and freeze (insects, fish, amphibians, birds). On the contrary, warning coloration in animals is combined with demonstrative behavior that frightens off a predator. The effectiveness of the warning coloration was the cause of a very interesting phenomenon - imitation, or mimicry. Mimicry refers to the resemblance of a defenseless or edible species to one or more unrelated species that are well protected and have a warning coloration. One of the cockroach species is very similar to the ladybug in size, body shape and distribution of age spots.

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Some edible butterflies mimic the body shape and color of poisonous butterflies, flies - wasps. The emergence of mimicry is associated with the accumulation, under the control of natural selection, of small successful mutations in edible species in the conditions of their cohabitation with inedible ones.

An example of mimicry: a fly of the hoverfly family ... http://www.enci.ru/

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It is clear that the imitation of some species by others is justified: a much smaller part of individuals of both the species that served as the model and the imitating species are subject to extermination. It is necessary, however, that the number of the imitator species was significantly less than the number of the model. Otherwise, mimicry is not useful: the predator will not develop a persistent conditioned reflex the shape or color to be avoided. How is the abundance of the mimic species kept low? It turned out that the gene pool of these species is saturated with lethal mutations. In a homozygous state, these mutations cause the death of insects, as a result of which a high percentage of individuals do not live to maturity.

A cuckoo egg in a clutch of a blue nightingale. http://kniiekotija.ucoz.ru/forum/58-145-3

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In addition to protective coloration, other means of protection are observed in animals and plants. Plants often have needles and thorns that protect them from being eaten by herbivores (cacti, rose hips, hawthorn, sea buckthorn, etc.).

http://www.tiensmed.ru/news/shipovnik-wkti/

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The same role is played by toxic substances that burn the hairs, for example, in nettles. Crystals of calcium oxalate accumulating in the thorns of some plants protect them from being eaten by caterpillars, snails and even rodents.

Stinging nettle

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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 needles of the hedgehog and the porcupine also serve the same purpose. All these adaptations could appear only as a result of natural selection, that is, the predominant survival of better protected individuals.

Turtle elephant

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Adaptive behavior is of great importance for the survival of organisms in the struggle for existence. In addition to hiding or demonstrative, frightening behavior when an enemy approaches, there are many other options for adaptive behavior that ensure the survival of adults or juveniles. This includes storing feed for an 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 kg in total.

Root vole - Microtus oeconomus (Pallas http://www.apus.ru/site.xp/049051056048124053054050052.html

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Burrowing rodents (mole rats, etc.) accumulate pieces of oak roots, acorns, potatoes, steppe peas - up to 14 kg.

Thread. skajazz. mole rats. http://fon-shcmal.livejournal.com/1840.html

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Great gerbil living in deserts Central Asia, at the beginning of summer, cuts the grass and drags it into burrows or leaves it on the surface in the form of stacks. This food is used in the second half of summer, in autumn and winter.

Large gerbils are typical desert dwellers. http://elementy.ru/news/430180

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The river beaver collects stumps of trees, branches, etc., which it puts into the water near its dwelling. These warehouses can reach a volume of 20 cubic meters.

Beavers are the most famous "builders" of dams in rivers and streams, and ... http://www.ff18.ru/bobry/bobry.html

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Question 1. Give examples of the adaptability of organisms to the conditions of existence based on their own observations.

In the course of evolution, organisms acquire various properties allowing them to more successfully adapt to habitat conditions. For example, the fur of animals of the north (polar foxes, bears) is white, making them almost invisible against the background of snow. Insects that feed on flower nectar have the structure and length of the proboscis, ideal for this. Seal fins, transformed from the paws of their land ancestors, are perfectly adapted to locomotion in the water. Giraffes live in the savannah and eat the leaves of trees on high altitude, in which a long neck helps them.

There are many such examples, since each living creature has a large number of characteristics acquired in the process of adapting to specific living conditions.

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

Two types of coloring correspond to two variants of behavior strategy. With one of them, the animal seeks to remain unnoticed, trying to avoid meeting a predator or sneaking up on the prey. For this, a patronizing color is used, which allows it to blend in with the background. On the other hand, animals that are dangerous or poisonous often emphasize this in every possible way. They use bright, unmasking colors, warning: "don't eat me." In addition to poisonous organisms, this strategy is used by harmless species mimicking them. Organisms can have unmasking coloration for a completely different reason - in connection with the desire to attract a partner for reproduction (bright coloration of many male birds, fish, reptiles, butterflies, etc.). In this case, the task of procreation comes into conflict with the instinct of self-preservation, but it turns out to be more significant for the organism.

Question 3. What is the essence of mimicry? Compare mimicry and disguise. What are their fundamental differences? How are they similar?

The essence of mimicry (from the Greek. Mimikos - imitative) is that harmless animals in the process of evolution acquire similarities with dangerous (poisonous) species. This allows them to avoid being attacked by predators. Some non-venomous snakes are an example: there is a species of snake that is similar in color to the deadly asp and differs from it only in the alternation of stripes. In addition to coloring, mimic animals possess characteristic behavior: hover flies behave like wasps, mimicking aggression.

Question 4. Does the action of natural selection extend to the behavior of animals? Give examples.

Natural selection influences not only the external signs of the organism, but also the behavior. This applies primarily to innate (instinctive) forms of behavior. Such forms are very diverse: methods of obtaining food, manifestations of fear and aggression, sexual behavior, parental behavior, etc. A spider weaves a net, a bee builds honeycombs, a cat at the moment of danger takes a threatening pose, chipmunks make supplies and hibernate for the winter and etc. Mating rituals are very complex, strict adherence to which is one of the ways for animals to prevent interspecies crossing.

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

The biological mechanism that ensures the emergence of adaptive coloration is natural selection. In the process of evolution in a population that, due to the diversity of the gene pool, was distinguished by a very wide spectrum of colors, those individuals that were less noticeable against the background of the environment predominantly survived and left offspring. As a result, the proportion of the corresponding genotypes was constantly growing. Subsequently, this phenotype, and hence the genotype, was fixed in the population with the help of stabilizing selection. In the case of the warning coloration, similar processes occurred. For example, birds initially find and eat bright insects more easily. If these insects turn out to be poisonous, then the birds quickly learn not to touch them and prefer more modestly colored prey. Thus, individuals with a bright color, which is easy to identify as poisonous, are preserved and leave offspring. Over time, this trait is fixed in the population.

Question 6. Are there living organisms that do not have adaptive structural features? Justify the answer.

Adaptation is a set of features of the structure, physiology and behavior of living organisms to specific conditions in which they can normally exist and leave offspring.

The emergence of adaptation to the environment is the main result of evolution. Therefore, evolution can be viewed as a process of the emergence of adaptations or adaptations.

Organisms that failed to adapt to the world around them died out.

Plants and animals are adapted to the environmental conditions in which they live. The concept of "fitness of the species" includes not only external signs, but also the correspondence of the structure of internal organs to the functions they perform ( for example, the long and complex digestive tract of ruminants that feed on plant foods). Correspondence of the physiological functions of the organism to the conditions of their habitation, their complexity and diversity are also included in the concept of fitness.

There is no doubt about the consistency of the activity of individual parts and systems within the organism itself. For a long time, such an expediency of the structure served as an argument in favor of the divine origin of living nature. But Darwin's theory of evolution was able to explain this from a materialistic standpoint. At present, the evolutionary approach to the consideration of biological laws serves as a natural scientific basis for explaining the expediency of the structure of living organisms and their adaptability to habitat conditions.

Adaptive features of the structure, body color and behavior of animals

Streamlined body shape- adaptation to overcoming the resistance of air (for birds) and water (for aquatic animals) when moving in these environments. This shape allows you to develop a high speed of movement and save energy at the same time.

Protective coloration and body shape- the color and shape of the animal's body, contributing to the preservation of its life in the struggle for existence. Protective coloration and body shape are very diverse and are found among many groups of invertebrates and vertebrates. There are 3 types of protective color and body shape: disguise , demonstration and mimicry .

Disguise- a device in which the shape of the body and color of the animal merge with the surrounding objects. For example, the caterpillars of some butterflies resemble twigs in body shape and color.

Animals living in the grass are green in color: lizards, grasshoppers, caterpillars, desert dwellers - yellow or brown: desert locust, eared roundhead, saiga.

Some animals change color during ontogenesis (cubs and adults of seals), in different seasons ( arctic fox, white hare, squirrel and many others).

Some animals are able to change color in accordance with the background, which is achieved by the redistribution of pigments in the chromatophores of the integument of the body ( cuttlefish, flounder, agamas and etc.). Camouflage coloring is usually combined with a resting pose.

Disguise contributes to success in the struggle for existence.

Dismembering coloration(disruptive coloration) - coloration with the presence of contrasting stripes or spots that break the body contour into separate areas, making the animal invisible against the surrounding background.

Dissecting coloration is often combined with mimicking surfaces and backgrounds and is found in many animals: giraffe, zebras, chipmunks, in some fish, amphibians, reptiles, from insects — in locusts, many butterflies and their caterpillars.

Creeping coloration is based on the counter-shadow effect: the most brightly illuminated parts of the body are colored darker than the less illuminated ones: the color seems more monotonous, and the outlines of the animal merge with the background. This color (dark back - light belly) is typical for most fish and other inhabitants of the water column, for many birds and some mammals ( deer, hares).

Warning coloring- a kind of patronizing color and form, in which inedible animals have a bright, catchy, sometimes motley, color. These animals are clearly visible in contrasting color combinations (black, red, white; orange, white, black, etc.). Many insects have warning coloration, for example soldier bugs, ladybugs, bronzovki, leaf beetles, bladders, various butterflies — variegated bears and etc.

Among vertebrates, warning coloration is observed in fish, salamanders, toads toads, in some birds ( drongo), and among mammals - for example, in american skunk... The visibility of animals with warning coloration is their advantage as they are unrecognizable and are not attacked by predators. The warning coloration contributes to the survival of the species in the struggle for existence and is the result of the action of natural selection.

Mimicry(Greek. mimikos- imitative) - imitative similarity of an unprotected organism with a protected or inedible one.

In animals, mimicry promotes survival in the struggle for existence. Mimicry can be not only aimed at passive defense, but also serve as a weapon of attack, luring prey.

Demonstrative behavior- one of the means of communication in animals. Making various body movements, for example, birds in mating season show each other certain areas of plumage, with a bright signal color that carries information.

Demonstrative behavior is used to attract mating partners, during courtship, conflicts with rivals, protecting nests, communicating with chicks, capturing and defending territories, as well as a means of warning of danger.

Of great importance for the survival of organisms is adaptive behavior. Seasonal animal migration is an example of adaptive behavior.

Seasonal moltassociated with seasonal changes in the living conditions of animals.In animals that do not fall into hibernation, autumn and spring molt is observed annually.

During the autumn molt, the heat-conducting hairline is replaced by thick, warm fur. During the spring molt, simultaneously with the replacement of the cover in many animals, the upper part of the stratum corneum of the epidermis sloughs off.

Animal feed storage- an important instinct, most developed in the inhabitants of cold and temperate latitudes with sharp seasonal changes in feeding conditions. It is observed in many invertebrates, in some birds, and especially in mammals. Some spiders, crabs, crayfish and many insects store food from invertebrates.

Of the birds, only wintering birds store food. Most birds use the stocks in winter as additional food.

Some predators, pikas and many rodents store food from mammals. The reserves are used in winter or spring after awakening from hibernation or winter sleep.

Steppe polecat puts gophers in a hole, ermine- water rats, mice, frogs, weasel- small rodents. Many pikas prepare hay by stacking it in stacks or in gaps between stones. Squirrel stores mushrooms, nuts and acorns. Chipmunk pulls nuts, grains into his hole, wood mouse- seeds, river beaver- branches and rhizomes, immersing them in water near the entrance to the burrow.

Adaptations are the properties and characteristics of organisms that provide adaptation to the environment in which these organisms live. Adaptation is also called the process of the emergence of adaptations.

How did all these amazing devices come about? It is unlikely that a single mutation could provide such an exact match between an insect's wing and a living leaf, between a fly and a bee. It is incredible that a single mutation would cause a patronizingly colored insect to hide on exactly the leaves that it looks like. It is obvious that such adaptations as protective and warning colors and mimicry arose through the gradual selection of all those small deviations in body shape, in the distribution of certain pigments, in innate behavior that existed in the populations of the ancestors of these animals. One of the most important characteristics of natural selection is its cumulativeness - its ability to accumulate and enhance these deviations in a series of generations, adding up changes in individual genes and the systems of organisms controlled by them. Kogan V.L. and other Biology. M .., 2008.S. 142.

The most interesting and difficult problem is the initial stages of the emergence of adaptations. It is clear what advantages the almost perfect resemblance of a praying mantis to a dry knot gives. But what advantages could his distant ancestor, who only vaguely resembled a twig, have? Are predators so stupid that they can be fooled so easily? No, predators are not at all stupid, and natural selection from generation to generation "teaches" them better and better to recognize the tricks of their prey. Even the perfect resemblance of a modern praying mantis to a knot does not give it a 100% guarantee that no bird will ever notice it. However, its chances of eluding a predator are higher than that of an insect with a less perfect protective coloration. Likewise, his distant ancestor, only a little bit like a bitch, had a slightly higher chance of life than his relative did not look like a bitch at all. Of course, the bird that sits next to him will easily notice him on a clear day. But if the day is foggy, if the bird does not sit nearby, but flies by and decides not to waste time on what may be a praying mantis, or maybe a knot, then a minimal similarity keeps the bearer of this barely noticeable similarity alive. His descendants who will inherit this minimal similarity will be more numerous. Their share in the population will increase. This will make life difficult for the birds. Among them, those who will more accurately recognize camouflaged prey will become more successful.

Natural selection picks up all those minute changes that enhance the similarity in color and shape with the substrate, the similarity between an edible species and that inedible that he imitates. It should be borne in mind that different types predators use different methods of finding prey. Some pay attention to shape, others to color, some have color vision, others do not. Therefore, natural selection automatically enhances, as much as possible, the similarity between simulator and model and leads to those amazing adaptations that we observe in wildlife. Kogan V. L. et al. Biology. M .., 2008.S. 149.

The emergence of complex adaptations. Many adaptations come across as carefully thought out and targeted devices. How is this complex structure How could the human eye have arisen by natural selection of randomly occurring mutations?

Scientists suggest that the evolution of the eye began with small groups of light-sensitive cells on the surface of the body of our very distant ancestors, who lived about 550 million years ago. The ability to distinguish between light and darkness was, of course, useful for them, increased their chances of life in comparison with their completely blind relatives. The accidental curvature of the "visual" surface improved vision, this made it possible to determine the direction to the light source. An eye cup appeared. Newly emerging mutations could lead to narrowing and widening of the optic cup opening. The narrowing gradually improved vision - the light began to pass through a narrow aperture. As you can see, each step increased the fitness of those individuals that changed in the "right" direction. The light-sensitive cells formed the retina. Over time, a lens has formed in the front of the eyeball, which acts as a lens. It appeared, apparently, as a transparent two-layer structure filled with liquid.

We can find all the supposed stages of evolution of the human eye among living animals. The evolution of the eye went in different ways in different types animals. Through natural selection, many different forms of the eye have emerged independently, and the human eye is only one of them, and not the most perfect.

If we look closely at the structure of the eye in humans and other vertebrates, we find a whole series of strange incongruities. When light enters a person's eye, it passes through the lens and hits the light-sensitive cells of the retina. Light is forced to break through a dense network of capillaries and neurons to reach the photoreceptor layer. Surprisingly, but the nerve endings approach the light-sensitive cells not from behind, but from the front! Moreover, the nerve endings are collected in the optic nerve, which departs from the center of the retina, and thereby creates a blind spot. To compensate for the shading of photoreceptors by neurons and capillaries and get rid of the blind spot, our eye constantly moves, sending a series of different projections of the same image to the brain. Our brain performs the most complex operations, adding these images, subtracting shadows, and calculating the real picture. Kogan V.L. and other Biology. M .., 2008.S. 150.