The emergence of devices. Relative character of adaptability

Species of plants and animals are remarkably adapted to the conditions of the environment in which they live. A huge number of the most diverse features of the structure are known, providing high level adaptation of the species to the environment. In the concept " fitness of the species" include not only external signs, but also conformity buildings internal organs the functions they perform, such as the long and complex digestive tract of plant-eating animals (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.

Adaptive features of the structure, body color and behavior of animals. In fact, the entire structural and functional organization of representatives of a particular species is adaptive to the conditions in which this group lives. The structure of the body and the color of the integument are most demonstrative.

Body shape. In animals, the shape of the body is adaptive to the environment. The appearance of the aquatic mammal dolphin is well known. His movements are light and precise. Independent speed in water reaches 40 km / h. Often, cases are described of how dolphins accompany high-speed sea vessels, for example, destroyers moving at a speed of 65 km / h. This is explained by the fact that dolphins attach themselves 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 the dolphin manage to overcome it? In addition to other structural features, the shape of the body contributes to the ideal adaptability of the dolphin to the environment and lifestyle. The torpedo-shaped body shape avoids the formation of a swirl of water flows around the dolphin.

The streamlined shape of the body contributes to the rapid movement of animals in the air. Flight and contour feathers covering the bird's body completely smooth its shape. Birds do not have protruding auricles, in flight they usually retract their legs. As a result, birds are far superior in speed to all other animals. For example, a peregrine falcon dives on its prey at speeds up to 290 km/h. Birds move quickly even in water. A chinstrap penguin has been observed swimming underwater at about 35 km/h.

Animals that lead a secretive, hiding way of life are useful adaptations that give them a resemblance to objects. environment. The bizarre body shape of fish living in thickets of algae helps them successfully hide from enemies. Resemblance to objects of the environment is widespread in insects. Beetles are known for their appearance reminiscent of lichens, cicadas, similar to the thorns of those shrubs among which they live. Stick insects look like a small brown or green twig (Fig. 19.5), while orthoptera imitate a leaf. Flat body have fish leading a benthic lifestyle.

Rice. 19.5.

Body coloration. It serves as a defense against enemies protective coloration. Patronizing is the coloring of the integuments of the body, which ensures their owners success in the struggle for existence. Usually, scientists distinguish between concealing or, conversely, warning coloring. Birds that incubate 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 (Fig. 19.6). 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 that lay their eggs on rocks or bury them in the ground, the protective color of the shell does not develop.

Rice. 19.6.

offspring on earth

Protective coloration is widespread among a wide variety of animals. Butterfly caterpillars are often green, the color of the leaves, or dark, the color of the bark or earth. Bottom fish are usually painted to match the color of the sandy bottom (stingrays and flounders). At the same time, flounders are also able to change color depending on the color of the surrounding background. The ability to change color by redistributing the pigment in the integument of the body is also known in terrestrial animals (chameleon). Desert animals are usually yellow-brown or sandy-yellow in color. Monochromatic protective coloration characteristic of both insects (locusts) and small lizards, as well as large ungulates (antelopes) and predators (lions).

If the background of the environment does not remain constant depending on the season, 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.

Two-tone cloaking is often seen in aquatic animals. So, in most fish, for example, in herring, the back is strongly pigmented, and the ventral side of the body is light. If you look at the fish from above, from a zone of greater illumination, then against the background of the deepening darkness, the dark back is almost invisible. On the contrary, when viewed from the depth - in the direction of greater illumination - the abdomen is imperceptible. This coloration is also important for predators (dolphins, sharks, etc.) and for their victims.

Another variant of concealing coloration is dissecting coloration. It is characterized by the alternation of dark and light stripes and spots on the body, corresponding to the change of light and shadow in the habitat habitual for the species (Fig. 19.7). Such a coincidence makes the organism imperceptible due to the violation of the idea of its form. For example, the tiger hunts in ambush at the edges, where tufts of yellow grass alternate with dark soil. Zebra, feeding on the foliage of shrubs, in the savannah is almost invisible against the background of multi-stem. In addition, dissecting coloring breaks the idea of the contours of the body, which makes it even more effective.

Rice. 19.7.

However, often in animals there is a body color that does not hide, but, on the contrary, attracts attention, unmasks. This coloration is characteristic of poisonous, burning or stinging insects: bees, wasps, blister beetles. A ladybug, very noticeable, is never pecked by birds because of the poisonous secret secreted by insects. Inedible caterpillars, many poisonous snakes have a bright warning color. Bright coloring warns the predator in advance about the futility and danger of the attack. Through trial and error, predators quickly learn to avoid attacking prey with warning paint.

The effectiveness of cautionary coloration was the cause of a very interesting phenomenon - imitation, or mimicry(from Greek. mimicos- imitative). Mimicry is called resemblance defenseless or edible type with one or more unrelated species, well protected and with warning coloration. One of the species of cockroaches is very similar to the ladybug in size, body shape and distribution of age spots. Some edible butterflies imitate the body shape and coloration of poisonous butterflies, flies - wasps. The occurrence of mimicry is associated with the accumulation under control natural selection small successful mutations in edible species in the conditions of their coexistence with non-edible ones.

It is clear that the imitation of some species by others is justified: a much smaller part of the individuals of both the species that served as a model and the imitator species are exterminated. It is necessary, however, that the number of the imitator species be significantly less than the number of the model. Otherwise, mimicry is of no use: the predator will not develop a strong conditioned reflex to a shape or color that should be avoided. How is the abundance of the mimic species kept at a low level? It turned out that the gene pool of these species is saturated with lethal mutations. In the homozygous state, these mutations cause the death of insects, as a result of which a high percentage of individuals do not survive to sexual maturity.

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

Behavior. For the survival of organisms in the struggle for existence great importance has adaptive behavior. The protective effect of warning coloration is enhanced when it is combined with appropriate behavior. For example, the bittern nests in the reeds. In moments of danger, she stretches her neck, raises her head up and freezes. In this position, it is difficult to detect even at close range. Many other animals that do not have means of active protection, in case of danger, take a resting position and freeze (insects, fish, amphibians, birds). The warning coloration in animals, on the contrary, is combined with a demonstrative behavior that frightens off a predator.

In addition to hiding or demonstrative, intimidating behavior when the enemy approaches, there are many other options. adaptive behavior, ensuring the survival of adults or juveniles. This includes storing food for the unfavorable season of the year. This is especially true for rodents. For example, the housekeeper vole, common in the taiga zone, collects grains of cereals, dry grass, roots - up to 10 kg in total. Burrowing rodents (mole rats, etc.) accumulate up to 14 kg of pieces of oak roots, acorns, potatoes, steppe peas. Greater gerbil living in deserts Central Asia, at the beginning of summer, cuts the grass and drags it into holes or leaves it on the surface in the form of stacks. This food is used in the second half of summer, autumn and winter. The river beaver collects stumps of trees, branches, etc., which he puts into the water near his dwelling. These warehouses can reach a volume of 20 m 3 . Feed stocks are also made by predatory animals. Mink, some ferrets and canines store frogs, snakes, small animals, etc., killing them and burying them in certain places.

An example of adaptive behavior is the time of greatest activity. In the deserts, many animals come out to hunt at night when the heat subsides. The specialization of animal activity according to the time of day has led, for example in birds, to the emergence of entire ecological groups of species. So, "night predators" (owls, eagle owls, etc.) hunt at night, and "daytime" - falcon, golden eagle, eagle - in daylight.

Anchor points

The whole organization of any kind of living organisms is adaptive to the conditions in which it lives.
Adaptations of organisms to the environment are manifested at all levels of organization: biochemical, cytological, histological and anatomical.
Physiological adaptations are an example of reflecting the structural features of an organization in given conditions of existence.

1. Give examples of the adaptability of organisms to the conditions of existence.
2. Why do some animal species have a bright unmasking color?
3. What is the essence of the phenomenon of mimicry?
4. How is the low number of mimic species maintained?
5. Does the action of natural selection extend to the behavior of animals? Give examples.

Caring for offspring. Of particular importance are devices that protect offspring from enemies. Care for offspring can be manifested in different forms. Many fish guard the eggs that are deposited between the stones, actively driving away and biting the approaching possible enemies. Azov and Caspian gobies lay their eggs in holes dug in the muddy bottom, and then guard it throughout their development. The male stickleback builds a nest with an entrance and an exit. Some American catfish stick caviar on their belly and carry it around all the time of development. Many fish hatch eggs in their mouths or even in their stomachs. During this time, the parent does not eat anything. The hatched fry stay close to the female (or male, depending on the species) for some time and, in case of danger, hide in the mother's mouth. There are species of frogs in which eggs develop in a special brood pouch on the back or in the vocal sacs of the male.

The greatest safety of the offspring is obviously achieved when the embryos develop in mother's body(Fig. 19.8). Fertility in these cases (as in other forms of care for offspring) decreases, but this is compensated by an increase in the survival rate of juveniles.

Rice. 19.8.

In arthropods and lower vertebrates, the resulting larvae lead an independent lifestyle and do not depend on their parents. But in some cases, parental concern for offspring is manifested in the form providing them with food. The famous French naturalist J.A. Fabre first described this behavior in solitary wasps. Wasps attack beetles, spiders, crickets, praying mantises, caterpillars of various butterflies, immobilize them by plunging the sting exactly into the nerve nodes (Fig. 19.9), and lay eggs on them.

Rice. 19.9.A single wasp drags a paralyzed grasshopper into its nest: the future larva is provided with food

The hatching wasp larvae are provided with food: they feed on the tissues of a living victim, grow and then pupate.

The described examples of care for offspring in arthropods and lower vertebrates occur in a very small number of species. In most cases, fertilized eggs are left to fend for themselves. This explains the very high fecundity of invertebrates and lower vertebrates. A large number of offspring in conditions of high exterminability of juveniles serves as a means of struggle for the existence of the species as a whole.

Significantly more complex and diverse forms of care for offspring are observed in higher vertebrates. Complex instincts and ability to individual training allow them to raise offspring with much greater success. So, birds lay fertilized eggs in special facilities - nests, and not just to the environment, as all kinds of lower classes do. The eggs develop under the influence of the heat imparted to them by the body of the parents, and do not depend on the accidents of the weather. Parents protect the nest from enemies in one way or another. Most of the bird species do not leave hatched chicks to the mercy of fate, but feed and protect them for a long time. All this sharply increases the efficiency of reproduction in this group of animals.

The highest degree of development is achieved by the forms of behavior in mammals. This also manifests itself in relation to the cubs. Animals not only feed their offspring, but also teach them to catch prey. Darwin also noted that predatory animals teach their cubs to avoid dangers, including hunters.

Thus, individuals with more advanced forms of care for offspring survive in greater numbers and pass these traits on from generation to generation.

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

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

A variety of physiological adaptations to life in adverse conditions have been developed by birds and mammals. Many desert animals accumulate a lot of fat before the onset of the dry season: when it is oxidized, a large amount of water is formed. Birds and mammals are able to regulate water loss from the surface of the respiratory tract. For example, a camel, deprived of water, drastically reduces evaporation both from the respiratory tract and through the sweat glands.

A person’s salt metabolism is poorly regulated, and therefore he cannot do without salt for a long time. fresh water. But reptiles and birds conducting most living in the sea and drinking sea water, acquired special glands that allow them to quickly get rid of excess salts.

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

Through natural selection, adaptations arise and improve to facilitate the search for food or a partner for reproduction. The chemical organs of insects are amazingly sensitive. Male gypsy moths are attracted by the smell of the scent gland of a female from a distance of 3 km. In some butterflies, the sensitivity of taste receptors is 1,000 times greater than the sensitivity of human tongue receptors. Nocturnal predators such as owls have excellent vision in low light conditions. Some snakes have a well-developed ability to thermolocation. They distinguish objects at a distance if the difference in their temperatures is only 0.2 ° C. Many animals are perfectly oriented in space with the help of echolocation ( the bats, owls, dolphins).

The relative nature of the fitness of organisms. The structure of living organisms is very finely adapted to the conditions of existence. Any species trait or property that is adaptive in nature is appropriate in a given environment, in given living conditions. So, all the features of the structure and behavior of a cat are appropriate for a predator lying in wait for prey in ambush: soft pads on the fingers and retractable claws that make the gait noiseless; a huge pupil and high sensitivity of the retina, allowing you to see in the dark; subtle hearing and movable auricles, making it possible to accurately determine the location of the victim; the ability to wait for the appearance of prey for a long time and make a lightning jump; sharp teeth holding and tearing the victim. In the same way, the organization of carnivorous plants is adapted to catching and digesting insects and even small vertebrates (Fig. 19.10).

Rice. 19.10.

Adaptations do not appear ready-made, but are the result of a selection of random hereditary changes that increase the viability of organisms under specific conditions.

None of the adaptive traits provide absolute security for their owners. Due to mimicry, most birds do not touch wasps and bees, but there are species among them that eat both wasps and bees, and their imitators. The hedgehog and the secretary bird eat snakes without harm. The shell of terrestrial turtles reliably protects them from enemies, but birds of prey lift them into the air and smash them on the ground.

Any adaptations are expedient only in the usual environment for the species. When environmental conditions change, they turn out to be useless or harmful to the body. The constant growth of rodent incisors is a very important feature, but only when eating solid food. If a rat is kept on soft food, the incisors, without wearing out, grow to such a size that feeding becomes impossible.

Thus, any structure and any function is an adaptation to the external environment characteristic of the species or, as modern scientists say, "here and now." Evolutionary changes - the formation of new populations and species, the emergence or disappearance of organs, the complication of organization - are due to the development of adaptations. The expediency of living nature is the result of the historical development of species under certain conditions, therefore it is always relative and has a temporary character.

Anchor points

Care for offspring arises as a way to ensure the survival of the species against the background of a high degree of development of the nervous system and is one of the forms of physiological adaptations.
Any adaptations, including those caused by behavioral reactions, are relative and appropriate only in specific conditions of existence.

Questions and tasks for repetition

1. Why do species of animals that care for offspring have fewer offspring? Give examples.
2. What is relative nature adaptive traits in organisms? Give examples specific to plants and animals.

The adaptability of organisms is the result of natural selection. Prepared by Chiritso Elizaveta, a student of the 11th "M" class.

it is a combination of those features of the structure, physiology and behavior that provide for a given species the possibility of a specific lifestyle in certain environmental conditions. Adaptation -

How are adaptations formed? C. Linnaeus: Species are created by God and are already adapted to their environment. J. B. Lamarck: the formation of fitness by the desire of organisms for self-improvement. Charles Darwin: explained the origin of fitness in the organic world with the help of natural selection.

Adaptations to the environment are manifested in the external and internal structure, life processes, behavior. The shape of the body of various animals is an example of the adaptability of organisms to the environment. The protective coloration and body shape of some animals make them invisible against the background of the environment, masking them. Some animals have bright color, which sharply distinguishes them from the background of the environment. This coloring is called warning. Some defenseless and edible animals imitate species that are well protected from predation. This phenomenon is called mimicry. Protection against eating is characteristic of many animals and plants. They protect themselves. Behavioral adaptations are changes in the behavior of animals in certain conditions: care for offspring, the formation of separate pairs during the mating season, and in winter they unite in flocks, which facilitates food and protection, frightening behavior, freezing, imitation of injury or death, hibernation, food storage . The adaptability of life processes to living conditions are called physiological adaptations: the accumulation of fat by desert animals, glands that get rid of excess salts, thermal location, echolocation. Biochemical adaptations are associated with the formation in the body of certain substances that facilitate defense against enemies or attacks on other animals.

Forms of adaptations Examples Description of adaptations Body shape Protective coloration (camouflage) Warning coloration Mimicry Behavioral adaptations Classification of adaptations

Body shape The streamlined shape of the body allows the dolphin to reach a speed of 40 km / h in the water. The peregrine falcon, in pursuit of prey, develops a speed of 290 km / h. The speed of the penguin in the water column is 35 km / h.

Protective coloration (camouflage) In openly nesting birds, the female sitting on the nest is almost indistinguishable from the surrounding background. Corresponds to the background and pigmented egg shells. Interestingly, in birds nesting in hollows, on trees, females often have a bright color, and the shell is light. Quail and its eggs Redstart, cuckoo egg in redstart nest

Protective coloration (camouflage) A surprising resemblance to twigs is observed in stick insects. The caterpillars of some butterflies resemble knots, and the body of some butterflies is like a leaf. The effect of protective coloration is enhanced when it is combined with the appropriate behavior: at the moment of danger, many animals freeze, taking a resting pose.

Warning coloration Very bright coloration (usually white, yellow, red, black) is characteristic of well-protected poisonous, stinging forms. Having tried several times to taste the “soldier” bug, ladybug, wasp, the birds eventually refuse to attack the victim with a bright color. sand efa Bedbug - ladybug soldier

Mimicry The viceroy butterfly repeats the shape and color of the wings of the poisonous monarch butterfly. The fly mimics the appearance and behavior of the bee This is the similarity of a defenseless or edible species with a well-protected and warning color

Mimicry The milk snake successfully imitates the coloration of the coral snake. As a rule, the number of copied individuals is many times higher than the copying ones.

Behavioral adaptations A characteristic feature of the opossum's behavior is the ability to pretend to be dead in danger, in this "game" the opossum is simply inimitable. changes in behavior in certain conditions Frog paws. The desert amphibian, which lives most of its life in burrows, goes hunting at night when the heat subsides.

Behavioral Adaptations River beaver stores up to 20 cubic meters. fodder Male stickleback builds a nest with 2 exits - care for the safety of offspring

The relative nature of fitness Poisonous snakes, dangerous to many animals, are eaten by mongooses. The hedgehog defends itself from the fox with needles and curls up into a ball, but if there is a stream nearby, the fox rolls it into the water, where the muscles of the hedgehog open up and it becomes easy prey.

1. Adaptability of organisms to the environment, its causes. The relative nature of the fitness of organisms. The adaptability of plants to the use of light in biogeocenosis.

2. Changes in the biosphere under the influence of human activities. Maintaining balance in the biosphere as the basis of its integrity.

3. Solve the problem of the intermediate nature of inheritance.

1. Adaptability - correspondence of the structure of cells, tissues, organs, organ systems to the functions performed, signs of the organism to the environment. Examples: the presence of cristae in mitochondria - an adaptation to the location on them of a large number of enzymes involved in the oxidation of organic substances; the elongated shape of the vessels, their strong walls - adaptability to the movement of water along them with minerals dissolved in it in the plant. The green color of grasshoppers, praying mantises, many caterpillars of butterflies, aphids, herbivorous bugs is an adaptation to protection from being eaten by birds.

2. Causes of fitness - the driving forces of evolution: hereditary variability, the struggle for existence, natural selection.

3. The emergence of adaptations and its scientific explanation. An example of the formation of fitness in organisms: insects did not previously have a green color, but were forced to switch to feeding on plant leaves. Populations are heterogeneous in color. Birds ate highly visible individuals, individuals with mutations (the appearance of green tints in them) were less visible on a green leaf. During reproduction, new mutations arose in them, but individuals with green tones were predominantly preserved by natural selection. After many generations, all individuals of this population of insects acquired a green color.

4. The relative nature of fitness. Signs of organisms correspond only to certain environmental conditions. When conditions change, they become useless and sometimes harmful. Examples: fish breathe with gills, through which oxygen enters the blood from the water. On land, fish cannot breathe because oxygen from the air does not enter the gills. The green color of insects saves them from birds only when they are on the green parts of the plant, on a different background they become visible and not protected.

5. The tiered arrangement of plants in a biogeocenosis is an example of their adaptability to the use of light energy. Placement in the first tier of the most light-loving plants, and in the lowest - shade-tolerant (fern, hoof, oxalis). The dense closing of crowns in forest communities is the reason for the small number of tiers in them.

2. 1. The biosphere is a holistic, relatively stable, gigantic ecological system, the dependence of the balance that has historically developed in it on the connections between its inhabitants, their adaptability to the environment, on the role of living matter in the biosphere, on the influence of human activity.

2. Reasons global change in the biosphere: population growth, development of industry, road, rail, air transport, the emergence of complex road networks, intensive mining, construction of power plants, development Agriculture and etc.

3. Negative Consequences development of industry, transport, agriculture - pollution of all living environments (land-air, water, soil), loss of soil fertility, reduction of arable land, destruction of large areas of forests, the disappearance of many species of plants and animals, the emergence of new pathogens dangerous to human life diseases (AIDS viruses, infectious hepatitis, etc.), reduction of clean water supplies, depletion of fossil resources, etc.

4. Pollution of the biosphere as a result of agricultural activities. The use of high doses of pesticides is the cause of soil pollution, water in reservoirs, a decrease in the number of animal species living in them, slowing down the vital activity of decomposers (they destroy organic residues and turn them into suitable for food).

plant minerals). Violation of application norms mineral fertilizers- the cause of soil pollution with nitrates, their accumulation in food, poisoning people with them.

5. Types of industrial pollution of the biosphere: 1) chemical - the release into the biosphere of hundreds of substances that were not previously in nature (acid rain, etc.); 2) radiation, noise, biological pollution, their negative impact on human health, on the living matter of the biosphere.

6. Rational nature management is the main way to protect the biosphere from pollution, save resources from depletion, save plant and animal species from extinction, maintain balance and integrity of the biosphere.

3. In solving the problem, one should proceed from the fact that in the first generation of hybrids, dominance will be incomplete, although the offspring will be uniform. It will appear not a dominant and not a recessive trait, but an intermediate one. For example, a night beauty plant will grow not with red and white flowers, but with pink ones. In the second generation, splitting will occur and three groups of individuals will appear according to the phenotype: one part with a dominant trait (red flowers), one part with a recessive trait (white flowers), two parts of heterozygotes with an intermediate trait (pink).

The fitness of organisms (adaptation) is a complex characteristic features, allowing to survive in a certain environment and leave numerous strong procreation.

Adaptation to emerging conditions is influenced by the driving forces of evolution. But conditions are never constant, they change, so all adjustments are relative.

A white partridge merging with snow is detected by a shadow. Organisms with new traits that operate within a certain range may simply die if they go beyond these boundaries. Only individuals that have adapted to the new environment in the course of natural selection remain to live.

Types of adaptability of organisms

TO morphological adaptations include:

Transformation of the body, namely: streamlining or flattening of the shape, webbed paws, thick hair.
With the help of disguise, you can become invisible against the background of the environment, become similar in color and shape to a leaf, stone, twig (insects, fish).
With a protective and dismembering coloration, one can merge with the environment in a changing situation (hare - hare, bird eggs, zebra).
Warning coloring is distinguished by a bright color, specks, stripes, and is needed to scare away or warn of an attack (bees, snakes, ladybugs).
To warn and protect oneself, a weak one, from a stronger one, becoming similar in color, body shape or behavior, is called mimicry (tropical snake, fly - murmuring, cuckoo eggs).

Physiological adaptations include:

Preparation for life in changing conditions: - the camel accumulates fat; - the formation of glands that get rid of excess salt (marine reptiles and birds). - location of heat and sound; - falling into hibernation.
Behavior: - the smaller the number of cubs, the more care for them for the purpose of conservation; - the formation of mating pairs for the period of reproduction of offspring and life in packs with complication of conditions (birds, wolves). - scaring away (cobra, grin and growl of a dog, smell of a skunk). - imitation of the wounded or dead, hiding (opossum, frog, bird). - prudence (winter sleep, food storage).
With the help of biochemical devices (special substance), the animal can defend itself or attack the enemy (poisons, antibiotic bacteria, special proteins and fats).

The nature of the fitness of organisms

Natural selection leaves only the fittest alive. But the slightest change in the environment can render useless or even harmful those devices that worked well before.

As a result, those organisms that have managed to adapt faster survive, and those who are late die out, making it possible for a new species to form. Such adaptations are formed for a very long time in a natural way and are relative, because the conditions of life change much faster than the necessary changes appear in animals.

Evidence for the relativity of fixtures:

methods of protection are not universal (dangerous for some poisonous snake eats mongoose, hedgehog);
in some cases, instinct fails (a night butterfly flies for nectar to a light flower, or it can confuse it with fire);
an organ that is necessary in one environment is useless or harmful in other conditions (mountain geese with membranes they do not need);
the fish is adapted to separate oxygen from the water, on land it cannot do this; - green insects are not visible on the grass, on clean ground they will be quickly eaten.

Causes of adaptability of organisms

It has been established that individuals of a species will survive if they change faster, adapting to new environmental requirements. The emergence of new characters and the appearance of a new species is called phyletic speciation.

Today, the diversity of species has noticeably decreased compared to several thousand years ago. This is due to constant climate change, ice ages, volcanic eruptions, earthquakes, deterioration environmental situation, the barbaric attitude of the people. As a result, the most adapted organisms survive, and the main reason for adaptability belongs to natural selection.

Adaptation of organisms to the environment

To survive, you need to adapt to the conditions of life, and she will choose the best individuals and remove the weak. All animals live in different parts of nature and their adaptive features depend on this.

Laboratory work fitness of organisms

Laboratory work, with a problematic situation in the content, is necessary for the development of independent skills for studying and researching objects of biology. The existing problem generates hypotheses, versions, proofs and teaches to draw conclusions. Each work has a goal, questions, tasks and applications. And the progress of work is more convenient to display in the table.

Example. L. r. "Adaptation to the environment".

Target: to define the concept of the adaptability of animals, to train the ability to determine adaptations.

Fly - hoverfly can be found everywhere, except for the tundra and the desert. It is a short-whiskered two-winged insect similar to a wasp, but completely harmless. Hoverflies fly very fast. Their relationship with ants, bumblebees leading a social lifestyle has been proven.

Adaptability of organisms to environmental factors

Any living organisms are affected natural factors. TO inanimate nature include: temperature, change of day and night, seasons, soil features, landscape, chemical composition air and water, noise, radiation. Organisms adapt to this, but they cannot influence these conditions, which are called abiotic factors.

Of no small importance for the survival of animals are adaptations to changes in nature by man (anthropogenic factor). Being in natural communities, all living inhabitants of the planet are divided into groups with similar signs of adaptation to a single environmental factor. These changes can be expressed both externally and internally, with a change in the nature of behavior.

For example, body temperature depends on weather conditions in most representatives of the animal world. These are cold-blooded animals. They react either by decreasing or increasing the metabolic rate. When slowed down, they experience suspended animation, which helps to conserve energy. In warm-blooded species, the temperature is always constant and does not affect metabolism. There are predators that hunt during the day, and there are those that come out only at night. Pets are active mainly during the daytime.

Examples of the fitness of organisms

The horse can run fast with wide, comfortable hooves. Cats are able to silently sneak up, pulling in their claws. Birds lightened their body for flight, getting rid of the bladder, one ovary, teeth and acquiring wings with different plumage.

Insects - caterpillars have adapted to become like a leaf of a plant, a twig. Crocodiles have special glands near their eyes that help remove excess salt. The camel stores fat in its humps, which breaks down to release water. Polar bear retains heat with a layer of subcutaneous fat and thick fur, wide paws allow you to walk on thin ice.

The study of the fitness of organisms

Initially, during the reign of religion, it was argued that all life on Earth was created by the existing wise God. That nature itself could not do this. The Creator created everyone in such a way that they could do what was entrusted to them. K. Linnaeus also adhered to this theory.

J. B. Lamarck argued that all organisms are born with the ability to change, and throughout their lives they can only improve these skills. Thus, new species with useful properties arise. But this theory does not explain the different colors of bird eggs and the benefits of thorns for hedgehogs.

C. Darwin expressed his opinion; “... if an animal or plant can survive a sharp change in climate or other conditions, then it is its descendants that will become the most common.” A new emerging trait is passed on to offspring if it contributes to survival.

Modern scientists, studying adaptation, have come to the conclusion that any useful variability comes later than the right time. Some new signs even harm the animal in suddenly changed conditions.

Pronghorns rank second among all animals in terms of running speed. But a special feature is the muscles that change the slope of the coat. This ability helps in heat or cold. And most importantly, seeing the danger, the observer fluffs up the hair of his backside, which immediately notices the whole herd.
The secret of toothfish, an Antarctic fish, is that with the help of a special protein that acts as an antifreeze, its blood remains unfrozen even at a temperature of minus 2 degrees.
African protopter fish, which can sleep up to 4 years, will be envied even by a bear. It is a lungfish, having, along with gills, also a pulmonary system.
Toad - the water carrier sleeps in its shelter of slime, waiting for a new rain, as many as seven.
The vulture bird is not only a nurse - it eats carrion, but it can also cool its body by urinating on its plumage.

conclusions

Each organism is best adapted to the conditions where it has to live. This change only serves where it was purchased and is therefore considered relative. Natural selection leaves individuals with only those traits that have withstood the greatest deviation in the significance of a certain environmental factor.

Natural selection always has the character of an adaptive reaction to the conditions of existence. All signs of living organisms are adapted to the conditions of their existence. Adaptability is distinguished by the internal and external structure of organisms, the behavior of animals, etc.

So, for example, the intensity of reproduction is higher in those creatures whose offspring in their mass dies. Cod, not taking care of their offspring, lays about 5 million eggs during the spawning period. The female of a small sea fish, a fifteen-spined stickleback, whose male guards the nest with eggs, lays only a few dozen eggs. The elephant, whose offspring in nature is almost never threatened, during her long life brings no more than 6 elephant calves, but the human roundworm, the vast majority of whose offspring dies, lays 200 thousand eggs every day during the year.

Wind pollinated plants produce huge amounts of fine, dry, very light pollen. The stigmas of the pistils of their flowers are large and feathery in shape. All this helps them pollinate more efficiently. And in insect-pollinated plants, pollen is much less, it is large and sticky, their flowers have nectaries and bright colors to attract pollinating insects.

Vivid examples of fitness are protective coloration and mimicry. Mimicry - imitation dangerous species seen in many animals. For example, some harmless non-venomous snakes have acquired a significant resemblance to their venomous relatives, which helps them avoid predation.

Darwin's theory explains the emergence of fitness by hereditary variability and natural selection.

However, one should always keep in mind that fitness is relative. That is, any adaptation helps to survive only in the conditions in which it was formed. As soon as the conditions change, a previously useful trait will turn into a harmful one and lead to death. For example, a beautifully flying swift has very long narrow wings. However, this specialization of the wing has led to the fact that the swift cannot take off from flat surfaces and, if it has nothing to jump off, it dies.

The relative nature of fitness can also be considered in the following example: in the industrial regions of Europe, where, due to the intensive development of production, light-colored lichens that covered tree trunks died, dark-colored individuals of butterflies replaced light-colored individuals. This phenomenon is called industrial melanism. The fact is that light insects are very clearly visible against a dark background and are mainly eaten by birds. And in rural areas, on the contrary, dark insects are clearly visible on light trunks, and it is they that are destroyed by birds. Thus, natural selection marked the beginning of divergence (divergence) within a species, which can lead first to the appearance of subspecies, and then to new species.

The formation of new species is the most important stage in the evolutionary process.

The evolutionary process is divided into micro- and macroevolution. Microevolution is a process of restructuring within a species, leading to the formation of new populations, subspecies, and ending in the formation of new species.

Thus, microevolution is the very initial stage of the evolutionary process, which can take place in relatively short periods of time and which can be observed and studied directly.

As a result of hereditary (mutational) variability, random changes in the genotype occur. The spontaneous mutation rate is quite high, and 1-2% of germ cells have mutated genes or altered chromosomes. Mutations are most often recessive and rarely beneficial to the species. However, if as a result of a mutation beneficial changes occur for any individual, then it receives some advantages over other individuals of the population: it receives more food or becomes more resistant to the influence of pathogenic bacteria and viruses, etc. For example, the emergence of a long neck allowed the ancestors of the giraffe to eat leaves with tall trees, which provided them with more food than individuals of the population with a short neck.

Thus, with the emergence of a new trait, the process of divergence begins, that is, the divergence of traits within the population.

In a population of any species, there are waves of abundance. In favorable years, the population increases: intensive reproduction occurs, most young and old individuals survive. In unfavorable years, the population size can drop sharply: many individuals, especially young and old, die, and the intensity of reproduction decreases. Such waves depend on many factors: climate change, the amount of food, the number of enemies, pathogens, etc. In years that are unfavorable for the population, conditions may arise when only those individuals that, as a result of mutation, have acquired a useful trait, will survive. For example, during a drought, short-necked giraffe ancestors could starve to death, and long-necked individuals and their offspring began to dominate the population. Thus, in a fairly short period of time, as a result of natural selection, a “long-necked” population of artiodactyl animals could appear. But if individuals of this population could freely interbreed with "short-necked" relatives from neighboring populations, then a new species could not arise.

Thus, the next necessary factor of microevolution is the isolation of a population of individuals with a new trait that has arisen from a population of individuals that do not have this trait. Isolation can be done in several ways.

1. Geographic isolation as a factor in speciation. This kind

isolation associated with the expansion of the species habitat - range.

At the same time, new populations fall into different conditions compared to other populations: climatic, soil, etc. Hereditary changes constantly occur in a population, natural selection acts - as a result of these processes, the gene pool of the population changes, and a new subspecies arises. The free interbreeding of new populations or subspecies may be hindered by range gaps due to rivers, mountains, glaciers, etc. So, for example, on the basis of geographical isolation factors, a number of species arose from one species of lilies of the valley over several million years. This way of speciation is slow, occurring over hundreds, thousands and millions of generations.

2. Temporal isolation as a factor in speciation. This type of isolation is due to the fact that if the timing of reproduction does not coincide, two close subspecies will not be able to interbreed, and further divergence will lead to the formation of two new species. Thus, new species of fish arise if the timing of spawning of subspecies does not coincide, or new species of plants, if the timing of flowering of subspecies does not coincide.

3. Reproductive isolation as a factor of speciation. This type of isolation occurs when it is impossible to cross individuals of two subspecies due to a mismatch in the structure of the genital organs, differences in behavior, and incompatibility of the genetic material.

In any case, any isolation leads to reproductive disunity - i.e. to the impossibility of crossing the emerging species.

Thus, the process of microevolution can be divided into the following stages:

1. Spontaneous mutations and the onset of divergence within the same population.

2. Natural selection of the fittest individuals, continuation of divergence.

3. The death of less adapted individuals as a result of the influence of environmental conditions - the continuation of natural selection and the formation of new populations and subspecies.

4. Isolation of subspecies, resulting in the emergence of new species due to reproductive disunity.