What does the manifestation of the relative nature of fitness mean. The emergence of devices. ~ The relative nature of fitness. Microevolution. Speciation. Features of adaptability to the environment and their result

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 of dangerous species - is observed 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 feed on leaves from tall trees, which provided them with more food than individuals in 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 in 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. In a population, hereditary changes are constantly taking place, natural selection is operating - 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 in the event of a mismatch in breeding times, 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.

Topic: Adaptability of organisms to the environment and its relative nature.

Purpose: to form the concept of the adaptability of organisms to the environment, knowledge about the mechanisms of the emergence of fitness as a result of evolution.

During the classes.

1. Organizational moment.

2. Repetition of the studied material.

In the form of a frontal conversation, it is proposed to answer the questions:

What is the supplier of material for selection in a population?

Name the single driving force behind evolution.

In nature, there is a discrepancy between the ability of organisms to reproduce indefinitely and limited resources. Is this the reason...? struggle for existence, as a result of which the individuals most adapted to environmental conditions survive.

3. Study of new material.

one). Fitness.

- Evolution has three related consequences:

1. Gradual complication and increase in the organization of living beings.

2. Variety of species.

3. Relative fitness of organisms to environmental conditions.

? What do you think is the importance of fitness for an organism?

Answer: Adaptation to environmental conditions increases the chances of organisms to survive and leave a large number of offspring.

As you know, the most significant contribution to the development of evolutionary ideas in the 18-19 centuries. contributed by C. Linnaeus, J. B. Lamarck, C. Darwin.

-? The question arises, how are adaptations formed?

Let's try to explain the formation of an elephant's trunk from the point of view of C. Linnaeus, J.B. Lamarck, Ch. Darwin.

C. Linnaeus: the adaptability of organisms is a manifestation of the original expediency. God is the driving force. Example: Elephants, like all animals, were created by God. Therefore, all elephants from the moment of their appearance have a long trunk.

J.B. Lamarck : the idea of ​​the innate ability of organisms to change under the influence of the external environment. The driving force behind evolution is the striving of organisms for perfection. Example: Elephants, when getting food, had to constantly stretch their upper lip to get food (exercise). This trait is inherited. So there was a long trunk of elephants.

Ch.Darwin : among the many elephants were animals with trunks of different lengths. Those with slightly longer trunks were more successful at foraging and surviving. This trait was inherited. So, gradually, a long trunk of elephants arose.

Task: -Try to classify the proposed statements into three categories:

# Corresponds to the views of Linnaeus;

# Corresponds to the views of Lamarck;

# Corresponds to the views of Darwin.

1. Adaptations arise as a result of new mutations.

2. The adaptability of organisms is a manifestation of the original expediency.

3. Organisms have an innate ability to change under the influence of the external environment.

4. Adaptations are fixed as a result of natural selection.

5. One of the driving forces of evolution is the striving of organisms for perfection.

6. One of the driving forces of evolution is the struggle for existence.

7. One of the driving forces of evolution is the exercise or non-exercise of organs under certain environmental conditions.

8. The driving force behind the emergence of fitness is God.

9. Acquired during the interaction of an individual with the environment, the signs are inherited.

Answer: Linnaeus -2.8; Lamarck - 3.5.7.9; Darwin - 1,4,6.

For the first time, Ch. Darwin gave a materialistic explanation of the origin of fitness. Continuous natural selection plays a decisive role in the emergence of adaptations. Each adaptation is developed on the basis of hereditary variability in the process of the struggle for existence and natural selection in a number of generations.

ADAPTABILITY of organisms or adaptation - a set 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 mechanism:

Changing living conditions → individual hereditary variability → natural selection → fitness.

Types of adaptations:

1. Morphological adaptations (change in body structure): streamlined body shape in fish and birds; webbing between fingers in waterfowl; thick coat in northern mammals; flat body in demersal fish. Creeping and cushion-shaped form in plants in northern latitudes and high mountain regions.

2. Protective coloration. Protective coloration is developed in species that live openly and can be accessible to enemies. This coloration makes organisms less visible against the background of the surrounding area. Examples:

In the Far North, many animals are painted white (polar bear, white partridge).

–In zebra and tiger, dark and light stripes on the body coincide with the alternation of shadow and light of the surrounding area (hardly noticeable at a distance of 50-70 meters).

In openly nesting birds (grouse, black grouse, hazel grouse), the female sitting on the nest is almost indistinguishable from the surrounding background.

3. Disguise. Camouflage is a device in which the shape of the body and color of animals merge with surrounding objects. For example: the caterpillars of some butterflies resemble knots in body shape and color; insects living on the bark of a tree (beetles, barbels) can be mistaken for lichens; stick insect body shape; the merging of the flounder with the background of the seabed.

4 . Mimicry. Mimicry is the imitation of a less protected organism of one species by a more protected organism of another species. For example: some types of non-poisonous snakes and insects are similar to poisonous ones (the hoverfly fly is a wasp, tropical snakes are poisonous snakes). Snapdragon flowers are similar to bumblebees - insects are trying to establish a marriage relationship, which contributes to pollination. Mimicry is the result of selection for similar mutations in different species. It helps unprotected animals to survive, contributes to the preservation of the organism in the struggle for existence.

5. Warning (threatening) coloring. Bright warning coloration of well-protected poisonous, stinging forms: soldier bug, ladybug, wasp, Colorado potato beetle, bumblebee coloration, black and orange spots of caterpillars, etc.

6. Physiological adaptations: adaptability of life processes to living conditions; accumulation of fat by desert animals before the onset of the dry season (camel); glands that get rid of excess salts in reptiles and birds that live near the sea; water conservation in cacti; rapid metamorphosis in desert amphibians; thermal location, echolocation; a state of partial or complete anabiosis.

7. Behavioral adaptations: changes in behavior 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 (wolves, many birds); scare behavior (bombardier beetle, skunk); freezing, imitation of injury or death; hibernation, food storage.

8. Biochemical adaptations associated with the formation in the body of certain substances that facilitate defense against enemies or attacks on other animals; poisons of snakes, scorpions, antibiotics of fungi, bacteria; crystals of potassium oxalate in the leaves or spines of plants (cactus, nettle)

9. Adaptations to abiotic factors (for example, cold):

Animals : thick coat, thick subcutaneous fat, flight to the south, hibernation, storage of food for the winter.

In plants : leaf fall, cold resistance, preservation of vegetative organs in the soil, the presence of modifications (bulbs, rhizomes, etc. with a supply of nutrients).

10. Ways to get food.

Animals : - eating leaves on tall trees (long neck); capture with the help of trapping nets (weaving webs and creating various other traps) and lying in wait for food objects;

The special structure of the digestive organs for catching insects from narrow holes; catching flying insects; repeated chewing of rough food (sticky long tongue, multi-chambered stomach, etc.)

Grasping and holding prey by predatory mammals and birds (predatory teeth, claws, hooked beak).

In plants : intensive development of roots and root hairs → absorption of water and mineral salts; wide thin leaves, leaf mosaic→solar absorption; capture and digestion of small animals → carnivorous plants.

11. Protection from enemies.

In animals: fast run; needles, shell; frightening smell; patronizing. warning and other types of coloring; stinging cells.

In plants: spines; rosette form, inaccessible for mowing; toxic substances.

12. Ensuring the efficiency of reproduction.

Animals : attraction of a sexual partner: bright plumage, "crown of horns"; songs; marriage dances.

In plants : pollinator attraction: nectar; pollen; bright color of flowers or inflorescences, smell.

13. Settlement in new territories.

Animals : migration-movement of herds, colonies, flocks in search of food and suitable conditions for reproduction (bird flights, migrations of antelopes, zebras, fish swims).

In plants: dispersal of seeds and spores: tenacious hooks, spines; tufts, lionfish, wind-borne flyers; juicy fruits, etc.

2. The relative nature of fitness.

Even Ch. Darwin emphasized that all adaptations, no matter how perfect they are, are relative. Fitness is relative and any adaptation helps to survive only in the conditions in which it was formed. When conditions change, a previously useful trait can turn into a harmful one and lead to the death of the organism.

The following facts can serve as evidence for the relativity of adaptations:

The white partridge pretends to be a shadow on the snow. The white hare is visible against the background of dark trunks. The night butterfly flies to the fire (they collect nectar from light flowers at night). The wings of the swift provide it with a very fast and maneuverable flight, but do not allow it to take off if the bird accidentally ends up on the ground (swifts nest only on high cliffs). With a delay in snowfall, a hare that has molted for the winter in time is clearly visible against the background of dark earth. Small birds continue to spend their energy on feeding the cuckoo, which threw their offspring from the nest. The bright coloring of the male peacock ensures his success with females, but at the same time attracts predators.

In forest lands, hedgehogs collect more ticks, including encephalitis, than any other animals. With a needle-like “shell”, the hedgehog, like with a brush, combs the hungry ticks that have climbed onto the forest grasses. The hedgehog cannot get rid of ticks stuck between the needles. During the spring season, each hedgehog feeds tens of thousands of ticks. Thus, the spiny cover reliably protects the hedgehog from predators, but just as reliably protects ticks from the hedgehog itself.

Thus, fitness is not absolute, but relative.

The relative nature of fitness contradicts the assertion of absolute expediency in living nature (J.-B. Lamarck's evolutionary theory).

3. Fixing the material. Card work.

4. Homework item 58, questions.

Natural selection is the driving force behind evolution

Natural selection is a process that favors the survival of the fittest and the destruction of the less fit. More adapted individuals have the opportunity to leave offspring. The material for selection is individual hereditary changes. Harmful changes reduce the fecundity and survival of individuals, while beneficial ones accumulate in the population. Selection always has a directional character: it preserves those changes that are most consistent with environmental conditions, increase the fertility of individuals.

Selection can be individual, aimed at preserving single individuals with traits that ensure success in the struggle for existence within the population. It can also be group, fixing signs favorable for the group.

I. I. Shmalgauzen determined the forms of natural selection.

1. Stabilizing - aimed at maintaining the average rate of reaction of the trait against individuals with extreme, deviant traits. Selection operates under constant environmental conditions, is conservative, and is aimed at preserving the main features of the species unchanged.

2. Driving - leads to the consolidation of evading signs. Selection acts in changing environmental conditions, leads to a change in the average reaction rate, the evolution of the species.

3. Disruptive, tearing - aimed at maintaining individuals with extreme signs and the destruction of individuals with average signs. It acts in changing conditions, leads to a split in a single population and the formation of two new populations with opposite characteristics. Selection can lead to the emergence of new populations and species. For example, populations of wingless and winged forms of insects.

Any form of selection does not occur by chance, it acts through the preservation and accumulation of useful features. The selection is the more successful for the species, the greater the range of variability and the greater the diversity of genotypes.

Fitness - the relative expediency of the structure and functions of the body, which is the result of natural selection, eliminating unfit individuals. Traits result from mutations. If they increase the viability of the organism, its fecundity, allow to expand the area, then such characters are "caught up" by selection, are fixed in the offspring and become adaptations.

Types of fixtures.

The shape of the body of animals allows them to easily move in the appropriate environment, making organisms inconspicuous among objects. For example, the streamlined shape of the body of fish, the presence of long limbs in a grasshopper.

Camouflage - the acquisition of the resemblance of an organism to some object of the environment, for example, resemblance to a dry leaf or tree bark of a butterfly's wings. The body shape of the stick insect makes it invisible among the branches of plants. Needlefish are not visible among the algae. In plants, the shape of the flower: the position on the shoot promotes pollination.

Protective coloring hides the organism in the environment, making it invisible. For example, a hare has a white color, a grasshopper has a green one. Dissecting coloration - the alternation of light and dark stripes on the body creates the illusion of chiaroscuro, blurs the contours of the animal (zebras, tigers).

Warning coloration indicates the presence of toxic substances or special protective organs, the danger of the body to a predator (wasps, snakes, ladybugs).

Mimicry is the imitation of a less protected organism of one species to a more protected organism of another species (or environmental objects), which protects it from extermination (wasp flies, non-poisonous snakes).

Adaptive behavior in animals is a threatening posture that warns and scares off the enemy, freezing, caring for offspring, storing food, building a nest, burrows. The behavior of animals is aimed at protection and preservation from enemies and the harmful effects of environmental factors.

Plants have also developed adaptations: spines protect against eating; the bright color of the flowers attracts pollinating insects; different time of maturation of pollen and ovules prevents self-pollination; variety of fruits promotes seed dispersal.

All adaptations are relative in nature, as they operate under certain conditions to which the body is adapted. When conditions change, adaptations may not protect the organism from death, and, consequently, the signs cease to be adaptive. Narrow specialization can cause death in changing conditions.

The reason for the emergence of adaptations is that organisms that do not meet these conditions die and do not leave offspring. Organisms that survive in the struggle for existence have the opportunity to pass on their genotype and fix it in generations.

What is the relative nature of any adaptation of organisms to the environment?
= What is the relative nature of fitness?

Answer

When conditions change, fitness can become useless or harmful. For example, a white birch moth is clearly visible on a red wall.

The peacock butterfly has bright eye spots only on the upper side of the wings. Name the type of its coloration, explain the meaning of coloration, as well as the relative nature of fitness.

Answer

Color type - mimicry.
Color meaning: a predator can mistake the eye spots on the wings of a butterfly for the eyes of a large predator, get scared and hesitate, which will give the butterfly time to escape.
Relativity of fitness: bright colors make the butterfly visible to predators, the predator may not be afraid of the eye pattern on the butterfly's wings.

The wasp fly is similar in color and body shape to a wasp. Name the type of its protective device, explain its meaning and the relative nature of the device.

Answer

Type of protective device - mimicry.
Meaning: resemblance to a wasp scares off predators.
Relativity: being like a wasp does not guarantee survival, because there are young birds that have not yet developed a reflex, and specialized buzzards.

Name the type of protective device against enemies, explain its purpose and relative nature in a small seahorse fish - a rag-picker that lives at shallow depths among aquatic plants.

Answer

The type of protective device is camouflage.
The similarity of the seahorse with algae makes it invisible to predators.
Relativity: such a similarity does not give them a full guarantee of survival, since when the skate moves and in open space, it becomes noticeable to predators.

Name the type of adaptation, the value of protective coloration, as well as the relative nature of the fitness of the flounder, which lives in sea water near the bottom.

Answer

Type of coloration - patronizing (merging with the background of the seabed). Meaning: the fish is invisible against the background of the ground, this allows it to hide from enemies and from possible prey.
Relativity: Fitness does not help with fish movement, and it becomes visible to enemies.

In the industrial regions of England during the 19th-20th centuries, the number of birch moth moths with dark-colored wings increased compared to light-colored moths. Explain this phenomenon from the standpoint of evolutionary teaching and determine the form of selection.
=Explain the cause of industrial melanism in moth butterflies from the standpoint of evolutionary theory and determine the form of selection.

Answer

First, one of the butterflies developed a mutation that allowed it to take on a slightly darker color. Such butterflies are a little less noticeable on sooty trunks, therefore, a little less often than ordinary butterflies, they were destroyed by birds. They more often survived and gave offspring (natural selection took place), so the number of dark butterflies gradually increased.
Then one of the slightly darker butterflies had a mutation that allowed it to become even darker. Due to camouflage, such butterflies more often survived and gave birth, the number of dark butterflies increased.
Thus, due to the interaction of the driving factors of evolution (hereditary variability and natural selection), butterflies developed a dark masking color. Selection form: driving.

The body shape of the Kalimma butterfly resembles a leaf. How did a similar body shape form in a butterfly?
= Caterpillars of the turnip white butterfly have a light green color and are invisible against the background of cruciferous leaves. Explain, on the basis of evolutionary theory, the appearance of protective coloration in this insect.

Answer

First, one of the caterpillars developed a mutation that allowed it to acquire a partially green color. Such caterpillars are slightly less noticeable on green leaves, therefore, they were destroyed by birds a little less than ordinary caterpillars. They more often survived and gave birth (natural selection took place), so gradually the number of butterflies with green caterpillars increased.
Then one of the partially green caterpillars developed a mutation that allowed it to become even greener. Due to camouflage, such caterpillars survived more often than other caterpillars, turned into butterflies and gave birth, the number of butterflies with even greener caterpillars increased.
Thus, due to the interaction of the driving factors of evolution (hereditary variability and natural selection), the caterpillars developed a light green camouflage color.

Bee-like flies, which do not have a stinging apparatus, are similar in appearance to bees. Explain the emergence of mimicry in these insects on the basis of evolutionary theory.

Answer

First, one of the flies developed a mutation that allowed it to acquire a slight resemblance to a bee. Such flies were eaten a little less often by birds, more often survived and produced offspring (natural selection took place), so gradually the number of flies resembling bees increased.
Then one of these flies developed a mutation that allowed it to become even more like a bee. Such flies, due to mimicry, more often than other flies survived and gave birth, the number of flies with even greater resemblance to bees increased.
Thus, due to the interaction of the driving factors of evolution (hereditary variability and natural selection), mimicry under bees arose in flies.

On the body of a zebra that lives in the African savannas, dark and light stripes alternate. Name the type of its protective coloration, explain its significance, as well as the relative nature of fitness.

Answer

The zebra has a dissecting coloration. Firstly, such coloring hides the real contours of the animal from the predator (it is not clear where one zebra ends and another begins). Secondly, the stripes do not allow the predator to accurately determine the direction of movement and speed of the zebra. Relativity: against the backdrop of the savannah, brightly colored zebras are clearly visible.

The moth caterpillar lives on the branches of trees and at the moment of danger becomes like a twig. Name the type of its protective device, explain its meaning and relative nature.

Answer

Device type: camouflage. Meaning: A twig-like caterpillar is less visible and less likely to be eaten by birds. Relativity: on a tree of a different color or a pole, such a caterpillar will be clearly visible.

In the process of evolution, the white hare developed the ability to change the color of the coat. Explain how this adaptation to the environment was formed. What is its significance and how does the relative nature of fitness manifest itself?

Answer

Meaning: The hare has a white coat in winter and gray in summer in order to be less visible to predators.
Formation: mutations arose by chance, giving the hare this coat color; these mutations were preserved by natural selection, since hares that were invisible to predators survived more often.
Relativity: if a hare gets on a surface without snow in winter (rock, conflagration), then it is very clearly visible.

Name the type of protective coloration from enemies in females of open nesting birds. Explain its meaning and relative nature.

Answer

Type of coloring: masking (merge with the background).
Meaning: a bird sitting on a nest is invisible to a predator.
Relativity: when the background changes or the bird moves, it becomes noticeable.

The emergence of adaptability of organisms.
The main reason for the emergence of various adaptations of living organisms to the environment is selection. For example, it is known that the partridge is a forest bird. Depending on the habitat, it has various adaptations: a) shortening of the beak in connection with getting food from under the snow and leaf litter; b) the appearance of horn folds at the ends of the fingers to facilitate movement through the thick snow cover; c) expansion, rounding of the wings for quick rise into the air (the ancestors of the partridge did not have such a structure).
For further distribution, the fruits and seeds of plants also underwent various changes. These are hooks, thorns with which they are attached to animals, or light fluff that is dispersed by the wind.
The appearance of fitness in plants and animals is a characteristic phenomenon, but in any case, fitness does not appear immediately. As a result of a long evolutionary process, individuals with special features adapted to the conditions of the external environment appear.
Features of fitness in structure, color, body shape and behavior are clearly visible in the example of an aquatic mammal - a dolphin. The pointed shape of the body gives it the ability to easily and freely move in the water in different directions. The speed of the dolphin reaches 40 km / h. And in birds, indicators of fitness for flight are the presence of feathers covering the body; lack of auricles and teeth; the ability to turn the head 180 "; the lightness of the bones; the rapid digestion of food in the stomach, etc.
In many animals, fitness is so developed that it is difficult to distinguish them from the environment. The shape of the body, the color of fish, animals living in dense thickets of algae, help them successfully hide from enemies.

Adaptation types:

1. Protective (masking) coloring and its types.
2. Instinctive adaptation.
3. Caring for offspring.
4. Physiological adaptation.

Rice. 21. Adaptability of night butterflies by changing the color to the corresponding colors of the tree trunk: 1 - the same number of marked dark and light butterflies; 2 - light tree trunk; 3 - increase in the number of light butterflies; 4 - increase in the number of dark butterflies; 5 - dark tree trunk

1. Protective (masking) color and its types. Protective coloration - the adaptability of organisms that live openly and can be accessible to enemies. Birds that incubate their eggs on the ground (grouse, partridge, quail, etc.) merge with the surrounding background. A bird sitting motionless on the nest is almost invisible to its enemies. The eggs with pigmented shells and the chicks hatching from them are also hardly noticeable. In large predators whose eggs are inaccessible to enemies, or in birds that lay eggs high on rocks or bury them. into the ground, the protective color of the shell does not develop. Butterfly caterpillars are usually green, the color of the leaves, or dark, the color of the bark. Bottom fish (stingray, flounder) are often painted in the color of sand.
Desert animals are usually sandy-yellow in color. Monochromatic protective coloration is characteristic of insects (locust), lizards, saigas, lions. Many animals change color depending on the season. For example, arctic fox, white hare, partridge are white in winter. Diurnal butterflies have a protective coloration on the lower part of the wings, while night butterflies have a protective color on the upper part of the wings, so during the day they become visible to enemies and may die (the lower part of the wings is light). Protective coloration can also be observed in the form of insects: the chrysalis of butterflies on a branch is very similar to a kidney; a larva attached to a branch in a motionless state, similar to a tree branch, etc.
Protective coloration is especially useful at the initial stages of the individual development of the organism (eggs, larva, nestling). Protective coloring is needed for slow moving animals or those that have passed into a state of rest.
Many animals are able to quickly change color depending on the color of the environment, and this ability is inherited. For example: chameleon, flounder, agama.

Types of protective coloring:

1. protective coloring;
2. attractive coloring;
3. menacing coloration;
4. imitative coloration.

1. Protective warning paint characteristic of poisonous, stinging or burning insects. For example, a ladybug (red, yellow, brown, dark red, striped) is never pecked by birds because of the release of a poisonous, bitter yellowish liquid (Fig. 22). If the chicks accidentally peck at this beetle, then the next time they do not approach it. The scavenger beetle emits an unpleasant burning liquid, has a bright red striped color. The coloring of bees, bumblebees, wasps, poisonous snakes protects them from predators. Protective coloration also depends on the behavior of some insects and animals. Sometimes crawling beetles freeze in moments of danger. Bittern, nesting in the reeds, accidentally seeing the enemy, stretches its neck, raises its head and freezes. Warning coloration in animals is combined with behavior that repels predators.

Rice. 22. Warning coloring: 1 - ladybug; 2 - blister

2. Attractive coloring. This coloration is especially important during breeding. The bright color of red butterflies, blue-winged grasshoppers, jerboas, plumage of male birds attracts females during the breeding season. On ordinary days, the coloring merges with the environment and becomes invisible to enemies (Fig. 23).

Rice. 23. Attractive coloring: 1 - red sash; 2 - blue-winged filly; 3 - jerboa

3. Menacing coloration. In times of danger, animals take a threatening posture. For example, in moments of danger, a cobra raises its head straight, puffs out its neck and assumes a threatening posture; the darkling beetle raises its abdomen and emits an unpleasant odor. The eared roundhead instantly opens the skin folds on the head and freezes with its mouth open. On the open wings of the praying mantis there are spots that look like eyes. In case of danger, opening its wings, the praying mantis scares away its enemy. The same spots are also found in night butterflies (Fig. 24).

Rice. 24. Threatening coloration: eye spots on the wings of a butterfly (1) in a threat pose look like the eyes of an elf owl (2)

4. Imitative coloring -mimicry(Greek mimikos - "imitation"). This is the imitation of animals and plants of living organisms or certain inanimate objects of the environment. The warning coloration of unprotected organisms bears a resemblance to one or more species. For example, in terms of body shape, size, bright color, a cockroach is similar to a ladybug. The body shape of a seahorse and a fish-walker resembles an algae. A white butterfly with an unpleasant odor and bright color imitates inedible butterflies from the heliconid family (Fig. 25), and flies imitate wasps. The similarity of non-venomous snakes with poisonous ones helps them to protect themselves from enemies and survive.

Rice. 25. Imitative coloration: white butterfly (T) looks like a poisonous heliconid butterfly (2)

Examples of imitative plant coloration.
Imitative coloration in plants is necessary to attract or intimidate animals. Usually there is no nectar on the Belozor flower. To attract insects, it is similar to a honey plant. Insects, sitting on a flower, contribute to its pollination. The flowers of the insectivorous plant (nepenthes) are brightly colored. Insects, sitting on a flower, instantly fall into the "trap" and die. The orchid resembles the female of some insects in the shape of the flower and smell, so male insects involuntarily sit on the flower and pollinate it.
Mimicry occurs under the control of natural selection. Its occurrence is associated with the accumulation of small beneficial mutations in edible species in the conditions of their coexistence with inedible ones. One of the main weapons of defense against enemies and adaptive features is: for bugs and crabs - a chitinous cover, for mollusks - shells, for crocodiles - scales, for armadillos and turtles - a shell, for a hedgehog and porcupine - needles.

Fitness. Protective coloration. Protective coloring. Attractive coloring. Threatening coloration. Imitative coloration (mimicry).

1. The main reason for the various adaptations of organisms to environmental conditions is selection.
2. Protective coloration is an adaptability necessary to protect organisms that lead an open lifestyle from enemies.
3. Protective coloration - a type of protective coloration characteristic of poisonous, stinging, burning insects.
4. Attractive coloration - a type of protective coloration during the reproduction period of organisms.
5. Menacing coloring is a way of protecting animals from enemies by adopting a threatening posture.
6. Imitation of living organisms and inanimate objects of the environment is the adaptability of organisms that are not able to defend themselves or are inactive.
7. What characteristics of organisms determine fitness?
8. How does fitness come about?
9. Name the types of protective coloration.
10. Give an example of protective coloration.
1. What organisms are characterized by imitative color?
2. Give examples that prove the usefulness of eye-catching coloring.
3. What are examples of mimic color in plants?

Exercise
Have you met insects in nature that freeze when touched? Pay attention to their actions, immobility. Pay attention to insects that emit an unpleasant odor. Compare them. This task will help you become more familiar with the protective and threatening coloration of animals.
Try to complete the task.
To what type do the given examples of protective coloration belong? Enter in capital letters accordingly: "ZShch" - protective; "PR" - attracting; "PD" - imitative.

1. Ladybug. 5. Nepenthes (insectivorous plant).
2. Butterfly. 6. Bittern.
3. Black beetle. 7. Male pheasant.
4. Sea Horse. 8. Mantis.