Question: why have various forms of care for offspring been preserved, if all of them are not as effective as possible? Caring for offspring in animals Caring for offspring until they become independent.

Why are various forms of care for offspring preserved, if all of them are not as effective as possible?

Answers:

That's how nature works. These behaviors are mainly regulated by hormones secreted by the pituitary and ovaries. In order for a species to continue to exist, each generation must leave behind offspring capable of reproduction. Most invertebrates and fish do not care for their offspring. They simply lay thousands of eggs, only a part of them hatch into young, and an even smaller number grow and multiply. A more reliable way to continue the race is to provide them with food, protection from predators, and even teach some skills after the birth of a limited number of cubs. Caring for offspring is shown in various forms by many animals. Most of them are endowed with special parental instincts, but in highly organized animals importance also has individual experience.

Similar questions

• A cyclist traveled at a constant speed from city A to city B, the distance between which is 100 km. After resting, he went back to A, increasing his speed by 15 mph. On the way, he made a stop for 6 hours, as a result of which he spent as much time on the way back as on the way from A to B. Find the speed of the cyclist on the path A to B. Please help(

Theme of the lesson "Care for offspring"

During the classes:

I. Organization of the beginning of the lesson.

I I . Introduction to the topic of the lesson:

1. Frontal conversation:

- What is fitness?

What forms of adaptation do you know? Name them and give examples

How to understand what fitness is wearing relative nature?

2. Biological dictation.

Insert the term that this definition means.

1. The process of survival of the most adapted individuals in given conditions is called ...

2. Coloration to help hide in environment, is called ...

2. The acquisition of similarity with some object is called ...

3. The similarity between unprotected and protected species is called ...

4. Any ... is relative.

Answer: natural selection protective coloration, disguise, mimicry, fitness.

III . Formation of new knowledge:

We have identified: morphological, physiological, biochemical, ethological adaptations. Ethological adaptations are possessed by animals with a highly developed nervous system. Such adaptations are manifested in various forms of animal behavior aimed at the survival of individual individuals and the species as a whole. Distinguish between congenital and acquired ethological adaptations, congenital include mating behavior, care for offspring, avoidance of predators, migration. Today we will focus on caring for offspring.

How does it manifest itself in representatives of various classes of animals and what does it serve?

1 slide. Caring for offspring is a chain of successive reflexes developed in the process of evolution that ensure the preservation of the species.

How is care for offspring manifested in different animals?

3 slide. Class Insects . In those species of insects that take care of their offspring, it is expressed in the fact that the parents seek to provide their offspring with a source of food. A striking example of this is the scarab beetle. From fresh manure they make balls and roll back some distance. Here they burrow into the ground, and are either eaten by the beetles themselves or an egg is laid on it. The larva that emerged from it is provided with tasty food for the entire period of its development. We see such a phenomenon in cabbage butterflies, wasps, moths, riders.

4 slide. Class Arachnids. Female karakurt, deadly poisonous spider living in Central Asia turns out to be quite a caring mother. Eggs placed in an egg cocoon are suspended from the ceiling of the cave in which the spider lives. They are under reliable protection, first of the mother's poison, and then, when she dies, they hibernate under a dense shell.

5 slide. Crustacean class. crayfish do not abandon their offspring either. They carry eggs with them. When rachata hatch from eggs, they attach to the mother's abdominal legs. And there they remain until they become independent.

2. Class Fish.

6 slide. For many millions of years, fish have developed amazing ways of caring for their offspring. Rybka tilapia carries eggs and fry in its mouth! The fry calmly swim around their mother, swallow something, wait. But as soon as the slightest danger arises, the mother gives a signal, sharply moving her tail and trembling in a special way with her fins, and ... the fry immediately rush to the shelter - the mother's mouth.

7 slide. On a freshwater fishbitterness during reproduction, the ovipositor grows. The female lays eggs in the mantle cavity of bivalves. This is where the fry of the mustard develop. Some fish build nests for fry. Nests are built from foam by macropods, gourami, labyrinth fish.

8 slide . The male three-spined stickleback also builds a nest for the female. When the nest is ready, the male drives the females there one by one, who lay several eggs there. The females swim away and the male guards the nest. It also refreshes the water by quickly moving the pectoral fins.

9 slide. Bottom fish lumpfish found in the Barents and White Seas. At low tide, when the eggs are aground, the lumpfish draws water into the stomach, splashes the eggs from the mouth.

10 slide . At seahorses the male takes care of the offspring. The female lays eggs for him in the pouch under the tail, where he bears it. Even after the fry have hatched, the male carries them in a bag for some time.

3.Class amphibians .

11 slide. Most egg-laying amphibians do not exhibit any parenting behavior, and after spawning leaves water bodies, leaving their offspring to fend for themselves. However, for example, the bullfrog inhabiting the islands of the Caribbean has been guarding the eggs and the larvae that have hatched from them for a long time. Moreover, the male monitors the water level in the drying puddles in which they develop, and, if necessary, deepens the puddles or digs a groove into the neighboring puddle, along which he then drives the tadpoles into it. tree frogs. Dwelling in crowns rainforest, many tree frogs face the problem of finding water for their offspring. Therefore, among the representatives of this family there are those who have developed very interesting forms of caring for their offspring. In some species, parents build special nests on plants that replace reservoirs for larvae, in others they build artificial reservoirs, in others they hatch eggs and larvae on themselves.

12 slide. Thus, tropical leaf frogs lay their eggs on the leaves of trees and guard the masonry until the larvae hatch. The tadpoles hatched from the eggs crawl onto the wet back of the male, and he transfers them one by one to micro-reservoirs located right there on the trees, in the axils of the leaves. In the absence of suitable reservoirs, tadpoles remain on the back of the male during the entire period of metamorphosis. He periodically bathes with them in larger puddles. In some leaf climbers, males constantly transfer tadpoles from one bath to another so that they, having eaten all the food in a small pond, do not starve. In one species of leaf climbers, the female carries the tadpoles into the reservoirs located at the base of the leaves. Then she regularly visits the cubs and lays several unfertilized eggs in the water, which serve as food for the tadpoles.

13 slide . Very caring fathers are males of the European land midwife toad. Females lay their eggs on land in the form of two cords containing 20-50 eggs each. The male helps the female to get rid of them. Grasping the cords with the toes of his hind legs, he pulls them out and wraps them around himself. An active male can get eggs from two or three females in this way. During the entire period of caviar development, the male wears cords on himself. At the end of this period, the male goes in search of a reservoir, where the larvae hatch. After that, he is freed from the empty cords. Some species of frogs hatch eggs and larvae in special brood bags. During the breeding season, the skin that forms the bag changes its structure. Poisonous glands, pigment cells disappear from it, keratin is absorbed. It becomes tender and enriched with vessels. For the whole White light the pipa toad became famous: it bears eggs on its back! In special cells, similar to honeycombs. Such a living baby stroller with 200 seats! He carries tadpoles on himself until they stand on their feet.

14 slide. In Australian marsupial tree frogs, pouches-pockets are located in the cloacal region of males. The development of eggs takes place on the ground, and the larvae that emerge from it themselves crawl into the bags of their parent. A large yolk sac provides them with sufficient nutrition and allows them to stay in brood sacs until metamorphosis. In a number of species, the bag, like a backpack, is located on the back or on the stomach.

4. Reptiles .

Only a few reptiles guard their clutches, and almost none of them care about the fate of the cubs that are born.

15 slide . Moreover, many reptile mothers, on occasion, can eat their own offspring. The exception is crocodiles. They lay their eggs in peculiar nests made of sand, clay and stones. carefully guard the "nest". And after hatching, the cubs are very carefully transferred to a safer place.

16 slide. sea ​​turtles make long-distance migrations for the purpose of breeding on certain parts of the sea coasts. They gather in these places from different regions, often located many hundreds of kilometers away. For example, a green turtle, heading from the coast of Brazil to Ascension Island in Atlantic Ocean, overcomes a distance of 2600 km, fighting currents and maintaining an accurate course. On land, the female moves with great difficulty, clumsily pushing her body forward and leaving behind a wide track, similar to the track of a caterpillar tractor. She moves slowly and strives for one single goal - to find a suitable place for masonry. Having got out of the surf line, the female carefully sniffs the sand, then rakes it and makes a shallow hole, in which she then digs a jug-shaped nest with the help of only her hind limbs. The shape of the nest is the same in all species of turtles. During the breeding season, females lay eggs two to five times; in laying from 30 to 200 eggs. There is no parental behavior in turtles; after laying eggs, they go back to the sea, and, having hatched, the cubs make their way from the shore to the waterand further without parents

5. Bird class.

It rarely happens that an incubating bird, or especially a bird at the brood, tries to hide unnoticed at the moment of danger. Large birds, protecting their brood, attack the enemy. At the same time, a swan can break a person’s arm with a blow of a wing. More often, however, the birds "take away" the enemy. At first glance, it seems that the bird, saving the brood, deliberately distracts the attention of the enemy and pretends to be lame or shot. But in fact, the bird at this moment has two opposite aspirations-reflexes: the desire to run and the desire to pounce on the enemy. The combination of these aspirations creates complex behavior a bird that appears conscious to the observer. When the chicks have hatched from the eggs, the parents begin to feed them. During this period, there is a strict division of labor.

17 slide. In black grouse, capercaillie and ducks, only one female leads the brood. The male does not care about the offspring. Only the female incubates at the white partridge, but both parents walk with the brood and “take away” the enemy from it. However, in brood birds, parents only protect the chicks and teach them to find food. The situation is more complicated in chicks. As a rule, both parents feed them, but often one feeds vigorously, while the other is lazier. In the great spotted woodpecker, the female usually brings food every 5 minutes and manages to feed the chicks three times until the male arrives with food. And in the black woodpecker, the chicks are fed mainly by the male.

18 slide. In the sparrowhawk, only the male hunts. He brings prey to the female, who is inseparably at the nest. The female tears the prey into pieces and gives them to the chicks. If the female died for some reason, the male will put the brought prey on the edge of the nest, and in the meantime the chicks will die of starvation. Small birds feed chicks very often. The great tit brings food to the chicks 350-390 times a day, the nuthatch - 380 times, the demoiselle swallow - up to 500 times, and the American wren - even 600 times. The swift sometimes flies as far as 40 km from the nest in search of food. He brings to the nest; not every midge caught, but a mouthful of food. He glues the prey with saliva into a ball, and having flown to the nest, he deeply sticks balls of insects into the throats of the chicks. In the first days, the swifts feed the chicks in such enhanced portions 34 times a day, and when the chicks grow up and are ready to fly out of the nest, only 4-6 times. But even after flying out of the nest, the chicks still need parental care for a long time. Only gradually do they learn to find and peck prey themselves.

6. Mammals.

19 slide. Mammalian care for offspring can take many forms. The female echidna bears the laid egg in the bag formed on the belly. The platypus incubates 1-2 eggs in a hole where it arranges a nest for this.

20 slide. The female kangaroo carries her cub for 8 months in a bag on her stomach. The young kangaroo, who has grown up and has already begun to feed on his own, uses it as a temporary shelter for a long time. At the Florida Aquarium, a female bottlenose dolphin was observed supporting her newborn in a floating position on the surface during his first breaths. It is interesting that other females who were right there also helped her in this.

21 slide . A case is known when a chimpanzee mother until then shook, tossed and shook her newborn, who did not show any signs of life, until he began to move and breathe. Monkeys use such "educational" techniques in relation to naughty cubs as spanking, biting, pushing, pulling the hand, etc. Monkeys often support or help cubs when climbing, form with their bodies a "bridge" along which the cubs are transported from tree to tree etc.

22 slide Improvement of the nest, keeping it clean, guarding the brood are also a vivid expression of parental instincts. So, for example, a female rabbit insulates the nest with fluff plucked from her belly, other animals arrange a litter of soft plant materials. Mother eating dead fetuses, feces of cubs, transferring them from a contaminated shelter to another, changing bedding - all this is of great hygienic importance and to some extent helps to hide the location of the brood from enemies, as they eliminate the smell of the lair. The mother often licks the fur of the cubs, looking for fleas from them. Female raccoon dogs and badgers often take small puppies out of their burrows "into the air" and after a while carefully return them to the nest again. Temporarily moving away from the den or nest, the parents cover the cubs with bedding material or clog the burrow inlet. Returning to the litter, the parents usually linger at a distance for some time, go around the den, checking the absence of danger, such as a wolf or a fox. During the breeding season, mature wolves, as a rule, do not attack livestock grazing near the den; if this "rule" is violated, then usually not by adult animals, but by over-flyers that lingered not far from the lair. Parents "punish" disobedient cubs, bringing them into obedience. Observing, for example, a fox brood at a hole, one can become a witness of how one of the parents, grabbing a cub that lingered on the surface after an alarm signal, shakes it vigorously several times and drags it into the hole.

7.Man. 23 slide. Care for offspring reaches its highest development in a cultured person, doomed from the time of birth to prolonged helplessness and requiring prolonged preparation for the social conditions of life. While mammals feed their children until they are able to feed themselves, which usually happens after a few weeks and at most a few months or two or three years after birth, in man the concern for offspring extends to the onset of a period which makes it possible for the cultural classes to independently earn their living, and for the cultural classes - until the onset of full mental capacity for work, on which, in fact, the formation of a family is based, which has as its main goal the upbringing of children.

Many examples can be given that people are excellent parents and an example for children. But nowadays often human society there are cases of abandonment of their parental responsibilities, cruelty and violence against children, which is rarely seen in animals.

24 slide. It can be divided into three groups

Caring for offspring

Passive Active Preventive

Guys, give your examples of these groups:

IV Summing up the lesson.

Caring for offspring is …….

The evolutionary meaning of caring for offspring…….

Active care of offspring is …….

Passive care of offspring is ……..

Preventive care for offspring is ......

V Lesson grades.

VI D/Z messages. pp. 45-49 read and answer the question "Why are various forms of offspring preserved, if not all of them are as effective as possible?".

We are all accustomed to seeing a mother with a stroller, or with a child in her arms. In each country, children are carried differently: in their hands, in a special backpack - “kangaroo”, in a cradle, just in fabric over their shoulders, or on their chest - “sling”, on their shoulders (typical for their father). How do animals carry their babies? wild nature?
Animals after birth necessarily have a certain need to transfer their still completely helpless offspring somewhere. Monkeys, for example, have a sufficiently developed grasping reflex, so from birth they cling to their mother's hair with their hands, hanging down securely. At the same time, the mother can safely climb, and even jump on trees, without causing trouble to the baby. During this time, kids have time to learn all the intricacies of getting food, getting rid of enemies, assimilating the social laws of life. Opossums have surpassed the monkeys even more, they have not one, but several cubs that stick around the mother from all sides, holding on to the wool, and she does not lose anyone.
About Australian kangaroos everyone knows, they are nurtured in a special bag, where a miniature cub the size of a large bean grows to normal size. At first, the baby hangs on the nipple, sucking tightly, eventually begins to look out of the bag, and later jumps out. That is, kangaroos up to two years old can be in the mother's "pocket", and there are times when there can be 1-2 in the bag. summer child and on the nipple to hang a newly born baby.
Little hippos calmly "ride" in the water on the back of their mother. Elephants, although quite rare, raise their children on tusks and carry them to another place.
Mice, shrews save their numerous offspring by placing them in the form of a “train”: one baby grabs the mother’s hair above the tail with his teeth, the second takes the third one, the next one and so on until the last. So the whole family moves together. Rats are even better adapted to changes in their place of residence: if the rats are more or less adults, they follow each other, holding on to their tails, but if the children are very tiny, they transport them on their tail, stringing them like beads.
Crocodiles, having waited for the hatching of their offspring, which gives a voice from the sand, help them get out, tear the sand and carry it into the water in their terrible mouth, almost between the teeth. And not a single baby suffers from this. Some amphibians can also carry eggs, tadpoles, and small frogs on their backs.
Interesting stories naturalists report about turtles: the offspring of crocodiles and turtles are bred under the same conditions, their eggs are laid in the sand, and the babies hatch in the same way. Therefore, crocodiles can carry turtles along with their babies, while suppressing their cruelty and aggression, that is, in this situation, the maternal instinct dominates.
Transportation in the teeth is the most common mode in many animals. Watching the animals, you can clearly see that they take the kids exactly by the withers, which is enough vulnerable spot. Parents can firmly clench the skin with their teeth, but they never cause harm, injury, or mutilation. Looking closely at pets - cats and dogs - this can often be seen. Cats are generally excellent mothers. They feed their kittens long enough breast milk until the baby grows up and can eat more adult food on its own. In order for the kitten to receive enough vitamin and energy, it is necessary to choose high-quality food. The best option royal canin cat food, and your kitten will always be energetic, cheerful and healthy.
The mother-medicine does not indulge her baby with transfers, more often the bear cub runs after adults, turns over in a ball, overcoming obstacles, but when there is a real danger or obstacle, the mother takes him in her teeth and takes him to a safe place. There are times when even a hedgehog in its teeth takes babies to a dry place if their hole is flooded with water.
Wolves, sensing danger, quickly, with feverish speed, carry their puppies in their teeth into a spare hole. But in the course of evolution, another thought has developed about wolves: hunters report that the she-wolf will not even give a voice, and not that she will rush at people who take her cubs into a bag. They are too afraid of humans.
Ungulates travel with children over long distances, holding them between their bodies, feeling their sides next to them. Moose become too aggressive when people approach them at a time when the baby is still on fairly thin, unstable legs, is nearby. In elephants, although the children look big, they are completely useless, even their personal trunk interferes with them, so it is safer to be on the side of the mother. Often the baby hides under the belly of adult elephants, and they support them with their strong trunks if necessary.
They write about the interesting relatives of our pigs - warthogs that they bring up in their babies the ability to twist from birth: having large fangs, in a tight hole, the mother never cares not to injure her children with them, they themselves must be able to dodge danger, therefore those who survived will be able to live on. According to statistics in the wild, the mortality of offspring is quite high. But, having learned the tricks of survival from childhood, the animal has a chance to live as long as it is given.
Some birds can carry not only chicks, but also eggs in their beaks. Some carry under the wings. Waterfowl “roll” babies on their backs, as they are ready for life immediately after hatching: they dried up and set off. A strange sight can be seen as ducklings run after a duck right across the water, although they have very little strength. But when fatigue sets in, they climb onto their backs and hide in their mother's feathers. The same can be observed in swans. On the mother's back, they not only rest and warm themselves, but also feel safe. Not every predator wants to get to the birds floating in the middle of the pond with chicks on their backs. On land, swans can also fight back, the wing beats are strong enough and can even kill a fox.
Incredibly, some birds carry their babies in their paws. For example, a forest sandpiper does it in this way. In case of danger, he grabs the chicks in his paws and flies away from her, even making zigzag movements in flight. And the black grouse, capercaillie, with the necessary signal, force the chicks to hide, or move imperceptibly towards the mother.
Scientists believe that a chick that has fallen out of the nest is of little concern to its parents. Seeing herons is proof. When a heron chick, staggering in a nest above the water, suddenly falls, the mother does not pick it up, although having a long beak it is quite easy to do this, apparently they think that "what has fallen is gone." But ornithologists think differently: this is natural selection, if there is no tenacity, then it is not entirely viable.
Unlike herons, almost all birds and other animals, risking their lives, try to save their offspring at any cost: they distract them from predators, make several nests, one of which is false, pretend to be sick and wounded, grab them in the teeth, make a terrible noise and din . After all, caring for offspring is one of the main concerns in life.
Of course, for some groups of organisms, care for offspring does not exist. Firstly, in fish, since the amount of reproductive material in them is quite large, and their genus has flourished for millions of years. Although some of them can be found guardianship:
- in salmon, which lays eggs in favorable conditions, migrating to spawning sites over considerable distances, after which it dies, fertilizing the environment for fry;
- stickleback fish spawns little, about 50-70 pieces, making a plant nest at the bottom of the reservoir, and after the appearance of babies, it protects it from enemies;
- the seahorse hides its fry in a bag on its stomach.
So, in the multifaceted animal world, a mother is ready to risk and sacrifice her life for the sake of her offspring. This is the most important law of nature.

In order for a species to continue to exist, each generation must leave behind offspring capable of reproduction. Most invertebrates and fish do not care for their offspring. They simply lay thousands of eggs, only a part of them hatch into young, and an even smaller number grow and multiply. A more reliable way to continue the race is to provide them with food, protection from predators, and even teach some skills after the birth of a limited number of cubs. Caring for offspring is shown in various forms by many animals. Most of them are endowed with special parental instincts, but in highly organized animals, individually acquired experience is also important.

In its simplest form, care for offspring is present in all organisms and is expressed in the fact that reproduction occurs only under conditions favorable for offspring - in the presence of food, a suitable temperature, etc.

Caring for offspring in many animals begins with preparation for its birth. Often seasonal migrations animals are associated with movement to breeding areas, sometimes many thousands of kilometers away from their habitats. Animals that do not make such long journeys also choose their nesting territory in advance, and many of them carefully guard it and prepare shelters - nests, burrows, dens adapted for future offspring.

Many parental concerns are related to the rearing of offspring.

In most insects, care for offspring is simple. It is enough for the female to lay her eggs in a place where her larvae would find suitable food, for example, cabbage white butterfly larvae - cabbage. But some insects specially prepare shelter and food for their offspring, for example, honey-gatherers - wasps and bees. And the hunter wasps supply their larvae with crickets and grasshoppers. Before laying an egg, the sphex wasp injects poison into the nerve ganglions of its victim, so that it remains motionless, but alive and serves as a fresh food supply for the larva for the entire period of its development. In dung beetles, not only females, but also males participate in the preparation of food for offspring - dung balls.

In many birds, the chicks hatch completely helpless and need frequent and regular feeding, some insectivorous birds feed their offspring up to 200 times a day! Sometimes parents (jays, nutcrackers, etc.) store food for future chicks from autumn. The offspring of brood birds - chickens, ducks, geese, etc. - are born independent, able to swim, walk, peck. Parents can only lead them to food, water, protect them from enemies, warm them (see Imprinting).

Mammal females feed their young with milk until they are able to eat other foods. In some animals, this period lasts several weeks, in others it is longer, and in great apes- some years. Gradually, parents begin to accustom children to adult food - show edible plants, learn to hunt.

Many animals protect offspring from enemies. In birds, colonial nesting serves this purpose, but solitary nesting birds can also unite to drive predators away from their nests. For example, if a cat or even a person tries to climb a tree where there is a crow's nest, 10-15 birds flock to it, screaming at the disturber of the peace.

Most mammals are more excitable than usual during the parenting period. Many large wild mammals attack people precisely when they threaten the cubs or are close to them. The moose does not allow anyone to the cub, including other moose.

In many mammals and birds, cubs stay with their parents for a long time, acquiring the skills necessary for life by imitation. This is the period of raising offspring. Parents teach cubs to choose and find food, water, and even medicinal plants, as well as shelters for sleeping or in case of bad weather. These forms of parental care are especially developed in mammals with long term life. In elephants and some great apes, adolescence lasts up to 8-10 years. Not only parents, but also almost all adult members of the group take part in the upbringing of their offspring. Older brothers, and especially sisters or just females who do not have this moment their own offspring, they watch the cub, help feed it, care for it, play with it. In the event of the death of the mother, they, as a rule, adopt the orphaned cub. Such a collective form of care for offspring greatly increases the chances of its survival.

The highest development of care for offspring is received by a person. He not only takes care of the life support of children, but also educates them, gives them his life experience and knowledge accumulated in history.

The value of caring for offspring

Of great importance, especially in immature animals, is parental care for offspring, that is, the actions of animals that ensure or improve the conditions for the survival and development of offspring. In the process of evolution, many groups of animals developed adaptations for the protection and nutrition of developing offspring on the part of the parent. This includes the passage of the embryonic stages of development in the body of the mother. However, the concept of "caring for offspring" applies only to the postembryonic period. In some cases, care for offspring is limited to creating a shelter and preparing food for future offspring, but the mother does not meet with him (preventive care for offspring). So, some wasps lay their eggs on insects paralyzed by them, which are hidden in specially dug minks, but then they no longer care about the hatched larvae.

More high form care for offspring is the care of offspring, manifested in two main forms: passive and active. In the first case, adults carry eggs or young animals with them in special skin recesses, folds, bags. At the same time, young animals sometimes feed on the secretions of the mother. This form of care for offspring is found in certain types echinoderms, crustaceans, mollusks, spiders, fish (seahorse and needle, some tropical perciformes - cichlids), amphibians (midwife toad, American pipa, gastrotueca marsupiata frog), lower mammals (echidna, marsupials). With active care for offspring, adults perform specific actions aimed at providing for all or many areas of its life - insect larvae, juvenile fish, chicks, and young mammals. In addition to arranging shelters, feeding, heating, protecting, cleaning the surface of the body, etc., parents in many higher animals (birds and mammals) also teach their offspring (for example, to find food, recognize enemies, etc.).

It is the active care of the offspring, the highly developed care for it that makes immature birth possible, and thus all the features caused by it. mental development. At the same time, the evolution of care for the offspring was marked, on the one hand, by the intensification and differentiation of the actions of parents in relation to the offspring, on the other hand, by the strengthening of its dependence on adult animals. At the same time, fertility dropped sharply. However, the growing concern for offspring entails a growing contradiction between the needs of the parent and its offspring. This contradiction is regulated natural selection towards the greatest progress of the species. V. A. Wagner characterized this with the formula: the minimum of mother's sacrifices - the maximum demands of offspring.

Thus, the progressive evolutionary acquisitions, which ensured a more flexible adaptation of the growing organism to the conditions of its life in postnatal ontogenesis, are of a very complex nature and include different forms caring for offspring, depending on the degree of maturity. The whole complex of these factors determines in each case the specific course of the postnatal development of behavior.