Common features of humans and mammals. Common signs of man and mammals The position of man in the system of the animal kingdom

Biology lesson. Grade 9

Topic : The place of man in the system of the organic world. Man as a species, his similarities with animals and his difference from them.

Goals and objectives of the lesson:

1. To acquaint students with the main groups of evidence for the origin of man from animals that modern biological science has.

2. To form the ability to compare humans with other mammals and draw conclusions based on this comparison.

3. Convince students that the origin of man could be related to the evolution of ancient great apes.

Equipment :

1. Interactive tutorial "Evolutionary teaching".

2. Models of human predecessors.

3. Handout.

Lesson Plan :

1. The origin of man, the history of the issue.

2. The systematic position of a person.

3. Evidence of the origin of man from animals.

4. Human evolution.

5. Consolidation of knowledge on the topic.

During the classes .

What is the origin of man, how did he appear on Earth? There are many opinions about this. (Students express known versions of the origin of man). The accumulation of scientific data, especially in recent years, when the genomes of humans and many other organisms were deciphered, made it possible to construct and substantiate the theory of the origin of man from animals. Today we will look at the evidence for the origin of man from animals that underlies this theory.

In his system of the animal world, K. Linnaeus placed man in the group of primates, along with semi-monkeys and monkeys. J.B. Lamarck was the first to write that man descended from ape-like ancestors who switched from climbing trees to walking on the ground. The new way of locomotion led to a straightening of the body, freeing the arms and changing the foot. The herd way of life contributed to the development of speech.

In the books “The Origin of Man and Sexual Selection”, “On the Expression of Emotions in Man and Animals”, Charles Darwin comes to the conclusion that man is an integral part of wildlife and that his appearance is not an exception to the general laws of development of the organic world. Having extended the main provisions of the evolutionary theory to man, Ch. Darwin introduced the problem of the origin of man into the mainstream of natural science research. First of all, he proved the origin of man "from a lower animal form." In the book “The Origin of Man (1871), Charles Darwin convincingly proved that man represents the last, highly organized link in the chain of development of living beings and has common distant ancestors with anthropoid apes. Thus, man was included in the general chain of evolutionary changes in living nature that took place on Earth for hundreds of millions of years. However, Charles Darwin did not limit himself to this. On the basis of comparative anatomical, embryological data pointing to the great similarity between man and great apes, he substantiated the idea of ​​their relationship, and, consequently, the commonality of their origin from the ancient original ancestor. Thus was born the "monkey" theory of anthropogenesis.

According to this theory, man and modern apes descended from a common ancestor who lived in the Neogene era and, according to Charles Darwin, is a fossil ape-like creature. The German scientist E. Haeckel called the missing transitional form Pithecanthropus. In 1891, the Dutch anthropologist E. Dubois discovered parts of the skeleton of a humanoid creature on the island of Java, which he called Pithecanthropus erectus. Over the past century, outstanding discoveries have been made, as a result of which numerous bone remains of fossil creatures have been discovered - intermediate between the ape ancestor and modern man. Thus, the validity of Ch. Darwin's simial theory of anthropogenesis was confirmed by direct evidence.

The main groups of evidence for the origin of man from animals:

1. Paleontological.

2. Embryological.

Having left the animal kingdom, Homo sapiens remains one of its members, although he is in a special position (entry in notebooks):

Such is our position in the system of the organic world.

Man is a representative of the class of mammals, he is a vertebrate animal and therefore is related to fish, amphibians, reptiles and birds.

Working with handouts.

Work with the interactive tutorial "Evolutionary Teaching".

The similarity of many anatomical and physiological features testifies to the relationship of great apes and humans. This was first established by Charles Darwin's colleague - T. Huxley. Having carried out comparative anatomical studies, he proved that the anatomical differences between humans and higher apes are less significant than between higher and lower apes.

Let us recall the concepts of "rudiments" and "atavisms" (entry in notebooks).

Rudiments - these are organs that once actively functioned among our ancestors, but now have lost their significance.

atavisms - These are signs characteristic of animals and that have appeared in humans.

Similarities between humans and animals(notebook entry).

(man descended from a common ancestor with apes)

1. General plan of the structure of organ systems, skeletal departments;

2. Similarity of embryos;

3. The presence of rudiments (coccyx, appendix, third eyelid);

4. The presence of atavisms (multiple nipples, hairiness, the appearance of a tail);

5. Composition of the blood;

6. Chromosome set in a cell (human - 46, chimpanzee - 48)

7. The presence of nails on the fingers;

However, there are also significant differences between humans and great apes, largely due to the adaptability of humans to walking upright.

The difference between man and animals(notebook entry).

1. Vertical position of the body;

2. The ability to move on two limbs;

3. The forelimbs are adapted for grasping;

4. Large brain volume;

5. Double arching of the foot;

6. The ability to make and use tools.

The body of a reasonable person is built from the same basic chemical elements as the body of any other living being, i.e. from carbon, hydrogen, oxygen, nitrogen and phosphorus. We differ from other mammals only in the structure and functioning of cells, tissues and organ systems.

The human body has four major features, the combination of which is unique to it - an upright skeleton, movable arms capable of manipulating objects, three-dimensional color vision and a brain of unique complexity.

The upright skeleton allows us, unlike other animals, to move on two legs. Without feeling the need to lean on the front limbs, we use flexible and sensitive fingers to explore the surface of objects.

Forward looking eyes provide binocular vision and allow us to accurately focus images, determine distance, distinguish not only color, but also shape. We can follow the movement of an object without moving our head, just by moving our eyes.

Compared to other animals, the human brain is very large relative to body size. Thanks to the brain, a person has excellent abilities for learning, logical thinking, speech control; coordination of vision and hand movements.

View models of human predecessors.

Consolidation of knowledge on the topic. Performing test tasks in notebooks from the interactive tutorial "Evolutionary Teaching". Check answers with the teacher.

Frontal conversation.

1. What are the signs of a person that make it possible to classify him as a subtype of vertebrates.

2. Indicate the signs that determine the position of a person in the class of mammals.

3. What features are common to humans and great apes?

5. List the structural features that are unique to humans.

Conclusion.

Discussion.

Together with the whole class, the question is discussed: “Who has doubts about our origin from animals?”

Nature! Man is your creation

And this honor will not be taken away from you,

But he put on his feet from all fours

And labor made an ancestor a man.

S. Schipachev

Homework. § 44, answer questions 1-3, p. 165 - 166. § 45, answer questions 1 - 3 p. 170 (question No. 3 - in writing).

What is the place of man in the system of the organic world? This question, it would seem, has been answered for a long time, which is increasingly disputed and subjected to revision.

The place of man in the system of the organic world

Briefly, we can say that the place of man is strictly defined in the classification of the organic world. He is a representative of the animal kingdom. The table shows its key ranks in the hierarchy of the biological world:

There are several groups of evidence that man is an animal and descended from them.

Animal origin of man

In favor of this they say:

Comparative anatomical evidence: a similar structure of cells, the location of organs, rudiments and atavisms in humans.

Embryological evidence: inside the womb at the initial stage of development, the baby is similar to the cubs of some animals. This is called Baer's law, and, in short, he postulates: the younger the embryo, the less specific features it has.

Physiological similarity (breathing, nutrition, etc.) of a person and an animal.

Similar chromosomal apparatus.

There are physiological features of the human species, which testify that the place of man in the system of the organic world among animals:

Upright posture, arched foot, developed muscles of the lower extremities.

The structure of the spine with 4 bends.

Movable hands.

The volume of the brain and, accordingly, the high organization of behavior.

binocular vision.

Fertility is limited: one female normally bears one fetus.

All these specific and physiological features brought man to a new stage of evolution.

Anthropogenesis and the formation of mankind

Anthropogenesis (part of the evolution that led to the emergence of man) began with hominins. Human society acquired the right to be called that and ceased to be a herd about 50 thousand years ago, when neoanthropes (Cro-Magnons) formed a new species of Homo sapiens.

The subsequent development of people began to determine the social, economic and religious laws. Progress began to go contrary to biological nature. To be a member of society, one cannot behave like a beast and obey instincts. The place and features of man in the system of the organic world turned out to be such that the very right to be called a biological species was called into question.

What distinguishes a person from the organic world

There are a number of highly developed organisms (for example, elephants or dolphins), what makes a person stand out from their background? High social component of people's life: their creative function, knowledge, work, consciousness, speech. All this makes the place of man in the system of the organic world beyond the usual limits available to other animals.

Fundamental differences between man and the organic world

The place of man in the system of the organic world and his biosocial nature sometimes contradict each other. A person does not behave like an animal in several cases:

1. He has abstract thinking.
2. Family planning, not uncontrolled reproduction, according to instinct.
3. Consciousness (not just a highly developed brain, like dolphins, for example, not only a big brain in every sense of the word).
4. Speech.
5. Man is part of society. People coexist in their artificially created habitat.

These five points reflect the social nature of man.

Abstract thinking

Abstract thinking is a human ability. Thanks to him, the place of man in the system of the modern organic world is unique. After a series of repetitions of certain actions and their consequences, many animals (especially primates) demonstrate imaginative thinking. They are able to remember the image, especially if they are hungry, but you need to imagine food. But the next step, abstract thinking, is not available to them. They are not capable of imagining and remembering, drawing a conclusion and highlighting a generalizing sign of what does not exist, what cannot be touched or smelled.

Accumulation of experience, abstract conclusions, the ability to find ways out of various situations, analyze and, based on this, make decisions and take actions, reason, generalize concepts - the privilege of people.

This article does not aim to analyze in detail the concept of abstract thinking, but it is worth giving an example of what abyss separates one of the closest relatives, chimpanzee monkeys, from people. They belong to the hominin family. A characteristic experiment on them was carried out in the laboratory. I.P. Pavlov in Koltushi near St. Petersburg.

The chimpanzee Rafael had to feast on the fire burning before eating on the ledge of the shelf. He quickly learned to use for this purpose a cup and water, which was offered to him in a tank and other containers. Then on the lake, on two rafts connected by a shaky crossing, they put food on one (as always behind the fire), and on the other a cup and a tank of water. From time to time, the chimpanzee preferred to make a difficult crossing to scoop up in a tank, but ignored a whole lake of water. It became clear that he could not generalize this concept. Water for him is tied to the image of the tank. In fairness to Raphael, it is worth adding that when the water was removed from the tank, in the end, albeit by accident, he scooped up water from the lake and, having put out the fire, got a treat.

creation

The place of man in the system of the organic world is already the whole planet. People do not live strictly within the boundaries of the place of birth, but adjust the chosen place of life to suit their needs. And this is not always the most comfortable living environment. But people are transforming it. This is the simplest creation, responsible for covering the urgent needs, but which arose as a result of a conscious choice of life in an unsuitable environment. People are literally going against biological selection. They do not look for the easiest habitats, but adapt very unsuitable ones.

There is creative creation. The desire to leave a mark on history, to influence the world around us, and not just to feed oneself.

Speech

Another sign of abstract human thinking is speech. Even its very possibility. When certain natural phenomena are assigned a specific (and, by the way, abstract) concept - a word and its semantic meaning. It is not directly related to how and what the senses perceive in a particular period of time here and now. The image that each person forms about objects, of course, carries information-memories about weight, temperature and other associations. But with the help of words, non-existent objects are also described, those that cannot be touched with hands. Favorite examples of scientists are love or mathematical terms. How to describe the concept of seven?

Man is just a highly evolved animal

This problematic issue. Evidence of the animal nature and the origin of man is considered. According to biology, the place of man in the system of the organic world. There are anthropological factors that to some extent explain how physiological characteristics as a result could influence the formation of a highly developed individual and human society. But there is a long series of social factors that put a person on another level. Is it possible to speak of a separate fifth kingdom of the organic world? Or continue to put forward theories on the topic: where did our family come from? Is the soul a matter separate from the body, or are they physiological processes that mimic consciousness, but remain chemistry?

To reconcile opposites, it is customary to talk about the biosocial nature of man.

The school curriculum has not yet moved away from a strict focus on evolution. Teachers of biology and zoology do not always correctly emphasize that Darwin only put forward a theory. It is popular, but not supported by hard evidence. On the contrary, there are still many questions, white spots and arguments against it.

Although the basic postulates of this theory are an obligatory part of the school curriculum, and it is necessary to know them in order to be an educated person with a broad outlook. But what speaks against the theory of the origin of species, except that the social nature of man is pronounced, and thinking is unique?

Darwin's theory of the origin of species: the main arguments against

As Darwin himself and his contemporaries argued: the idea of ​​evolution was in those days in the air. The genius of the most famous naturalist, the author of The Origin of Species, lies in the fact that he formulated how the big comes from the small in billions of years. It is not the strongest who survive, but the most adapted to the constant changes in the environment. This is the shorthand for natural selection.

Opponents of Darwinism turn to the concept of irreducible complexity. In the process of evolution, many organisms could not gradually form (due to mutations) the advantages that they possess at a given stage of development and thanks to which they survived in a certain habitat, in other words, they underwent natural selection.

Another main argument against the theory of evolution is the informational complexity of chromosomes and, as a consequence, of the DNA molecule. Such an ordered and long chain could not have been obtained by chance, even in billions of billions of years. In addition, with the enormous age of the Earth and the discovered fossils dating from very different periods, a sufficient number of missing links, transitional life forms, which the theory of evolution assumes in large volume between all species, have not been found.

The question of origin is most closely connected with the place of man in the system of the organic world and his role. Perhaps it is the social component of people's lives that determines. It imposes on humanity responsibility for the entire biosphere. The role, the place of a person in the system of the organic world is not given to him in vain - to protect and reasonably dispose of the planet, regardless of whether people are part of an ecosystem, or simply similar to other biological organisms, but have a higher origin and purpose of existence.

And with it, the position of man in the system of the animal world, it is not necessary to plunge into the past, because evolution is a process that takes place always and everywhere around us. For example, bacteria that were easily destroyed by penicillin in the past have acquired a new, antibiotic-resistant form.

Natural selection

Nature decreed as follows: the better an animal is adapted to the conditions of the area in which it lives, the greater its chances of surviving and having offspring. His children may inherit the abnormalities that made the father's animal so successful in its local environment. Animal species change over time, better adapting to environmental conditions. New species arise, live for thousands or millions of years, and then disappear. Evolution needs time and happy occasions for change to occur.

Traits that may help a species survive, such as better teeth or a larger brain, may appear in newborns as random abnormalities. If new traits really help to survive, and animals can live longer, or survive under conditions in which a normal member of the species dies, then these traits will be passed down from generation to generation. When these abilities are really useful, animals that have them will gradually crowd out those that do not.

Darwin's theory

According to Darwin's theory, any living being does not produce an identical copy of itself in the course of its life. A child is not like a mother, a kitten is not like a mother cat, even grains of wheat are different from each other. If you examine them under a microscope or conduct a chemical analysis, you can notice their dissimilarity. Variation is the material for natural selection. If these properties are necessary for the life of a new creature, then it will live and produce offspring, if not, then merciless natural selection will remove it from the biological sphere, and it will die like hundreds and thousands of unadapted individuals. What is the position of man in the system of the animal world? The most mysterious selection of nature, as well as its crown, of course, is man.

The position of man in the system of the animal world

Humans are classified as primates, of which there are more than 100 species, including great apes, gorillas and chimpanzees. If you indicate the position of a person in the system of the animal world, primates, namely chimpanzees, have the closest family ties with humans, 98.4% of their genes coincide. It is proved that 2.6 million years ago there was a division of primates into 2 branches. 1 - in Australopithecus, later extinct, and 2 the position of man in the system of the animal world, - in a skilled man. It is known that the first anthropoids existed on Earth 3-5 million years ago.

A lot of research, measurements, excavations and, based on them, scientific evidence, indicates that the position of man in the system of the animal world is classified as a species of primates. All primates have common features.

1. All have hands and feet with five fingers each.
2. There are teeth that are adapted to chew a lot of different foods.
3. All give birth mainly to one cub, less often - to several children.

Signs of the position of man in the system of the animal world

But there are also significant differences between them.

1. Only man is characterized by upright posture on two legs and, accordingly, a special structure of the spine, pelvis, legs, arms, muscles and other organs.
2. The human hand can perform many different and precise movements. The human skull is taller and rounder;
3. The brain part of the skull dominates over the facial part, has a high forehead, weak jaws with small fangs, the chin is clearly defined.
4. The human brain occupies a volume of 1800 cm3, which is 3 times larger than the brain of primates. A person has well-developed parts of the brain, where the most important mental and speech centers are located.

The first human among primates

The very first human ancestor - Australopithecus, could already move in an upright position. Thanks to this, he could hold tools and primitive weapons in his hands.

According to scientific theory, the emergence of Homo sapiens did not happen suddenly, it was the result of a long evolutionary development that took tens of millions of years. Scientists have given the name "homo sapiens" to a person who knows how to make elementary tools, as well as bury his fellow tribesmen. The most primitive tools were turned stones. 500 thousand years ago, people were already processing wooden sticks, making spears out of them. And only 250 thousand years ago appeared

50 thousand years ago they learned how to make lamps carved from stone, in which instead of fuel there was animal fat, after another 20 thousand years the first bow and arrows appeared. From the original ancestral species to the Homo sapiens species, leaps in development took place over 14-20 million years. Further evolution led to the emergence of Australopithecus, able to use the surrounding objects as tools, and even subject them to elementary processing.

Human development

When primates divided into two branches: the first subspecies in the course of evolution turned into a skilled man, and the second into an African Australopithecus, later extinct. Evolution made a leap when the species "handy man" arose. He mastered elementary thinking and speech, the main carriers of information, which was then passed on to the next generations. The species "upright man" arose 100 thousand years ago. With its appearance, the amount of information has significantly increased, which contributed to the creation of a new type of heritage - not genetically, but through material and spiritual experience. This one was equal to 1250 cm3, but its evolution did not stop there. At this stage of development, there was an accelerated progress of biological changes.

Considering the position of man in the system of the animal world, it can be briefly described as follows.

The earliest people were engaged in gathering and hunting. They led a nomadic life, eating plants and meat of animals that came across them on the way. They used caves for housing, but ancient finds confirm that the first dwellings were built from branches during this period. At some point, the tribes realized that a permanent home has a number of advantages. In a safe place, you can hide food supplies for hungry periods, protect yourself from bad weather and predators. In such villages it is more convenient to get along with each other, and it is also easier to fight off the enemy. In the process of evolution, the human brain has grown disproportionately to the body. But the most important achievement: people have become a collective active entity, the main components of which are labor, reason and speech, and this is the main difference between people and animals.

Man and animal world

The position of man in the system of the animal world has a powerful impact on this world. Paleolithic man was already hunting, exterminating now extinct creatures. Animals, birds and fish gave people food, the skins served as the first clothes, shoes and household items. Ever since people began to eat meat, they have learned how to make fire and tame animals. With the improvement of hunting tools and taming, the animal world increased.

Evolution in our time no longer matters for man, rather, on the contrary, he has a global impact on the environment. The position of man in the modern system of the animal world poses a danger to the biological diversity of species. It comes from human activities, and is associated with a change in the habitat of animals, global climate change, breeding of exotic species and the spread of diseases. Regardless of skin color, shape and size, all mankind belongs to one species - "reasonable man." Human behavior reflects how evolution has programmed it to act, such as looking for a mate, filling your stomach, or running away from danger.

Evolution or outside interference?

Everything seems to be simple and clear in the evolutionary theory of the origin of man. Nevertheless, scientists have not yet come to a single and undeniable statement of what exactly became the impetus for the transition from primates to Homo sapiens.

According to various theories, there could be external interference, such as the interbreeding of representatives of extraterrestrial civilizations with human ancestors or the control of evolution by the forces of an extraterrestrial superintelligence.

Thanks to the intellect, a person has made a huge breakthrough: he can take care of himself, make a choice or take a risk. He knows how to write, compose music, draw with paints. And also build planes and ships to explore the entire planet, as well as spaceships to explore space.

In this lesson, you will learn about the relationship of man with other animal species. Find out the systematic position of the species Homo sapiens in the modern classification of living beings, get acquainted with the features that unite us with other mammals. We will also consider the features of the structure of our body, which distinguish a person from other animals and make our biological species unique and inimitable among other unique species.

Man, as a living being, is part of the animal world. Our species belongs to the phylum Chordates, the subtype Vertebrates, the class Mammals, the subclass Placental mammals, the order Primates, the family Hominids, the genus Man, and the species Homo sapiens (Scheme 1).

Scheme 1. The place of man in the system of living organisms

The fact that our species belongs to the Animal kingdom is convincingly proved by our morphology, cytology and physiology.

Belonging to the type of Chordata is visible at the stage of intrauterine development. The human embryo has a notochord, a neural tube located above the notochord, a heart located on the ventral side under the digestive tract.

The belonging of a person to the Vertebrate subtype is determined by the replacement of the notochord by the spine, the developed skull and jaw apparatus, as well as two pairs of limbs (Fig. 1) and the brain, consisting of five sections.

Rice. 1. Human and frog skeletons have similar features that are characteristic of all vertebrates

The presence of hair on the surface of the body, five sections of the spine, a four-chambered heart, a highly developed brain, sweat, sebaceous, and mammary glands, as well as warm-bloodedness, make it possible to attribute a person to the class of Mammals.

The development of the fetus inside the mother's body in the uterus and its nutrition through the placenta - to the subclass of placental mammals.

The presence of grasping forelimbs, in which the first finger is opposite to the rest of the fingers, nails, well-developed clavicles, as well as the change of milk teeth in the process of ontogenesis and the bearing of, mainly, one cub, makes it possible to classify a person as a Primate. At the order level, the resemblance between humans and other animals ends.

The features that distinguish the Human family from other primates are unique to humans. In the family People there is only one genus Man, in which there is only one modern species Homo sapiens.

Consider the features that distinguish humans from other animals.

First of all, it is a higher nervous activity. A person has a developed second signaling system (see the lesson of grade 8, Higher nervous activity), which is responsible for the perception of speech, and logical thinking, memory, and abstract thinking are well developed. These abilities arise due to the developed cerebral cortex. Humans have the largest ratio of brain mass to body mass among all animals.

The second difference is the features of the skeleton responsible for true upright posture. Our spine has 4 curves that optimally transfer the weight of our upright body to the legs (Fig. 2).

Rice. 2. The human spine is adapted to true upright posture

And the legs have arched feet that withstand the load when running and jumping (see video).

A flexible hand, in principle, is characteristic of many primates, but only in humans has it reached such flexibility that it makes it easy to manipulate both small and heavy objects.

Moreover, the movements can be both powerful and very subtle, allowing, for example, to embroider or write (see video).

Upright posture, developed hands and a powerful brain allowed man to produce tools - from a pointed stick to a space satellite (Fig. 3).

Rice. 3. Artifacts of ancient (spears - on the left) and modern (space satellite - on the right) man

Some birds and other primates are able to use found tools, such as stones and sticks. But none of them is able to make a special tool for themselves.

The second signaling system made it possible to create a very highly organized society. No flock of animals is capable of such subtle and effective interaction as human society (see video).

Thus, from the biological standpoint of taxonomy, a person is an animal from the order Primates. It has all the tissues and organ systems characteristic of other primates.

The human genotype differs from the genotype of the closest great apes, such as bonobo pygmy chimpanzees, by one percent. At the same time, a person, unlike animals, has a developed abstract thinking, is able to produce and use tools. He exists in a society in which there is a division of labor and which is governed by speech.

Bibliography

1. A.A. Kamensky, E.A. Kriksunov, V.V. Beekeeper. General biology, grades 10-11. - M.: Bustard, 2005. Download the textbook from the link: ( )
2. D.K. Belyaev. Biology 10-11 class. General biology. A basic level of. - 11th edition, stereotypical. - M.: Education, 2012. - 304 p. (

Man has a very ancient evolutionary lineage. Among the more and more ancient ancestors are: lower ape, semi-monkey, lower placental mammal, primitive marsupial mammal, monotreme mammal, reptile, amphibian, lungfish, ganoid fish, primitive chordate animal of the lancelet type, common ancestor of the lancelet and ascidians in the form of an invertebrate . At the very beginning of the animal world are the first living beings, which are thus the starting point of development for man. The human egg is in some way reminiscent of this initial stage of phylogenetic evolution.

According to the structure and arrangement of its organs, a person belongs to the class of mammals. The most significant features inherent in both humans and mammals are the mammary, sebaceous and sweat glands, body hair, specialized teeth (incisors, canines, premolars and molars), a four-chambered heart and the left aortic arch, pulmonary respiration, the presence of a diaphragm, highly developed brain, intrauterine development of the embryo, feeding the baby with milk. Both in humans and animals, there are single links of tissue metabolism, growth and individual development are carried out in a similar way, the principle of storage and implementation of the genetic code, which is common for the entire organic world, etc. The maximum similarity of a person is found with representatives of the family of great apes, or anthropoids: gorilla chimpanzee, orangutan, gibbon.

It is almost impossible to distinguish between human embryos, primates and other vertebrates in the early stages of development. In the human embryo, a notochord, gill grooves, gill arches and a corresponding network of blood vessels are formed, just as is the case with the most ancient shark fish. Some features of the "fish stage" of development can manifest themselves in a person in the form of atavisms. An example is cervical fistulas communicating with the pharynx. In the process of embryonic development, a number of other similar signs appear and then disappear in a person, but some of them remain in the form of rudiments, indicating a clear connection with the animal world. These include: the coccyx - the remainder of the tail, expressed in the spine of the embryo at the age of 1.5-3 months of intrauterine development, the outer hairline, the appendix of the caecum, subcutaneous muscles, which are developed in humans only on the face and in the form of a rudiment there is subcutaneous ear muscle, etc. In total, a person has more than 90 rudiments.

From reptiles, a person inherited a number of features that are found mainly in the fetal period, for example, in the development of the brain, the structure and nature of the articulation of the limbs in a fetus of several months.

The nature of the distribution of hair on the body of the fetus in groups - three and five pieces to a certain extent corresponds to the way the scales are located on the skin of the ancient reptiles that served as the ancestors of mammals. Among the later ancestors of man were ancient mammals, as evidenced by even more facts. Thus, the brain of a human fetus at the early stages of development, with its smooth surface and primitive structure, strongly resembles the brain of modern lower mammals (these features are inherited by humans, probably from their Mesozoic forms).

The kinship of man with the lower mammals is also evidenced by other primitive traits found in his ontogeny. For example, in a human six-week-old fetus, the rudiments of several pairs of mammary glands are formed along the lactiferous lines. Throughout the body (except for the palms and soles) a rather thick, albeit small, hair fluff develops. In the oral cavity, noticeable ridges form on the soft palate, in a pronounced form so characteristic of monkeys, carnivores and other mammals.

A similar shape of the external ear is characteristic of human fetuses at the age of 5-6 months and is obviously inherited from a fossil lower monkey, in some respects similar to macaques and constituting one of the links in our family tree. In the case of incomplete wrapping of the shell helix, a small skin growth in the form of a tubercle, called "Darwin's", is formed on its upper lateral section.

The number of atavisms from the stage of mammals also includes: an unusually strong development of the ear muscles, which allows a person to move the auricle; development of the morgan's ventricles of the larynx to a depth of more than 1 cm; extra mammary glands, or nipples; the rudiments of some extra teeth; excessive hairiness on the body and face; tail. Every human being has a appendix of the caecum, or appendix: this vestigial organ is indisputable evidence that our ancestors at the stage of lower mammals possessed a rather long caecum. In some modern mammals, such as rodents, ungulates, an energetic process of digestion of food masses takes place in the caecum.

The appendix is ​​one of the many vestiges of the human body. An extremely characteristic feature of rudiments as residual organs is the strong variability of their shape, size, and structure. So, with an average length of 8-9 cm, the human appendix sometimes reaches 20-25 cm, as in great apes; it can also be greatly shortened, up to 1-2 cm, and in very rare cases it is completely absent. Being rich in lymphoid tissue, especially at a young age, the appendix seems to correspond to some part of the caecum of other mammals that do not have an appendix.

At one time, Charles Darwin provided convincing evidence of the phylogenetic commonality of emotions and ways of expressing them, devoting a separate essay to them, closely related to The Descent of Man. In The Expression of the Emotions in Man and Animals, published in 1872, Darwin successfully showed that, in terms of the features of elementary mental activity and the ways of expressing sensations, man is undoubtedly genetically related to monkeys. Another important conclusion is that there are no psychic differences among the human races.

C. Darwin at one time concluded that none of the modern great apes is the direct ancestor of humans. The genealogy of man is a long chain of his predecessors, it goes back into the depths of time for tens of millions of years, and the last link before the first people was the fossil anthropoid ape. Unknown during the life of Darwin, the fossil precursor of man was subsequently discovered, confirming the scientific prediction of the scientist.