The appearance in the process of human embryonic development of a notochord, gill slits in the pharyngeal cavity, a dorsal hollow neural tube, and bilateral symmetry in the structure of the body determines whether a person belongs to the Chordata type. The development of the spinal column, the heart on the ventral side of the body, the presence of two pairs of limbs - to the subphylum Vertebrata. Warm-bloodedness, the development of mammary glands, and the presence of hair on the surface of the body indicate that a person belongs to the class of Mammals (Mammalia). The development of the baby inside the mother’s body and the nutrition of the fetus through the placenta determine a person’s belonging to the Placental subclass (Eutheria). Many more specific characteristics clearly define the position of a person in the system of the Primates order.

So, from a biological point of view, humans are one of the species of mammals belonging to the order of primates, the suborder of the narrow-nosed.

The place of Homo sapiens in the modern classification is as follows:

1. Subspecies Homo sapiens sapiens

2. Species Homo sapiens

4. Tribe Homini

5. Subfamily Homininae

6. Family Hominidae

7. Superfamily Hominoidea

8. Section Catarrhini

9. Suborder Harlorhini (Antropoidea)

10. Primates Squad

Comparative anatomical evidence. The animal origin of man is evidenced by the presence of rudimentary organs and atavisms.

Rudiments are organs that, in the process of evolution, have lost their original meaning. There are only 90 rudiments in the human body:

1. coccygeal vertebrae (remnant of the caudal region);

2. poorly developed hair on the body;

3. subcutaneous muscle;

4. muscles that lift the hair;

5. muscles that move the ears;

7. brow ridges in the skull;

8. wisdom teeth;

9. appendix – cecum;

10. in the corner of the eye - the third eyelid;

11. in the circulatory system - the median sacral artery.

Atavisms are evidence of animal origin. These are deviations from the norm.

Atavisms are the appearance of characteristics characteristic of distant ancestors. These are characteristics that were laid down in embryonic development, but did not disappear, but remained for life in the human genotype:

o several pairs of nipples – multi-nipple;

o hair – polymastia throughout the body;

o cervical fistula – as a result of non-closure of the gill slit;

o strong display of fangs;

o well-developed tubercle in the corner of the ear.

o Atavisms that disrupt normal life activities:

o hole in the interventricular septum of the heart;

o the opening between the atria is the ductus botallis.

Comparative anatomical evidence includes: the same structure of the musculoskeletal, circulatory, respiratory, excretory and other organ systems in humans and monkeys. Embryological evidence of human animal origin.

Embryology is a science that studies the embryonic development of organisms.

At the early stages of development, the human embryo has characteristics of lower vertebrates:

ü cartilaginous skeleton - notochord;

ü gill arches;

ü symmetrical departure of blood vessels from the heart;

ü smooth surface of the brain.

Later, features characteristic of mammals appear:

Ø thick hair on the fetal body;

Ø several pairs of nipples;

Ø left-sided aortic arch;

Ø constant body temperature;

Ø the body cavity is divided by the diaphragm: into the thoracic and abdominal sections;

Ø mature red blood cells;

Ø teeth have two shifts (deciduous and permanent) and are divided into 3 groups;

Ø there is not a single bone in the human skeleton that mammals do not have;

Ø there are 3 auditory ossicles in the inner ear;

o A 6-month-old human fetus is covered with hair. Similarities between humans and apes

o Equal expression of feelings of joy, anger, sadness.

o Monkeys gently caress their babies.

o Monkeys take care of children, but also punish them for disobedience.

o Monkeys have a well-developed memory.

o Monkeys are able to use natural objects as simple tools.

o Monkeys have concrete thinking.

o Monkeys can walk on their hind legs, supported by their hands.

o Monkeys have nails on their fingers, like humans, rather than claws.

o Monkeys have 4 incisors and 8 molars - just like humans.

o Humans and monkeys have common diseases (influenza, AIDS, smallpox, cholera, typhoid fever).

o Humans and apes have a similar structure of all organ systems.

o Biochemical evidence of the closeness of humans and monkeys:

o the degree of DNA hybridization between humans and chimpanzees is 90-98%, humans and gibbons - 76%, humans and macaques - 66%;

o Cytological evidence of the proximity of humans and monkeys:

o humans have 46 chromosomes, chimpanzees and monkeys have 48, gibbons have 44;

o in the chromosomes of the 5th pair of chimpanzee and human chromosomes there is an inverted pericentric region

All of the above facts indicate that humans and apes descended from a common ancestor and make it possible to determine the place of humans in the system of the organic world. Humans belong to the phylum of chordates, the subtype of vertebrates, the class of mammals, and the species Homo sapiens.

The similarity between humans and monkeys is proof of their relatedness and common origin, and the differences are a consequence of different directions of evolution of monkeys and human ancestors, especially the influence of human labor (tool) activity. Labor is the leading factor in the process of transformation of a monkey into a human.

The most characteristic feature of man, distinguishing him from anthropomorphic monkeys, is the exceptionally strong development of the large brain. In terms of body weight, humans occupy approximately the middle place between gorilla and chimpanzee. Data on the size of the brain in humans and other primates are given in table. 11 and in Fig. 13.9.

The large human brain differs from the large brain of anthropomorphic monkeys not only in its large mass, but also in other important features: the frontal lobe and parietal lobes are more developed, and the number of small grooves is increased. A significant part of the human cortex is associated with speech: the “motor center” of speech, the “auditory center”. There is a greater richness of interneuron contacts. New qualities arose in man - sound and written language, abstract thinking. Many human anatomical features are associated with upright posture and labor activity, which required the restructuring of many organs. The human spinal column has characteristic curves in the sagittal plane (lordosis and kyphosis), the chest has a flattened shape, and the pelvis is expanded, as it takes on the pressure of the internal organs (Fig. 13.10).

A person is characterized by a significant strengthening of the connection between the spinal column and the pelvis, more massive lower limbs: the femur is the most powerful bone in the skeleton, it can withstand a load of up to 1650 kg. The muscles of the lower extremities are also highly developed: the gluteal muscles, which provide abduction and extension of the hip, the greater sciatic muscle (prevents the body from tilting forward), the calf muscle and the calcaneal tendon (Fig. 13.11). The foot is a supporting organ and has a high arch, unlike the flat foot of monkeys.

A person's first finger is less mobile. In monkeys, the upper limbs are adapted to suspend the body in an extended state and to move through trees by “brachiation.” The first fingers and toes are short (Fig. 13.12), they act as a hook when hanging on a branch. When moving on the ground, the long forelimbs serve as additional support. In humans, the upper limbs, which do not perform the function of support, are shortened and less massive (Fig. 13.13). For fast free movements, excessively large limbs of the hands would be disadvantageous.

A person has increased mobility of the hand, which allows for greater freedom of movement and ensures their variety. The first finger is much better developed, its muscles are more differentiated.

Humans are characterized by the dominant development of the cerebral part of the skull, the absence of the sagittal and occipital ridges, to which the masticatory muscles are attached in monkeys, and the weaker development of the supraorbital relief (supraorbital ridges). The facial part of the skull, unlike monkeys, is less developed (Fig. 13.14), which is associated with a decrease in the massiveness of the masticatory apparatus; the mass of the lower jaw as a percentage of the mass of the skull in a gorilla is about 45%, and in humans only 15%.

The teeth are relatively small in size; a typical sign of a person is the absence of a conical shape of the fangs and their smaller size. The development of a chin protrusion is characteristic, which is not observed in any of the monkeys; this protrusion is absent in the ancient ancestors of humans. The formation of the chin is associated with reduction of the alveolar part, straightening of the teeth and the growth characteristics of the bones of the facial skull. Human hair is reduced. These features indicate a fundamental difference between humans and animals, including monkeys.

All modern primates are not the ancestors of humans; they separated from the common trunk of ancestral forms back in the Tertiary period. There are two trends in the understanding of human nature; on the one hand, a misunderstanding of the qualitative specificity of man and the reduction of his characteristics only to quantitative ones (vulgar biologization), on the other hand, an opposite nihilistic attitude towards the biological basis of man, contrasting him with other living organisms, separating him from the animal world and from nature, of which he is a part . Dialectical materialism will provide the basis for the scientific definition of the essence of man, who has a dual nature: biological and social

79. Paleontological data on the origin of primates and humans. Parapithecus, Dryopithecus, Australopithecus, Archanthropus, Paleoanthropus, Neoanthropus. Scientists claim that modern man did not descend from modern apes, which are characterized by narrow specialization (adaptation to a strictly defined way of life in tropical forests), but from highly organized animals that died out several million years ago - dryopithecus. The process of human evolution is very long, its main stages are presented in the diagram.

The main stages of anthropogenesis (the evolution of human ancestors)

According to paleontological finds (fossil remains), about 30 million years ago ancient primates Parapithecus appeared on Earth, living in open spaces and in trees. Their jaws and teeth were similar to those of apes. Parapithecus gave rise to modern gibbons and orangutans, as well as the extinct branch of Dryopithecus. The latter in their development were divided into three lines: one of them led to the modern gorilla, the other to the chimpanzee, and the third to Australopithecus, and from him to man. The relationship of Dryopithecus with humans was established based on a study of the structure of its jaw and teeth, discovered in 1856 in France.

The most important stage on the path to the transformation of ape-like animals into ancient people was the appearance of upright walking. Due to climate change and forest thinning, a transition has occurred from an arboreal to a terrestrial way of life; in order to better survey the area where human ancestors had many enemies, they had to stand on their hind limbs. Subsequently, natural selection developed and consolidated upright posture, and, as a consequence of this, the hands were freed from the functions of support and movement. This is how Australopithecines arose - the genus to which hominids (family of humans) belong..

Australopithecus

Australopithecus- highly developed bipedal primates that used objects of natural origin as tools (hence, Australopithecus cannot yet be considered human). Bone remains of Australopithecines were first discovered in 1924 in South Africa. They were as tall as a chimpanzee and weighed about 50 kg, their brain volume reached 500 cm 3 - according to this feature, Australopithecus is closer to humans than any of the fossil and modern monkeys.

The structure of the pelvic bones and the position of the head were similar to those of humans, indicating an upright position of the body. They lived about 9 million years ago in the open steppes and ate plant and animal foods. The tools of their labor were stones, bones, sticks, jaws without traces of artificial processing.

A skilled man

Not having a narrow specialization of the general structure, Australopithecus gave rise to a more progressive form, called Homo habilis - a skilled man. Its bone remains were discovered in 1959 in Tanzania. Their age is determined to be approximately 2 million years. The height of this creature reached 150 cm. The volume of the brain was 100 cm 3 larger than that of australopithecines, the teeth of the human type, the phalanges of the fingers were flattened like those of a person.

Although it combined the characteristics of both monkeys and humans, the transition of this creature to the manufacture of pebble tools (well-made stone) indicates the appearance of its labor activity. They could catch animals, throw stones and perform other actions. The piles of bones found with the Homo habilis fossils indicate that meat became a regular part of their diet. These hominids used crude stone tools.

Homo erectus

Homo erectus is a man who walks upright. the species from which modern humans are believed to have evolved. Its age is 1.5 million years. Its jaws, teeth and brow ridges were still massive, but the brain volume of some individuals was the same as that of modern humans.

Some Homo erectus bones have been found in caves, suggesting its permanent home. In addition to animal bones and fairly well-made stone tools, heaps of charcoal and burnt bones were found in some caves, so, apparently, at this time, Australopithecines had already learned to make fire.

This stage of hominid evolution coincides with the settlement of other colder regions by people from Africa. It would be impossible to survive cold winters without developing complex behaviors or technical skills. Scientists hypothesize that the prehuman brain of Homo erectus was capable of finding social and technical solutions (fire, clothing, food storage, and cave dwelling) to the problems associated with surviving the winter cold.

Thus, all fossil hominids, especially australopithecus, are considered to be the predecessors of humans.

The evolution of the physical characteristics of the first people, including modern man, covers three stages: ancient people, or archanthropes; ancient people, or paleoanthropes; modern people, or neoanthropes.

Archanthropes

The first representative of the archanthropes - Pithecanthropus(Japanese man) - ape-man, upright. His bones were found on the island. Java (Indonesia) in 1891. Initially, its age was determined to be 1 million years, but, according to a more accurate modern estimate, it is slightly more than 400 thousand years old. The height of Pithecanthropus was about 170 cm, the volume of the skull was 900 cm 3.

Existed somewhat later Sinanthropus(Chinese person). Numerous remains of it were found in the period 1927 to 1963. in a cave near Beijing. This creature used fire and made stone tools. This group of ancient people also includes Heidelberg Man.

Paleoanthropes

Paleoanthropes - Neanderthals appeared to replace the archanthropes. 250-100 thousand years ago they were widely distributed throughout Europe. Africa. Western and South Asia. Neanderthals made a variety of stone tools: hand axes, scrapers, pointed points; they used fire and rough clothing. Their brain volume increased to 1400 cm3.

The structural features of the lower jaw show that they had rudimentary speech. They lived in groups of 50-100 individuals and during the advance of glaciers they used caves, driving wild animals out of them.

Question 1. Describe the systematic position of man in the animal world.
Man belongs to the phylum Chordata, subphylum Vertebrates, class Mammals, subclass Placentals, order Primates, suborder Anthropoid (anthropoids - Great Apes) primates, superfamily Greater apes, family Hominids (Humans), the only genus Homo with the only species Homo sapiens (Homo Sapiens).
In addition to the anthropoid suborder, primates also include lemurs and tarsiers.

Question 2. Indicate the characteristics of humans as a representative of the class of mammals.
Humans can be classified as Mammals based on the following characteristics:
seven cervical vertebrae;
hair, sweat and sebaceous glands of the skin;
well developed lips and muscular cheeks;
diaphragm and alveolar lungs;
the auricle and three auditory ossicles of the middle ear;
one aortic arch (left) and anucleated red blood cells;
warm-blooded;
mammary glands, care of offspring;
similarities in embryo development.

Question 3. What characteristics are common to humans and apes?
Humans and apes (ponids) are similar in their large body size, the absence of a tail and cheek pouches, good development of facial muscles, and a similar structure of the skull and skeleton in general. In addition, what humans and apes have in common are blood types and the Rh factor, similarity of chromosomes (out of 23 chromosomes, 13 are similar to chimpanzees), various diseases, a long gestation period and a long prepubertal (pre-reproductive) period. They are also united by a high level of development of higher nervous activity, the ability to learn quickly, the ability to use tools, good memory, and rich emotions. An example is experiments on teaching apes the language of deaf-mutes, during which gorillas and chimpanzees learned up to 200-300 sign words. The human and chimpanzee genomes are 98.5% identical.

Question 4. List the structural features that are unique to humans.
There are differences between humans and animals.
Man is a social being who produces tools and uses them to influence nature. A person has a highly developed brain, possesses consciousness, thinking, articulate speech and a number of anatomical features that arose in connection with labor activity, which is unique to humans. The differences are related to the direction of evolution. Man and apes are two branches of the order of primates, which in relatively recent times separated from the common genealogical trunk.
It is typical for a person to:
1. Adaptation to upright walking. The spine has acquired an S-shaped curvature, the foot has a dome shape. These are the main devices that provide shock absorption and shock absorption when walking and jumping, which is important for protecting the brain. The big toe functions as a support. The pelvis is wider, it takes on the pressure of the organs in an upright position. The chest is flat, compressed laterally, due to the pressure that the internal organs exert on the ribs, due to the horizontal position of the body when walking. The brain part of the skull has increased and dominates the facial part. There are no brow ridges. The jaws and chewing muscles are less developed. In the lower part of the body, the gluteal, quadriceps, gastrocnemius, and soleus muscles are especially developed. The consequences of upright walking are associated with limited speed of movement, hypertension, immobile sacrum, dilated veins in the legs, and osteochondrosis.
2. The presence of a flexible hand - an organ of labor adapted to complex movements. The human hand is specialized as a grasping organ; the thumb is well mobile. A person's arms are shorter than his legs.
3. The brain is well developed. In humans, the temporal, frontal and parietal lobes are highly developed, where the main centers of higher nervous activity are located. The surface of the brain is 1250 cm2. The surface area of ​​the cortex in the frontal region is twice that of great apes. The appearance of speech, abstract thinking, and consciousness is characteristic.
4. Hairless skin has become a giant receptor field capable of bringing additional information to the brain. This was a factor in the intensive development of the brain. "Balding" of the skin is the last biological prerequisite for the development of man as a creative social being.

Question 5. Which
The increase in the size and complexity of the structure of the brain provided a person with the opportunity to develop many functions, such as highly organized nervous activity, the ability to learn, the presence of a large amount of memory and complex emotions, speech. They also contributed to the emergence of abstract thinking and the ability to work. The centers associated with the senses provide the finest analysis of visual and auditory information, which allows us to perceive and understand facial expressions and speech. The motor centers of the brain exercise extremely precise and operational control of the muscles of the fingers, vocal cords, etc. In many ways, it was the development of the brain that allowed man to reach the high stage of evolutionary development that he now occupies.

What is the place of man in the system of the organic world? This question seems to have been answered long ago, but is increasingly being challenged and revised.

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

They say in favor of this:

Comparative anatomical evidence: similar cell structure, arrangement of organs, rudiments and atavisms in humans.

Embryological evidence: Inside the womb, at the initial stage of development, the baby is similar to the young of some animals. This is called Beer's law, and, in short, it postulates: the younger the embryo, the less specific characteristics it has.

Physiological similarities (breathing, nutrition, etc.) between humans and animals.

Similar chromosomal apparatus.

There are physiological characteristics of the human species that indicate that man’s place 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 curves.

Movable hands.

Brain volume and, accordingly, high organization of behavior.

Binocular vision.

Fecundity is limited: one female normally bears one fetus.

All these species and physiological characteristics brought man to a new stage of evolution.

Anthropogenesis and the formation of humanity

Anthropogenesis (the part of evolution that led to the emergence of humans) began with hominids. Human society gained 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, Homo sapiens.

Social, economic and religious laws began to determine the subsequent development of people. Progress began to go against biological nature. To be a member of society, you cannot behave like an animal and obey your instincts. The place and characteristics 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 sets a person apart from the organic world

There are a number of highly developed organisms (for example, elephants or dolphins), what makes humans stand out from them? The high social component of people’s lives: their creative function, knowledge, work, consciousness, speech. All this takes the place of man in the system of the organic world beyond the usual framework accessible to other animals.

Fundamental differences between humans and the organic world

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

These five points reflect the social nature of man.

Abstract thinking

Abstract thinking is an ability inherent only to humans. Thanks to him, man’s place 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, and they 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 identifying a generalizing feature of something that does not exist, that cannot be touched or smelled.

The 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 examine in detail the concept of abstract thinking, but it is worth giving an example of the gulf that separates one of the closest relatives - chimpanzees - from people. They belong to the family Hominidae. A typical experiment on them was carried out in the laboratory named after. I.P. Pavlova in Koltushi near St. Petersburg.

The chimpanzee Raphael had to put out the fire that was burning on the ledge of the shelf before eating. He quickly learned to use a cup and water for this purpose, which was offered to him in a tank and other containers. Then on the lake, on two rafts connected by a shaky crossing, they placed food on one (behind the fire, as always), and on the other a cup and a tank of water. The chimpanzee time and time again chose to make a difficult crossing to scoop up something in the tank, but ignored the whole lake of water. It became clear that he could not generalize this concept. For him, water is tied to the image of a tank. To be fair 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, after putting out the fire, received a treat.

Creation

The place of man in the system of the organic world is already the entire planet. People do not live strictly within the boundaries of their place of birth, but adapt the chosen place of life to 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 urgent needs, but which arose as a result of the conscious choice of living in an unsuitable environment. People are literally going against biological selection. They do not look for the easiest possible 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 ourselves.

Speech

Another sign of human abstract 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 specific 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 words are also used to describe non-existent objects, 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 simply a highly developed animal

This is a problematic issue. Evidence of animal nature and human origins is considered. According to biology, man’s place 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 a different level. Is it possible to talk about a separate fifth kingdom of the organic world? Or continue to put forward theories on the topic: where did our race come from? Is the soul a separate matter from the body, or are these physiological processes that imitate 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. Biology and zoology teachers do not always correctly emphasize that Darwin only put forward a theory. It is popular, but not supported by irrefutable evidence. On the contrary, there are still many questions, blind spots and arguments against.

Although the basic postulates of this theory are a mandatory 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 clearly expressed and his 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 the air at that time. The genius of the most famous naturalist, the author of “The Origin of Species,” is that he formulated how from the small, over billions of years, the big comes. It is not the strongest who survive, but the one most adapted to constant environmental changes. This is a brief formulation of natural selection.

Opponents of Darwinism appeal to the concept of irreducible complexity. Many organisms could not, in the process of evolution, gradually form (due to mutations) the advantages that they possess at this 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 information complexity of chromosomes and, as a consequence, DNA molecules. Such an ordered and long chain could not have been obtained by chance even over billions of billions of years. Moreover, given the enormous age of the Earth and the discovered fossils dating from very different periods, a sufficient number of missing links, transitional forms of life, which the theory of evolution assumes in large quantities among all species, have not been discovered.

The question of origin is most closely related to man’s place in the system of the organic world and his role. Perhaps it is the social component of people’s lives that is decisive. It imposes on humanity responsibility for the entire biosphere. The role and place of man in the system of the organic world was given to him for a reason - to protect and wisely manage the planet, regardless of whether people are part of the ecosystem, or are simply similar to other biological organisms, but have a higher origin and purpose of existence.

Man appeared on Earth as a result of a long process of historical and evolutionary development - phylogeny and is closely related by its origin to the animal world.

However, man differs from animals not only in his more perfect structure, but also in his developed thinking, the presence of articulate speech, and intelligence, which are determined by a complex of social conditions of life, social relationships, and socio-historical experience. Work and the social environment have changed the biological characteristics of humans.

In the system of the animal world, man occupies the following position: kingdom - Animals, type - Chordata, subtype - Vertebrates, class - Mammals, order - Primates, suborder - Anthropoids, section - Narrow-nosed, superfamily - Hominoids, family - Hominids, genus - Humans, species – Homo sapiens.

The human body has the following distinctive features that are characteristic of all representatives of the class of mammals.

1. Seven cervical vertebrae and the articulation of the skull with the first cervical vertebra using the condyles of the occipital bone.

2. The thoraco-abdominal barrier (diaphragm), built from muscle tissue and separating the chest cavity from the abdominal cavity.

3. Two generations of teeth - milk and permanent, divided into incisors, canines and molars.

4. The presence of shaped lips and muscular cheeks.

5. A four-chambered heart that ensures the delivery of arterial blood to the tissues, which does not mix with venous blood.

6. Preservation of one (left) aortic arch, whereas amphibians and reptiles have two (right and left) aortic arches.

7. Development of the outer ear and the presence of three auditory ossicles in the middle ear cavity.

8. The skin is covered with hair (for some, only during the uterine period of development), and is rich in sweat and sebaceous glands.

9. Presence of mammary glands.

In addition to the listed structural features, humans have a number of biological features similar to mammals. Thus, the human body has a constant temperature close to 37 °C. Humans are characterized by viviparity, prolonged gestation of the fetus in the mother's body and the development of special organs to perform these functions.

Humans are most similar to primates. Primates are animals with a five-fingered grasping limb. They are able to grasp objects, which is ensured by increased mobility of the fingers and the ability of the thumb to oppose the rest.

Greater mobility of the upper limb is associated with the development of the clavicle and the structural features of the spherical shoulder joint. Primate fingers have flat nails rather than claws. Primates are plantigrade animals. When moving, they rest on the entire foot. Primates have well-developed cerebral hemispheres.

They are characterized by low fertility, care for offspring, high development of herd relations, rich facial and sound signaling.

Humans and anthropomorphic (humanoid) apes (chimpanzees, gorilla, orangutans, gibbons) form the superfamily of the higher narrow-nosed animals, or hominoids. The most important features of the similarity of anthropomorphic monkeys with humans are manifested in the proportions of the body: a short body and long limbs, a set of features associated with upright posture: reduction of the caudal vertebrae, a decrease in the number of thoracic and lumbar vertebrae, an increase in the number of sacral vertebrae, the presence of rudiments of bending of the spinal column, a wide sternum and etc.

Humans and anthropomorphic monkeys are similar in cytological and biochemical characteristics. Thus, the double set (diploid number) of chromosomes in the nuclei of somatic cells in higher anthropomorphic primates and in humans is almost the same (48 chromosomes in primates, 46 in humans). Homology between humans and chimpanzees has been established in blood groups and the Rh factor, which was first discovered in monkeys.

At the same time, humans, unlike higher apes, have a number of characteristic features (signs of “hominization”).

1. Upright posture associated with transformations in the musculoskeletal system.

2. Intensive development of the brain, especially the cerebral cortex.

3. Adaptation of the arm and especially the hand to work. The ability of the thumb to oppose the rest of the fingers, especially the little finger.

4. Changes in the dentofacial apparatus and the formation of articulate speech.

5. Restructuring of the stages of ontogenesis - increasing the duration of the intrauterine period, slowing down puberty, lengthening the period of childhood, increasing life expectancy.

It should be emphasized that in humans the properties that appeared in the great apes are most clearly expressed.

Biology. General biology. Grade 11. Basic level Sivoglazov Vladislav Ivanovich

18. The position of man in the animal world

Remember!

Name the general characteristics of representatives of the phylum Chordata; class Mammals.

Data from comparative embryology and anatomy of humans and other animals make it possible to clearly determine that, according to the criteria of zoological taxonomy, the species Homo sapiens (Homo sapiens) belongs to the kingdom Animals, subkingdom Multicellular, type Chordata, subtype Vertebrates, class Mammals, order Primates, family Hominids (Fig. 58).

Rice. 58. Systematic position of humans in the order of primates

Let us consider those properties and characteristics on the basis of which we occupy this position in the system of the organic world.

Data from comparative anatomy. It is unlikely that anyone will dispute our belonging to a certain kingdom and sub-kingdom. We are bilaterally symmetrical multicellular animals and in these characteristics are similar to all worms, arthropods and chordates.

For humans, as for all representatives phylum Chordata, characterized by common organizational features that are not found in other types.

The human embryo has an internal axial skeleton that is not divided into segments - the notochord. Our nervous and digestive systems are formed in the form of two tubes lying on different sides of the notochord: the neural tube is above the notochord, and the digestive tube is below the notochord. At the early embryonic stage of development, the anterior section of the human digestive system - the pharynx - is penetrated by gill slits, which subsequently disappear, and one of them gives rise to the auditory canal and the Eustachian tube. The human circulatory system is closed, and the heart is located on the ventral side of the body.

The chordate phylum is divided into three subphyla, and the vertebrate subphylum, in turn, unites six classes. Let us list the signs that make us similar to other representatives class Mammals: bony spine replacing the notochord; seven cervical vertebrae; two pairs of lever-type limbs; presence of bone marrow (birds have hollow bones); hairline; sweat and sebaceous glands of the skin; mammary gland; well developed lips and muscular cheeks; diaphragm; three auditory ossicles of the middle ear (in birds and reptiles - one); Auricle; four-chambered heart, two circles of blood circulation and one left aortic arch; anucleate erythrocytes (in all other classes of vertebrates - nuclear); alveolar lungs. In addition to these morphological characteristics, it should be noted that all mammals, including humans, are characterized by such progressive organizational features as the high development of the central nervous system, especially the cerebral cortex; diverse adaptive reactions and complex behavior; intensive metabolism and perfect thermoregulation. Intrauterine development and nutrition of the embryo through the placenta characterizes us as representatives subclass Placental. It should be noted that all of the listed morphological characteristics, common to humans and other mammals, are homologous, that is, they have the same origin.

Common characteristics of humans and other representatives order Primates are the following: a grasping type limb (the first finger of the hand is opposed to the others); the presence of a collarbone, which ensures high mobility of the arm; expanded terminal phalanges of fingers with nails; three types of teeth - incisors, canines, molars; high development of the cerebral hemispheres; reproduction throughout the year; the presence of one pair of mammary glands; the birth of usually one cub and long-term care for it; complex organization of relationships between individuals and a high level of development of higher nervous activity.

The kinship of humans with animals is also evidenced by numerous rudiments and atavisms, which are known for almost all organ systems. Rudiments– these are underdeveloped organs that have practically lost their functions in the process of evolution. Their presence indicates the relationship of humans with lower-organized vertebrates. Examples of such rudiments are the muscles of the auricle, caudal vertebrae (coccyx), remnants of the nictitating membrane of the eye, and the vermiform appendix of the cecum. Atavisms- these are characteristics that once existed in our ancestors, were later lost, but the genes responsible for their development are still preserved and, under certain conditions, cause the formation of these ancient characteristics. Vivid examples of atavisms are facial hair, external tail, extra pairs of mammary glands, and membranes between the fingers (Fig. 59).

Data from comparative embryology. In addition to the data of comparative anatomy, significant evidence of the origin of man from animals is the results of a comparative study of the ontogenesis of man and animals.

Individual development of a person, like other animals that reproduce sexually, begins with the formation of a zygote. At two weeks of age, the human embryo shows signs of fish-like ancestors: a two-chambered heart, gill slits, and a tail artery. Later, in the structure of the embryo, one can observe features inherited from amphibians: a nictitating membrane in the inner corner of the eye, swimming membranes between the fingers. A six-week-old embryo has several pairs of mammary glands, the caudal spine is formed, which is then reduced and turns into the coccyx. The smooth surface of the cerebral hemispheres and continuous hair in the human fetus indicate a relationship with primitive mammals. Thus, the main features of human embryonic development clearly determine his animal origin.

Rice. 59. Human atavisms

Similarities and differences between humans and apes. People have many common characteristics with apes, such as a large body size, the absence of a tail and cheek pouches, good development of facial muscles and a similar skull structure (Fig. 60). Chimpanzees, gorillas, and orangutans have a well-developed brain, especially its frontal lobes, and a large number of convolutions in the cerebral cortex. In addition to morphological characteristics, other data indicate our close relationship: we are similar in Rh factor and blood groups (AB0), we suffer from the same “human” diseases. Gestation for both gorillas and humans is about 280 days.

Rice. 60. Apes

The evolutionary relatedness of organisms can be determined by comparing their chromosomes. The greater the similarity between DNA nucleotide sequences, the closer the relationship between species. Humans and chimpanzees share more than 95% of their genes.

Apes, like humans, have a high level of development of higher nervous activity, they learn easily, they have excellent memory and a rich emotional life.

At the same time, there are fundamental differences between humans and higher primates. Only humans have true upright posture (Fig. 61). Thanks to this, a person has long and powerful legs, arched feet, a wide pelvis, and an S-shaped spine. The flexible hand and movable fingers provide precise and varied movements.

A person has a complex brain, the average volume of which is 1350 cm 3 (for a gorilla 400 cm 3). Thanks to the development of the structures of the larynx, a person is capable of articulate speech.

Man is a biosocial being, occupying a high level of evolutionary development, possessing consciousness, speech, abstract thinking and capable of social work.

Rice. 61. Monkey and human skeletons

Review questions and assignments

1. Describe the systematic position of man in the animal world.

2. Indicate the characteristics of humans as a representative of the class of mammals.

3. What characteristics are common to humans and apes?

4. List the structural features inherent only to humans.

5. What was the significance of an increase in brain volume in anthropogenesis?

Think! Do it!

1. In the early period of development, the heart of the human embryo consists of one atrium and one ventricle. Please comment on this fact.

2. Remember from the zoology course and name the main characteristics of the Vertebrate subtype. What other two subtypes are distinguished in the phylum chordates? Who are their representatives? What are the features of their structure?

3. Some species of mammals actively guard and aggressively defend their territory and the territory of their pack; This is not typical for other species. Which group does a person belong to and how did this influence (and influence) the development of human society?

4. By creating tools and improving various skills, a person expands the capabilities of his body. From this point of view, discuss the role that fire and clothing, the lever and the wheel, drawings and writing played in the development of man.

5. Distribute the characteristic features unique to humans into three groups: signs associated with upright posture, with work activity and with a social way of life.

6. Complete the practical work “Observation of physiological rudiments.” Watch a person walk. If his arms are free, then when walking they will move in the same rhythm as his legs, making swinging movements along the body. For most people, a step with the left foot is accompanied by a forward movement of the right hand and vice versa. Try walking with your arms close to your body. What sensations do you experience? How comfortable are you walking? Make the task more difficult: try to simultaneously step with your left leg while throwing your left arm forward. Is it convenient for you to go? During this simple task you were introduced to the so-called friendly movements. In most cases, friendly movements are the rudiments of once expedient joint and harmonious movements. For example, hand movements when walking have been preserved in humans since the times when our distant ancestors walked on four limbs.

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Chromosomes of humans and great apes. All members of the hominid family have 24 pairs of chromosomes. The exception is people who have only 23 pairs of chromosomes. The study of the nucleotide sequence of chromosomes, their structural features, the location of constrictions, etc., allowed us to come to the conclusion that the human 2nd chromosome is the result of the fusion of two ancestral chromosomes.

The closest relative of humans, the bonobo chimpanzee, has DNA sequences almost identical to those found on human chromosome 2, but they are located on two separate chromosomes. The same thing was found in the chromosome set of more distant relatives: the gorilla and the orangutan. There is another compelling argument in favor of this point of view. Usually a chromosome has only one centromere, but on the long arm of the 2nd chromosome there are remnants of a second centromere.

Thus, the structural features of the 2nd chromosome are convincing evidence of the evolutionary origin of humans and other apes from a common ancestor.