The origin of man, stages of his formation, table. Main stages of human evolution

Human evolution has always interested people. They have been studying the theory for many decades and even hundreds of years. There are many assumptions about this. The most popular version is considered to be the one that describes the stages of human evolution from anthropoid apes.

Even in ancient times, two points of view appeared regarding this issue. The first theory is called abiogenesis. She claims that there is a possibility of the emergence of living things from non-living things. Another theory implies the impossibility of the independent origin of life. Other options also appeared: for example, the creation of life on Earth by God. Let's take a closer look at the main stages of human evolution.

A man has long tried to study his ancestry. This is reflected in legends, tales, epics of almost all tribes and nationalities.

Only in 1859 a book by Charles Darwin was published, which described it in connection with natural selection. It created a sensation and aroused great interest. Many condemned his theory, criticized and ridiculed him. But people close to science admired this creation.

This book described the natural origins of man. There was also evidence based on scientific knowledge. They talked about the connection between humans and mammals on genetic level. Over time, Darwin gained followers who began to study the stages of human evolution.

Humans and some vertebrates have common structural features. For example, features of the nervous system, skeleton, digestion, respiration and circulation. The relationship is most clearly manifested when considering the development of the embryo.

Special features are rudiments and atavisms. They are present in the human body in large quantities, but are useless. This is the heritage left over from animal ancestors. If we consider a person from the point of view of biology, then this is a mammal from the suborder of the higher, belonging to primates. However, people are rational beings. The greatest similarity is seen in people with apes, the difference between which is the ability to work and use tools.

The stages of human evolution include a period when there was a natural selection of individuals capable of activity with the use of tools. Then there was a transition from application to production of objects of labor. This was natural selection occurring as a result of evolution. Eating food cooked using fire reduced the burden on the digestive system. Gradually she underwent some changes (the intestines became shorter).

There are three stages of human evolution.

1. The appearance of the genus Homo, the first creature of which was Australopithecus. This is the stage of the biological revolution.

2. Next comes the next stage of evolution of this genus. It lasts before it begins modern stage human evolution. Here this process was influenced not only by biological factors, but also by social ones. Among the representatives of this time one can distinguish Pithecanthropus, Sinanthropus and Neanderthals.

3. The last stage is considered to be evolution. Here the greatest influence comes from social aspects existence.

The first traces of human activity with the use of tools were found in the period 2.5 - 2.8 million years ago. It is also known that many human populations did not succeed each other as a result of evolution. They existed simultaneously and disappeared as a result of the struggle for survival.

A person is something that has both biological and social characteristics. This is what distinguishes it from other creatures living on the planet.

Family tree of primates. It shows that the first of the primates to separate from the line leading to humans were gibbons, the second were orangutans, then gorillas, and only then chimpanzees - our closest relatives.

About six million years ago, chimpanzees and hominids diverged, among which, apparently, there were several dead-end branches.

The origin of man is one of the most difficult problems modern science. How did it arise, what conditions contributed to it, when and where did it happen? The answer to the first question basically already exists: thanks to paleontological finds, most of the human ancestry line has been reconstructed. Quite a few hypotheses have emerged that answer the remaining questions, but they are all controversial to some extent. Some of them are cited in his article “Chronology of Human Evolutionary History” published in the third issue of the journal “Advances in Modern Biology” in 2000 by candidate of biological sciences E. Ya. Tetushkin, an employee of the N. I. Vavilov Institute of General Genetics of the Russian Academy of Sciences.

Most modern researchers believe that the division of primates into modern bands began approximately 63 million years ago, when an asteroid fell on Earth and catastrophic destruction of the biosphere occurred. It was then that many animals became extinct, freeing up many ecological niches, which gradually began to be filled by mammals.

Most effective way Anthropological research has turned out to be molecular genetics, which today provides larger, more accurate and effective information than paleontological excavations and the study of museum specimens.

Even in ancient times, people noticed that monkeys are very similar to us, and the famous Roman physician and naturalist of the 2nd century AD who anatomized a fair number of them. e. Galen concluded that they were simply "ridiculous copies" of humans. Modern research proved he was right to a greater extent than could have been expected: monkeys are similar to humans not only externally and anatomically, but also at the DNA level, where information is transmitted precisely by copying.

IN last years scientists from many scientific centers around the world, including the Institute of Molecular Genetics Russian Academy Sciences are comparing the genomes of Homo sapiens with the genomes of other primates. It has been established that the genomes of humans and their closest relatives, the great apes, differ very little and are inaccurate, modified copies of the same original source.

Our closest kinship connects us with the African apes - chimpanzees and gorillas: in DNA they are closer to humans than to their Asian relatives - orangutans and gibbons. And the difference between the genomes of humans and chimpanzees is only 1.5%. Based on the research results, there were even proposals to rename the species Pan troglodites (common chimpanzee) to Homo troglodites. And in any case, it can be argued that it was chimpanzees that were the last to branch off from the line leading to humans.

As for humans themselves, all of their species are descendants of Australopithecus, from which the Homo line branched off about 2 million years ago. This was Homo habilis (a skilled man): he knew how to make the simplest stone tools, and his brain volume was 700-800 cm 3, whereas in Australopithecus it did not exceed 500 cm 3.

The second species of Homo, Homo erectus, appeared just when Homo habilis disappeared, that is, about one and a half million years ago. People of this species already knew how not only to improve stone tools, but also to maintain fire, and their brain volume reached 1300 cm 3. But their skull was still different from the skull modern man complete absence of chin.

The first representatives of the species Homo sapiens (archaic Homo sapiens) appeared more than half a million years ago and for a long time remained contemporaries of Homo erectus, which became extinct only a quarter of a million years ago.

However, the evolution of Homo sapiens itself was long and quite complex. The oldest remains found in Europe and Africa are 600 thousand years old (Ethiopia), 700 thousand years old (Algeria) and 500 thousand years old (England and Germany). And about 200 thousand years ago, local varieties of Homo sapiens appeared on these continents, of which the most famous is the European one - Homo sapiens neandertalis. Physically they were significantly different from their contemporaries in Africa and East Asia, which, apparently, was determined by long adaptation to the harsh climate ice age. The evolution of the predecessors of Neanderthal man most likely took place in Europe: it was there that links were discovered linking him with the earliest representatives of Homo sapiens intermediate forms- the so-called “pre-Neanderthals”. And about 120 thousand years ago - during the interglacial period - Neanderthals also conquered the Middle East and Central Asia.

And yet, the ancestor of our subspecies - Homo sapiens sapiens - was not them, but the late Homo sapiens who lived in Africa and the Middle East, and this happened, judging by the bone remains, about 100 thousand years ago. And then, according to most scientists, modern man gradually settled throughout the Ecumene.

Moreover: there is reason to believe that the universal foremother Eve mentioned in the Bible could actually exist. Molecular geneticists came to this conclusion based on comparative analysis mitochondrial DNA (mtDNA) in many people. This small ring molecule is passed down exclusively through the maternal line. Research has shown that all identified types of human mtDNA come from the same ancestral molecule, and therefore from the same foremother, who lived before the division of man into the main races.

But when, where and how did this division occur? The most convincing answers to these questions were provided by the study of the variability of proteins and blood groups. Apparently, the common ancestors of the Mongoloids and Caucasoids lived in Western Asia: it was from there that in one of the two nearest interglacial periods (that is, 70 or 50 thousand years ago), the ancestors of the Mongoloids moved to China. As for the Mongoloids of Southeast Asia and the American Indians, they are descendants of immigrants from Central and East Asia. The ancestors of Caucasians ended up in Europe only about 40 thousand years ago. They had not been able to penetrate it before: this was prevented by the “indigenous Europeans” - the Neanderthals.

Of particular difficulty is the problem of the origin of Australians and Papuans, who in their appearance are in many ways similar to Africans. The author of the article considers the most substantiated hypothesis according to which two human flows met in Southeast Asia: one came from the north - from East Asia, the other from the west - through the Indian subcontinent. When gene pools mixed, African genes were preserved and then supported by natural selection in tropical conditions.

Another hypothesis completely rejects the concept of race for a number of reasons. Firstly, not all human populations can be classified as one of the large races: many are of mixed origin. Secondly, because the very number of races identified by different anthropologists is different. And finally, thirdly, the genetic differences between people within the same race are often greater than the average genetic differences between representatives of different races. This hypothesis, of course, is controversial and, most importantly, very unconventional, but, apparently, it also has the right to further research.

Anthropogenesis (Greek anthropos man, génesis origin), part biological evolution, which led to the emergence of the species Homo sapiens, which separated from other hominids, anthropoid

monkeys and monkeys placental mammals. This is the process of historical and evolutionary formation of the physical type of a person, the initial development of his labor activity , speech, and society.

Stages of human evolution

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.

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 there 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 (a family of humans) belong..

Australopithecus

Australopithecines are highly developed bipedal primates that used objects of natural origin as tools (hence, Australopithecines 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 cm3 - 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

Without having a narrow specialization 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 cm3 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, so, apparently, at this time the australopithecines had already learned to make fire.

This stage of hominid evolution coincides with the settlement of other colder regions by people from Africa. Withstand cold winters without working out complex species behavior or technical skills would be impossible. 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 is Pithecanthropus (Japanese man) - an ape-man who walks 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 assessment, it is a little more than 400 thousand years old. The height of Pithecanthropus was about 170 cm, the volume of the skull was 900 cm3. Somewhat later, there was Sinanthropus (Chinese man). 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.

Neoanthropes and Homo sapiens

Neanderthals were replaced by modern people - Cro-Magnons - or neoanthropes. They appeared about 50 thousand years ago (their bone remains were found in 1868 in France). Cro-Magnons form singular gender n species Homo Sapiens - Homo sapiens. Their ape-like features were completely smoothed out, there was a characteristic chin protuberance on the lower jaw, indicating their ability to articulate speech, and in the art of making various tools from stone, bone and horn, the Cro-Magnons went far ahead compared to the Neanderthals.

They tamed animals and began to master agriculture, which allowed them to get rid of hunger and obtain a variety of food. Unlike their predecessors, the evolution of Cro-Magnons took place under the great influence of social factors (team unity, mutual support, improvement of work activity, a higher level of thinking).

The emergence of Cro-Magnons is the final stage in the formation of modern man . The primitive human herd was replaced by the first tribal system, which completed the formation of human society, the further progress of which began to be determined by socio-economic laws.

18) Evidence of the origin of man from animals. Atavisms and rudiments in humans.

TO it is traditionally referred to comparative anatomical, embryological, physiological and biochemical, molecular genetic, paleontological.

1. Comparative anatomical.

The general plan of the human body structure is similar to the body structure of chordates. The skeleton consists of the same sections as those of other mammals. The body cavity is divided by the diaphragm into abdominal and thoracic sections. The nervous system is tubular type. In the middle ear there are three auditory ossicles (hammer, incus, stirrup), there are auricles and associated auricular muscles. Human skin, like other mammals, contains mammary, sebaceous and sweat glands. The circulatory system is closed, there is a four-chambered heart. Confirmation of the animal origin of man is the presence of rudiments and atavisms.

2. Embryological.

In human embryogenesis, the main stages of development characteristic of vertebrates are observed (cleavage, blastula, gastrula, etc.). In the early stages of embryonic development, the human embryo develops signs characteristic of lower vertebrates: notochord, gill slits in the pharyngeal cavity, hollow nerve tube, bilateral symmetry in the structure of the body, smooth surface of the brain. The further development of the embryo exhibits features characteristic of mammals: several pairs of nipples, the presence of hair on the surface of the body, as in all mammals (except monotremes and marsupials), the development of the baby inside the mother’s body and nutrition of the fetus through the placenta.

3. Physiological and biochemical.

In humans and apes, the structure of hemoglobin and other body proteins is very similar. There are similarities in blood groups. The blood of the pygmy chimpanzee (bonobo) of the corresponding group can be transfused to humans. Humans also have the Rh blood antigen (it was first identified in the Rhesus monkey). Apes are close to humans in terms of the duration of pregnancy and the timing of puberty.

4. Molecular genetic.

All apes have a diploid number of chromosomes 2 n = 48. In humans, 2 n = 46 (it has been established that chromosome 2 in humans is formed by the fusion of two chromosomes, homologous to those in chimpanzees). There is a high degree of homology in primary structure genes (more than 90% of human and chimpanzee genes are similar to each other).

5. Paleontological.

Numerous fossil remains have been found (individual bones, teeth, skeletal fragments, tools, etc.), which make it possible to compile an evolutionary series of ancestral forms of modern humans and explain the main directions of their evolution.

Difference between humans and animals

Hereditary changes that arose during evolution under the control of natural selection contributed to the appearance of upright posture in humans, the freeing of hands, the development and enlargement of the brain skull, and the reduction of its facial part. At the same time, humans developed a need for the systematic production of tools, which contributed to the improvement of the structure and function of the hand, brain, speech apparatus, mental activity and the emergence of speech. Significant role The development of the brain and hand was influenced by the binocular (stereoscopic) color vision that human ancestors had.

Atavisms and rudiments in humans.

Rudiments are organs that have lost their basic significance in the process of evolutionary development of the organism.

Many vestigial organs are not completely useless and perform some minor functions with the help of structures apparently intended for more complex purposes.

Atavism is the appearance in an individual of characteristics characteristic of distant ancestors, but absent in nearby ones.

The appearance of atavisms is explained by the fact that the genes responsible for this trait are preserved in the DNA, but do not function because they are suppressed by the action of other genes.

Rudiments in humans:

∙ caudal vertebrae;

∙ some humans have a vestigial tail muscle, extensor coccygis, identical to the muscles that move the tail in other mammals. It is attached to the tailbone, but since the tailbone in humans can hardly move, this muscle is useless to humans;

∙ body hair;

∙ special muscles arrectores pilorum, which in our ancestors served to “raise the fur on end” (this is useful for thermoregulation, and also helps animals look larger - to intimidate predators and competitors). In humans, contraction of these muscles results in “goose bumps,” which is unlikely to have some adaptive value;

∙ three ear muscles that allowed our ancestors to move their ears. There are people who know how to use these muscles. This helps animals with large ears determine the direction of the sound source, but in humans this ability can only be used for fun;

∙ Morgani ventricles of the larynx;

∙ vermiform appendix of the cecum (appendix). Long-term observations have shown that removal of the appendix does not have a significant effect on people’s life expectancy and health, except for the fact that after this operation people, on average, suffer from colitis slightly less often;

∙ grasping reflex in newborns (it helps baby monkeys hold on to their mother’s fur);

∙ hiccups: we inherited this reflex movement from our distant ancestors - amphibians. In a tadpole, this reflex allows a portion of water to quickly pass through the gill slits. In both humans and tadpoles, this reflex is controlled by the same part of the brain and can be suppressed by the same means (for example, inhaling carbon dioxide or straightening of the chest);

∙ lanugo: hair growth that develops in a human embryo on almost the entire body except the palms and soles of the feet, and disappears shortly before birth (premature babies are sometimes born with lanugo).

Examples of atavisms:

∙ caudal appendage in humans;

∙ continuous hair on the human body;

∙ additional pairs of mammary glands;

19 . Aging of the body. Theories of aging. Geriatrics and gerontology.

Old age is a stage individual development upon reaching which the body experiences regular changes in physical condition, appearance, emotional sphere. Senile changes become obvious and increase in the post-reproductive period of ontogenesis. However, the beginning of the decline of reproductive function or even its complete loss cannot serve as the lower limit of old age. Indeed, menopause in women, which consists in the cessation of the release of mature eggs from the ovary and, accordingly, the cessation of monthly bleeding, determines the end of the reproductive period of life. However, by the time menopause is reached, most functions and external signs are far from reaching the state characteristic of old people. On the other hand, many of the changes we associate with old age begin before the decline in reproductive function. This applies both to physical signs (greying of hair, development of farsightedness) and to the functions of various organs. For example, in men, a decrease in the release of male sex hormones by the gonads and an increase in the release of gonadotropic hormones by the pituitary gland, which is typical for an old organism, begins at about 25 years of age.

There are chronological and biological (physiological) ages.

According to the modern classification, based on the assessment of many average indicators of the state of the body, people whose chronological age has reached 60-74 years are called elderly, 75-89 years old - old, over 90 years old - centenarians. Accurate determination of biological age is complicated by the fact that individual signs of old age appear at different chronological ages and are characterized by different rates of increase. Besides, age-related changes Even a single trait is subject to significant gender and individual variations.

Let's consider such a sign as the firmness (elasticity) of the skin. In this case, the same biological age is reached by a woman at about 30 years old, and by a man at 80. That is why, first of all, women need competent and constant skin care. In order to determine biological age, which is necessary for judging the rate of aging, batteries of tests are used, conducting a combined assessment of many signs that naturally change during life.

The basis of such batteries are complex functional indicators, the state of which depends on the coordinated activity of several body systems. Simple tests are usually less informative. For example, the speed of propagation nerve impulse, which depends on the state of the nerve fiber, decreases in the age range of 20-90 years by 10%, while the vital capacity of the lungs, determined by the coordinated work of the respiratory, nervous and muscular systems, decreases by 50%.

The state of old age is achieved through changes that make up the content of the aging process. This process covers all levels of the structural organization of an individual - molecular, subcellular, cellular, tissue, organ. The overall result of numerous partial manifestations of aging at the level of the whole organism is an increasing decrease in the viability of the individual with age, a decrease in the effectiveness of adaptive, homeostatic mechanisms. It has been shown, for example, that young rats, after immersion in ice water for 3 minutes, restore their body temperature in about 1 hour. Middle-aged animals require 1.5 hours, and old ones - about 2 hours.

In general, aging leads to a progressive increase in the likelihood of death. Thus, the biological meaning of aging is that it makes the death of the organism inevitable. The latter is a universal way to limit the participation of a multicellular organism in reproduction. Without death, there would be no change of generations - one of the main conditions of the evolutionary process.

Age-related changes in the aging process do not in all cases involve a decrease in the body's adaptability. In the course of life, humans and higher vertebrates gain experience and develop the ability to avoid potentially dangerous situations. The immune system is also interesting in this regard. Although its effectiveness generally decreases after the organism reaches a state of maturity, thanks to “immunological memory” in relation to some infections, old individuals may be more protected than young ones.

HYPOTHESES EXPLAINING THE MECHANISMS OF AGING

Gerontology knows at least 500 hypotheses that explain both the root cause and the mechanisms of aging of the body. The vast majority of them have not stood the test of time and are of purely historical interest. These, in particular, include hypotheses linking aging with the consumption of a special substance of cell nuclei, the fear of death, the loss of some non-renewable substances received by the body at the time of fertilization, self-poisoning with waste products, and the toxicity of products formed under the influence of the microflora of the large intestine. Hypotheses that are of scientific value today correspond to one of two main directions.

Some authors consider aging as a stochastic process of age-related accumulation of “errors” that inevitably occur during normal life processes, as well as damage to biological mechanisms under the influence of internal (spontaneous mutations) or external (ionizing radiation) factors. Stochasticity is determined by the random nature of changes in time and location in the body. In various versions of hypotheses in this direction, the primary role is assigned to various intracellular structures, the primary damage of which determines functional disorders at the cellular, tissue and organ levels. First of all, this is the genetic apparatus of cells (hypothesis of somatic mutations). Many researchers associate the initial changes in the aging of the body with changes in the structure and, consequently, the physicochemical and biological properties of macromolecules: DNA, RNA, chromatin proteins, cytoplasmic and nuclear proteins, enzymes. Lipids are also particularly distinguished cell membranes, which are often targets for free radicals. Failures in the functioning of receptors, in particular cell membranes, disrupt the effectiveness of regulatory mechanisms, which leads to a mismatch in vital processes.

The direction under consideration also includes hypotheses that see the fundamental basis of aging in the increasing wear and tear of structures with age, ranging from macromolecules to the organism as a whole, ultimately leading to a state incompatible with life. This view, however, is too straightforward.

Let us recall that the emergence and accumulation of mutational changes in DNA are resisted by natural antimutational mechanisms, and the harmful consequences of the formation of free radicals

are reduced due to the functioning of antioxidant mechanisms. Thus, if the “concept of wear and tear” of biological structures correctly reflects the essence of aging, then the result in the form of a greater or lesser rate of senile changes in the age at which different people these changes becoming obvious are a consequence of the superposition of destructive and protective processes. In this case, the wear hypothesis inevitably includes

factors such as genetic predisposition, conditions and even lifestyle, on which, as we have seen, the rate of aging depends.

The second direction is represented by genetic or program hypotheses, according to which the aging process is under direct genetic control. This control, according to one view, is carried out using special genes. According to other views, it is associated with the presence of special genetic programs, as is the case with other stages of ontogenesis, for example embryonic.

There is evidence in favor of the programmed nature of aging, many of which have already been discussed in Section. 8.6.1. Usually they also refer to the presence in nature of species in which, following reproduction, changes rapidly increase, leading to the death of animals. A typical example is Pacific salmon (sockeye salmon, pink salmon), which die after spawning. The triggering mechanism in this case is associated with a change in the secretion regime of sex hormones, which should be considered as a feature of the genetic program of individual development of salmonids, reflecting their ecology, and not as a universal mechanism of aging.

It is noteworthy that castrated pink salmon do not spawn and live 2-3 times longer. It is during these additional years of life that we should expect signs of aging to appear in cells and tissues. Some program hypotheses are based on the assumption that a biological clock functions in the body, in accordance with which age-related changes occur. The role of the “clock” is attributed, in particular, to the thymus gland, which ceases functioning when the body enters adulthood. Another candidate is the nervous system, especially some of its parts (hypothalamus, sympathetic nervous system), the main functional element of which is primarily aging nerve cells. Let us assume that the cessation of thymus functions at a certain age, which is undoubtedly under genetic control, is a signal of the beginning of aging of the body. This, however, does not mean genetic control of the aging process. In the absence of the thymus, immunological control over autoimmune processes is weakened. But in order for these processes to take place, either mutant lymphocytes (DNA damage) or proteins with altered structure and antigenic properties are required.

Gerontology and Geriatrics

Gerontology (from the Greek gerontos - old man) is a branch of biology and medicine that studies the patterns of aging of living beings, including humans. The main areas of gerontology include the study of the main causes, mechanisms and conditions of aging, the search for effective means of increasing life expectancy and extending the period of active working capacity.

Geriatrics (from the Greek iatreia - treatment) is a field of clinical medicine that studies the diagnosis, treatment and prevention of diseases of elderly and senile people.

The position of man in the animal world

Anthropology is the science of human origins.

2. Fill out the table

Development of views on human origins

3. What is the main evidence for the origin of humans from animals?
Data from comparative anatomy and embryology show similarities in the body structure and development of humans and animals.
Traits inherent in chordates:
In humans, in the early stages of development, the internal skeleton is represented by a chord, the neural tube is laid on the dorsal side, the body has bilateral symmetry. Next, the notochord is replaced by the spinal column, the skull and five sections of the brain are formed. The heart is on the ventral side of the body, there is a skeleton of paired free limbs.
Traits inherent in the class Mammals:
There are five sections of the spine, the skin is covered with hair, there are sweat and sebaceous glands. Feeding children with milk, four-chambered heart, warm-bloodedness, diaphragm.
Traits inherent to Placentals:
Carrying a fetus inside the body, feeding the fetus through the placenta.
The main features of the order Primates:
The structure of the limbs, nails, eyes in one plane, replacement of milk teeth with permanent ones.
Similar features to great apes. The presence of atavisms (features of ancestral forms that appeared in individual individuals of a given species) - this is a tail, multiple nipples, abundant hair, etc. and rudiments (organs or parts of the body that have lost their original functions in the process of evolution and are present in all individuals of a given biological species) – this is the appendix, wisdom teeth, etc.

4. Describe the position of man in the system of the organic world.
Kingdom Animals, Subkingdom Multicellular, phylum Chordata, subtype Vertebrates, class Mammals, subclass Placentals, order Primates, suborder Apes, family People (Hominids), genus Homo, species Homo sapiens, Subspecies Homo sapiens sapiens.

5. Make a table.

Similarities and differences between humans and apes.

1. Define the concept.
Anthropogenesis- part of the biological evolution that led to the emergence of Homo sapiens, which separated from other hominids, apes and placental mammals; the process of historical and evolutionary formation of a person’s physical type, the initial development of his work activity, speech.

2. What concept underlies modern scientific ideas about human origins?
The basis of modern ideas about the origin of man is the concept according to which man emerged from the animal world, and the first scientific evidence in favor of this concept was presented by Charles Darwin in his work “The Descent of Man and Sexual Selection” (1871). Scientists believe that the evolutionary line of hominids begins from some group of Dryopithecus (an extinct group of great apes).

3. What paleontological finds allow us to identify the main stages and directions historical development humans and apes?
Analysis of paleontological finds allows us to identify the main stages and directions of the historical development of humans and great apes. These include the remains of Australopithecus archanthropus (Pithecanthropus, Sinanthropus), paleoanthropus (Neanderthal), Cro-Magnon man, their tools and rock paintings. That is, humans and modern apes had a common ancestor. Further, their evolutionary development followed the path of divergence (divergence of characteristics, accumulation of differences) in connection with adaptation to specific and different conditions of existence.

4. Why can’t we say that man descended from the ape?
The development of humans and apes is not sequential steps, but parallel branches of evolution, the divergence between which in evolutionary terms is very deep. That is, humans and modern apes had a common ancestor. Further, their evolutionary development followed the path of divergence (divergence of characteristics, accumulation of differences) in connection with adaptation to specific and different conditions of existence.

5. Fill out the table.

Main stages of anthropogenesis

Driving forces of anthropogenesis

1. Define the concept.
Social evolution– the process of structural reorganization over time, as a result of which there arises social form or a structure that is qualitatively different from the previous form.

2. Make a diagram.

Factors of anthropogenesis.

3. What is the role of biological and social factors in anthropogenesis?
In anthropogenesis, an important role is played not only by biological factors (variability, heredity, selection), but also by social ones (speech, accumulated experience of work and social behavior). Human characteristics, determined by social factors, are not fixed genetically and are not inherited, but in the process of upbringing and training. In the first stages of evolution, selection for greater adaptability to rapidly changing circumstances was of decisive importance. However, subsequently, the ability to transmit genetic acquisitions from generation to generation in the form of various scientific, technical and cultural information began to play an increasingly important role, freeing humans from the strict control of natural selection. Social patterns have acquired great importance in human evolution. The winners in the struggle for existence were not necessarily the strongest, but those who preserved the weak: children - the future of the population, old people - keepers of information about ways to survive. The victory of populations in the struggle for existence was ensured not only by strength and intelligence, but also by the ability to sacrifice themselves in the name of the tribe. Man is a social being distinctive feature which is consciousness formed on the basis of collective labor.
In the evolution of Homo sapiens, social relationships play an ever-increasing role. For modern people, social-labor relations have become leading and determining. This is the qualitative uniqueness of human evolution.

4. What modern problems human society can you name?
People are increasingly using surrogates and imitations of natural biological activity, going so far as to “virtualize” life. The human population is characterized by phenomena that are impossible for animal populations. In the human population, the genetic load of hereditary diseases accumulates, predisposition to diseases, malignant neoplasms, infections, mental and allergic disorders, maladjustment phenomena, etc. Residents of large cities experience overcrowding stress phenomena. Many people maintain their existence and functionality only with the help of artificial devices and medications.
Rapid population growth creates economic problems and increases social inequality among people. There is a growing gap between the maximum opportunities for obtaining benefits and their accessibility for the majority of people. Different people have very unequal life chances.
Products are stimulated and produced that are not only unnecessary for human life, but also cause harm (alcohol, tobacco, drugs).
All these factors as a whole can ultimately lead to a crisis of modern human civilization, degradation and extinction of Homo sapiens as a species.

5. What factors contributed to the development of upright walking in humans?
There are a number of hypotheses regarding the development of upright walking in humans. The appearance of an S-shaped spine, an arched foot, an expanded pelvis, and a strong sacrum in human ancestors are hereditary changes that contributed to upright walking.
According to Jan Lindblad's hypothesis, the ape-like ancestors of humans were forced to rise on their hind limbs when searching for food in the water and when wading through water obstacles. Also, due to climate and flora changes, human ancestors were forced to get down from the trees to the ground. To search for food in the tall grass, they had to stand up from all fours onto their hind limbs.

6. What advantages and what problems, including health problems, have people experienced due to upright walking?
Individuals capable of walking on their hind limbs found themselves in a more advantageous position. The horizons expanded, hands were freed, with the help of which human ancestors were able to use improvised means - sticks and stones, and subsequently - to make the tools themselves.
Disadvantages of upright walking include loss of speed, heavy load on the legs, spine. Also, there was an incorrect distribution of blood volume between the lower and upper halves of the body. In this case, the lower extremities are constantly in a state of hypertension, while the upper extremities are in hypotension.
The vertical position of the human body leads to indigestion and back pain, varicose veins and other disorders of its vital functions. The same reason makes pregnancy and childbirth extremely difficult and delays.

7. Is it possible to say that the biological evolution of modern man has completely stopped?
Evolution- a continuous process, therefore, even for the species Homo sapiens, it did not stop. Evolution has moved to another level. A person adapts to new living conditions, physical labor becomes less important and widespread. Due to the weakening biological factors and the increase in social life, a person will be subject to changes, both external and internal, what exactly is a matter of time, the answer to which scientists are already looking for today.

Origin of human races

1. Give definitions of concepts.
Human races– historically established groupings of people within the species Homo sapiens sapiens, characterized by similar morphological and physiological traits.
Racism– anti-scientific ideology about the inequality of human races.

2. Look at the drawing “Races of Man.” Label it with the names of the races you know.
Australian-Negroid, Caucasoid, Mongoloid.

3. What hypotheses of raceogenesis do you know?
Raceogenesis is the process of the emergence and formation of human races. There are several hypotheses of raceogenesis.
The first is monocentrism. Scientists recognize a common origin, socio-psychological development, and a single level of mental development. Evidence of the monocentric hypothesis transfers it to the category of theories (hypothesis + evidence):
differences in secondary characteristics;
there is no genetic isolation;
biological evolutionary changes (decrease in skeletal mass, increase in height, acceleration of development) appear in representatives of all races;
results obtained from studying human DNA: the first was the division of the African branch into Negroid and Mongoloid-Caucasian about 40-100 thousand years ago.
Polycentricists believe that races arose independently from different ancestors and in different places. Their hypothesis is less scientifically substantiated.

4. What are the main factors of raceogenesis?
Natural selection;
Mutations;
Insulation;
Mixing of populations.
As people settle globe When faced with new environmental conditions, adapted individuals survived and gave birth to offspring. The morphological characteristics formed during biological evolution are explained:
the nature of the environment;
climate;
food resources;
amount of sunlight.

5. Fill out the table.

Human races

6. What arguments can be made to criticize racist theories?
People of all races are characterized by specific characteristics:
similarity in body structure (structure of the skull, brain, internal organs);
physiological similarity (blood types, diseases, defense reactions);
the possibility of unlimited crossing, which results in fertile offspring;
all are of the same origin.
It is impossible to accurately determine a person’s race based on a person’s genes, therefore, in the genetic sense, races do not exist (only traits, dominant and recessive, different norms of behavior). Racial differences are the result of people's adaptation to certain conditions of existence, as well as the historical and socio-economic development of human society.

Target: consider the directions of human evolution, the multifaceted role of natural selection in populations of ancient people; show that labor has caused changes in the physical type and psychological make-up of a person; highlight the educational significance of a person above himself.

Lesson type: lecture using presentation.

Equipment: tables “Human Evolution”, collections “Human Evolution”, computer, projector, lesson presentation (Appendix 1).

During the classes

I. Organizational moment

II. Learning new material

1. The study of modern and fossil primates provides material that allows us to understand how the characteristic features of man arose that took him beyond the animal world. The common ancestor of humans and apes was one of the branches of the narrow-nosed apes. The most ancient representatives of this branch moved along the ground on their hind limbs, assisted by their forelimbs. The movements of the forelimbs became more free and varied, and the relationship between all the organs of the animal changed.

The following were important: herd lifestyle, communication with each other, caring for offspring. A high level of development of the brain and psyche, the use of natural objects as tools for hunting and protection from enemies have become the most important prerequisites for humanization, the basis for the development of thinking and work activity (slide 1 - 3).

2. Australopithecus(“Australos” - southern, “pithecus” - monkey) lived in open forest-steppe spaces about 5.5 million years ago. They walked on their hind limbs and had a well-developed thumb. Australopithecines did not have such natural defenses as great physical strength, powerful jaws, sharp claws, and did not have the advantage of fast running. The use of natural objects (stones, long bones of large animals) as tools that replaced the organs of defense and attack allowed Australopithecines to overcome their defenselessness in conditions where it was difficult to hide from enemies.

Over time, some groups of australopithecus gradually began to move to making tools from volcanic lava, quartzite and especially silicon. However, man did not arise immediately after the emergence of labor activity, but as a result of his long formation and development. The Australopithecus stage helps restore one of the most important moments in evolution - the beginning of the transformation of animals into humans (slide 4).

3. The earliest people

It is believed that the earliest people arose about 1 million years ago. Several forms of ancient people are known: Pithecanthropus, Sinanthropus, Heidelberg Man, etc.

Pithecanthropus(ape-men) lived in a hot tropical climate. They walked on their hind legs, perhaps leaning on a club. They were about 170 cm tall. Skull structure: the brain part is small, brain volume up to 1100 cm 3; massive lower jaw with sloping chin; there is a supraorbital ridge on the forehead. They made primitive stone tools (scrapers, choppers). Along with obtaining plant food, hunting plays an important role. They used fire. They communicated with gestures and sounds, led a herd lifestyle, and did not build dwellings.

Remains were found in the Zhou-Gou-Dian cave not far from Beijing. Sinanthropa(Chinese man), close in many characteristics to human Pithecanthropus (slide 5). In synanthropes, the brain volume reached up to 1200 cm 3; the left lobe of the brain is more developed than the right, which, apparently, is associated, like in modern humans, with right-handedness (demonstration of the cerebral part of the skull)

The ability to use fire was a great achievement of man. It made food more digestible, contributed to better protection from enemies and cold, and expanded the range of ancient people.

Thinking (in a primitive form), the use of fire, and the manufacture of tools became the main advantages of ancient people in the struggle for existence. At this stage of evolution, new social patterns in the existence of human society begin to appear.

4. Ancient people who are called Neanderthals, replaced the most ancient people (slide 6). They appeared about 150 thousand years ago. Neanderthals lived in the harsh conditions of glaciated Europe. Their height reached 156 cm. Skull structure: low sloping forehead, continuous supraorbital ridge, poorly developed chin protuberance; the volume of the brain was up to 1400 cm3. Neanderthals communicated with gestures and sounds; development of rudimentary speech occurred (demonstration of the skull).

Ancient people knew how to make and maintain fire, and made tools from wood and stone. With the help of manufactured tools, ancient people hunted, skinned animals, butchered carcasses (demonstration of replicas of tools).

Neanderthals settled in caves of 50 - 100 people, which they often had to conquer from cave bears and hyenas. The cave, in which the fire burned, reliably protected from the cold and from attacks by predatory animals.

Ancient people noted the emergence of elementary social relationships, which were expressed in caring for those who, due to wounds or illnesses, could not obtain food on their own. Burials are found for the first time among Neanderthals. Collective actions already played a decisive role in the primitive herd of ancient people. In the struggle for existence, those groups that successfully hunted and better provided themselves with food, took care of each other, achieved lower mortality among children and adults, and better overcome difficult living conditions won. The ability to make tools, articulate speech, the ability to learn - these qualities turned out to be useful for the team as a whole. Natural selection ensured the further progressive development of many traits. As a result, the biological organization of people also improved. This evolutionary path led to the appearance of the Homo sapiens species 40 thousand years ago. For some time, Neanderthals and the first modern people coexisted, but about 28 thousand years ago, the Neanderthals were finally supplanted by the first modern people - the Cro-Magnons.

5. The first modern people are Cro-Magnons– they were tall - up to 180 cm, with a high forehead, brain volume 1600 cm 3 (slide 7). There was no continuous ridge above the eyes; the chin protuberance is well developed on the lower jaw, which indicates the development of articulate speech. The Cro-Magnons had the entire complex of basic physical features that our contemporaries also have. Their mental development has reached high level. This is evidenced by the changes that have taken place in their lives.

Flint tools became more diverse and sophisticated; the Cro-Magnons began to widely use materials that were difficult to process: bone, horn. They knew how to drill, grind, knew pottery, tamed animals, began to develop agriculture, sewed animal skins and made clothes and housing from them. All this made people less dependent on climatic conditions. That is why people began to explore previously inaccessible areas of the globe. Cro-Magnons live in tribal communities in built dwellings. At this stage, another major event occurred in people’s lives - the emergence of art. Drawings by the first artists discovered on the walls of caves, stone and bone sculptures made with amazing skill for that time. The painting of the Kapova Cave (in the Urals) is world famous. Religion is born. Human evolution has escaped the dominant control of biological facts and acquired a social character.

6. Generalization about the stages of anthropogenesis(slide 8 - 9).

Labor caused changes in a person’s physical type and mental make-up. Influencing environment in the process of labor, man changed it and changed himself, distinguishing himself in nature. The historical process of formation of people's consciousness is reflected in the development of each person. Each person, despite the presence of “human” development opportunities, must show great determination, perseverance and ability to work in possessing the rich experience of humanity - knowledge and skills.

III. Homework: § 5.2 p. 197 – 202;