The doctrine of evolution is the theoretical basis of biology. It studies the causes and mechanisms of the historical development of all living organisms. Human evolution has its own characteristics and factors.

What is anthropology

According to evolutionary theory, man was formed over a long period of time. The processes of its historical development are studied by the science of anthropology.

The emergence of man has its own characteristic features. They lie in the fact that the process of formation is influenced by both social and biological factors. The first group includes the ability to work, speech. The biological factor in human evolution is, in particular, the struggle for existence. As well as natural selection and hereditary variability.

Basic provisions of evolutionary theory

According to Charles Darwin's theory, environmental conditions can cause changes in the structure of living organisms. If they are not inherited, then their role in the process of evolution is insignificant. In some individuals, changes occur in the germ cells. In this case, the trait is inherited. If it proves useful under certain conditions, then the organisms have a better chance of survival. They adapt successfully and produce fertile offspring.

Struggle for existence

The main biological factor in human evolution is its essence in the emergence of competition between organisms. The reason for its appearance is the discrepancy between the ability of different species to feed and reproduce. As a result, the species that was able to best adapt to specific conditions survives.

Despite the fact that the process of the emergence of modern man was subject to general laws, there are a number of differences. Natural selection occurred not only for strength, agility and endurance. In addition to these physical characteristics, the level of mental development also played a special role. Individuals who learned to make and use the most primitive tools, communicate with fellow tribe members, and act together had a greater chance of survival.

Natural selection

During the struggle for existence, natural selection occurs - a biological process during which adapted individuals survive and actively reproduce. Those who fail to adapt die.

Thus, natural selection is also a biological factor in human evolution. Its peculiarity was that individuals with pronounced social traits survived. The most viable people turned out to be those who invented new tools, acquired new skills and socialized. Over time, the importance of natural selection in the process of anthropogenesis decreased. This is due to the fact that ancient people gradually learned to build, improve and heat homes, make clothes, grow plants, and domesticate animals. As a result, the importance of natural selection gradually decreased.

Hereditary variability

Hereditary variability is also a biological factor in human evolution. This property of living organisms lies in the ability to acquire new characteristics in the process of their development and pass them on by inheritance. Naturally, only useful traits had evolutionary significance in the process of anthropogenesis.

Humans are similar to mammals by a number of similar biological traits. This is the presence of mammary and sweat glands, hair, and viviparity. The body cavity is divided by a muscular septum, the diaphragm, into thoracic and abdominal parts. Similar signs are the absence of nuclei in red blood cells, erythrocytes, the presence of alveoli in the lungs, the general plan of the structure of the skeleton, differentiated teeth. Both humans and animals have rudimentary (underdeveloped) organs. These include the appendix, the third eyelid, the rudiments of the second row of teeth and others. Scientists know cases of people being born with the characteristic features of animals - a developed tail, continuous hair, an additional number of nipples. This provides additional evidence from animals. But in the process of anthropogenesis, only the most useful features were preserved.

The following biological traits are specific only to humans:

Upright walking;

Enlargement of the brain and reduction of the facial part of the skull;

Arched foot with strongly developed big toe;

Movable hand, thumb opposed to the rest;

Increase in brain volume, development of its cortex.

Human biological evolution is closely related to social evolution. For example, the ability to make fire and cook food led to a decrease in the size of teeth and the length of the intestines.

Biological factors of human evolution are a necessary condition for the formation of social ones, which together led to the appearance of Homo sapiens on Earth.

The main trends in human development were upright walking, an increase in the volume of the brain and the complication of its organization, the development of the hand, and an extension of the period of growth and development. A developed hand with a well-defined grasping function allowed a person to successfully use and then make tools. This gave him advantages in the struggle for existence, although in terms of his purely physical qualities he was significantly inferior to animals. The most important milestone in human development was the acquisition of the ability to first use and maintain, and then produce fire. The complex activity of making tools, making and maintaining fire could not be achieved by innate behavior, but required individual behavior. Therefore, the need arose to significantly expand the possibility of exchanging signals and a speech factor appeared, which fundamentally distinguishes humans from other animals. The emergence of new functions, in turn, contributes to accelerated development. Thus, the use of hands for hunting and protection and feeding on food softened over fire made the presence of powerful jaws unnecessary, which made it possible to increase the volume of the brain part of the skull at the expense of its facial part and ensure the further development of human mental abilities. The emergence of speech contributed to the development of a more advanced structure of society, the division of responsibilities between its members, which also provided advantages in the struggle for existence. Thus, the factors of anthropogenesis can be divided into biological and social.

Biological factors - hereditary variability, the struggle for existence, natural selection, as well as the mutation process, isolation - are applicable to human evolution. Under their influence, in the process of biological evolution, morphological changes occurred in the ape-like ancestor - anthropomorphosis. The decisive step on the path from ape to man was upright walking. This led to the release of the hand from the functions of movement. The hand begins to be used to perform a variety of functions - grasping, holding, throwing.

No less important prerequisites for anthropogenesis were the biological features of human ancestors: a herd lifestyle, an increase in brain volume in relation to the general proportions of the body, binocular vision.

Social factors of anthropogenesis include work activity, social lifestyle, development of speech and thinking. Social factors began to play a leading role in anthropogenesis. However, the life of each individual is subject to biological laws: mutations persist as a source of genotypic variability, and stabilizing selection acts, eliminating sharp deviations from the norm.

Factors of anthropogenesis

1) Biological

• natural selection amid the struggle for existence
• genetic drift
• insulation
• hereditary variability

2) Social

• public life
• consciousness
• speech
• work activity

At the first stages of human evolution, biological factors played a dominant role, and at the last - social ones. Labor, speech, and consciousness are closely connected with each other. In the process of labor, there was a unification of members of society and the rapid development of a method of communication between them, which is speech.

The common ancestors of humans and apes - small arboreal insectivorous placental mammals - lived in the Mesozoic. In the Paleogene of the Cenozoic era, a branch separated from them, leading to the ancestors of modern apes - Parapithecus.

Parapithecus -> Dryopithecus -> Australopithecus -> Pithecanthropus -> Sinanthropus -> Neanderthal -> Cro-Magnon -> modern man.

Analysis of paleontological finds allows us to identify the main stages and directions of the historical development of humans and great apes. Modern science gives the following answer: 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.

Human ancestry

Insectivorous mammals -> parapithecus:

1. Propliopithecus -> Gibbon, Orangutan
2. Dryopithecus -> Chimpanzee, Gorilla, Australopithecus -> Ancient people (Pithecanthropus, Sinanthropus, Heidelberg man) -> Ancient people (Neanderthals) -> New people (Cro-Magnon, modern man)

We emphasize that the human pedigree presented above is hypothetical. Let us also recall that if the name of the ancestral form ends in “pithecus,” then we are still talking about a monkey. If there is “anthrop” at the end of the name, then we have a person in front of us. True, this does not mean that his biological organization necessarily lacks the characteristics of a monkey. It is necessary to understand that the characteristics of a person prevail in this case. From the name “pithecanthropus” it follows that this organism exhibits a combination of characteristics of a monkey and a human, and in approximately equal proportions. Let us give a brief description of some of the supposed ancestral forms of man.

Dryopithecus

Lived approximately 25 million years ago.

Characteristic features of development:

• significantly smaller than a person (height about 110 cm);
• led a predominantly arboreal lifestyle;
• probably manipulated objects;
• there are no tools.

Australopithecus

Lived approximately 9 million years ago

Characteristic features of development:

• height 150-155 cm, weight up to 70 kg;
• skull volume - about 600 cm 3;
• probably used objects as tools for obtaining food and protection;
• characterized by upright posture;
• jaws are more massive than those of humans;
• highly developed brow ridges;
• joint hunting, herd lifestyle;
• often ate the remains of predators' prey

Pithecanthropus

Lived approximately 1 million years ago

Characteristic features of development:

• height 165-170 cm;
• brain volume is about 1100 cm 3 ;
• constant upright posture; speech formation;
• mastery of fire

SYNATHROP

Lived probably 1-2 million years ago

Characteristic features of development:

• height about 150 cm;
• upright walking;
• production of primitive stone tools;
• maintaining fire;
• social lifestyle; cannibalism

NEANDERTHAL

Lived 200-500 thousand years ago

Characteristic features:

Biological:

• height 165-170 cm;
• brain volume 1200-1400 cm3;
• lower limbs are shorter than those of modern humans;
• the femur is strongly curved;
• low sloping forehead;
• highly developed brow ridges

Social:

• lived in groups of 50-100 individuals;
• used fire;
• made various tools;
• built hearths and dwellings;
• carried out the first burials of their fallen brothers;
• speech is probably more advanced than that of Pithecanthropus;
• perhaps the emergence of the first religious ideas; skilled hunters;
• cannibalism persisted

The qualitative uniqueness of human evolution lies in the fact that its driving forces were not only biological, but also social factors, and it was the latter that were decisive in the process of human formation and continue to play a leading role in the development of modern human society.

Biological factors of human evolution

Man, like any other biological species, appeared on Earth as a result of the interconnected action of factors in the evolution of the living world. How did natural selection contribute to the consolidation of those morphological characteristics of humans that distinguish them from their closest relatives among animals?

The main reasons that forced once arboreal animals to switch to life on land were a reduction in the area of ​​tropical forests, a corresponding decrease in the food supply and, as a consequence, an increase in body size. The fact is that an increase in body size is accompanied by an increase in absolute, but a decrease in relative (i.e., per unit body weight) food needs. Large animals can afford to eat less high-calorie foods. The decline of tropical forests has increased competition between monkeys. Different species took different approaches to solving the problems they faced. Some learned to run quickly on all fours and mastered open terrain (savannah). An example is baboons. Their enormous physical power allowed the gorillas to stay in the forest without any competition. Chimpanzees turned out to be the least specialized of all the great apes. They can deftly climb trees and run quite quickly on the ground. And only hominids solved the problems they faced in a unique way: they mastered walking on two legs. Why was this method of transportation beneficial for them?

One of the consequences of an increase in body size is an increase in life expectancy, which is accompanied by a lengthening of the gestation period and a slowdown in the rate of reproduction. In apes, one baby is born every 5-6 years. His death in an accident turns out to be a very costly loss for the population. Bipedal apes managed to avoid such a critical situation. Hominids learned to take care of two, three, four cubs at the same time. But this required more time, effort and attention, which the female had to devote to her offspring. She was forced to give up many other forms of activity, including searching for food. The males did this. Freeing the forelimbs from participating in locomotion allowed males to bring more food for females and cubs. In the current situation, moving on four limbs has become unnecessary. On the contrary, upright walking gave hominids a number of advantages, the most valuable of which turned out to be the ability to make tools after 2 million years.

Social factors of human evolution

The creation and use of tools increased the adaptability of ancient man. From that moment on, any hereditary changes in his body that turned out to be useful in tool activity were fixed by natural selection. The forelimbs underwent evolutionary transformation. Judging by fossils and tools, the working position of the hand, the method of grip, the position of the fingers, and force tension gradually changed. In the technology of manufacturing tools, the number of strong blows was reduced, the number of small and precise movements of the hand and fingers increased, the factor of strength began to give way to the factor of accuracy and dexterity.

The use of tools when cutting carcasses and cooking food over fire resulted in a reduction in the load on the masticatory apparatus. On the human skull, those bony protrusions to which powerful chewing muscles are attached in monkeys gradually disappeared. The skull became more rounded, the jaws became less massive, and the facial region became straightened.

A tool of labor can be made only if a mental image and a conscious goal of the work are formed in the imagination of its creator. Human labor activity helped develop the ability to reproduce in the mind coherent ideas about objects and manipulations with them.

A prerequisite for the development of speech had to be a sufficiently developed brain, which allowed a person to associate a variety of sounds and ideas. Speech owes its origin to the imitation and modification of various natural sounds (the voices of animals, the instinctive cries of man himself). The benefits of community cohesion through speech became clear. Training and imitation made speech more and more articulate and perfect.

Thus, the distinctive features of man - thinking, speech, the ability to use tools - arose in the course and on the basis of his biological development. Thanks to these features, man learned to withstand the adverse influences of the environment to such an extent that his further development began to be determined not so much by biological factors as by the ability to create perfect tools, arrange homes, obtain food, raise livestock and grow edible plants. The formation of these skills occurs through training and is possible only in the conditions of human society, i.e. in a social environment. Therefore, weapon activity, along with the social way of life, speech and thinking, are called social factors in human evolution. Children who grew up isolated from people do not know how to speak, are not capable of mental activity, or of communicating with other people. Their behavior is more reminiscent of the behavior of the animals among which they found themselves shortly after birth. The formation of man is inextricably linked with the formation of human society.

The relationship between biological and social factors in human evolution. Biological factors played a decisive role in the early stages of homind evolution. Almost all of them continue to operate at the present time. Mutation and combination-type variability support the genetic diversity of humanity. Fluctuations in the number of people during epidemics and wars randomly change the frequencies of genes in human populations. The listed factors together supply material for natural selection, which operates at all stages of human development (culling of gametes with chromosomal rearrangements, stillbirths, infertile marriages, death from disease, etc.).

The only biological factor that has lost its significance in the evolution of modern man is isolation. In the era of advanced technical means of transportation, constant migration of people has led to the fact that there are almost no genetically isolated population groups left.

Over the past 40 thousand years, the physical appearance of people has hardly changed. But this does not mean the end of human evolution as a biological species. It should be noted that 40 thousand years is only 2% of the existence of the human race. It is extremely difficult to detect human morphological changes over such a short period of time on a geological scale.
As human society developed, a special form of communication between generations arose in the form of continuity of material and spiritual culture. By analogy with the system of inheritance of genetic information, we can talk about the system of inheritance of cultural information. Their differences are as follows. Genetic information is passed on from parents to offspring. Cultural information is available to anyone. The death of a person leads to the irreversible disappearance of a unique combination of his genes. On the contrary, the experience accumulated by a person will flow into universal human culture. Finally, the speed of dissemination of cultural information is much greater than the speed of transmission of genetic information. The consequence of these differences is that modern man as a social being develops much faster than as a biological being.

In the course of evolution, man has acquired the greatest advantage. He learned to maintain harmony between his unchanging body and his changing nature. This is the qualitative uniqueness of human evolution.

Human races. In modern humanity, there are three main races: Caucasoid, Mongoloid and Equatorial (Negro Australoid). Races are large groups of people distinguished by certain external characteristics, such as skin color, eyes and hair, hair shape, facial features. The formation of racial characteristics was facilitated by the fact that human settlement on Earth 100-10 thousand years ago took place in small groups that made up a small part of the original population. This led to the fact that the newly formed isolated populations differed from each other in the concentrations of certain genes. Since the population of the Earth during this the period was very small (no more than 3 million people 15 thousand years ago), newly formed populations in different parts of the world developed in isolation from each other.

In different climatic conditions, under the influence of natural selection on the basis of different gene pools, characteristic external features of human races were formed. However, this did not lead to the formation of different species, and representatives of all races are classified as one biological species - Homo sapiens. In terms of their ability to learn, work, and creative abilities, all races are the same. Currently, racial characteristics are not adaptive. An increase in population, a sharp decrease in the level of isolation of populations, and the gradual disappearance of racial, ethnic and religious prejudices lead to the erosion of interracial differences. Apparently, in the future these differences should disappear.



Remember:

What are the factors of biological evolution?

Answer. Biological factors, or the driving forces of evolution, are common to all living nature, including humans. These include hereditary variability and natural selection.

The role of biological factors in human evolution was revealed by Charles Darwin. These factors played a big role in human evolution, especially in the early stages of its formation.

A person experiences hereditary changes that determine, for example, hair and eye color, height, and resistance to environmental factors. In the early stages of evolution, when man was heavily dependent on nature, individuals with hereditary changes that were useful in given environmental conditions (for example, individuals distinguished by endurance, physical strength, dexterity, and intelligence) predominantly survived and left offspring.

Questions after § 29

What factor was decisive in the formation of the species Homo Sapiens?

Answer. The decisive factor in the development of a person is social. Social factors of anthropogenesis include labor, social lifestyle, developed consciousness and speech. The role of social factors in anthropogenesis was revealed by Engels in his work “The Role of Labor in the Process of Transformation of Ape into Man” (1896). These factors played a leading role in the later stages of human development.

Labor activity contributed to the consolidation of morphological and physiological changes in human ancestors, which are called anthropomorphoses.

An important anthropomorphosis in human evolution was upright walking. Over many generations, as a result of natural selection, individuals with hereditary changes favoring upright walking were preserved. Adaptations for upright walking gradually developed: an S-shaped spine, an arched foot, a wide pelvis and chest, and massive bones of the lower extremities.

Which communities of ancient people were more likely to survive the selection process?

Answer. Communities of ancient people were subject to group selection, which favored the preservation of those groups in which more socially developed individuals predominated. This was expressed in the improvement of the inhibitory mechanisms of the brain, which made it possible to reduce mutual aggressiveness, as well as in the development of properties that contributed to the enrichment of knowledge based on one’s own and others’ experience.

The most important feature of human society is the presence of a fund of social and cultural information, not biologically inherited and transmitted from generation to generation through learning (and at later stages of social development, coded in writing) and in the form of tools and other material and spiritual values ​​created by previous generations. The growth and development of this social fund gradually reduced man's dependence on nature, which could not but lead to significant changes in the very nature of human evolutionary transformations. For any human population, the fund of material culture accumulated by previous generations is the most important part of the habitat. Natural selection adapted human groups to this specific environment - selection in favor of individuals more capable of learning and working, and group selection in favor of groups in which individuals with more developed social behavior predominated.

Why do social factors play a leading role in the development of modern man?

Answer. Social factors of anthropogenesis include labor, social lifestyle, developed consciousness and speech. The role of social factors in anthropogenesis was revealed by Engels in his work “The Role of Labor in the Process of Transformation of Ape into Man” (1896). These factors played a leading role in the later stages of human development.

The most important factor in human evolution is labor. The ability to make tools is unique to humans. Animals can only use individual objects to obtain food (for example, a monkey uses a stick to get a treat).

Labor activity contributed to the consolidation of morphological and physiological changes in human ancestors.

An important change in human evolution was walking upright. Over many generations, as a result of natural selection, individuals with hereditary changes favoring upright walking were preserved. Adaptations for upright walking gradually developed: an S-shaped spine, an arched foot, a wide pelvis and chest, and massive bones of the lower extremities.

Walking upright resulted in the release of the arm. At first, the hand could only perform primitive movements. In the process of work, she improved and began to perform complex actions. Thus, the hand is not only an organ of labor, but also its product. The developed hand allowed man to make primitive tools. This gave him significant advantages in the struggle for existence.

Joint work activity contributed to the unity of team members and necessitated the exchange of sound signals. Communication contributed to the development of the second signaling system - communication using words. At first, our ancestors exchanged gestures and individual inarticulate sounds. As a result of mutations and natural selection, the oral apparatus and larynx were transformed, and speech was formed.

Work and speech influenced the development of the brain and thinking. Thus, over a long period of time, as a result of the interaction of biological and social factors, human evolution took place.

If the morphological and physiological characteristics of a person are inherited, then the ability to work, speech and thinking develop only in the process of upbringing and education. Therefore, with prolonged isolation of a child, his speech, thinking, and adaptability to life in society do not develop at all or develop very poorly.

Biological factors influence human evolution.

Historically, human development could not occur in isolation from the surrounding reality. This process was influenced by biological factors of human evolution, the same as they influenced the rest of living nature. However, research shows that biological factors alone are clearly not enough for anthropogenesis; social factors were also required.

The early stages of human evolution are characterized by the predominance of biological factors. Natural selection of individuals with better adaptability to constantly changing environmental conditions was of decisive importance.

There was also a selection of individuals who showed the ability to make primitive tools, without which obtaining food and protecting themselves from enemies became problematic.

At later stages, selection was already carried out on the basis of gregariousness and associated forms of communication. In the environment, only groups of individuals could continue to exist that could, through joint efforts, withstand surprises and unfavorable factors.

At certain stages, the biological factors of human evolution included individual selection, which was based on the selective death of individual individuals and contributed to the formation of human morphophysiological characteristics, such as upright posture, a large brain, and a developed hand.

Man was already different from the surrounding animal world in that he could speak, developed thinking and the ability to work. This is how modern man was formed in the process of anthropogenesis.

The biological factors of the historical-revolutionary process of human formation were exactly the same for all living nature. They became especially important in the early stages of human development. Charles Darwin wrote a lot about the role of biological factors for human evolution.

Biological factors in human evolution have created the preconditions for the occurrence of hereditary changes in him, which determine, for example, eye and hair color, height, and the body’s resistance to environmental influences.

Man's dependence on nature was especially felt in the early stages of his evolution. Only individuals who were characterized by endurance, physical strength, dexterity, intelligence and other useful qualities could survive and leave offspring to continue the family line.

The beginning of the improvement of tools significantly reduced the role of biological evolution. Technogenic evolution has forced man not to wait, as they say, for alms from nature. He no longer adapted painfully and slowly, but he consciously changed the surrounding nature itself and forced it to satisfy his needs. To do this, man used powerful tools.

Nevertheless, the biological factors of human evolution have not completely lost their influence on the animal world in general, and on humans in particular. Nature is still the reason for the ongoing evolution of man.