Somehow Tolstoy understood the role of the individual in history. “Tolstoy Great writer and philosopher Lev Nikolaevich Tolstoy

Taxon- a classification unit in the taxonomy of plant and animal organisms.

The main evidence of human origin from animals is the presence of rudiments and atavisms in his body.

Rudiments- these are organs that have been lost in the process historical development(evolution) their meaning and function and remaining in the form of underdeveloped formations in the body. They are laid down during the development of the embryo, but do not develop. Examples of rudiments in humans can be: coccygeal vertebrae (remains of the skeleton of the tail), appendix (process of the cecum), body hair; ear muscles (some people can move their ears); third eyelid.

Atavisms- this is the manifestation, in individual organisms, of characteristics that existed in individual ancestors, but were lost during evolution. In humans, this is the development of a tail and hair throughout the body.

Historical past of people

The first people on Earth. The name of the ape-man - Pithecanthropus - was given to one of the earliest finds, made in the 19th century in Java. For a long time this find was considered a transitional link from ape to man, the first representatives of the hominid family. These views were promoted morphological features: a combination of modern-looking bones of the lower limb with a primitive skull and intermediate brain mass. However, the Pithecanthropus of Java is quite late group hominids. Starting from the 20s of the twentieth century to the present time in the southern and East Africa an important discovery was made: the remains of bipedal Plio-Pleistocene primates (from 6 to 1 million years) were found. They marked the beginning of a new stage in the development of paleontology - the reconstruction of these stages of hominid evolution based on direct paleontological data, and not on the basis of various indirect comparative anatomical and embryological data.

The Age of the Bipedal Apes Australopithecus. The first australopithecus of East Africa - Zinjanthropus - was discovered by the spouses L. and M. Leakey. The brightest distinguishing feature Australopithecus - upright walking. This is evidenced by the structure of the pelvis. Upright walking is one of the oldest human acquisitions.

The first representatives of the human race in East Africa. Together with the massive australopithecines, other creatures lived in East Africa 2 million years ago. This first became known when next year After the discovery of Zinjanthropus, the remains of a miniature hominid were discovered, the brain volume of which was no less (and even more) than that of Australopithecus. It was later revealed that he was a contemporary of Zinjanthropus. Major discoveries made in the lowest layer, dating back to 2–1.7 million years. Its maximum thickness is 40 meters. The climate when this layer was laid was more humid and its inhabitants were zinjanthropus and prezinjanthropus. The latter did not last long. In addition, stones with traces of artificial processing were also found in this layer. Most often it was pebbles ranging in size from a walnut to 7–10 cm, with a few chips of the working edge. Initially it was assumed that the Zinjanthropes were able to do this, but after new discoveries it became obvious: either the tools were made by a more advanced Zinjanthropus, or both inhabitants were capable of such initial stone processing. Full Opposition Clamp Emergence thumb the hand should have been preceded by a period of predominance of a forceful grip, when the object was raked into a handful and clamped in the hand. Moreover, it was the nail phalanx of the thumb that experienced particularly strong pressure.

Prerequisites for anthropogenesis.Common ancestors great apes and humans were gregarious, narrow-nosed monkeys that lived in trees in tropical forests. The transition of this group to a terrestrial lifestyle, caused by climate cooling and the displacement of forests by steppes, led to upright walking. The straightened position of the body and the transfer of the center of gravity caused the replacement of the arched spinal column with an S-shaped one, which gave it flexibility. An arched springy foot was formed, the pelvis expanded, the chest became wider and shorter, the jaw apparatus was lighter, and most importantly, the forelimbs were freed from the need to support the body, their movements became more free and varied, and their functions became more complex. The transition from using objects to making tools is the boundary between ape and man. The evolution of the hand followed the path of natural selection of mutations useful for labor activity. Along with upright walking, the most important prerequisite for anthropogenesis was the herd lifestyle, which, with the development of work activity and the exchange of signals, led to the development of articulate speech. Specific ideas about surrounding objects and phenomena were generalized in abstract concepts, thinking and speech abilities developed. Higher nervous activity was formed, and articulate speech developed.

Stages of human development. There are three stages in human evolution: ancient people, ancient people and modern (new) people. Many populations of Homo sapiens did not replace each other sequentially, but lived simultaneously, fighting for existence and destroying the weaker.

Modern people. The emergence of modern people physical type occurred relatively recently (about 50 thousand years ago), who were called Cro-Magnons. Increased brain volume (1,600 cm3), well-developed articulate speech; construction of dwellings, the first beginnings of art ( rock painting), clothing, jewelry, bone and stone tools, the first domesticated animals - everything indicates that real man finally separated from his bestial ancestors. Neanderthals, Cro-Magnons and modern people form one species - Homo sapiens. Many years passed before people moved from an appropriating economy (hunting, gathering) to a producing economy. They learned to grow plants and tame some animals. In the evolution of Cro-Magnons great importance had social factors, the role of education and the transfer of experience has grown immeasurably.

Races of man

All modern humanity belongs to the same species - Homo sapiens. The unity of humanity follows from common origin, similarity of structure, unlimited crossing of representatives of different races and the fertility of offspring from mixed marriages. Inside the view - Homo sapiens- There are five major races: Negroid, Caucasoid, Mongoloid, Australoid, American. Each of them is divided into small races. Differences between races come down to features of skin color, hair, eyes, shape of the nose, lips, etc. These differences arose in the process of adaptation of human populations to local natural conditions. It is believed that the black skin absorbed ultraviolet rays. Narrow eyes protected from harsh sunlight in open spaces; a wide nose cooled the inhaled air faster by evaporation from the mucous membranes, on the contrary, a narrow nose warmed the cold inhaled air better, etc.

But thanks to work, man quickly escaped the influence of natural selection, and these differences quickly lost their adaptive significance.

Human races began to take shape, believed to have started to take shape, about 30–40 thousand years ago during the process of human settlement of the Earth, and then many racial characteristics had adaptive significance and were fixed by natural selection in the conditions of a certain geographical environment. All human races are characterized by the species-wide characteristics of Homo sapiens, and all races are absolutely equal in biological and mental respects and are on the same level evolutionary development.

There is no sharp boundary between the main races, and there are a number smooth transitions- small races, whose representatives have smoothed out or mixed features of the main masses. It is assumed that in the future, differences between races will completely disappear and humanity will be racially homogeneous, but with many morphological variants.

The races of a person should not be confused with concepts nation, people, language group . Various groups can be part of one nation, and the same races can be part of different nations.

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, phylum Chordata, subphylum Vertebrates, class Mammals, order Primates, family Hominids (Fig. 144).

Rice. 144. 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 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 type Chordata, characteristic common features organizations 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 opposite sides of 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 circulations and one left aortic arch; anucleate erythrocytes (in all other classes of vertebrates - nuclear); alveolar lungs. Besides these morphological features It should be noted that all mammals, including humans, are characterized by such progressive organizational features as high development of the central nervous system, especially the bark cerebral hemispheres; 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, i.e., 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 rest); 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 calf and long-term care for it; complex organization of relationships between individuals and high level 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 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 are characteristics that once existed in our ancestors and were subsequently lost, but the genes responsible for their development are still preserved even with certain conditions cause the formation of these ancient signs. Vivid examples atavisms are facial hair, outer tail, extra pairs of mammary glands, membranes between the fingers (Fig. 145).

Rice. 145. Human atavisms

Data from comparative embryology. In addition to the data of comparative anatomy, strong evidence of the origin of man from animals is the results comparative study ontogenesis of humans 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. Smooth surface cerebral hemispheres and continuous hair in the human fetus indicate a relationship with primitive mammals. Thus, the main features embryonic development a person is clearly defined by his animal origin.

Rice. 146. Apes

Similarities and differences between humans and apes. With great apes, people have a lot common features, for example such as large value body, absence of tail and cheek pouches, good development facial muscles and a similar structure of the skull (Fig. 146). Chimpanzees, gorillas, and orangutans have a well-developed brain, especially its frontal lobes, big number 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.

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 are capable of true upright walking (Fig. 147). 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.

Rice. 147. Monkey and human skeletons

A person has a very 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.

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 that are unique to humans.

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