Age periods of human development. The appearance of man on earth dates back to the period Principles and approaches
Human physical development is a complex of morphological and functional properties of the body, which determine the shape, size, weight of the body and its structural and mechanical qualities.
Introduction
Signs of physical development are variable. The physical development of a person is the result of the influence of hereditary factors (genotype) and environmental factors, and for a person - the entire complex of social conditions (phenotype). With age, the importance of heredity decreases, the leading role passes to individually acquired characteristics.
The physical development of children and adolescents is related to growth. Each age period - infancy, childhood, adolescence and youth - is characterized by specific growth characteristics of individual parts of the body. At each age period, the child’s body has a number of characteristic features unique to this age. Between the body of a child and an adult there are not only quantitative differences (body size, weight), but also, above all, qualitative ones.
Currently, there is an acceleration in human physical development. This phenomenon is called acceleration.
In my work, I will try to briefly characterize each of the main stages of individual human development.
The main stages of individual human development
When studying human development, its individual and age-related characteristics in anatomy and other disciplines, they are guided by scientifically based data on age periodization. The scheme of age periodization of human development, taking into account anatomical, physiological, and social factors, was adopted at the VII Conference on Problems of Age-Related Morphology, Physiology and Biochemistry (1965). It distinguishes twelve age periods (Table 1). Table 1
Individual development, or development in ontogenesis, occurs during all periods of life - from conception to death. In human ontogenesis, two periods are distinguished: before birth (intrauterine, prenatal - from the Greek natos - born) and after birth (extrauterine, postnatal).
Prenatal ontogeny
To understand the individual characteristics of the structure of the human body, it is necessary to become familiar with the development of the human body in the prenatal period. The fact is that each person has his own individual characteristics of external appearance and internal structure, the presence of which is determined by two factors. This is heredity, traits inherited from parents, as well as the result of the influence of the external environment in which a person grows, develops, learns, and works.
During the prenatal period, from conception to birth, for 280 days (9 calendar months), the embryo (embryo) is located in the mother’s body (from the moment of fertilization to birth). During the first 8 weeks, the main processes of formation of organs and body parts occur. This period is called embryonic (fetal), and the body of the future person is called an embryo (fetus). From 9 weeks of age, when the main external human features begin to appear, the organism is called a fetus, and the period is called fetal (fetal - from the Greek fetus - fruit).
The development of a new organism begins with the process of fertilization (fusion of sperm and egg), which usually occurs in the fallopian tube. The fused germ cells form a qualitatively new one-celled embryo - a zygote, which has all the properties of both sex cells. From this moment the development of a new (daughter) organism begins.
Optimal conditions for the interaction of sperm and egg are usually created within 12 hours after ovulation. The union of the sperm nucleus with the egg nucleus leads to the formation in a single-celled organism (zygote) of a diploid set of chromosomes characteristic of humans (46). The sex of the unborn child is determined by the combination of chromosomes in the zygote and depends on the sex chromosomes of the father. If an egg is fertilized by a sperm with sex chromosome X, then in the resulting diploid set of chromosomes two X chromosomes appear, characteristic of female body. When fertilized by a sperm with a Y sex chromosome, a combination of XY sex chromosomes is formed in the zygote, characteristic of the male body.
The first week of embryo development is the period of fragmentation (division) of the zygote into daughter cells (Fig. 1). Immediately after fertilization, during the first 3-4 days, the zygote divides and simultaneously moves along the fallopian tube towards the uterine cavity. As a result of the division of the zygote, a multicellular vesicle is formed - a blastula with a cavity inside (from the Greek blastula - sprout). The walls of this vesicle are formed by two types of cells: large and small. The walls of the vesicle, the trophoblast, are formed from the outer layer of small cells. Subsequently, trophoblast cells form the outer layer of the membranes of the embryo. Larger dark cells (blastomeres) form a cluster - the embryoblast (germinal nodule, embryonic rudiment), which is located medially from the trophoblast. From this accumulation of cells (embryoblast) the embryo and adjacent extra-embryonic structures (except the trophoblast) develop.
Fig.1. A - fertilization: 1 - sperm; 2 - egg; B; B - fragmentation of the zygote, G - morublastula: 1 - embryoblast; 2 - trophoblast; D - blastocyst: 1-embryoblast; 2 - trophoblast; 3 - amnion cavity; E - blastocyst: 1-embryoblast; 2-amnion cavity; 3 - blastocoel; 4 - embryonic endoderm; 5-amnionic epithelium - F - I: 1 - ectoderm; 2 - endoderm; 3 - mesoderm.
A small amount of fluid accumulates between the surface layer (trophoblast) and the germinal nodule. By the end of the 1st week of development (6th - 7th day of pregnancy), the embryo enters the uterus and is introduced (implanted) into its mucous membrane; implantation lasts about 40 hours. The surface cells of the embryo that form the vesicle, the trophoblast (from the Greek trophe - nutrition), secrete an enzyme that loosens the surface layer of the uterine mucosa, which is prepared for the implantation of the embryo into it. The forming villi (outgrowths) of the trophoblast come into direct contact with the blood vessels of the maternal body. Numerous trophoblast villi increase the surface of its contact with the tissues of the uterine mucosa. The trophoblast turns into the nutritious membrane of the embryo, which is called the villous membrane (chorion). At first, the chorion has villi on all sides, then these villi are retained only on the side facing the wall of the uterus. In this place, a new organ develops from the chorion and the adjacent mucous membrane of the uterus - the placenta (baby place). The placenta is an organ that connects the mother’s body with the embryo and provides its nutrition.
The second week of the embryo’s life is the stage when the embryoblast cells are divided into two layers (two plates), from which two vesicles are formed (Fig. 2). An ectoblastic (amniotic) vesicle is formed from the outer layer of cells adjacent to the trophoblast. An endoblastic (yolk) vesicle is formed from the inner layer of cells (embryo rudiment, embryoblast). The anlage ("body") of the embryo is located where the amniotic sac comes into contact with the yolk sac. During this period, the embryo is a two-layer shield, consisting of two layers: the outer germinal layer (ectoderm) and the inner germinal layer (endoderm).
Fig.2. The position of the embryo and germinal membranes at different stages of human development: A - 2-3 weeks; B - 4 weeks: 1 - amnion cavity; 2 - body of the embryo; 3 - yolk sac; 4 - tropholast; B - 6 weeks; G - fetus 4-5 months: 1 - body of the embryo (fetus); 2 - amnion; 3 - yolk sac; 4 - chorion; 5 - umbilical cord.
The ectoderm faces the amniotic sac, and the endoderm is adjacent to the yolk sac. At this stage, the surfaces of the embryo can be determined. The dorsal surface is adjacent to the amniotic sac, and the ventral surface is adjacent to the yolk sac. The trophoblast cavity around the amniotic and vitelline vesicles is loosely filled with strands of extraembryonic mesenchyme cells. By the end of the 2nd week, the length of the embryo is only 1.5 mm. During this period, the embryonic shield thickens in its posterior (caudal) part. Here, the axial organs (notochord, neural tube) subsequently begin to develop.
The third week of the embryo’s life is the period of formation of a three-layer shield (embryo). The cells of the outer, ectodermal plate of the germinal shield are displaced towards its posterior end. As a result, a cell ridge (primary streak) is formed, elongated in the direction of the longitudinal axis of the embryo. In the head (front) part of the primary streak, cells grow and multiply faster, resulting in the formation of a small elevation - the primary nodule (Hensen's node). The location of the primary node indicates the cranial (head end) of the embryonic body.
Rapidly multiplying, the cells of the primary streak and primary node grow laterally between the ectoderm and endoderm, thus forming the median germ layer - mesoderm. The mesoderm cells located between the sheets of the scutellum are called intraembryonic mesoderm, and those that migrate beyond its boundaries are called extraembryonic mesoderm.
Part of the mesoderm cells within the primary node grows especially actively forward from the head and tail ends of the embryo, penetrates between the outer and inner layers and forms a cellular cord - the dorsal string (notochord). At the end of the 3rd week of development, active cell growth occurs in the anterior part of the outer germ layer - the neural plate is formed. This plate soon bends, forming a longitudinal groove - the neural groove. The edges of the groove thicken, come closer and grow together, closing the neural groove into the neural tube. Subsequently, the entire neural tube develops nervous system. The ectoderm closes over the formed neural tube and loses connection with it.
During the same period, a finger-like outgrowth, the allantois, penetrates from the posterior part of the endodermal plate of the embryonic shield into the extra-embryonic mesenchyme (into the so-called amniotic leg), which does not perform certain functions in humans. Along the allantois, blood umbilical (placental) vessels grow from the embryo to the chorionic villi. A cord containing blood vessels that connects the embryo with the extraembryonic membranes (placenta) forms the abdominal stalk.
Thus, by the end of the 3rd week of development, the human embryo has the appearance of a three-layer plate, or a three-layer shield. In the region of the outer germ layer the neural tube is visible, and deeper - the dorsal chord, i.e. the axial organs of the human embryo appear. By the end of the third week of development, the length of the embryo is 2-3 mm.
The fourth week of life - the embryo, which looks like a three-layer shield, begins to bend in the transverse and longitudinal directions. The embryonic shield becomes convex, and its edges are delimited from the amnion surrounding the embryo by a deep groove - the trunk fold. The body of the embryo turns from a flat shield into a three-dimensional one; the ectoderm covers the body of the embryo on all sides.
From the ectoderm, the nervous system, the epidermis of the skin and its derivatives, the epithelial lining of the oral cavity, anal rectum, and vagina are subsequently formed. The mesoderm gives rise to internal organs (except for derivatives of the endoderm), the cardiovascular system, organs of the musculoskeletal system (bones, joints, muscles), and the skin itself.
The endoderm, once inside the body of the human embryo, curls up into a tube and forms the embryonic rudiment of the future intestine. The narrow opening connecting the embryonic intestine with the yolk sac later turns into the umbilical ring. The epithelium and all glands of the digestive system and respiratory tract are formed from the endoderm.
The embryonic (primary) gut is initially closed in front and behind. At the anterior and posterior ends of the body of the embryo, invaginations of the ectoderm appear - the oral fossa (future oral cavity) and the anal (anal) fossa. Between the cavity of the primary intestine and the oral fossa there is a two-layer (ectoderm and endoderm) anterior (oropharyngeal) plate (membrane). Between the intestine and the anal fossa there is a cloacal (anal) plate (membrane), also two-layered. The anterior (oropharyngeal) membrane breaks through in the 4th week of development. At the 3rd month, the posterior (anal) membrane breaks through.
As a result of bending, the body of the embryo is surrounded by the contents of the amnion - amniotic fluid, which acts as a protective environment that protects the embryo from damage, primarily mechanical (concussion).
The yolk sac lags in growth and in the 2nd month of intrauterine development it looks like a small sac, and then is completely reduced (disappears). The abdominal stalk lengthens, becomes relatively thin and later receives the name umbilical cord.
During the 4th week of embryo development, differentiation of its mesoderm, which began in the 3rd week, continues. The dorsal part of the mesoderm, located on the sides of the notochord, forms paired thickened projections - somites. Somites are segmented, i.e. are divided into metameric regions. Therefore, the dorsal part of the mesoderm is called segmented. Segmentation of somites occurs gradually in the direction from front to back. On the 20th day of development, the 3rd pair of somites is formed, by the 30th day there are already 30 of them, and on the 35th day - 43-44 pairs. The ventral part of the mesoderm is not divided into segments. It forms two plates on each side (the unsegmented part of the mesoderm). The medial (visceral) plate is adjacent to the endoderm (primary gut) and is called the splanchnopleura. The lateral (outer) plate is adjacent to the wall of the body of the embryo, to the ectoderm, and is called the somatopleura.
From the splanchno- and somatopleura the epithelial cover of the serous membranes (mesothelium), as well as the lamina propria of the serous membranes and the subserosal base develop. The mesenchyme of the splanchnopleura also goes to the construction of all layers of the digestive tube, except for the epithelium and glands, which are formed from the endoderm. The space between the plates of the unsegmented part of the mesoderm turns into the body cavity of the embryo, which is divided into the peritoneal, pleural and pericardial cavities.
Fig.3. Cross section through the body of the embryo (diagram): 1 - neural tube; 2 - chord; 3 - aorta; 4 - sclerotome; 5 - myotome; 6 - dermatome; 7 - primary gut; 8 - body cavity (whole); 9 - somatopleura; 10 - splanchnopleura.
The mesoderm at the border between the somites and the splanchnopleura forms nephrotomes (segmental legs), from which the tubules of the primary kidney and gonads develop. Three primordia are formed from the dorsal part of the mesoderm - somites. The anteromedial portion of the somites (sclerotome) is used to build skeletal tissue, which gives rise to the cartilage and bones of the axial skeleton - the spine. Lateral to it lies the myotome, from which skeletal muscles develop. In the posterolateral part of the somite there is an area - the dermatome, from the tissue of which the connective tissue base of the skin - the dermis - is formed.
In the head section, on each side of the embryo, from the ectoderm in the 4th week, the rudiments of the inner ear (first the auditory pits, then the auditory vesicles) and the future lens of the eye are formed. At the same time, the visceral parts of the head are reconstructed, which form the frontal and maxillary processes around the oral bay. Posteriorly (caudally) of these processes, the contours of the mandibular and sublingual (hyoid) visceral arches are visible.
On the anterior surface of the embryo’s body, elevations are visible: the cardiac and behind them the hepatic tubercles. The depression between these tubercles indicates the place of formation of the transverse septum - one of the rudiments of the diaphragm. Caudal to the hepatic tubercle is the abdominal stalk, which contains large blood vessels and connects the embryo to the placenta (umbilical cord). The length of the embryo by the end of the 4th week is 4-5 mm.
Fifth to eighth weeks
During the period from the 5th to the 8th week of the embryo’s life, the formation of organs (organogenesis) and tissues (histogenesis) continues. This is the time of early development of the heart and lungs, the complication of the structure of the intestinal tube, the formation of visceral arches, and the formation of capsules of the sensory organs. The neural tube closes completely and expands in the cerebrum (the future brain). At the age of about 31-32 days (5th week), the length of the embryo is 7.5 mm. At the level of the lower cervical and 1st thoracic segments of the body, fin-like rudiments (buds) of the arms appear. By the 40th day, the rudiments of the legs are formed.
At the 6th week (the parietal-coccygeal length of the embryo is 12 - 13 mm), the outer ear buds are noticeable, from the end of the 6-7th week - the buds of the fingers and then the toes.
By the end of the 7th week (embryo length is 19-20 mm), eyelids begin to form. Thanks to this, the eyes are outlined more clearly. At the 8th week (embryo length 28-30 mm), the formation of embryonic organs ends. From the 9th week, i.e. from the beginning of the 3rd month, the embryo (parietal-coccygeal length 39-41 mm) takes on the appearance of a person and is called a fetus.
Third to ninth months
Starting from three months and throughout the entire fetal period, further growth and development of the resulting organs and body parts occurs. At the same time, differentiation of the external genitalia begins. The nails on the fingers are laid. From the end of the 5th month (length 24.3 cm), eyebrows and eyelashes become noticeable. At the 7th month (length 37.1 cm), the eyelids open and fat begins to accumulate in the subcutaneous tissue. In the 10th month (length 51 cm) the fetus is born.
Critical periods of ontogenesis
In the process of individual development, there are critical periods when the sensitivity of the developing organism to the effects of damaging factors of the external and internal environment is increased. There are several critical periods of development. These most dangerous periods are:
1) time of development of germ cells - oogenesis and spermatogenesis;
2) the moment of fusion of germ cells - fertilization;
3) implantation of the embryo (4-8 days of embryogenesis);
4) the formation of the rudiments of the axial organs (brain and spinal cord, spinal column, primary intestine) and the formation of the placenta (3-8th week of development);
5) stage of increased brain growth (15-20th week);
6) formation of functional systems of the body and differentiation of the genitourinary apparatus (20-24th week of the prenatal period);
7) the moment of birth of a child and the neonatal period - the transition to extrauterine life; metabolic and functional adaptation;
8) the period of early and first childhood (2 years - 7 years), when the formation of relationships between organs, systems and organ apparatuses ends;
9) adolescence (puberty - for boys from 13 to 16 years, for girls - from 12 to 15 years).
Simultaneously with the rapid growth of the organs of the reproductive system, emotional activity intensifies.
Postnatal ontogeny. Newborn period
Immediately after birth, there begins a period called the newborn period. The basis for this allocation is the fact that at this time the baby is fed with colostrum for 8-10 days. Newborns in the initial period of adaptation to the conditions of extrauterine life are divided according to the level of maturity into full-term and premature. Intrauterine development for full-term babies it lasts 39-40 weeks, for premature babies - 28-38 weeks. When determining maturity, not only these terms are taken into account, but also body mass (weight) at birth.
Newborns with a body weight of at least 2500 g (with a body length of at least 45 cm) are considered full-term, and newborns weighing less than 2500 g are considered premature. In addition to weight and length, other dimensions are also taken into account, for example, chest circumference in relation to body length and head circumference in relation to chest circumference. It is believed that the chest girth at nipple level should be 9-10 cm greater than 0.5 body length, and the head girth should be no more than 1-2 cm greater than the chest girth.
Breast period
The next period - the infancy - lasts up to a year. The beginning of this period is associated with the transition to feeding on “mature” milk. During the breast period, the greatest intensity of growth is observed, compared to all other periods of extrauterine life. Body length increases from birth to one year by 1.5 times, and body weight triples. From 6 months baby teeth begin to emerge. In infancy, unevenness in body growth is pronounced. In the first half of the year, infants grow faster than in the second. In each month of the first year of life, new development indicators appear. In the first month, the child begins to smile in response to adults addressing him, at 4 months. persistently tries to stand on her feet (with support), at 6 months. tries to crawl on all fours, at 8 he tries to walk, by the age of one year the child usually walks.
Early childhood period
The period of early childhood lasts from 1 year to 4 years. At the end of the second year of life, teething ends. After 2 years, the absolute and relative values of annual increases in body size quickly decrease.
First childhood period
At the age of 4, the period of first childhood begins, which ends at the age of 7. Starting at the age of 6, the first permanent teeth appear: the first molar (large molar) and the medial incisor on the lower jaw.
The age from 1 to 7 years is also called the period of neutral childhood, since boys and girls are almost the same in size and body shape.
Second childhood period
The period of second childhood lasts for boys from 8 to 12 years, for girls - from 8 to 11 years. During this period, gender differences in body size and shape are revealed, and increased body length growth begins. Girls' growth rates are higher than those of boys, since puberty begins on average two years earlier in girls. Increased secretion of sex hormones (especially in girls) causes the development of secondary sexual characteristics. The sequence of appearance of secondary sexual characteristics is fairly constant. In girls, mammary glands first form, then pubic hair appears, then in the armpits. The uterus and vagina develop simultaneously with the formation of the mammary glands. The process of puberty is expressed to a much lesser extent in boys. Only towards the end of this period do they begin to experience accelerated growth of the testicles, scrotum, and then the penis.
Teenage years
The next period - adolescence - is also called puberty, or puberty. It lasts for boys from 13 to 16 years, for girls - from 12 to 15 years. At this time, there is a further increase in growth rates - a pubertal leap, which affects all body sizes. The greatest increases in body length in girls occur between 11 and 12 years, and in body weight - between 12 and 13 years. In boys, an increase in length is observed between 13 and 14 years, and an increase in body weight between 14 and 15 years. The growth rate of body length in boys is especially high, as a result of which at 13.5-14 years old they overtake girls in body length. Due to increased activity of the hypothalamic-pituitary system, secondary sexual characteristics are formed. In girls, the development of the mammary glands continues, and hair growth is observed on the pubis and in the armpits. The clearest indicator of puberty in the female body is the first menstruation.
During adolescence, boys undergo intense puberty. By the age of 13, their voice changes (mutates) and pubic hair appears, and at the age of 14, hair appears in the armpits. At the age of 14-15, boys experience their first emissions (involuntary eruptions of sperm).
Boys, compared to girls, have a longer pubertal period and a more pronounced pubertal growth spurt.
Adolescence
Adolescence lasts for boys from 18 to 21 years, and for girls from 17 to 20 years. During this period, the process of growth and formation of the organism basically ends and all the main dimensional characteristics of the body reach their definitive (final) size.
In adolescence, the formation of the reproductive system and the maturation of the reproductive function are completed. The ovulatory cycles in a woman, the rhythm of testosterone secretion and the production of mature sperm in a man are finally established.
Mature, elderly, senile age
In adulthood, the shape and structure of the body changes little. Between 30 and 50 years, body length remains constant and then begins to decrease. In old age and senility, gradual involutive changes in the body occur.
Individual differences in growth and development
Individual differences in the process of growth and development can vary widely. The existence of individual fluctuations in the processes of growth and development served as the basis for the introduction of such a concept as biological age, or developmental age (as opposed to passport age).
The main criteria for biological age are:
1) skeletal maturity - (the order and timing of skeletal ossification);
2) dental maturity - (timing of eruption of milk and permanent teeth);
3) the degree of development of secondary sexual characteristics. For each of these criteria of biological age - “external” (skin), “dental” and “bone” - rating scales and normative tables have been developed that make it possible to determine the chronological (passport) age based on morphological features.
Factors influencing individual development
Factors influencing individual development (ontogenesis) are divided into hereditary and environmental (influence of the external environment).
The degree of hereditary (genetic) influence varies different stages growth and development. The impact of hereditary factors on total body size increases from the newborn period (tm) to the second childhood, with subsequent weakening by 12-15 years.
The influence of environmental factors on the processes of morphofunctional maturation of the body can be clearly seen in the example of the timing of menarche (menstruation). Studies of growth processes in children and adolescents in various geographical zones have shown that climatic factors have almost no effect on growth and development if living conditions are not extreme. Adaptation to extreme conditions causes such a profound restructuring of the functioning of the entire organism that it cannot but affect growth processes.
Sizes and proportions, body weight
Among the body sizes, total (from the French total - whole) and partial (from the Latin pars - part) are distinguished. Total (general) body dimensions are the main indicators of human physical development. These include body length and weight, as well as chest girth. Partial (partial) body sizes are components of the total size and characterize the size of individual parts of the body.
Body sizes are determined through anthropometric surveys of various populations.
Most anthropometric indicators have significant individual variations. Table 2 shows some average anthropometric indicators in postnatal ontogenesis.
Body proportions depend on the age and gender of the person (Fig. 4). Body length and its age-related changes, as a rule, vary from person to person. For example, differences in the body length of newborns during a normal pregnancy range from 49-54 cm. The greatest increase in the body length of children is observed in the first year of life and averages 23.5 cm. In the period from 1 to 10 years, this indicator gradually decreases by an average of 10.5 - 5 cm per year. From the age of 9, sex differences in growth rate begin to appear. Body weight gradually increases in most people from the first days of life until about 25 years of age, and then remains unchanged.
Fig. 4 Changes in the proportions of body parts during human growth.
KM - middle line. The numbers on the right show the ratio of body parts in children and adults, the numbers below show age.
table 2
Length, weight and body surface area in post-natal orthogynesis
Table 2
After 60 years, body weight, as a rule, begins to gradually decrease, mainly as a result of atrophic changes in tissues and a decrease in their water content. Total body weight is made up of a number of components: skeletal mass, muscle mass, fatty tissue, internal organs and skin. For men, the average body weight is 52-75 kg, for women - 47-70 kg.
In old and senile age, characteristic changes can be observed not only in body size and weight, but also in its structure; These changes are studied by the special science of gerontology (gerontos - old man). It should be especially emphasized that an active lifestyle, regular classes Physical culture slows down the aging process.
Acceleration
It should be noted that over the past 100-150 years there has been a noticeable acceleration in the somatic development and physiological maturation of children and adolescents - acceleration (from the Latin acceleratio - acceleration). Another term for the same trend is "epochal shift." Acceleration is characterized by a complex set of interrelated morphological, physiological and mental phenomena. To date, morphological indicators of acceleration have been determined.
Thus, the body length of children at birth over the past 100-150 years has increased by an average of 0.5-1 cm, and their weight has increased by 100-300 g. During this time, the weight of the mother’s placenta has also increased. An earlier equalization of the ratios of chest and head circumferences is also noted (between the 2nd and 3rd month of life). Modern one-year-old children are 5 cm longer and 1.5-2 kg heavier than their peers in the 19th century.
Over the past 100 years, the body length of preschool children has increased by 10-12 cm, and for schoolchildren - by 10-15 cm.
In addition to an increase in body length and weight, acceleration is characterized by an increase in the size of individual parts of the body (segments of limbs, thickness of skin-fat folds, etc.). Thus, the increase in chest girth in relation to the increase in body length was small. The onset of puberty in modern adolescents occurs approximately two years earlier. The acceleration of development also affected motor functions. Modern teenagers run faster, jump farther from a standing position, and do more pull-ups on the horizontal bar.
The epochal shift (acceleration) affects all stages of human life, from birth to death. For example, the body length of adults also increases, but to a lesser extent than in children and adolescents. Thus, at the age of 20-25 years, the body length of men increased by an average of 8 cm.
Acceleration covers the entire body, affecting body size, the growth of organs and bones, and the maturation of the gonads and skeleton. In men, changes in the acceleration process are more pronounced than in women.
Men and women are distinguished by sexual characteristics. These are primary signs (genital organs) and secondary ones (for example, development of pubic hair, development of mammary glands, change in voice, etc.), as well as body features, proportions of body parts.
The proportions of the human body are calculated as a percentage based on measurements of longitudinal and transverse dimensions between boundary points established on various protrusions of the skeleton.
The harmony of body proportions is one of the criteria when assessing a person’s health status. If there is a disproportion in the structure of the body, one can think about a violation of growth processes and the causes that determined it (endocrine, chromosomal, etc.). Based on the calculation of body proportions in anatomy, three main types of human physique are distinguished: mesomorphic, brachymorphic, dolichomorphic. The mesomorphic body type (normosthenics) includes people whose anatomical features are close to the average normal parameters (taking into account age, gender, etc.). People with a brachymorphic body type (hypersthenics) have predominantly transverse dimensions, well-developed muscles, and are not very tall. The heart is positioned transversely due to the high-standing diaphragm. In hypersthenics, the lungs are shorter and wider, the loops of the small intestine are located predominantly horizontally. Persons with a dolichomorphic body type (asthenics) are distinguished by a predominance of longitudinal dimensions, have relatively longer limbs, poorly developed muscles and a thin layer of subcutaneous fat, and narrow bones. Their diaphragm is located lower, so the lungs are longer, and the heart is located almost vertically. Table 3 shows the relative sizes of body parts in humans different types physique.
Table 3.
Conclusion
What conclusion can be drawn from the above?
Human growth is uneven. Each part of the body, each organ develops according to its own program. If we compare the growth and development of each of them with a long-distance runner, it is not difficult to discover that during this multi-year “run” the leader of the competition is constantly changing. In the first month of embryonic development, the head is in the lead. In a two-month fetus, the head is larger than the body. This is understandable: the brain is located in the head, and it is the most important organ that coordinates and organizes difficult work organs and systems. The development of the heart, blood vessels and liver also begins early.
In a newborn baby, the head reaches half its final size. Until 5-7 years of age, there is a rapid increase in body weight and length. In this case, the arms, legs and torso grow alternately: first - the arms, then the legs, then the torso. The size of the head increases slowly during this period.
In junior school age from 7 to 10 years, growth is slower. If earlier the arms and legs grew more quickly, now the torso becomes the leader. It grows evenly, so that the proportions of the body are not disturbed.
During adolescence, hands grow so rapidly that the body does not have time to adapt to their new sizes, hence some clumsiness and sweeping movements. After this, the legs begin to grow. Only when they reach their final size is the body included in growth. First it grows in height, and only then begins to grow in width. During this period, the human physique is finally formed.
If you compare the body parts of a newborn and an adult, it turns out that the size of the head has only doubled, the torso and arms have become three times larger, and the length of the legs has increased five times.
An important indicator of the development of the body is the appearance of menstruation in girls and wet dreams in boys; it indicates the onset of biological maturity.
Along with the growth of the body comes its development. Human growth and development different people occur at different times, so anatomists, doctors, and physiologists distinguish between calendar age and biological age. Calendar age is calculated from the date of birth, biological age reflects the degree of physical development of the subject. The latter is different for each person. It may happen that people who are at the same biological age may differ by 2-3 years calendar year, and this is completely normal. Girls tend to develop faster.
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11. Encyclopedia "Wikipedia"
A person goes through different age periods from birth to death.
There are several popular scientific approaches who consider this issue from a social and pedagogical point of view.
Concept
Age periodization is a classification of the level of human development depending on his age, from birth to death.
This indicator has not only social, psychological, but also legal significance.
Thus, at a certain age, criminal liability begins, the right to represent one’s interests, the right to vote, the right to receive a pension, etc. appear.
Any stage of a person’s life has its own characteristics, problems and priorities. Each segment of life corresponds to a certain level of socialization, a specific mental state.
Periodization of mental development
Mental development- this is a person’s state by which one can judge the level of maturity of his personality from a psychological point of view. Psychological age consists of the following components:
![](https://i0.wp.com/psyholic.ru/wp-content/uploads/2018/09/ne_prodolzhitelnostju_zhizni_tak_lekarstvami_ot_st.jpg)
In reality, individual components of a person’s psychological age may not coincide at all with each other and with real biological age.
Classification by year
General classification by year in the table:
Age period |
Features of development and communication |
|
newborns |
The birth is serious, since its intrauterine existence abruptly ends and it finds itself in a new, unfamiliar environment. In early infancy, the child is inextricably linked with the mother, through contact with her he learns the world. Development occurs unconsciously, reflexively, in accordance with the genetic program laid down by nature. |
|
Significant development of the psyche, the emergence of the first social skills - smiling, laughter, contact with adults, recognition of loved ones. The mother still has primary importance for the child, but he is already beginning to realize the possibility of his existence separately from her. |
||
There is a psychological separation of the child from the mother, awareness of his own “I”. At the age of 3, most children experience a developmental crisis - the desire to demonstrate their autonomy and independence, negativism, denial. Children often do not want to comply with the requests of adults and strive to act in accordance with their desires. Refusal to satisfy a request causes... Children begin to talk and learn to play with other children. Vocabulary at this age is still limited. |
||
Children learn the rules and norms that exist in society. Recognize what behavior is acceptable. They begin to actively interact with peers. Parents at this age gradually fade into the background. Vocabulary and knowledge about the world around us is constantly expanding. Children under 7 years old constantly ask many questions that they want answers to. The child gradually loses his childish spontaneity. His internal mental life is formed, actively developing, and his own judgments appear. |
||
During this period, school life takes on special significance. The child develops logical thinking, self-discipline, ability to control emotions. Morality develops, basic moral principles are established and an attitude towards the laws existing in society is developed. |
||
The most difficult period in the life of every person, when significant hormonal changes occurring in the body affect behavior, self-esteem, relationships with peers and family. The main problem is that as a result of significant changes in the child’s appearance (the development of secondary sexual characteristics), he begins to recognize himself as an adult, but due to his age, for society, the teenager still remains a child. The need to obey parents and teachers often causes discontent and protest. Relationships with peers come first, who become the main authorities. Communication skills (the ability to join a team, win friends, be liked by the opposite sex) acquire special importance. |
||
Young people |
At this age, all teenage storms are left behind. Young people gain a certain awareness of their interests and preferences. The picture of perception of the surrounding world is finally formed, a system of moral principles is established. During this period, the choice of further direction of development in social terms occurs -. As a rule, at the same time, the period of the first serious relationship, the first adult begins. |
|
Adults |
The period of maturity and maximum performance. At this time, people are at the peak of their intellectual, physical, and mental development. This is a period of active professional activity, creating a family,. |
|
At this time, most people already have a stable profession, family, and children are growing up. At the same time, the first signs of aging appear - wrinkles, gray hair, decreased sexual and physical activity. A midlife crisis strikes people regardless of their degree of social and mental well-being. At this time, there is an assessment of the stages of life passed, an analysis of one’s successes and failures. Often a decision is made about the need for changes in life, to correct mistakes made earlier. Middle age is a time when most people's children are in their teens and their parents are old or deceased. Difficulties communicating with children and the need to care for elderly parents require significant energy expenditure. |
||
46 - 60 years |
As a rule, having overcome the difficult period of middle age, people closer to 60 years old enter a time of stability and calm self-confidence. Most of life is left behind and at this time people begin to truly appreciate what they have. |
|
61-75 years old (elderly) |
For most older people, health problems come first, since by this time all chronic diseases worsen and general weakness of the body appears. At the same time, social activity, the desire for communication, and involvement in family life do not weaken. Many older people continue to work, which gives them an additional incentive to live. |
|
76-90 years (old) |
Most old people are already retired and their sphere of interests is limited to their own health, communication with their family, and caring for their grandchildren. Old people's character changes significantly - it becomes less emotional and rigid. Often at this age a certain immaturity and selfishness manifests itself. Many people experience anxiety, insomnia, and fear of death. |
|
over 90 years old (centenarians) |
Physical lack of independence, passivity, anxiety and uncertainty are actively manifested. It is of great importance to have close people nearby who can provide maximum assistance. For the majority, the fear of death becomes dull and is replaced by an objective awareness of the imminent end of life’s journey. |
Principles and approaches
The classification is based on the assessment of the following indicators:
![](https://i2.wp.com/psyholic.ru/wp-content/uploads/2018/09/otrazhenie-molodosti-i-starosti-foto-tom-hassi.png)
The basis of periodization is determining a person's real age, which is characterized by the above features.
At the same time, additional analysis of the mental and biological state allows for a more individual approach to personality assessment.
Elkonina
D.B. Elkonin was inclined to believe that age gradation has great scientific significance. The construction of a competent classification allows us to determine the driving forces of human development at each stage of his life.
The knowledge obtained as a result contributes to the formation of the most complete pedagogical system, the development of effective rules for educating the younger generation.
The scientist attached particular importance to the early stages of a person’s life, when the basic system of values is laid and a worldview is formed. Standard age phases Elkonin divided into periods:
![](https://i2.wp.com/psyholic.ru/wp-content/uploads/2018/09/otrazhenie-molodosti-i-starosti-foto-tom-hassi-300x209.png)
Each period is assessed according to four indicators:
- social impact— the influence of society on the formation of a child’s personality;
- leading activities- type of activity that has a priority impact on the mental state;
- a crisis— a negative period within each phase that must be overcome in order to move to the next level.
- neoplasms— knowledge, skills and abilities that have emerged at a new stage.
Erickson
E. Erikson identified 8 stages of personality development, each of which corresponds to specific task.
According to the scientist, at each stage when achieving a task, a person exhibits priority strengths and weaknesses.
![](https://i2.wp.com/psyholic.ru/wp-content/uploads/2018/09/49i8fu9s.jpg)
Vygotsky
L.S. Vygotsky paid special attention to childhood because he believed that understanding the specifics of each stage of a child’s development gives parents the opportunity to adjust their behavior and better understand the child.
Periods identified by Vygotsky:
![](https://i1.wp.com/psyholic.ru/wp-content/uploads/2018/09/ne_prodolzhitelnostju_zhizni_tak_lekarstvami_ot_st-300x203.jpg)
Vygotsky and his periodization of mental development:
Freud
Z. Freud believed that human behavior is the result of the work of his unconscious. The main driving force is sexual energy.
The scientist identified the following stages of development of sexuality:
![](https://i2.wp.com/psyholic.ru/wp-content/uploads/2018/09/9b2a3a0bca00a4156e54c32a78f73c86.jpg)
Problems of periodization
The actual age of a person does not always coincide with the level of his mental development, with the degree of socialization.
Most of the outlined boundaries can be shifted in any direction, taking into account the characteristics of a particular individual. The most vague boundaries periodization in relation to adolescence.
In any case, one period gives way to another, when qualities and properties appear that were not there before.
Transition to the next stage of development and attitude automatically means a change in life period.
Thus, at every stage of life, a person is characterized by certain features emotional, mental, intellectual development.
The issue of age periodization has worried many famous scientists and continues to arouse interest in modern science.
Taxon is 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 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 are a 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 facilitated by morphological features: a combination of modern-looking bones of the lower limb with a primitive skull and intermediate brain mass. However, Pithecanthropus of Java is a rather late group of hominids. From the 20s of the twentieth century to the present, an important discovery was made in southern and eastern Africa: the remains of bipedal Plio-Pleistocene primates (from 6 to 1 million years ago) were found.
years). 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 era 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, the 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. The most important discoveries were 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. The emergence of the fully opposable thumb grip must have been preceded by a period of predominant power grip, when the object was grabbed by the handful and clamped in the hand.
Moreover, it was the nail phalanx of the thumb that experienced particularly strong pressure.
Prerequisites for anthropogenesis. The common ancestors of 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 work 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.
Concrete ideas about surrounding objects and phenomena were generalized into abstract concepts, and mental 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.
Human Ancestors | Progressive features in appearance | Lifestyle | Tools |
Parapithecus (discovered in Egypt in 1911) | We walked on two legs. Low forehead, brow ridges, hairline |
Considered to be the oldest ape | Tools in the form of a baton; hewn stones |
Dryopithecus (bone remains found in Western Europe, South Asia and East Africa. Antiquity from 12 to 40 million years) | According to most scientists, Dryopithecus is considered a common ancestral group for modern apes and humans. | ||
Australopithecus (bone remains dating back 2.6-3.5 million years were found in Southern and Eastern Africa) | They had a small body (long. 120–130 cm), weight 30–40 kg, brain volume 500–600 cm2, moved on two legs. |
They consumed plant and meat foods and lived in open areas (such as savannas). Australopithecines are also considered as a stage of human evolution that immediately preceded the emergence of the most ancient people (archanthropes). | Sticks, stones, and animal bones were used as tools. |
Pithecanthropus (the oldest man, remains discovered - Africa, Mediterranean, Java; 1 million years ago) | Height 150 cm; brain volume 900–1,000 cm2, low forehead, with brow ridge; jaws without chin protrusion | Social lifestyle; They lived in caves and used fire. | Primitive stone tools, sticks |
Sinanthropus (China and others, 400 thousand years ago) | Height 150–160 cm; brain volume 850–1,220 cm3, low forehead, with brow ridge, no mental protuberance | They lived in herds, built primitive dwellings, used fire, dressed in skins | Tools made of stone and bones |
Neanderthal (ancient man); Europe, Africa, Asia; about 150 thousand years ago | Height 155–165 cm; brain volume 1,400 cm3; few convolutions; forehead low, with brow ridge; the chin protuberance is poorly developed | The social way of life, the construction of hearths and dwellings, the use of fire for cooking, dressed in skins. They used gestures and primitive speech to communicate. A division of labor appeared. First burials. |
Tools made of wood and stone (knife, scraper, multifaceted points, etc.) |
Cro-Magnon - first modern man (everywhere; 50–60 thousand years ago) | Height up to 180 cm; brain volume - 1,600 cm2; high forehead; the convolutions are developed; lower jaw with mental protuberance | Tribal community. They belonged to the species Homo sapiens. Construction of settlements. The emergence of rituals. The emergence of art, pottery, agriculture. Developed. Developed speech. Domestication of animals, cultivation of plants. They had rock paintings. |
Various tools made of bone, stone, wood |
Modern people.
The emergence of people of the modern 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; the construction of dwellings, the first rudiments 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 humans 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 increased immeasurably.
Races of man
All modern humanity belongs to one 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. Within the species - Homo sapiens - there are five large 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.
The races of man began to take shape began to take shape, it is believed, around 30–40 thousand years ago.
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 a certain geographical environment.
All human races are characterized by species-wide characteristics of Homo sapiens, and all races are absolutely equal in biological and mental respects and are at the same level of evolutionary development.
There is no sharp boundary between the main races, and there are a number of smooth transitions - small races, whose representatives have smoothed out or mixed the 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.
Human races should not be confused with the concepts of nation, people, or linguistic group.
Different groups can be part of one nation, and the same races can be part of different nations.
The emergence of ancient people
Human Origins
The emergence of ancient people
Activities of ancient people. Hunting, gathering
Glossary
Personalities
Additional Information
Literature and sources used
What does the history of Kazakhstan study in 6th grade?
Dear friend, today we will begin to study the history of mankind, its first stage - the history of ancient Kazakhstan.
In time immemorial, primitive people lived on the territory of ancient Kazakhstan; after several thousand years they were replaced by various tribes and tribal unions: the Sakas, Uysunis, Huns, Sarmatians and other tribes.
We will travel in the footsteps of people's material culture, visit ancient caves and dwellings.
Let's consider the tools, main occupations, art and religion of ancient people.
Let us fast forward on our journey through the centuries, when people learned to make weapons and tools not only from stone and wood, but also mastered copper, bronze, and later iron.
Our ancestors made a very long journey in their development from anthropoid apes to highly organized tribes with rich history and original culture.
We learn about the lives of people in the past from the traces they left, which are called historical sources.
Historical sources are of three types: material, written, ethnographic.
In the 6th grade we will get acquainted with the history of ancient Kazakhstan from material sources - the remains of ancient people, tools, dwellings, which were obtained during archaeological excavations.
Written sources – ancient signs left behind, writings on stone and paper.
Ethnographic - the spiritual heritage of the people: myths, legends, proverbs, sayings passed down by word of mouth to many generations.
We are connected with our distant ancestors by an invisible but continuous thread of time that permeates the destinies of hundreds of generations.
Let us remember that the countdown of years BC. is carried out in reverse descending order, counting years new era-increasingly. The thread of time is stretched from the past, through the present, into the future. As in the life of every person, in the history of peoples and states there are periods of growth: birth, youth, flourishing, withering-old age and death.
But in the fading period, new forces mature, which in turn, having gone through all stages of development ( evolution), will make room for their successors. And so forever, as long as humanity exists.
Peoples and states in each subsequent development cycle are very different from their predecessors in characteristics and public life, according to the level of knowledge. Therefore, society does not stand still, it is constantly developing.
The history of ancient Kazakhstan in 6th grade can be divided into three eras:
- The first era is the era of stone
- Second era - Bronze Age
- The third era - the age of iron
People in each historical era went through their own stages of development (evolution) in three directions: the evolution of the formation and development of man, his physical appearance; the evolution of the development of tools used by man; evolution of human social relations .
Human Origins
Humanity has always been concerned about the mystery of its origin.
The most ancient people found a simple answer: they traced their ancestry to some animal in the world around them (bear, snake, eagle, fish, etc.). But, starting with early civilizations, the religious point of view took over, according to which the first people either appeared from the parts of some deity, or were created by the creativity of some divine force. Not without the influence of pottery, earth or clay was considered the most suitable material for the creation of man.
From the point of view of scientists, the answer given by religion to the question of the origin of man is not convincing.
However, science was able to offer its own version of the answer only in the 19th century. Thanks to the courage of mind and genius Charles Darwin, who formulated the law according to which, under the influence of the environment, small changes can occur in animals, sometimes completely imperceptible, which, helping to survive and being passed on to descendants, after hundreds and thousands of generations can lead to very strong transformations.
Therefore, man was not created as he is, but went through, step by step, a long path of evolution.
The emergence of ancient people
The era of the ancient Stone Age is the time of the formation of humanity. Man was formed, like all living beings, as a result of long evolutionary development. Using the remains found, archaeologists have determined the stages of human development. There are three stages in human development:
1. The most ancient people, which include the “southern monkey”, “homo habilis”, Pithecanthropus, Sinanthropus.
Ancient people are Neanderthals.
3. Modern humans, including fossil Cro-Magnons and modern humans (Homo sapiens).
Humanity is always interested in the question: when and where did man arise?
About 3 million years ago, in the vast expanses of African shrouds, human fossil creatures lived in Taung.
This fossil man was called the “southern ape”, which became the link between the ape and the earliest man.
Skeletal remains australopithecus found in South and East Africa, in Australia. Australopithecus lived about 2.6 million years ago.
Australopithecus looked like a monkey: the body was covered with thick hair, the lower limbs were longer than the front ones, and he walked on two legs. He collected fruits and roots with his hands, held objects, and performed simple movements.
The first tools of labor of ancient man were digging stick, pointed stone, club. With their help, he obtained food for himself.
Man made the first tools mainly from stone. They were very rude and primitive. Since tools were made mainly of stone, scientists call this period the “Stone Age.”
Scientists call the first man “a clever man.” His earliest remains were found in Africa, in Kenya. He lived 1 million 750 thousand years ago.
One of the oldest people was Pithecanthropus The skeleton of Pithecanthropus was first found on the island of Java (Southeast Asia) in 1891.
He lived approximately 1 million years ago.
The first discoveries of Pithecanthropus date back to end of the 19th century century, when in 1891-1892.
Dutch doctor Eugene Dubois, during excavations on the island of Java, discovered ancient human remains (a skull cap and long bones of the lower extremities).
The skull is characterized by a primitive structure and preservation of a number of ape-like characteristics: prominent brow ridges, absence of a chin, low height of the skull. Height – 1.5 m.
An upright position, although a less stable gait on bent legs. There is no direct evidence that Pithecanthropus made tools, since no remains of a lithic industry have been found with him.
The next link in human development was Sinanthropus. Due to the fact that his first remains were found in China, he was called “Chinese man” (from the Latin “Sina” - China and the Greek “anthropos” - man).
Sinanthropus lived 500-200 thousand years ago.
Discovered in 1927 in the Zhoukoudian Cave near Beijing, China. After the first discovery, large-scale research was carried out in the cave, as a result of which the bones of approximately 40 individuals were discovered over 10 years.
The value of the find is that the remains of both adult men and women, as well as children, were discovered.
Height is approximately 1.5 m, the structure of the limbs and torso is similar to modern ones. Straightened body position when walking.
Stone products are made mainly from sandstone, quartz, and also some quartzite, volcanic rocks, hornfels and flint.
Sinanthropus hunted mainly deer.
Of the animal bones found in the cave, 70% belong to deer. He widely used and knew how to maintain fire - a thick layer of ash, up to 6-7 m thick, was discovered in the cave.
Pithecanthropus and Sinanthropus were scientifically called “humans erect.”
Next view ancient man is called Neanderthal. His remains were first found in Germany in the Neanderthal area. Where the remains were found: Europe, Middle East, Caucasus, Crimea, Central Asia.
The easternmost point of Neanderthal habitation is the Teshik-Tash cave in Uzbekistan.
His height was average, his build was thick, his body was slightly stooped, his forehead was steep, and his eyebrows prominent. Neanderthals lived 200-35 thousand years ago. They knew how to make tools from stone, wood, bone, they could make fire and use it for their
science Library. dissertations in social psychology
The appearance of man.
Humans belong to a group of animals called primates. Our earliest ancestors were small arboreal animals, a bit like modern tupai. They lived on Earth approximately 65 million years ago, during the era of the extinction of dinosaurs. About 50 million years ago, more highly organized animals of the same type appeared, such as monkeys.
Over time, the development of some groups of primates followed a special path, and this path led to the emergence of the first apes about 25 million years ago.
Today, most of the 180 different species of primates live in tropical or subtropical regions, but this was not always the case.
50 million years ago, the climate on Earth was much warmer, and the ancestors of modern apes lived over a much larger area. Their fossil remains have been found in the British Isles, North America and even as far south as the very tip of South America.
Chimpanzee-like creatures once lived in Europe and Asia. However, when the climate on Earth began to change, the primates that inhabited these territories gradually became extinct.
Modern tupai give us some insight into what early primates might have looked like.
Life in the trees.
Early primates quickly became skilled tree climbers.
To live in trees, you must first of all correctly judge the distance and cling tightly to the branches. The first task is solved by forward-facing eyes: this gives the animal binocular vision.
To solve the second problem, tenacious fingers are needed. Both of these properties are the most important distinguishing characteristics of primates. They all have fingers
The fingers on the hands are mobile, and the thumbs give the proper grip. Some apes, like humans, are also able to join the tips of the thumb and index finger to form the letter "o".
This type of grip is used for very delicate manipulations. More importantly, primates have developed a large “thinking” part of the brain that coordinates vision and hand movements.
How it all began
Today there is only one species of people: homo sapiens (“homo” is Latin for “man”, and “sapiens” is “thinking”).
However, scientists today believe that from the moment the first hominids (human-like animals) appeared on Earth in different time There were several different species of such creatures. Between 15 and 7 million years ago, Ramapithecus lived in Africa, Europe and Asia. They were ape-like animals, about 1.2 m tall, with a flat face and teeth similar to those of humans. They may have spent part of their lives on the open plains, foraging for food using sticks and stones.
Ramapithecus is probably one of the first hominids, but it does not appear to have been our direct ancestor. Today, scientists find in it more similarities with orangutans.
Our closest living relatives are the great apes.
Gorillas and chimpanzees live in forested areas of West and East Africa. Gibbons are found in the rain forests of Southeast Asia, and orangutans inhabit the rainforests of Kalimantan and Sumatra. Of these, gibbons are the least human-like.
Very useful thumbs.
Why are thumbs needed? Have a friend tape your thumbs to your palms so that you can't move them.
Now try to take an object with one hand, say, a pencil or a cup. Or try to hold as many objects as possible. You will very quickly see how important it is for all these manipulations to have a thumb separated from all the others.
"Southern Monkeys" from Africa
One of the earliest fossil finds associated with the “ape-man” is the skull of a child. It was dug up in 1924 near Taung, in what is now Botswana.
This skull had both ape and human features, and its owner was named Australopithecus afarensis. Since then, many other fossil remains of australopithecines ("southern apes") have been found. All findings indicate that the brain of these animals was not very large (about 500 cm’), and large molars were used for grinding plants and fruits.
Australopithecines were short (about 1.2 m in height). Some were dense and stocky in build, others were fragile and graceful. Some scientists believe that these were
males and females of the same species. Some people refer to them as various types Australopithecus. The "Southern Monkeys" are the subject of much debate and their origins are still unclear.
"Lucy", a "southern monkey", found in 1974
These are some fragments of the skull bones of Sinanthropus - one of the “straightened people”.
Scientists managed to assemble these fragments into a single whole and restore the complete skull of Sinanthropus. He had a supraorbital ridge, like apes, and a protruding jaw. There was a bony protrusion along the top of the skull, and at the back there was a thickening in the form of a kind of ridge. Both the skull and brain of Sinanthropus are larger than those of Homo habilis.
The story of "Lucy".
American anthropologist Doi Johansen made an outstanding discovery when he dug up the remains of a young female “southern monkey” in Ethiopia, just over 1 m tall. She was named “Lucy”. “Lucy”’s brain and teeth were like those of a monkey, but she probably walked on her crooked legs in an upright position. Before this discovery, scientists believed that the “southern apes” lived on Earth about 2 million years ago. However, the age of the remains of "Lucy" was determined to be approximately 3-3.6 million years.
This means that the “southern monkeys” appeared on the planet more than a million years earlier than previously thought.
"Skillful Man"
At the same time that the “southern apes” were roaming Africa, another group of homipiids was developing side by side with them.
They appeared a little later, about 2 million years ago. These were already the first real people, or “Habilids”. Perhaps their ancestors were more slender australopithecines. Homo haoilis (“handy man”) was about the same height as the “southern apes”, but had a larger brain - about 700 cm’.
We know that the “skillful man” used a whole set of tools, which included fragments of stones, cutting and chopping tools (like knives), scrapers, as well as “tools” for making new tools.
The missing synanthrope.
Sinanthropus is a type of homo erectus.
He lived in China about 500,000 years ago. In the 30s XX century Scientists have discovered a rich collection of fossil remains of this ancient man in a cave near Beijing.
In total, fragments of 45 skeletons were found, including pieces of 14 skulls, 14 lower jaws, 150 teeth, as well as bones of 14 children. In 1941, shortly before the war between America and Japan, it was decided to send these finds to America. Scientists did not want such a valuable cargo to fall into the hands of Japanese soldiers.
However, the bones never arrived at their destination. They disappeared without a trace on their way to the ship that was supposed to take them to safety. The location of the remains of Sinanthropus 110 is unknown to this day.
Here is a photograph of the “Piltdown Man” skull, discovered in Sussex, England, at the beginning of the 20th century.
Today it is recognized as one of the greatest hoaxes in the history of science.
Neanderthals.
Even before the last “straightened people” disappeared from the face of the Earth, another species of human beings appeared on it.
Homo sapiens (“thinking man”) first made itself known about 250,000 years ago. After another 180,000 years (that is, 70,000 years ago), Neanderthal man settled in Europe.
Compared to their predecessors, Neanderthals were larger in all respects, hiding a brain like that of modern man- 1330 cm’. We know a lot about Neanderthals.
They lived in a great era. glaciation, so they had to wear clothes made from animal skins and take shelter from the cold in the depths of caves. The average life expectancy for men was about 30 years, and for women 23 years. Many of them suffered from arthritis. Most were right-handed.
There are some indications that Neanderthals believed in an afterlife: they ceremoniously buried their dead and even laid flowers on their graves.
Hunters of ancient people
Louis Leakey (1903-1972), Mary Leakey (b.
1913) and their son Richard (b. 1944) discovered many fossil remains of ancient people in the Oldowan Gorge in Tanzania. Their first important discovery was the discovery of Australopithecus, nicknamed the “nutcracker.” Subsequently, they discovered the first “skilled man”, and also found the remains of several “straightened people”.
Lately, Richard Leakey has been excavating in other areas of Africa.
These unique fossilized prints were discovered by Mary Leakey in 1978 in Tanzania. Their age is estimated at 3.75 million years, and they were imprinted in a layer of volcanic mud and ash, which later hardened. The result was something like a “plaster cast” of the feet of our distant ancestors who went out for a walk - a kind of prehistoric “family picnic”.
The man who never existed.
Several skull fragments and a broken jawbone of an ancient man were discovered near Piltdown in Sussex, England. At that time, the find became a real sensation, but soon some experts began to be overcome by doubts. In 1953, the Piltdown bones were carefully examined to determine their age.
The result was unexpected. It turned out that the jaw bone belonged to an orangutan 500 years ago, and the skull belonged to an ordinary modern person. The bones were coated with a special coating, and the teeth were carefully filed to give them a prehistoric appearance. All this turned out to be a skillful fake. Piltdown Man went down in the history of science as a hoax, exposed only 40 years after it took place. The “joker” himself was never found.
Head of a Neanderthal man.
A look into the future.
At first, human evolution occurred very slowly.
It took almost 7 million years since the appearance of our ancient ancestors for humanity to reach the stage at which it learned to create the first cave paintings.
But as soon as the “thinking man” firmly established himself on Earth, all human abilities began to develop rapidly. In just 100,000 years separating us from the first rock paintings, man has become the dominant form of life on Earth. We even managed to leave our home planet and begin space exploration.
It is difficult to say what people will be like after 10,000 years, but it is possible. increase
It’s arrogant to say that they will change a lot. In general, we have changed a lot over the past 400 years, and even since the beginning of this century.
Today's soldier would hardly fit into knightly armor of the 15th century. The average height of a medieval warrior was 16 cm. Nowadays, the average height of British soldiers is 172 cm.
There is no way the current supermodel could squeeze into the dress that her great-great-grandmother wore. Even if she managed to bring her waist to 45cm, like her Victorian relative, she would still be 30cm taller! If our evolution continues in the same direction as it has so far, our faces will become increasingly flatter and our lower jaws will become smaller.
Our brain will become larger, and we ourselves will most likely grow up. Well, because many of us. prefer a sedentary lifestyle, it is possible that our, so to speak, lower body will also increase!
As the Great Ice Age came to an end, modern people began to transition to a new way of life. Over time, they began to found settlements where large communities arose.
The dawn of civilization was approaching. 10,000 years ago there were only about 10 million people in the entire world. However, around 4,000 years ago their numbers began to increase rapidly. By 55 BC, when Julius Caesar invaded the British Isles, the world population had reached 300 million. Today it is already 4 billion and continues to grow.
The “southern apes” may have already used stones and bones as tools, but the “skillful people” were the first to learn how to make these tools.
A piece of stone, clamped between the thumb and all other fingers, served as a good cutting tool. The flatter stones were probably used to scrape meat from bones.
Tools with sharp edges were made using stone chippers. Homo erectus invented more modern tools: they were made from flint fragments. Even more subtle “tools” were created by Neanderthals. They processed flint fragments using other stone tools, which they held with two fingers - the thumb and forefinger.
"A cut above."
Recent studies have shown that our ancestors switched to upright walking, that is, walking on two legs, probably in order to avoid overheating.
On the hot African plains 4 million years ago, walking on two legs gave them a number of advantages. For a person in an upright position, the sun's rays fell vertically on his head, instead of “frying” his back. Because the top of the head has much less surface exposed to the sun than the back, our ancestors should have been less likely to overheat.
This means they sweated less, and therefore needed less water to survive. This allowed ancient people to become “head and shoulders above” other animals in the struggle for existence.
This is what scientists believe our long-vanished relatives looked like.
As you can see, our ancestors gradually became taller and the further they went, the less they looked like monkeys.
Where should the hair be?
The transition to upright walking had other important consequences. For example, the bipedal animal no longer needed thick hair, which protected other inhabitants of the savannas from the merciless rays of the sun that fell on their backs. As a result, with the exception of the hair that covered the part of our ancestors’ body most exposed to the sun’s heat - namely the head - they turned into the notorious “naked monkeys”.
Beneficial coolness
Having started to move on two yogas, the ancient people seemed to have opened another extremely important “evolutionary door”.
In an upright position, a much larger part of the animal’s body moves away from the hot soil, and therefore from the heat that it emits.
As a result, the body and head with the brain it contains overheat significantly less than if they were located closer to the ground. The cool wind, usually blowing 1-2 m above the ground, provided additional cooling of the body.
When scientists created powerful supercomputers, they had to equip them special system cooling. After all, large computers work very intensively and generate a huge amount of heat.
It must be removed to prevent the computer from overheating. The same thing happens with the brain. By switching to upright walking, our ancestors thereby moved their own brains to a cooler environment, and this, combined with a very effective “cooling system,” allowed the brain to develop into a larger and more active one.
The man who came in from the cold
September 19, 1991
a man whose age is 5300 years has returned to our world. Two tourists walking in the Austrian Alps suddenly came across the body of a man sticking out of the ice.
There were scraps of clothing on the body, shoes on the feet, a quiver with two arrows, an axe, a flint for striking fire, a small flint dagger, something like a bag or backpack, a set of needles and a lot of hunting equipment.
The Ice Man is the oldest corpse ever found. He lived on Earth almost 1000 years before the Egyptians began building their pyramids, and 3000 years before the first Romans appeared.
| Origin and development of man |
Today in the world people do not have a common opinion about the origin of man. Some, including teachers in school natural history classes, are inclined to trust Darwin’s assumptions that man descended from our smaller brothers, primates, and, accordingly, his physical and psychological development occurs in a similar way to that of representatives of primates.
Some believe that man was created by God in his own image and likeness, and his development occurs according to the command and understanding “from above.”
And there are those who are inclined to assume that the universe is the homeland of man. In this short article we will try to consider the most common versions today about the origin and development of man.
So, according to the first, and quite widespread theory today, the origin and development of man originates from anthropoid primates, or, more simply, from monkeys.
This theory, known to everyone from school, was created and voiced for the first time by the great Darwin.
According to his version, thanks to the natural mutation of the australopithecus, or, in other words, the southern upright walking monkeys, and the development of their brain, the ancestor of modern man, the Neanderthal, appeared. Who subsequently, thanks to his work and the development of his brain, reached the stage of modern man.
This theory can be confirmed by various archaeological finds and modern scientific understanding of the development of the human brain.
There are many people today who connect the origin and development of man with the Almighty God. According to their assumption, as mentioned earlier, humanity was created by God, and its development occurs according to God’s laws and according to his understanding.
To support their version, these people cite various miracles, which, in their opinion, occur due to the intervention of God.
The most famous such evidence cited by adherents of this theory is the descent of the Holy Fire in Jerusalem, various bleeding icons in different churches of the world, and others.
To prove their theory, they often cite various “miraculous” healings of seemingly hopelessly ill people. The highest degree of human development, in their opinion, can be considered his entry into the kingdom of God.
There are quite a few people nowadays who firmly believe that the origin and development of man is inextricably linked with UFOs.
According to adherents of this theory, man owes his appearance on earth to aliens from other planets. According to the simplest version of their theory, a person is a descendant of aliens who flew to our earth in prehistoric times. And they watch its development from above, sometimes correcting what is happening on earth.
Well, perhaps the most fantastic of the versions given here will be the theory that the origin of man is connected with a spatial anomaly and is subject to its law of existence.
According to this hypothesis, intelligent beings, like humans, can appear and develop on any of the planets suitable for life, thanks to the cosmic laws of existence, not yet known to us.
Finally, it is worth saying that, in my opinion, the most proven and worth further studying is the theory of Evolution, or in other words, Darwin’s theory, despite all the arguments and, as it seems to them, evidence brought by its opponents.
What do you think?
Article “The Origin and Development of Man” from the section | Human Development |
Question 1. How did the activities of primitive man affect the environment?
Already more than 1 million years ago, Pithecanthropus obtained food by hunting. Neanderthals used a variety of stone tools for hunting and hunted their prey collectively. Cro-Magnons created snares, spears, spear throwers and other devices. However, all this did not make serious changes to the structure of ecosystems. Human impact on nature intensified during the Neolithic era, when cattle breeding and agriculture began to become increasingly important. Man began to destroy natural communities, without, however, yet having a global impact on the bio-sphere as a whole. Nevertheless, unregulated grazing of livestock, as well as clearing of forests for fuel and crops, already at that time changed the state of many natural ecosystems.
Question 2. To what period of development of human society does the origin of agricultural production belong?
Agriculture appeared after the end of glaciation in the Neolithic era (New Stone Age). This period is usually dated to 8-3 millennia BC. e. At this time, man domesticated several species of animals (first the dog, then the ungulates - pig, sheep, goat, cow, horse) and began to cultivate the first cultivated plants (wheat, barley, legumes).
Question 3. Name the reasons for the possible occurrence of water shortages in a number of areas of the world.
A lack of water can arise as a result of various human actions. With the construction of dams and changes in river beds, a redistribution of water flow occurs: some territories are flooded, others begin to suffer from drought. Increased evaporation from the surface of reservoirs leads not only to the formation of water shortages, but also changes the climate of entire regions. Irrigated agriculture depletes surface and soil water supplies. Deforestation on the border with deserts contributes to the formation of new territories with a lack of water. Finally, the reasons may be high population density, excessive industrial needs, as well as pollution of existing water supplies.
Question 4. How does the destruction of forests affect the state of the bio-sphere?Material from the site
Deforestation catastrophically worsens the condition of the biosphere as a whole. As a result of logging, surface water flow increases, which increases the likelihood of floods. Intensive soil erosion begins, leading to the destruction of the fertile layer and pollution of water bodies with organic substances, water blooms, etc. Deforestation increases the amount of carbon dioxide in the atmosphere, which is one of the factors increasing the greenhouse effect; the amount of dust in the air is growing; The danger of a gradual decrease in the amount of oxygen is also relevant.
Cutting down large trees destroys established forest ecosystems. They are replaced by much less productive biocenoses: small forests, swamps, semi-deserts. At the same time, dozens of species of plants and animals may disappear irrevocably.
Currently, the main “lungs” of our planet are the equatorial tropical forests and taiga. Both of these groups of eco-systems are in extreme need careful attitude and security.
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