The stages of human evolution
The stages of human evolution
Scientists say that modern man did not evolve from modern apes, which are characterized by narrow specialization (adaptation to a strictly defined lifestyle in the rainforest), and from extinct several million years ago a highly organized animals dryopithecus. The process of human evolution is very long, its basic steps are presented in scheme.
According to paleontological findings (fossils), about 30 million years ago appeared on Earth the ancient primates parapetti, who lived in open spaces and in the trees. Their jaws and teeth were like the jaws and teeth of great apes. Parapetti gave rise to the modern Gibbons and orangutans, as well as an extinct branch of dryopithecus. The latest in its development was divided into three lines: one of them led to the modern gorilla, and the other to chimps, and the third to the Australopithecus and then to the man. The relationship of Tripitaka with a person established on the basis of studying the structure of its jaw and teeth that were discovered in 1856 in France.
The most important stage in the transformation APE-like animals in ancient people was the emergence of bipedalism. In connection with climate change and forests izrazavanje came the transition from arboreal to terrestrial lifestyle; to better observe the terrain, where human ancestors had a lot of enemies, they had to stand on the hind legs. In the future, natural selection has developed and secured the upright posture, and, as a consequence, the hands are freed from the functions of support and movement. So there was a Australopithecus — the genus to which the hominids (family people).
The Australopithecines — highly evolved bipedal primates that used items of natural origin as instruments (hence, Australopithecus cannot be considered to be people). Fossil remains of Australopithecus first discovered in 1924 in South Africa. They were the height of a chimpanzee and weighing about 50 kg, the volume of the brain reached 500 cm3 — on the basis of Australopithecus is closer to man than any of the fossil and modern apes.
The pelvis and the position of the head was similar to those of man, which testifies to the erect position of the body. They lived about 9 million years ago in the open steppe, and feed on vegetable and animal food. Instruments of their labour were stones, bones, sticks, jaw, without traces of artificial processing.
The skilled person
Not with a narrow specialization of the General structure, the Australopithecines gave rise to the more advanced form, called Homo habilis — Homo habilis. Fossil remains it was discovered in 1959 in Tanzania. Their age estimated at some 2 million years. The growth of this creature reached 150 cm brain volume was 100 cm3 larger than those of Australopithecines, the teeth of a human type, the phalanges as in humans, is tapered.
Although it combined the characteristics both monkeys and humans, the transition of this creature to the manufacture of pebble tools (well-dressed stone) indicates the appearance of his employment. They can catch animals, throw stones and perform other actions. The pile of bones held together with fossil remains of Homo habilis, evidence of the Ute that meat became a regular part of their diet. These hominids used a rough stone tools.
Homo erectus — Homo erectus. the view that is believed to have occurred. His age of 1.5 million years. His jaw, teeth and brow ridges were still massive, but the volume of the brain in some individuals was the same as modern humans.
Some Homo erectus bones found in caves, suggesting that his permanent home. In addition to animal bones and a rather well-crafted stone tools in some caves discovered heaps of charcoal and burnt bones, so that apparently at this time the Australopithecines, already learned to make fire.
This stage of hominid evolution coincides with the settlement of immigrants from Africa other colder areas. To withstand cold winters without developing a complex of behaviors or technical skills that would be impossible. Scientists suggest that pre-human brain of Homo erectus was able to find social and technical solutions (fire, clothing, the stock of poor and living together in caves) problems associated with the need to survive in the cold of winter. Thus, all fossil hominids, particularly Australopithecus are considered as mammals.
The evolution of the physical characteristics of the first people, including modern man, covers three stages: ancient people or arhantrop; the ancients, or palaeoanthropes; modern people, or neoanthrope.
The first representative arhantrop — Pithecanthropus (Japanese people) — APE-man, upright. His bones found on the island of Java (Indonesia) in 1891, Originally his age was determined equal to 1 million years, but according to a more accurate modern assessment, he was a little more than 400 thousand years. The growth of Pithecanthropus was about 170 cm, the cranial capacity of 900 cm3.
Later there was Peking man (Chinese man). Its numerous remains found in the period 1927 to 1963 in a cave near Beijing. Is being used fire and stone tools izgotovleno. This group of ancient people date back and Heidelberg man.
The palaeoanthropes — Neanderthals appeared in place of argatroban. 250-100 million years ago, they were widely settled in Europe. Africa. The front and South Asia. The Neanderthals made a variety of stone tools: hand-axes, scrapers, pointed tips; used fire, rough clothes. The volume of their brain increased 1400 cm3.
Features of the structure of the lower jaw show that they had rudimentary speech. They lived in groups of 50-100 individuals, and during the advance of glaciers used caves, driving them from wild animals.
Neoanthrope and reasonable man
Neanderthals replaced modern humans — CRO-magnons — or neoanthrope. They appeared about 50 thousand years ago (fossil remains found in 1868 in France). The CRO-magnons form a single genus n species Homo Sapiens – the person reasonable. They completely smoothed out the simian features on the lower jaw had a distinctive chin projection, indicating their ability to articulate speech and the art of making a variety of implements of stone, bone and horn CRO-magnons have gone far ahead in comparison with Neanderthals.
They domesticated animals and began to develop agriculture, which allowed to get rid of hunger and to produce a variety of food. Unlike its predecessors the evolution of a CRO-magnon passed under the great influence of social factors (team building, mutual support, improvement of work, higher level thinking).
The emergence of CRO-magnon is the final stage of formation of man of modern type. To replace the primitive human herd came first tribal system, completing the development of human society, further progress of which was to determine the socio-economic laws.
The human race
Living humanity is divided into a number of groups called races.
The human race
is a historically developed community of people with common origin and similarity of morphological characters, as well as hereditary physical traits: facial structure, body proportions, skin color, shape and hair color.
These signs of modern humanity is divided into three main races: Caucasoid, Negroid and Mongoloid. Each of them has its own morphological features, but it's all external, secondary characteristics.
Especially components of human nature such as consciousness, labor activity, speech, ability to learn and conquer nature, common in all races that refutes the claims of the ideologists of the racist about "superior" Nations and races.
The children of Negroes, brought along with the Europeans, not inferior to them in intelligence and giftedness. It is known that the centers of civilization 3-2 thousand years BC were in Asia and Africa, and Europe at this time was in a state of barbarism. Therefore, the level of culture does not depend on the biological characteristics and socio-economic conditions in which people live.
Thus, approval of the reactionary scientists about the superiority of some races and inferiority of the other are unfounded and pseudoscientific. They were created to justify wars of conquest, the plunder of the colonies n of racial discrimination.
The races of man cannot be mixed with such social organizations as the nation and the nation that was formed not by biological principle, and based on the stability of General speech, territory, economic and cultural life formed historically.
People in its history, has refused to obey the biological laws of natural selection, its adaptation to life in different conditions occurs by active alteration. However, these conditions are to some extent still have an impact on the human body.
The results of such influence is visible on several examples: in the peculiarities of the digestive processes the reindeer herders of the Arctic, consuming a lot of meat, the inhabitants of South-East Asia, the diet which consists mainly of rice; in an increased number of erythrocytes in the blood of the highlanders compared with the blood of the inhabitants of the plains; in skin pigmentation of the inhabitants of the tropics, distinguish them from the white skin of northerners.
After completion of the formation of modern man the action of natural selection has not stopped completely. As a result, in some regions of the globe a person has developed resistance to some diseases. So, the Europeans measles is much more easier than the peoples of Polynesia who are faced with this infection after colonization of the Islands by immigrants from Europe.
In Central Asia, in human rare blood group 0, but the higher the frequency of group B. it was Found that this is due to the epidemic of plague that occurred in the past. All these facts prove that in human society there is a biological selection on the basis of which was formed of the human race, people, nation. But the growing independence of man from the environment almost suspended biological evolution.