The direct evidence for studying the origin of human beings comes from fossils. Anthropologists use comparative anatomy to study all kinds of ancient ape fossils and human fossils, determine their relative and absolute ages, thus determine the age of human fossils, and roughly divide the evolutionary history of human beings into several stages. Geneticists, on the other hand, use the methods of biochemistry and molecular biology to study the differences and variation speed of protein and deoxyribonucleic acid (DNA) among modern humans, various apes and other higher primates, so as to calculate their respective origins and differentiation ages. At present, it is generally believed in academic circles that the time when apes became human ancestors was 7 million years ago.
Judging from the discovered human fossils, human evolution can be roughly divided into the following four stages:
(1) Australopithecus stage. The Australopithecus found lived from 4.4 million years ago to 6.5438+0 million years ago. According to the study on the anatomical characteristics of fossils, the most important feature of Australopithecus is that it can walk upright on both feet, which is different from apes.
(2) the stage of capable people. /kloc-fossils of homo habilis have been found in Tanzania and Kenya in East Africa since 0/960. The earliest possible life existed 6.5438+0.9 million years ago. An able person is classified as an able person below the human subject. Homo habilis has a bigger brain than Australopithecus, and can make tools (stone tools) from stones, and then gradually evolve into Homo erectus.
(3) Homo erectus. Homo erectus belongs to Homo erectus in classification, referred to as Homo erectus, commonly known as Homo erectus. Homo erectus fossils were first discovered in Java, Indonesia in 189 1. At that time, there was also a debate about whether people were apes or not. It was not until the 1920s that Peking man's fossils and stone tools were discovered in Zhoukoudian, Beijing, that Homo erectus was established in the history of human evolution. Homo erectus lived about 6.5438+0.7 million years ago to over 200,000 years ago. So far, homo erectus fossils have been found in Asia, Africa and Europe.
(4) Homo sapiens stage. Homo sapiens is generally divided into early homo sapiens (ancient homo sapiens) and late homo sapiens (modern man). Early Homo sapiens lived from 200,000 years ago to over 654.38 million years ago. The survival age of late Homo sapiens began about 654.38 million years ago. Its anatomical structure is basically similar to that of modern people, so it is also called modern people in anatomical structure.
According to the evidence of human fossils found so far, Australopithecus is the earliest known human.
The stage of the development of human body shape
summary
After the transition from apes to humans, human physique continued to develop. For a long time, people divided this development process into three stages: ape-man, ancients and newcomers. Due to the continuous enrichment of fossil materials and the deepening of people's understanding, this staging method is no longer suitable. At present, foreign scholars mainly adopt two stages. Firstly, it is divided into three stages: Australopithecus, Homo erectus and Homo sapiens. Homo sapiens can be divided into early homo sapiens and modern homo sapiens. The disadvantage of this division is that Australopithecus, who can't make tools, and the number 1470 are grouped together. The other is divided into four stages: earliest human (or earliest genus), Homo erectus, early Homo sapiens and modern Homo sapiens. China scholars also put forward the division of four stages, namely, early Homo sapiens, late Homo erectus, early Homo sapiens and late Homo sapiens. The "early ape-man" stage is equivalent to the "earliest human (genus)" stage proposed by foreign scholars. Although there are not many fossil materials found before Homo erectus, it is still a more appropriate way to classify them as a separate stage to distinguish them from Australopithecus and Homo erectus.
The earliest human beings
1974 Since then, British scholar M.D. Leakey has discovered human fossils in Letoril stratum in Letori, Tanzania. In addition to the bones of some five-year-old children, some adult jaw fragments and teeth were found. It was between 3.8 million and 3.6 million years ago. 1978 human footprints left in volcanic tuff found in Letoril stratum belong to two people, one big and one small. Footprints have a raised arch, a round heel, and the big toe is juxtaposed with the other four toes in front of the foot. These are all human characteristics, so some scholars classify them into a genus. But no stone tools were found in the same stratum. Johnson and others believe that the fossils found in the toril formation are Australopithecus afarensis, not real humans. 1972, a man's skull with the number KNM-ER 1470 was found in Kubifra on the east bank of Lake Turkana in Kenya, East Africa, dated 2.9 million years ago. The brain volume is about 775 ml. The skull has no prominent brow ridge like Homo erectus, so its position in the evolutionary system is still controversial. Paleolithic was found at the height of 1968 KNM-ER 1470. At that time, it was determined to be 26 1 0,000 years ago, and it was renamed as 1 975 and 1 976 respectively. Since 1960, some human fossils have been found in Odoje Yi Canyon. 1964 was rated as "capable person". Its brain capacity is about 680 ml, and its hand bones and foot bones are similar to those of modern people. Many gravel tools, mainly chopping tools, were found on the horizon where homo habilis was found. In addition, a circle of stones was found, presumably a simple residence built by able people. The age of living is 6.5438+0.8 million years ago. Mosoketo people found in Java were originally called Mosoketo apes. In recent years, some people think that it may belong to homo habilis, and its date is about 1.9 million years ago.
Homo erectus
In China, it is customary to call them "ape-men". The age of survival is about 6.5438+0.7 million years ago or 6.5438+0.5 million years ago to 200,000 or 300,000 years ago. The geological age belongs to the late Early Pleistocene to the Middle Pleistocene. Its brain volume is 775 ~ 1400 ml. The earliest Homo erectus was found in 189 1 year. Dutch military doctor E. Dubois found a skull and a tooth near Trinier, Central Java, and a femur and a molar in the same stratum the following year. The skull is very thick, the brow ridge is prominent, and the skull is low and flat, which has the characteristics of apes, but the leg bones are human-like and suitable for walking upright, so it was named "Homo erectus" at that time. Fossils of Homo erectus were found in Asia, Africa and Europe. China has Beijingers, Lantian people and Yuanmou people; In Africa, there are Kenyan KNM-ER3733, KNM-ER992, KNM-ER3228, Tanzanian Odoje I Canyon OH9, OH28, Algerian and Moroccan Mauritanians. There are Heidelberg people in Germany in Europe. In addition, in recent years, Vitshalos in Hungary, Plesiler in Czechoslovakia and Birchinsleben in Germany have also discovered ape-man fossils.
Early homo sapiens
Also known as the ancients or Neanderthals. Lived about 200 thousand to 300 thousand years ago. The geological age belongs to the late Pleistocene. The first thing that caught people's attention was a human skeleton found in a cave in the Neanderthal valley near Dü sseldorf, Germany 1856. It was named Neanderthal and its scientific name was changed to Homo sapiens subspecies Neanderthal. Fossils of early Homo sapiens have been found in Asia, Africa and Europe. The earliest survivors were Steinheimer in Germany and Swansecombe in Britain, about 250,000 years ago. Many scholars believe that they are in the transitional stage between Homo erectus and Neanderthals. Dali people found in Shaanxi Province of China also have this transitional nature. The physique of early Homo sapiens is close to that of modern people, but it still retains some original features, such as a more developed brow ridge, a low and inclined forehead, a more prominent jaw and an inconspicuous chin. The brain volume is about 1300 ~ 1750 ml, which is much larger than that of homo erectus and the brain tissue is more complicated. In the long-term labor process, human physique and wisdom have been further developed. At present, many anthropologists believe that early Homo sapiens can be divided into two types. One is "typical Neanderthals", found in Spain, France, Belgium, Germany and Italy. One is the "progressive Neanderthals", found in Lebanon, Israel and other places. Progressive Neanderthals had slightly smaller brains than typical Neanderthals, but their physique was closer to that of late Homo sapiens. It is generally believed that the progressive Neanderthals later developed into late Homo sapiens. Typical Neanderthals, some scholars think that they are an extinct branch in the process of human development, while others think that they are not extinct, but the ancestors of later Europeans.
Late homo sapiens
Also known as the newcomer, it appeared 40,000 years ago. The forehead of the skull bulges, the brow bone almost disappears, the jaw retreats and the chin is obvious. The body shape is not much different from that of modern people. The fossils found were distributed in Asia, Africa, Europe, the United States and Australia, indicating that all continents except Antarctica were inhabited at that time. Because 48,000-year-old human fossils were found in Southern California, some people think that humans arrived in America at least 50,000 years ago. But many scholars doubt the age of this human fossil. The earliest human fossils in Australia were found in Lake Mungo, 32,750 years ago, so the time when humans arrived in Australia from Asia may be 40,000 years ago. When the late Homo sapiens appeared, the modern race was also formed. At present, ethnic groups are divided into three categories, namely Mongols, Caucasians and blacks. There are other races in Australia, which are divided into four major races. There are several races under the big species. The factors of racial formation are extremely complicated, which are generally considered to be the result of long-term influence of natural and historical conditions.