The origin of mankind is a difficult problem to understand. The earliest written records appeared 5000~6000 years ago, before which we knew almost nothing. 187 1 year, Darwin first put forward the conjecture that human beings originated in Africa in his book The Origin of Human Beings, but there was no actual evidence at that time. It was not until nearly fifty years later that archaeologists discovered ancient human fossils in Africa that this conjecture was basically confirmed. (At present, the earliest human fossil, "Lucy" 3.2 million years ago, has been found in Ethiopia. However, the information available in archaeological excavations is very limited, and myths and legends are even more unreliable. Until recent decades, molecular anthropology has risen, using genes to analyze human origin, national evolution and other issues, combined with archaeological research, and made breakthrough progress, but there are still many controversies and mysteries.
The mainstream view is that human beings evolved from African apes about 7 million to 5 million years ago. Early humans had more than one species and walked out of Africa more than once. Instead, the story of "the back waves of the Yangtze River push the front waves, and the front waves die on the beach" has been staged many times. The earliest hominids who walked out of Africa were different species from today's human beings. They expanded from Africa to Eurasia millions of years ago-for example, Homo erectus (formerly known as ape-man, Peking man and Yuanmou man) lived in Asia and Africa 2 million to 200,000 years ago, and Neanderthals lived in Europe 400,000 to 35,000 years ago-but these races later became extinct, and today's human beings are not their descendants.
Homo sapiens appeared in Africa about 400,000 ~ 250,000 years ago, and evolved into anatomically modern people (called late Homo sapiens) about 250,000 ~ 6,543.8+0.5 million years ago. 1.20 thousand years ago, Homo sapiens began to go out of Africa and enter the two river basins, but it seems to have died out 80 thousand years ago. About 60,000 years ago, Homo sapiens went out of Africa again and successfully spread to all parts of the world: they traveled along the northern shore of the Indian Ocean (the sea level at that time was lower than it is now 100 meters, and the advance route of Homo sapiens was probably below today's sea level), arrived in Australia through Southeast Asia, then entered southern China about 50,000 years ago, entered Europe about 40,000 years ago, arrived in Japan about 30,000 years ago, and crossed the Bering Continental Bridge, which is even more incredible. In this magnificent expansion process, Homo sapiens wiped out all other species it encountered, so all human beings living in the world today are Homo sapiens. -No human fossils from 65438+ 10,000 to 40,000 years ago have been found in China. It is likely that Homo erectus was extinct before Homo sapiens arrived. In Europe, Neanderthals and Homo sapiens existed for some time. It is possible that Homo sapiens exterminated Neanderthals. (However, a new study published on 20 10 shows that modern Homo sapiens genes were mixed with a few Neanderthals genes, indicating that Homo sapiens had a small-scale hybrid with Neanderthals after leaving Africa. )
Gene research
Archaeological excavation can confirm the time when Homo sapiens arrived in various places, but we need more tools to study the racial evolution of Homo sapiens in the process of expansion. Until a few decades ago, people used skin color, hair and appearance as the main basis to distinguish human races, but through genetic research, we found that this was not the case. Appearance features are mainly formed to adapt to the natural environment in different regions, and can not accurately reflect the differences between races: for example, Indians with brown skin may be very close to European whites, while the genes of Han people in China and Mongolians with yellow skin are actually far apart.
There are two main methods to study genes in molecular anthropology: mitochondrial DNA(mtDNA) and Y-DNA. The former is passed down from mother to daughter, and the latter is passed down from generation to generation. The study of mtDNA shows that all the genes of women today can be traced back to an African woman ("Mitochondrial Eve") 654.38+05 thousand years ago, while the study of Y-DNA shows that all the genes of men can be traced back to an African man ("Y chromosome Adam") 60 thousand years ago. Starting from them, according to the mutation information in DNA, the existing human beings can be divided into different types. However, it is worth noting that in many places, the distribution of mitochondrial types (maternal inheritance) is not consistent with the distribution of Y chromosomes (paternal inheritance). It can be speculated that this is due to the racial substitution in the process of human expansion. When the powerful race defeated the weak race, they killed all the males of the losers, while the female part remained, thus causing this phenomenon. Therefore, the distribution of Y-DNA can better reflect the result of racial expansion.
The researchers used letters to indicate the different types of Y-DNA: the first ones that arrived in East Asia were type C (Australian aborigines, ancestors of Tunguska-Mongols in Northeast Asia, and a few of them arrived in western North America) and type D (ancestors of Andaman in Indonesia, Ainu in Japan and some Tibetans). They used to occupy a vast world, but now only some ruins are left, which are distributed in remote and wild places, because another group of people who appeared later, people with lighter skin and taller bodies, defeated them. These latecomers originated from F-type which appeared in South Asia about 45,000 years ago, and gradually spread to almost all continents except Africa, and were further divided into more types, among which the main types are: J-type is the ancestor of the Semites (Arabs and Jews) in the Middle East; Type O is the ancestor of most ethnic groups in East Asia, Southeast Asia and the South Island of the Pacific Ocean (among them, the Han, Miao and Yao are mainly O3, while the proportion of O2 in Japan and South Korea is relatively high). Q type is the mainstream of American Indians, and a small amount exists in Mongolia and Siberia; R-type is a primitive Indo-European language family, and its descendants include most European and American whites, Iranians and some Indians today. In Africa, the hometown of mankind, there are still ancient type A (Bushmen) and type B (Pygmies), but the later type E became the mainstream and differentiated into many different branches. This means that the races on other continents have the same ancestors as the existing A/B/E Africans, but they did not evolve from these African races.
Through such repeated differentiation, expansion and substitution, primitive humans were basically formed 6.5438+0.2 million years ago. It is worth mentioning that Mongolians are mainly of type C, plus a small amount of other types of mixed blood, so it is inaccurate to define Han people as Mongolians in the past, and the gap between Han people and Mongolian ancients is even greater than that between them and Europeans.
Agricultural revolution
At the same time of human evolution, the earth's environment itself has experienced vicissitudes. About 2.6 million years ago (when primitive humans appeared), the earth entered a great ice age, which was called Quaternary in geology. Generally speaking, the climate of Quaternary is colder than most periods in the history of the earth, and its interior can be divided into relatively cold glacial periods and relatively warm interglacial periods, which appear alternately. The last ice age ended 654.38+200,000 years ago. From then to today, it was a warm interglacial period, which was called Holocene in geology.
In the early Holocene, Homo sapiens had become the only human being on the earth and had spread to all continents except Antarctica. But at this time, their production mode is no different from that of early humans, and they still focus on gathering and hunting. We speculate that the gathering-hunting method can't support a large number of people to live together, so the population at this time is very small and often migrates for food. With global warming, great changes have taken place in the natural environment and the distribution of animals and plants, and human beings have also improved their production methods to adapt to the new environment, thus producing the first large-scale technological revolution. The obvious sign of archaeology is that rough stone tools were replaced by finely polished stone tools, that is, from Paleolithic to Neolithic, but more importantly, wise men invented agriculture and began to carry out large-scale transformation of the natural environment.
Agriculture did not originate in a single place, but was independently produced in many areas. The Middle East is probably the earliest agricultural birthplace, and crops such as barley, wheat and lentils were planted about 1. 1 10,000 years ago. In East Asia, rice was planted in the Yangtze River valley in China about 6,543,800 years ago, and millet was planted in the Yellow River valley about 8,000 years ago. In America, Indians began to grow potatoes about 7000 years ago, but the domestication of corn is much more complicated, and it may take a long time to gradually cultivate it into what it is now.
While planting plants, human beings have domesticated many kinds of animals. Dogs are man's best friends, and they were domesticated even earlier than 1.4 million years ago. Goats and sheep were domesticated in Iran about 654.38 million years ago, and were introduced to the West and China respectively. (In China, the earliest sheep breeder is a western nation, known as Qiang people, or "sheep breeder". Domestication of cattle and pigs may have multiple origins, which occurred independently in the Middle East and China. Domestic cats were domesticated quite late, about 5,000 years ago in ancient Egypt-some people think that cats have not been fully domesticated.
The agricultural revolution not only changed the mode of production of mankind, but also profoundly changed the social form of mankind. The agricultural population settled around cultivated land, the population increased, large villages and even city-states developed, and gradually entered the era of civilization. Comparatively speaking, the agricultural output in warm areas is higher, which can carry more people to settle down and make the civilization more developed. In cold areas, the mixed agriculture of agriculture and animal husbandry is adopted, with less population, more frequent migration and slower development of civilization. In addition, there are still a few areas that retain relatively primitive fishing and hunting culture.
Indo-European expansion
About 4000 BC (about 6000 years ago), primitive Indo-Europeans (type R) domesticated horses in the grasslands of Eastern Europe. This incident has had a far-reaching impact on the human world, because before the invention of guns, cars and tanks, horses were the most powerful biological weapons and the fastest land transportation. With horses, Indo-Europeans, although underdeveloped in civilization (far from Sumerians in the period), had strong expansion ability, and quickly expanded to almost all areas suitable for survival and access in the early stage of human civilization. At the same time, due to the frequent communication between races, the spread of civilization has also been greatly accelerated, and Indo-European descendants have developed into the most powerful ethnic group in the world in this process, until today.
About 3000 years ago, some Indo-Europeans (R 1b type) began to expand to the west of Europe. At this time, the early agricultural population had settled in western Europe, but Indo-Europeans seemed to replace them soon. Indo-Europeans marched in three ways: all the way southwest to the Greek peninsula and evolved into ancient Greeks (Mycenae); All the way west to the middle reaches of the Danube, it divides into two tributaries. One entered Italy from the southern foothills of the Alps and became a Latin. The other bypassed the Alps from the north, entered Gaul and Britain and became a Celtic. All the way to the Baltic coast, it is divided into two parts, the west is called Germanic and the east is called Slavic. This is the origin of all ethnic groups in Europe today.
From about 2500 to 2000, Indo-Europeans further invented horse-drawn chariots, and then extended to Asia. About BC 1900, a branch of Indo-European language family entered Anatolia and became a Hittite. At about the same time, another part of Indo-Europeans (R 1a type) who migrated eastward set out from the northern Caspian Sea and went deep into Asia. Under the power of chariots, they are invincible in Central Asia. All the way (Aryans) conquered Afghanistan, Pakistan and northern India, and the other conquered the Iranian plateau. However, the other road (Tuholo people) entered China from Altai area, and was stopped by local residents and stopped in Tianshan area. Horses and chariots were also introduced into China.
In this wave, almost all the central and western parts of Eurasia were occupied by Indo-European nations, and ancient India, Babylonian civilization and Minoan civilization were all conquered. In areas conquered by ancient civilizations, settled Indo-European nations learned from ancient civilizations and developed a brighter new generation of civilizations. On the other hand, Indo-Europeans who stayed in their hometown of Eastern Europe fell behind, and they were called Skeptics (or Serbs).