Where did humans come from? This issue has been debated by historians, archaeologists and biologists in past. Before advent of molecular anthropology, many Chinese historians believed that China was also one of origins of man. However, with continuous development of science and technology, many people also realize that people can only have one origin, and it is absolutely impossible to have multiple origins. And voice of Asian origin theory is also decreasing.
In past, archaeologists have had two disputes about origin of man: theory of origin from one place and theory of origin from several places. Some origin proponents believe that Africa is one of places of origin of man, and Asia is also one of places of origin of man. However, according to basic theory of biology: different species descended from a common ancestor, and organisms of same species must also descend from one common ancestor. This is a rejection of theory of multi-local origin of people from basic principles, and origin of people must come from same ancestor. Currently, not all humans are reproductively isolated, while humans and all other species are reproductively isolated. It also shows that all people are related by blood.
In past, people judged origins of humans mainly based on ancient human fossils found underground. The human fossils found in Africa are largest on all continents of world. These fossils include various forest monkeys, land monkeys, ape-like people, anthropoids, orangutans and ancient people, as well as bones, various stone tools and bone tools. , and tombs. From 10,000 years ago to 10,000 years ago, a complete evolutionary chain was basically formed. Therefore, vast majority of archaeologists in world believe that Africa is birthplace of man. However, some scholars in Asia have also suggested that Yuanmou Man, Javanese Man, Peking Man, and other fossils also appeared in Asia. Many common people in China also believe that Yuanmou people are ancestors of Chinese. Therefore, one cannot rely solely on archeology.
In second half of 20th century, with development of human genetic engineering and molecular anthropology, people can finally make a connection between people by discovering human DNA. Through discovery of DNA samples from all over world, scientists have discovered that all humans in world share a common ancestor, and that ancestor lived 200,000 years ago. With exception of Africa, a common ancestor in other regions appeared approximately 70,000–50,000 years ago. Moreover, all people have mutations in African genes, and Africans do not have mutations in other continents. This means that humans originated in Africa and modern humans from other continents migrated to different parts of world around 70,000–10,000 years ago.
Because ancestors of modern humans originated in Africa 200,000 years ago and migrated to different parts of world over 50,000 years ago, so many fossils have been discovered around world hundreds of thousands of years ago and 1 million years ago. explain it? It turns out that all these ancient ape and human fossils migrated from Africa to different parts of world, but timing of migration is different. But about 100,000 years ago, Asian continent entered an ice age altogether. During this time, ancient humans that led to early migration to Eurasian continent largely died out. China had a blank period of human fossils from 100,000 to 50,000 years ago.
Of course, some ancient people survived. When ancestors of modern humans (late Homo sapiens) arrived on Eurasian continent, they encountered remaining Homo erectus and early Homo sapiens. As later Homo sapiens evolved further, they were able to replace these ancient humans. Of course, there will be some mixing situations. In 2010, scientists obtained complete Neanderthal genomic data, which proved that modern Eurasians have between 1% and 4% of Neanderthal genes, and size of modern human gene fragments shows a crossing time of about 50,000 years ago, which coincides with time when modern humans migrated from Africa.