How is human life formed? The origin and formation of life.

Scientists believe that the first step in the origin of life is that a self-replicating chemical substance-which later developed into DNA-is surrounded by a thin film called bubbles. Charles Appel, in cooperation with his colleagues, has been able to make such bubbles in fresh water by using the material components of the early earth, but the same result cannot be obtained in a salt water environment. According to the report, the research results question the theory of ocean origin, but it is somewhat similar to Darwin's theory.

A century ago, Darwin speculated in his personal letters that life originated from "a small pond rich in organic salts of ammonia and phosphorus, light, heat, electricity and other related substances." After the formation of human life, most scientists agree that human ancestors originated in Africa, but hold different opinions on the development process of human beings after they first left Africa. American scientists recently put forward a new viewpoint of human evolution, thinking that human beings have gone out of Africa three times.

This is the first time that mankind has walked out of Africa. It has been suggested that after Homo erectus left Africa, modern people rose in different parts of the world. However, some people think that about 50 thousand years ago, another group of people went out of Africa, completely replacing the early residents of Eurasia. Allen templeton, a scientist at the University of Washington in the United States, suggested that both of the above viewpoints may have some truth, and the fact may be somewhere in between. African immigrants in the later period had a great influence on human genetic characteristics, but they realized it in the form of intermarriage, rather than completely replacing the original residents by force.

4. After Homo erectus left Africa, there was another large-scale migration wave from Africa 400,000 to 800,000 years ago, and the third time occurred about 654.38 million+years ago. He also found a tendency to return to Africa from Asia. Some scientists support Templeton's view. However, some people are skeptical that his chromosome analysis method is flawed. Some archaeologists say that there is a lack of archaeological evidence consistent with it.

5. However, another important discovery makes a better annotation for mankind to go out of Africa, because scientists found that a Greek woman and Native Americans have the same ancestor, and the ancestor "Eve" traced back to mankind may be African black! The special program "The Real Eve" of Discovery Channel traces the whole process of human blood relationship, just like a living science detective story. The world's top scientists, through cutting-edge scientific and technological research, have proved that part of human mitochondrial DNA today is the same as that of an African woman 6.5438+0.5 million years ago. This African woman named Eve was not the only one at that time, but she had the only surviving and most successful mitochondrial DNA.