If there is only one man and one woman left on the earth, how long will it take to recover to 7.5 billion people?

With the end of World War II and the improvement of medical level, the population on the earth is growing faster and faster. In the 1950s, the population on the earth was small, only over 2 billion. It's only been 70 years now, and the population of the earth has grown to 7.5 billion, with an average annual increase of nearly 80 million people, which is equivalent to the increase of the total population of Germany. The rapid growth of human beings has brought serious problems, such as food crisis, rampant diseases, ecological crisis and environment. According to the calculation of scientists, the ecological carrying capacity of the earth's population is only about 20 billion, which means that the population will reach the ecological carrying capacity of the earth's population in about 100 years. At that time, human beings may have to make interstellar migration to survive.

The Big Bang of the Earth's Population

Although there are 7.5 billion people on the earth, human beings have always wanted to know how the earliest humans on the earth gave birth to these 7.5 billion people. There are many fairy tales about the birth of human beings. The most famous legend is the myth of Adam and Eve. Adam and Eve used to live in the Garden of Eden, but later Eve stole Adam's forbidden fruit, so the Lord God who created them was very angry and drove them out of the Garden of Eden. Adam and Eve were forced to live in the world, and they continued to reproduce human beings and eventually to reproduce.

Adam and Eve were driven out of the Garden of Eden.

As we know, fairy tales are all imagined by the ancients, which contain very exaggerated and unrealistic plots. Take Adam and Eve as a man and a woman. Can they really reproduce the global population of 7.5 billion? If there is only one man and one woman on the earth, it will be difficult to continue the normal genes of human beings, let alone the birth of billions of healthy people. Why do you say that?

Adam and Eve TV series

Because if there is only one man and one woman on the earth, we will encounter a phenomenon that will cause great damage to the evolution of human genes. This phenomenon is inbreeding. Maybe Adam and Eve can give birth to healthy offspring, but the offspring of Adam and Eve can't reproduce because of blood relationship, because inbreeding will lead to deformity or even failure to reproduce. According to scientists' research, human beings must get married and have children after three generations, otherwise they will lose high-quality genes because of inbreeding.

For example, offspring born with mental disability, physical disability or obvious genetic diseases, and if these continue to reproduce, it won't be long before the offspring born to healthy Adam and Eve will be extinct, so it is impossible for two people to complete the arduous task of reproducing a population of 7.5 billion, and this is a speculation made without considering factors such as food, medical level, climate impact and wild animal attacks. If these factors are taken into account, the possibility of giving birth to another 7.5 billion people is even lower.

Natural marriage can lead to genetic defects.

Since only one man and one woman can't breed 7.5 billion people, how many people does it take to breed 7.5 billion people? Using computer simulation, scientists found that only gathering about 100 people can reduce the probability of human gene overlap to not affect high-quality genes, that is, only reaching 100 people can meet the diversity of genes in the process of human reproduction, thus leading to the lowest diseases, disabilities and mental defects. As long as the diversity of genes is guaranteed, human beings can continue to reproduce normally. Once they can reproduce normally, they can reproduce 70 times as long as there is enough time.

Map of human reproduction

According to the population growth index, it takes millions of years for human beings to grow from 65.438+0 billion to 200 million, thousands of years from 200 million to 65.438+0 billion, and more than 200 years from 65.438+0 billion to 7.5 billion. But if human beings grow back to 7.5 billion people, it will take millions of years, but according to the reproduction speed of primitive people, it will take millions of years. It may be possible to restore the population to 7.5 billion in a few hundred years. Because modern medical conditions are so high and the population is so small, human beings will certainly use various methods to encourage them to have more children. Once these 65,438+000 people have the awareness of having more children, the population may recover to 7.5 billion in 500 years.

In fact, this calculation result also gives us a revelation, that is, when human beings find the second earth in the future, when implementing interstellar migration, they must ensure that the number of immigrants reaches more than 100, so as to breed genetically high-quality human beings in the second home and realize the purpose of interstellar migration-survival and reproduction on other planets.