Human beings are the only intelligent life on earth, and they are advanced animals at the top of the food chain. There are as many as millions of animal species on the earth, and the number of different animal races is different. Human beings, as advanced animals, as the hegemon of the earth, are naturally the most numerous. According to the current statistical results, the number of humans on the earth The number reached 7.8 billion.
Once a friend left a message and raised such an interesting topic: If a disaster leaves the earth with only 1 man and 1 woman, how long will it take for the population to return to 7.8 billion? For this question, I believe there have been many discussions on the Internet. Different people have given different answers. Some people think that it will take at least tens of thousands of years to achieve. Others believe that it only takes a few thousand years to recover, while others believe that it only takes hundreds of years.
So which one is more reliable and accurate? In fact, there is no definite answer to this question, because the speed of population reproduction is affected by many influences. There are factors that come from nature, and factors that come from the speed of human development.
We all know that the ancestors of modern humans are actually African Homo sapiens 250,000 years ago. About 70,000 years ago, African Homo sapiens came out of Africa and began to spread to all parts of the world. After tens of thousands of years of evolution and development, the rich and colorful human world on Earth now has a population of 7.8 billion. So why did the 70,000-year-old African Homo sapiens go out of Africa and spread to the rest of the world?
Some people may say that it is because the ideals of Homo sapiens in Africa are great, and they want to spread the seeds of mankind to all parts of the world. In fact, this cognition is wrong, even modern people, I am afraid that not many people have such a noble sentiment. The African Homo sapiens is even less likely to have this kind of cognition. The fundamental reason that led Homo sapiens out of Africa 70,000 years ago was survival.
We must know that human ancestors can only use simple tools, and the requirements for the living environment are very high. Why millions of years ago, many kinds of humans were born in various parts of the earth, and only the African Homo sapiens survived? The core reason is that in ancient times, Africa was the place with the most abundant resources and the best environment on the earth.
The fine African grasslands and stable African environment have allowed Homo sapiens to continuously evolve and develop in hundreds of thousands of years. However, we must understand that the ecological environment of the earth will not be static and will often undergo some major changes. When Homo sapiens first started to rise 200,000 years ago, the population may have reached 20,000.
However, 70,000 years ago, a massive eruption of a super volcano caused a large number of global climate changes. This is the “Taba Catastrophe”. This ecological upheaval has a very large ecological impact on Africa. The original Homo sapiens tribe with more than tens of thousands of people only has about 1,000 people, but after the drastic changes, Africa is no longer suitable for the survival of Homo sapiens.
In order to survive, Homo sapiens had to step out of the African plains where they had lived for more than 100,000 years and began to search for new oasis environments around the world. In this way, the African Homo sapiens has gone out. After tens of thousands of years of development, the footsteps have spread all over the world, and the population has grown from more than 1,000 to the current 7.8 billion.
If a disaster leaves the earth with only 1 man and 1 woman, it is not a simple matter to restore to 7.8 billion people. If it is because of a devastating ecological disaster that only one man and one woman are left, then the two of them need to start from the primitive society to develop again. If all goes well, after tens of thousands of years of reproduction, the number of humans is expected to return to 7.8 billion.
If it were not for the drastic ecological changes that left human beings with only one man and one woman, then relying on abundant resources and a good ecological environment, two people would have to reproduce to 7.8 billion people. In fact, it would not take too long. It may only take thousands of years Time can do it. At the beginning, the reproduction rate of the population was naturally very slow.
However, as time goes by, the speed will get faster and faster. In fact, human civilization has only existed for about 5,000 years, while the world’s population may only be tens of millions before 5,000 years ago. Even before mankind entered the age of the Industrial Revolution, the world’s population was actually not large, perhaps less than 1 billion people.
According to a statistics of scientists, in 1800, the world’s population was about 1 billion years, and from 1800 to 2020, only 220 years have passed, but the population has nearly seven times. The reason why the population is multiplying so fast is mainly due to the benefits brought by technology. The advent of science and technology has made humans basically no longer hungry. At the same time, medical conditions and other conditions are constantly improving, and human life expectancy is also greatly increasing.
Of course, if mankind is left with only one man and one woman, relying on them to reproduce the prosperity of mankind, then we will have to consider another serious consequence, which is a series of evil consequences brought about by inbreeding. Gene is the core of the evolution of life, and the continuous mutation and evolution of genes is the foundation for the longevity of life.
Inbreeding cannot give genes better advantages and mutations, it can only make genes worse and worse, and make a species perform worse and worse. The evil consequences of inbreeding are numerous in human history. With the development of biology, human beings have deeply realized the disadvantages of inbreeding, so this kind of behavior is generally prohibited in modern society.
I believe many friends know that human genes are actually not perfect, and there are many defects in our gene pool. These defects are actually the result of inbreeding from the ancient ancestors of human beings. It is not long before humans really began to pay attention to inbreeding and prohibit it, and it may only take hundreds of years at most.
We must know that in the feudal era of our country, marriage of close relatives was also a relatively common phenomenon. Only after human beings have entered the era of science and technology, and with scientific guidance, can people truly realize the harm of inbreeding. However, the various hazards caused by the long years of evolution have already existed in the human gene pool.
We want to eliminate these defective genes continuously. There are two methods. One method is to slowly optimize through the continuous mutation of offspring genes. Another method is to use more and more advanced genetic technology. In the future, humans may use gene editing technology to continuously optimize human genes, so that various defective genes can be eliminated from our gene pool. At that time, humans will become Higher life.
The current global population has reached 7.8 billion, and this number is still growing rapidly. It is estimated that by 2100, the world’s population will reach 11 billion. Scientists believe that the earth’s population capacity is about 10 billion. If this number is exceeded, the earth’s ecology will face significant pressure. Overpopulation is also a major survival crisis for mankind.
And to get rid of the survival crisis brought about by overpopulation, the only way out is to achieve space colonization. Only we have become an interstellar civilization and can colonize more living planets in the universe. It is only 80 years from 2100 to the present that can solve the various crises brought about by the ever-increasing population. If 80 years later, human beings are still unable to migrate to other planets, then we will face a major crisis brought about by overpopulation.