Are humans still evolving today?

Are humans still evolving today?

Author: Mao Ning Science Popularization

Singer Tanya Chua has a song called "Darwin". It is really touching to hear "learn to be serious, learn to be loyal, and only the fittest can survive" in a love song, coupled with the singer's exquisite voice.

However, in reality, we seem to have built a fence between ourselves and natural selection: relying on abundant food and advanced medical conditions, our life span has been greatly extended, and hunger and many deadly diseases have disappeared in many parts of the world. Optimism, or perhaps another kind of pessimism, has even raised another question: Is our life good enough? Are we still "evolving"? Since the power that could eliminate bad genes in the past is being disintegrated in the name of humanitarianism, will we be biologically frozen? Even, does this freezing bring new dangers?

It is quite difficult to answer this question. First of all, it is a misunderstanding about the theory of evolution: the theory of evolution emphasizes the adaptation of organisms to the environment, but we often misunderstand that the evolution of organisms has a direction from low to high. If we add the "value judgment" of direction, the factors that prevent organisms from being faster, stronger, or smarter seem to have become stumbling blocks to evolution. But if we use the index of adaptation to measure, then who cares whether you are like the song says: "Evolving into a better person"? After all, better is not as good as more adaptable.

Another question is whether we are really eliminating the power of natural selection (no one cares about sexual selection, which we probably verify every day). For example, if diseases that would have caused rapid death in the past were genetic, can they now be cured and passed on to future generations? Have individuals who were not able to adapt to the environment in the past been given the opportunity to reproduce because of a less harsh environment? If we continue to deduce this way, a less politically correct question will soon come up. But wait, let's calm down and discuss this issue carefully. The unit we discuss evolution is not the individual, but the population. Indeed, let's temporarily play the role of the cruel nature, the heaven and earth are not benevolent, and treat all things as straw dogs. Then we don't care who will survive, the weak or the strong. Instead, the survival of a population is the issue that should be considered on a large scale. And the civilization developed by human beings can be seen as a powerful "adaptation" that has helped our population adapt to the complex and changing natural environment from the Arctic to the South Pacific Islands. It has achieved great success in the past tens of thousands of years. Soon, this adaptability may send us to extraterrestrial planets. From this perspective, if more of us didn't die of disease before puberty, it wouldn't be such a serious problem. Oh, look where we are on this.

The third difficulty is that it is difficult for us to analyze the impact of evolution on human populations. Of course, the study of whether natural selection is still affecting humans has never stopped. Last May, a study by British, German and Finnish scientists was published in the Proceedings of the National Academy of Sciences, entitled "Natural and sexual selection in a monogamous historical human population". The lucky scholars found population data from several villages in Finland from 1760 to 1849. These data contain the birth, marriage and death data of 5,924 people from the archives of the local church. Because of the detailed records and because Finland's strict Christian beliefs oppose divorce (all second marriages occur after the widowhood), this data is very good at preserving how many offspring men and women of different wealth have. Scientists found that half of the population died before the age of 15, and even if they survived adolescence, 20% of them failed to get married or had no children. Here, the god of death really harvests lives regardless of wealth. Wealth differences cannot make a person have more or fewer offspring. On the contrary, attractive men have more offspring because it is easy for them to remarry, and their remarried wives are often younger. This harsh picture appeared less than two hundred years ago. Even in Europe during the Industrial Revolution, the power of natural selection and sexual selection still used their giant hands to deprive lives and give those attractive people more opportunities to reproduce. Perhaps this power still plays a role in life. Tanya Chua sings in her song: "Reading the theory of evolution, I agree with Darwin. Those without strength may be eliminated." In this example, this strength is mainly healthy genes, not social wealth.

To be optimistic, our ancestors were very successful in evolution, which gave rise to the human world. To be pessimistic, most of the creatures in this world have become extinct in the past. Humans have done quite well in the past 100,000 years. The only way to understand the future is to let it happen.

This article is produced by Science Popularization China-Starry Sky Project (Creation and Cultivation). Please indicate the source when reprinting.