Why natural selection is not so important today and what happened to our instincts - biologists say
Miscellaneous / / June 27, 2023
But the ability to learn is necessary, as before.
Moscow Institute of Psychoanalysis spent "Big Biological Lecture Hall". It included a discussion on natural selection and the role of genetics in the study of evolution. Biologists Alexander Markov and Alexey Kulikov talked about how the evolution of homo sapiens differs from the development of other biological species. Recording a discussion posted on the Institute's YouTube channel. Lifehacker made a summary of the conversation.
Alexander Markov
Doctor of Biological Sciences, Professor, Head of the Department of Biological Evolution at the Biological Faculty of Moscow State University, popularizer of science.
Alexey Kulikov
Doctor of Biological Sciences, Deputy Director of the Institute of Developmental Biology. N. TO. Koltsov RAS.
More than a century has passed since Darwin's theory of evolution was formulated. Science has advanced a lot over the years. But the theory of evolution was not refuted; on the contrary, it received many confirmations. Including thanks to the development of genetics.
How important is culture in human evolution
A person, unlike all other biological species of our planet, has an important advantage. Humans develop, like other species, in the course of normal genetic evolution. But at the same time there is a cultural development. Therefore, scientists say that the process of human development is determined by genetic and cultural co-evolution.
Earth civilization has been actively developing largely due to the language. We have speech, so we can communicate much more effectively with our own kind than representatives of other species. And also to master all the knowledge that society has accumulated. The development of the species Homo sapiens occurs as follows:
- We are creating a cultural environment. We communicate, form rules of conduct, develop production, and learn. This is how cultural evolution takes place.
- Culture influences biological evolution. Now scientists are increasingly talking about the fact that in humans it is she who sets the direction of natural selection.
- The results of biological evolution influence the development of culture. This may be delayed. But, for example, the development of the brain as a result of natural selection will certainly have an impact on cultural processes.
Here is a textbook example of the influence of culture on biological processes. It is known that mammals do not drink milk as adults. It only goes to babies. Adult animals eat a completely different food, and they do not need milk. Therefore, enzymes that break down lactose - that is, milk sugar - are only found in babies of all mammals. In grown individuals, they simply cease to be produced.
In ancient times, man had the same thing. People who have gone beyond childhood could not drink milk without unpleasant health consequences. But it was completely unimportant, because then our adult ancestors simply had nowhere to take it from.
Then, as a result of cultural evolution, people began to engage in animal husbandry. They domesticated animals that give a lot of milk. And the moment came when people began to receive surpluses of this product. It was more than what the kids needed. Therefore, adults also began to try to drink it.
At first, their stomachs ached and their digestion suffered. But then, as a result of a series of mutations, the situation changed. Some lost the mechanism that stopped the production of an enzyme that breaks down lactose. They could drink milk without ill effects. As a result, these people received a selective advantage - because their diet became richer. This means that the ability to survive with a lack of another food also increased. Therefore, such people ate better, lived longer and left more offspring.
Interestingly, similar mutations have arisen in human populations in Africa, the Middle East, and Europe. In these three regions, different mutations were fixed in people, which led to the same result. It can be simplified to say that they all broke the same genetic tool, but in different places.
Here is such a simple example of gene-cultural co-evolution. Culture has created such a situation that a selection began for an ability that did not exist. The population responded to selection, and this ability spread.
Alexander Markov
Modern humanity is the descendants of those who have retained these mutations. Therefore, today most adults can safely use dairy.
What happened to instincts as a result of evolution
This question also shows that human evolution has taken a slightly different path than that of animals.
Modern science refers to the complex patterns of behavior that animals have from birth as instincts. The beast does not need to be taught, for example, how to respond to danger. In response to a certain stimulus, he will automatically act as his instinct tells him to.
Interestingly, humans do not have such innate patterns of behavior. So, from the point of view of science, we have no instincts. Everything that a person needs, he must learn.
Each of us has innate traits: features of temperament, abilities, inclinations. Scientists have established that all of them are realized only when interacting with the social and cultural environment. Human behavior can also be determined by genetic characteristics. But it is formed only when communicating with other people. Eat skills and skills that one person can learn faster than another. But everything that is needed for life and development, he must learn from scratch.
Here is the most striking example. Humans certainly have a powerful innate predisposition to mastering a language. This is an innate supertalent of young children. But the language itself is still not innate. That is, it does not go as an instinct - all the same, the child must learn from his parents. So people have no instincts, and there are no disputes about this in serious science either.
Alexander Markov
Does the process of natural biological selection affect people today
As a result of evolution, people almost left the process of natural selection. In any case, today its significance is much less than even 150 years ago.
The importance of reducing harmful mutations has greatly diminished
Today we have almost no purifying selection. Previously, he rejected mutations that made the body weak and vulnerable. Now people can live and develop, even if some organs do not work perfectly.
Here is an example. With the advent antibiotics the load on the immune system was drastically reduced. Therefore, people who have immunity-lowering mutations may not be afraid of germs today. Previously, they often died from infections and did not have time to leave offspring. Now they calmly cope with a sore throat or bacterial pneumonia, and then they live long and give birth to children. It is important that those, too, can manifest these harmful mutations. This means that purifying natural selection does not work in this case.
The same story with gene changes that regulate brain function. In Iceland and the United States, scientists conducted a study of the level of education and intellect adult residents. It turns out that in our days the number of people who receive one, and even more so several higher educations, has greatly decreased. In addition, scientists have recorded a decrease in the average level of IQ.
This happens because today people do not need to make enormous intellectual efforts in order to survive. The world is quite prosperous and friendly without it.
Yes, indeed, the conditions are so good that it is not at all necessary to be seven spans in the forehead and study seriously in order to secure a good life for yourself.
Alexey Kulikov
That is, in this case, we see the consequences of reducing the role of natural selection.
The absence of rigid biological selection does not weaken humanity
Many people who become aware of these trends become worried. They worry about whether our descendants will become completely weak and unadapted to life. You can calm down: while scientists do not see processes that are dangerous for our species.
Yes, on the one hand, medicine today helps to preserve and pass on to descendants mutationsthat impair certain bodily functions. But humanity has been around for a very long time. Let's see what abilities it has already lost.
According to some reports, primitive people began to use fire about two million years ago. They invented and created stone tools, learned to cook and fry food. These cultural advances have led to the fact that people no longer needed powerful jaws and large teeth. After all, the need to gnaw at hard roots has disappeared.
Today we have small jaws and small fangs and incisors. They will not help to cope with primitive raw food. But we don't suffer from it at all. After all, we have the tools to prepare the food that suits us.
People began to use the skins as clothing and warm themselves by the fire. Then they started building houses. And lost in the course of evolution wool - it turned out that heat can be preserved without it.
Is it scary that we are left without wool? Maybe not much. Well, the invention of antibiotics does not really need - I'm simplifying, of course - the immune system. We have had cultural dependencies for a very long time. Yes, we can't survive naked in the wild. But we do not need this, because we have clothes, equipment, fire, and so on.
Alexander Markov
Advanced medicine allows us to live longer and more active
Today, there are many people among us who a couple of centuries ago could leave the earth early. We have reached a level of development where there is no need to make a choice between morality and expediency. That is, there is no need to decide whether to leave the weak child to the mother or get rid of him. Modern civilization considers it important to cure a sick baby. And then make him a full member of society.
Society can also take care of older generation. Today, thanks to advances in medicine, many people over 60 can play sports. For example, kayaking. Previously, only young members of our species were capable of this. The elderly, of course, still have diseases today. But modern drugs allow them to feel good and be active. So advanced medicine is our evolutionary advantage, not a weakness.
The next important step that science must overcome is to learn how to defeat complex hereditary diseases. And deal with the process of reproduction stem cells. This should help people live longer and retain intelligence well into old age. Stem cells are a complex topic, but today it is one of the most promising in biology.
If humanity learns to treat serious diseases, edit the genome so that they do not remain, and track this, then the transformation of a person into a non-reproductive stunted creature will not happen. And keeping yourself in shape is the task of each person, the task of education. Therefore, I hope that people do not turn into smart octopuses.
Alexey Kulikov
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