10 shameful questions about a person: science popularizer Alexander Sokolov answers

In this series articles, well-known experts answer questions that are usually awkward to ask: it seems that everyone already knows about it, and the questioner will look stupid.

Today we are talking with science popularizer Alexander Sokolov about why not all monkeys became people, where people with light skin came from, and whether humanity will become extinct.

1. Is man the pinnacle of evolution?

This is a common phrase, flattering for the person himself. But it is not very clear what “the pinnacle of evolution” is. By what parameters do we determine this? If we take the most intelligent species of animal, then it is man. But who said that evolution must have a peak and that it must be associated with intelligence?

For example, ants invented sociality 100 million years earlier than humans, forming a complex society. And cheetahs run faster. And intestinal parasites get along just fine without a brain. Any existing organism feels great in the form in which it is.

Yes, a person is unique in many ways, there are a lot of people. But this does not mean that we are better than others.

“The pinnacle of evolution” is not a scientific concept, but rather a philosophical one. Many people, when talking about evolution, depict a kind of ladder. Lamarck was one of the first to draw such a ladder of creatures, and his representation about evolution was somewhat idealistic. It seemed to him that all living things were moving towards one goal and that goal was man.

But in the modern view, all living things simply develop, change and react in different ways to changes in the environment. This is what evolution is all about. This is a natural process, it has no goal.

2. Why do some people have white skin if the first people were dark-skinned and from Africa?

According to all data, man really came out of Africa. AND ancient people, who came out of Africa were most likely dark-skinned - we can determine this using paleogenetics, if we can read the DNA data.

We know that after leaving Africa, people - Neanderthals, Cro-Magnons - were dark-skinned for a long time. 8–10 thousand years ago, dark-skinned people lived in Western Europe, but some of them were already blue-eyed. And later, some populations in Europe and Asia brightened.

Skin color depends on climatic factors, primarily on the intensity of ultraviolet radiation.

Therefore, the closer to the equator, the darker the skin. Dark pigment is more suitable in sunny regions because it absorbs ultraviolet radiation.

It has long been assumed that as people moved farther from the equator, their skin began to lighten because there was less ultraviolet radiation. This made it possible to receive at least a small dose of UV. Because a person needs a certain amount of ultraviolet radiation for the synthesis of vitamin D3, without it he develops rickets, osteoporosis.

But when paleogenetic data appeared, it turned out that for tens of thousands of years after people migrated to Europe, they remained dark-skinned. And they brightened only about 7-9 thousand years ago, around the same time when agriculture appeared.

There were many people, but little game, and it was necessary to move from hunting and gathering to cultivating cereals, so food became more monotonous and less rich in vitamin D. That’s when the skin began to lighten, because the role of solar radiation for the synthesis of this vitamin increased.

Mutations associated with fair skin began to spread across the continent, and in 1,000 years people became lighter, as evidenced by studies of hundreds genomes ancient people.

3. If we are descendants of apes, why have we lost almost all our hair?

In fact, a person has not lost his hair, because we still have hair. At the same time, we have even thicker hair on our heads than chimpanzees, but on our bodies it is much less common. Men grow beards, but chimpanzees do not have such lush facial hair. And gorillas, for example, do not have such thick pubic hair as humans.

That is, we are not talking about the disappearance of hair, but about a change in the nature of the hairline and how it develops throughout life.

Moreover, the monkeys themselves have less hair follicles per square centimeter of skin than any cat. And in anthropoids monkeys less than, for example, a monkey. Thus, hair thinning has accompanied the entire evolution of primates.

Why this happened involves many hypotheses, none of which can be fully confirmed because we don't have much data. After all, hair is rarely preserved in fossil form, and from the remains of a Neanderthal, for example, we cannot say what kind of hair he had. We can only guess.

Now the most substantiated and popular hypothesis associates the disappearance of hair with a change in heat transfer.

When our ancestors were sitting somewhere in the forests, they felt good with their wool. But the climate became more arid, and forests began to disappear. Therefore, some of the great apes switched to life in the savannah, where the scorching sun creates a problem. You have to survive somehow, and the person stood on two legs, because this reduced the heating area of ​​the body. Sweating has also increased, and liquid evaporates better from smooth skin rather than from hair: the latter interfere with cooling. That's why our ancestors began to go bald. Thick hair was left on the head to protect from direct sunlight.

4. Why do some peoples have thicker hair, for example in the Caucasus and the Balkans, while others have less hair, for example in Asia?

Even within a small group of people, some are more hairy, some less. People are quite changeable, especially considering that now this trait has ceased to play an adaptive role.

But it survived sexual selection. In some populations, for some, perhaps random, reason, women liked smoother men, while in others they liked hairier men. Therefore, today, different hair thicknesses are likely the result of sexual selection in different human populations.

5. Is it possible to judge a person’s mental abilities by the shape and size of the skull?

No, you can’t, although all sorts of racial theories have been built on this for a long time. It is now clear that the development of bone relief on the skull and the structure of the skull in general within the species Homo sapiens does not correlate in any way with mental abilities.

6. Why don't modern apes turn into humans?

Evolution continuous, but this is a very slow process that we cannot observe during our lives. Changes can be seen over hundreds or even thousands of generations. And if you are waiting for the monkey to turn into a good fellow, it will take many, many years.

I have already said that each species is unique and not every monkey has to become a human. A certain species of monkeys, once upon a time, for various reasons, embarked on the path of humanization. And other ancient monkeys in the process of evolution became chimpanzees, gorillas, gibbons, capuchins, and so on. These are simply different paths of evolution.

One might as well ask why all modern monkeys do not turn into gibbons.

If you take monkeys that are similar to our ancestors and put them in conditions similar to the conditions in which our ancestors lived, perhaps in a few million years something human-like will emerge. But still not completely human, because it is impossible to create completely identical conditions.

7. Is man an omnivore?

Man is in fact an omnivore, like many monkeys. For example, our closest genetic relatives are chimpanzees. They eat plants, but can also eat bird eggs, hunt small mammals, and are sometimes even seen cannibalizing.

But it is precisely in human evolution that the amount meat increased in the diet. At the same time, now in some communities the diet is more meat-based, while in others it is vegetarian. Which just confirms the fact that we are omnivores and can adapt to different diets.

8. Is it true that humans are the only creatures that enjoy sex?

No it is not true. For example, bonobo pygmy chimpanzees are very loving, they often engage in a variety of sex, even same-sex.

Some other animals, such as dolphins, also describe various sexual games. Some animals masturbate, which suggests they enjoy it.

9. Does a person evolve further into someone else? Will it look any different? Will a superman appear?

Scientists don't really like to make such predictions because they can't be tested. But science prefers to talk about what can be verified.

We can say that in a few million years a person will have three finger, a huge brain and a decrease in the number of ribs - this is how paleontologist Bystrov jokingly depicted a person in 1957. But how do we check this? It turns out that these are unscientific ideas.

To understand how evolution will go, you need to understand what factors will influence it in the future, and in what conditions a person will live.

And our environment is changing so quickly that it is difficult to say what will happen in 50 years. When, for example, it is assumed that the use of smartphones will change a person’s fingers, it is ridiculous to discuss this seriously. Interfaces are developing so quickly that people simply do not have time to evolve to them.

I assume that in the future, people will simply change themselves more actively and interfere with their body with the help of some kind of bionic prostheses, genetic modifications, and so on.

Man is likely to interfere with his own genome, ranging from color changes eyes, ending with the correction of some genetic errors or diseases.

10. Will humanity go extinct?

Yes, there is a chance that we will become extinct, because many species have disappeared. Or maybe we won’t go extinct and will somehow evolve.

So far, despite all the diseases and wars, the planet's population is only growing. It seems like we'd rather destroy the planet than we'll go extinct as a species.