Humanity has been living on Earth for about 300 million years, constantly changing throughout the entire period of its existence. People living on Earth today, representatives of the species Homo sapiens, appeared relatively recently - between 200 and 50 thousand years ago. They, unlike other humanoid primates, walked out of the African jungle into the savannah on two legs, learned to talk, produce tools and organize their life.
About why in the process of evolution man became erect, despite the fact that it is unnatural in the conditions of our planet, how the human body will change in the conditions of life on Mars, what transformations await him in the future and why other planets are no longer colonized by humans, in an interview RIA Novosti correspondent Irina Alshaeva on the eve of the centenary of the Department of Anthropology, Faculty of Biology, Moscow State University. Lomonosov was told by Associate Professor of the Department of Anthropology, Candidate of Biological Sciences Stanislav Drobyshevsky. - What scientific facts confirm the correctness of the provisions of the work "On the Origin of Species" by the founder of the theory of evolution, Charles Darwin? Does the modern scientific community agree with his conclusions, or are there opponents of the theses put forward by Darwin?
- There are no scientists who argue with Darwin's theory. However, Darwin's theory and modern evolutionary theory are not the same thing. Darwin voiced his assumptions about the evolutionary development of species in the middle of the 19th century; by the middle of the 20th century, his theory had turned into a synthetic theory. 70 years have passed since the middle of the twentieth century, the Darwinian theory is developing, as scientists make new discoveries.
The basic tenet of Darwin's theory is the concept of natural selection. Then he added the theory of sexual selection to it. Selection in Darwin's understanding was a differentiated transfer of the characteristics of individuals to the next generation. He did not say anything about genes, as there was no such thing yet.
In the 30s of the twentieth century, population genetics appeared, then molecular genetics. By the 50s and 60s of the last century, scientists had figured out how genes work. Then it became clear what exactly is passed from generation to generation - the variants of the structure of DNA are transmitted.
Subsequently, this concept became more complicated, but its essence remained the same - all living things have hereditary information, it changes and is transmitted to the next generation with a greater or lesser probability, depending on the adequacy of the environment, and sometimes by accident. As a result, after a long period of time, the descendants are so fundamentally different from the ancestors that we call them other species, genera and families.
Not a single biologist argues today with any of the steps in this chain. The controversy concerns super parts. Scientists argue, for example, about what is more important in evolution - chance or pattern. But these disputes are not about the concept in general, but about specific situations.
In the 60s of the last century, the geneticist Theodosius Dobrzhansky said that "nothing in biology makes sense outside the theory of evolution." Indeed, without its binding force, all biological facts turn into a set of facts, and nothing more. Only the theory of evolution explains the logic and reasons for the ongoing changes in the development of species.
Against this background, what is the predictive value of the theory of evolution? How can knowledge of its processes be applied by scientists in the future?
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- The predictive value of the theory of evolution is that if we know how biological processes took place in the past and what led to this, we can predict what will happen in the future. A good example is the use of this knowledge in the process of growing new varieties of agricultural plants. But mainly this knowledge is needed to work in the field of genetic engineering, which is the future of humanity. Genetic engineering allows us to "shift" the necessary genes and obtain the properties of an individual that we need, and not in the future, but much faster.
Scientists have learned to modify crops and food at the genetic level. The next step is genetic modification of the person himself. Now all over the world such experiments are banned, but Chinese scientists have announced the birth of a child whose genome has been modified in such a way that he cannot get AIDS.
This is definitely a scientific breakthrough. But the problem with such manipulations with the human genome is that public organizations, especially religious ones, are resisting these experiments. But despite these protests, genetic engineering will become a part of our lives in the near future. After all, humanity sets itself the goal of surviving, and with uncontrolled reproduction and depletion of natural resources, this is impossible.
Anthropologist Stanislav Drobyshevsky demonstrates a cast of a Homo naledi skull in comparison with a human skull. Archival photo. RIA Novosti / Sergei Pyatakov.
We are already in a state close to extinction, the Earth's useful resources are going down, the peaks of coal and oil production have already been passed. The problem of the world's population can be solved in different ways, including through genetic engineering. It is obvious that it will be used.
Otherwise, humanity will again find itself in the Middle Ages. Over the next 300 years, mankind will burn all coal and oil and degrade. In the Middle Ages mode, it will be able to exist indefinitely, but the life expectancy will be reduced to 30 years and its level will drop sharply. But, for example, few people will have problems with the cardiovascular system, since people simply will not be able to survive until the age of diseases associated with it.
What types of living things are transitional from simple organisms to humans? How much has its evolutionary chain been studied?
- These transitional forms are all paleontology. All fossil creatures are either dead-end branches - if they became extinct, or they gave birth to descendants who live now. Any fossil creature is an intermediate link from our ancestors to us. At the moment, all transitional forms from the first chordates to humans have been found.
Of course, there are periods of time in which there are no or few paleontological finds, because not all geological layers have survived, and not all animals, either, but the main stages have been found.
Human evolution has been studied better than the evolution of other creatures. There is a subtle point - scientists understand in general from which groups of Mesozoic mammals primates arose, but from which species it is not clear. There are known groups of ancestors of modern man - these are primitive placentals.
For example, from pikaya (a primitive chordate animal, its fossils were found in the Middle Cambrian sediments aged 530 million years in the Burgess shale (Canada) - ed.) To us there is a direct sequence. There were a million branches along the way, including the sequence to the desman or the dipper bird. It turns out that the dipper, for example, is closer to the lizard, and the man to the desman, but both the man and the dipper have a lot of ancestors from this lancelet.
At what stage of evolution is the development of man as a biological species today? What organs and systems of the human body have disappeared during evolution, what appear?
- Man is just at the next stage of evolution, it will end with his disappearance. Now we are a kind of species stage, as, for example, the Australopithecines were four million years ago. Then they were the crown of the hominid creation, but now they are an intermediate stage. We are also such a stage between the Heidelberg man, who lived in Europe 700-345 thousand years ago, and the people of the future.
We, in comparison with our ancestors, have lost a lot in our anatomical structure, but the question is - compared with what ancestors? With fish, man has lost his gills, although our trapezius muscle is the branchial muscle. Compared to the first primates, humans have lost their tail, but we still have a tailbone - each person has four vertebrae that end in the spine. There are also tail muscles, theoretically you can even wiggle them.
The skull of a Heidelberg man, who lived in Europe 700-345 thousand years ago, is kept at the Department of Anthropology, Faculty of Biology, Moscow State University. Lomonosov.
Our main acquisition is a large brain, which we now have more than any of our ancestors, with the exception of Neanderthals and Cro-Magnons. Over the past seven million years, the size of the human brain has grown 4.5 times - from 300 to 13500 cubic centimeters. But over the past 25 thousand years, it has decreased by 5%. The brain changes at a rate of 1 kilogram in seven million years, that is, 140 grams in a million years. During the existence of sapiens, the brain dries up - 3 grams per thousand years, which is 20 times faster than the previous increase.
We have acquired large body sizes - there was no one larger than us from primates in the past. Over the past seven million years, the size of the human body has increased approximately one and a half to two times - from 1 to 1.7 meters. We also acquired a grasping hand, but lost the grasping foot like in primates. The person acquired a complex of upright walking with accompanying problems with the spine and abdominal cavity - since the body suddenly changed from a horizontal position to a vertical one, muscles and bones were unfavorably rearranged.
Then what is the reason for such an illogical human need for upright walking?
- Man stood upright for three million years. Between 15 and 10 million years ago, our ancestors switched to vertical tree climbing. They began to move along the branches in an upright position, because before that there were big cats that spoiled the life of their ancestors.
Monkeys, fleeing from them, began to jump faster, and their tail lengthened. And the great apes have increased in size. They became heavier, and they could not jump - this is why they lost their tail. With a large body weight, it was inconvenient to move along the branches on all fours. It is convenient - in this case, rest your lower limbs on the branches, and cling to them with your upper limbs. Thus, the body of our ancestors was reformatted to an upright position while still in the trees.
Then, between ten and seven million years ago, when the forests in Africa turned into savannas, the great apes almost disappeared, and those who remained went to the savannah. But here, again, we are not talking about a specific monkey - we are talking about a chain of species that went out into open territories for three million years.
By the way, a person walks on two legs for about four million years, walking itself and adapting to it are different things. We still walk uncertainly on two legs. We fall, but in nature - in other species - this is not. But vertical climbing has remade our body so that getting back to horizontal would be a bigger problem than staying on two legs. This was a plus for our ancestors living in Africa. Their body heating area was reduced, a psychological advantage over predators appeared, and they were able to start engaging in tool activities - making tools.
If the ancestors of man began to make tools, it means that they have a mental activity that involves the development of speech. How did the brain evolve, for example, its speech center?
- Our speech center has heritability, these genes have been isolated today, but half of them are unknown to science. The speech apparatus is connected not only with the brain, it also includes the larynx, the spine, the lower jaw, and the temporal bone. In addition, it is not enough to speak - it is necessary to hear speech, therefore the development of the speech center in humans entailed the development of hearing organs. These changes are observed in the fossil remains. The speech apparatus begins to form in habilis - a skilled person (Homo habilis - ed.). There is a big problem with the study of the brain of our ancestors, because the brain, of course, is not preserved. However, studies of this organ are being conducted on casts from the inner surface of the skull. They show the relief in the place where the speech center is located in a modern person. Australopithecus did not have it, Habilis does,sapiens smoothes out, because their frontal lobe increases - that is, they began not only to speak, but also to think. The conclusion is unambiguous - both the brain and the ability to speak of our ancestors have evolved unambiguously.
How will a person change in the conditions of colonization, for example, Mars?
- It depends on what initial conditions for their habitation people can create there. If by some miracle they manage to reproduce exactly the terrestrial ones on Mars, then the person will not change much. However, mutations are inevitable. In conditions of complete isolation from the Earth, people who will create a colony on Mars will be able to transform into a new species - the Martians. But, most likely, it will not be possible to reproduce completely terrestrial living conditions on another planet. Then the changes in the human body will depend on the conditions of the planet - radiation, gravity, magnetic fields.
But in order for earthlings to completely turn into Martians, genetic changes must accumulate over generations, and for this people must live there for a very long time. We have a generation length of 25 years, and accordingly, thousands of years of population life on Mars are needed. It is known that races are formed in four thousand years - that is, that is how much is needed for ancestors to differ from descendants. At the species level, this will take 50,000 to 200,000 years. Thus, it is necessary that these people live on Mars for 50 thousand years without contact with earthlings.
It is difficult to imagine that for thousands of years people on another planet lived in complete isolation from the Earth and successfully reproduced themselves. As for the initial number of Mars colonizers, a few dozen will be enough.
There are tribes on Earth that live in small numbers. These are the Andaman aborigines who live in the Andaman Islands in the Indian Ocean in the number of 200 people, and the Sentinelians living on the North Sentinel island. These tribes avoid contact with strangers, but this does not lead to their degeneration.
Does incest hurt them too?
- Incest does not lead to undesirable consequences in offspring, if the parents do not have harmful recessive mutations. The harm of incest is that the recessive gene goes homozygote. But if this recessive gene is not present or it is not harmful, then related individuals can interbreed.
What role does genetic engineering play in colonizing other planets?
- The key. Today, people have knowledge of population genetics and mutations. With the help of genetic engineering technologies, people will be able to literally correct their shortcomings - by “screwing up” the necessary genes based on the needs of their environment, they will be able to correct their traits in the direction they need. Now genetic engineering is developing much faster than the technology that allows you to fly to Mars. We can edit the genome, but we haven't got to Mars yet. Therefore, by the time a spaceship capable of delivering people to Mars is made, genetic engineering will go very far.
If a person gets to other worlds in order to survive in them, he will have to change himself. For example, on Mars, in our modern bodily shell, we will not be able to exist, since other external and internal organs are needed there, so people will create themselves according to the necessary needs. Most likely, other planets are no longer colonized by humans.
How does the scientific and technical process affect human evolution?
- As a result of the fact that the ancient man began to make tools, he formed the so-called labor complex of the brush. Actually, this is where the biological changes of a person associated with the development of progress ended. But the brush has changed because the survival of the species directly depended on the manufacture and use of tools.
Late scientific and technological progress hardly influenced our anatomy. Rather, he influenced physiology. For example, the large amount of plant foods that humans have been consuming since Neanderthal times have led to mutations that help our bodies break down starch better. But these are minor advances.
The fact is that the scientific and technological process is very fast, and biological progress takes hundreds of millions of years. For the scientific and technological process to influence our biology, it is necessary that its achievements do not leave our lives for hundreds of years in a row. But it changes quickly.
We can say that today we - if we talk about the inhabitants of big cities - live in conditions unnatural to us. Every resident of a metropolis, going out into the street, experiences stress, since a person by his nature must live surrounded by a family of five to twenty people and know everyone throughout his life. If he sees a stranger, then at the level of instincts, two options are possible - to marry him or kill him. Wild times are over, and we have not adapted to new ones.
How, presumably, a person can look in the near - by biological standards - future?
- The immediate prospect of changes in our appearance is understandable. If we analyze what happened to our ancestors, it becomes clear that our third molars - wisdom teeth, as well as some other teeth - will disappear - children are already being born without a second incisor and without canines.
In modern people, wisdom teeth are usually small, they grow between the second molars and the ascending branch of the lower jaw, which causes a lot of trouble for their owners. Often times, the upper and lower third molars are not in contact with each other. They do not self-clean from this, therefore they quickly deteriorate.
But for many ancient people, third molars were the largest and most important teeth, and behind them, to the ascending branch, a vast space gaped. Therefore, our ancestors not only did not experience problems because of these teeth, but also depended on them. With the transition to high-calorie meat food and the advent of tools, the size of the teeth has become less relevant. These teeth began to decrease in size, and two million years ago, the process of their disappearance began.
So, among the early Homo, the remains of an individual with a congenital absence of the right lower third molar were found, and on the jaw from Chenjiao, which is half a million years old, there are no longer two wisdom teeth. Now this option is found in almost most people. However, for some, third molars are still the largest teeth. Now man as a species is in a state of active evolutionary transition. A couple of hundred thousand years will pass, and the second molars will be called wisdom teeth.
People's heads become rounder and smaller. However, this trend can stop and go back, as it is happening now in England. Asthenization has been going on for the last 150 years - people are getting slimmer and taller. Asthenic body type is natural for our species. It is connected with the fact that we have learned to live like in the tropics - with the help of heating and warm things, against the background of which our body does not need to gain weight to protect itself from the cold.
From the internal organs, the appendix is the first candidate for disappearance. It will either disappear completely in the future, or it will turn into a gland. As for the legs, metamorphoses in the foot are inevitable - it is unambiguously transformed, since it is poorly adapted for upright walking. It is difficult to say exactly how it will look, because in the past there were no bipedal upright creatures, therefore, we have no precedents for comparison. Most likely, the muscles of the foot will be replaced with a ligamentous apparatus, and the foot itself will look like an elephant. The foot will become smaller, acquire a fat pad, and its arches will disappear, since they are not needed. For the same reason, the fibula and sense of smell will disappear.
The portrait of our descendants is not very attractive
- From the point of view of Australopithecus, you and I are not very attractive either. Attractiveness is a subjective concept. From the point of view of an amphibian, for example, we are generally something unimaginable. Imagine how, in her understanding, hair looks like. It's one thing when the skin is smooth, moist, shiny and with venomous glands, and another thing when something bristly sticks out of it.
Our state for us in our perception of the only attractive, while other options for the appearance - our ancestors or descendants - seem to us to be something unthinkable.