"Swedish scientists have investigated the potential risks for the species Homo sapiens, which can lead our species to an evolutionary dead end, that is, to gradual extinction. The authors wonder whether the rapid technological leap will become an evolutionary trap for our species. In your opinion, how justified are such fears? Why do scientists have such concerns, even though the number of our species is constantly growing?
— In theory, any biological species can go extinct, and ours is no exception in this sense — who knows what cataclysms may await our planet after, for example, a large asteroid falling on it? But if we leave such scenarios out of brackets, then there are no prerequisites for the extinction of the Homo sapiens species. First of all, because our species is very good at adapting, we have mastered almost all ecosystems and feel quite comfortable everywhere. Our species is represented by very different populations, and the specific morphological and physiological characteristics of local populations were formed as adaptations that made it possible to master specific ecological conditions: highlands, deserts, and so on.
- © kadmy
For example, the indigenous inhabitants of the highlands of Tibet, the Andes, and Ethiopia have developed features that allow them not to suffer from oxygen starvation. The changes affected their respiratory and circulatory systems, and were recorded at the genetic level. The indigenous inhabitants of the Andes, who live at high altitudes relatively recently by evolutionary standards (less than 11,<> years), have adapted by increasing the concentration of hemoglobin in the blood: their red blood cells carry more oxygen, and their red blood cells are larger.
These people have an increased residual lung capacity and associated growth of the alveolar region of the lungs, but the rate of respiration is about the same as that of the plains. Tibetans, on the other hand, have different adaptations. They do not have elevated hemoglobin concentrations, but they inhale large volumes of air with each breath and breathe faster than the inhabitants of the Andes or the plains. Tibetans have an increased lung capacity throughout their lives and a steady increase in cerebral blood flow.
Europeans are different from Africans, and Africans living in dry desert climates are physiologically different from those who inhabit the humid tropics. Residents of the Far North also have their differences. Moreover, the differences are quite comprehensive, the intensity of sweating differs, there are peculiarities of the functioning of the cardiovascular system, skin, lungs, etc. That is, even at the physical level, a person has a huge potential for adaptation. And modern technology makes it possible to treat diseases that were previously considered fatal, which further increases humanity's chances of survival. In addition, the development of gene technologies suggests that in the foreseeable future we will be able to correct some congenital genetic defects, which will make our species healthier.
- Neanderthals (illustration)
- © Denis-Art
So you don't agree with the popular view that the development of medicine has slowed down natural selection in the human population?
— First of all, you need to remember that selection takes different forms. Along with driving natural selection, which forms new traits, stabilizing selection is also important, keeping some traits unchanged. Of course, medicine influences the pressure of natural selection in a certain way. For example, where modern medicine is available to all, childbirth takes place in medical facilities and almost never ends in the death of the woman, as is the case in countries with low levels of modern obstetric care. But it should not be forgotten that modern medicine is still inaccessible or inaccessible to the population of a number of regions of the planet. For example, in a number of African countries, medicine is still used only by residents of large cities, and in rural areas, the population more often resorts to traditional methods of healing, which have come down to our time since ancient times. So the impact of modern medical technology on a global scale should not be overestimated.
- © Guido Mieth
"Now in all developed countries the birth rate is decreasing, respectively, not all people leave offspring, the percentage of childless people is growing. What is the reason for this decline? Why does this depopulation occur at all, how much is it a social mechanism, and how much is it a biological mechanism? After all, before in history, the birth rate was low in conditions of scarcity of resources, among ancient hunters and gatherers, and now, on the contrary, in conditions of their abundance – why?
"You need to understand that even in wealthy and developed countries, resources are not evenly distributed – there are rich, there are middle class and poor people, there are those who are below the poverty line. And the birth rate among these social strata is also unevenly distributed. If we take a closer look, we will notice that most of the children are born to rich people who can provide their offspring with a good education and starting opportunities. And often, the richer a country is, the more pronounced the social inequalities in terms of access to resources, including healthcare, education, quality environments and leisure opportunities. The birth rate is in the same row. From the point of view of evolution, successful reproduction and prospects for offspring are the leading motivation of humans. It is an innate unconscious motive formed in the process of evolution.
"There is a hypothesis according to which both language and intelligence in general developed when our distant ancestors found themselves in extreme conditions – they were taken out of the forests to the open area, to the savannah. Only those individuals that developed mental capabilities unique to animals were able to survive there. Do you agree with this theory, and what other versions of the origin of humans are there?
"I wouldn't call the African savannah an extreme environment for monkeys, I work a lot in Africa and I know this firsthand. The savannah is a very rich ecosystem, and modern apes are also developing it, especially on the border with the forest. The savannah today is home to many species of monkeys – not only baboons, but also many different species of monkeys, hussars, and chimpanzees. Chimpanzees living in the savannah demonstrate wonders of adaptability and use various objects in everyday life, such as rocks and sticks. These skills are passed down from generation to generation within the same population, and entire "cultures" are formed. Groups of chimpanzees living in the savannah have better cooperation and are more cohesive. So yes, cognitive development seems to be better stimulated in the savannah than in the forest.
How did our distant ancestors, the apes, transform into the first humans?
"We now know that the primate species that became our predecessors lived in the savannah, where there is a pronounced seasonality, in the dry season there is a shortage of plant food. This prompted primates to eat more animal food, and it became their adaptive strategy. Moreover, in the savannah, it is easier to identify the victims, the animals gather near water sources. Since our ancestors had a pronounced intelligence, they were not only good at navigating in space, but could also plan and coordinate their actions, and hunt collectively.
- © Suzanne Cordeiro
Modern chimpanzees, by the way, are also good hunters, mainly males are engaged in catching prey. Among them, the most experienced male trapper and a group of beaters usually stand out, who coordinate the game in his direction. This is, in fact, driven hunting. In the Gombe Stream National Park in Tanzania, chimpanzees mainly hunt colobus monkeys. In other places, young baboons, monkeys, wild boars, and antelopes. After catching the game, the prey is divided, the main male must necessarily share with the others, otherwise they will no longer help him. So, even on the example of modern chimpanzees, we can observe under the influence of what factors the intelligence of our ancestors could have developed, what factors underlay the formation of the rules of cooperation and morality.
The need to increase the proportion of animal food in the diet was an important condition for the development of cognitive abilities and in-group cohesion.
— Can the evolution of chimpanzees move towards the development of cognitive qualities? Can these changes, if any, be recorded?
— This is a very difficult question. The first person to study chimpanzees in their natural habitat for a long time was Jane Goodall, who began research in the 60s. Since then, a lot of data has been accumulated, research is being carried out in a number of African countries, studying not only common chimpanzees and bonobos, but also gorillas and other anthropoids. Observations suggest how and why some new skills may emerge in monkey populations. Initially, such skills may arise by accident - for example, an individual will discover that it is convenient to prick large insects with a pointed stick, such a strategy is described in the bonobo population. And then the other members of the group begin to imitate her.
- Jane Goodall, Primate Researcher
- © JEAN-MARC BOUJU
New communication signals may emerge to indicate new sources of danger. Many populations of gorillas live in wetlands, and when they cross a swamp, they can probe their way with a stick, and so do humans in a similar situation. Overall, it is now clear that great apes have much greater cognitive potential than was thought in the middle of the last century.
"In some ways, people's behavior is similar to the habits of our 'relatives', chimpanzees. For example, patrilocality, when a young female leaves her native group and moves to a new one, is characteristic of both apes and human traditional cultures.There are also conclusions of scientists that a similar way of life existed in Neanderthals. Does it mean that such behavioral attitudes have been passed down in primates for millions of years?
"Of course, you can't compare chimpanzees and Neanderthals, they are separated by millions of years of evolution. Modern chimpanzees are not our ancestors, but representatives of a separate evolutionary branch from us. In the Paleolithic, humans were hunter-gatherers who organized themselves into small communities within which even smaller cells formed.
This is how the modern wandering hunters and gatherers of the Hadza people, the indigenous people of Tanzania, live. — RT). A population consists of fluid, non-permanent associations. The Hadza are generally monogamous. But most often it is serial monogamy, they can change spouses several times in their lives. Only about 5% of men, usually those referred to as the "camp master" – that is, the most authoritative man in the group – are allowed to practice polygamy. But even then, such polygamy is usually short-lived, because most often the former wives leave such a man - they do not want to tolerate rivals. In general, judging by a number of evolutionary adaptations of the body, man is oriented towards monogamy.
At the same time, the composition and size of the group still depend on the season. During the rainy season, the Hadza gather in a larger community and hide together from the jiggings under the rock canopies. But still, married couples are never separated and move from group to group together. In addition, very often a woman with small children is helped by their mothers. Grandmothers look after their grandchildren while the parents forage for food.
- A member of the Hadza tribe
- © chuvipro
— Is it correct to talk about the biological predetermination of some social attitudes, for example, monogamy? Or are we becoming more flexible and diverse because of social evolution?
— Of course, there are certain biological prerequisites. For example, it is known that pronounced sexual dimorphism, when the male is much larger than the females, is associated with polygamy in primates. In the process of evolution, humans experienced a decrease in sexual dimorphism in a whole set of characteristics: body size, canine size, etc. This suggests that the ancestors of modern humans began to lead a monogamous lifestyle long ago.
And also that both parents had to contribute to the care of the children. Such transformations in behavior had to take place in parallel with the transition to bipedalism. The restructuring affected the entire body and led to significant changes in the structure of the pelvis. It has been made wider and lower in order to facilitate the process of childbirth.
However, the increase in brain size in the process of human evolution has become one of the main challenges to human survival. The head of the fetus had to pass through the birth canal, and it was limited by the size of the female pelvis. Because of this, childbirth in a person turned into a great risk, the process became painful. The problem was solved thanks to earlier, taking into account the stage of development of the fetus, childbirth. A human child is born less developed than the young apes and completely helpless for a long time. Adaptation in the form of paternal care and the care of the mother's closest relatives made it possible to compensate as much as possible for the risks for the survival of newborns in our ancestors.
- © Morsa Images
I would like to note that in traditional societies, pregnant women must observe strict prescriptions and taboos related to diet. These taboos are often aimed at restricting the growth of fetal body size. Indeed, Hadza newborns are born very small, often not reaching 2 kg in weight, but after birth, children grow very quickly and gain weight quickly. In traditional societies of itinerant hunter-gatherers, fathers spend a lot of time and energy helping their wives and caring for their children. And, of course, they try to provide food for the family.
Does the biological evolution of Homo sapiens continue today? And in what direction is it moving?
"We can't look too far, but we can outline trends that can be expected in the foreseeable future. As I said earlier, humanity is becoming healthier, and life expectancy is increasing. Thanks to medicine, more children survive, and each person is a carrier of a unique genotype, possibly very valuable to the population. Therefore, genetic diversity will increase and the potential of the human population to respond flexibly to environmental changes will increase.