Why do modern men live not as long as women, but still longer than before? And why have sons grown taller than their fathers for several generations? What other changes are taking place with human bodies right now, and what does social stratification and other social factors have to do with it? The Science Channel talked about men and their evolution with the anthropologist Elena Godina.
The reason for the conversation was the publication of Australian scientists who announced that men die earlier than women due to the natural set of chromosomes. According to their findings, the Y chromosome is not able to fully protect an organism with a heterogametic sex (XY) from harmful mutations in the X chromosome. Women are more fortunate: they have two X chromosomes, so defective DNA can be compensated for by the presence of normal DNA.
– Elena Zinovievna, can you comment on the study of the Australians? Is the life span of men really related to the characteristics of the Y chromosome, and not to the way of life?
– Yes, I read about this study. Biological anthropologists have been talking about this for a long time. The two X chromosomes act as a defense mechanism for women. Two copies of genes give stability. Men have only one X chromosome, the other a Y chromosome, and this does not provide stabilization and such protection. This affects in many ways – not only in relation to life expectancy, but also when it comes to the impact of unfavorable environmental factors on growth processes. These factors are more likely to influence the growth and development of boys.
When we talk about genetic factors, we mean the biological aspect of sexual dimorphism.
But we have many examples of populations where women do not live longer than men. For example, in Bangladesh and some other countries
And then we talk about gender characteristics and the influence of sociocultural factors. Anthropologists always pay attention to these two points.
– How has the life span of a man changed in the course of evolution? And how did modern Russian men live longer?
This applies to both men and women. For example, a lady of Balzac’s age is a 30–40-year-old woman … And if you look deeper into the Middle Ages and even further, the average life expectancy there was generally short: about 20–30 years. Because there were terrible epidemics and diseases. So our life, of course, has lengthened – in connection with the improvement of living conditions, the victory over many diseases.
Now we are faced with an unknown disease, and you see what an epidemic! .. It is now progressing in many countries and affects the lives of a huge number of people. But, undoubtedly, humanity will cope with this.
And so we, in general, have conquered many diseases. Life expectancy has increased largely due to the characteristics of the lifestyle. Researchers of the phenomenon of Japanese centenarians associate this primarily with dietary habits. We also conducted such a study in Abkhazia. It was a joint Soviet-American project to study the phenomenon of longevity. We then went to Abkhazia and studied the features of the physical development and lifestyle of these people, and it turned out that there is such a specificity as high physical activity until the very late years. Also influenced by nutrition – the Mediterranean diet, which everyone now knows about, and then it was a kind of discovery. Another important point: social relevance. There is such respect for elders, they are really significant in society. After all, as I said, in addition to biology, sociocultural factors are also important.
– Is evolution going on now? How are modern men changing?
– Of course, some changes are taking place. This is an interesting and big topic, on which a huge amount of work has been written. Certainly, if we take the last 100-200 years, we will see well-documented changes – first of all, they concern men. This is due to the fact that regular measurements were made in connection with the recruitment into the army: they measured body length, weight and other parameters. And we certainly know that there has been a significant increase in body size. The pace was different in different countries.
For example, in Holland, the body length of men has increased by 15 cm – can you imagine what giants they are! And somewhere – only 3-5 cm
But the direction of change is the same: growth has increased. In recent years, we have not seen such an increase, the process has stabilized.
But some other transformations are taking place. In the 1990s and 2000s, we anthropologists observed certain changes in the physique: narrower, dolichomorphic bodies. Both boys and girls were different in this. But the girls are still bigger. According to many polls, boys tend to be more masculine. There are such works on assessing your bodily image – body image. And if girls always strive to be slimmer – and, even if they are already thin, want to succeed even more in this, – then boys do not want to be thin, but want to be more muscular, they are aimed at developing muscle mass. This tendency is obvious among young people, which, in general, reflects the real specificity of the morphology of the body of the modern population.
– What is the reason for the fact that men have “grown up” over a hundred years?
– There are many factors. But it is believed that there is a contribution of genetic factors. With the development of civilization, the circle of marriage relations expanded. Marital assortativity was at work, when taller women chose taller men. But the improvement of socio-economic conditions also affected: the development of health care, a decrease in morbidity, better living conditions, and nutrition. There is a common phrase: growth as a process is a mirror of the development of society.
There is another interesting thought that no one writes about. When a society is strongly divided into rich and poor, the resulting component is always lower than in other populations, where all strata of society live in more or less uniform conditions, as happens, for example, in the Scandinavian countries. And in Holland it was no coincidence that such a growth spurt occurred in men and women too.
Social differences are sometimes dramatic. These topics are always very interesting to tell and illustrate. When I give lectures on these topics to students, it always takes my breath away even for me.
For example, here are two curves of changes in body length in North and South Korea: the common starting point is 60 years ago, and at the end of the line they diverge by 7 cm *. That is, the changes are colossal and depend on economic parameters and social conditions.
* Difference in growth in favor of South Korea. Approx. ed.
Now more and more literature is being collected about the effect of psychoemotional stress on people. Earlier this topic was also raised – about the influence of the environment. For example, if you are surrounded by fat people, then you yourself are more likely to become fat. And now there are data on a lot of physical parameters. Our German colleagues are investigating this and call it the “community effect”. What kind of environment are you in and how do you feel in such an environment? These factors contribute to the differentiation of growth.
– Does this mean that men in the future will become even taller?
– You know, there is now a certain stabilization of longitudinal growth. Recent surveys have shown that very little change is taking place. This is the same as with life expectancy. We can improve the living conditions as much as we want, but there is a certain limit to these possibilities. And in terms of life expectancy and growth. Of course, if total organ replacement and 3D printing of the heart, kidneys and other things do not begin …
– Do anthropologists compare Russian men with Western men or men from the Third World? Are there such studies and are there any interesting observations?
– We, of course, always compare the development trends that we observe in Russia, with European countries, with the data that is in the literature. In general, the trends are the same for everyone. Third world countries have their own characteristics, as I said: the life expectancy of women in some of them is shorter than that of men. We are undoubtedly developing in the tendencies of European countries. But usually we are talking about Moscow, and Moscow is not all of Russia. To understand the current trends in changes in the physical parameters of the population, it is necessary to conduct large-scale studies in many regions of Russia.