Evolution Continues? How people have changed since Darwin

2024 Author: Malcolm Clapton | [email protected]. Last modified: 2023-12-17 03:44

We became weaker and colder, but we grew up and grew new bone and artery.

When people talk about evolutionary changes, they usually mean long-term processes that take thousands or even millions of years. Therefore, it may seem that by the 19th century, when the theory of evolution was established in a more or less modern form, man was already fully formed and there was nothing for him to adapt to.

However, data collected over the past two centuries show that the human body continues to adapt. This process can also be traced in such a short time interval by the standards of biology, as 150-200 years and less.

How people have changed over the past 150 years

The creation of culture is believed to have accelerated evolution. Perhaps they even spur each other on. The thing is that the complication of social life and scientific progress led to drastic and global changes in the existence of people. Humanity has gradually adapted to the environment, and this is reflected in our body.

Average height and weight increased

The most obvious change is that we are getting bigger. Over the past 100 years, women and men have become taller by an average of 11 centimeters. The same goes for children. A century ago, schoolchildren of 8–12 years old were 10–15 centimeters lower than modern ones.

The main reason is social progress. We began to eat better, get sick less. Even 100 years ago, many children were forced to help their parents with hard work. Very scarce nutrients were spent not on strengthening the body, but on labor. This negatively affected bone formation and slowed down growth.

The better the quality of life of people, the higher they themselves are due to the disappearance or reduction of additional negative factors. For example, stress. When children are worried, their energy is spent fighting stress, not growing. A more varied diet also had an impact. Thus, increasing the intake of vitamin D strengthens bones and promotes their development.

Also, the average body mass index - the ratio between height and weight of a person - has increased. If in 1864 for nineteen-year-old young people this indicator was 21.9, then in 1991 it reached 23.4. For people over 45 it increased from 23 to 26.88. The change is explained by an improvement in nutrition and a decrease in physical activity.

As a result, over the past 300 years, the area of human skin (literally the size of our body) has grown by 50%.

Muscles become weaker

The increase in size did not make us stronger. This is again the "fault" of progress. Both adults and children began to engage in physical labor much less and to move in general. The consequences can be seen in the study of adolescents 15-17 years old. Over 34 years (1970–2004), the grip strength of the hand decreased by 27% in boys and by 33% in girls.

Body temperature dropped

American scientists analyzed more than 670 thousand readings over 157 years of measurements and came to the conclusion that during this time our temperature dropped by almost half a degree: from 37 ° C to our usual 36.6 ° C.

This could be influenced by the fact that earlier a significant part of the population suffered from tuberculosis, syphilis and mumps. For example, tuberculosis was very common and therefore remained one of the leading causes of death. On average, about 1% of the population died from it, and during outbreaks, this number reached one third. Infections could be the reason for fever: this is how the body reacted to diseases.

There is another possible reason. Body temperature largely depends on a person's metabolic rate. The higher the life expectancy and the larger the body size, the slower the metabolic processes in the body. As people began to live longer, and they themselves became larger, the metabolism slowed down, and with it the temperature dropped.

New bone and artery appeared

More serious changes have taken place in the human body. So, we have become 3.5 times more likely to meet fabella - a small bone that is located on the back of the knee.

Scientists explain the appearance of a new bone by an increase in the height and weight of a person's body, which increased the load on the knees and the nearest tendons. The fabella is supposed to be needed to protect them.

Scientists also noticed that the median artery began to occur in humans three times more often compared to the end of the 19th century. It is located on the inside of the forearm and runs along the center of the forearm. Typically, the median artery is used for blood flow to the arms only in the fetus and regresses by the eighth week of pregnancy. The place of the median is occupied by the radial and ulnar arteries, which remain with a person for life. But today, the median artery persists in about 35% of people. Certain parts of DNA are responsible for this, that is, microevolution is taking place before our eyes.

How will we change further

Some scientists suggest that in the future, women will have an increase in the reproductive period due to delayed menopause and early sexual development. Perhaps this is the body's reaction to the growing life expectancy and later childbirth among modern mothers.

It can also be assumed that if the increase in height and weight, along with muscle weakening, continues, people may have difficulty walking upright. Indeed, in order to move a larger body, on the contrary, you need more strength, and there is nowhere to take them.

But it is still very difficult for us to predict which path human evolution will take. Obviously, it will depend on the development of technology. Genetic engineering, neurointerfaces, bioprosthetics, exoskeletons, artificial intelligence - it is not known how all this will affect us.

It should also not be ruled out that the world as a whole may change, for example, as a result of a global catastrophe or because of a revolutionary discovery. So, breakthroughs in genetics, biology, chemistry and prosthetics promise a person potential immortality and transformation into biorobots. But on the other hand, global warming can deprive us of our usual rich diet, and nuclear war - and all the benefits of civilization. The coronavirus pandemic has already become a formidable warning of an unfavorable scenario.