Table of contents:

What happened to the human body over the past 100 years
What happened to the human body over the past 100 years
Anonim

Modern people are not like those who lived 100 years ago. We are much taller, we live longer, we have more and more often the median artery of the hand and less often wisdom teeth grow. And we also have new bones. Are we still evolving? Or are we just adapting to new conditions, like all living organisms?

(Some) people got taller

A study published by the Institute for the Study of Labor (IZA) in Bonn, Germany, found that young people in the UK have grown by about 10 centimeters since the early 20th century. Until a century ago, the average height of 20-year-old recruits averaged 168 cm, and now it is 178 cm.This change is most likely associated with improved nutrition, health care and hygiene conditions, researchers from the University of Essex, UK, said.

In many other developed countries, people have also become taller, reaching the current average height of 1.85 meters - for example, in the Netherlands. This is more than in other countries. Interestingly, the Americans were the tallest people in the world during World War II, their height was 1.77 meters, but by the end of the twentieth century, they lagged behind. Now, according to the study, the growth of Americans has not changed.

And even in some countries where average growth is growing, it has not been uniform. For example, people from the former East Germany are still catching up to the height of the former West Germans after years of communist rule. And in some non-Western countries plagued by war, disease and other serious problems, average growth has declined at one point or another. For example, between the late 19th century and 1970, South Africa experienced a decline in average growth. This was because the decline was likely due to worsening socio-economic conditions before and during apartheid.

Image

That being said, growth appears to improve people's quality of life and their chances of survival. For example, in the United States, taller people make more money on average because they are considered “smarter and more powerful,” according to one study.

Early puberty

Children in many countries these days mature earlier. According to a 2003 study published in the journal Endocrine Reviews, menarche age in the United States declined by about 0.3 years per decade from the mid-1800s (when girls first menstruated at an average age of 17) to the 1960s.

Scientists suggest better nutrition, health and economic conditions. They often play a role in reducing the age of menarche. Today, the average age for menarche in girls in the United States is between 12.8 and 12.9 years. However, the onset of puberty is defined as the time when a girl's breasts begin to develop. In North America, it is 9.7 years for white girls, 8.8 years for African American, 9.3 years for Hispanics, and 9.7 years for Asian descent.

Image

Earlier puberty can have long-term health consequences, Biro said. For example, studies have shown that girls who mature earlier are more likely to develop high blood pressure and type 2 diabetes later in life.

There are also social consequences of earlier puberty. In some cultures, when a girl is biologically mature, she is also considered mature enough to be married. This often means that she will no longer be able to continue her education or make a career.

Thus, the later a girl begins her first period, the better for her overall educational and life prospects.In fact, a Harvard study published in 2008 in the Journal of Political Economy found that in rural Bangladesh, where 70% of marriages take place within two years after menarche, every year of marriage delay equals 0.22 additional school year. At the same time, literacy is growing by 5, 6%, respectively.

New artery

In the early stages of pregnancy, a median artery forms in all human embryos in the area of ​​the future forearm. Its task is to help blood pass through the center of growing arms and to nourish them. As a rule, by the eighth week of embryonic development, it disappears, and its place is taken by the radial and ulnar arteries.

But this does not always happen. Back in the middle of the 18th century, anatomists noticed that in some people, an additional vessel functions throughout their lives. But there were no more than 20% of such people. A recent study has shown that over the past 25 years, an additional vessel has become more common in humans.

The mechanism of regression of the median artery in the embryo is regulated by special genes. This means that there have been changes in the work of DNA sections.

Disappearing teeth

The absence of wisdom teeth is noted in about 20% of Europeans. More and more often, specialists do not observe even hints of them in patients. And if they are, then they are in the wrong position or do not cut through to the end. This fits into the general evolutionary trend and is most likely associated with a change in diet, the researchers note.

Image

In general, the process of formation of Homo sapiens is the history of teeth reduction. Our ancestors had large molars in the back of the massive jaw, which made it possible to chew solid food for a long time.

About 2, 6 million years ago, the diet became more varied: meat was added to plant foods. After another two million years, people mastered fire and learned how to heat food. The chewing time has decreased significantly, the size of the jaw and teeth has decreased, and the posterior molars - those very wisdom teeth - are no longer needed. Scientists from Harvard University (USA) confirmed this thesis in one of the studies.

New bone

Scientists began to find in humans a bone that was considered lost a century ago - fabella. At first glance, bone is useless, but for some unknown reason, it began to be found in human skeletons three times more often.

Fabella, a small bone in the human skeleton that was once thought to be lost in the course of evolution, has become common again after a fairly short period of time. The fabella of the knee joint, according to the anatomical structure, is the sesamoid bone, which is located in the inner surface of the gastrocnemius muscle and joins the posterior condyle of the thigh.

Image

Scientists believe that over time, the patella needed additional protection: the average height and weight of people increased, the load increased, and this bone became necessary.

The modern person, on average, eats better than those who lived 100-150 years ago. People are now taller and heavier - this triggered the development of longer legs and larger calf muscles, which, in turn, increased the pressure on the knee.

Longevity and its consequences

According to the World Health Organization, people are now living longer than ever. The average life expectancy worldwide has grown from ~ 30 years in the 20th century to ~ 70 years in 2012. Globally, WHO predicts that life expectancy for women born in 2030 in countries such as the United States will rise to 85 years. Increased life expectancy may be associated with significant medical advances, improved sanitation, and access to clean water, Bogin said.

While all of these factors have also significantly reduced mortality from infectious diseases, deaths from degenerative diseases such as Alzheimer's, heart disease and cancer are on the rise. In other words, people live longer and die from other diseases than before.

As is often the case with the biological benefits that humans sometimes receive, old age also comes with trade-offs.

The more of us live longer, the more and more of us are faced with death, which will be long and unworthy, scientists say. You have to pay for everything.

For example, autoimmune diseases such as multiple sclerosis and type 1 diabetes have also become more common.

Popular by topic