Scientists can predict evolutionary changes in the human body driven by the changing living environment. But what will we look like if we move to live on Mars or return to the oceans? How would the human body adapt to surviving nuclear winter?
According to Dr. Andrej Suchomlinov, a researcher at Vilnius University Faculty of Medicine, the human body, hair color, height, and weight will change, and internal and external organs will also adapt to the changing human living environment.
Fewer blue-eyed, blond-haired people
Dr. Suchomlinov says that the changes in the human body will be visible in 50-100 years already. They will be influenced by recessive and dominant genes in the human body and intensive globalization processes. For example, dominant genes for darker skin, brown eyes, and darker curly hair will lead to the predominance of these morphological characteristics.
“Blue color of eyes will be rarer in the future because the gene that determines the blue color of the iris is not dominant. During evolution, both the human jaw size and the number of teeth will decrease, which should also change the proportions of the face. Wisdom teeth are already unnecessary and will be the first to disappear. Canines resemble incisors because their function has changed during evolution,” he says.
As for other changes in the body, Dr. Suchomlinov says the human digestive tract would likely shorten in tens of thousands of years due to increasingly processed foods and improved industry. However, if the currently increasingly popular vegan, vegetarian, or raw food lifestyle were to take hold, the digestive tract would have to become longer, as it takes more time to absorb plant materials.
Genetic engineering, which is continuously progressing, will also play an essential role in the future. However, many ethical questions in this area still need to be answered: “Vaccines provide an opportunity to prevent diseases, but if it is possible to choose the color of a child’s eyes and hair, it will be hardly possible to predict the future.”
Human height and weight are highly variable
Some morphological characteristics stop changing and become stable. One such change is height.
“People began to grow taller in the first half of the 20th century, and in the Western world, this growth stopped several decades ago. It seems that we have reached a certain height limit. However, one of the indicators that has constantly been increasing in recent years is body mass index (BMI),” Dr. Suchomlinov says.
“Theoretically, there is no BMI limit. In some countries where obesity is common, the average BMI is over 30, while the norm is up to 25. We believe that this increase may continue, not only due to epigenetic and other factors but also because there has never been an opportunity to get a lot of calories in a simple way. Obesity among past generations was extremely rare; it appeared only when the layers of high society separated”, he adds.
Martians – a new human species?
Although certain traits have disappeared in human development, such as abundant body hair, specific physiological reactions have remained. For example, goosebumps are a reaction common to other animals.
Erect hairs make an animal appear larger to defend itself in case of danger. However, in humans, it is an unnecessary rudimentary reaction. According to Dr. Suchomlinov, 50 years ago, it was believed that the appendix was also a rudiment. But now we know that it is an important immune organ. Just like the coccyx – the remainder of the tail and a part of the spine that is important for the functions of the pelvis.
Due to future changes, it is believed that the fingers of people who spend a lot of time using smartphones will deform and become longer: "Such changes take much more time, and most of them do not have a scientific basis, at least not yet." Thus, the atrophy of the earlobes or the membranes between the fingers is pure speculation.
"Everything will depend on where we live. Will we move to the ocean or Mars? Will we live after a nuclear war, or will there be extremely high temperatures due to global warming?" he says.
Mars is being considered quite intensively as an alternative for human habitation. Due to the scientific research and other space missions carried out on Mars, it is already known that within a 6-9 months long trip to Mars, the human body would change: the heart may weaken, the probability of blood clots may increase, the density of bones may become thinner, and muscle tissue may decrease.
In addition, a human grows in space – during a year in the state of weightlessness on the space station, the height increases by about 5 cm.
"Ultimately, if some people stayed on Earth and some moved to Mars, eventually, there would be so many differences that they would no longer be able to interbreed. This means there would be two different human species," Dr. Suchomlinov says.
Science fiction and possible reality
Science fiction suggests that people would have to live in a spaceship for tens or even hundreds of thousands of years to move outside the solar system.
“When thinking about scientific issues, there is a question of radiation. A dose of radiation during such a flight would be huge. This would require effective DNA repair mechanisms and excellent physiological indicators,” said Dr. Suchomlinov.
Another future scenario is a return to the ocean. Like in mammals that once returned to water from land, the bones of human limbs and body proportions should change significantly: “To get an idea of how we would look, we should look at aquatic mammals – dolphins and whales. The bones of their limbs are just like ours, only with different proportions. Our body should also be sleeker, more like a sphere.”
Another possible scenario is life on Earth after a nuclear war.
“I read that even in the event of a nuclear war, when all the available weapons of the world are used, a small number of people would still survive. But, of course, there would be a very long nuclear winter, and the climate would change dramatically – there would be cold temperatures and famine.
The human body would adapt to the lack of resources and contracts. Due to the high radiation, a large number of mutations are expected, which, if they would offer an advantage, would be passed onto future generations,” said Dr. Suchomlinov.
The article was first published in Vilnius University's popular science magazine "Spectrum."
Your email address will not be published. Required fields are marked