In the late 1800s, British anthropologist and anatomist, Arthur Thomson, asserted that people of ancestral origin living in cold, arid climates generally had thinner and longer noses, while those of ancestral origin living in cold, arid climates generally had thinner and longer noses, while those of People from warm, humid climates have shorter, thicker noses.
He hypothesized that climate had a profound effect on the shape of the human nose , more than any other evolutionary factor, because the nose’s important job was to warm and humidify the air inhaled through the nostrils. nose. This helps explain why people in colder climates have narrower nostrils and vice versa.
For years, scientists have been testing Thomson’s Nose Rule on simulated skulls, but until now no one had done this study on a living person.
Researchers at the University of Pennsylvania (USA) were the first to do so. The results, published in March 2017 in the peer-reviewed journal PLOS Genetics, confirm Thomson was right. The researchers concluded that nose size and shape evolved, at least in part, to adapt to local climatic conditions.
Arslan Zaidi, a postdoctoral fellow in biology and lead author of the study, said: “We often ask questions like: Why do we look different? Why do men and women look different? Why are people living in different populations different? We focused on the nose because a lot of research on the human body shows that it can evolve to adapt to the climate.” .
The East Asian nose is low to adapt to the climate.
The researchers scrutinized the parameters of the nose. They examined the width of the nostrils, the distance between the nostrils, the height of the nose, the length of the bridge of the nose, the protrusion of the nose, the area outside the nose and the nostrils using a 3-D technique. The researchers also focused on studying four different ancestral populations: South Asian, East Asian, West African and Northern European.
Two questions the researchers asked: Do some nose shape features vary with populations rather than genetic variation? (Transmission variation is a random evolutionary process that results in differences between populations over a long period of time, in a completely random manner.) If so, can these changes be explained by climate?
Natural selection likely played an important role in human nose evolution.
“In other words, we still predict that if two populations are isolated over a long period of time, their noses will randomly look different because of genetic variation,” says Zaidi. subtract this to show that differences between human populations depend on many other factors.In seven measurements that describe nose shape, we found two related to nose width that differences between populations are not simply due to genetic variation. This means that differences in nose width between human populations are not purely coincidental.”
The researchers found a positive correlation between nostril width and temperature and humidity, suggesting that natural selection likely played an important role in human nasal evolution. Natural selection is the process by which organisms that are well adapted to the environment usually survive and pass on traits to the next generation, while organisms that are unable to adapt often die.
Humans are always on the move. Today, it is not uncommon for a person from a cold climate to move to the equator. They will probably “challenge” the narrow nostrils of their ancestors.
Zaidi added: “Evolution has taken a long time. If the nose shape evolved before to adapt to the local climate, that time must have been up to 10,000 years. So, great-grandchildren. mine will probably still have wide noses, because I’m Pakistani, even if they live in colder climates, as long as they’re married to another South Asian.”
“Human differences are not identical with the concept of race. There are more similarities between people from different populations than differences, both genetic and phenotype. Traits. such as skin pigmentation and nose width are more different because they are typical of environmental habits and evolve faster than other human traits. “, Zaidi added.
In addition to climate, there are also a number of other factors that affect the shape of the nose.
The researchers also note that other factors may also be involved, such as gender differences. Men are usually taller than women, so their noses are usually larger as well. Other characteristics also play a role here as people may prefer a partner with a smaller or larger nose. However, according to scientists, the concept of beauty may have to do with how well the nose is adapted to the local climate.
As for the nose, Zaidi says that evolution is an extremely random process, making it difficult to predict what will happen to the human nose in response to global warming.
“Human evolution, at this moment, is very different from evolution in the past. Our way of life is not like what our ancestors used to do, we move everywhere,” said Zaidi. That makes predicting the future evolutionary trajectory of the nose to adapt to climate change extremely complex.”