The average size of human bodies has changed significantly over the last millions of years, due to climate change.
This is the conclusion of a new study of scientists led by the British University of Cambridge and the German University of Tübingen, published by the journal Nature Communications.
Researchers collected data on the size of the brains and bodies of more than 300 human fossils, including modern homo sapiens. The team has combined this data with climate reconstruction over the past millions of years and calculated the climate in which people whose fossils have survived lived, the CNN television server wrote.Read also Archaeologists in Egypt have discovered the rare ruins of an ancient vessel from Herakleion
Researchers have found that climate – especially temperature – has been a major factor influencing body size changes over the past millions of years. A colder and harsher climate is associated with larger bodies, while a warmer climate is associated with smaller ones, researchers have discovered. “Larger bodies can protect individuals from low temperatures – the bigger you are, the smaller your surface area compared to your volume, so you save heat more effectively,” explains Andrea Manica, a professor of evolutionary ecology at Cambridge University.
Researchers have also studied the impact of the environment on brain size, but the relationship to climate is less clear here.
Homo sapiens appeared about 300,000 years ago in Africa. However, the genera of man, which also includes Neanderthal man and other extinct related species, such as homo habilis (skilled man) or homo erectus (upright man), existed much earlier. Experts say that compared to previous species such as homo habilis, homo sapiens is 50 percent heavier and its brain is three times larger – but the causes of these changes are still debated.Read also SAS: In Slovakia, they confirmed the first case of human infection with a lung worm
A team of experts found that while climate also plays a role in brain size, there are so many variations that it cannot be explained by changes in the environment.
“Changes in brain size were not related to temperatures at all, so body and brain sizes developed under different pressures,” says Manica. “Climate explains changes in brain size much less than changes in body size. This means that other factors, such as cognitive challenges associated with increasingly complex social life, a more diverse diet and more sophisticated technologies, have probably had a major impact on changes in brain size, ”the scientist added.
At the same time, he said, it is unlikely that current climate change will have a dramatic effect on the body size of today’s people. “The changes we have described have taken place over thousands, or rather tens of thousands, of years. So a few years of climate change won’t do much to our bodies or brains, ”says the researcher.Read also CNN: Scientists have identified 14 living descendants of the famous Leonardo da Vinci
Nevertheless, climate change may already have an impact on the shrinking of some animals. In the last four decades, North American migratory birds have been shrinking, and their wingspan has been increasing. According to a study from 2019, these changes are probably a reaction to warming. In the analysis of 70,716 dead birds, representing 52 species, the researchers found a statistically significant reduction in body size in 49 species. And the temperature in the summer nests of these opera, which was north of Chicago, rose by about one degree Celsius at the time of the study.
Another study from 2011, published in the journal Nature Climate Change, concluded that cold-blooded animals such as toads, turtles or snakes also change with increasing temperature – their bodies shrink.
Source: Pravda.sk – Veda a technika by vat.pravda.sk.
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