The climate has changed the size of the human body and brain in the past one million years

　　”Nature Communications” magazine recently disclosed that in the past one million years, climate has changed the size of our human bodies, and to some extent, it has even changed the size of our brains.
　　An interdisciplinary research team composed of the University of Cambridge in the UK and the University of Tübingen in Germany collected more than 300 anthropogenic fossils from all over the world and extracted data. Through comparison, they found that in the past one million years, climate (especially temperature) has been the main factor causing changes in human body size. In addition, the size of the brain has also changed, but evolution did not coincide with the size of the body.
　　Colder climates tend to give rise to larger body sizes, while humans living in warmer weather tend to be smaller. Professor Andre Mannika from the Department of Zoology at the University of Cambridge pointed out that a larger body size is considered a buffer against cold weather. The larger the body size, the greater the body’s mass relative to its surface area, and the more effective it is to retain body heat.
　　A decisive feature of human evolution is the continuous increase in the size of the body and brain. Compared with earlier races, our body is 50% heavier than them, and our brain is three times larger. This time, the researchers also noticed the influence of environmental factors on the size of the human brain, but the correlation is relatively weak. When Homo sapiens live in places with less vegetation (such as open grasslands), the brain size is usually larger. People living in these habitats usually hunt large animals for food, and these complex tasks may have driven the evolution of the brain. However, the researchers also pointed out that environmental factors have a much greater impact on body size than on the brain.