Climate changes have affected the size of the human body and brain, according to a new evolutionary study that compared data from 300 fossils with climate models.
The species Homo sapiens evolved about 300,000 years ago within the human genus, Homo. Its subspecies is Homo sapiens sapiens, meaning modern man today, which has a much larger stature and three times the brain of humans who lived a million years ago.
There has long been a debate about the factors that have supported human development in this direction.
Scientists at the University of Cambridge and the University of Tübingen used 300 studied fossils, which date back about one million years, to determine the temperature, amount of precipitation and other climatic conditions that characterized an individual’s life conditions.
Their findings were published in the scientific journal Nature Communications. They concluded that there is a close relationship between temperature and body size, proving that climate played an important role in shaping body size during this period, the Guardian wrote.
“The colder it is, the more people are,” said Manuel Weil, an expert at the University of Tübingen, lead author of the study.
The relationship between climate and body weight is consistent with Bergman’s rule of biogeography that body weight is higher in cold environments. This can be seen, for example, in species such as bears: Arctic polar bears, for example, are much heavier than brown bears in warmer climates.
“This is not entirely a surprising finding, but it is interesting to see that in this respect, our evolution is not very different from that of other mammals,” said Nick Longrich, of the University of Bath’s Milner Evolution Center, who was not involved in the matter. in search.
The study also found an association between brain size and climate, but the results showed that environmental factors have a much smaller impact on brain size than body size. This proves that brain and body size are under different evolutionary stresses and increase for different reasons.
Scientists came to the conclusion that temperature has no effect on brain size, but stability is the determining factor: a more stable climate results in a larger brain.
It takes a lot of energy to run a big brain. Will said that in a stable environment, there is more food on a permanent basis, so there will likely be enough nutrients available to meet energy needs.
There were also indications that behavioral changes, such as the use of hunting strategies, might affect brain size. These indirect factors shed light on how complex processes led to human evolution.
Weil noted that evolution continues, but today there are factors other than a million years ago. The past can indicate the future, and we can learn from it. But we cannot draw simple conclusions. Since we are now seeing a warming climate, we cannot conclude from this that people’s bodies will get smaller and smaller as a result,” says Will. (MTI)
