Climate changes have affected human body and brain size, 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 lineage is Homo sapiens sapiens, meaning modern humans today, which has a much greater 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. The Nature Connections It is clear from what they found: there is a close relationship between temperature and body size, proving that climate played an important role in the evolution of body size during this period.

“The colder it is, the more people are. The bigger you are, the bigger your body is, you produce more heat, but you lose relatively less because your body surface doesn’t expand as much,” he says. Watchman Manuel Welt, an expert at the University of Tübingen, is the study’s lead author.

The relationship between climate and body weight is consistent with Bergmann’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.

Nick Longrich, of the University of Bath’s Milner Evolution Center, who was not involved in the research, said.

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Stability is important for the brain

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 is subject to different evolutionary stresses and is increasing for different reasons.

Scientists came to the conclusion that temperature alone has no effect on brain size, but stability is the deciding 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 point to the future, and we can learn from it. But we cannot draw simple conclusions. While we are now seeing a warming climate, we cannot conclude from this that people’s bodies are shrinking more and more because of this.”

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