Human Body Size Shaped By Climate, Evolutionary Study Shows
The Guardian, July 8, 2021. Research combines data from fossils with climate models, revealing the effect of climate on body and brain size.
A well-known pattern in human evolution is an increase in body and brain size. Our species, Homo sapiens, is part of the Homo genus and emerged about 300,000 years ago. We are much bigger than earlier Homo species and have brains three times larger than humans who lived a million years ago.
There has been debate over the factors causing humans to evolve in this way, prompting a research team led by Cambridge University and Tübingen University in Germany to combine data on more than 300 human fossils from the Homo genus with climate models to establish the role the climate played in driving evolution.
The team determined what temperature, precipitation and other climate conditions each of the fossils, spanning the last million years, would have experienced when it was a living human. The study, published in Nature Communications, found a strong link between temperature and body size, showing that climate was a key driver of body size during that period. The colder it gets, the bigger the humans are,” said Dr Manuel Will, a Tübingen University researcher and joint first author on the study.
“If you’re bigger, you have a bigger body – you are producing more heat but losing relatively less because your surface is not expanding at the same rate.” This relationship between climate and body mass is consistent with Bergmann’s rule, which predicts a larger bodyweight in colder environments and a smaller bodyweight in warmer environments. This is observed in animal species such as bears...
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https://www.theguardian.com/science/2021/jul/08/human-body-size-shaped-by-climate-evolutionary-study-shows
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