Of the six or more different species of early humans, all of the Homo genus, only we Homo sapiens survived. A study published October 15 in the journal One Earth, combining climate modeling and fossil records in search of clues to the earlier extinctions of our ancient ancestors, suggests that climate change – the inability to adapt to warming or cooling – Adjust temperatures likely played an important role in sealing their fate.
“Our results show that despite technological innovations, including the use of fire and nifty stone tools, complex social networks are being formed and – in the case of Neanderthals – even making glued spearheads, custom clothing, and a good amount of culture and genetic exchange with Homo sapiens, earlier homo species could not survive the intense climate change, ”says Pasquale Raia from the Università di Napoli Federico II in Napoli, Italy. “You have tried very hard; They made their way to the warmest places within reach when the climate turned cold, but at the end of the day that wasn't enough. "
To shed light on the extinction of earlier homo species such as H. habilis, H. ergaster, H. erectus, H. heidelbergensis, H. neanderthalensis and H. sapiens, the researchers relied on a high-resolution climate emulator in the past that provides temperature, Precipitation and other data over the past 5 million years. They also searched an extensive fossil database for more than 2,750 archaeological records to model the evolution of the climatic niche of the homo species over time. The aim was to understand the climate preferences of these early humans and how they responded to climate change.
Their studies provide robust evidence that three homo-species – H. erectus, H. heidelbergensis, and H. neanderthalensis – lost a significant part of their climatic niche shortly before extinction. They report that this decline coincided with severe, adverse changes in global climate. In the case of the Neanderthals, competition with H. sapiens probably made matters worse.
"We were surprised by the regularity of the effects of climate change," says Raia. "It was crystal clear that for the extinct species and only for them the climatic conditions shortly before extinction and only at that particular moment were simply too extreme."
Raia notes that the paleoclimatic reconstruction, the identification of fossil remains at the species level, and the aging of fossil sites are uncertain. But, he says, the most important findings “apply under all conditions”. The results could serve as a kind of warning to humans today as we face unprecedented climate change, says Raia.
"It is worrying to discover that our ancestors, no less impressive in their mental powers than any other species on earth, have not been able to withstand climate change," he said. "And we've found that just when our own species are sawing the branch we're sitting on, we're causing climate change. Personally, I take that as a thundering warning message. Climate change has made homo vulnerable and unhappy in the past, and this is it." could happen again. "
This work was supported by MCTIC / CNPq / FAPEG.
One Earth, Raia et al .: "The extinction of homo species in the past coincided with an increased vulnerability to climate change." Https://www.cell.com/one-earth/fulltext/S2590-3322(20) 30476-0
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