Whether climate change has an impact on human evolution has long been a question that has puzzled scientists. Now, a study by an international team of scientists has found clear evidence of a link between astronomical climate change and human evolution.
The team of climate modelers, anthropologists and ecologists has combined the most comprehensive database of relatively accurate fossil remains and archaeological artifacts with an unprecedented new supercomputer model simulating the Earth’s last 2 million years of climate history. In this way, scientists were able to determine how archaic humans probably lived under environmental conditions.
The environmental conditions in which prehistoric people lived were determined
As we have mentioned above; in fact, there was already a widespread belief that climate change may have affected human evolution; however, it was difficult to determine whether this was true due to insufficient climate records near the sites where human fossils from prehistoric times were found. To overcome this problem, the research team decided to investigate what the climate in computer simulations was like in the times and places where people lived, according to the archaeological record.
This resulted in the environmental conditions favored by different hominin groups, including Homo sapiens, Homo neanderhalensis, Homo heidelbergensis, Homo erectus, and early African Homo. Starting from this, the team then looked for all the places and times in the model where these conditions occurred and created maps of potential hominin habitats that have evolved over time.
Author of the study, Axel Timmermann, Director of the IBS Center for Climate Physics (ICCP) at Pusan National University in South Korea, said, “Although different archaic human groups prefer different climatic environments, all of their habitats are “It responded to climate changes caused by astronomical changes in axis wobble, tilt and orbital eccentricity on time scales ranging from 21 to 400 thousand years.”
It was found that hominin groups differed significantly in their preferred habitats
Wanting to test the robustness of the link between climate and human habitats, the research team determined the ages of the fossils as a stack of paper. repeated their analysis. If past evolution of climate variables had not affected where and when humans lived, then this would mean that both methods should have resulted in the same habitats.
However, when using mixed and realistic fossil ages, the researchers found significant differences in habitat patterns in the three most recent hominin groups (Homo sapiens, Homo neanderthalensis and Homo heidelbergensis). “This result suggests that the actual sequence of past climate change, including glacial cycles, over at least the last 500,000 years, played a central role in determining where different groups of hominins lived and where their remains were found,” Timmermann noted.
The researchers’ next question was whether the habitats of different human species overlap in space and time. At this point, past contact zones provided very important information about potential species successions and mixtures. After analyzing the contact sites, the researchers obtained a hominin pedigree in which Neanderthals and possibly Denisovans descended from the Eurasian Homo heidelbergensis lineage about 500-400 thousand years ago, while Homo sapiens can trace its roots back to South African populations of Homo heidelbergensis about 300,000 years ago. .
Co-author of the study, IBS Center for Climate Physics and postdoctoral research fellow Dr. “Our climate-based reconstruction of hominid lineages is very similar to recent estimates from genetic data or analysis of morphological differences in human fossils, which increases our confidence in the results,” said Jiaoyang Ruan.
“We are the way we are now because we have managed to adapt to the slow changes in the past climate”
On the other hand, the simulation in question; It is the first continuous simulation with a state-of-the-art climate model that covers the Earth’s last 2 million years of environmental history representing climate responses to the growth and reduction of ice sheets, changes in past greenhouse gas concentrations, and the marked shift in the frequency of glacial cycles about 1 million years ago.
Professor of the University of Zurich, co-author of the study. “Until now, the paleoanthropology community has not tapped into the full potential of such continuous simulations of paleoclimate models. Our work clearly demonstrates the value of well-validated climate models to address fundamental questions about our human origins,” said Christoph Zollikofer.
Together, the research team decided to raise the bar even higher, going beyond the question of early human habitats and the times and places of origin of human species to address the question of how humans might have adapted to changing food sources over the past 2 million years. Asked this question, co-author Elke Zeller, a doctoral student at Pusan Ulusak University, said: “When we looked at the data on the five large hominin groups, we discovered an interesting pattern. About 2 million years ago, early African hominins preferred stable climatic conditions. This makes them relatively narrowly habitable. After a major climate shift approximately 800,000 years ago, a group known under the umbrella of Homo heidelbergensis adapted to a much wider range of food sources, enabling them to become global travelers, reaching remote areas in Europe and East Asia. ‘ he replied.
Timmermann said, “Our work documents that climate played a fundamental role in the evolution of our Homo genus. We are the way we are now because we have been able to adapt to slow changes in climate in the past for over a thousand years,” said his work is evidence of the role of climate change in human evolution. underlined.
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