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 that there is a connection between astronomical climate change and human evolution.
The group of experts in climate modeling, anthropology, and ecology has combined the most comprehensive database of relatively truth-dated fossil remains and archaeological artifacts with an unprecedented new computer model that simulates 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 stated above; in fact, there was already a widespread belief that climate change may have affected human evolution; however, it was rather 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, compared to the archaeological record.
This resulted in the environmental conditions favored by different hominin clusters: Homo sapiens, Homo neanderhalensis, Homo heidelbergensis, Homo erectus, and early African Homo. Starting from this, the group then searched for all the places and times in the model where these conditions occurred, creating evolving maps of potential hominin habitats over time.
author of the study, Axel Timmermann, Director of the IBS Center for Climate Physics (ICCP) at Pusan National University in South Korea on the issue, said, “Although different archaic human clusters prefer different climatic environments, all of their habitats are It responded to the climate changes caused by the astronomical changes in the wobble, tilt and orbital eccentricity in its axis, with time scales changing in the middle of 21 to 400 thousand years.
Hominin clusters were found to have valuable differences in their preferred habitats
The research group, which wanted to test the robustness of the contact between climate and human habitats, determined the ages of the fossils as a stack of paper. He repeated his analysis with stirring. If the past evolution of climate variables had not affected where and when humans lived, then this would mean that both methods should result in the same habitats.
However, when using mixed and realistic fossil ages, the researchers found valuable differences in habitat patterns in the three most recent hominin clusters (Homo sapiens, Homo neanderthalensis and Homo heidelbergensis). Regarding this, Timmermann noted, “This result indicates 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 hominin clusters lived and where their remains were found.”
The researchers’ next question was whether the habitats of different human types overlap in space and time. At this point, past contact sites provided invaluable information about potential medical sequences 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’ roots can be traced back to South African populations of Homo heidelbergensis about 300 thousand years ago. .
One of the co-authors of the research, IBS Center for Climate Physics and postdoctoral research assistant Dr. Jiaoyang Ruan said, “Our climate-based reconstructing of hominid ancestry is very similar to recent predictions from genetic data or analysis of morphological differences in human fossils, which increases our confidence in the results.”
“We are where we are now because we managed to adapt to the slow changes in the past climate”
On the other hand, the simulation in question; It is said to be the first simulation ever to have a state-of-the-art climate model that covers the growth and reduction of ice layers, the world’s last 2 million years of environmental history representing climate reactions to changes in greenhouse gas concentrations in the past, and the obvious transition in the frequency of glacial cycles about 1 million years ago.
The co-author of the study from the University of Zurich, Prof. “Until now, the paleoanthropology community has not always harnessed the full potential of paleoclimate model simulations for this genus. Our work clearly demonstrates the value of validated climate models enough 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 types to address the question of how humans might have adapted to changing food sources over the past 2 million years. Co-author of the study, Elke Zeller, a doctoral student at Pusan Ulusak University, said: “When we looked at the information on the five large hominin clusters, we discovered a different pattern. About 2 million years ago, early African hominins preferred stable climatic conditions. This makes them relatively narrowly habitable. Approximately 800,000 years ago, following a major climate shift, a cluster known under the umbrella of Homo heidelbergensis adapted to a much wider range of food sources, enabling them to become global travelers and reach 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 in the form we are in now because we have been able to adapt to slow changes in climate in the past for more than a thousand years,” and his work is proof of the role of climate change in human evolution. underlined.