Drill core site. To understand the major evolutionary transition they discovered in Olorgecili in 2018, Pots and his team were disappointed by the large gap of 180,000 years in the area’s environmental record. To find out how the field changed during that period, he had to look elsewhere. They arranged for the Nairobi Company to conduct an exercise in the nearby Kura Basin, where they sank the earth as deeply as possible. The exercise site was a flat, grassy field about 15 miles from archaeological dig sites, and the team had no clear idea of what was beneath its surface. With the involvement and support of Kenya’s national museums and the local Oldnoyo Nyoki community, the 139-meter core was removed from Earth. That Earth’s cylinder, only four centimeters in diameter, turned out to represent 1 million years of environmental history. Credit: Human Origins Program, Smithsonian
The new exercise core shows a boom-bust landscape at a defined moment of human evolution, technology and culture in the East African Raft Valley.
For hundreds of thousands of years, early humans in the East African Rift Valley could expect certain things from their environment. Freshwater ponds in the region ensure a reliable source of water, and large grazing herbivores roam the meadows. Then, about 400,000 years ago, things changed. The environment became less predictable, and human ancestors faced new sources of instability and uncertainty that challenged their earlier long way of life.
The first analysis of a new silt drill representing 1 million years of environmental history in the East African Rift Valley shows that at the same time early men were abandoning old equipment in favor of more modern technology and expanding their trade network, experiencing their landscape and water. Frequent fluctuations in supply make resources less reliably available. The findings suggest that instability in the surrounding climate, soil and ecosystem was a major driver in the development of new traits and behaviors taking into account human adaptability.
Transition from stone hand ax to new technology. Pots and colleagues have documented a major behavioral and cultural shift in humans in 2018, based on artefacts obtained at an archaeological site in modern Kenya called Olorgesili. Based on a decades-long study of Olorgesicili by Potts’ team and colleagues at Kenya’s National Museums, it has been determined that the earliest humans of Olorgesicili relied on the same tools, stone hand axes, for 700,000 years. Then, about 60,000,000,000 years ago, the people who lived there entered the Middle Stone Age, in which smaller, more practical weapons were made, including artillery. At the same time, they began to trade resources with distant groups and use colored materials, suggesting symbolic communication. Credit: Human Origins Program, Smithsonian
The October 21, 2020 issue of the Journal Science progress, An interdisciplinary team of scientists led by Richard Pots, director of the Human Origins program at the Smithsonian National Museum of Natural History, describes the long period of instability in the landscape in this part of Africa (now Kenya) that led to the simultaneous evolution of Were living.
Pots and colleagues have documented this behavioral and cultural shift based on artefacts obtained in 2018 at an archaeological site called O Largesili. Based on a decades-long study of Olorgesicili by Pots’ team and colleagues at the National Museums of Kenya, it has been determined that the early humans of Olorgesicili relied on the same tools, stone handhelds, for 700,000 years. Their lifestyle was significantly stabilized during this period, without any major changes in their behaviors and survival strategies. Then, some 350,000 years ago, the inhabitants of the Middle Stone Age developed smaller, more sophisticated weapons, including those of the Middle Ages. At the same time, they began to trade resources with distant groups and use colored materials, suggesting symbolic communication. Potts said all of these changes were a significant departure from their previous lifestyles, possibly helping early early men cope with their new variable landscape, Potts said.
“The history of human evolution has been one of increasing adaptability,” Pots said. “We came from a family tree that is diverse, but all those other ways of becoming human are now extinct. Only one of us has survived, and we may have the most adaptive species on the face of the earth. ”
Drill core. The team’s analysis suggests that due to tectonic activity parts of the area’s meadows were fragmented with defective lines, forming small basins. These areas were sensitive to changes in rainfall as the shores of large lakes were previously. Elevated terrain also allowed the flow of water from the ground to contribute to the formation and drying of ponds. These changes occurred during a period when rainfall became more variable, causing frequent and dramatic fluctuations in water supply. With the fluctuations, a broad set of ecological changes also took place. The team found that the vegetation in the region also changes frequently, between grasslands and wooded areas. Meanwhile, large grazing herbivores, which no longer had large parts of grasslands, began to die out and were replaced by smaller mammals with more diverse diets. The findings suggest that instability in the surrounding climate, soil and ecosystem was a major driver in the development of new traits and behaviors taking into account human adaptability. Credit: Human Origins Program, Smithsonian; Core Image courtesy Lackcore, University of Minnesota.
While some scientists have proposed that climate change alone could motivate humans to develop this remarkable quality of adaptability, a new study suggests that the picture is more complex than that. Instead, the team’s analysis shows that there is climate variability, but it is one of the interconnected environmental factors that led to the cultural shift they described in 2018. The new analysis reveals that with the new land defects introduced by tectonic activity and environmental disruptions in flora, the changing environment and fauna came together to drive all disruptions that brought technological innovation, trade resources and symbolic communication – the three main areas of adaptability – Beneficial for early humans.
In order to understand the major evolutionary transition they had discovered in Olorgasili, Pots and his team were frustrated by the large gap in the area’s environmental record. The erosion of the Lor Lorgaceli, a hilly area filled with alluvial outfrops, during a certain period of this evolutionary transition, removed the geographical layers showing a time of about 180,000 years. To find out how the field changed during that period, he had to look elsewhere.
They arranged for the Nairobi Company to conduct an exercise in the nearby Kura Basin, sinking the earth as deep as they could. The exercise site was a flat, grassy field about 15 miles from archaeological dig sites, and the team had no clear idea what was beneath its surface. With the involvement and support of Kenya’s National Museum and the local Oldnoyo Nyoki community, the 139-meter core was removed from Earth. That Earth’s cylinder, only four centimeters in diameter, turned out to represent 1 million years of environmental history.
Dozens of collaborators from the Human Origins Program of the National Museum of Natural History and the University of Palebiology worked to analyze the environmental records they received, the most accurate African environmental record of the last 1 million years. With the Charding Radioisotope era and changes in chemical composition and deposits by the various layers of roots left by plants and microscopic organisms, the team reconstructed the ancient landscape and the main characteristics of the climate over time.
They found that after a long period of stability, the environment in this part of Africa became more variable about 400,000 years ago, when tectonic activity shattered the landscape. By integrating information from the core of the exercise with knowledge gained from fossils and archeological artefacts, they determined that a complete ecosystem had evolved in response.
The team’s analysis suggests that due to tectonic activity parts of the area’s meadows were fragmented with defective lines, forming small basins. These areas were sensitive to changes in rainfall, as were the shores of large lakes that preceded it. Elevated terrain also allowed the flow of water from the ground to contribute to the formation and drying of ponds. These changes occurred during a period when rainfall became more variable, causing frequent and dramatic fluctuations in water supply.
With the fluctuations, a broad set of ecological changes also took place. The team found that the vegetation in the region also changes frequently, changing between meadows and wooded areas. Meanwhile, large grazing herbivores, which no longer had large parts of grasslands, began to die out and were replaced by smaller mammals with more diverse diets.
“Animals underwent major changes during the period when we see early human behavior changing,” Pots said. “Animals also affect the landscape through the types of plants they take. Then there are humans and some of their innovations in the mix, such as projectiles, they have also affected the fauna. It is a whole ecosystem changing, with humans as part of it. “
Finally, Pots notes that adaptability is a feature of human evolution, not that species are equipped to withstand unprecedented change, the Earth is now experiencing man-made climate change and the loss of anthropogenic biodiversity. “We have an amazing ability to adapt to our genes as well as biologically and culturally and socially,” he said. “The question is, are we now creating new sources of environmental disruption through our own activities that will continue to challenge human adaptability?”
References: Richard Potts, Renee Domin, Jessica W. Mormon, Anna K. Behrensmeyer, Alan L. Dino, Simon Riddle, Emily J. Beverly, Eric T. Brown, “Increasing Ecological Resource Variability during the Critical Transition to Hominine Evolution.” Daniel Diokmpo, Rahab Kinnyjui, Rachel Lupian, R. Burnhart en Van, Nathan R. Rab Bidex, James M. J. Russell, Mona Stoke. , Andrew S. Cohen, C. Brahnin Keller, John King, Naomi E. Levin, Christina Brady Schwannon, Veronica Maruri, Robin W. Renout, Stephen M. Russina and Kevin Uno, 21 October 2020, Science progress.
DOI: 10.1126 / sciadv.abc8975
Funding for this research was provided by William H. Provided by the Donor Foundation and the Peter Buck Fund for the Human Origins Program of the National Museum of Natural History.
