This is how hominins adapted to a changing world two million years ago

The diversity that helped humans dominate the world appeared very early in our evolutionary history, according to sediments and stone tools from the Olduvai Gorge in Tanzania.

Olduvai provided some of the oldest tools and fossils known from our species, to turn down. A recent study points to environmental evidence buried in the sediments. The results indicate that our first relatives were equipped to adapt to new environments about two million years ago.

It seems that this was a basic ability that allowed our relatives to go global. 1.7 million years ago, an early human relative came into contact Standing man It has spread far beyond Africa and throughout most of Asia, even Indonesia. They arrived in Western Europe 1.2 million years ago. During their travels, hominins encountered environments very different from those in which their ancestors originated, such as the tropical forests of Indonesia and the arid plains of Central Asia.

They might have been able to prepare for this simply by staying in one place within Africa. In Ewass Oldupa, a recently excavated site on the edge of the famous Olduvai Strait, the results indicate that early hominins lived in an ever-changing landscape.

Life after a volcano

Our oldest evidence of early human relatives in the Olduvai Gorge is a handful of stone tools, made and used about 2.03 million years ago.

Like other tools discovered in Ewass Oldupa, it is part of the Olduwan complex: relatively simple stone tools made by early hominins such as H. Erect And the H. habilis. Olduwan tools are mostly sharp chips and very basic tools for slicing, scraping and pounding. They are far less complex and precise than tools made by later hominins, such as Neanderthals, who cut small chips from carefully prepared stone cores. But for a few hundred thousand years, Olduwan ready-made tools got the job done.

In Ewass Oldupa, the task was to survive in a landscape of mostly arched fern meadows dotted with some herbs and woody plants, watered by a meandering river. Ferns were perhaps the first plants to set their roots on a wide fan of pumice that sprang from a nearby volcano shortly before. Traces of this landscape are still buried in a layer of sediment about a meter high above the rocky remnants of the ancient lava flow; Paleoanthropologist Michael Petraglia of the Max Planck Institute for the Science of Human History, and his colleagues found fossilized pollen grains and microscopic pieces of fossil plant tissue called phytoliths in the stratum, along with 10 stone tools.

For hunters like H. habilis, Whose fossil remains were discovered a few hundred meters from Ewass Oldupa, the fern basin was a good place to make a living.

The river provided easy access to the water, and the region’s geology provided several sources of stone for tools. Geochemical analysis of the instruments in Ewass Oldupa indicates that the hominins here gathered some of their quartzite locally and ventured as much as 12 kilometers (7.5 mi) for the rest. They seem to have chosen different materials – in some cases as specific as choosing slightly different types of quartzite from different outcrops – for specific tools. (A study last year also suggested that the first tool-makers in our family tree know enough to choose their materials wisely.)

But then, as always, everything changed.

New worlds in the same place

Thousands of years later, the hominins that once fed on the banks of the river did not recognize the landscapes surrounding Iwas Olduba. Fern meadows have given way to a mixture of forests and grassland around the shores of the lake. Microscopic fossils trapped in the sediments indicate that the plant species that formed those forests and grasslands have changed a lot, and coal deposits reveal that forest fires have ravaged the area periodically, helping the patchwork landscape to rearrange itself.

At other points in the long prehistoric times of the area, the lake expanded, muddy sediments on the lake shore hinting at lush landscapes of forests and palm groves. The lake shore later gave way to dry steppes, mostly devoid of trees and grass. Each of these environments presented completely different food, water, supplies, and challenges, but the hominins seemed to keep returning to Ewass Oldupa.

„Over time, these habitats changed sometimes slowly or quickly,“ Petraglia Lars said. „It’s hard to know how quickly hominins will enter the new ecosystems due to the accuracy of the record, but it is clear that they were able to deal with a variety of environments.“

Petraglia and his colleagues found stone tools left by the hominins who lived at the site (possibly H. habilisIntermittent throughout 200,000 years of continuous change. The 565 stone tools, scattered over thousands of years of stratified deposits at the site, do not look like the remnants of a permanent settlement. Instead, the hominins seem to have left the basin several times, perhaps due to sudden environmental change or volcanic eruptions, but have kept coming back.

“There have been a number of volcanic events during a time scale of 235,000 years represented in Ewass Oldupa,” Petraglia told Ars. „Interestingly, the hominins returned to these regions after each of the volcanic eruptions – that is, they did not completely abandon the area.“

Jacks for all trades

And even if the early hunters and gatherers of Ewass Oldupa found later versions of the place quite strange, they would still know the tools people used to stay alive. For nearly 200,000 years, hominins have relied on the same basic tools to deal with fern meadows by the river, the diversity of forests and grasslands, the fertile lake shore, and the dry steppe.

Olduwan’s cutting, scraping and pounding tools were relatively simple, but they were also incredibly versatile. According to Petraglia and colleagues, Olduwan technology provided a general basic tool kit that also worked in a palm grove on the banks of the lake as it did in the dry steppe. Humans have dominated the world because we are public, and workers can adapt to almost anything. Obviously, our early relatives had the same advantage.

Nature Communications2020 DOI: 10.1038 / s41467-020-20176 (About DOIs).