Turbulent era sparked leap in human behavior, adaptability 320,000 years ago

 

New drill core shows a boom-bust landscape in the east African rift valley at a defining moment in human evolution, technology and culture

For hundreds of thousands of years, early humans in the East African Rift Valley could expect certain things of their environment. Freshwater lakes in the region ensured a reliable source of water, and large grazing herbivores roamed the grasslands. Then, around 400,000 years ago, things changed. The environment became less predictable, and human ancestors faced new sources of instability and uncertainty that challenged their previous long-standing way of life.

The first analysis of a new sedimentary drill core representing 1 million years of environmental history in the East African Rift Valley shows that at the same time early humans were abandoning old tools in favor of more sophisticated technology and broadening their trade networks, their landscape was experiencing frequent fluctuations in vegetation and water supply that made resources less reliably available. The findings suggest that instability in their surrounding climate, land and ecosystem was a key driver in the development of new traits and behaviors underpinning human adaptability.

In the Oct. 21 issue of the journal Science Advances, an interdisciplinary team of scientists led by Richard Potts, director of the Human Origins Program at the Smithsonian's National Museum of Natural History, describes the prolonged period of instability across the landscape in this part of Africa (now Kenya) that occurred at the same time humans in the region were undergoing a major behavioral and cultural shift in their evolution.

Potts and colleagues documented this behavioral and cultural shift in 2018 based on artifacts recovered at an archaeological site known as Olorgesailie. Decades of study at Olorgesailie by Potts' team and collaborators at the National Museums of Kenya have determined that early humans at Olorgesailie relied on the same tools, stone handaxes, for 700,000 years. Their way of life during this period was remarkably stable, with no major changes in their behaviors and strategies for survival. Then, beginning around 320,000 years ago, people living there entered the Middle Stone Age, crafting smaller, more sophisticated weapons, including projectiles. At the same time, they began to trade resources with distant groups and to use coloring materials, suggesting symbolic communication. All these changes were a significant departure from their previous lifestyle, likely helping early humans cope with their newly variable landscape, Potts said.

"The history of human evolution has been one of increasing adaptability," Potts said. "We come from a family tree that's diverse, but all of those other ways of being human are now extinct. There's only one of us left, and we may well be the most adaptable species that may have ever existed on the face of the Earth."

While some scientists have proposed that climate fluctuations alone may have driven humans to evolve this remarkable quality of adaptability, the new study indicates the picture is more complicated than that. Instead, the team's analysis shows that climate variability is but one of several intertwined environmental factors that drove the cultural shift they described in 2018. The new analysis reveals how a changing climate along with new land faults introduced by tectonic activity and ecological disruptions in the vegetation and fauna all came together to drive disruptions that made technological innovation, trading resources and symbolic communication¬--three key factors in adaptability--beneficial for early humans in this region.

In seeking to understand the major evolutionary transition they had uncovered at Olorgesailie, Potts and his team had been frustrated by a large gap in the region's environmental record. Erosion at Olorgesailie, a hilly area full of sedimentary outcrops, had removed the geologic layers representing some 180,000 years of time at exactly the period of this evolutionary transition. To learn about how the region changed during that period, they had to look elsewhere.

They arranged to have a Nairobi company drill in the nearby Koora basin, extracting sediment from as deep into the earth as they could. The drill site, about 15 miles from the archaeological dig sites, was a flat, grassy plain, and the team had no clear idea what was beneath its surface. With the involvement and support from the National Museums of Kenya and the local Oldonyo Nyokie community, a 139-meter core was removed from the earth. That cylinder of earth, just four centimeters in diameter, turned out to represent 1 million years of environmental history.

Colleagues in the National Museum of Natural History's Human Origins Program and Department of Paleobiology and dozens of collaborators at institutions worldwide worked to analyze the environmental record they had obtained, which is now the most precisely dated African environmental record of the past 1 million years. Charting radioisotope ages and changes in chemical composition and deposits left by plants and microscopic organisms through the different layers of the core, the team reconstructed key features of the ancient landscape and climate across time.

They found that after a long period of stability, the environment in this part of Africa became more variable around 400,000 years ago, when tectonic activity fragmented the landscape. By integrating information from the drill core with knowledge gleaned from fossils and archeological artifacts, they determined that the entire ecosystem evolved in response.

The team's analysis suggests that as parts of the grassy plains in the region were fragmented along fault lines due to tectonic activity, small basins formed. These areas were more sensitive to changes in rainfall than the larger lake basins that had been there before. Elevated terrain also allowed water runoff from high ground to contribute to the formation and drying out of lakes. These changes occurred during a period when precipitation had become more variable, leading to frequent and dramatic fluctuations in water supply.

With the fluctuations, a broader set of ecological changes also took place. The team found that vegetation in the region also changed repeatedly, shifting between grassy plains and wooded areas. Meanwhile, large grazing herbivores, which no longer had large tracts of grass to feed on, began to die out and were replaced by smaller mammals with more diverse diets.

"There was a massive change in the animal fauna during the time period when we see early human behavior changing," Potts said. "The animals also influenced the landscape through the kinds of plants that they ate. Then with humans in the mix, and some of their innovations like projectile weapons, they also may have affected the fauna. It's a whole ecosystem changing, with humans as part of it."

Finally, Potts notes that while adaptability is a hallmark of human evolution, that does not mean the species is necessarily equipped to endure the unprecedented change Earth is now experiencing due to man-made climate change and Anthropogenic biodiversity loss. "We have an astonishing capacity to adapt, biologically in our genes as well as culturally and socially," he said. "The question is, are we now creating through our own activities new sources of environmental disruption that will continue to challenge human adaptability?"

Bronze Age herders were less mobile than previously thought

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IMAGE: GRAZING ANIMALS ON CAUCASUS MOUNTAIN PASTURES. view more 

CREDIT: SABINE REINHOLD

Bronze Age pastoralists in what is now southern Russia apparently covered shorter distances than previously thought. It is believed that the Indo-European languages may have originated from this region, and these findings raise new questions about how technical and agricultural innovations spread to Europe. An international research team, with the participation of the University of Basel, has published a paper on this topic.

During the Bronze Age (ca. 3900 - 1000 BCE), herders and their families moved across the slopes of the Caucasus and the steppes to the north, taking their sheep, goats and cattle with them. It is believed that the Indo-Germanic groups, who brought the Indo-European languages and technical innovations such as wagons, domestic horses and metal weapons to Europe, may have originated from this region.

Until now, experts assumed that this transfer of technology was based on the long-distance migrations and trade contacts of these mobile pastoral communities, and that this mobility connected the Middle East with Europe. An international research team, with the participation of the University of Basel, has now questioned whether these communities did actually travel over such long distances. They published their study in the journal Plos One.

Nutrition reveals low levels of mobility

The researchers reconstructed the diet of the Bronze Age pastoral societies in order to draw conclusions about their migration. Their analysis was based on skeletal remains from burial mounds and flat grave cemeteries on the plateaus of the Caucasus and the steppes bordering to the north. "These human bones and teeth are archaeological treasures," says the study's author Professor Kurt Alt, visiting professor at the University of Basel and professor at Danube Private University in Krems. "They are fundamental resources for gaining a deeper understanding of economic strategies, the mobility patterns associated with them and social differentiation."

The research team analyzed the isotopic composition of carbon and nitrogen in bone collagen from the skeletal remains of 150 people, taken from eight sites. The finds date back to a period from about 5000 to about 500 BCE. In addition, the scientists compared this data with the isotope ratios in the bone collagen of 50 animals, as well as with the local vegetation of that time. The isotope ratios in bone collagen reflect the isotope ratios in the main foodstuffs that a person eats.

As it turns out, the diets of these groups were mainly based on the foodstuffs within the landscapes where their remains were found. "The communities apparently remained within their respective ecological areas and did not switch between the steppes, forest steppes or higher regions," explains Sandra Pichler from the Department of Environmental Sciences at the University of Basel, co-author of the study. According to the isotope analysis, meat, milk and dairy products formed a large part of these individuals' basic diets, but they were supplemented by wild plants, too. It was not until the end of the Bronze Age that their diets began to be based more on cultivated cereals, with millet presumably the main crop in this regard.

Technology transfer by word of mouth

"This study's findings imply that Caucasian communities were not highly mobile and did not undertake large-scale migrations, suggesting that the revolutionary technical innovations of the 4th and 3rd millennium BCE, such as wagons or metal weapons, were transmitted in other ways."

If the pastoral communities of the time only moved across shorter distances, technologies could have been passed on from one group to the next transmitting the knowledge of metal weapons, the processing of bronze and the domestication of horses into Europe by word of mouth.

Stone Weight Used in Commerce During First Temple Period Discovered Near Western Wall in Jerusalem

JERUSALEM — A limestone weight that dates to the First Temple era and may have been used in marketplace commerce or for the acquirement of animals to sacrifice was recently discovered in Jerusalem during a soil sift from an excavation near the Western Wall.

The weight, inscribed with a symbol representing the word “shekel,” was found while archaeologists wet-sifted soil from a landfill area as part of a joint project between the Israel Antiquities Authority and the Western Wall Heritage Foundation.

“The weight is dome-shaped with a flat base. On the top of the weight is an incised Egyptian symbol resembling a Greek gamma (γ), representing the abbreviated unit ‘shekel.’ Two incised lines indicate the double mass: two shekalim,” excavation directors Dr. Barak Monnickendam-Givon and Tehillah Lieberman outlined in a statement.

They explained that as coins were not yet invented, the shekel was used as the weight system in Israel. The weight that was found equates to two shekels.

New evidence found of the ritual significance of a classic Maya sweat bath in Guatemala

SMITHSONIAN TROPICAL RESEARCH INSTITUTE

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IMAGE: AN ASSORTMENT OF TOAD BONES WAS PLACED IN THE LOS SAPOS SWEAT BATH OFFERING. view more 

CREDIT: SAN BARTOLO-XULTUN REGIONAL ARCHAEOLOGICAL PROJECT

Sweat baths have a long history of use in Mesoamerica. Commonly used by midwives in postpartum and perinatal care in contemporary Maya communities, these structures are viewed as grandmother figures, a pattern that can also be traced to earlier periods of history. At the site of Xultun, Guatemala, a Classic Maya sweat bath with an unusual collection of artifacts led archaeologists from the Smithsonian Tropical Research Institute (STRI), the Archaeology Program at Boston University and other collaborating institutions to gather new evidence of these beliefs and an early example of the related ritual practices.

Indigenous people of Mesoamerica see the natural world as a place populated by ancestors and supernatural beings, many of whom live within natural features and ancient buildings. This was certainly the case for the Classic Maya. Dating to the Early Classic period (250-550 A.D.), the sweat bath at Xultun, named Los Sapos, appears to have been embodied by an amphibian goddess. Outside the sweat bath, the scientists encountered a representation of this little-known Classic Maya deity, possibly "ix.tzutz.sak." The goddess is depicted squatting in a toad-like position with legs ornamented with iguanas and cane toads (Rhinella marina).

"No other structure in Mesoamerica--sweat bath or otherwise--looks like this building," said STRI archaeologist Ashley Sharpe, co-author of the study. "It would seem that when someone enters the front of the structure, they are entering the amphibian goddess who personified the sweat bath."

"Although this goddess' name remains undeciphered, proposed readings suggest she was responsible for gestation cycles, both of time and human life," said Boston University archaeologist Mary Clarke, main author of the study. "Linking notions of birth to reptilian figures, however, is not uncommon among the Classic Maya as they express the verb 'to birth' as an upended reptilian mouth glyph. What we see at Xultun is an example where this reptilian goddess, as well as the ideas and myths she embodied, are expressed as a physical place."

The Los Sapos sweat bath was an active part of the Xultun community for about 300 years. Around 600 A.D. an adult individual was interred within the doorway, after which the entire building was buried, even though the Maya continued living at Xultun for several more centuries. About 300 years later, the buried building was revisited, the majority of human remains removed and a new and unusual offering was presented to the structure, including a human child, juvenile animals including a puppy and birds, several complete cane toads and iguanas, and numerous stone tools and ceramic sherds.

The deposited items had varying degrees of heat damage. The Maya built a fire within the vacated tomb, where they began placing their offerings. For the authors, the selection of artifacts may have been associated with the sweat bath's identity as a grandmother figure and the early understanding of the structure as a place of birth and human creation.

"Maya archaeologists often find artifact concentrations like these that were likely dedications to structures, but there is rarely an obvious link between the objects and the structure," Sharpe said. "Because of the iconography on the outside of Los Sapos and because we know it was a sweat bath, we have a rare case where we can associate the offerings--an infant, figurines of women, and frogs and iguanas--with the role the structure played in the community."

The Los Sapos deposit suggests that the sweat bath's historical role in Xultun continued centuries after the building had been buried. As the goddesses related to sweat baths throughout Mesoamerican history are described as holding sway over the conditions for life on Earth, the offering was likely an attempt at requesting assistance from the goddess embodying the Los Sapos structure. This could have been a last effort to please the supernatural entity and prevent losing hold of their lands, which were abandoned soon after, around the Maya Collapse of 900 A.D.

"This supernatural figure is a ferocious embodiment of the Earth," Clarke said. "When displeased, she may take revenge or withhold the things people need to survive. The offering at Los Sapos was both an attempt to appease this goddess and an act of resilience. Rather than seeing a population succumbing to collapse, we see them trying to negotiate with this goddess for their survival."

Tradition of petrified birds in the Dome of the Rock

Solomon and the petrified birds

UNIVERSITY OF CHICAGO PRESS JOURNALS

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IMAGE: THE BIRDS ON THE DOME OF THE ROCKview more 

CREDIT: PHOTO: ELON HARVEY.

On the southern exterior wall of the Dome of the Rock, a very important Islamic shrine in Jerusalem's Old City, there are two marble slabs, both carved from the same stone and placed side by side to form a symmetrical pattern, that depicts two birds. In a recent article published in the Journal of Near Eastern Studies, "Solomon and The Petrified Birds on the Dome of the Rock," author Elon Harvey explores the history of this marble decoration and describes how different narratives about Solomon and two birds contributed to the multiple understandings of this imagery.

According to this article, there are six factors that contribute to the significance of the birds' imagery: (1) it breaks the symmetry that characterizes the Dome of the Rock's southern wall; (2) it is placed in the southern entrance, which is the main entrance to the Dome of the Rock; (3) there are no other depictions of animals or living creatures on the Dome of the Rock; (4) the imagery bears resemblance to carved depictions of birds in Frankish structures in the region; (5) the imagery has remained in the same spot for at least 350 years in spite of extensive renovations; and (6) the techniques for producing symmetrical imagery from marble point suggest a Byzantine and, perhaps, Christian origin.

In terms of narratives that describe the significance of the two birds, the earliest account is attributed to Evliya Celebi in 1672, who described it as an imagery that shows a "miracle of God." In the 18th century, Elzear Horn, a Franciscan missionary, described local accounts that tells the story of a stonecutter who found the two birds "formed... by nature itself."

A main departure from these two accounts, however, is found in later narratives that emphasize the story of Solomon and the two birds. Two 19th century accounts by Lievin de Hamme and Ermette Pierotti, respectively, describe the birds as magpies who defied Solomon's orders to contribute to the building of the Temple, and, as a result, were petrified as a punishment. In the beginning of the 20th century, James Edward Hanauer noted a local tale that describes how Solomon punished a male bird for boasting to a female bird: because the male bird boasted that he himself could tear down all of Solomon's edifices, Solomon turned both birds into stone. Later on, Haim Schwarzbaum, a 20th century folklorist, demonstrated that Hanauer's tale is a narrative with Sufi origins dating back to the beginning of the 10th century CE.

According to this article, however, Schwarzbaum's work points towards older Sufi narratives that date back to, at the latest, the 9th century C.E. These Sufi narratives are recorded by three figures: al-Qushayr, al-Kahra'iti, and Abu Tahir al-Silafi. In these versions, the birds were not petrified as a punishment. Rather, even after a male bird boasted to a lover that he can single-handedly topple the Dome of Solomon, Solomon acknowledged the bird's plea that the words of lovers should not be held against them. Afterall, those attempting to impress their love interests tend to get carried away with their words.

In conclusion, this article suggests that the legend of Solomon and the birds developed over time until it was finally associated with the Dome of the Rock. As the author argues, stories about the two birds demonstrate that "Sufi traditions and the figure of Solomon were still very influential in shaping the appearance and conception of the Dome of the Rock."

Medieval plague outbreaks picked up speed over 300 years

 McMaster University researchers who analyzed thousands of documents covering a 300-year span of plague outbreaks in London, England, have estimated that the disease spread four times faster in the 17th century than it had in the 14th century.

The findings, published today in the Proceedings of the National Academy of Sciences, show a striking acceleration in plague transmission between the Black Death of 1348, estimated to have wiped out more than one-third of the population of Europe, and later epidemics, which culminated in the Great Plague of 1665.

Researchers found that in the 14th century, the number of people infected during an outbreak doubled approximately every 43 days. By the 17th century, the number was doubling every 11 days.

"It is an astounding difference in how fast plague epidemics grew," says David Earn, a professor in the Department of Mathematics & Statistics at McMaster and investigator with the Michael G. DeGroote Institute for Infectious Disease Research, who is lead author on the study.

Earn and a team including statisticians, biologists and evolutionary geneticists estimated death rates by analyzing historical, demographic and epidemiological data from three sources: personal wills and testaments, parish registers, and the London Bills of Mortality.

It was not simply a matter of counting up the dead, since no published records of deaths are available for London prior to 1538. Instead, the researchers mined information from individual wills and testaments to establish how the plague was spreading through the population.

"At that time, people typically wrote wills because they were dying or they feared they might die imminently, so we hypothesized that the dates of wills would be a good proxy for the spread of fear, and of death itself. For the 17th century, when both wills and mortality were recorded, we compared what we can infer from each source, and we found the same growth rates," says Earn. "No one living in London in the 14th or 17th century could have imagined how these records might be used hundreds of years later to understand the spread of disease."

While previous genetic studies have identified Yersinia pestis as the pathogen that causes plague, little is known about how the disease was transmitted.

"From genetic evidence, we have good reason to believe that the strains of bacterium responsible for plague changed very little over this time period, so this is a fascinating result," says Hendrik Poinar, a professor in the Department of Anthropology at McMaster, who is also affiliated with the Michael G. DeGroote Institute for Infectious Disease Research, and is a co-author on the study.

The estimated speed of these epidemics, along with other information about the biology of plague, suggest that during these centuries the plague bacterium did not spread primarily through human-to-human contact, known as pneumonic transmission. Growth rates for both the early and late epidemics are more consistent with bubonic plague, which is transmitted by the bites of infected fleas.

Researchers believe that population density, living conditions and cooler temperatures could potentially explain the acceleration, and that the transmission patterns of historical plague epidemics offer lessons for understanding COVID-19 and other modern pandemics.

This new digitized archive developed by Earn's group provides a way to analyze epidemiological patterns from the past and has the potential to lead to new discoveries about how infectious diseases, and the factors that drive their spread, have changed through time.

Climate change likely drove early human species to extinction

Of the six or more different species of early humans, all belonging to the genus Homo, only we Homo sapiens have managed to survive. Now, a study reported in the journal One Earthon October 15 combining climate modeling and the fossil record in search of clues to what led to all those earlier extinctions of our ancient ancestors suggests that climate change--the inability to adapt to either warming or cooling temperatures--likely played a major role in sealing their fate.

"Our findings show that despite technological innovations including the use of fire and refined stone tools, the formation of complex social networks, and--in the case of Neanderthals--even the production of glued spear points, fitted clothes, and a good amount of cultural and genetic exchange with Homo sapiens, past Homo species could not survive intense climate change," says Pasquale Raia of Università di Napoli Federico II in Napoli, Italy. "They tried hard; they made for the warmest places in reach as the climate got cold, but at the end of the day, that wasn't enough."

To shed light on past extinctions of Homo species including H. habilis, H. ergaster, H. erectus, H. heidelbergensis, H. neanderthalensis, and H. sapiens, the researchers relied on a high-resolution past climate emulator, which provides temperature, rainfall, and other data over the last 5 million years. They also looked to an extensive fossil database spanning more than 2,750 archaeological records to model the evolution of Homo species' climatic niche over time. The goal was to understand the climate preferences of those early humans and how they reacted to changes in climate.

Their studies offer robust evidence that three Homo species--H. erectus, H. heidelbergensis, and H. neanderthalensis--lost a significant portion of their climatic niche just before going extinct. They report that this reduction coincided with sharp, unfavorable changes in the global climate. In the case of Neanderthals, things were likely made even worse by competition with H. sapiens.

"We were surprised by the regularity of the effect of climate change," Raia says. "It was crystal clear, for the extinct species and for them only, that climatic conditions were just too extreme just before extinction and only in that particular moment."

Raia notes that there is uncertainty in paleoclimatic reconstruction, the identification of fossil remains at the level of species, and the aging of fossil sites. But, he says, the main insights "hold true under all assumptions." The findings may serve as a kind of warning to humans today as we face unprecedented changes in the climate, Raia says.

"It is worrisome to discover that our ancestors, which were no less impressive in terms of mental power as compared to any other species on Earth, could not resist climate change," he said. "And we found that just when our own species is sawing the branch we're sitting on by causing climate change. I personally take this as a thunderous warning message. Climate change made Homo vulnerable and hapless in the past, and this may just be happening again."

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