Scientists Link Neanderthal Extinction to Human Diseaseshttps://phys.org/news/2019-11-scientists-link-neanderthal-extinction-human.htmlIn a new study published in the journal
Nature Communications, Greenbaum and his colleagues propose that complex disease transmission patterns can explain not only how modern humans were able to wipe out Neanderthals in Europe and Asia in just a few thousand years but also, perhaps more puzzling, why the end didn't come sooner.
... To understand why modern humans replaced Neanderthals and not the other way around, the researchers modeled what would happen if the suite of tropical diseases our ancestors harbored were deadlier or more numerous than those carried by Neanderthals.
"The hypothesis is that the disease burden of the tropics was larger than the disease burden in temperate regions. An asymmetry of disease burden in the contact zone might have favored modern humans, who arrived there from the tropics," said study co-author Noah Rosenberg, the Stanford Professor of Population Genetics and Society in the School of Humanities and Sciences.
According to the models, even small differences in disease burden between the two groups at the outset would grow over time, eventually giving our ancestors the edge. "It could be that by the time modern humans were almost entirely released from the added burden of Neanderthal diseases, Neanderthals were still very much vulnerable to modern human diseases," Greenbaum said. "Moreover, as modern humans expanded deeper into Eurasia, they would have encountered Neanderthal populations that did not receive any protective immune genes via hybridization."
The researchers note that the scenario they are proposing is similar to what happened when Europeans arrived in the Americas in the 15th and 16th centuries and decimated indigenous populations with their more potent diseases.
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Newly Discovered Motifs in Rock Art in Tumlehed Shows Seafaring in the Stone Agehttps://phys.org/news/2019-11-newly-motifs-art-tumlehed-seafaring.htmlSouth-west Sweden's best preserved rock painting has now been dated—it is from the late Stone Age. With the aid of new technologies, researchers at the University of Gothenburg have been able to reveal a number of previously unknown motifs that are no longer visible to the naked eye. The most important of these newly discovered motifs are boats with elk-head stems. This is the first time that these kinds of boats have been documented in southern or western Scandinavia and these motifs provide further evidence of the long-distance sea voyages undertaken by Stone Age maritime hunters.
... This technology has made it possible for the first time to date the rock painting in Tumlehed. It is from the late Stone Age and was painted some time between 4200-2500 years BCE by mobile hunters who had come by boat to the west coast of Sweden to hunt seal and whales.The new technologies used on the Tumlehed rock painting included the digital image enhancing program Dstretch, which was originally developed by NASA and is being increasingly used in rock art research. It was used to digitally enhance symbols that are no longer visible to the naked eye.
Using portable X-ray fluorescence (PXRF) spectroscopy, the basic chemical composition of the pigment used in the motifs was also determined, and this gave the researchers data which revealed that different batches of paint had been used for some of the motifs. This suggests at least two separate episodes of producing the rock painting.
"Elk-head boats are often associated with hunting and fishing scenes, and we have interpreted the motifs in Tumlehed as three elk-head boats related to a small whale, a seal and four fish," says Bettina Schulz Paulsson.
The Tumlehed rock painting indicates similar maritime voyages during the Stone Age that are culturally connected to the peoples of eastern and northern Fennoscandia, an area that covers Norway, Sweden, Finland, the Kola Peninsula and Russian Karelia.
Bettina Schulz Paulsson et al.
Elk Heads at Sea: Maritime Hunters and Long‐Distance Boat Journeys in Late Stone Age Fennoscandia,
Oxford Journal of Archaeology (2019)