The Great London [Search results for Early Humans

  • Breaking News: Neanderthals killed off by diseases from modern humans, claims study

    Breaking News: Neanderthals killed off by diseases from modern humans, claims study

    Modern humans have been blamed for killing off the Neanderthals by out competing them, breeding with them and even outright murdering them.

    Neanderthals killed off by diseases from modern humans, claims study
    Neanderthals may have succumbed to infectious diseases carried to Europe by 
    modern humans as they migrated out of Africa [Credit: George Gillard]

    But new research suggests it may actually have been infectious diseases carried by our modern ancestors as they migrated out of Africa that finished them off.

    Scientists studying the latest genetic, fossil and archaeological evidence claim that Neanderthals suffered from a wide range of diseases that still plague us today.

    They have found evidence that suggests our prehistoric cousins would have been infected by diseases such as tuberculosis, typhoid, whooping cough, encephalitis and the common cold.

    But anthropologists from Cambridge University and Oxford Brookes University say that new diseases carried by modern humans may have led to the downfall of Neanderthals.

    They speculate that pathogens like Heliocbacter pylori, the bacteria that causes stomach ulcers, were brought to Europe by modern humans from Africa and may have infected Neanderthals, who would have been unable to fight off these new diseases.

    However, Neandethals may have also helped modern humans by passing on slivers of immunity against some diseases to our ancestors when they interbred.

    Dr Simon Underdown, a principal lecturer in anthropology at Oxford Brookes University and co-author of the study, said: 'As Neanderthal populations became more isolated they developed very small gene pools and this would have impacted their ability to fight off disease.

    'When Homo sapiens came out of Africa they brought diseases with them.

    'We know that Neanderthals were actually much more advanced than they have been given credit for and we even interbred with them.

    'Perhaps the only difference was that we were able to cope with these diseases but Neanderthals could not.'

    The findings add to a growing body of evidence that Neanderthals were not as different from modern humans as was originally thought.

    Recent discoveries have suggested that rather than being brutish cavemen, Neanderthals had sophisticated culture, were master tool makers and may even have had their own language.

    The new study suggests that Neanderthals also suffered from many of the same afflictions and complaints that modern humans experience.

    Indeed, there is some evidence from caves that early humans may have burned their bedding in a bid to rid themselves of infestations of lice or bed bugs.

    Dr Underdown and his colleague Dr Charlotte Houldcroft, a researcher in infectious diseases at Cambridge University and University College London, analysed recent genetic studies on Neanderthals and other early humans.

    They also examined recent genetic research on common human pathogens that have aimed to trace their origins and combined it with fossil and archaeological evidence.

    Most evidence from the fossil record suggest that Neanderthals tended to suffer traumatic injuries as a result of their hunter gatherer lifestyle, but there are also signs of inflammation and infection.

    Their study, which is published on the open source database bioRxiv, contradicts the common view that infectious diseases only really became a problem for humans in the Holocene about 11,000 years ago when humans began living in dense settlements and farming livestock.

    Instead, they say many of the diseases we see around us today were common during the pleistocene when Neanderthals dominated much of Europe and Asia between 250,000 and 45,000 years ago, when they disappeared.

    They say pathogens like TB, typhoid and Crimean fever that were thought to be zoonoses caught from herd animals may have actually originated in humans and were only passed to animals during the rise of farming around 8,000 years ago.

    Genetic sequencing of Neanderthal and Denisovan - another early human ancestor - DNA has shown that modern humans have inherited a number of genes from these extinct species.

    These include genes that provide immunity to viral infections such as tick-borne encephalitis.

    Dr Underdown said this virus would probably have been common in the forested areas of northern Europe that Neanderthals inhabited and so immunity would have been an advantage.

    Other genes found in modern Papua New Guineans that are involved in the immune response against viruses like dengue and influenza may have come from Neanderthals.

    Analysis of ancient DNA has also shown that Neanderthals carried genes that would have protected them against bacterial blood poisoning, or sepsis.

    Dr Underdown said: 'There are genetic signals in the Neanderthal genome that suggest quite clearly that they were exposed to these types of diseases but also developed some resistance to them.

    'It had been thought that many of these diseases began infecting humans with the population increases that came with domestication of animals and permanent settlements.

    'Be here we have got Neanderthals being infected by these diseases long before those developments.'

    Author: Richard Gray | Source: Daily Mail Online [April 03, 2015]

  • Early Humans: Modern humans out of Africa sooner than thought

    Early Humans: Modern humans out of Africa sooner than thought

    Human teeth discovered in southern China provide evidence that our species left the African continent up to 70,000 years earlier than prevailing theories suggest, a study published on Wednesday said.

    Modern humans out of Africa sooner than thought
    47 human teeth found in the Fuyan Cave, Daoxian, in southern China 
    [Credit: AFP/S. Xing and X-J. Wu]

    Homo sapiens reached present-day China 80,000-120,000 years ago, according to the study, which could redraw the migration map for modern humans.

    "The model that is generally accepted is that modern humans left Africa only 50,000 years ago," said Maria Martinon-Torres, a researcher at University College London and a co-author of the study.

    "In this case, we are saying the H. sapiens is out of Africa much earlier," she told the peer-reviewed journal Nature, which published the study.

    While the route they travelled remains unknown, previous research suggests the most likely path out of East Africa to east Asia was across the Arabian Peninsula and the Middle East.

    The findings also mean that the first truly modern humans -- thought to have emerged in east Africa some 200,000 years ago -- landed in China well before they went to Europe.

    There is no evidence to suggest that H. sapiens entered the European continent earlier than 45,000 years ago, at least 40,000 years after they showed up in present-day China.

    The 47 teeth exhumed from a knee-deep layer of grey, sandy clay inside the Fuyan Cave near the town of Daoxian closely resemble the dental gear of "contemporary humans," according to the study.

    They could only have come from a population that migrated from Africa, rather than one that evolved from an another species of early man such as the extinct Homo erectus, the authors said.

    The scientists also unearthed the remains of some 38 mammals, including specimens of five extinct species, one of them a giant panda larger than those in existence today.

    Modern humans out of Africa sooner than thought
    The location and interior views of the Fuyan Cave, with dating sample (lower left), 
    plan view of the excavation area with stratigraphy layer marked (C) 
    and the spatial relationship of the excavated regions 
    [Credit: AFP/Y-J Cai, X-X Yang, and X-J Wu]

    No tools were found.

    "Judging by the cave environment, it may not have been a living place for humans," lead author Wu Liu from the Chinese Academy of Science in Beijing told AFP.

    The study, published in the journal Nature, also rewrites the timeline of early man in China.

    Up to now, the earliest proof of H. sapiens east of the Arabian Peninsula came from the Tianyuan Cave near Beijing, and dated from no more than 40,000 years ago.

    The new discovery raises questions about why it took so long for H. sapiens to find their way to nearby Europe.

    "Why is it that modern humans -- who were already at the gates -- didn't really get into Europe?", Martinon-Torres asked.

    Wu and colleagues propose two explanations.

    The first is the intimidating presence of Neanderthal man. While this species of early human eventually died out, they were spread across the European continent up until at least some 50,000 years ago.

    "The classic idea is that H. sapiens... took over the Neanderthal empire, but maybe Neanderthals were a kind of ecological barrier, and Europe was too small a place" for both, Martinon-Torres said.

    Modern humans out of Africa sooner than thought
    Human upper teeth found in the Fuyan Cave, Daoxian, 
    in southern China [Credit: AFP/S. Xing and X-J. Wu]

    Another impediment might have been the cold.

    Up until the Ice Age ended 12,000 years ago, ice sheets stretched across a good part of the European continent, a forbidding environment for a new species emerging from the relative warmth of East Africa.

    "H. sapiens originated in or near the tropics, so it makes sense that the species' initial dispersal was eastwards rather than northwards, where winter temperatures rapidly fell below freezing," Robin Dennell of the University of Exeter said in a commentary, also in Nature.

    Martinon-Torres laid out some of the questions to be addressed in future research, using both genetics and fossil records.

    "What are the origins of these populations, and what was their fate? Did they vanish? Could they be the ancestors of later and current populations that entered Europe?"

    She also suggested there might have been "different movements and migrations" out of Africa, not just one.

    Besides the prehistoric panda, called Ailuropoda baconi, the scientists found an extinct species of a giant spotted hyaena.

    An elephant-like creature called Stegodon orientalis and a giant tapir, also present, were species that may have survived into the era when the Chinese had developed writing, some 3500 years ago.

    The cache of teeth nearly went unnoticed, Wu told AFP.

    He and his Chinese colleagues discovered the cave -- and its menagerie of long-deceased animals -- in the 1980s, but had no inkling that it also contained human remains.

    But 25 years later, while revisiting the site, Wu had a hunch.

    "By thinking about the cave environment, we realised that human fossils might be found there," he told AFP by email. "So we started a five-year excavation."

    Author: Marlowe Hood | Source: AFP [October 14, 2015]

  • Human Evolution: DNA from Neanderthal relative may shake up human family tree

    Human Evolution: DNA from Neanderthal relative may shake up human family tree

    In a remarkable technical feat, researchers have sequenced DNA from fossils in Spain that are about 300,000 to 400,000 years old and have found an ancestor—or close relative—of Neanderthals. The nuclear DNA, which is the oldest ever sequenced from a member of the human family, may push back the date for the origins of the distinct ancestors of Neanderthals and modern humans, according to a presentation here yesterday at the fifth annual meeting of the European Society for the study of human evolution.

    DNA from Neanderthal relative may shake up human family tree
    DNA from these fossilized bones and teeth in a Spanish cave are providing
     clues about the origins of Neanderthals and modern humans 
    [Credit: J.-J. Hublin; Royal Museum For Central Africa,
     Tervuren, Belgium]

    Ever since researchers first discovered thousands of bones and teeth from 28 individuals in the mid-1990s from Sima de los Huesos (“pit of bones”), a cave in the Atapuerca Mountains of Spain, they had noted that the fossils looked a lot like primitive Neanderthals. The Sima people, who lived before Neanderthals, were thought to have emerged in Europe. Yet their teeth, jaws, and large nasal cavities were among the traits that closely resembled those of Neanderthals, according to a team led by paleontologist Juan-Luis Arsuaga of the Complutense University of Madrid. As a result, his team classified the fossils as members of Homo heidelbergensis, a species that lived about 600,000 to 250,000 years ago in Europe, Africa, and Asia. Many researchers have thought H. heidelbergensis gave rise to Neanderthals and perhaps also to our species, H. sapiens, in the past 400,000 years or so.

    But in 2013, the Sima fossils’ identity suddenly became complicated when a study of the maternally inherited mitochondrial DNA (mtDNA) from one of the bones revealed that it did not resemble that of a Neanderthal. Instead, it more closely matched the mtDNA of a Denisovan, an elusive type of extinct human discovered when its DNA was sequenced from a finger bone from Denisova Cave in Siberia. That finding was puzzling, prompting researchers to speculate that perhaps the Sima fossils had interbred with very early Denisovans or that the “Denisovan” mtDNA was the signature of an even more ancient hominin lineage, such as H. erectus. At the time, researchers at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who had obtained the mtDNA announced that they would try to sequence the nuclear DNA of the fossils to solve the mystery.

    After 2 years of intense effort, paleogeneticist Matthias Meyer of the Max Planck Institute for Evolutionary Anthropology has finally sequenced enough nuclear DNA from fossils of a tooth and a leg bone from the pit to solve the mystery. The task was especially challenging because the ancient DNA was degraded to short fragments, made up of as few as 25 to 40 single nucleotides. (Nucleotides—also known as base pairs—are the building blocks of DNA.) Although he and his colleagues did not sequence the entire genomes of the fossils, Meyer reported at the meeting that they did get 1 million to 2 million base pairs of ancient nuclear DNA.

    DNA from Neanderthal relative may shake up human family tree
    Researchers have spent decades studying the remains found in the 'Pit of Bones', 
    reconstructing the skull shown above, which revealed it had suffered a 
    heavy blow to the head before death [Credit: msf]

    They scanned this DNA for unique markers found only in Neanderthals or Denisovans or modern humans, and found that the two Sima fossils shared far more alleles—different nucleotides at the same address in the genome—with Neanderthals than Denisovans or modern humans. “Indeed, the Sima de los Huesos specimens are early Neanderthals or related to early Neanderthals,” suggesting that the split of Denisovans and Neanderthals should be moved back in time, Meyer reported at the meeting.

    Researchers at the meeting were impressed by this new breakthrough in ancient DNA research. “This has been the next frontier with ancient DNA,” says evolutionary biologist Greger Larson of the University of Oxford in the United Kingdom.

    The close affinity with Neanderthals, but not with Denisovans or modern humans, suggests that the lineage leading to Neanderthals was separate from other archaic humans earlier than most researchers have thought. That means that the ancestors of modern humans also had to split earlier than expected from the population that gave rise to Neanderthals and Denisovans, who were more closely related to each other than they were to modern humans. (Although all three groups interbred at low levels after their evolutionary paths diverged—and such interbreeding may have been the source of the Denisovan mtDNA in the first Sima fossil whose DNA was sequenced.) Indeed, Meyer suggested in his talk that the ancestors of H. sapiens may have diverged from the branch leading to Neanderthals and Denisovans as early as 550,000 to 765,000 years ago, although those results depend on different mutation rates in humans and are still unpublished.

    That would mean that the ancestors of humans were already wandering down a solitary path apart from the other kinds of archaic humans on the planet 100,000 to 400,000 years earlier than expected. “It resolves one controversy—that they’re in the Neanderthal clade,” says paleoanthropologist Chris Stringer of the Natural History Museum in London. “But it’s not all good news: From my point of view, it pushes back the origin of H. sapiens from the Neanderthals and Denisovans.” The possibility that humans were a distinct group so early shakes up the human family tree, promising to lead to new debate about when and where the branches belong.

    Author: Ann Gibbons | Source: ScienceMag/AAAS [September 11, 2015]

  • East Asia: How China is rewriting the book on human origins

    East Asia: How China is rewriting the book on human origins

    On the outskirts of Beijing, a small limestone mountain named Dragon Bone Hill rises above the surrounding sprawl. Along the northern side, a path leads up to some fenced-off caves that draw 150,000 visitors each year, from schoolchildren to grey-haired pensioners. It was here, in 1929, that researchers discovered a nearly complete ancient skull that they determined was roughly half a million years old. Dubbed Peking Man, it was among the earliest human remains ever uncovered, and it helped to convince many researchers that humanity first evolved in Asia.

    How China is rewriting the book on human origins
    The reconstructed skull of Peking Man, the fossil that launched discussions 
    of human origins in China [Credit: DeAgostini/Getty]

    Since then, the central importance of Peking Man has faded. Although modern dating methods put the fossil even earlier—at up to 780,000 years old—the specimen has been eclipsed by discoveries in Africa that have yielded much older remains of ancient human relatives. Such finds have cemented Africa's status as the cradle of humanity—the place from which modern humans and their predecessors spread around the globe—and relegated Asia to a kind of evolutionary cul-de-sac.

    But the tale of Peking Man has haunted generations of Chinese researchers, who have struggled to understand its relationship to modern humans. "It's a story without an ending," says Wu Xinzhi, a palaeontologist at the Chinese Academy of Sciences' Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) in Beijing. They wonder whether the descendants of Peking Man and fellow members of the species Homo erectus died out or evolved into a more modern species, and whether they contributed to the gene pool of China today.

    Keen to get to the bottom of its people's ancestry, China has in the past decade stepped up its efforts to uncover evidence of early humans across the country. It is reanalysing old fossil finds and pouring tens of millions of dollars a year into excavations. And the government is setting up a US$1.1-million laboratory at the IVPP to extract and sequence ancient DNA.

    The investment comes at a time when palaeoanthropologists across the globe are starting to pay more attention to Asian fossils and how they relate to other early hominins—creatures that are more closely related to humans than to chimps. Finds in China and other parts of Asia have made it clear that a dazzling variety of Homo species once roamed the continent. And they are challenging conventional ideas about the evolutionary history of humanity.

    "Many Western scientists tend to see Asian fossils and artefacts through the prism of what was happening in Africa and Europe," says Wu. Those other continents have historically drawn more attention in studies of human evolution because of the antiquity of fossil finds there, and because they are closer to major palaeoanthropology research institutions, he says. "But it's increasingly clear that many Asian materials cannot fit into the traditional narrative of human evolution."

    Chris Stringer, a palaeoanthropologist at the Natural History Museum in London, agrees. "Asia has been a forgotten continent," he says. "Its role in human evolution may have been largely under-appreciated."

    Evolving story

    In its typical form, the story of Homo sapiens starts in Africa. The exact details vary from one telling to another, but the key characters and events generally remain the same. And the title is always 'Out of Africa'.

    How China is rewriting the book on human origins

    In this standard view of human evolution, H. erectus first evolved there more than 2 million years ago. Then, some time before 600,000 years ago, it gave rise to a new species: Homo heidelbergensis, the oldest remains of which have been found in Ethiopia. About 400,000 years ago, some members of H. heidelbergensis left Africa and split into two branches: one ventured into the Middle East and Europe, where it evolved into Neanderthals; the other went east, where members became Denisovans—a group first discovered in Siberia in 2010. The remaining population of H. heidelbergensis in Africa eventually evolved into our own species, H. sapiens, about 200,000 years ago. Then these early humans expanded their range to Eurasia 60,000 years ago, where they replaced local hominins with a minuscule amount of interbreeding.

    A hallmark of H. heidelbergensis—the potential common ancestor of Neanderthals, Denisovans and modern humans—is that individuals have a mixture of primitive and modern features. Like more archaic lineages, H. heidelbergensis has a massive brow ridge and no chin. But it also resembles H. sapiens, with its smaller teeth and bigger braincase. Most researchers have viewed H. heidelbergensis—or something similar—as a transitional form between H. erectus and H. sapiens.

    Unfortunately, fossil evidence from this period, the dawn of the human race, is scarce and often ambiguous. It is the least understood episode in human evolution, says Russell Ciochon, a palaeoanthropologist at the University of Iowa in Iowa City. "But it's central to our understanding of humanity's ultimate origin."

    The tale is further muddled by Chinese fossils analysed over the past four decades, which cast doubt over the linear progression from African H. erectus to modern humans. They show that, between roughly 900,000 and 125,000 years ago, east Asia was teeming with hominins endowed with features that would place them somewhere between H. erectus and H. sapiens, says Wu.

    "Those fossils are a big mystery," says Ciochon. "They clearly represent more advanced species than H. erectus, but nobody knows what they are because they don't seem to fit into any categories we know."

    How China is rewriting the book on human origins

    The fossils' transitional characteristics have prompted researchers such as Stringer to lump them with H. heidelbergensis. Because the oldest of these forms, two skulls uncovered in Yunxian in Hubei province, date back 900,000 years >1, 2>, Stringer even suggests that H. heidelbergensis might have originated in Asia and then spread to other continents.

    But many researchers, including most Chinese palaeontologists, contend that the materials from China are different from European and African H. heidelbergensis fossils, despite some apparent similarities. One nearly complete skull unearthed at Dali in Shaanxi province and dated to 250,000 years ago, has a bigger braincase, a shorter face and a lower cheekbone than most H. heidelbergensis specimens>3, suggesting that the species was more advanced.

    Such transitional forms persisted for hundreds of thousands of years in China, until species appeared with such modern traits that some researchers have classified them as H. sapiens. One of the most recent of these is represented by two teeth and a lower jawbone, dating to about 100,000 years ago, unearthed in 2007 by IVPP palaeoanthropologist Liu Wu and his colleagues>4. Discovered in Zhirendong, a cave in Guangxi province, the jaw has a classic modern-human appearance, but retains some archaic features of Peking Man, such as a more robust build and a less-protruding chin.

    Most Chinese palaeontologists—and a few ardent supporters from the West—think that the transitional fossils are evidence that Peking Man was an ancestor of modern Asian people. In this model, known as multiregionalism or continuity with hybridization, hominins descended from H. erectus in Asia interbred with incoming groups from Africa and other parts of Eurasia, and their progeny gave rise to the ancestors of modern east Asians, says Wu.

    Support for this idea also comes from artefacts in China. In Europe and Africa, stone tools changed markedly over time, but hominins in China used the same type of simple stone instruments from about 1.7 million years ago to 10,000 years ago. According to Gao Xing, an archaeologist at the IVPP, this suggests that local hominins evolved continuously, with little influence from outside populations.

    Politics at play?

    Some Western researchers suggest that there is a hint of nationalism in Chinese palaeontologists' support for continuity. "The Chinese—they do not accept the idea that H. sapiens evolved in Africa," says one researcher. "They want everything to come from China."

    Chinese researchers reject such allegations. "This has nothing to do with nationalism," says Wu. It's all about the evidence—the transitional fossils and archaeological artefacts, he says. "Everything points to continuous evolution in China from H. erectus to modern human."

    But the continuity-with-hybridization model is countered by overwhelming genetic data that point to Africa as the wellspring of modern humans. Studies of Chinese populations show that 97.4% of their genetic make-up is from ancestral modern humans from Africa, with the rest coming from extinct forms such as Neanderthals and Denisovans>5. "If there had been significant contributions from Chinese H. erectus, they would show up in the genetic data," says Li Hui, a population geneticist at Fudan University in Shanghai. Wu counters that the genetic contribution from archaic hominins in China could have been missed because no DNA has yet been recovered from them.

    Many researchers say that there are ways to explain the existing Asian fossils without resorting to continuity with hybridization. The Zhirendong hominins, for instance, could represent an exodus of early modern humans from Africa between 120,000 and 80,000 years ago. Instead of remaining in the Levant in the Middle East, as was thought previously, these people could have expanded into east Asia, says Michael Petraglia, an archaeologist at the University of Oxford, UK.

    How China is rewriting the book on human origins
    Dozens of teeth from a cave in Daoxian, China, have been attributed to modern humans 
    and date to 120,000–80,000 years ago [Credit: S. Xing and X-J. Wu]

    Other evidence backs up this hypothesis: excavations at a cave in Daoxian in China's Hunan province have yielded 47 fossil teeth so modern-looking that they could have come from the mouths of people today. But the fossils are at least 80,000 years old, and perhaps 120,000 years old, Liu and his colleagues reported last year>6. "Those early migrants may have interbred with archaic populations along the way or in Asia, which could explain Zhirendong people's primitive traits," says Petraglia.

    Another possibility is that some of the Chinese fossils, including the Dali skull, represent the mysterious Denisovans, a species identified from Siberian fossils that are more than 40,000 years old. Palaeontologists don't know what the Denisovans looked like, but studies of DNA recovered from their teeth and bones indicate that this ancient population contributed to the genomes of modern humans, especially Australian Aborigines, Papua New Guineans and Polynesians—suggesting that Denisovans might have roamed Asia.

    Maria Martinon-Torres, a palaeoanthropologist at University College London, is among those who proposed that some of the Chinese hominins were Denisovans. She worked with IVPP researchers on an analysis>7, published last year, of a fossil assemblage uncovered at Xujiayao in Hebei province—including partial jaws and nine teeth dated to 125,000–100,000 years ago. The molar teeth are massive, with very robust roots and complex grooves, reminiscent of those from Denisovans, she says.

    A third idea is even more radical. It emerged when Martinon-Torres and her colleagues compared more than 5,000 fossil teeth from around the world: the team found that Eurasian specimens are more similar to each other than to African ones>8. That work and more recent interpretations of fossil skulls suggest that Eurasian hominins evolved separately from African ones for a long stretch of time. The researchers propose that the first hominins that left Africa 1.8 million years ago were the eventual source of modern humans. Their descendants mostly settled in the Middle East, where the climate was favourable, and then produced waves of transitional hominins that spread elsewhere. One Eurasian group went to Indonesia, another gave rise to Neanderthals and Denisovans, and a third ventured back into Africa and evolved into H. sapiens, which later spread throughout the world. In this model, modern humans evolved in Africa, but their immediate ancestor originated in the Middle East.

    Not everybody is convinced. "Fossil interpretations are notoriously problematic," says Svante Paabo, a palaeogeneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. But DNA from Eurasian fossils dating to the start of the human race could help to reveal which story—or combination—is correct. China is now making a push in that direction. Qiaomei Fu, a palaeogeneticist who did her PhD with Paabo, returned home last year to establish a lab to extract and sequence ancient DNA at the IVPP. One of her immediate goals is to see whether some of the Chinese fossils belong to the mysterious Denisovan group. The prominent molar teeth from Xujiayao will be an early target. "I think we have a prime suspect here," she says.

    Fuzzy picture

    Despite the different interpretations of the Chinese fossil record, everybody agrees that the evolutionary tale in Asia is much more interesting than people appreciated before. But the details remain fuzzy, because so few researchers have excavated in Asia.

    When they have, the results have been startling. In 2003, a dig on Flores island in Indonesia turned up a diminutive hominin>9, which researchers named Homo floresiensis and dubbed the hobbit. With its odd assortment of features, the creature still provokes debate about whether it is a dwarfed form of H. erectus or some more primitive lineage that made it all the way from Africa to southeast Asia and lived until as recently as 60,000 years ago. Last month, more surprises emerged from Flores, where researchers found the remains of a hobbit-like hominin in rocks about 700,000 years old>10.

    Recovering more fossils from all parts of Asia will clearly help to fill in the gaps. Many palaeoanthropologists also call for better access to existing materials. Most Chinese fossils—including some of the finest specimens, such as the Yunxian and Dali skulls—are accessible only to a handful of Chinese palaeontologists and their collaborators. "To make them available for general studies, with replicas or CT scans, would be fantastic," says Stringer. Moreover, fossil sites should be dated much more rigorously, preferably by multiple methods, researchers say.

    But all agree that Asia—the largest continent on Earth—has a lot more to offer in terms of unravelling the human story. "The centre of gravity," says Petraglia, "is shifting eastward."

    Author: Jane Qiu | Source: Nature 535, 22–25 (14 July 2016) doi:10.1038/535218a [July 15, 2016]

  • Human Evolution: Monkeys are seen making stone flakes so humans are 'not unique' after all

    Human Evolution: Monkeys are seen making stone flakes so humans are 'not unique' after all

    Researchers have observed wild-bearded capuchin monkeys in Brazil deliberately break stones, unintentionally creating flakes that share many of the characteristics of those produced by early Stone Age hominins. The difference is that the capuchins' flakes are not intentional tools for cutting and scraping, but seem to be the by-product of hammering or 'percussive behaviour' that the monkeys engage in to extract minerals or lichen from the stones.

    Monkeys are seen making stone flakes so humans are 'not unique' after all
    Wild-bearded capuchin monkey in Serra da Capivara National Park, Brazil, unintentionally creating
     fractured flakes and cores [Credit: Michael Haslam/ Primate Archaeology Group]

    In a paper, >published in Nature, the research team says this finding is significant because archaeologists had always understood that the production of multiple stone flakes with characteristics such as conchoidal fractures and sharp cutting edges was a behaviour unique to hominins. The paper suggests that scholars may have to refine their criteria for identifying intentionally produced early stone flakes made by hominins, given capuchins have been observed unintentionally making similar tools.

    The research is authored by researchers from the University of Oxford, University College London and University of Sao Paulo in Brazil. The team observed individual monkeys in Serra da Capivara National Park unintentionally creating fractured flakes and cores. While hominins made stone flake tools for cutting and butchery tasks, the researchers admit that it is unclear why monkeys perform this behaviour. They suggest that the capuchins may be trying to extract powdered silicon (known to be an essential trace nutrient) or to remove lichen for some as yet unknown medicinal purpose. At no point did the monkeys try to cut or scrape using the flakes, says the study.

    Lead author Dr Tomos Proffitt, from the School of Archaeology at the University of Oxford, comments: 'Within the last decade, studies have shown that the use and intentional production of sharp-edged flakes are not necessarily linked to early humans (the genus Homo) who are our direct relatives, but instead were used and produced by a wider range of hominins. However, this study goes one step further in showing that modern primates can produce archaeologically identifiable flakes and cores with features that we thought were unique to hominins.


    'This does not mean that the earliest archaeological material in East Africa was not made by hominins. It does, however, raise interesting questions about the possible ways this stone tool technology developed before the earliest examples in the archaeological record appeared. It also tells us what this stone tool technology might look like. There are important questions too about the uniqueness of early hominin behaviour. These findings challenge previous ideas about the minimum level of cognitive and morphological complexity required to produce numerous conchoidal flakes.'

    The monkeys were observed engaging in 'stone on stone percussion', whereby they individually selected rounded quartzite cobbles and then using one or two hands struck the 'hammer-stone' forcefully and repeatedly on quartzite cobbles embedded in a cliff face. This action crushed the surface and dislodged cobbled stones, and the hand-held 'hammer stones' became unintentionally fractured, leaving an identifiable primate archaeological record. As well as using the active hammer-stone to crush 'passive hammers' (stones embedded in the outcrop), the capuchins were also observed re-using broken hammer-stones as 'fresh' hammers.

    The research team examined 111 fragmented stones collected from the ground immediately after the capuchins had dropped them, as well as from the surface and excavated areas in the site. They gathered complete and broken hammer-stones, complete and fragmented flakes and passive hammers. Around half of the fractured flakes exhibited conchoidal fracture, which is typically associated with the hominin production of flakes.

    Bearded capuchins and some Japanese macaques are known to pound stones directly against each other, but the paper remarks that the capuchins in Serra da Capivara National Park are the only wild primates to be observed doing this for the purpose of damaging the stones.

    Co-author and leader of the Primate Archaeology (Primarch) project Michael Haslam, from the University of Oxford, says: 'Our understanding of the new technologies adopted by our early ancestors helps shape our view of human evolution. The emergence of sharp-edged stone tools that were fashioned and hammered to create a cutting tool was a big part of that story. The fact that we have discovered monkeys can produce the same result does throw a bit of a spanner in the works in our thinking on evolutionary behaviour and how we attribute such artefacts. While humans are not unique in making this technology, the manner in which they used them is still very different to what the monkeys seem capable of.'

    Source: University of Oxford [October 19, 2016]

  • Genetics: A federal origin of Stone Age farming

    Genetics: A federal origin of Stone Age farming

    The transition from hunter-gatherer to sedentary farming 10,000 years ago occurred in multiple neighbouring but genetically distinct populations according to research by an international team including UCL.

    A federal origin of Stone Age farming
    The Fertile Crescent (shaded) on a political map of the Near and South East. In blue are the the archaeological sites
     in Iran with genomes from the Neolithic period that are ancestral to modern-day South Asians. In red are Neolithic
     sites with genomes that are ancestral to all European early farmers [Credit: ©: Joachim Burger, JGU]

    “It had been widely assumed that these first farmers were from a single, genetically homogeneous population. However, we’ve found that there were deep genetic differences in these early farming populations, indicating very distinct ancestries,” said corresponding author Dr Garrett Hellenthal, UCL Genetics.

    The study, published today in >Science and funded by Wellcome and Royal Society, examined ancient DNA from some of the world’s first farmers from the Zagros region of Iran and found it to be very different from the genomes of early farmers from the Aegean and Europe. The team identified similarities between the Neolithic farmer’s DNA and that of living people from southern Asia, including from Afghanistan, Pakistan, Iran, and Iranian Zoroastrians in particular.

    “We know that farming technologies, including various domestic plants and animals, arose across the Fertile Crescent, with no particular centre” added co-author Professor Mark Thomas, UCL Genetics, Evolution & Environment.

    “But to find that this region was made up of highly genetically distinct farming populations was something of a surprise. We estimated that they separated some 46 to 77,000 years ago, so they would almost certainly have looked different, and spoken different languages. It seems like we should be talking of a federal origin of farming.”

    A federal origin of Stone Age farming
    An approximately 10,000 year old skull from the Neolithic Tepe Abdul Hossein 
    [Credit: © Fereidoun Biglari, National Museum of Iran]

    The switch from mobile hunting and gathering to sedentary farming first occurred around 10,000 years ago in south-western Asia and was one of the most important behavioural transitions since humans first evolved in Africa some 200,000 years ago. It led to profound changes in society, including greater population densities, new diseases, poorer health, social inequality, urban living, and ultimately, the rise of ancient civilizations.

    Animals and plants were first domesticated across a region stretching north from modern-day Israel, Palestine and Lebanon to Syria and eastern Turkey, then east into, northern Iraq and north-western Iran, and south into Mesopotamia; a region known as the Fertile Crescent.

    “Such was the impact of farming on our species that archaeologists have debated for more than 100 years how it originated and how it was spread into neighbouring regions such as Europe, North Africa and southern Asia,” said co-author Professor Stephen Shennan, UCL Institute of Archaeology.

    “We’ve shown for the first time that different populations in different parts of the Fertile Crescent were coming up with similar solutions to finding a successful way of life in the new conditions created by the end of the last Ice Age.”

    A federal origin of Stone Age farming
    Analysis of ancient DNA in the laboratory [Credit: ©: JGU Palaeogenetics Group]

    By looking at how ancient and living people share long sections of DNA, the team showed that early farming populations were highly genetically structured, and that some of that structure was preserved as farming, and farmers, spread into neighbouring regions; Europe to the west and southern Asia to the east.

    “Early farmers from across Europe, and to some extent modern-day Europeans, can trace their DNA to early farmers living in the Aegean, whereas people living in Afghanistan, Pakistan, Iran and India share considerably more long chunks of DNA with early farmers in Iran. This genetic legacy of early farmers persists, although of course our genetic make-up subsequently has been reshaped by many millennia of other population movements and intermixing of various groups,” concluded Dr Hellenthal.

    Source: University College London [July 14, 2016]

  • Early Humans: Evidence of oat grinding by Stone Age hunter-gatherers found in Italy

    Early Humans: Evidence of oat grinding by Stone Age hunter-gatherers found in Italy

    Archaeologists have uncovered a stone grinding tool in southern Italy which shows signs it was used to make flour that was boiled into gruel or baked into bread.

    Evidence of oat grinding by Stone Age hunter-gatherers found in Italy
    Interior of Grotta Paglicci, Italy, with wall paintings 
    [Credit: Stefano Ricci]

    The discovery, which predates the dawn of farming, suggests that stone age man's first cultivated meal may have been a bowl of porridge made from grains growing wild and is the earliest known instance of human consumption of oats.

    The find was made by a team led by Marta Mariotti Lippi at the University of Florence in Italy who made analysed starch grains found on the artefact.

    They found evidence that the stone's creators also heated the grains before grinding them, perhaps to dry them out in the colder climate of the time and make the grain easier to grind and longer-lasting.

    This multi-stage process would have been time consuming, but beneficial, while turning it into flour would have been a good way to transport it, which was important for Palaeolithic nomads.

    Evidence of oat grinding by Stone Age hunter-gatherers found in Italy
    Grinding stone from Grotta Paglicci, Italy
    [Credit: Stefano Ricci]

    Evidence of porridge consumption in Scotland dates back to 4,000 BC, when oats and other grains began to be cultivated by the first farmers.

    Mariotti Lippi’s team hopes to continue studying ancient grinding stones to find out more about the stone age plant diet.

    The stone was found in the Grotta Paglicci, Apulia, which was home to stone age hunter gatherers between 34,000 and 32,000 years ago and contains mural paintings, depicting horses and handprints. Images of goats, cows, a serpent, a nest with eggs, and a hunting scene have also been found engraved on bone.

    Archaeologist Matt Pope, of University College London, said that the find shed light on the diet of early humans and the spread of food cultivation.

    Evidence of oat grinding by Stone Age hunter-gatherers found in Italy
    Swollen, gelatinized starch grain from the Paglicci grinding stone 
    [Credit: Marta Mariotti Lippi]

    He said: “There is a relationship there to be explored between diet, experimentation with processing plant food and cultural sophistication.

    “We’ve had evidence of the processing of roots and cattails, but here we’ve got a grain, and a grain that we’re very familiar with.

    “If we were to look more systematically for ground stone technology we would find this is a more widespread phenomenon.”

    The study is published in Proceedings of the National Academy of Sciences.

    Author: Jody Harrison | Source: Herald Scotland [September 08, 2015]

  • Natural Heritage: More infectious diseases emerging because of climate change

    Natural Heritage: More infectious diseases emerging because of climate change

    The appearance of infectious diseases in new places and new hosts, such as West Nile virus and Ebola, is a predictable result of climate change, says a noted zoologist affiliated with the Harold W. Manter Laboratory of Parasitology at the University of Nebraska-Lincoln.

    More infectious diseases emerging because of climate change
    In some areas of Costa Rica, howler monkeys like this one are infected with parasites 
    once limited to capuchin and spider monkeys. After humans hunted capuchins and 
    spider monkeys out of existence in the region, the parasites immediately switched to
    howler monkeys, where they persist today [Credit: Daniel Brooks Photography]

    In an article published online today in conjunction with a special issue of the Philosophical Transactions of the Royal Society B, Daniel Brooks warns that humans can expect more such illnesses to emerge in the future, as climate change shifts habitats and brings wildlife, crops, livestock, and humans into contact with pathogens to which they are susceptible but to which they have never been exposed before.

    "It's not that there's going to be one 'Andromeda Strain' that will wipe everybody out on the planet," Brooks said, referring to the 1971 science fiction film about a deadly pathogen. "There are going to be a lot of localized outbreaks putting pressure on medical and veterinary health systems. It will be the death of a thousand cuts."

    Brooks and his co-author, Eric Hoberg, a zoologist with the U.S. National Parasite Collection of the USDA's Agricultural Research Service, have personally observed how climate change has affected very different ecosystems. During his career, Brooks has focused primarily on parasites in the tropics, while Hoberg has worked primarily in Arctic regions.

    Each has observed the arrival of species that hadn't previously lived in that area and the departure of others, Brooks said.

    "Over the last 30 years, the places we've been working have been heavily impacted by climate change," Brooks said in an interview last week. "Even though I was in the tropics and he was in the Arctic, we could see something was happening." Changes in habitat mean animals are exposed to new parasites and pathogens.

    For example, Brooks said, after humans hunted capuchin and spider monkeys out of existence in some regions of Costa Rica, their parasites immediately switched to howler monkeys, where they persist today. Some lungworms in recent years have moved northward and shifted hosts from caribou to muskoxen in the Canadian Arctic.

    But for more than 100 years, scientists have assumed parasites don't quickly jump from one species to another because of the way parasites and hosts co-evolve.

    Brooks calls it the "parasite paradox." Over time, hosts and pathogens become more tightly adapted to one another. According to previous theories, this should make emerging diseases rare, because they have to wait for the right random mutation to occur.

    However, such jumps happen more quickly than anticipated. Even pathogens that are highly adapted to one host are able to shift to new ones under the right circumstances.

    Brooks and Hoberg call for a "fundamental conceptual shift" recognizing that pathogens retain ancestral genetic capabilities allowing them to acquire new hosts quickly.

    "Even though a parasite might have a very specialized relationship with one particular host in one particular place, there are other hosts that may be as susceptible," Brooks said.

    In fact, the new hosts are more susceptible to infection and get sicker from it, Brooks said, because they haven't yet developed resistance.

    Though resistance can evolve fairly rapidly, this only changes the emergent pathogen from an acute to a chronic disease problem, Brooks adds.

    "West Nile Virus is a good example - no longer an acute problem for humans or wildlife in North America, it nonetheless is hhere to stay," he said.

    The answer, Brooks said, is for greater collaboration between the public and veterinary health communities and the "museum" community - the biologists who study and classify life forms and how they evolve.

    In addition to treating human cases of an emerging disease and developing a vaccine for it, he said, scientists need to learn which non-human species carry the pathogen.

    Knowing the geographic distribution and the behavior of the non-human reservoirs of the pathogen could lead to public health strategies based on reducing risk of infection by minimizing human contact with infected animals, much likethose that reduced the incidence of malaria and yellow fever by reducing human contact with mosquitos.

    Museum scientists versed in understanding the evolutionary relationships among species could use this knowledge to anticipate the risk of the pathogen becoming established outside of its native range.

    Brooks, who earned his bachelor's and master's degrees from the University of Nebraska-Lincoln, was a zoology professor at the University of Toronto for 30 years until he retired early in 2011 to devote more time to his study of emerging infectious disease. In addition to being a senior research fellow with UNL's Manter Laboratory, he is a visiting senior fellow at the Universidade Federal do Parana, Brazil, funded by the Ciencias sem Fronteiras (Sciences without Borders) of the Brazilian government, and a visiting scholar with Debrecen University in Hungary.

    Brooks' and Hoberg's article, "Evolution in action: climate change, biodiversity dynamics and emerging infectious disease," is part of a Philosophical Transactions of the Royal Society B issue on "Climate change and vector-borne diseases of humans," edited by Paul Parham, a specialist in infectious disease epidemiology at Imperial College in London.

    "We have to admit we're not winning the war against emerging diseases," Brooks said. "We're not anticipating them. We're not paying attention to their basic biology, where they might come from and the potential for new pathogens to be introduced."

    Source: University of Nebraska-Lincoln [February 16, 2015]

  • Chanel Islands: Jersey was a must-see tourist destination for Neanderthals for over 100,000 years

    Chanel Islands: Jersey was a must-see tourist destination for Neanderthals for over 100,000 years

    New research led by the University of Southampton shows Neanderthals kept coming back to a coastal cave site in Jersey from at least 180,000 years ago until around 40,000 years ago.

    Jersey was a must-see tourist destination for Neanderthals for over 100,000 years
    Aerial photo of La Cotte de St Brelade [Credit: Dr Sarah Duffy]

    As part of a re-examination of La Cotte de St Brelade and its surrounding landscape, archaeologists from Southampton, together with experts from three other universities and the British Museum, have taken a fresh look at artefacts and mammoth bones originally excavated from within the site's granite cliffs in the 1970s. Their findings are published in the >journal Antiquity.

    The researchers matched types of stone raw material used to make tools to detailed mapping of the geology of the sea bed, and studied in detail how they were made, carried and modified. This helped reconstruct a picture of what resources were available to Neanderthals over tens of thousands of years -- and where they were travelling from.

    Lead author Dr Andy Shaw of the Centre for the Archaeology of Human Origins (CAHO) at the University of Southampton said: "La Cotte seems to have been a special place for Neanderthals. They kept making deliberate journeys to reach the site over many, many generations. We can use the stone tools they left behind to map how they were moving through landscapes, which are now beneath the English Channel. 180,000 years ago, as ice caps expanded and temperatures plummeted, they would have been exploiting a huge offshore area, inaccessible to us today."

    Previous research focussed on particular levels in the site where mammoth bones are concentrated, but this new study took a longer-term perspective, looking at how Neanderthals used it and explored the surrounding landscape for over 100,000 years.

    Jersey was a must-see tourist destination for Neanderthals for over 100,000 years
    Archaeologists at La Cotte de St Brelade [Credit: Dr Sarah Duffy]

    The team, including academics from the British Museum, University College London (UCL) and the University of Wales found that Neanderthals kept coming back to this particular place, despite globally significant changes in climate and landscape. During glacial phases (Ice Ages), they travelled to the site over cold, open landscapes, now submerged under the sea. They kept visiting as the climate warmed up and Jersey became a striking highpoint in a wide coastal plain connected to France.

    Dr Beccy Scott of the British Museum added: "We're really interested in how this site became 'persistent' in the minds of early Neanderthals. You can almost see hints of early mapping in the way they are travelling to it again and again, or certainly an understanding of their geography. But specifically what drew them to Jersey so often is harder to tease out. It might have been that the whole Island was highly visible from a long way off -- like a waymarker -- or people might have remembered that shelter could be found there, and passed that knowledge on."

    Paper author Dr Matt Pope, of the Institute of Archaeology at UCL, agrees: "La Cotte de St Brelade is probably the most important Neanderthal site in northern Europe and could be one of the last known places that Neanderthals survived in the region. It was certainly as important to them as it is to us, as we try and understand how they thrived and survived for 200,000 years.

    "With new technology we have been able to reconstruct the environment of the La Cotte Neanderthals in a way earlier researchers couldn't. Our project has really put the Neanderthal back into the landscape, but emphasised how significant the changes in climate and landscape have been since then."

    Project leader Professor Clive Gamble, of CAHO at the University of Southampton, comments: "Jersey is an island that endures, summed up by the granite cliffs of St Brelade's Bay. The elements which led to Neanderthals coming back for so many thousands of years shows how this persistence is deep rooted in Jersey's past. Our project has shown that more unites the past with the present than separates. We are not the only humans to have coped successfully with major environmental changes. Let's hope we are not the last."

    The team's work was undertaken as part of the 'Crossing the Threshold' project led by Professor Clive Gamble and Dr John McNabb at the University of Southampton, together with UCL and the British Museum. The research was funded by the Arts and Humanities Research Council and looks at major changes in how early humans used places from 400,000 years ago.

    Source: University of Southampton [December 12, 2016]

  • Recommended Reading: 'Map of Life' predicts ET, so where is he?

    Recommended Reading: 'Map of Life' predicts ET, so where is he?

    Extra-terrestrials that resemble humans should have evolved on other, Earth-like planets, making it increasingly paradoxical that we still appear to be alone in the universe, the author of a new study on convergent evolution has claimed.

    'Map of Life' predicts ET, so where is he?
    The camera eye of an octopus is structurally similar to that of a human, but has
     evolved independently, making it a classic example of convergent evolution 
    [Credit: albert kok/WikiCommons]

    The argument is one of several that emerge from The Runes Of Evolution, a new book in which the leading evolutionary biologist, Professor Simon Conway Morris, makes the case for a ubiquitous "map of life" that governs the way in which all living things develop.

    It builds on the established principle of convergent evolution, a widely-supported theory -- although one still disputed by some biologists -- that different species will independently evolve similar features.

    Conway Morris argues that convergence is not just common, but everywhere, and that it has governed every aspect of life's development on Earth. Proteins, eyes, limbs, intelligence, tool-making -- even our capacity to experience orgasms -- are, he argues, inevitable once life emerges.

    The book claims that evolution is therefore far from random, but a predictable process that operates according to a fairly rigid set of rules.

    If that is the case, then it follows that life similar to that on Earth would also develop in the right conditions on other, equivalent planets. Given the growing number of Earth-like planets of which astronomers are now aware, it is increasingly extraordinary that aliens that look and behave something like us have not been found, he suggests.

    "Convergence is one of the best arguments for Darwinian adaptation, but its sheer ubiquity has not been appreciated," Professor Conway Morris, who is a Fellow at St John's College, University of Cambridge, said.

    "Often, research into convergence is accompanied by exclamations of surprise, describing it as uncanny, remarkable and astonishing. In fact it is everywhere, and that is a remarkable indication that evolution is far from a random process. And if the outcomes of evolution are at least broadly predictable, then what applies on Earth will apply across the Milky Way, and beyond."

    Professor Conway Morris has previously raised the prospect that alien life, if out there, would resemble earthlings -- with limbs, heads, and bodies -- notably at a Royal Society Conference in London in 2010. His new book goes even further, however, adding that any Earth-like planet should also evolve thunniform predators (like sharks), pitcher plants, mangroves, and mushrooms, among many other things.

    Limbs, brains and intelligence would, similarly, be "almost guaranteed." The traits of human-like intelligence have evolved in other species -- the octopus and some birds, for example, both exhibit social playfulness -- and this, the book suggests, indicates that intelligence is an inevitable consequence of evolution that would characterise extraterrestrials as well.

    Click on image to view at Amazon
    Underpinning this is Conway Morris' claim that convergence is demonstrable at every major stepping stone in evolutionary history, from early cells, through to the emergence of tissues, sensory systems, limbs, and the ability to make and use tools.

    The theory, in essence, is that different species will evolve similar solutions to problems via different paths. A commonly-cited example is the octopus, which has evolved a camera eye that is closely similar to that of humans, although distinctive in important ways that reflect its own history. Although octopi and humans have a common ancestor, possibly a slug-like creature, this lived 550 million years ago and lacked numerous complex features that the two now share. The camera eye of each must therefore have evolved independently.

    Conway Morris argues that this process provides an underlying evolutionary framework that defines all life, and leads to innumerable surprises in the natural world. The book cites examples such as collagen, the protein found in connective tissue, which has emerged independently in both fungi and bacteria; or the fact that fruit flies seem to get drunk in the same manner as humans. So too the capacity for disgust in humans -- a hard-wired instinct helping us avoid infection and disease -- is also exhibited by leaf-cutter ants.

    The study also identifies many less obvious evolutionary "analogues," where species have evolved certain properties and characteristics that do not appear to be alike, but are actually very similar. For example, "woodpeckerlike habits" are seen in lemurs and extinct marsupials, while the mechanics of an octopus' tentacles are far closer to those of a human arm than we might expect, and even their suckers can operate rather like hands.

    Conway Morris contends that all life navigates across this evolutionary map, the basis of what he describes as a "predictive biology." "Biology travels through history," he writes, "but ends up at much the same destination."

    This, however, raises fascinating and problematic questions about the possibility of life occurring on other planets. "The number of Earth-like planets seems to be far greater than was thought possible even a few years ago," Conway Morris said. "That doesn't necessarily mean that they have life, because we don't necessarily understand how life originates. The consensus offered by convergence, however, is that life is going to evolve wherever it can."

    "I would argue that in any habitable zone that doesn't boil or freeze, intelligent life is going to emerge, because intelligence is convergent. One can say with reasonable confidence that the likelihood of something analogous to a human evolving is really pretty high. And given the number of potential planets that we now have good reason to think exist, even if the dice only come up the right way every one in 100 throws, that still leads to a very large number of intelligences scattered around, that are likely to be similar to us."

    If this is so, as the book suggests in its introduction, then it makes Enrico Fermi's famous paradox -- why, if aliens exist, we have not yet been contacted -- even more perplexing. "The almost-certainty of ET being out there means that something does not add up, and badly," Conway Morris said. "We should not be alone, but we are."

    The Runes Of Evolution was six years in the making and draws on thousands of academic sources, and throws up numerous other, surprising findings as well. Sabre-teeth, for example, turn out to be convergent, and Conway Morris explains why it is that the clouded leopard of Asia, Neofelis nebulosa, has developed features that could, as it evolves "presage the emergence of a new sabre-tooth," although sadly it looks set to become extinct before this happens. Elsewhere, the study suggests that certain prehistoric creatures other than bats and birds may have attempted to evolve flight.

    "It makes people slightly uneasy that evolution can end up reaching the same solutions to questions about how to catch something, how to digest something, and how to work," Conway Morris added. "But while the number of possibilities in evolution in principle is more than astronomical, the number that actually work is an infinitesimally smaller fraction."

    The Runes Of Evolution, by Simon Conway Morris, is published by Templeton Press

    Source: University of Cambridge [July 02, 2015]

  • UK: Human presence in Ireland pushed back by 2,500 years

    UK: Human presence in Ireland pushed back by 2,500 years

    A remarkable archaeological discovery in a Co. Clare cave has pushed back the date of human existence in Ireland by 2,500 years.

    Human presence in Ireland pushed back by 2,500 years
    Dr Marion Dowd of IT Sligo with the brown bear bone in the Institute’s 
    archaeology lab [Credit: James Connolly]

    This discovery re-writes Irish archaeology and adds an entirely new chapter to human colonisation of the island – moving Ireland’s story into a new era.

    Radiocarbon dating of a butchered brown bear bone, which has been stored in a cardboard box at the National Museum of Ireland for almost 100 years, has established that humans were on the island of Ireland some 12,500 years ago – 2,500 earlier than previously believed.

    Since the 1970s, the oldest evidence of human occupation on the island of Ireland has been at Mount Sandel in Co. Derry. This site has been dated at 8,000 BC, which is in the Mesolithic period, indicating that humans had occupied the island for some 10,000 years.

    However, new analysis of the bear patella – or knee bone – originally found in Co. Clare in 1903 gives us undisputed evidence that people existed in Ireland during the preceding Palaeolithic period at 10,500 BC, some 12,500 years ago.

    This is a major breakthrough for archaeologists who have spent decades searching for earlier signs of human occupation on the island.

    The discovery was made by Dr Marion Dowd, an archaeologist at IT Sligo, and Dr Ruth Carden, a Research Associate with the National Museum of Ireland.

    Human presence in Ireland pushed back by 2,500 years
    The patella, or knee bone, bears seven or eight marks on its surface that appear 
    to have been made with a stone knife [Credit: James Connolly]

    “Archaeologists have been searching for the Irish Palaeolithic since the 19th century, and now, finally, the first piece of the jigsaw has been revealed. This find adds a new chapter to the human history of Ireland,” said Dr Dowd.

    Dowd and Carden’s paper on the discovery was published in the journal Quaternary Science Reviews. Dr Dowd is a lecturer in Prehistoric Archaeology at the School of Science in IT Sligo and is a specialist in Irish cave archaeology.

    The adult bear bone was one of thousands of bones originally discovered in Alice and Gwendoline Cave, Co. Clare in 1903 by a team of early scientists. They published a report on their investigations and noted that the bear bone had knife marks.

    The bone was stored in a collection at the National Museum of Ireland since the 1920s. In 2010 and 2011, animal osteologist Dr Ruth Carden, a Research Associate at the museum, was re-analysing its animal bone collections from early cave excavations. She came across the bear bone and documented it along with many others.

    As a specialist in cave archaeology, Dr Dowd, became interested in the butchered bear patella and, together with Dr Carden, the pair sought funding from the Royal Irish Academy for radiocarbon dating, which was carried out by the Chrono Centre at Queen’s University Belfast.

    “When a Palaeolithic date was returned, it came as quite a shock. Here we had evidence of someone butchering a brown bear carcass and cutting through the knee probably to extract the tendons. Yes, we expected a prehistoric date, but the Palaeolithic result took us completely by surprise,” says Dr Dowd.

    Human presence in Ireland pushed back by 2,500 years
    Analysis of the bone suggested the cut marks were made while the bone was still fresh, 
    meaning it may have been killed and certainly butchered by some of the first 
    humans in Ireland after the last Ice Age [Credit: IT Sligo]

    A second sample was sent to the University of Oxford for radiocarbon dating to test the validity of the initial result. Both dates indicated human butchery of the bear about 12,500 years ago.

    The bone was then sent to three bone specialists for independent analysis of the cut marks. These were Dr Jill Cook at the British Museum in London; Prof. Terry O’Connor at the University of York and Prof. Alice Choyke at the Central European University in Hungary.

    The experts were unaware of the radiocarbon dating results prior to their examinations but all determined that the cut marks were made on fresh bone, confirming that the cut marks were of the same date as the patella, and therefore that humans were in Ireland during the Palaeolithic period.

    “This made sense as the location of the marks spoke of someone trying to cut through the tough knee joint, perhaps someone who was inexperienced,” explains Dr Dowd. “In their repeated attempts, they left seven marks on the bone surface. The implement used would probably have been something like a long flint blade.”

    “The bone was in fresh condition meaning that people were carrying out activities in the immediate vicinity – possibly butchering a bear inside the cave or at the cave entrance,” said Dr Dowd.

    Dr Ruth Carden said:  “From a zoological point of view, this is very exciting, since up to now we have not factored in a possible ‘human-dimension’ when we are studying patterns of colonisation and local extinctions of species to Ireland.

    “This paper should generate a lot of discussion within the zoological research world and it’s time to start thinking outside the box…or even dismantling it entirely!”


    Dr Dowd and Dr Carden are now hoping to get funding to carry out further analysis of other material recovered during the 1903 excavations, the cave itself and other potential cave sites around the country.

    Professor Vincent Cunnane, President of IT Sligo said: “Academic research is often lauded for helping to shape new concepts and innovations of the future, but this ground-breaking discovery for Irish archaeology highlights the vital role it can play in challenging and deepening our understanding of our heritage and history.”

    Nigel T. Monaghan, Keeper, Natural History Division of the National Museum of Ireland said: “The National Museum of Ireland – Natural History, holds collections of approximately two million specimens, all are available for research and we never know what may emerge. Radiocarbon dating is something never imagined by the people who excavated these bones in caves over a century ago, and these collections may have much more to reveal about Ireland’s ancient past.”

    The remarkable discovery comes just three years after the first evidence of Palaeolithic occupation of Scotland was uncovered. In 2013, a cache of flint tools was unearthed on the Isle of Islay, pushing the date of human existence in Scotland from the Mesolithic into the Palaeolithic era.

    Source: Institute of Technology Sligo [March 20, 2016]

  • Fossils: Mammals evolved faster after dinosaur extinction

    Fossils: Mammals evolved faster after dinosaur extinction

    Our ancestors evolved three times faster in the 10 million years after the extinction of the dinosaurs than in the previous 80 million years, according to UCL researchers.

    Mammals evolved faster after dinosaur extinction
    Late cretaceous dinosaurs [Credit: UCL]

    The team found the speed of evolution of placental mammals -- a group that today includes nearly 5000 species including humans -- was constant before the extinction event but exploded after, resulting in the varied groups of mammals we see today.

    Lead researcher, Dr Thomas Halliday (UCL Genetics, Evolution & Environment), said: "Our ancestors -- the early placental mammals - benefitted from the extinction of non-avian dinosaurs and dwindling numbers of competing groups of mammals. Once the pressure was off, placental mammals suddenly evolved rapidly into new forms.

    "In particular, we found a group called Laurasiatheria quickly increased their body size and ecological diversity, setting them on a path that would result in a modern group containing mammals as diverse as bats, cats, rhinos, whales, cows, pangolins, shrews and hedgehogs."

    The team found that the last common ancestor for all placental mammals lived in the late Cretaceous period, about three million years before the non-avian dinosaurs became extinct 66 million years ago. This date is 20 million years younger than suggestions from previous studies which used molecular data from living mammals and assumed a near-constant rate of evolution.

    In this study, funded by the Natural Environment Research Council and published in >Proceedings B of the Royal Society, the researchers analysed fossils from the Cretaceous to the present day, and used the dates of their occurrence in the fossil record to estimate the timing of divergences based on an updated tree of life. The new tree was released by the same team in 2015 and has the largest representation of Paleocene mammals to date.

    The scientists measured all the small changes in the bones and teeth of 904 placental fossils and mapped the anatomical differences between species on the tree of life. From measuring the number of character changes over time for each branch, they found the average rate of evolution for early placental mammals both before and after the dinosaur extinction event. They compared the average rate of evolution over the geological stages before the extinction and the geological stages after to see what impact it had.

    Senior author, Professor Anjali Goswami (UCL Genetics, Evolution & Environment and UCL Earth Sciences), said: "Our findings refute those of other studies which overlooked the fossils of placental mammals present around the last mass extinction. Using rigorous methods, we've successfully tracked the evolution of early placental mammals and reconstructed how it changed over time. While the rate differed between species, we see a clear and massive spike in the rates of evolution straight after the dinosaurs become extinct, suggesting our ancestors greatly benefitted from the demise of the dinosaurs. The huge impact of the dinosaur extinction on the evolution of our ancestors really shows how important this event was in shaping the modern world."

    Professor Paul Upchurch (UCL Earth Sciences), co-author of the study, added: "Our large and refined data set allows us to build a clearer picture of evolutionary history. We plan on using it to study other large-scale evolutionary patterns such as how early placental mammals dispersed across the continents via land bridges that no longer exist today."

    Source: University College London [June 28, 2016]

  • Fossils: Mammal diversity exploded immediately after dinosaur extinction

    Fossils: Mammal diversity exploded immediately after dinosaur extinction

    The diversity of mammals on Earth exploded straight after the dinosaur extinction event, according to UCL researchers. New analysis of the fossil record shows that placental mammals, the group that today includes nearly 5000 species including humans, became more varied in anatomy during the Paleocene epoch - the 10 million years immediately following the event.

    Mammal diversity exploded immediately after dinosaur extinction
    Leptictis [Credit: Dr Thomas Halliday]

    Senior author, Dr Anjali Goswami (UCL Genetics, Evolution & Environment), said: "When dinosaurs went extinct, a lot of competitors and predators of mammals disappeared, meaning that a great deal of the pressure limiting what mammals could do ecologically was removed. They clearly took advantage of that opportunity, as we can see by their rapid increases in body size and ecological diversity. Mammals evolved a greater variety of forms in the first few million years after the dinosaurs went extinct than in the previous 160 million years of mammal evolution under the rule of dinosaurs."

    The Natural Environment Research Council-funded research, published today in the Biological Journal of the Linnean Society, studied the early evolution of placental mammals, the group including elephants, sloths, cats, dolphins and humans. The scientists gained a deeper understanding of how the diversity of the mammals that roamed the Earth before and after the dinosaur extinction changed as a result of that event.

    Placental mammal fossils from this period have been previously overlooked as they were hard to place in the mammal tree of life because they lack many features that help to classify the living groups of placental mammals. Through recent work by the same team at UCL, this issue was resolved by creating a new tree of life for placental mammals, including these early forms, which was described in a study published in Biological Reviews yesterday.

    First author of both papers, Dr Thomas Halliday (UCL Earth Sciences and Genetics, Evolution & Environment), said: "The mass extinction that wiped out the dinosaurs 66 million years ago is traditionally acknowledged as the start of the 'Age of Mammals' because several types of mammal appear for the first time immediately afterwards.

    "Many recent studies suggest that little changed in mammal evolution during the Paleocene but these analyses don't include fossils from that time. When we look at the mammals that were present, we find a burst of evolution into new forms, followed by specialisation that finally resulted in the groups of mammals we see today. The earliest placental mammal fossils appear only a few hundred thousand years after the mass extinction, suggesting the event played a key role in diversification of the mammal group to which we belong."

    The team studied the bones and teeth of 904 placental fossils to measure the anatomical differences between species. This information was used to build an updated tree of life containing 177 species within Eutheria (the group of mammals including all species more closely related to us than to kangaroos) including 94 from the Paleocene - making it the tree with the largest representation from Paleocene mammals to date. The new tree was analysed in time sections from 140 million years ago to present day, revealing the change in the variety of species.

    Three different methods were used by the team to investigate the range and variation of the mammals present and all showed an explosion in mammal diversity after the dinosaur extinction. This is consistent with theories that mammals flourished when dinosaurs were no longer hunting them or competing with them for resources.

    Dr Anjali Goswami (UCL Genetics, Evolution & Environment), added: "Extinctions are obviously terrible for the groups that go extinct, non-avian dinosaurs in this case, but they can create great opportunities for the species that survive, such as placental mammals, and the descendants of dinosaurs: birds."

    Professor Paul Upchurch (UCL Earth Sciences), co-author of the Biological Reviews study, added: "Several previous methodological studies have shown that it is important to include as many species in an evolutionary tree as possible: this generally improves the accuracy of the tree. By producing such a large data set, we hope that our evolutionary tree for Paleocene mammals is more robust and reliable than any of the previous ones. Moreover, such large trees are very useful for future studies of large-scale evolutionary patterns, such as how early placental mammals dispersed across the continents via land bridges that no longer exist today."

    The team are now investigating rates of evolution in these mammals, as well as looking at body size more specifically. Further work will involve building data from DNA into these analyses, to extend these studies to modern mammals.

    Source: University College London [December 21, 2015]

  • Natural Heritage: Scientists warn only 'simplified', degraded tropical forest may remain by end of century

    Natural Heritage: Scientists warn only 'simplified', degraded tropical forest may remain by end of century

    A new and more dangerous phase of impacts on the world's remaining tropical forests is emerging, threatening to simplify the world's most diverse ecosystem including mass species loss, according to new UCL-led research published today in Science.

    Scientists warn only 'simplified', degraded tropical forest may remain by end of century
    Deforestation in Tesso Nilo, Sumatra [Credit: WWF]

    The impact of humans on these areas has been increasing for millennia and today more than three-quarters of the world's remaining tropical forests have been degraded by human actions.

    The scientists identified three prior phases of expanding impacts, the first when hunter-gatherers moved into tropical forests and the second following the emergence of tropical agriculture, some 6,000 years ago. Under both, the overall health of tropical forests was maintained.

    Today, we live in the third phase, marked by much greater impacts, with distant decision-makers directing how land is used, including permanent intensive agriculture, often for soybeans or palm oil, frontier industrial logging for timber export, cross-continental species invasions, and early climate change impacts. The scientists term this phase the era of 'Global Integration', affecting even the most remote areas.

    Lead author, tropical forest expert Dr Simon Lewis (UCL Geography and University of Leeds) said: "Earth has lost 100 million hectares of tropical forest over the last 30 years, mostly to agricultural developments. Few people think about how intertwined with tropical forests we all are. Many foodstuffs include palm oil which comes from once pristine Asian tropical forest, while remaining intact forests are buffering the rate of climate change by absorbing about a billion tonnes of carbon each year."

    Current trends look set to intensify without major policy changes, as global food demand is projected to double, over 25 million kilometres of road are predicted to be built by 2050, and climate change intensifies, ushering in a new phase of human dominance of tropical forests.

    Dr Lewis added: "I fear a global simplification of the world's most complex forests. Deforestation, logging and road building all create fragmented patches of forest. However, as the climate rapidly changes the plants and animals living in the rainforest will need to move to continue to live within their ecological tolerances. How will they move? This is a recipe for the mass extinction of tropical forest species this century.

    "What is needed are unbroken areas of forest that link today's core tropical regions with forest areas about 4 degrees cooler, so as temperatures rise and rainfall patterns change species have a better chance of surviving rapid 21st century climate change. We need to bring conservation in line with the reality of climate change."

    The authors note that while deforestation and degradation continue, more optimistically, logged forest retains many environmental benefits, and marginal agricultural lands are being abandoned, which can return back to forest.

    Dr David Edwards (University of Sheffield), co-author of the study, said: "Much biodiversity still remains in selectively logged forests, and can recover in secondary forests that grow on abandoned farmland. There is abundant potential to incorporate these forests into global plans to make tropical biodiversity climate change ready.

    "Despite their value for biodiversity, logged-over and old secondary forests are frequently threatened by conversion to species-poor agricultural plantations. We urgently need to protect these human-impacted forests, especially in regions such as Southeast Asia where almost nowhere is left undegraded."

    A suite of policy measures can help tropical forests survive, including giving forest dwellers formal collective legal rights over their land, which previous studies have shown is one of the best ways of preserving forests. A study of 292 protected areas in Amazonia showed that indigenous reserves were the most effective at avoiding deforestation in high pressure areas.

    Most of the financial benefits of logging and plantation agriculture, such as palm oil, flow out of the forests. Ensuring local people have collective long-term rights over their lands would mean that benefits flowing from forest lands accrue to local people. This can provide the beginnings of programs of 'development without destruction', tackling poverty while maintaining forests. This, the authors argue, provides human rights and conservation win-wins.

    Dr Lewis added: "With long-term certainty of tenure people can plan, maintaining forests while investing in improving agricultural productivity without expanding into forested lands. Forest dwellers won't be perfect managers of forests, but they won't look for a quick profit and then move on, as big businesses often do.

    "This is a pivotal year for the global environment. There are some good signs for the world's tropical forests, with the UN New York Declaration on Forests agreeing to not only halt deforestation, but also restore 150 million hectares of forest. However, there are ominous signs too, with the palm oil industry having driven the world's highest deforestation rates in South East Asia now gearing up to repeat this process across Africa.

    "The Paris climate change talks in December are doubly important for forests and forest communities. The levels of emission cuts will be a critical factor in determining how many tropical forest plants and animals go extinct over the coming decades and centuries. The agreements on reducing deforestation, including durable finance, will be pivotal. The final test will be whether some funds for adaptation will include land-use planning to retain forest connectivity as the climate rapidly changes."

    Source: University College London [August 24, 2015]

  • UK: Ancient Britons' teeth reveal people were 'highly mobile' 4,000 years ago

    UK: Ancient Britons' teeth reveal people were 'highly mobile' 4,000 years ago

    Archaeologists have created a new database from the teeth of prehistoric humans found at ancient burial sites in Britain and Ireland that tell us a lot about their climate, their diet and even how far they may have travelled. In a paper, led by Dr Maura Pellegrini from the University of Oxford, researchers say that individuals in prehistoric Britain were highly mobile.

    Ancient Britons' teeth reveal people were 'highly mobile' 4,000 years ago
    Ancient Britons' teeth were analysed for clues as to where they had grown up 
    [Credit: Mandy Jay]

    The study is part of the international Beaker People project lead by Professor Mike Parker Pearson of University College London, and involves scientists from many institutions, including the universities of Oxford, Durham, Bradford, University College London, and the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. The paper says most of the teeth in the collection date back to Chalcolithic and Early Bronze Age periods (from 2500 to 1500 BC) and the analysis, published in the journal >Scientific Reports, suggests not only were people moving around their own country but may also have travelled to and from continental Europe.

    Researchers describe how tests on tooth fragments using an oxygen isotope analysis of tooth enamel provides evidence of where an individual lived when the tooth formed. Oxygen, a naturally occurring element in the environment, is absorbed by plants and animals and fixed in the mineral component of mammalian teeth, with an isotopic composition related to the environment in which that individual spent their childhood.  Based on the theory that prehistoric people would have sourced water and food locally, the team were able to geographically map the oxygen isotopic variability in the landscape of Britain and Ireland thereby providing a guide to where individuals sampled had lived as children.

    Ancient Britons' teeth reveal people were 'highly mobile' 4,000 years ago
    Woodhenge, one of the locations the variability in the isotope values was found to be particularly 
    marked in individuals [Credit: WikiCommons]

    An analysis of the teeth of those buried in the Stonehenge region, the Peak District, and the hills of the Yorkshire Wolds (in East Riding and North Yorkshire) show many were not 'local' to their final resting place. They were drawn from far and wide, sometimes to focal points containing sacred monuments. The variability in the isotope values was found to be particularly marked in individuals recovered from Woodhenge, a timber circle situated near Stonehenge; Bee Low, a Bronze Age round cairn in the Peak District, and Garton Slack in Yorkshire where there is a complex range of barrow types and burial practices.

    Tooth enamel fragments from 261 individual teeth were tested with researchers focusing on the central part of the tooth crown in each case. The teeth sampled from these individuals mineralise from the age of two years up to 8 years old, providing the clues to the environmental conditions, including the water they drank as a child. The possibility that people were outsiders who came into areas where they eventually died was calculated by comparing their values with the 'isoscape' information gleaned from most of the other samples in each area, as it was assumed the latter represented 'local' individuals. As individuals' signatures in the teeth were matched with areas where the majority, or 'local' people, were found, the researchers identified those who had lived in other areas as children.

    Source: University of Oxford [October 08, 2016]

  • Geology: Signs of ancient mega-tsunami could portend modern hazard

    Geology: Signs of ancient mega-tsunami could portend modern hazard

    Scientists working off west Africa in the Cape Verde Islands have found evidence that the sudden collapse of a volcano there tens of thousands of years ago generated an ocean tsunami that dwarfed anything ever seen by humans. The researchers say an 800-foot wave engulfed an island more than 30 miles away. The study could revive a simmering controversy over whether sudden giant collapses present a realistic hazard today around volcanic islands, or even along more distant continental coasts. The study appears today in the journal Science Advances.

    Signs of ancient mega-tsunami could portend modern hazard
    Geologists think that the eastern slope of Fogo volcano crashed into the sea some 
    65,000 to 124,000 years ago, leaving a giant scar where a new volcano can be
     seen growing in this satellite image [Credit: NASA]

    "Our point is that flank collapses can happen extremely fast and catastrophically, and therefore are capable of triggering giant tsunamis," said lead author Ricardo Ramalho, who did the research as a postdoctoral associate at Columbia University's Lamont-Doherty Earth Observatory, where he is now an adjunct scientist. "They probably don't happen very often. But we need to take this into account when we think about the hazard potential of these kinds of volcanic features."

    The apparent collapse occurred some 73,000 years ago at the Fogo volcano, one of the world's largest and most active island volcanoes. Nowadays, it towers 2,829 meters (9,300 feet) above sea level, and erupts about every 20 years, most recently last fall. Santiago Island, where the wave apparently hit, is now home to some 250,000 people.

    There is no dispute that volcanic flanks present a hazard; at least eight smaller collapses have occurred in Alaska, Japan and elsewhere in the last several hundred years, and some have generated deadly tsunamis. But many scientists doubt whether big volcanoes can collapse with the suddenness that the new study suggests. Rather, they envision landslides coming in gradual stages, generating multiple, smaller tsunamis. A 2011 French study also looked at the Fogo collapse, suggesting that it took place somewhere between 124,000-65,000 years ago; but that study says it involved more than one landslide. The French researchers estimate that the resulting multiple waves would have reached only 45 feet--even at that, enough to do plenty of harm today.

    A handful of previous other studies have proposed much larger prehistoric collapses and resulting megatsunamis, in the Hawaiian islands, at Italy's Mt. Etna, and the Indian Ocean's Reunion Island. But critics have said these examples are too few and the evidence too thin. The new study adds a new possible example; it says the estimated 160 cubic kilometers (40 cubic miles) of rock that Fogo lost during the collapse was dropped all at once, resulting in the 800-foot wave. By comparison, the biggest known recent tsunamis, which devastated the Indian Ocean's coasts in 2004 and eastern Japan in 2011, reached only about 100 feet. (Like most other well documented tsunamis, these were generated by movements of undersea earthquake faults--not volcanic collapses.)

    Signs of ancient mega-tsunami could portend modern hazard
    On a clear day, from these cliffs in northern Santiago island, it is 
    possible to see a silhouette of Fogo, nearly 40 miles away. The geologists 
    on this ridge believe that a tsunami generated by Fogo's sudden collapse 
    generated a wave that swept the spot where they are standing 
    [Credit: Kim Martineau/Lamont-Doherty Earth Observatory]

    Santiago Island lies 55 kilometers (34 miles) from Fogo. Several years ago, Ramalho and colleagues were working on Santiago when they spotted unusual boulders lying as far as 2,000 feet inland and nearly 650 feet above sea level. Some are as big as delivery vans, and they are utterly unlike the young volcanic terrain on which they lie. Rather, they match marine-type rocks that ring the island's shoreline: limestones, conglomerates and submarine basalts. Some weigh up to 770 tons. The only realistic explanation the scientists could come up with: A gigantic wave must have ripped them from the shoreline and lofted them up. They derived the size of the wave by calculating the energy it would have taken to accomplish this feat.

    To date the event, in the lab Ramalho and Lamont-Doherty geochemist Gisela Winckler measured isotopes of the element helium embedded near the boulders' surfaces. Such isotopes change depending on how long a rock has been lying in the open, exposed to cosmic rays. The analyses centered around 73,000 years--well within the earlier French estimate of a smaller event. The analysis "provides the link between the collapse and impact, which you can make only if you have both dates," said Winckler.

    Tsunami expert Bill McGuire, a professor emeritus at University College London who was not involved in the research, said the study "provides robust evidence of megatsunami formation [and] confirms that when volcanoes collapse, they can do so extremely rapidly." Based on his own work, McGuire s says that such megatsunamis probably come only once every 10,000 years. "Nonetheless," he said, "the scale of such events, as the Fogo study testifies, and their potentially devastating impact, makes them a clear and serious hazard in ocean basins that host active volcanoes."

    Ramalho cautions that the study should not be taken as a red flag that another big collapse is imminent here or elsewhere. "It doesn't mean every collapse happens catastrophically," he said. "But it's maybe not as rare as we thought."

    Signs of ancient mega-tsunami could portend modern hazard
    The tsunami generated by Fogo's collapse apparently swept boulders like this one 
    from the shoreline up into the highlands of Santiago island. Here, a researcher
     chisels out a sample [Credit: Ricardo Ramalho]

    In the early 2000s, other researchers started publishing evidence that the Cape Verdes could generate large tsunamis. Others have argued that Spain's Canary Islands have already done so. Simon Day, a senior researcher at University College London has sparked repeated controversy by warning that any future eruption of the Canary Islands' active Cumbre Vieja volcano could set off a flank collapse that might form an initial wave 3,000 feet high. This, he says, could erase more than nearby islands. Such a wave might still be 300 feet high when it reached west Africa an hour or so later he says, and would still be 150 feet high along the coasts of North and South America. So far, such studies have raised mainly tsunamis of publicity, and vigorous objections from other scientists that such events are improbable. A 2013 study of deep-sea sediments by the United Kingdom's National Oceanography Centre suggests that the Canaries have probably mostly seen gradual collapses.

    Part of the controversy hangs not only on the physics of the collapses themselves, but on how efficiently resulting waves could travel. In 1792, part of Japan's Mount Unzen collapsed, hitting a series of nearby bays with waves as high as 300 feet, and killing some 15,000 people. On July 9, 1958, an earthquake shook 90 million tons of rock into Alaska's isolated Lituya Bay; this created an astounding 1,724-foot-high wave, the largest ever recorded. Two fishermen who happened to be in their boat that day were carried clear over a nearby forest; miraculously, they survived.

    These events, however, occurred in confined spaces. In the open ocean, waves created by landslides are generally thought to lose energy quickly, and thus to pose mainly a regional hazard. However, this is based largely on modeling, not real-world experience, so no one really knows how fast a killer wave might decay into a harmless ripple. In any case, most scientists are more concerned with tsunamis generated by undersea earthquakes, which are more common. When seabed faults slip, as they did in 2004 and 2011, they shove massive amounts of water upward. In deep water, this shows up as a mere swell at the surface; but when the swell reaches shallower coastal areas, its energy concentrates into in a smaller volume of water, and it rears up dramatically. The 2004 Indian Ocean earthquake and tsunami killed 230,000 people in 14 countries; the 2011 Tohoku event killed nearly 20,000 in Japan, and has caused a long-term nuclear disaster.

    James Hunt, a tsunami expert at the United Kingdom's National Oceanography Centre who was not involved in the study, said the research makes it clear that "even modest landslides could produce high-amplitude anomalous tsunami waves on opposing island coastlines." The question, he said, "is whether these translate into hazardous events in the far field, which is debatable."

    When Fogo erupted last year, Ramalho and other geologists rushed in to observe. Lava flows (since calmed down) displaced some 1,200 people, and destroyed buildings including a new volcano visitors' center. "Right now, people in Cape Verde have a lot more to worry about, like rebuilding their livelihoods after the last eruption," said Ramalho. "But Fogo may collapse again one day, so we need to be vigilant."

    Source: The Earth Institute at Columbia University [October 02, 2015]

  • Evolution: Sex cells evolved to pass on quality mitochondria

    Evolution: Sex cells evolved to pass on quality mitochondria

    Mammals immortalise their genes through eggs and sperm to ensure future generations inherit good quality mitochondria to power the body's cells, according to new UCL research.

    Sex cells evolved to pass on quality mitochondria
    One of a series of ova made in a spell of reproductive mitochondrial interest. The ovum about to ovulate has differentiated 
    from the rest of the surrounding tissue and is getting ready to leave the ovary. Its mitochondria are organized mainly 
    around the nucleus. The cell is full of potential and force. A big journey of life may be about to start 
    [Credit: Odra Noel]

    Before now, it was not known why mammals rely on dedicated sex cells that are formed early in development (a germline) to make offspring whereas plants and other simple animals, such as corals and sponges, use sex cells produced later in life from normal body tissues.

    In a new study, published today in >PLOS Biology and funded by Natural Environment Research Council, Engineering & Physical Sciences Research Council and the Leverhulme Trust, UCL scientists developed an evolutionary model to investigate how these differences evolved over time and discovered that the germline in mammals developed in response to selection on mitochondria (the powerhouses of cells).

    First author and UCL PhD student, Arunas Radzvilavicius, said: "There have been many theories about why mammals have a specialised germline when plants and other ancient animals don't. Some suggest it was due to complexity of tissues or a selfish conflict between cells. The distinction between sex cells and normal body tissues seems to be necessary for the evolution of very complex specialised tissues like brain.

    "Surprisingly, we found that these aren't the reason. Rather, it's about the number of genetic mutations in mitochondrial DNA over time, which differs between organisms, and the variation between cells caused by the mitochondria being randomly partitioned into daughter cells at each division."

    In plants, mitochondrial mutations creep in slowly, so a germline isn't needed as mutations are corrected by natural selection. Mitochondrial variation is maximised by forming the next generation from the same cells used to make normal tissue cells. When the cells divide to form new daughter cells, some receive more mutant mitochondria than others and these cells are then removed through natural selection, preserving the reproductive cells containing higher quality mitochondria.

    In mammals, genetic errors in mitochondria accumulate more quickly due to our higher metabolic rate so using cells that have undergone lots of division cycles would be a liability. Mitochondria are therefore only passed along to the next generation through a dedicated female germline in the form of large eggs. This protects against errors being introduced as eggs undergo many fewer replication cycles than cells in other tissues such as the gut, skin and blood.

    The germline ensures that the best quality mitochondria are transferred but restricts the genetic variation in the next generation of cells in the developing embryo. This is corrected for by mammals generating far too many egg cells which are removed during development. For example, humans are born with over 6 million egg-precursor cells, 90% of which are culled by the start of puberty in a mysterious process called atresia.

    Senior author, Dr Nick Lane (UCL CoMPLEX and Genetics, Evolution & Environment) added: "We think the rise in mitochondrial mutation rate likely occurred in the Cambrian explosion 550 million years ago when oxygen levels rose. This was the first appearance of motile animals in the fossil record, things like trilobites that had eyes and armour plating - predators and prey. By moving around they used their mitochondria more and that increased the mutation rate. So to avoid these mutations accumulating they needed to have fewer rounds of cell division, and that meant sequestering a specialized germline."

    Co-author, Professor Andrew Pomiankowski (UCL Genetics, Evolution & Environment), concluded: "Without a germline, animals with complex development and brains could not exist. Scientists have long tried to explain the evolution of the germline in terms of complexity. Who would have thought it arose from selection on mitochondrial genes? We hope our discovery will transform the way researchers understand animal development, reproduction and aging."

    Source: University College London [December 20, 2016]

  • Fossils: New Piltdown hoax analysis points to work of 'lone forger'

    Fossils: New Piltdown hoax analysis points to work of 'lone forger'

    The Piltdown Man scandal is arguably the greatest scientific fraud ever perpetrated in the UK, with fake fossils being claimed as evidence of our earliest ancestor.

    New Piltdown hoax analysis points to work of 'lone forger'
    The faked fossilized remains of Piltdown man (stained to look old), newspaper articles from the 1950s exposing the fraud.
      Inset: Charles Dawson, who the new article claims is probably the sole fraudster 
    [Credit: Natural History Museum]

    Published 100 years on from Dawson's death, new research reveals that the forgeries were created using a limited number of specimens that were all constructed using a consistent method, suggesting the perpetrator acted alone.

    It is highly likely that an orang-utan specimen and at least two human skeletons were used to create the fakes, which are still kept at the Natural History Museum.

    Between 1912 and 1914 Museum palaeontologist Arthur Smith Woodward and the amateur antiquarian Charles Dawson announced the discovery of fossils from Piltdown in Sussex. These were supposedly a new evolutionary link between apes and humans. They indicated a species with both an ape-like jaw and a large braincase like a modern human. Before he died in 1916, Dawson claimed to have discovered further evidence at a second site.

    The forgeries helped misdirect the study of anthropology for decades. While doubts were raised from the start, it took 40 years for the scientific community to recognise that the remains had been altered to seem ancient and had been planted in the sites.

    The new research, published in >Royal Society Open Science, was undertaken by a multi-disciplinary team from institutions in Liverpool, London, Cambridge and Canterbury. They used the latest scientific methods to test the Piltdown specimens to uncover more about how the forgery was done.

    New Piltdown hoax analysis points to work of 'lone forger'
    Surface modifications of Piltdown I M 1 : (A-B) photo and CT scans showing the material removal of the cusps in an 
    unnatural horizontal plane and enamel reconstruction on the lingual margin (C) Comparison of surface modifications 
    on different areas of the Piltdown I M 1 : Enamel (D), dentine (E), restorative putty (F), stained enamel (G)
    [Credit: De Groote et al./Natural History Museum]

    DNA analyses show that both the canine from the first Piltdown site and the molar from the second site probably came from one orang-utan, related most closely to orang-utans now occupying south-west Sarawak (Borneo). In addition, the shape and form of the molar from the second Piltdown site was almost certainly from the other side of the jawbone planted in the first site.

    3D X-ray imaging (Micro-CT scans) show that many of the bones and a tooth were filled with Piltdown gravel and the openings plugged with small pebbles. Holes in the skull bones were filled with dental putty, which was also used to re-set the teeth in the jaw and to reconstruct one of the teeth that fell apart while it was being ground down.

    Dr Laura Buck co-author on the paper from the Division of Biological Anthropology, University of Cambridge commented on the project's importance. "Even today, over a hundred years after the Piltdown fraud was perpetrated, it remains relevant because of the huge impact it had on the course of Palaeoanthropological research at the beginning of the twentieth century."

    "Fossil human remains from Africa, such as the Taung child from South Africa, were largely ignored when first found because they didn't fit with preconceptions of what an early human relative would look like, based on Piltdown Man. This serves as an important reminder to researchers today to study what is there and not what we think should be there," Buck said.

    Dr Isabelle De Groote from Liverpool John Moores University and lead author on the paper, thinks the results point to a clear conclusion: "Although multiple individuals have been accused of producing the fake fossils, our analyses to understand the modus operandi show consistency between all the different specimens and on both sites. It is clear from our analysis that this work was likely all carried out by one forger: Charles Dawson."

    Source: University of Cambridge [August 11, 2016]

  1. Maya: Secrets of their Ancient World in original exhibition at the Royal Ontario Museum
  2. Early archeology an adventure in plunder
  3. "Roads of Arabia" at the Sackler Gallery
  4. Roman water mill found during Cumbrian dig to go on display
  5. 'Celebrating the Arts of Japan: The Mary Griggs Burke Collection' at the Metropolitan Museum of Art