Started by Recusant, October 31, 2015, 01:52:11 AM
Quote from: Dark Lightning on July 13, 2019, 09:12:52 PMQuote from: xSilverPhinx on July 13, 2019, 03:29:11 PMQuote from: Dark Lightning on July 13, 2019, 03:06:09 AMFalse. I have this one book reprinted in the millions of copies that completely does not cover any of this "evolution" stuff. It MUST be correct! What!? [drops god hat] I truly love seeing this sort of information! It's so neat to see all the little pieces of the puzzle getting put together.Peer-reviewed by other sheepherders. Must be right. Got me there! Must be.
Quote from: xSilverPhinx on July 13, 2019, 03:29:11 PMQuote from: Dark Lightning on July 13, 2019, 03:06:09 AMFalse. I have this one book reprinted in the millions of copies that completely does not cover any of this "evolution" stuff. It MUST be correct! What!? [drops god hat] I truly love seeing this sort of information! It's so neat to see all the little pieces of the puzzle getting put together.Peer-reviewed by other sheepherders. Must be right.
Quote from: Dark Lightning on July 13, 2019, 03:06:09 AMFalse. I have this one book reprinted in the millions of copies that completely does not cover any of this "evolution" stuff. It MUST be correct! What!? [drops god hat] I truly love seeing this sort of information! It's so neat to see all the little pieces of the puzzle getting put together.
QuoteGenetic analysis has revealed that the ancestors of modern humans interbred with at least five different archaic human groups as they moved out of Africa and across Eurasia.While two of the archaic groups are currently known -- the Neandertals and their sister group the Denisovans from Asia -- the others remain unnamed and have only been detected as traces of DNA surviving in different modern populations. Island Southeast Asia appears to have been a particular hotbed of diversity.Published in the Proceedings of the National Academy of Sciences (PNAS), researchers from the University of Adelaide's Australian Centre for Ancient DNA (ACAD) have mapped the location of past "mixing events" (analysed from existing scientific literature) by contrasting the levels of archaic ancestry in the genomes of present-day populations around the world."Each of us carry within ourselves the genetic traces of these past mixing events," says first author Dr João Teixeira, Australian Research Council Research Associate, ACAD, at the University of Adelaide. "These archaic groups were widespread and genetically diverse, and they survive in each of us. Their story is an integral part of how we came to be.But as the ancestors of modern humans travelled further east they met and mixed with at least four other groups of archaic humans."Island Southeast Asia was already a crowded place when what we call modern humans first reached the region just before 50,000 years ago," says Dr Teixeira. "At least three other archaic human groups appear to have occupied the area, and the ancestors of modern humans mixed with them before the archaic humans became extinct."[Continues . . .]
QuoteThe fossil skull is the most complete specimen ever found in sediments older than 3 million years. Image Credit: Dale Omari/Cleveland Museum of Natural HistoryThe oldest most complete skull of a human ancestor ever discovered was found by chance by a local herder tending to his flock of goats in Ethiopia.The rare fossil is all that remains of a hominin with a brain the size of chimpanzee's, that roamed shrublands surrounding a lake 3.8 million years ago."This specimen is the most complete cranium ever found from sediments older than 3 million years," said Ethiopian palaeoanthropologist Yohannes Haile-Selassie, who co-led the scientific team.The discovery of the near complete skull puts a face on a critical gap in human evolution.With its wide cheekbones, long protruding jaw and large canine tooth, the fossil dubbed MRD, is the first to reveal the face of Australopithecus anamensis — the oldest-known species definitively part of the human evolutionary tree.The skull, detailed in the first of two papers in Nature, is set to rewrite our understanding of where A. anamensis fits between primitive hominins that lived more than 4 million years ago, and Australopithecus afarensis, the species made famous by the Lucy skeleton."It fills a gap in the fossil record from 3.6 to 3.9 million years and highlights some of the changes that took place from one species to another," Dr Haile-Selassie said.[Continues . . .]
QuoteResearchers have discovered a remarkably complete 3.8-million-year-old cranium of Australopithecus anamensis at Woranso-Mille in Ethiopia. The 3.8 million-year-old fossil cranium represents a time interval between 4.1 and 3.6 million years ago.Australopithecus anamensis is the earliest-known species of Australopithecus and widely accepted as the progenitor of 'Lucy's' species, Australopithecus afarensis. Until now, A. anamensis was known mainly from jaws and teeth. Yohannes Haile-Selassie of the Cleveland Museum of Natural History, Stephanie Melillo of the Max Planck Institute for Evolutionary Anthropology and their colleagues have discovered the first cranium of A. anamensis at the paleontological site of Woranso-Mille, in the Afar Region of Ethiopia.The 3.8 million-year-old fossil cranium represents a time interval between 4.1 and 3.6 million years ago, when A. anamensis gave rise to A. afarensis. Researchers used morphological features of the cranium to identify which species the fossil represents. "Features of the upper jaw and canine tooth were fundamental in determining that MRD was attributable to A. anamensis," said Melillo. "It is good to finally be able to put a face to the name." The MRD cranium, together with other fossils previously known from the Afar, show that A. anamensis and A. afarensis co-existed for approximately 100,000 years. This temporal overlap challenges the widely-accepted idea of a linear transition between these two early human ancestors. Haile-Selassie said: "This is a game changer in our understanding of human evolution during the Pliocene."[Continues . . .]
QuoteResearchers from the University of Copenhagen have succeeded in reconstructing the evolutionary relationship between a two million year old giant primate and the living orangutan. It is the first time genetic material this old has been retrieved from a fossil in a subtropical area. This allows the researchers to accurately reconstruct animal, including human, evolutionary processes way beyond the limits known today.By using ancient protein sequencing, researchers have retrieved genetic information from a 1.9 million year old extinct, giant primate that used to live in a subtropical area in southern China. The genetic information allows the researchers to uncover the evolutionary position of Gigantopithecus blacki, a three-meter tall and may be up to 600 kg heavy primate, revealing the orangutan as its closest, living relative.It is the first time that genetic material this old has been retrieved from a warm, humid environment. The study is published in the scientific journal Nature and is conducted in collaboration with the Institute of Evolutionary Biology in Barcelona. The results are groundbreaking within the field of evolutionary biology, according to Frido Welker, Postdoc at the Globe Institute at the Faculty of Health and Medical Sciences and first author of the study.[Continues . . .]
QuoteAn illustration of Danuvius guggenmosi, supporting itself with both its forelimbs and hindlimbs. Image Credit: Velizar SimeonovskiThe picture is on T-shirts, coffee mugs and bumper stickers: the ubiquitous but misinformed image of the evolution of humankind. A knuckle-walking ape rouses himself to stand on two feet, and over a 25-million-year "March of Progress," he becomes a modern man.Most paleoanthropologists will tell you that this version of evolution is oversimplified, misleading or just plain wrong. The theory that the last common ancestor of humans and apes walked on its knuckles like a chimpanzee is not supported by the fossil record, although it has seen popularity in scientific discourse. David Begun, a paleoanthropologist at the University of Toronto, used to be an outspoken proponent of the knuckle-walking hypothesis, until he was asked to consult on a newly discovered fossil that would challenge his assumptions about early hominid locomotion.When Madelaine Böhme, a researcher at the University of Tübingen in Germany, unearthed the partial skeleton of an ancient ape at the Hammerschmiede clay pit in Bavaria, she knew she was looking at something special. Compared to fragments, an intact partial skeleton can tell paleoanthropologists about a creature's body proportions and how its anatomy might have functioned. A relative newcomer to the field and a paleoclimatologist by trade, Böhme enlisted Begun's expertise in analyzing the fossil ape.Böhme and colleagues determined that the bones they found came from a dryopithecine ape, an extinct ancestor of humans and great apes that once lived in the Miocene epoch. The fossils are approximately 11.6 million years old and came from at least four individual apes, including one partial skeleton. The team described the newfound ancestor, named Danuvius guggenmosi, in a study published today in Nature.D. guggenmosi was likely a small primate about the size of baboon, with long arms like a bonobo. The creature had flexible elbows and strong hands capable of grasping, which suggests that it could have swung from tree to tree like a modern great ape. But the similarities with known apes stop there. The animal's lower limbs have much more in common with human anatomy. With extended hips and knees, D. guggenmosi was capable of standing with a straighter posture than that of living African apes, and its knees and ankles were adapted to bear weight. The animal's locomotion would have therefore shared similarities with both human and ape movement, and D. guggenmosi may have been able to navigate the forest by swinging from tree limbs and walking on two legs."There is no reason to think it would not have used all four limbs when that made sense, for example, on smaller branches where balance was an issue," Begun says. "But it was also capable of both chimp-like suspension and unassisted bipedalism."[Continues . . .]
QuoteArtistic reconstruction of the woman who chewed the birch pitch. She has been named Lola. Illustration by Tom Björklund.[From University of Copenhagen--a portrait of the birch pitch is available at this link. ]
QuoteResearchers from the University of Copenhagen have succeeded in extracting a complete human genome from a thousands-of-years old "chewing gum." According to the researchers, it is a new untapped source of ancient DNA.During excavations on Lolland, archaeologists have found a 5,700-year-old type of "chewing gum" made from birch pitch. In a new study, researchers from the University of Copenhagen succeeded in extracting a complete ancient human genome from the pitch.It is the first time that an entire ancient human genome has been extracted from anything other than human bones. The new research results have been published in the scientific journal Nature Communications.'It is amazing to have gotten a complete ancient human genome from anything other than bone,'' says Associate Professor Hannes Schroeder from the Globe Institute, University of Copenhagen, who led the research.'What is more, we also retrieved DNA from oral microbes and several important human pathogens, which makes this a very valuable source of ancient DNA, especially for time periods where we have no human remains,' Hannes Schroeder adds.Based on the ancient human genome, the researchers could tell that the birch pitch was chewed by a female. She was genetically more closely related to hunter-gatherers from the mainland Europe than to those who lived in central Scandinavia at the time. They also found that she probably had dark skin, dark hair and blue eyes.[Continues . . .]
QuoteAn international team of researchers has determined the age of the last known settlement of the species Homo erectus, one of modern humans' direct ancestors. The site is called Ngandong, on the Indonesian island Java. The team dated animal fragments where Homo erectus remains were found and the surrounding landscape. The team determined the last existence of Homo erectus at Ngandong between 108,000 and 117,000 years ago.Homo erectus, one of modern humans' direct ancestors, was a wandering bunch. After the species dispersed from Africa about two million years ago, it colonized the ancient world, which included Asia and possibly Europe.But about 400,000 years ago, Homo erectus essentially vanished. The lone exception was a spot called Ngandong, on the Indonesian island of Java. But scientists were unable to agree on a precise time period for the site -- until now.In a new study published in the journal Nature, an international team of researchers led by the University of Iowa; Macquarie University; and the Institute of Technology Bandung, Indonesia, dates the last existence of Homo erectus at Ngandong between 108,000 and 117,000 years ago.The researchers time-stamped the site by dating animal fossils from the same bonebed where 12 Homo erectus skull caps and two tibia had been found, and then dated the surrounding land forms -- mostly terraces below and above Ngandong -- to establish an accurate record for the primeval humans' possible last stand on Earth.[Continues . . .]
QuoteIn 1924, a 3-year-old child's skull found in South Africa forever changed how people think about human origins.The Taung Child, our first encounter with an ancient group of proto-humans or hominins called australopithecines, was a turning point in the study of human evolution. This discovery shifted the focus of human origins research from Europe and Asia onto Africa, setting the stage for the last century of research on the continent and into its "Cradles of Humankind."Few people back then would've been able to predict what scientists know about evolution today, and now the pace of discovery is faster than ever. Even since the turn of the 21st century, human origins textbooks have been rewritten over and over again. Just 20 years ago, no one could have imagined what scientists know two decades later about humanity's deep past, let alone how much knowledge could be extracted from a thimble of dirt, a scrape of dental plaque or satellites in space.[Continues . . .]
QuoteAn evolutionary tree including four proposed episodes of gene flow. The previously unknown event 744,372 years ago (orange) suggests interbreeding occurred between super-archaics and Neanderthal-Denisovan ancestors in Eurasia. Image: University of Utah--Alan RogersFor three years, anthropologist Alan Rogers has attempted to solve an evolutionary puzzle. His research untangles millions of years of human evolution by analyzing DNA strands from ancient human species known as hominins. Like many evolutionary geneticists, Rogers compares hominin genomes looking for genetic patterns such as mutations and shared genes. He develops statistical methods that infer the history of ancient human populations.In 2017, Rogers led a study which found that two lineages of ancient humans, Neanderthals and Denisovans, separated much earlier than previously thought and proposed a bottleneck population size. It caused some controversy—anthropologists Mafessoni and Prüfer argued that their method for analyzing the DNA produced different results. Rogers agreed, but realized that neither method explained the genetic data very well."Both of our methods under discussion were missing something, but what?" asked Rogers, professor of anthropology at the University of Utah.The new study has solved that puzzle and in doing so, it has documented the earliest known interbreeding event between ancient human populations—a group known as the "super-archaics" in Eurasia interbred with a Neanderthal-Denisovan ancestor about 700,000 years ago. The event was between two populations that were more distantly related than any other recorded. The authors also proposed a revised timeline for human migration out of Africa and into Eurasia. The method for analyzing ancient DNA provides a new way to look farther back into the human lineage than ever before."We've never known about this episode of interbreeding and we've never been able to estimate the size of the super-archaic population," said Rogers, lead author of the study. "We're just shedding light on an interval on human evolutionary history that was previously completely dark."The paper was published on Feb. 20, 2020, in the journal Science Advances.[Continues . . .]
QuoteAbstract:Previous research has shown that modern Eurasians interbred with their Neanderthal and Denisovan predecessors. We show here that hundreds of thousands of years earlier, the ancestors of Neanderthals and Denisovans interbred with their own Eurasian predecessors—members of a "superarchaic" population that separated from other humans about 2 million years ago. The superarchaic population was large, with an effective size between 20 and 50 thousand individuals. We confirm previous findings that (i) Denisovans also interbred with superarchaics, (ii) Neanderthals and Denisovans separated early in the middle Pleistocene, (iii) their ancestors endured a bottleneck of population size, and (iv) the Neanderthal population was large at first but then declined in size. We provide qualified support for the view that (v) Neanderthals interbred with the ancestors of modern humans.
QuoteAn ancient, humanlike population still undiscovered in fossils left a genetic legacy in present-day West Africans, a new study suggests.These extinct relatives of Homo sapiens passed genes to African ancestors of modern Yoruba and Mende people starting around 124,000 years ago or later, say UCLA geneticists Arun Durvasula and Sriram Sankararaman. Surviving DNA of those ancient hominids is different enough from that of Neandertals and Denisovans to suggest an entirely different hominid was the source.Yoruba and Mende groups' genomes contain from 2 to 19 percent of genetic material from this mysterious "ghost population," the scientists report February 12 in Science Advances. Some DNA segments passed down from the mysterious Homo species influence survival-enhancing functions, including tumor suppression and hormone regulation. Those genes likely spread rapidly among modern West Africans, the investigators suspect.DNA from Han Chinese in Beijing as well as Utah residents with northern and western European ancestry also showed signs of ancestry from the ancient ghost population, Durvasula and Sankararaman found. But DNA from those two groups was not studied as closely as that from the Yoruba and Mende people.[Continues . . .]
QuoteAbstract:While introgression from Neanderthals and Denisovans has been documented in modern humans outside Africa, the contribution of archaic hominins to the genetic variation of present-day Africans remains poorly understood. We provide complementary lines of evidence for archaic introgression into four West African populations. Our analyses of site frequency spectra indicate that these populations derive 2 to 19% of their genetic ancestry from an archaic population that diverged before the split of Neanderthals and modern humans. Using a method that can identify segments of archaic ancestry without the need for reference archaic genomes, we built genome-wide maps of archaic ancestry in the Yoruba and the Mende populations. Analyses of these maps reveal segments of archaic ancestry at high frequency in these populations that represent potential targets of adaptive introgression. Our results reveal the substantial contribution of archaic ancestry in shaping the gene pool of present-day West African populations.
QuoteTwo studies of ancient humans have shed new light on the last common ancestor we share with Neanderthals. An extinct species that was once in the frame now looks unlikely to be the one. Another now seems more plausible, but it may only be related to the ancestor."My guess is we haven't found the common ancestor yet," says Chris Stringer of the Natural History Museum in London. However, the new findings clarify what the common ancestor may have looked like.Stringer's team studied a skull called Kabwe 1, which was discovered in 1921 by miners at Broken Hill in what is now Zambia. "It was the first important [hominin] fossil found in Africa," says Stringer. It probably belonged to a young male and had a primitive-looking face with "huge brow ridges over the eyes".Many anthropologists place Kabwe 1 in Homo heidelbergensis, which ranged across Africa and Europe between about 700,000 and 300,000 years ago. It has long been a candidate for the common ancestor of three later groups: modern humans (Homo sapiens), the Neanderthals of Europe and west Asia, and the Denisovans of east Asia.However, until now the Kabwe skull's age has been a mystery. The normal approach is to date the surrounding sediments, says Rainer Grün of Griffith University in Australia. But the skull was found by accident and the site quarried, so researchers have no sediments to test. The general assumption has been that the skull is about 500,000 years old, but it has not been possible to assess that idea properly."The only thing we could do is to analyse the skull itself," says Grün. This is only now possible. Older methods would have required drilling into the skull, causing "unacceptable" damage. Instead, the team used lasers to remove fragments a quarter of a millimetre thick.Analyses of these fragments indicate Kabwe 1 is about 299,000 years old.[. . .]The age of Kabwe 1 means the skull probably didn't belong to an ancestor of humans, Neanderthals and Denisovans, says Stringer. Genetic evidence suggests the last common ancestor lived about 600,000 years ago, so Kabwe 1 is too recent. There is also evidence that modern humans were present in northern Africa 300,000 years ago, about the same time Kabwe 1 was alive."We reassess it as a separate line of evolution, but one which probably coexisted with the evolution of Homo sapiens," says Stringer.[. . .]A better candidate for the common ancestor is Homo antecessor, says José María Bermúdez de Castro of the National Centre for Research on Human Evolution in Spain. These hominins lived in northern Spain between 1.2 million and 800,000 years ago."H. antecessor shows a unique combination of dental and skeletal features," says Bermúdez de Castro. Its face was quite modern: more like ours than like that of H. heidelbergensis.His colleagues have now extracted seven proteins from an H. antecessor tooth from about 860,000 years ago. This represents a major breakthrough. "We are able to reliably retrieve ancient human protein sequences over the past 2 million years," says Frido Welker at the University of Copenhagen in Denmark.By comparing the H. antecessor proteins with those of other hominins, the team has found that the species was closely related to the last common ancestors of humans, Neanderthals and Denisovans. However, the researchers cannot tell if it actually was the ancestor. "It is too early to conclude this confidently," says Enrico Cappellini at the University of Copenhagen.[Continues . . .]
QuoteGenetic information from an 800,000-year-old human fossil has been retrieved for the first time. The results from the University of Copenhagen shed light on one of the branching points in the human family tree, reaching much further back in time than previously possible.An important advancement in human evolution studies has been achieved after scientists retrieved the oldest human genetic data set from an 800,000-year-old tooth belonging to the hominin species Homo antecessor.The findings by scientists from the University of Copenhagen (Denmark), in collaboration with colleagues from the CENIEH (National Research Center on Human Evolution) in Burgos, Spain, and other institutions, are published April 1st in Nature."Ancient protein analysis provides evidence for a close relationship between Homo antecessor, us (Homo sapiens), Neanderthals, and Denisovans. Our results support the idea that Homo antecessor was a sister group to the group containing Homo sapiens, Neanderthals, and Denisovans," says Frido Welker, Postdoctoral Research Fellow at the Globe Institute, University of Copenhagen, and first author on the paper.[. . .]The fossils analyzed by the researchers were found by palaeoanthropologist José María Bermúdez de Castro and his team in 1994 in stratigraphic level TD6 from the Gran Dolina cave site, one of the archaeological and paleontological sites of the Sierra de Atapuerca, Spain.Initial observations led to conclude that Homo antecessor was the last common ancestor to modern humans and Neanderthals, a conclusion based on the physical shape and appearance of the fossils. In the following years, the exact relation between Homo antecessor and other human groups, like ourselves and Neanderthals, has been discussed intensely among anthropologists.Although the hypothesis that Homo antecessor could be the common ancestor of Neanderthals and modern humans is very difficult to fit into the evolutionary scenario of the genus Homo, new findings in TD6 and subsequent studies revealed several characters shared among the human species found in Atapuerca and the Neanderthals. In addition, new studies confirmed that the facial features of Homo antecessor are very similar to those of Homo sapiens and very different from those of the Neanderthals and their more recent ancestors."I am happy that the protein study provides evidence that the Homo antecessor species may be closely related to the last common ancestor of Homo sapiens, Neanderthals, and Denisovans. The features shared by Homo antecessor with these hominins clearly appeared much earlier than previously thought. Homo antecessor would therefore be a basal species of the emerging humanity formed by Neanderthals, Denisovans, and modern humans," adds José María Bermúdez de Castro, Scientific Co-director of the excavations in Atapuerca and co-corresponding author on the paper.[Continues . . .]
QuoteTwo studies report new Homo sapiens fossils from the site of Bacho Kiro Cave in Bulgaria. "The Bacho Kiro Cave site provides evidence for the first dispersal of H. sapiens across the mid-latitudes of Eurasia. Pioneer groups brought new behaviours into Europe and interacted with local Neanderthals. This early wave largely predates that which led to their final extinction in western Europe 8,000 years later", says Jean-Jacques Hublin, director at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.An international research team, led by Jean-Jacques Hublin, Tsenka Tsanova and Shannon McPherron of the Max Planck Institute for Evolutionary Anthropology, and Nikolay Sirakov and Svoboda Sirakova of the National Institute of Archaeology with Museum at the Bulgarian Academy of Sciences in Sofia, Bulgaria, renewed excavations at Bacho Kiro Cave in 2015. The most spectacular finds come from a rich, dark layer near the base of the deposits. Here the team uncovered thousands of animal bones, stone and bone tools, beads and pendants and the remains of five human fossils.Except for one human tooth, the human fossils were too fragmented to be recognized by their appearance. Instead, they were identified by analysing their protein sequences. "Most Pleistocene bones are so fragmented that by eye, one cannot tell which species of animal they represent. However, the proteins differ slightly in their amino acid sequence from species to species. By using protein mass spectrometry, we can therefore quickly identify those bone specimens that represent otherwise unrecognizable human bones", says Frido Welker, Postdoctoral Research Fellow at the University of Copenhagen and research associate at the Max Planck Institute for Evolutionary Anthropology.To know the age of these fossils and the deposits at Bacho Kiro Cave, the team worked closely with Lukas Wacker at ETH Zurich, Switzerland, using an accelerator mass spectrometer to produce ages with higher precision than normal and to directly date the human bones."The majority of animal bones we dated from this distinctive, dark layer have signs of human impacts on the bone surfaces, such as butchery marks, which, along with the direct dates of human bones, provides us with a really clear chronological picture of when Homo sapiens first occupied this cave, in the interval from 45,820 to 43,650 years ago, and potentially as early as 46,940 years ago", says Helen Fewlass of the Max Planck Institute for Evolutionary Anthropology. "The radiocarbon dates at Bacho Kiro Cave are not only the largest dataset of a single Palaeolithic site ever made by a research team, but also are the most precise in terms of error ranges", say researchers Sahra Talamo from the University of Bologna and Bernd Kromer from the Max Planck Institute in Leipzig.[Continues . . .]