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European Roots: Human ancestors go back in time in Spanish cave
Bruce Bower Fossil finds in Spain have yielded the earliest known skeletal evidence of human ancestors in Europe, according to a new report. A fossil jaw and tooth from the same individual, found during excavations of a cave called Sima del Elefante in northern Spain's Atapuerca Mountains, date to between 1.2 million and 1.1 million years old, say anthropologist Eudald Carbonell of Universitat Rovira i Virgili in Tarragona, Spain, and his colleagues.
The investigators assign the new discoveries to the species Homo antecessor. A decade ago, they identified 800,000-year-old fossils from another Atapuerca site as H. antecessor. In the Spanish scientists' view, H. antecessor was an evolutionary precursor of European Neandertals and modern humans. Many scientists remain skeptical of that proposal and classify the Spanish fossils as the oldest examples of Homo heidelbergensis, a roughly 600,000-year-old species first found in Germany a century ago. However this debate plays out, the Sima del Elefante fossils "provide the oldest direct evidence, to our knowledge, for a human presence in Europe," Carbonell says. Anthropologist Bernard Wood of George Washington University in Washington, D.C., agrees that the find provides the first solid evidence that human ancestors reached Europe more than 1 million years ago. "Before this report, the evidence for an early occupation of Europe had substantial and important caveats," he says. The newly unearthed specimens were found in sediment that also contained stone tools, stone flakes produced during toolmaking, and numerous animal bones bearing butchery marks. Carbonell's team describes its work at Sima del Elefante in the March 27 Nature. Several lines of evidence provided an age estimate for the Spanish fossils. Reversals in Earth's magnetic field recorded in fossil-bearing sediments bracketed the fossils' age at between 1.78 million and 780,000 years old. The decay rate of certain radioactive isotopes in rock buried near the fossils—along with analyses of the types of now-extinct animals strewn among the finds—narrowed the age estimate down to 1.2 million to 1.1 million years old. The new finds strengthen earlier, contested evidence from other European sites—mainly consisting of stone implements, not fossils—that suggests human ancestors occupied the region at least 1 million years ago, Carbonell says. A broad anthropological consensus holds that large groups of human ancestors lived in Western Europe by 500,000 years ago. The Atapuerca investigators suggest that Western Europe was settled between 2 million and 1 million years ago by a Homo species that trekked out of Africa, perhaps into central Asia, and then moved westward. That species then evolved into H. antecessor, in their view. One possible ancestor of the ancient Atapuerca population has been found at the Dmanisi site in the central Asian nation of Georgia. Excavations there have yielded 1.77-million-year-old remains that may come from an early, highly mobile form of Homo erectus (SN: 9/22/07, p. 179). The Sima del Elefante fossils show no obvious anatomical links to the Dmanisi remains, Wood says. Still, an evolutionary connection between Dmanisi and Atapuerca is plausible, he says. It's unknown whether enough human ancestors entered Western Europe before 1 million years ago to establish a permanent presence in the region so that they could evolve into later European Homo species, Wood notes. |
Early human bipedalism confirmed
One such fossil, a 6-million-year-old thigh bone from a species called Orrorin tugenensis, is the topic of a new study published in Science yesterday. Despite previous examinations of this fossil, which was discovered in Kenya in 2000, researchers still debate whether O. tugenensis walked upright and whether it was more closely related to the australopithecines that lived 3 million to 2 million years ago or to the much later Homo. Brian G. Richmond of George Washington University in Washington, D.C., and William L. Jungers of Stony Brook University in New York write in Science that they have resolved the debate by determining that O. tugenensis did indeed walk upright and that its hip structure is more similar to the australopithecines. Richmond and Jungers based their conclusions about the species' bipedalism and hip mechanism on the shape of the thigh bone. Using calipers, they recorded many of the fossil's dimensions, and then compared their measurements through statistical analyses to various hominin and ape species. Determining that O. tugenensis was bipedal is significant, Richmond says, because it reduces the time window during which the hominin lineage could have originated to between about 6.5 million to 7 million years ago. The presence of not only bipedal but also more primitive tree-climbing traits in the species indicates that O. tugenensis is not far removed from the ape-human common ancestor but that it is "already in the human line," Richmond says. Robert Barry Eckhardt, an evolutionary biologist at Penn State University in University Park, says the study's findings that O. tugenensis was bipedal is not new: "[It] is just the same conclusion that my colleagues concluded on the basis of the very same evidence in 2001." Eckhardt says that the paper's hypothesis that O. tugenensis is more similar to Australopithecus afarensis than to modern Homo "may or may not be true," although he says the statistical data presented within the paper do not suggest that this is a strong possibility. Andrew T. Chamberlain, a biological anthropologist at the University of Sheffield in the United Kingdom, says that the study has quantitatively and convincingly established bipedalism in the specimen. The findings are significant, he says. Chamberlain agrees with the researchers that O. tugenensis shared a hip and gait mechanism with the much younger A. afarensis — such as the famed Lucy. As the femur "morphology is an early example of australopithecine," he says, it demonstrates that the hip mechanism was evolutionarily stable. He adds that more studies of A. afarensis might confirm this. |
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Neandertal Gene Study Reveals Early Split With Humans
Elizabeth Svoboda for National Geographic News October 26, 2006 A new genetic study bolsters theories of an early human-Neandertal split and is helping scientists pinpoint what makes humans unique. Controversy has long swirled in the scientific community over how closely the Eurasian hunters resembled modern humans, with some researchers even claiming Neandertals (often spelled Neanderthals) were actually members of our own species, Homo sapiens. (Related: "Neandertals' Last Stand Was in Gibraltar, Study Suggests" [September 13, 2006].) A new study by geneticist James Noonan at Lawrence Berkeley National Laboratory, however, reveals that modern humans and Neandertals' most recent common ancestor probably perished about 400,000 years ago. The research was presented earlier this month at the American Society of Human Genetics conference in New Orleans, Louisiana (get a genetics overview). Richard Potts, director of the human origins program at the National Museum of Natural History in Washington, D.C., called Noonan's work "highly significant." "Each part of the Neandertal genome is an archive of the similarity and distinction [between Neandertals and] all people living today," he said. "Comparison to a lineage in our own family tree helps us understand which elements of the genetic code make us human." Going Nuclear To obtain the raw material for his study, Noonan extracted DNA from fossilized Neandertal bones. Combing the samples for Neandertal-specific genetic sequences was a painstaking process bogged down by large amounts of contamination. "Most of the DNA we got was bacterial DNA from organisms that had colonized the specimens," Noonan said. "We can pick out the ancient DNA sequences because they're shorter and more degraded." After analyzing the genetic content of the sequences, Noonan and his colleagues began cataloging them in a library similar to that used to help organize the human genome. Initial results indicate Neandertals have contributed surprisingly little to modern humans' genetic makeup. Noonan's work represents a significant advance over earlier studies of Neandertal genetics, such as those conducted by William Goodwin of the University of Glasgow in Scotland. (Related: "Neandertals Not Our Ancestors, DNA Study Suggests" [May 14, 2003].) That early work involved analysis of mitochondrial DNA, which tends to stay preserved longer than DNA found inside the nuclei of cells. But Noonan analyzed nuclear DNA, which holds a much greater wealth of information. "Nuclear DNA is where all the biology is," Noonan said. "We want to understand how traits like language and cognition are encoded, and none of those traits can be found in mitochondrial DNA." Race to the Finish Like the multiple groups who worked simultaneously to sequence the human genome, Noonan faces competition from other inspired teams. Genetic anthropologist Svante Paabo of the Max Planck Institute in Leipzig, Germany, is working on a similar sequencing project using DNA from bone specimens belonging to a Neandertal who lived in Croatia about 45,000 years ago. "A Neandertal genome sequence will provide a catalog of all changes that happened in the human genome after humans separated from Neandertals, so it will be a wonderful tool for scientists who want to find out what makes modern humans unique," Paabo said. While Noonan's focus is on studying the sequences of Neandertal DNA he considers most significant—those he can compare to modern human DNA sequences—Paabo's goal is to sequence the entire Neandertal genome within two years. Based on his results to date, Paabo expects to see some surprises as his project proceeds. "Neandertal DNA is degraded in specific ways that we had not anticipated, and in some ways Neandertals actually look closer to humans than we had expected," he said. The Natural History Museum's Potts hopes Noonan's and Paabo's investigations, in addition to fleshing out Neandertals' genetic profile, will lend insight into their day-to-day existence, including the challenges they faced that shaped specific genetic adaptations. "The genetic analysis of Neandertals complements the study of fossils and the archaeological record of Neandertal behavior," he said. "All this evidence allows us to understand exactly how Neandertals lived and adapted to a changing world that eventually included our species." |
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9,000-Year-Old Drilled Teeth Are Work of Stone Age Dentists The
discovery of drilled teeth in a graveyard in Pakistan shows that
proto-dentists used hand-powered, flint-tipped drills 9,000 years
ago. 20,000-Year-Old Human Footprints Found in Australia Stacked like well-trod carpets, layers of mud from an ancient wetland have preserved the world's largest collection of ancient human fossil footprints. Americas Settled by Two Groups of Early Humans, Study Says At least two distinct groups of early humans colonized the Americas, a new study says, reviving the debate about who the first Americans were and when they arrived. Ancient "Weapons Factory" Found on Connecticut Ridge Ancient Global Warming Spurred Primates Into North America, Fossils Show A warm spell 55 million years ago created leafy land bridges that the world's first primates used to spread from Asia to North America, a new study shows. Ancient Britain Had Apartheid-Like Society, Study Suggests Invading Anglo-Saxons some 1,600 years ago used segregation and social hierarchy to nearly wipe out the culture and gene pool of native Britons, a new report says. Ancient Egyptian City Yields World's Oldest Glassworks Archaeologists have found the world's earliest known glassmaking facility, revealing the crucial role of glass in ancient trade and politics. "Atlantis" Eruption Twice as Big as Previously Believed, Study Suggests A volcanic eruption that may have inspired the myth of Atlantis was up to twice as large as previously believed, scientists say, making it the second-largest eruption in human history. Climate Change May Have Helped Humans Out of Africa, Study Says Early humans may have spread out of Africa after rapid climate change triggered advances in human thinking and behavior, new research suggests. Did Million-Year-Long Eruptions Cause Mass Extinction? Warming and acid rain caused by extensive volcanic activity might be the prime suspects in a quarter-billion-year-old whodunit, according to a new book. Did Climate Change Trigger Human Evolution? It may be a threat to humans' long-term future on the planet, but climate change may have helped bring us into being in the first place, some scientists say. Did Early Humans First Arise in Asia, Not Africa? Early Chiefdoms Offer Clues to Modern Wealth, Power, Study Says A study of three ancient communities sheds light on the historical differences between cultures around the globe, as well as how and why people learned to work together. Eagle Ancestors Hunted Early Humans, Skull Study Suggests Modern-day raptors can kill and eat primates more than twice the birds' body weight, suggesting that ancient eagles could have hunted early humans. Early Humans Settled Globe Gradually, Gene Study Says As populations' distance from Africa increases, genetic diversity decreases, according to a global DNA study. Researchers say the finding suggests early humans settled the planet in small steps. Early Humans May Have Crossed Sea to Leave Africa Two new genetic studies suggest modern humans left Africa between 60,000 to 75,000 years ago, crossing the Red Sea, then following the Indian Ocean coastline. Archaeologists say they have unearthed one of the largest collections of Stone Age skeletons and artifacts ever found in the Sahara. Earth's "Wobbles" Spurring Cycles of Evolution and Extinction? Regular wobbles in Earth's orbit and tilt may drive a recurring cycle of evolution and extinction, a new study says. Early Humans Settled India Before Europe, Study Suggests New research suggests that before reaching Europe modern humans arrived in India, where they created some of the earliest human culture and drove an older hominid species to extinction. Europeans Descended From Hunters, Not Farmers, Study Says Europeans owe their ancestry mainly to Stone Age hunters, not to later incomers who brought farming to Europe from the Middle East, new research suggests. European Faces Reflect Stone Age Ancestry, Study Says Evidence of 16th-Century Spanish Fort in Appalachia? Combing detective work with old-fashioned digging, archaeologists may have unearthed evidence that Spanish soldiers roamed Appalachia in the 16th century. Fossil Pushes Upright Walking Back 2 Million Years, Study Says A study of ancient cemeteries in North America suggests that a prehistoric baby boom swept the continent about 2,500 years ago, just as farming was taking root. Fossil Find Is Missing Link in Human Evolution, Scientists Say Fossil "Footprints" Stir Debate About Earliest Americans Footprintlike marks found in Mexico have recently been dated at over a million years old, renewing debate about when humans first arrived in the Americas. "Hobbits" Were Pygmy Ancestors, Not New Species, Study Says The latest analysis of fossils from the Indonesian island of Flores suggests that the tiny people are related to a pygmy population living on the island today. "Hobbit" Island Tools Predate Modern Humans, Study Says Long before modern humans, complex tools were being made on the island of the "hobbits," scientists say—fueling debate over whether they were a separate species. "Hobbit" Humans Were Diseased, Not New Species, Study Says The diminutive humans from Indonesia were not a unique species but a population of modern humans stricken with a disease that causes small brains, scientists argue Huge Vesuvius Eruption Buried Town 2,000 Years Before Pompeii Scientists studying Italy's volcanic past have discovered remains of a dramatic eruption that happened nearly 2,000 years before the blast that buried Pompeii. Ice Age Horses May Have Been Killed Off by Humans, Study Finds An ancient horse ancestor lived in North America at about the same time that early humans arrived on the scene, a new look at the fossil record reveals. 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Neandertal Gene Study Reveals Early Split With Humans New research is providing insights into how Neandertals and modern humans differ, helping scientists pinpoint what exactly makes humans unique. New Land-Bridge Evidence Adds to Mystery of 1st Americans The Asia-to-Alaska land bridge disappeared a thousand years earlier than thought, a new study says—fueling speculation that the first Americans arrived by boat. Neandertals Turned to Cannibalism, Bone Cave Suggests The brain-eating prehistoric humans also looked different from Neandertals elsewhere in Europe, a new study says. "Lucy" Fossil Tour Sparks Controversy Among U.S. Museums The nearly 3.2-million-year-old bones will start a six-year tour of the U.S. next year. But at least one museum is refusing to accept the display, saying the remains are too fragile to travel. Neandertals, Modern Humans Interbred, Bone Study Suggests Photo in the News: Extinct Dwarf Buffalo Discovered The tiny species found in the Philippines was much smaller than its modern relations, a find that could have implications for the processes that formed the famous "hobbit" humans Photo Gallery: "Lucy's Baby" Adds to Early-Human Record See photos of "Lucy's baby" and other Australopithecus afarensis fossils that represent some of the earliest human ancestors known. by." Neandertals' Last Stand Was in Gibraltar, Study Suggests Our heavy-browed competitors lasted 2,000 years longer than previously thought, a new cave find suggests—though not everyone agrees on the dates. Stone Age Elephant Found at Ancient U.K. Hunt Site A prehistoric elephant unearthed near London had been butchered and eaten raw by Stone Age humans, researchers say. Stone Age Britons Often Died From Brutal Blows, Skull Survey Says Analysis of ancient human skulls from the Neolithic period shows that Britain was once a brutal place to live. Video: Decoding Ancient Scrolls From Volcanic "Tomb" Mysterious scrolls found beneath the lava and ash of an ancient volcanic eruption have begun to give up their secrets. Join scientists as they reveal the papyruses' hidden words. "Missing Link" Human Skull Found in Africa, Scientists Say A Stone Age fossil unearthed in Ethiopia has features of both early and modern humans, according to researchers. Photo Gallery: "Lost Kingdom" Found on Volcanic Island Scientists say they have discovered the remains of the tiny "kingdom" of Tambora, thought to have been wiped out by the largest volcanic eruption in recorded history. "Lost Kingdom" Discovered on Volcanic Island in Indonesia Scientists have announced the discovery of a small "kingdom" thought to have been destroyed by the largest volcanic eruption in recorded history. Neandertals Hunted as Well as Humans, Study Says Fossil remains of animal prey in the republic of Georgia suggest Neandertals were more intelligent and resourceful than scientists previously thought. Neandertals Had Long Childhoods, Tooth Study Suggests Among primates, modern humans take a long time to reach adulthood, and so did Neandertals, according to a new tooth study. Prehistoric Graves Reveal Americas' First Baby Boom Stone Tools Reveal Humans Lived in Britain 700,000 Years Ago Early humans colonized northern Europe 200,000 years earlier than previously thought, as shown by ancient stone tools discovered along the British coast. Stone Age Cemetery, Artifacts Unearthed in Sahara Tomb of Prehistoric Leader Unearthed in Modern Rome Archaeologists working in the center of Rome discovered the tomb of an ancient chief or priest who lived three centuries before the city was founded. Spear Led to Era of Early-Human Peace, Expert Says The invention of the spear spurred a peaceful era that lasted from roughly one million to 14,000 years ago, one anthropologist says. Stone Age Cave Art, Artifacts Found in Borneo Bones and Stone Age artifacts found in Borneo caves etched with elaborate handprints and drawings suggest humans dined there 10,000 years ago. Tooth Study Reveals Diets of Early Humans Using new, microscopic technology to analyze dental wear-patterns, researchers have reconstructed the diets of two species of early humans. Prehistoric Bones Point to First Modern-Human Settlement in Europe Bones found more than a century ago in what is now the Czech Republic represent the earliest human settlement in Europe, new research confirms. Neandertals, Hyenas Fought for Caves, Food, Study Says The discovery of a 41,000-year-old leg bone in a cave in France has opened new questions about how Neandertal humans lived and moved through Europe. Neandertal Advance: First Fully Jointed Skeleton Built Scientists have for the first time constructed a fully articulated Neandertal skeleton using castings from real Neandertal bones. Neandertals Beaten by Rivals' Word Skills, Study Says Neandertals may have died out like a bad movie—by word of mouth. Modern humans' complex use of language sounded the defeat of their big-browed cousins, a new study says. New Fossils Help Piece Together Human Origins Unearthed with rhino, giraffe, monkey, hippo, and antelope remains, fossil fragments are adding detail to the earliest chapters of human evolution. Oldest Human Fossils Identified Were Early Humans and Cave Bears Trading Spaces? Neandertals and cave bears had the same taste in real estate, but the two species never shared a home, new research reveals. What Was "Lucy"? Fast Facts on an Early Human Ancestor Get the basics on the first known Australopithecus afarensis: why she's important, how a pop song provided her name, and whether she's really the mother of "Lucy's baby" |
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