Human evolution

From Dan Garisto at Science News: New genetic evidence instead suggests that wild precursors to sweet potatoes reached Polynesia at least 100,000 years ago — long before humans inhabited the South Pacific islands, researchers report April 12 in Current Biology. If true, it could also challenge the idea that Polynesian seafarers reached the Americas around the 12th century. … The researchers calculated the average rate of genetic change for the plant, determining that the Polynesian sweet potato diverged from its South American cousin at least 100,000 years ago. That suggests the plants, or their seeds, somehow migrated across the ocean on their own, possibly via wind, water or birds. Precedent exists, the authors note. Two other Ipomoea species crossed the Read More ›

From Bruce Bower at ScienceNews: A trio of dogs buried at two ancient human sites in Illinois lived around 10,000 years ago, making them the oldest known domesticated canines in the Americas. Radiocarbon dating of the dogs’ bones shows they were 1,500 years older than thought, zooarchaeologist Angela Perri said April 13 at the annual meeting of the Society for American Archaeology. … An absence of stone tool incisions on the three ancient dogs’ skeletons indicates that they were not killed by people, but died of natural causes before being buried, Perri said. More. Burial of dogs who died from natural causes implies, of course, a level of affection and esteem. See also: A top anthropology finding of year show Read More ›

From ScienceDaily: In a study published this week in Science Advances, an international team of researchers from Arizona State University’s Institute of Human Origins and School of Human Evolution and Social Change, New York University, University of Kent, and the Max Planck Institute for Evolutionary Anthropology found that a simple, straightforward developmental rule — the “patterning cascade” — is powerful enough to explain the massive variability in molar crown configuration over the past 15 million years of ape and human evolution. “Instead of invoking large, complicated scenarios to explain the majors shifts in molar evolution during the course of hominin origins, we found that simple adjustments and alterations to this one developmental rule can account for most of those changes,” Read More ›

From George Dvorsky at Gizmodo: Though still technically human and featuring very human-like characteristics, they were shorter, more robust, and physically stronger. But they also featured distinctive faces, with heavy brows, weak chins, a large, forward-projecting face, and a wide nose. Some of these characteristics, such as the brow and chin, were likely acquired from their ancestors, but the other features are so distinctive that paleontologists figure they must’ve evolved for a special reason. New research published today in Proceedings of the Royal Society B suggests this is very much the case, and that Neanderthals acquired a facial structure that made life during the Ice Age more bearable. More. Paper. (paywall) Faces really different from “ours”? One gets the impression Read More ›

From James Gallagher at BBC: Prof Rob Knight, from University of California San Diego, told the BBC: “You’re more microbe than you are human.” Originally it was thought our cells were outnumbered 10 to one. “That’s been refined much closer to one-to-one, so the current estimate is you’re about 43% human if you’re counting up all the cells,” he says.More. Well, if that’s true, human life is not at all what the lectern splinterers claim. See also: If viruses can evolve in parallel in related species… ? and Science fictions series 4: Naturalism and the human mind

From Alex Berezow at ACSH: Do you see yourself as a worthless cockroach contributing to the collapse of human civilization? Probably not, but Stanford biologist Paul Ehrlich thinks precisely that about you. Fifty years ago, he published arguably the worst book ever written, The Population Bomb, which declared that human overpopulation would cause mass starvation. Instead, the Green Revolution (led in part by ACSH co-founder Norman Borlaug) caused global food production to explode, and the world population more than doubled from 3.5 billion in 1968 to 7.6 billion today. … Now, at the age of 85, Dr. Ehrlich still hasn’t let reality change his mind. In fact, he’s doubled down on his apocalyptic prognostications. In an interview with The Guardian, Read More ›

From ScienceDaily: Highly mobile eyebrows that can be used to express a wide range of subtle emotions may have played a crucial role in human survival, new research from the University of York suggests. Like the antlers on a stag, a pronounced brow ridge was a permanent signal of dominance and aggression in our early ancestors, which modern humans traded in for a smooth forehead with more visible, hairy eyebrows capable of a greater range of movement. Mobile eyebrows gave us the communication skills to establish large, social networks; in particular to express more nuanced emotions such as recognition and sympathy, allowing for greater understanding and cooperation between people. The study contributes to a long-running academic debate about why other Read More ›

But isn’t the big story about why so many people thought it would be any different? From human paleontologists James Ohman and Asier Gomez-Olivencia at The Conversation: But despite this harsh life of the hunter gatherer, our research indicates that some Neanderthals lived to be fairly old and even had some of the signs of age related illnesses – such as degenerative lesions in the spine, consistent with osteoarthritis. Our research also found that an adult male Neanderthal survived bone fractures. And when he died, he was buried by members of his group. … Denis Peyrony, the director of the excavation when La Ferrassie 1 was found, indicated that this individual was lying in a “funeral pit”, a purposefully dug Read More ›

From Ewen Callaway at Nature: A study analysing genome-wide data from 170 ancient Europeans, including 100 associated with Bell Beaker-style artefacts, suggested that the people who had built the barrow and buried their dead there had all but vanished by 2000 BC. The genetic ancestry of Neolithic Britons, according to the study, was almost entirely displaced. Yet somehow the new arrivals carried on with many of the Britons’ traditions. “That didn’t fit for me,” says Carlin, who has been struggling to reconcile his research with the DNA findings. More. Maybe the later Britons learned something from their predecessors? Or is that not an allowed assumption any more?

From Andrew Porterfield at the Genetic Literacy Project: idea called “genetic load” was developed in the 1930s by famed biologist J.B.S. Haldane, referring to any genome that had increasing numbers of deleterious mutations. The more mutations in a population, the more likely that members of that population couldn’t survive, ultimately threatening the fitness of that population. With enough mutations, a group couldn’t adapt as well to environments, and members would die off. Thus, there’s a limit to natural selection. Now, for some evolutionary biologists, the concept of genetic load has resurfaced as a genuine concern. … He doesn’t think it’s that big a concern. One problem is that modern sequencing has produced much more data, and shown us so many Read More ›

From Denyse O’Leary (O’Leary for News) at MercatorNet: In the early 2000s, one brainwave was to reclassify humans and chimpanzees so as to appear in the same biological category. Chimpanzees would be classified with modern humans and extinct humans such as Neanderthals instead: The common chimpanzee, Pan troglodytes, would be reclassified as Homo troglodytes, just as modern humans are Homo sapiens. The researchers were open about the philosophical and political implications of their proposal: “challenging our long-held view of the boundary between humans and other animals.” Humans, they agreed, “appear as only slightly remodeled chimpanzee-like apes.” The obvious problem is, no matter how one tries to classify and reclassify the problem, chimpanzees simply do not do what humans do. The Read More ›

From Walter Myers III at ENST: While much of the DNA code may be the same, the parts that are not the same have significant differences. The programs I described above, such as Facebook, Instagram, or Snapchat, have different purposes, yet they all depend on the same OS that consists of tens of millions of lines of code. To be specific, let’s say you are using an iPhone with iOS 11 (the Apple mobile OS) installed. iOS is estimated to take up about 4 GB of space on your iPhone. Facebook takes up about 297 MB. Snapchat is about 137 MB. Instagram is about 85 MB. Respectively, that’s 7.4 percent, 3.4 percent, and 2.1 percent of the size of iOS. Read More ›

From ScienceDaily: The team also compared these Neandertal genomes to the genomes of people living today, and showed that all of the late Neandertals were more similar to the Neandertals that contributed DNA to present-day people living outside Africa than an older Neandertal from Siberia. Intriguingly, even though four of the Neandertals lived at a time when modern humans had already arrived in Europe they do not carry detectable amounts of modern human DNA. “It may be that gene flow was mostly unidirectional, from Neandertals into modern humans,” says Svante Pääbo, Director at the Max Planck Institute for Evolutionary Anthropology. “Our work demonstrates that the generation of genome sequences from a large number of archaic human individuals is now technically Read More ›

From ScienceDaily: Modern humans co-existed and interbred not only with Neanderthals, but also with another species of archaic humans, the mysterious Denisovans. Research now describes how, while developing a new genome-analysis method for comparing whole genomes between modern human and Denisovan populations, researchers unexpectedly discovered two distinct episodes of Denisovan genetic intermixing, or admixing, between the two. This suggests a more diverse genetic history than previously thought between the Denisovans and modern humans. … What is known about Denisovan ancestry comes from a single set of archaic human fossils found in the Altai mountains in Siberia. That individual’s genome was published in 2010, and other researchers quickly identified segments of Denisovan ancestry in several modern-day populations, most significantly with individuals Read More ›

From ScienceDaily: Anthropologists at the Smithsonian’s National Museum of Natural History and an international team of collaborators have discovered that early humans in East Africa had — by about 320,000 years ago — begun trading with distant groups, using color pigments and manufacturing more sophisticated tools than those of the Early Stone Age. These newly discovered activities approximately date to the oldest known fossil record of Homo sapiens and occur tens of thousands of years earlier than previous evidence has shown in eastern Africa. These behaviors, which are characteristic of humans who lived during the Middle Stone Age, replaced technologies and ways of life that had been in place for hundreds of thousands of years. Paper. (paywall) – Richard Potts, Read More ›