What are fingerprints good for, besides aiding police investigations? That’s the question that biomechanics researcher Roland Ennos recently set out to answer. This notion that human fingerprints (and presumably footprints) evolved because they act like tire or boot tread–increasing the friction against a smooth surface so we don’t slip or drop stuff–is a 100-year-old urban myth that, apparently, had never been put to the test [NPR].
To test the impact of fingerprints, Ennos rigged a machine that measured the amount of friction generated by a fingertip (belonging to study coauthor Peter Warman) when it was pressed against a piece of acrylic glass. Warman gradually increased the pressure, going from a light touch on the glass to a tight grip, but the corresponding friction didn’t increase as much as the researchers expected. Soon they realised that the skin was not behaving like a normal solid, where friction is proportional to the strength of the contact. Instead, it was behaving like rubber, where the friction is proportional to the contact area between the two surfaces [BBC News].
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It may sound like a paradox, but a new theory suggests that one of humanity’s most noble instincts, altruism, evolved on bloody battlefields in prehistoric times. Evolutionary biologist Samuel Bowles argues that prehistoric culture may have selected for individuals who behaved altruistically towards other individuals in their social groups. The story begins with the climactic swings that occurred between approximately 10,000 to 150,000 years ago in the late Pleistocene period may have pushed once-isolated bands of hunter-gatherers into more frequent contact with one another…. “I think that’s just a recipe for high-level conflict” [New Scientist], says Bowles.
These conflicts weren’t large-scale pitched battles, Bowles explains. “We’re talking about groups of men who got out in twos or threes or fives,” he says. “They didn’t have a chain of command and it’s hard to see how they could force people to fight.” For this reason, altruistic intent on the part of each warrior is key. Each person would do better to stay home than to put their life on the line for their neighbours – yet they still went out and risked their lives, Bowles says [New Scientist].
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It’s hard to imagine having more fun in the name of science: In a new study, researchers tickled young chimpanzees, bonobos, gorillas, orangutans, and even a few human babies, and recorded the vocalizations that resulted. Primatologist Marina Davila Ross wanted to examine the evolutionary history of laughter, so she and her colleagues recorded the sounds produced when they tickled 22 great apes and 3 human babies, picking the usual sensitive spots: armpits, palms, feet, and necks.
Scientists have known that great apes vocalize when tickled at least since Charles Darwin’s time. But it was unclear whether these sounds were actually related to human laughter. Now, researchers … have concluded that laughter has been evolving in primates over the last 10 to 16 million years, since at least the last common ancestor of humans and modern great apes [Wired.com].
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Researchers have endowed lab mice with the human version of a gene involved in language, and while the mice didn’t exactly sit up and start reciting poetry about cheese, they did show some intriguing differences in both their vocal patterns and brain structure.
Mice have their own form of the gene, called FOXP2, but they and all other animals lack key changes found only in humans and our evolutionary cousins, Neanderthals. Some researchers speculate that these differences may help explain why humans are the only animal able to communicate with complex languages, and not simple grunts, barks or songs [New Scientist]. By tweaking the gene in mice and changing it to the human form, researchers hoped to get a clue as to how our early hominid ancestors were changed by the new form of the gene.
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A small, lemur-like creature may have been an early ancestor of monkeys, apes, and humans. A magnificently preserved fossil dating from 47 million years ago reveals an animal that had, among other things, opposable thumbs, similar to humans’ and unlike those found on other modern mammals. It has fingernails instead of claws. And scientists say they believe there is evidence it was able to walk on its hind legs [ABC News].
In a study that will be published in the journal PLoS ONE tomorrow, researchers will report that this extraordinary fossil could be a “stem group” from which higher primates evolved, “but we are not advocating this” [The New York Times]. The fossil was first discovered in 1983 in the Messel Shale Pit, an old quarry near Frankfurt, Germany that has long been a World Heritage Site because of its rich fossil beds. The specimen was excavated by private collectors but was then divided into two parts and sold; it was only two years ago that scientists reassembled the complete fossil and began studying it.
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Early humans and Neanderthals may have clashed violently during their brief coexistence in Europe, a new study suggests, and humans may have either eaten their Neanderthal opponents or taken their teeth as trophies. Anthropologist Fernando Rozzi and his colleagues conducted a new analysis of a jawbone found in a cave in southwest France. They say that the jawbone probably belonged to a Neanderthal, and that it shows cut marks similar to those found on reindeer that were butchered by early humans.
Rozzi believes that the jawbone was cut in the process of removing flesh and the tongue, a technique also used on the deer that early humans frequently fed on. He believes this proves that Neanderthals were fair game for human consumption, too. “Neanderthals met a violent end at our hands and in some cases we ate them,” Rozzi said…. “For years, people have tried to hide away from the evidence of cannibalism, but I think we have to accept it took place,” he added [The Guardian]. But his theory is likely to provoke intense argument from other researchers, who believe that humans and Neanderthals had little interaction.
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The latest evidence that the ancient Indonesian “hobbit” was a distinct species of hominid, and not just a deformed pygmy, comes from the soles of its feet. Ever since researchers discovered the fossils of a three-foot-tall hominid with a chimpanzee-sized brain on the Indonesian island of Flores, debate has raged over how to interpret the bones. Now, a new study supports the theory that the hobbit, Homo floresiensis, was a species that split from our human lineage early in evolutionary history, and developed its strange shape in the isolation of the island. Other experts agree that evidence is accumulating that H. floresiensis was, in fact, a bona fide species.
In the new study, published in Nature, researchers found that the hobbit’s foot was surprisingly long in relation to the body, and that it had other ape-like features. The navicular bone, which helps form the arch in the modern foot, was especially primitive, more akin to one in great apes. Without a strong arch — that is, flat-footed — the hominid would have lacked the springlike action needed for efficient running. It could walk, but not run like humans. Weighing the new evidence, the research team led by William L. Jungers … concluded that “the foot of H. floresiensis exhibits a broad array of primitive features that are not seen in modern humans of any body size” [The New York Times].
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When the earliest human ancestors left the trees and struck out to make a new life for themselves on the ground, there was no going back, a new study suggests. Researchers examined the ankle bones of those early people and compared them to those of chimpanzees, and say that by 4 million years ago the proto-humans were no longer adapted for skillful tree climbing.
Researchers estimate that the chimpanzee and human lineages split about 5 million to 7 million years ago. Yet experts are divided about what happened next to the first hominins, as members of the human subfamily are called. One group argues–based on evidence that early members of the human line lived in woodland environments and had curved fingers and toes that were good for climbing–that the first hominins spent some time in the trees even as they adapted to their new ground-dwelling lifestyle [ScienceNOW Daily News]. The other faction believes that when humans began to walk upright they quickly lost their arboreal ways, and argues that their arms and legs were more human-like than ape-like.
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The oldest known fossil of a human child with a skull deformity has been discovered, suggesting that early humans did not kill or abandon their abnormal offspring, as has been commonly assumed. A research team reconstructed the 530,000-year-old skull, the first pieces of which were unearthed in Spain in 2001, and determined that the child likely suffered from craniosynostosis, a debilitating genetic disorder in which some pieces of the skull fuse too quickly, causing pressure to build in the brain [Wired] and interfering with brain development. The severity of the deformity is not clear, but researchers say the child probably had learning difficulties and other mental health issues, and certainly would have required extra care.
The child belonged to the species Homo heidelbergensis, who lived in Europe 800,000 years ago and may have been the direct ancestors of Neanderthals. Humans are thought to be unique in the way they care for sick individuals. Researchers call it conspecific care, but most laypeople would probably call it compassion. Other primates don’t display similar behavior, so we know humans evolved the ability at some point, even if scientists can’t quite pinpoint when. The work could mean that humans as far back as half a million years ago had differentiated from our primate ancestors [Wired].
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Isolated people living in the remote mountains of Cameroon have provided evidence that emotions expressed in Western music are universally recognizable, researchers say. In a new study, researchers found that members of the Mafa tribe could pick out happy, sad, and fearful tunes, despite having no exposure to Western music. Most likely the Mafa were picking up on the same “tone of voice” cues used in human speech, said study team member Stefan Koelsch…. “Western music mimics the emotional features of human speech, using the same melodic and rhythmic structures,” Koelsch said [National Geographic News].
Researchers say the Mafa’s ability to parse the emotions expressed in instrumental classical, jazz, and rock music adds evidence to the theory that music played some role in human evolution. Researchers have proposed numerous hypotheses about why humans make music, ranging from emotional communication to group solidarity. Other scientists, such as Harvard University linguist Steven Pinker, have countered that music is just “auditory cheesecake” with no real evolutionary significance. If music is the result of Darwinian selection, it’s likely that all members of the human species, regardless of their culture, will respond to it in similar ways [ScienceNOW Daily News].
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A clever and painstaking new analysis has revealed that the famous Homo erectus fossil known as Peking Man is 200,000 years older than previously thought. The fossil, discovered almost a century ago during excavations of the Zhoukoudian caves near Beijing, is now thought to be about 750,000 years old. The revised date could change the timeline and number of migrations of the Homo erectus species out of Africa and into Asia [LiveScience].
Homo erectus were the first hominids to leave the evolutionary cradle of Africa. The species had a distinctive barrel-shaped torso and stood [57 to 70 inches] tall, walking upright in a similar way to modern humans [Nature News]. Researchers had previously suggested that one wave of Homo erectus wayfarers migrated out of Africa between 2 million and 1.6 million years ago, settling Indonesia and southern Asia first before moving northward. But new fossil discoveries, coupled with the new dating of Peking Man, are forcing paleoanthropologists to rethink this scenario.
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A top official at Turkey’s science agency reportedly forced the editors of its science magazine to remove a cover story on the life and work of Charles Darwin in what appears to be a sign of the Turkish government’s official discomfort with the theory of evolution.
The article was stripped from the March issue of the widely read popular-science magazine Bilim ve Teknik (Science and Technology) just before it went to press. The magazine, which is published by Turkey’s research funding and science management organization, TÜBİTAK, also switched a planned cover picture of Darwin for an illustration relating to global warming [Nature News]. The editor of the magazine says she was removed from her post over the incident, but has declined to comment further as she’s still an employee of TUBITAK.
The March issue of the magazine, which was intented to celebrate Darwin’s 200th birthday, reached newsstands a week late and 16 pages short. Once the behind-the-scenes machinations became known, academics reacted with outrage. Turkish writer Ender Helvacıoğlu from Science and Future magazine called on the science community to react against this incident and pressure the government, who has the last word appointing the council’s scientific committee. “This intervention can’t be regarded as solely censorship. It connotes the states rejection of science” [Bianet], he wrote. Today a group of university professors were expected to gather at the science council’s headquarters to call for the resignation of the official who ordered the article removed.
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Researchers have peeked inside the brains of religious people responding to statements about God, and found that there’s no discrete part of the brain that handles religious beliefs–there’s no “God spot,” as other neuroscientists have suggested. The new study found that the neural activity in the subjects’ brains corresponded to brain networks known to have other, nonreligious functions…. “There is nothing segregated or conserved or special about religious beliefs, compared to other belief systems,” [lead researcher Jordan] Grafman said. The networks activated by religious beliefs overlap with those that mediate political beliefs and moral beliefs, he said [The New York Times].
The test subjects were read different types of statements dealing with God and religion while their brains were scanned with an fMRI machine, which measures blood flow to different parts of the brain. The scans showed that religious thoughts “light up” the areas of our brain which have evolved most recently, such as those involved in imagination, memory and “theory of mind” – the recognition that other people and living things can have their own thoughts and intentions [New Scientist].
Some researchers have hypothesized that religious beliefs are a byproduct of the neural networks used in theory of mind, suggesting that humans first evolved to imagine what other people are feeling, even people who aren’t present — and from there it was a short step to positing supernatural beings [Wired].
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About 10 percent of humanity is left-handed (including your humble blogger), but researchers have long wondered why the trait persists, since lefties seem to be at a disadvantage in the evolutionary race. Previous studies have found that lefties have shorter lifespans, shorter stature, and are more likely to be homosexual, three factors that make it more difficult for lefties to attract mates and reproduce. But a new study suggests that in addition to the vaunted creativity of southpaws, lefties may have simply had a tactical advantage throughout human evolution.
The study, which will be published in the Philosophical Transactions of the Royal Society B, surveys the existing literature and weighs the costs and the benefits of being left-handed. The study suggests that lefties have the element of surprise in one-on-one competitions, whether they’re serving tennis balls or attacking their enemies with knives. Study co-author Charlotte Faurie explains that because left-handers are less common, “their opponents will be surprised by the way they fight, and this will provide [lefties] an advantage,” she added. “It’s exactly the same in tennis or in boxing or in any sport where there is face-to-face opposition,” Faurie added [National Geographic News].
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Being treated unfairly in a game triggers the same facial expression as stomach-turning tastes and images, a new study has found, suggesting that the brain mechanism of disgust evolved to help humans avoid not just rotten food, but also immoral behavior.
“Our idea is that morality builds upon an old mental reflex, said study co-author Adam Anderson…. “The brain had already discovered a system for rejecting things that are bad for it. Then it co-opted this and attached it to conditions much removed from something tasting or smelling bad” [Wired News].
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