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by Carrie Arnold More than a kilometer below the ocean's surface, where the sunless water is inky black, scientists have documented one of nature's most spectacular living light shows. An underwater survey has found that roughly 20% of bottom-dwelling organisms in the Bahamas produce light. Moreover, all of the organisms surveyed by the researchers proved to have visual senses tuned to the wavelengths of light generated by this bioluminescence. The work speaks to the important role self-generated light plays in deep-sea communities, marine biologists say. Bioluminescence has evolved many times in marine species and may help organisms find mates and food or avoid predators. In the middle depths of the ocean—the mesopelagic zone that is located 200 to 1000 meters below the surface—the vast majority of organisms can bioluminesce. Much less was known about bioluminescence in organisms living close to the sea floor. Such benthic organisms are harder to visit or sample and therefore study, says Sönke Johnsen, a marine biologist at Duke University in Durham, North Carolina. With Tamara Frank, a marine biologist at Nova Southeastern University in Florida, and colleagues, Johnsen recently explored four sites in the northern Bahamas in a submersible. The researchers collected the benthic organisms by suctioning them gently into a lightproof box with a vacuum hose. Once back in their shipboard labs, they stimulated bioluminescence in the captured organisms by softly prodding the animals. Those that glowed were tested further to determine the exact wavelength of light emitted. © 2010 American Association for the Advancement of Science

Keyword: Miscellaneous; Aggression
Link ID: 17239 - Posted: 09.10.2012

By Gary Stix Evolutionary psychology has typically tried to identify the piece parts of human cognition shaped by the rigors of natural selection. New questions have arisen in this contentious discipline about what exactly is on that parts list—or whether the list itself really exists. One of the foremost debating points centers on whether the brain consists of a series of Lego-like modules, each one produced from evolutionary adaptations that resulted in mental tools for things like going after Mastodons, forming clans and communicating the daily incidentals related to food, shelter and mating. Another way to think about all this is to invoke the metaphor of a Swiss-Army knife, with each adaptive module the equivalent of a corkscrew, nail clipper or a myriad of cutting implements. The revisionist viewpoint rejects this neat tailoring of mental functioning championed by psychologists like Leda Cosmides and John Tooby. Instead, upstarts trot out the human hand as a replacement analogy for the pocket knife, a single all-purpose implement that can poke, prod, pull and push. A walk through the new thinking on evolutionary psychology appears in the Aug. 5 edition of the Philosophical Transactions of the Royal Society of London B. (The original journal, founded in 1665, was the first anywhere to deal solely with science—and this issue is open to everyone for a download.) The metaphor of the hand, notes Cecilia Heyes of Oxford in an introductory article, alludes to the ability of a limb extension that can “strip the defensive spines from a piece of fruit, making it safe to eat, but in Thai dancing it can also signal the smallest nuances of emotion. The human hand performs with equal facility a vast array of tasks that natural selection did and did not ‘foresee’.” © 2012 Scientific American,

Keyword: Evolution
Link ID: 17218 - Posted: 08.30.2012

by Hannah Krakauer Kanzi the bonobo continues to impress. Not content with learning sign language or making up "words" for things like banana or juice, he now seems capable of making stone tools on a par with the efforts of early humans. Eviatar Nevo of the University of Haifa in Israel and his colleagues sealed food inside a log to mimic marrow locked inside long bones, and watched Kanzi, a 30-year-old male bonobo chimp, try to extract it. While a companion bonobo attempted the problem a handful of times, and succeeded only by smashing the log on the ground, Kanzi took a longer and arguably more sophisticated approach. Both had been taught to knap flint flakes in the 1990s, holding a stone core in one hand and using another as a hammer. Kanzi used the tools he created to come at the log in a variety of ways: inserting sticks into seams in the log, throwing projectiles at it, and employing stone flints as choppers, drills, and scrapers. In the end, he got food out of 24 logs, while his companion managed just two. Perhaps most remarkable about the tools Kanzi created is their resemblance to early hominid tools. Both bonobos made and used tools to obtain food – either by extracting it from logs or by digging it out of the ground. But only Kanzi's met the criteria for both tool groups made by early Homo: wedges and choppers, and scrapers and drills. © Copyright Reed Business Information Ltd.

Keyword: Evolution; Aggression
Link ID: 17191 - Posted: 08.22.2012

By Jason G. Goldman The largest fish in the ocean is the whale shark (Rhincodon typus). This massive, migratory fish can grow up to twelve meters in length, but its enormous mouth is designed to eat the smallest of critters: plankton. While the biggest, the whale shark isn’t the only gigantic filter-feeding shark out there: the basking shark and the megamouth shark also sieve enormous amounts of the tiny organisms from the sea in order to survive. While scientists like Al Dove and Craig McClain (of Deep Sea News) are learning more and more about the basic biology and behavior of these magnificent creatures, other scientists are busy investigating their neuroanatomy. A few years ago, Kara E. Yopak and Lawrence R. Frank from the University of California in San Diego got their hands on two whale shark brains from an aquarium, and put them into an MRI scanner. But they weren’t just interested in imaging the brains of the whale sharks. What they wanted to know was how the organization of whale shark brains compared to the brains of other shark species for which scientists had previously obtained neuroanatomical data. Would the brains of two species be more similar if they shared a recent evolutionary ancestor, and were therefore more genetically related? Or would shark brains be more similar among species that shared a similar lifestyle, such as those that patrol the middle and surface of the water column (pelagic sharks, such as the great white, oceanic whitetip, blue, mako, and whale sharks) versus those that live along the sea floor (benthic sharks, such as the nurse and cat sharks). Or perhaps the brains of sharks would be grouped according to their habitat, such as those that live in coastal waters, around reefs, or in the open ocean. Maybe sharks brains ought to be grouped according to behavioral specialization, such as hunting methods. Answers to these questions could shed some important light on brain evolution, both in sharks as well as more generally. © 2012 Scientific American

Keyword: Evolution; Aggression
Link ID: 17180 - Posted: 08.18.2012

By Bruce Bower An ancient finger bone recently landed a genetic sucker punch on scientists studying human evolution. DNA extracted from this tiny fossil, unearthed in Siberia’s Denisova Cave, unveiled a humanlike population that interbred with people in East Asia at least 44,000 years ago. Denisovans supplied nearly 5 percent of the genes of native groups now living in Australia, New Guinea and on several nearby islands. That molecular shocker followed a revelation that the genetic instruction books of people from Australia to the Americas contain a roughly 2.5 percent contribution from Neandertals, modern humans’ evolutionary cousins that died out around 30,000 years ago. Pulling the DNA shades up on ancient human dalliances with Neandertals and closely related Denisovans has sparked a scientific consensus that members of mobile human groups interbred with closely related populations in the Homo genus during the Stone Age. “The question is no longer ‘When did ancient populations such as Neandertals go extinct?’ but ‘What happened to those populations and to modern humans as a result of interbreeding?’ ” says anthropologist John Hawks of the University of Wisconsin–Madison. Clear signs of interbreeding have left archaeologists and other students of the Stone Age scrambling to revisit existing ideas about Homo sapiens’ evolutionary past. A dominant theory holding that humans evolved in Africa and left on neat one-way routes to Asia and Europe has to be revised. Instead, these ancient people must have followed a tangled web of paths taking them to other continents and sometimes reversing course. During these travels, humans encountered Neandertals, Denisovans and probably other humanlike populations that were already traipsing interconnected avenues through Asia and Europe. © Society for Science & the Public 2000 - 2012

Keyword: Evolution
Link ID: 17161 - Posted: 08.14.2012

By Stephanie Pappas Senior Writer Parrots can draw conclusions about where to find a food reward not only from clues as to its location, but also from the absence of clues — an ability previously only seen in humans and other apes. In a new study, researchers tested African Grey parrots on their reasoning abilities by shaking empty boxes and boxes filled with food so that the parrots could hear the snacks rattling around. To pick the box that would win them a treat, the parrots had to figure out that the sound indicated food and that a lack of sound from one box probably meant food in the other. It's a challenge that even human children can't reason through until about age 3. "It suggests that Grey parrots have some understanding of causality and that they can use this to reason about the world," study scientist Christian Schloegl, a researcher at the University of Vienna, told LiveScience. African Grey parrots are known to be clever, as are many other birds. In earlier studies with Grey parrots, researchers have shown them two opaque boxes, one full of food and one empty. When the parrots are shown that one box has no food in it, they almost always pick the second box in search of a treat. This could be because the parrots infer that if one box is empty, the other is likely full, Schloegl said. But researchers couldn't rule out that they were simply avoiding the empty box for some unknown reason. © 2012 NBCNews.com

Keyword: Intelligence; Aggression
Link ID: 17142 - Posted: 08.08.2012

By Michael Harré As humans, we aren't born with formidable armaments or defenses, nor are we the strongest, fastest, or biggest species, yet despite this we are amazingly successful. For a long time it was thought that this success was because our enlarged brains allows each of us to be smarter than our competitors: better at abstract thinking, better with tools and better at adapting our behavior to those of our prey and predators. But are these really the most significant skills our brains provide us with? Another possibility is that we are successful because we can form long-lasting relationships with many others in diverse and flexible ways, and that this, combined with our native intelligence, explains why homo sapiens came to dominate the planet. In every way from teaching our young to the industrial division of labour we are a massively co-operative species that relies on larger and more diverse networks of relationships than any other species. In 1992 British anthropologist Robin Dunbar published an article showing that, in primates, the ratio of the size of the neo-cortex to that of the rest of the brain consistently increases with increasing social group size. For example, the Tamarin monkey has a brain size ratio of about 2.3 and an average social group of size of about 5 members. On the other hand, a Macaque monkey has a brain size ratio of around 3.8 but a very large average group size of about 40 members. From this work Dunbar put forward what is now known as the “social brain hypothesis.” The relative size of the neo-cortex rose as social groups became larger in order to maintain the complex set of relationships necessary for stable co-existence. Most famously, Dunbar suggested that given the human brain ratio we have an expected social group size of around 150 people, about the size of what Dunbar called a “clan.” © 2012 Scientific American,

Keyword: Evolution
Link ID: 17141 - Posted: 08.08.2012

By Tina Hesman Saey Expeditions to Africa may have brought back evidence of a hitherto unknown branch in the human family tree. But this time the evidence wasn’t unearthed by digging in the dirt. It was found in the DNA of hunter-gatherer people living in Cameroon and Tanzania. Buried in the genetic blueprints of 15 people, researchers found the genetic signature of a sister species that branched off the human family tree at about the same time that Neandertals did. This lineage probably remained isolated from the one that produced modern humans for a long time, but its DNA jumped into the Homo sapiens gene pool through interbreeding with modern humans during the same era that other modern humans and Neandertals were mixing in the Middle East, researchers report in the August 3 Cell. The evidence for ancient interbreeding is surprisingly convincing, says Richard “Ed” Green, a genome biologist at the University of California, Santa Cruz. “There is a signal that demands explanation, and archaic admixture seems to be the most reasonable one at this point,” he says. Scientists have discovered that some people with ancestry outside Africa have DNA inherited from Neandertals or Denisovans, a mysterious group known only through DNA derived from a fossil finger bone found in a Siberian cave (SN: 6/5/10, p. 5; SN: 1/15/11, p.10). But those researchers had DNA from fossils to guide their research. This time, researchers led by Sarah Tishkoff at the University of Pennsylvania in Philadelphia didn’t have fossil DNA, or even fossils. © Society for Science & the Public 2000 - 2012

Keyword: Evolution
Link ID: 17112 - Posted: 08.01.2012

By JOHN NOBLE WILFORD In the widening search for the origins of modern human evolution, genes and fossils converge on Africa about 200,000 years ago as the where and when of the first skulls and bones that are strikingly similar to ours. So this appears to be the beginning of anatomically modern Homo sapiens. But evidence for the emergence of behaviorally modern humans is murkier — and controversial. Recent discoveries establish that the Homo sapiens groups who arrived in Europe some 45,000 years ago had already attained the self-awareness, creativity and technology of early modern people. Did this behavior come from Africa after gradual development, or was it an abrupt transition through some profound evolutionary transformation, perhaps caused by hard-to-prove changes in communication by language? Now, the two schools of thought are clashing again, over new research showing that occupants of Border Cave in southern Africa, who were ancestors of the San Bushmen hunter-gatherers in the area today, were already engaged in relatively modern behavior at least 44,000 years ago, twice as long ago as previously thought. Two teams of scientists reported these findings Monday in the journal Proceedings of the National Academy of Sciences. Since this early date for the San culture is close to when modern humans first left Africa and reached Europe, proponents of the abrupt-change hypothesis took the findings as good news. Richard G. Klein, a paleoanthropologist at Stanford University, said in an e-mail from South Africa that the new evidence “supports my view that fully modern hunter-gatherers emerged in Africa abruptly around 50,000 years ago, and I remain convinced that the behavior shift, or advance, underlies the successful expansion of modern Africans to Eurasia.” © 2012 The New York Times Company

Keyword: Evolution
Link ID: 17108 - Posted: 07.31.2012

Matt Kaplan Neanderthals have long been viewed as meat-eaters. The vision of them as inflexible carnivores has even been used to suggest that they went extinct around 25,000 years ago as a result of food scarcity, whereas omnivorous humans were able to survive. But evidence is mounting that plants were important to Neanderthal diets — and now a study reveals that those plants were roasted, and may have been used medicinally. The finding comes from the El Sidrón Cave in northern Spain, where the roughly 50,000-year-old skeletal remains of at least 13 Neanderthals (Homo neanderthalensis) have been discovered. Many of these individuals had calcified layers of plaque on their teeth. Karen Hardy, an anthropologist at the Autonomous University of Barcelona in Spain, wondered whether it might be possible to use this plaque to take a closer look at the Neanderthal menu. Using plaque to work out the diets of ancient animals is not entirely new, but Hardy has gone further by looking for organic compounds in the plaque. To do this she and a team including Stephen Buckley, an archaeological chemist at the University of York, UK, used gas chromatography and mass spectrometry to analyse the plaque collected from ten teeth belonging to five Neanderthal individuals from the cave. The plaque contained a range of carbohydrates and starch granules, hinting that the Neanderthals had consumed a variety of plant species. By contrast, there were few lipids or proteins from meat. © 2012 Nature Publishing Group

Keyword: Evolution
Link ID: 17067 - Posted: 07.19.2012

Emma Marris Large-brained animals may be less likely to go extinct in a changing world, perhaps because they can use their greater intelligence to adapt their behaviour to new conditions, according to an analysis presented to a meeting of conservation biologists this week. The finding hints at a way to prioritize future conservation efforts for endangered species. Brain size relative to body size is fairly predictable across all mammals, says Eric Abelson, who studies biological sciences at Stanford University in Palo Alto, California. “As body size grows, brain size grows too, but at slower rate,” he says. Plotting brain size against body size creates a tidy curve. But some species have bigger or smaller brains than the curve would predict for their body size. And a bigger brain-to-body-size ratio usually means a smarter animal. Abelson looked at the sizes of such deviations from the curve and their relationships to the fates of two groups of mammalian species — ‘palaeo’ and ‘modern’. The palaeo group contained 229 species in the order Carnivora from the last 40 million years, about half of which are already extinct. The modern group contained 147 species of North American mammals across 6 orders. Analysis of each group produced similar results: species that weighed less than 10 kilograms and had big brains for their body size were less likely to have gone extinct or be placed on the International Union for Conservation of Nature red list for endangered species. For species larger than about 10 kilograms, the advantage of having a large brain seems to be swamped by the disadvantage of being big. Large species tend to reproduce later in life, have fewer offspring, require more resources and larger territories, and catch the attention of humans, either as food or as predators. Hunting pressure or reductions in available space can hit them particularly hard. © 2012 Nature Publishing Group

Keyword: Evolution
Link ID: 17063 - Posted: 07.18.2012

By JOHN NOBLE WILFORD Who are we, and where did we come from? Scientists studying the origin of modern humans, Homo sapiens, keep reaching deeper in time to answer those questions — toward the last common ancestor of great apes and humans, then forward to the emergence of people more and more like us in body and behavior. Their research is advancing on three fronts. Fossils of skulls and bones expose anatomical changes. Genetics reveals the timing and place of the Eve of modern humans. And archaeology turns up ancient artifacts reflecting abstract and creative thought, and a growing self-awareness. Just last month, researchers made the startling announcement that Stone Age paintings in Spanish caves were much older than previously thought, from a time when Neanderthals were still alive. To help make sense of this cascade of new information, a leading authority on modern human evolution — the British paleoanthropologist Chris Stringer — recently sat for an interview in New York that ranged across many recent developments: the evidence of interbreeding between Neanderthals and Homo sapiens; the puzzling extinct species of little people nicknamed the hobbits; and the implications of a girl’s 40,000-year-old pinkie finger found in a Siberian cave. Dr. Stringer, an animated man of 64, is an anthropologist at the Natural History Museum in London and a fellow of the Royal Society. But he belies the image of a don: He showed up for our interview wearing a T-shirt and jeans, looking as if he had just come in from the field. © 2012 The New York Times Company

Keyword: Evolution
Link ID: 17051 - Posted: 07.17.2012

by Elizabeth Pennisi OTTAWA—With big brains comes big intelligence, or so the hypothesis goes. But there may be trade-offs as well. Humans and other creatures with large brains relative to their body size tend to have smaller guts and possibly fewer offspring. Scientists have debated for decades whether the two phenomena are related. Now a team of researchers says that they are—and that big brains do indeed make us smart. The finding comes thanks to an unusual experiment reported here yesterday at the Evolution Ottawa evolutionary biology meeting in which scientists shrank and grew the brains of guppies over several generations. "This is a real experimental result," says David Reznick, an evolutionary biologist at the University of California, Riverside, who was not involved in the study. "The earlier results were just correlations." Researchers first began to gather evidence that big brains were advantageous after 19th century U.S. biologist Hermon Bumpus examined the brains of sparrows, some of whom had succumbed in a blizzard and some of whom survived. The survivors had relatively larger brains. More recently, evolutionary biologist Alexei Maklakov from Uppsala University in Sweden found evidence that songbirds that colonize cities tend to have larger brains relative to their body size than species still confined to the countryside. The challenge of urban life might require bigger brains, he and his colleagues concluded last year in Biology Letters. Yet in humans and in certain electric fish, larger brain size seems to have trade-offs: smaller guts and fewer offspring. That's led some scientists to suggest there are constraints on how big brains can become because they are expensive to build and maintain. © 2010 American Association for the Advancement of Science.

Keyword: Evolution; Aggression
Link ID: 17026 - Posted: 07.11.2012

by Michael Slezak Evolutionary biologists have a problem with sex in difficult places. Earth's complex and varied environments should, in theory, offer asexual species advantages over their sexual counterparts, says Matthew Goddard at the University of Auckland in New Zealand. An asexual species should adapt more quickly to a specific niche in the environment than a sexual species, because gene mixing between sexual individuals from different niches will produce maladapted hybrids that will not reliably pass on useful adaptations. "All else being equal, the sexual populations should be outcompeted by asexual populations," says Goddard. But the evidence around us suggests that this doesn't actually happen: environmental niches are almost always far more complex than the simple set-ups used in most lab experiments, and yet sexual species abound. To get a clearer idea of what is going on, Goddard and his Auckland colleague, Jeremy Gray, turned to yeast, single-celled organisms that can reproduce sexually or asexually. Goddard and Gray created two environments for the yeast in their lab – one containing relatively little carbon at an uncomfortably hot 37 °C, the other limited for nitrogen instead, at a less stressful 30 °C but with an "osmotic stress" caused by an unusual balance of salts. The researchers then placed sexual and asexual populations in both environments. © Copyright Reed Business Information Ltd.

Keyword: Sexual Behavior; Aggression
Link ID: 17007 - Posted: 07.07.2012

SETH BORENSTEIN, AP Science Writer WASHINGTON (AP) — The more we study animals, the less special we seem. Baboons can distinguish between written words and gibberish. Monkeys seem to be able to do multiplication. Apes can delay instant gratification longer than a human child can. They plan ahead. They make war and peace. They show empathy. They share. "It's not a question of whether they think — it's how they think," says Duke University scientist Brian Hare. Now scientists wonder if apes are capable of thinking about what other apes are thinking. The evidence that animals are more intelligent and more social than we thought seems to grow each year, especially when it comes to primates. It's an increasingly hot scientific field with the number of ape and monkey cognition studies doubling in recent years, often with better technology and neuroscience paving the way to unusual discoveries. This month scientists mapping the DNA of the bonobo ape found that, like the chimp, bonobos are only 1.3 percent different from humans. Says Josep Call, director of the primate research center at the Max Planck Institute in Germany: "Every year we discover things that we thought they could not do." Call says one of his recent more surprising studies showed that apes can set goals and follow through with them. © 2012 Hearst Communications Inc.

Keyword: Evolution; Aggression
Link ID: 16961 - Posted: 06.25.2012

By Jason G. Goldman Yogi Bear always claimed that he was smarter than the average bear, but the average bear appears to be smarter than once thought. Psychologists Jennifer Vonk of Oakland University and Michael J. Beran of Georgia State University have taken a testing methodology commonly used for primates and shown not only that the methodology can be more widely used, but also that bears can distinguish among differing numerosities. Numerical cognition is perhaps the best understood of the core building blocks of the mind. Decades of research have provided evidence for the numerical abilities of gorillas, chimpanzees, rhesus, capuchin, and squirrel monkeys, lemurs, dolphins, elephants, birds, and fish. Pre-linguistic human infants share the same mental modules for representing and understanding numbers as those non-human animal species. Each of these species is able to precisely count sets of objects up to three, but after that, they can only approximate the number of items in a set. Even human adults living in cultures whose languages have not developed an explicit count list must rely on approximation rather than precision for quantities larger than three. For this reason, it is easier for infants and animals to distinguish thirty from sixty than it is to distinguish thirty from forty, since the 1:2 ratio (30:60) is smaller than the 3:4 ratio (30:40). As the ratios increase, the difference between the two sets becomes smaller, making it more difficult to discriminate between them without explicit counting. Given that species as divergent as humans and mosquitofish represent number in the same ways, subject to the same (quantity-based and ratio-based) limits and constraints, it stands to reason that the ability to distinguish among two quantities is evolutionarily-ancient. © 2012 Scientific American

Keyword: Intelligence; Aggression
Link ID: 16949 - Posted: 06.21.2012

Daniel H. Geschwind & Genevieve Konopka The decoding of the human and chimpanzee genomes was heralded as an opportunity to truly understand how changes in DNA resulted in the evolution of our cognitive features. However, more than a decade and much detective work later, the functional consequences of such changes have proved elusive, with a few exceptions1, 2. Now, writing in Cell, Dennis et al.3 and Charrier et al.4 describe the evolutionary history and function of the human gene SRGAP2 and provide evidence for molecular and cellular mechanisms that may link the gene's evolution with that of our brain. It was already known that SRGAP2 is involved in brain development5 and that humans have at least three similar copies of the gene, whereas non-human primates carry only one6. However, the study of duplicated, or very similar, segments of DNA is hampered by the fact that most human cells carry two sets of chromosomes (one inherited from each parent), which makes it difficult to distinguish duplicated copies from the different parental forms of the gene. To circumvent this problem, Dennis et al.3 searched for copies of SRGAP2 in the genome of a hydatidiform mole — an abnormal, non-viable human embryo that results from the fusion of a sperm with an egg that has lost its genetic material; it therefore has chromosomes derived from a single parent. The authors showed that humans carry four non-identical copies (named A–D) of SRGAP2 at different locations on chromosome 1. By comparing the genes' sequences with that of the SRGAP2 gene from the orang-utan and chimpanzee, the authors estimated that SRGAP2 was duplicated in the human lineage about 3.4 million years ago, resulting in SRGAP2A (the ancestral version that we share with other primates) and SRGAP2B. Further duplications of SRGAP2B gave rise to SRGAP2C about 2.4 million years ago and to SRGAP2D about 1 million years ago (Fig. 1a). © 2012 Nature Publishing Group

Keyword: Genes & Behavior; Aggression
Link ID: 16945 - Posted: 06.21.2012

by Michael Balter The basic questions about early European cave art—who made it and whether they developed artistic talent swiftly or slowly—were thought by many researchers to have been settled long ago: Modern humans made the paintings, crafting brilliant artworks almost as soon as they entered Europe from Africa. Now dating experts working in Spain, using a technique relatively new to archaeology, have pushed dates for the earliest cave art back some 4000 years to at least 41,000 years ago*, raising the possibility that the artists were Neandertals rather than modern humans. And a few researchers say that the study argues for the slow development of artistic skill over tens of thousands of years. Figuring out the age of cave art is fraught with difficulties. Radiocarbon dating has long been the method of choice, but it is restricted to organic materials such as bone and charcoal. When such materials are lying on a cave floor near art on the cave wall, archaeologists have to make many assumptions before concluding that they are contemporary. Questions have even arisen in cases like the superb renditions of horses, rhinos, and other animals in France's Grotte Chauvet, the cave where researchers have directly radiocarbon dated artworks executed in charcoal to 37,000 years ago. Other archaeologists have argued that artists could have entered Chauvet much later and picked up charcoal that had been lying around for thousands of years. Now in a paper published online today in Science, applied a technique called uranium-series (U-series) dating to artworks from 11 Spanish caves. U-series dating has been around since the 1950s and is often used to date caves, corals, and other proxies for climate and sea level changes. But it has been used only a few times before on cave art, including by Pike and Pettit, who used it to date the United Kingdom's oldest known cave art at Cresswell Crags in England. © 2010 American Association for the Advancement of Science.

Keyword: Evolution
Link ID: 16919 - Posted: 06.16.2012

by Ann Gibbons Chimpanzees now have to share the distinction of being our closest living relative in the animal kingdom. An international team of researchers has sequenced the genome of the bonobo for the first time, confirming that it shares the same percentage of its DNA with us as chimps do. The team also found some small but tantalizing differences in the genomes of the three species—differences that may explain how bonobos and chimpanzees don't look or act like us even though we share about 99% of our DNA. "We're so closely related genetically, yet our behavior is so different," says team member and computational biologist Janet Kelso of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. "This will allow us to look for the genetic basis of what makes modern humans different from both bonobos and chimpanzees." Ever since researchers sequenced the chimp genome in 2005, they have known that humans share about 99% of our DNA with chimpanzees, making them our closest living relatives. But there are actually two species of chimpanzees that are this closely related to humans: bonobos (Pan paniscus) and the common chimpanzee (Pan troglodytes). This has prompted researchers to speculate whether the ancestor of humans, chimpanzees, and bonobos looked and acted more like a bonobo, a chimpanzee, or something else—and how all three species have evolved differently since the ancestor of humans split with the common ancestor of bonobos and chimps between 5 million and 7 million years ago in Africa. © 2010 American Association for the Advancement of Science.

Keyword: Evolution
Link ID: 16913 - Posted: 06.14.2012

By JAMES GORMAN The extremes of animal behavior can be a source of endless astonishment. Books have been written about insect sex. The antics of dogs and cats are sometimes hard to believe. And birds, those amazing birds: They build elaborate nests, learn lyrical songs, migrate impossibly long distances. But “Gifts of the Crow,” by John N. Marzluff and Tony Angell, includes a description of one behavior that even Aesop never imagined. “On Kinkazan Island in northern Japan,” the authors write, “jungle crows pick up deer feces — dry pellets of dung — and deftly wedge them in the deer’s ears.” What!? I checked the notes at the back of the book, and this account comes from another book, written in Japanese. So I can’t give any more information on this astonishing claim, other than to say that Dr. Marzluff, of the University of Washington, and Mr. Angell, an artist and observer of birds, think that the crows do it in the spirit of fun. Deer droppings, it must be said, are only one of the crows’ gifts. The authors’ real focus is on the way that crows can give us “the ephemeral and profound connection to nature that many people crave.” To that end, however, they tell some wild anecdotes and make some surprising assertions. Many of the behaviors they describe — crows drinking beer and coffee, whistling and calling dogs and presenting gifts to people who feed them — are based on personal testimony and would seem to fall into the category of anecdote rather than science. © 2012 The New York Times Company

Keyword: Intelligence; Aggression
Link ID: 16902 - Posted: 06.12.2012