By NATALIE ANGIER Among the Ache hunter-gatherers in eastern Paraguay, healthy adults with no dependent offspring are expected to donate as much as 70 to 90 percent of the food they forage to the needier members of the group. And as those strapping suppliers themselves fall ill, give birth or grow old, they know they can count on the tribe to provide. Among the !Kung bushmen of the Kalahari in Africa, a successful hunter who may be inclined to swagger is kept in check by his compatriots through a ritualized game called “insulting the meat.” You asked us out here to help you carry that pitiful carcass? What is it, some kind of rabbit? Among the Hadza foragers of northern Tanzania, people confronted by a stingy food sharer do not simply accept what’s offered. They hold out their hand, according to Frank Marlowe, an anthropologist at Durham University in England, “encouraging the giver to keep giving until the giver finally draws the line.” Among America’s top executives today, according to a study commissioned by The New York Times, the average annual salary is about $10 million and rising some 12 percent a year. At the same time, the rest of the tribe of the United States of America struggles with miserably high unemployment, stagnant wages and the worst economic crisis since the Great Depression. Now, maybe the wealth gap is a temporary problem, and shiny new quarters will soon rain down on us all. But if you’re feeling tetchy and surly about the lavished haves when you have not a job, if you’re tempted to go out and insult a piece of corporate meat, researchers who study the nature and evolution of human social organization say they are hardly surprised. © 2011 The New York Times Company

Keyword: Evolution
Link ID: 15529 - Posted: 07.05.2011

By KAY E. HOLEKAMP After nine months trapped behind my desk in Michigan, I’m finally back in the African bush, the one place I love above all others on earth. Only here are the skies so vast you can see both rainbows and bright sunshine while sitting under a drenching downpour from a massive black thunderhead. Only here can you be sure to see some weird and interesting form of animal life no matter where you look. Ever heard of a duiker? A solifugid? A pangolin? A springhare? A cameroptera? They all live here, along with hundreds of other animal species. Elephants forage in the riverbed that runs beside our camp, hippos chuckle in the pool below my tent, the shrill calls of white-browed robin-chats tell me when I have overslept, baboons steal our sugar jar whenever one of us is dumb enough to leave it unattended, and giraffes browse silently through camp after dark like great ships drifting in the night. But the best thing about the African bush is that it is where you can find spotted hyenas. As I have done every spring since I joined the faculty in the department of zoology at Michigan State University, I’ve once again traded sitting through endless committee meetings and grading overwhelming stacks of student papers for life in a tented camp where my most pressing concern every day is whether or not I will encounter a grumpy hippo on the footpath connecting my sleeping tent to our lab tent and dining area. © 2011 The New York Times Company

Keyword: Evolution; Sexual Behavior
Link ID: 15466 - Posted: 06.21.2011

By John Matson Does junior really have his father's nose? A common bit of parenting folklore holds that babies tend to look more like their fathers than their mothers, a claim with a reasonable evolutionary explanation. Fathers, after all, do not share a mother's certainty that a baby is theirs, and are more likely to invest whatever resources they have in their own offspring. Human evolution, then, could have favored children that resemble their fathers, at least early on, as a way of confirming paternity. The paternal-resemblance hypothesis got some scientific backing in 1995, when a study in Nature by Nicholas Christenfeld and Emily Hill of the University of California, San Diego, showed that people were much better at matching photos of one-year-old children with pictures of their fathers than with photos of their mothers. (Scientific American is part of Nature Publishing Group.) Case closed? Hardly. "It's a very sexy result, it's seductive, it's what evolutionary psychology would predict—and I think it's wrong," says psychologist Robert French of the National Center for Scientific Research in France. A subsequent body of research, building over the years in the journal Evolution & Human Behavior, has delivered results in conflict with the 1995 paper, indicating that young children resemble both parents equally. Some studies have even found that newborns tend to resemble their mothers more than their fathers. © 2011 Scientific American,

Keyword: Evolution; Sexual Behavior
Link ID: 15459 - Posted: 06.20.2011

by Caroline Williams Octopuses' astonishing mental skills might help us unearth the roots of intelligence – but first we need to understand what makes them so smart BETTY the octopus is curled up in her den, eyes half-closed and clutching a piece of red Lego like a child with a teddy bear. She is, says Kerry Perkins, cephalopod researcher at the Sea Life aquarium in Brighton, UK, much better behaved than some of the octopuses she has worked with. One used to short-circuit a light in its tank by squirting water at it, and would do so whenever the bulb was left on at night. Another made a bid for freedom via the aquarium drainage system, which it seemed to know headed straight out to sea. "Any octopus tank worth its salt has a way of stopping the octopus from escaping," Perkins says as she adds two weights to the lid of Betty's tank. "They love to explore." Aristotle once took this kind of curiosity as a sign that octopuses are stupid - after all, he pointed out, just waving your hands in their direction brings them close enough to catch. We now know that it is just one example of how smart they are. Between them, cephalopods, which also include squids, cuttlefish and nautiluses, can navigate a maze, use tools, mimic other species, learn from each other and solve complex problems. If the latest analyses are to be believed, these skills might show a rudimentary form of consciousness. Cephalopods are the only invertebrates that can boast anything like this kind of mental prowess, and some of their more impressive tricks are shared with only the cleverest vertebrates, such as chimps, dolphins and crows. Yet they evolved along a completely separate path, from snail-like ancestors, and their brains look completely alien to our own (see "A brain apart"). © Copyright Reed Business Information Ltd.

Keyword: Evolution; Intelligence
Link ID: 15431 - Posted: 06.14.2011

By Tina Hesman Saey Bad news for fans of the X-Men: It may take longer to create a new class of mutant superhumans than previous estimates suggested. The first direct measurements of human mutation rates reveal that the speed at which successive generations accumulate single-letter genetic changes is much slower than previously thought. The study, published online June 12 in Nature Genetics, also shows that some individuals mutate faster than others. That means it may be fairly common for people to inherit a disproportionate share of mutations from one parent. Researchers from an international collaboration known as the 1000 Genomes Project deciphered the genetic blueprints of six people from two families — a mother, father and child from each — and counted up the mutations inherited by each child. From there, the team calculated the human mutation rate. “We all mutate,” says study coauthor Philip Awadalla, a population geneticist at the University of Montreal. “And the mutation rate can be extraordinarily variable from individual to individual.” Combined with the results of three similar recent studies, the rate indicates that, on average, about one DNA chemical letter in every 85 million gets mutated per generation through copying mistakes made during sperm and egg production. The new rate means each child inherits somewhere in the neighborhood of 30 to 50 new mutations. © Society for Science & the Public 2000 - 2011

Keyword: Evolution; Genes & Behavior
Link ID: 15430 - Posted: 06.14.2011

By Bruce Bower Way back in the day, females came from far away and males didn’t stray — not far, anyway. That’s the implication, with apologies to Dr. Seuss, of a new study of members of two ancient species in the human evolutionary family. Adult females in both hominid lineages often moved from the places where they were born to distant locations, presumably to find mates among unrelated males, say anthropologist Sandi Copeland of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and her colleagues. Most males in both hominid species spent their entire lives in a home region that covered no more than about 28 square kilometers, or about half the area of Manhattan, Copeland’s team proposes in the June 2 Nature. These ancient “home boys” might have occasionally gone further afield, exploiting resources along wooded areas atop bands of bedrock that extend about 30 kilometers in opposite directions from the South African cave sites where the fossils were found. It’s not clear how far females traveled to reach new groups, only that they did not grow up where they died. “We have the first direct glimpse of early hominids’ geographic movements,” Copeland says. “Ranging differences between males and females were surprising.” © Society for Science & the Public 2000 - 2011

Keyword: Evolution; Sexual Behavior
Link ID: 15389 - Posted: 06.02.2011

By SEAN B. CARROLL I am not a big fan of reality TV, but I will confess that I am a loyal viewer of the Discovery Channel’s “Deadliest Catch” series. The show chronicles the adventures of the crews of several crabbing boats of the Alaskan fleet as they pursue red king crabs on the Bering Sea. What fascinates me, and I suspect other viewers, is the vicarious experience of watching the crews working for long stretches in unimaginable conditions. I know that this landlubber would not last an hour on any boat as it heaved in 30-foot seas, let alone while hauling 800-pound crab pots on an ice-covered deck, in 60-mile-an-hour winds, for 20 to 30 hours straight. That’s definitely not for me. My crab-catching is limited to plucking hermit crabs the size of golf balls off the sands of some quiet Florida beach in 80-degree weather. One might think that not only is there no comparison between my beachcombing and the dangerous business of Alaska crab fishing, but that the two kinds of crabs involved have very little in common. The typically diminutive hermit crabs have to contort their bodies into abandoned snail shells, while the four- to nine-pound red king crabs, the largest of the more than 100 species of king crabs, freely prowl the ocean bottom in search of worms, clams, mussels, starfish and other prey. Looking at those monsters of the deep, safely steamed on your plate at Red Lobster, one might think that such tasty beauties would be more closely related to other crabs on the menu, like stone crabs, than to the largely inedible hermit crabs. © 2011 The New York Times Company

Keyword: Evolution
Link ID: 15355 - Posted: 05.24.2011

Sperm whales speak in distinct regional dialects that appear closely linked to different "cultural groups," a Canadian researcher says. "The animals in the Caribbean sound different than the animals in the Pacific — even the Gulf of Mexico, which is right beside the Caribbean," said Shane Gero, a researcher at Dalhousie University in Halifax. "In a lot of ways, that's very similar to us. We can identify someone from the U.K. versus Canada because they say 'lorry' and not 'truck.'" Sperm whales from many different regions meet in some "multicultural" areas of the ocean but tend to associate with whales that speak their own dialect, Gero told CBC's Quirks & Quarks in an interview that airs Saturday. "Their society really is divided based on culture," he said. "Animals that have different dialects behave differently. They feed on different things. They raise their babies differently." Gero has been studying sperm whales in the Caribbean for his PhD thesis. He and his collaborators in Canada and Scotland have been trying to decode sperm whale language by recording the voices of pairs of animals talking to one another and noting differences among the sounds they make. Female sperm whales spend all year in family groups in subtropical regions of the ocean, while males roam all over the world. When two whales encounter each other, they make patterns of clicks called codas. © CBC 2011

Keyword: Animal Communication; Evolution
Link ID: 15353 - Posted: 05.21.2011

By Adam Summers If you’ve ever chased a cat that’s trying to avoid a bath, you have every right to conclude that, for our size, we humans are pretty poor runners. But chasing a cat is sprinting. Where we excel is endurance running. Moreover, we run long distances at fast speeds: many joggers do a mile in seven-and-a-half minutes, and top male marathoners can string five-minute miles together for more than two hours. A quadruped of similar weight, about 150 pounds, prefers to run a mile at a trot, which takes nine-and-a-half minutes, and would have to break into a gallop to keep pace with a good recreational jogger. That same recreational jogger could keep up with the preferred trotting speed of a thousand-pound horse. Good endurance runners are rare among animals. Although humans share the ability with some other groups, such as wolves and dogs, hyenas, wildebeest, and horses, we alone among primates can run long distances with ease. But what evidence can support the idea that endurance running by itself gave early humans an evolutionary advantage, and that it wasn’t just “piggybacking” on our ability to walk? Many traits, after all, are useful for both activities; long legs, for instance, and the long stride they enable, are helpful to walking as well as to running. But running and walking are mechanically different gaits. A walking person, aided by gravity, acts as an inverted pendulum: the hip swings over the planted foot. In contrast, a runner bounces along, aided by tendons and ligaments that act as springs, which alternately store and release energy. © 2008–2011 Natural History Magazine, Inc

Keyword: Evolution
Link ID: 15331 - Posted: 05.16.2011

Ewen Callaway The first humans to reach Europe may have found it a ghost world. Carbon-dated Neanderthal remains from the foothills of the Caucasus Mountains suggest that the archaic species had died out before modern humans arrived. The remains are almost 10,000 years older than expected. They come from just one cave in western Russia, called Mezmaiskaya, but bones at other Neanderthal sites farther west could also turn out to be more ancient than previously thought, thanks to a precise carbon-dating technique, says Thomas Higham, a palaeoanthropologist at the University of Oxford, UK, and a co-author of a study published this week in the Proceedings of the National Academy of Sciences1. The implication, says Higham's team, is that Neanderthals and humans might never have met in Europe. However, the Neanderthal genome, decoded last year2, hints that the ancestors of all humans, except those from Africa, interbred with Neanderthals somewhere. Perhaps humans departing Africa encountered resident Neanderthals in the Middle East. "DNA results show that there was admixture probably at some stage in our human ancestry, but it more than likely happened quite a long time before humans arrived in Europe," says Ron Pinhasi, an archaeologist at University College Cork in Ireland, who is lead author of the latest study. "I don't believe there were regions where Neanderthals were living next to modern humans. I just don't find it very feasible," he adds. © 2011 Nature Publishing Group,

Keyword: Evolution
Link ID: 15316 - Posted: 05.10.2011

Matt Kaplan Modern mammals often live in groups, but most marsupials are solitary. With no fossil evidence to suggest that the animals have ever behaved otherwise, palaeontologists have long assumed that marsupials have been loners throughout their evolutionary history. This notion is now being overturned by the analysis of a fossil site containing many marsupials that seem to have been living together. The site, in the Tiupampa locality of Bolivia, contains 35 specimens of Pucadelphys andinus, a primitive opossum from the early Palaeocene Epoch (64 million years ago). Teeth are usually all that palaeontologists can find of ancient mammals, because dentition is built to endure punishment, and fossilizes well. However, 22 of the 35 specimens at the Bolivian site consist of teeth, skulls and body skeletons in near-perfect shape. Sandrine Ladevèze, a palaeontologist at the Royal Belgian Institute of Natural Sciences in Brussels, and her colleagues publish an analysis of the specimens today in Nature1. "To find a sample of this quality is almost unheard of," says Richard Cifelli, a palaeontologist at the University of Oklahoma in Norman. Full house But it is not the condition, but the placement of the specimens at the fossil site that intrigued Ladevèze. © 2011 Nature Publishing Group

Keyword: Evolution
Link ID: 15304 - Posted: 05.09.2011

Lucas Laursen Nuclear accidents can have devastating consequences for the people and animals living in the vicinity of the damaged power plants, but they also give researchers a unique opportunity to study the effects of radiation on populations that would be impossible to recreate in the lab. Tim Mousseau, who directs the Chernobyl Research Initiative at the University of South Carolina in Columbia, together with an international team, is studying the long-term ecological and health consequences of the 1986 accident at the Chernobyl nuclear power plant in the Ukraine. Mousseau has been studying Chernobyl since 1998 and his latest work, carried out with colleagues in France and published in Oecologia last month, finds that bird species with orange feathers living in the fallout zone seem to be more susceptible to radiation than their drabber gray and black fellows1. They suggest that production of the more colourful pigments consumes antioxidant molecules that would otherwise confer protection against radiation damage, and that this molecular trade-off is shaping bird populations around the former nuclear power plant. One of the team, Anders Møller from the Pierre and Marie Curie University in Paris, donned a radiation-protection suit to make four bird-watching trips between 2006 and 2009 to the Red Forest and other locations around Chernobyl. In a 2007 analysis of the data from the first bird counts made in spring 2006, Mousseau and Møller found that birds whose feathers were coloured with bright yellow and red carotenoid-based pigments showed a decline in abundance as radiation levels increased, though there was no comparable correlation for bird species with melanin-based colouring, such as brown, black and reddish-brown2. The new study takes the analysis a step further by teasing out the different protective effects of different types of melanin pigment. © 2011 Nature Publishing Group,

Keyword: Evolution
Link ID: 15293 - Posted: 05.05.2011

By Jennifer Viegas The brainier a bird is, the better its chances are of thriving in a city, according to a new study that found many big-brained birds can succeed in urban environments. "Big" in this case refers to brain size relative to body size. In other words, the larger the ratio of brain to body, the more likely the bird will thrive in an urban environment. "Species with relatively larger brains tend to have broader diets, live in diverse habitats and have a higher propensity for behavioral innovations in foraging," lead author Alexei Maklakov told Discovery News. "They are better able to establish viable populations when introduced to new habitats by humans." Maklakov, a researcher in the Department of Animal Ecology at Uppsala University, and his colleagues studied how well -- or not -- 82 species of passerine birds belonging to 22 avian families did in and around a dozen cities in France and Switzerland. Bird species that were able to breed in city centers were considered successful colonizers. Birds that bred around the cities, but not in the urban regions themselves, were considered to be urban avoiders. For the study, which is published in the latest issue of Royal Society Biology Letters, the scientists also looked at the brain size and body mass of each bird. The researchers determined that the following are brainy birds that do well in cities: the great tit, the blue tit, the carrion crow, the jackdaw, the magpie, the nuthatch, the wren, the long-tailed tit and more. Pigeons are not passerines, so these ubiquitous urban dwellers were not included in the study. © 2011 Discovery Communications, LLC.

Keyword: Intelligence; Evolution
Link ID: 15271 - Posted: 04.28.2011

By Daniel Strain Fire ants know how to survive when the waters rise: They turn their bodies into life rafts. A new study explores the physics that keeps fire ant lifeboats, waterborne colonies sometimes containing tens of thousands of bugs, afloat. Linked together, the ants can form a watertight seal that keeps them from drowning, engineers from the Georgia Institute of Technology in Atlanta report the week of April 25 in the Proceedings of the National Academy of Sciences. And the whole is bigger than the sum of its parts, says Julia Parrish, a zoologist at the University of Washington in Seattle: "The properties the group displays are not necessarily predictable by just looking at one individual." Fire ants (Solenopsis invicta), an invasive species around much of the globe, are well-prepared for disaster. When their Brazilian homes flood, entire colonies — including queens, workers and workers carrying larvae — take to the sea. "They have to stay together as a colony to survive," says study coauthor Nathan Mlot of Georgia Tech. Their double-decked rafts — about half the ants float on the bottom holding the rest up — can bob along for days or even weeks. The ants' seafaring success comes down to both small and big properties. On the small scale, single ants can walk on water, at least to a degree, similar to a floating pin or a water-striding insect. When wet, fire ants can also capture tiny air bubbles, probably thanks to the thin layers of hair covering their bodies, giving these intrepid mariners added buoyancy. © Society for Science & the Public 2000 - 2011

Keyword: Miscellaneous
Link ID: 15264 - Posted: 04.26.2011

By Bruce Bower MINNEAPOLIS — Orangutans swim about as well as they fly, but research on three Indonesian islands shows that these long-limbed apes nonetheless catch and eat fish. Orangutans living in Borneo scavenge fish that wash up along the shore and scoop catfish out of small ponds for fresh meals, anthropologist Anne Russon of York University in Toronto reported on April 14 at a meeting of the American Association of Physical Anthropologists. Over two years, Russon saw several animals on these forested islands learn on their own to jab at catfish with sticks, so that the panicked prey would flop out of ponds and into a red ape’s waiting hands. “If orangutans can do this, then early hominids could also have practiced tool-assisted fishing,” Russon said. Although orangutans usually fished alone, Russon observed pairs of apes catching catfish on a few occasions. In one case, an orangutan cringed and pulled away as its companion extracted a fish from a pond. Russon suspects that the onlooker was learning — or at least trying to learn — how to nab aquatic snacks. Observations of fishing by orangutans raise the likelihood that hominids ate meat, including fish, before the emergence of the Homo genus around 2.5 million years ago (SN: 9/11/10, p. 8), said anthropologist David Braun of the University of Cape Town in South Africa. Anthropologists have traditionally held that meat-eating first assumed prominence among early Homo species and fueled brain expansion. © Society for Science & the Public 2000 - 2011

Keyword: Evolution
Link ID: 15220 - Posted: 04.16.2011

By Jennifer Viegas A human skull dated to about 2,684 years ago with an "exceptionally preserved" human brain still inside of it was recently discovered in a waterlogged U.K. pit, according to a new Journal of Archaeological Science study. The brain is the oldest known intact human brain from Europe and Asia, according to the authors, who also believe it's one of the best-preserved ancient brains in the world. "The early Iron Age skull belonged to a man, probably in his thirties," lead author Sonia O'Connor told Discovery News. "Cause of death is rarely possible to determine in archaeological remains, but in this case, damage to the neck vertebrae is consistent with a hanging." "The head was then carefully severed from the neck using a small blade, such as a knife," added O'Connor, a post-doctoral research associate at the University of Bradford. "This was used to cut through the throat and between the vertebrae and has left a cluster of fine cut marks on the bone." The brain-containing skull was found at Heslington, Yorkshire, in the United Kingdom. O'Connor and her team suspect the site served a ceremonial function that persisted from the Bronze Age through the early Roman period. Many pits at the site were marked with single stakes. The remains of the man were without a body, but the scientists also found the headless body of a red deer that had been deposited into a channel. © 2011 Discovery Communications, LLC.

Keyword: Evolution
Link ID: 15186 - Posted: 04.07.2011

by Rebecca Kessler Killer whales living off Antarctica have come up with an ingenious and deadly seal-hunting maneuver. After locating a seal loafing on an ice floe, groups of whales rush the floe, their tails pumping in sync to generate a wave that washes the seal into the water. If at first they don't succeed, the whales return relentlessly to deliver a barrage of waves—and they'll even reposition the ice floe or break it up to improve their odds of success. Once the hapless seal is in the water, the whales gang up to hunt it down, confusing it by blowing swarms of bubbles at it and dragging it below by its hind flippers until it's exhausted and drowns. Then, off they carry their catch to dismember it with remarkable precision and share it. Researchers from the National Oceanic and Atmospheric Administration's Southwest Fisheries Science Center in San Diego, California, describe 22 wave-washing attacks in Marine Mammal Science. Only five instances of wave-washing had previously been documented, and researchers had presumed it uncommon. But the new paper reports that wave-washing appears to be the main hunting tactic of a group of whales the authors call "pack ice killer whales"—and is probably unique to them. In fact, it may be a defining feature of this group. In a 2010 paper, the authors and colleaguesdescribed genetic evidence suggesting that there are at least three distinct species of killer whales rather than just one, as had been supposed. Pack ice killer whales belong to one of the proposed new species. These photographs show the pack ice killer whales' distinctive hunting behavior: how they spot a seal, how they wash it into the sea, and evidence of their extraordinary butchery. (Warning: Some images are graphic.) © 2010 American Association for the Advancement of Science.

Keyword: Evolution; Intelligence
Link ID: 15175 - Posted: 04.05.2011

By Victoria Gill Old World monkeys have better numerical skills than previously thought, researchers have discovered. In a basic numeracy test, long-tailed macaques were able to work out which of two plates contained more raisins. Strangely, they only excelled in this test if they were not allowed to eat the raisins they were shown. The scientists report in the journal Nature Communications that the animals have the ability to understand the concept of relative quantities. The team of researchers from the German Primate Center in Goettingen initially tested the macaques by showing them two plates containing different numbers of raisins. When the animals spontaneously pointed to one of the plates, they were fed the raisins. But in this test, the monkeys often got it wrong - choosing the smaller amount. Lead researcher Vanessa Schmitt said that this was because, rather than thinking about quantities, the animals were thinking about how much they wanted to eat the raisins. "This impulsiveness impaired their judgement," Ms Schmitt told BBC News. BBC © MMXI

Keyword: Intelligence; Evolution
Link ID: 15164 - Posted: 04.02.2011

EAST LANSING, Mich.—When it comes to producing more offspring, larger female hyenas outdo their smaller counterparts. A new study by Michigan State University researchers, which appears in Proceedings of the Royal Society, revealed this as well as defined a new way to measure spotted hyenas’ size. “This is the first study of its kind that provides an estimate of lifetime selection on a large carnivore,” said MSU graduate student Eli Swanson, who published the paper with MSU faculty members Ian Dworkin and Kay Holekamp, all members of the BEACON Center for the Study of Evolution in Action. “In short, we were able to document that larger female hyenas have more cubs over their lifetime than do smaller females as well as develop a novel approach for estimating body size.” Size can be one of the most important traits affecting an animal’s life. It influences eating, getting eaten, speed and agility, and attractiveness to potential mates. However, overall height and weight measurements may not capture differences in more specific traits like leg length that might be more important in survival. To identify the most-important traits, researchers sedated hyenas in Kenya and took 13 measurements on each subject, including total body length, skull size and leg length. They found that while overall size didn’t affect reproductive success, some clusters of traits did. They also learned that the length of the lower leg, the height at the shoulder and body length were all individually associated with more reproductive success. © 2011 U.S.News & World Report LP

Keyword: Evolution; Sexual Behavior
Link ID: 15149 - Posted: 03.29.2011

by Andy Coghlan The molecules that fuel thinking and memory have evolved far more in human brains compared with other primates. Philipp Khaitovich of the Partner Institute for Computational Biology in Shanghai, China, and colleagues analysed brain tissue from deceased humans, chimpanzees and rhesus macaques to study the concentrations of 100 chemicals linked with metabolism. In the human prefrontal cortex, the levels of 24 of these were drastically different from levels in the corresponding brain regions of the other primates. In the cerebellum, however, there were far fewer differences between humans and the other animals, with just six chemicals showing different concentrations. This suggests that, since our lineage split off from other primates, the evolution of metabolism in the thinking and learning parts of our brains has gone much further than in our "primitive" cerebellum. Khaitovich says the comparison confirms the key role played in human thought by glutamate, a chemical that energises brain cells and ferries messages between them. It was present at relatively low levels in humans, which he says is because it is used faster in energy-hungry human brains. "Brain metabolism probably played an important role in evolution of human cognition," Khaitovich says, "and one of the potentially most important changes was in glutamate metabolism." © Copyright Reed Business Information Ltd.

Keyword: Evolution; Attention
Link ID: 15147 - Posted: 03.29.2011