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By Michael Balter Humans are generally highly cooperative and often impressively altruistic, quicker than any other animal species to help out strangers in need. A new study suggests that our lineage got that way by adopting so-called cooperative breeding: the caring for infants not just by the mother, but also by other members of the family and sometimes even unrelated adults. In addition to helping us get along with others, the advance led to the development of language and complex civilizations, the authors say. Cooperative breeding is not unique to humans. Up to 10% of birds are cooperative breeders, as are meerkats and New World monkeys such as tamarins and marmosets. But our closest primate relatives, great apes such as chimpanzees, are not cooperative breeders. Because the human and chimpanzee lineages split between 5 million and 7 million years ago, and humans are the only apes that engage in cooperative breeding, researchers have puzzled over how this helping behavior might have evolved all over again on the human line. In the late 1990s, Sarah Blaffer Hrdy, now an anthropologist emeritus at the University of California, Davis, proposed the cooperative breeding hypothesis. According to her model, early in their evolution humans added cooperative breeding behaviors to their already existing advanced ape cognition, leading to a powerful combination of smarts and sociality that fueled even bigger brains, the evolution of language, and unprecedented levels of cooperation. Soon after Hrdy’s proposal, anthropologists Carel van Schaik and Judith Burkart of the University of Zurich in Switzerland began to test some of these ideas, demonstrating that cooperatively breeding primates like marmosets engaged in seemingly altruistic behavior by helping other marmosets get food with no immediate reward to themselves. © 2014 American Association for the Advancement of Science.

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 20001 - Posted: 08.27.2014

Ewen Callaway One could be forgiven for mistaking anomalocaridids for creatures from another world. The spade-shaped predators, which lived in the seas during the Cambrian — the geological era stretching from 541 million to 485 million years ago — had eyes that protruded from stalks and a pair of giant appendages on the sides of their mouths. But three stunningly well-preserved fossils found in China now show that the anomalocaridid brain was wired much like that of modern creatures called velvet worms, or onychophorans. Both anomalocaridids and onychophorans belong to the arthropods, the group of invertebrates that includes spiders and insects and whose brain structures come in three main types. Two of those were already known to be very ancient, and the new fossils, described today in Nature1, suggest that the third type — the neural architecture found in onychophorans — also has changed little over more than half a billion years of evolution. Named Lyrarapax unguispinus, the three fossils reveal creatures that — at 8 centimetres long — are on the small side for anomalocaridids, some of which are thought to have been as long as 2 to 3 metres. But the fossils’ segmented bodies and frontal appendages are pure anomalocaridid, says Nicholas Strausfeld, a neuroscientist at the University of Arizona in Tucson, who co-led the study. What really grabbed Strausfeld’s attention was the creature’s brain, preserved flattened like a pressed flower: “I said, ‘Holy shit, that’s an onychophoran brain!’” he recalls. The animal’s frontal appendages are connected to nerve bundles, or ganglia, in front of optic nerves. Both the ganglia and the optic nerves lead to a segmented brain. The layout is an uncanny match to the wiring of the velvet worm’s brain, Strausfeld says: “It’s completely unlike anything else in any other arthropod.” © 2014 Nature Publishing Group

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 19851 - Posted: 07.19.2014

by Colin Barras The Neanderthals knew how to make an entrance: teeth first. Our sister species' distinctive teeth were among the first unique aspects of their anatomy to evolve, according to a study of their ancestors. These early Neanderthals may have used their teeth as a third hand, gripping objects that they then cut with tools. The claim comes from a study of fossils from Sima de los Huesos in northern Spain. This "pit of bones" may be an early burial site, and 28 near-complete skeletons have been pulled from it, along with a large hand-axe that might be a funeral gift. The hominins in the pit look like Neanderthals, but are far too old. That suggests they are forerunners of the Neanderthals, and if that is the case they can tell us how the species evolved. To find out, Juan Luis Arsuaga Ferreras at the UCM-ISCIII Joint Centre for Research into Human Evolution and Behaviour in Madrid, Spain, and colleagues studied 17 of the skulls. They found that the brain case was still the same shape as in older species. But the skulls' protruding faces and small molar teeth were much more Neanderthal-like. This suggests the earliest Neanderthals used their jaws in a specialised way. It's not clear how, but it probably wasn't about food, says Ferreras. "There are no indications of any dietary specialisation in the Neanderthals and their ancestors. They were basically carnivores." © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 19750 - Posted: 06.21.2014

Carl Zimmer All animals do the same thing to the food they eat — they break it down to extract fuel and building blocks for growing new tissue. But the metabolism of one species may be profoundly different from another’s. A sloth will generate just enough energy to hang from a tree, for example, while some birds can convert their food into a flight from Alaska to New Zealand. For decades, scientists have wondered how our metabolism compares to that of other species. It’s been a hard question to tackle, because metabolism is complicated — something that anyone who’s stared at a textbook diagram knows all too well. As we break down our food, we produce thousands of small molecules, some of which we flush out of our bodies and some of which we depend on for our survival. An international team of researchers has now carried out a detailed comparison of metabolism in humans and other mammals. As they report in the journal PLOS Biology, both our brains and our muscles turn out to be unusual, metabolically speaking. And it’s possible that their odd metabolism was part of what made us uniquely human. When scientists first began to study metabolism, they could measure it only in simple ways. They might estimate how many calories an animal burned in a day, for example. If they were feeling particularly ambitious, they might try to estimate how many calories each organ in the animal’s body burned. Those tactics were enough to reveal some striking things about metabolism. Compared with other animals, we humans have ravenous brains. Twenty percent of the calories we take in each day are consumed by our neurons as they send signals to one another. Ten years ago, Philipp Khaitovich of the Max Planck Institute of Evolutionary Anthropology and his colleagues began to study human metabolism in a more detailed way. They started making a catalog of the many molecules produced as we break down food. “We wanted to get as much data as possible, just to see what happened,” said Dr. Khaitovich. To do so, the scientists obtained brain, muscle and kidney tissues from organ donors. They then extracted metabolic compounds like glucose from the samples and measured their concentrations. All told, they measured the levels of over 10,000 different molecules. © 2014 The New York Times Company

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior; Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 19670 - Posted: 05.28.2014

|By Isaac Bédard Very few animals have revealed an ability to consciously think about the future—behaviors such as storing food for the winter are often viewed as a function of instinct. Now a team of anthropologists at the University of Zurich has evidence that wild orangutans have the capacity to perceive the future, prepare for it and communicate those future plans to other orangutans. The researchers observed 15 dominant male orangutans in Sumatra for several years. These males roam through immense swaths of dense jungle, emitting loud yells every couple of hours so that the females they mate with and protect can locate and follow them. The shouts also warn away any lesser males that might be in the vicinity. These vocalizations had been observed by primatologists before, but the new data reveal that the apes' last daily call, an especially long howl, is aimed in the direction they will travel in the morning—and the other apes take note. The females stop moving when they hear this special 80-second call, bed down for the night, and in the morning begin traveling in the direction indicated the evening before. The scientists believe that the dominant apes are planning their route in advance and communicating it to other orangutans in the area. They acknowledge, however, that the dominant males might not intend their long calls to have such an effect on their followers. Karin Isler, a Zurich anthropologist who co-authored the study in PLOS ONE last fall, explains, “We don't know whether the apes are conscious. This planning does not have to be conscious. But it is also more and more difficult to argue that they [do not have] some sort of mind of their own.” © 2014 Scientific American

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior; Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 14: Attention and Consciousness
Link ID: 19635 - Posted: 05.19.2014

By NATALIE ANGIER Of the world’s 43,000 known varieties of spiders, an overwhelming majority are peevish loners: spinning webs, slinging lassos, liquefying prey and attacking trespassers, each spider unto its own. But about 25 arachnid species have swapped the hermit’s hair shirt for a more sociable and cooperative strategy, in which dozens or hundreds of spiders pool their powers to exploit resources that would elude a solo player. And believe it or not, O ye of rolled-up newspaper about to dispatch the poor little Charlotte dangling from your curtain rod for no better reason than your purported “primal fear,” these oddball spider socialites may offer fresh insight into an array of human mysteries: where our personalities come from, why some people can’t open their mouths at a party while others can’t keep theirs shut and, why, no matter our age, we can’t seem to leave high school behind. “It’s very satisfying to me that the most maligned of organisms may have something to tell us about who we are,” said Jonathan N. Pruitt, a biologist at the University of Pittsburgh who studies social spiders. The new work on social spiders is part of the expanding field of animal personality research, which seeks to delineate, quantify and understand the many stylistic differences that have been identified in a vast array of species, including monkeys, minks, bighorn sheep, dumpling squid, zebra finches and spotted hyenas. Animals have been shown to differ, sometimes hugely, on traits like shyness, boldness, aggressiveness and neophobia, or fear of the new. Among the big questions in the field are where those differences come from, and why they exist. Reporting recently in The Proceedings of the Royal Society B, Dr. Pruitt and Kate L. Laskowski, of the Leibniz Institute of Freshwater Ecology and Inland Fisheries in Berlin, have determined that character-building in social spiders is a communal affair. While they quickly display the first glimmerings of a basic predisposition — a relative tendency toward shyness or boldness, tetchiness or docility — that personality is then powerfully influenced by the other spiders in the group. © 2014 The New York Times Company

Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 19598 - Posted: 05.12.2014

by Colin Barras Enough of the cheap jibes: Neanderthals may have been just as clever as modern humans. Anthropologists have already demolished the idea that Neanderthals were dumb brutes, and now a review of the archaeological record suggests they were our equals. Neanderthals were one of the most successful of all hominin species, occupying much of Europe and Asia. Their final demise about 40,000 years ago, shortly after Homo sapiens walked into their territory, is often put down to the superiority of our species. It's time to lay that idea to rest, say Paola Villa at the University of Colorado in Boulder and Wil Roebroeks at Leiden University in the Netherlands. Just as smart as you For instance, there is evidence that Homo sapiens could use fire to chemically transform natural materials into glue 70,000 years ago, but Neanderthals were performing similarly complex chemical syntheses at least 200,000 years ago. And although 70,000-year-old engraved ochre from South Africa is seen as evidence that our species had developed sophisticated symbolism and perhaps even language, similar artefacts have been found at 50,000-year-old Neanderthal sites in Spain. What's more, Neanderthals might have been able to talk. Late last year we learned that our extinct cousins had a hyoid, a small bone in the neck that plays a big role in speech, very like ours. Evidence has even emerged that Homo sapiens may have learned some skills by copying Neanderthals. Yet despite all of this evidence, the idea that Neanderthals were our inferiors still persists. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior; Chapter 19: Language and Hemispheric Asymmetry
Related chapters from MM:Chapter 15: Language and Our Divided Brain
Link ID: 19566 - Posted: 05.04.2014

It looks like a standardized test question: Is the sum of two numbers on the left or the single number on the right larger? Rhesus macaques that have been trained to associate numerical values with symbols can get the answer right, even if they haven’t passed a math class. The finding doesn’t just reveal a hidden talent of the animals—it also helps show how the mammalian brain encodes the values of numbers. Previous research has shown that chimpanzees can add single-digit numbers. But scientists haven’t explained exactly how, in the human or the monkey brain, numbers are being represented or this addition is being carried out. Now, a new study helps begin to answer those questions. Neurobiologist Margaret Livingstone of Harvard Medical School in Boston and her colleagues had already taught three rhesus macaques (Macaca mulatta) in the lab to associate the Arabic numbers 0 through 9 and 15 select letters with the values zero through 25. When given the choice between two symbols, monkeys reliably chose the larger to get a correspondingly larger number of droplets of water, apple juice, or orange soda as a reward. To test whether the monkeys could add these values, the researchers began giving them a choice between a sum and a single symbol rather than two single symbols. Within 4 months, the monkeys had learned how the task worked and were able to effectively add two symbols and compare the sum to a third, single symbol. To ensure that the monkeys hadn’t simply memorized every possible combination of symbols and associated a value with the combination—this wouldn’t be true addition—Livingstone’s team next taught the animals an entirely new set of symbols —Tetris-like blocks rather than letters and numbers. With the new symbols, the monkeys were again able to add—this time calculating the value of combinations they’d never seen before and confirming the ability to do basic addition, the team reports online today in the Proceedings of the National Academy of Sciences. © 2014 American Association for the Advancement of Science.

Related chapters from BP7e: Chapter 18: Attention and Higher Cognition; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 14: Attention and Consciousness
Link ID: 19518 - Posted: 04.22.2014

Claudia Dreifus To Neil H. Shubin’s long résumé — paleontologist, molecular biologist, dean and professor of anatomy at the University of Chicago School of Medicine, best-selling author — can now be added “television host.” Dr. Shubin, 53, who helped discover the 375-million-year-old fish called Tiktaalik, hailed as a missing link between sea and land animals, will preside over “Your Inner Fish,” a three-part series on evolution (based on his book of the same title) that makes its debut Wednesday on PBS. We spoke in Chicago in February and in New York last month. What follows is an edited and condensed version of the conversations. Q. Where did you grow up? A. Suburban Philadelphia. My mom’s a retired nursing home administrator. My father, Seymour Shubin, is a fiction writer. He writes mysteries. My favorite is “The Captain”; it won an Edgar award. He’s an educated man, but science kind of scares him. So when I’m writing, my dad is my target audience. Whenever I hit a tricky scientific concept, I think, “How would I communicate this to him?” This is why my books are written, intentionally, without jargon, which can lead to some gyrations because jargon does have precision. The funny thing is, I’m not sure he always gets what I do. When I first started working on the book version of “Your Inner Fish,” he asked, “Neil, how did you become a scientist?” I thought, “All these years he’s seen me run off to the Arctic, but he’s never been quite sure what I do up there.” So let me ask you his question: How did you become a paleontologist? I was one of those kids with lots of hobbies: astronomy, dinosaurs, collecting rocks, collecting stamps. It all came together when I went to college in New York — Columbia — and volunteered at the American Museum of Natural History. That place was like a playground for me. © 2014 The New York Times Company

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 19466 - Posted: 04.10.2014

Neandertals and modern Europeans had something in common: They were fatheads of the same ilk. A new genetic analysis reveals that our brawny cousins had a number of distinct genes involved in the buildup of certain types of fat in their brains and other tissues—a trait shared by today’s Europeans, but not Asians. Because two-thirds of our brains are built of fatty acids, or lipids, the differences in fat composition between Europeans and Asians might have functional consequences, perhaps in helping them adapt to colder climates or causing metabolic diseases. “This is the first time we have seen differences in lipid concentrations between populations,” says evolutionary biologist Philipp Khaitovich of the CAS-MPG Partner Institute for Computational Biology in Shanghai, China, and the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, lead author of the new study. “How our brains are built differently of lipids might be due to Neandertal DNA.” Ever since researchers at the Max Planck sequenced the genome of Neandertals, including a super high-quality genome of a Neandertal from the Altai Mountains of Siberia in December, researchers have been comparing Neandertal DNA with that of living people. Neandertals, who went extinct 30,000 years ago, interbred with modern humans at least once in the past 60,000 years, probably somewhere in the Middle East. Because the interbreeding happened after moderns left Africa, today’s Africans did not inherit any Neandertal DNA. But living Europeans and Asians have inherited a small amount—1% to 4% on average. So far, scientists have found that different populations of living humans have inherited the Neandertal version of genes that cause diabetes, lupus, and Crohn’s disease; alter immune function; and affect the function of the protein keratin in skin, nails, and hair. © 2014 American Association for the Advancement of Science.

Related chapters from BP7e: Chapter 13: Homeostasis: Active Regulation of the Internal Environment; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 19438 - Posted: 04.02.2014

Ewen Callaway An equine oddity with the head of a zebra and the rump of a donkey, the last quagga (Equus quagga quagga) died in 1883. A century later, researchers published1 around 200 nucleotides sequenced from a 140-year-old piece of quagga muscle. Those scraps of DNA — the first genetic secrets pulled from a long-dead organism — revealed that the quagga was distinct from the mountain zebra (Equus zebra). More significantly, the research showed that from then on, examining fossils would no longer be the only way to probe extinct life. “If the long-term survival of DNA proves to be a general phenomenon,” geneticists Russell Higuchi and Allan Wilson of the University of California, Berkeley, and their colleagues noted in their quagga paper1, “several fields including palaeontology, evolutionary biology, archaeology and forensic science may benefit.” At first, progress was fitful. Concerns over the authenticity of ancient-DNA research fuelled schisms in the field and deep scepticism outside it. But this has faded, thanks to laboratory rigour that borders on paranoia and sequencing techniques that help researchers to identify and exclude contaminating modern DNA. These advances have fostered an ancient-genomics boom. In the past year, researchers have unveiled the two oldest genomes on record: those of a horse that had been buried in Canadian permafrost for around 700,000 years2, and of a roughly 400,000-year-old human relative from a Spanish cavern3. A Neanderthal sequence every bit as complete and accurate as a contemporary human genome has been released4, as has the genome of a Siberian child connecting Native Americans to Europeans5. © 2014 Nature Publishing Group

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory, Learning, and Development
Link ID: 19417 - Posted: 03.27.2014

Why do some humans have lighter skin than others? Researchers have longed chalked up the difference to tens of thousands of years of evolution, with darker skin protecting those who live nearer to the equator from the sun’s intense radiation. But a new study of ancient DNA concludes that European skin color has continued to change over the past 5000 years, suggesting that additional factors, including diet and sexual attraction, may also be at play. Our species, Homo sapiens, first arose in Africa about 200,000 years ago, and researchers assume that its first members were as dark-skinned as Africans are today, because dark skin is advantageous in Africa. Dark skin stems from higher levels of the pigment melanin, which blocks UV light and protects against its dangers, such as DNA damage—which can lead to skin cancer—and the breakdown of vitamin B. On the other hand, skin cells need exposure to a certain amount of UV light in order to produce vitamin D. These competing pressures mean that as early humans moved away from the equator, it makes sense that their skin lightened. Recent research, however, has suggested that the picture is not so simple. For one thing, a number of genes control the synthesis of melanin (which itself comes in two different forms in humans), and each gene appears to have a different evolutionary history. Moreover, humans apparently did not begin to lighten up immediately after they migrated from Africa to Europe beginning about 40,000 years ago. In 2012, for example, a team led by Jorge Rocha, a geneticist at the University of Porto in Portugal, looked at variants of four pigmentation genes in modern Portuguese and African populations and calculated that at least three of them had only been strongly favored by evolution tens of thousands of years after humans left Africa. In January, another team, led by geneticist Carles Lalueza-Fox of the University of Barcelona in Spain, sequenced the genome of an 8000-year-old male hunter-gatherer skeleton from the site of La Braña-Arintero in Spain and found that he was dark rather than light-skinned—again suggesting that natural selection for light skin acted relatively late in prehistory. © 2014 American Association for the Advancement of Science

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 19342 - Posted: 03.11.2014

By PAUL VITELLO Alison Jolly, an American-born primatologist whose research in the forests of Madagascar shed new light on the evolution of social intelligence and helped disprove a longstanding scientific tenet that males were dominant in every primate species, died on Feb. 6 in Lewes, East Sussex, England. She was 76. The cause was breast cancer, said Barbara Orlando, a longtime friend. Dr. Jolly’s two major insights emerged from her 1960s field studies of the lemur, a primate whose development in relative isolation on the island of Madagascar makes the species something akin to a living fossil. Dr. Jolly cited lemurs’ complex social relationships as evidence of an unexplored trail in one of anthropology’s great mysteries: the evolution of higher intelligence. Writing in the journal Science in 1966, she suggested that the many hours lemurs spent in play, mutual grooming and social networking — activities that establish the social ties and hierarchies that determine access to food, mate selection and migration patterns — may have been as important to the evolution of intelligence as the development of weapons and tools of hunting and protection, then considered the hallmarks of evolutionary advance. More unnerving to colleagues was her discovery that in some primate species, females run the show. The finding upended a bedrock assertion in evolutionary biology — based on studies of chimpanzees and orangutans in captivity — that males dominated females in every primate species, including humans. “Females have social, spatial and feeding priority over males,” Dr. Jolly wrote in describing the feeding, mating, child-rearing and recreational habits of the ring-tailed lemur, one of about 100 recognized species of lemur, of which more than a dozen are female-dominant. Among the ring-tailed lemurs, Dr. Jolly wrote in “Lemur Behavior: A Madagascar Field Study,” “all females, whether dominant or subordinate in the female hierarchy, are dominant over males.” © 2014 The New York Times Company

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 8: Hormones and Sex
Link ID: 19265 - Posted: 02.19.2014

By Meeri Kim, Neanderthal genes lurk among us. Small traces of Neanderthal DNA have been confirmed in the areas of the genome that affect skin and hair of modern humans, according to two new studies that also give clues as to which Neanderthal traits may have been helpful — or harmful — to the survival of our species. The studies, published online Wednesday in the journals Nature and Science, came to similar conclusions despite using vastly different methods of genomic analysis. For East Asian and European populations, genes that provide the physical characteristics of skin and hair have a high incidence of Neanderthal DNA — possibly lending toughness and insulation to weather the cold as early man emerged from Africa, the studies conclude. Neanderthals were thought to have already been adapted to a chillier, more northern environment. Perhaps most notably, Neanderthal DNA was not found in genes that influence testicles or the X chromosome, according to the Nature study, hinting that when the Neanderthal ventured outside his species for sex, the introduction of his DNA may have reduced male fertility in early humans. As a result, evolution wiped away the Neanderthal DNA that negatively affected procreation. “There’s strong evidence that when the two met and mixed, they were at the edge of biological compatibility,” said Nature study author and Harvard University geneticist David Reich. “The people who eventually survived and thrived had quite a bit of hurdles to overcome.” This is consistent with what is seen in nature: When two species mate that are sufficiently far away biologically, the resulting hybrids tend to have lowered fertility. Early humans and Neanderthals interbred about 40,000 to 80,000 years ago around the Middle East, during man’s migration out of Africa. © 1996-2014 The Washington Post

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 19188 - Posted: 01.30.2014

by Ashley Yeager Monkeys may have rudimentary brain wiring that later evolved into the connections that gave humans the ability to understand language, think flexibly and make decisions. Brain scans of 25 humans and 25 macaques show that 11 components of the ventrolateral frontal cortex, located behind the temples, were similarly wired in both species. The results suggest that humans did not develop completely new and specialized brain systems for certain types of complex thought, researchers report January 28 in Neuron. The scans also show that macaques do not have the lateral frontal pole, which helps humans with strategic planning, decision-making and multitasking. © Society for Science & the Public 2000 - 2014.

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 19184 - Posted: 01.30.2014

Imagine a couple of million years ago, a curious young alien from the planet Zantar — let's call him a grad student — lands on Earth, looks around and asks, "Who's the brainiest critter on this planet? Relative to body size, who's got the biggest brain?" The answer, back then, would not have been us. (Two million years ago, apes — even walking ones — had much smaller brains.) The brainiest weren't ancestral crows or parrots or magpies or ravens or elephants or colonies of ants or bees or termites. The Earthlings with the biggest brains back then were dolphins (and certain whales). The Zantarian grad student would have wanted to meet them. A visitor from Zantar and a dolphin check each other out. But had the grad student arrived earlier, dolphins wouldn't have been the champs, because evolution is always changing life. , at Emory University in Atlanta, has been studying fossilized brains. And looking back, she sees sudden spurts of brain growth in different animals. "[T]he most dramatic increase in brain-to-body ratio in dolphins and toothed whales occurred 35 million years ago," she tells Chris Impey, the astronomer and writer, in Talking About Life. Something happened to make their medium-sized brains bigger, Lori says, then bigger still. For 20 million years certain dolphin species kept their brains growing until — just as mysteriously as it started — about 15 million years ago, they stopped. Why? Had the dolphins answered some secret dolphin question? Figured out a puzzle? Adapted to an environmental change? Gotten tired? Hit a limit? What? Dolphin says, "Enough." ©2014 NPR

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior; Chapter 1: Biological Psychology: Scope and Outlook
Related chapters from MM:Chapter 1: An Introduction to Brain and Behavior
Link ID: 19131 - Posted: 01.15.2014

Ed Yong A marine iguana (Amblyrhynchus cristatus) at the Galapagos Islands National Park rests calmly as tourists walk by — a behaviour that may have evolved because of a lack of predators. Expand When Charles Darwin visited the Galapagos Islands, he noted that many of its animal inhabitants were so unafraid of people that “a gun is here almost superfluous”. He swatted birds with his hat, pulled the tails of iguanas and sat on giant tortoises. These antics fuelled his famous idea that animals become tame when they live on remote, predator-free islands. Now, William Cooper Jr of Indiana University–Purdue University in Fort Wayne has tested Darwin's hypothesis on 66 species of lizards from around the world and found that island dwellers tended to be more docile than their continental relatives — the strongest evidence yet for this classic idea. The results are published this week in Proceedings of the Royal Society B1. Several studies and unpublished reports have shown that particular species are more approachable on islands where there are fewer predators, or quicker to flee on islands that contain introduced hunters such as feral cats. But despite this largely anecdotal evidence for island tameness, “no one has ever established that it’s a general phenomenon in any group”, says Cooper. “We showed that for a large prey group — lizards — there really is a significant decline in wariness on islands.” © 2014 Nature Publishing Group

Related chapters from BP7e: Chapter 15: Emotions, Aggression, and Stress; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress
Link ID: 19107 - Posted: 01.08.2014

By Melissa Hogenboom Science reporter, BBC News An analysis of a Neanderthal's fossilised hyoid bone - a horseshoe-shaped structure in the neck - suggests the species had the ability to speak. This has been suspected since the 1989 discovery of a Neanderthal hyoid that looks just like a modern human's. But now computer modelling of how it works has shown this bone was also used in a very similar way. Writing in journal Plos One, scientists say its study is "highly suggestive" of complex speech in Neanderthals. The hyoid bone is crucial for speaking as it supports the root of the tongue. In non-human primates, it is not placed in the right position to vocalise like humans. An international team of researchers analysed a fossil Neanderthal throat bone using 3D x-ray imaging and mechanical modelling. This model allowed the group to see how the hyoid behaved in relation to the other surrounding bones. Stephen Wroe, from the University of New England, Armidale, NSW, Australia, said: "We would argue that this is a very significant step forward. It shows that the Kebara 2 hyoid doesn't just look like those of modern humans - it was used in a very similar way." He told BBC News that it not only changed our understanding of Neanderthals, but also of ourselves. "Many would argue that our capacity for speech and language is among the most fundamental of characteristics that make us human. If Neanderthals also had language then they were truly human, too." BBC © 2013

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior; Chapter 19: Language and Hemispheric Asymmetry
Related chapters from MM:Chapter 15: Language and Our Divided Brain
Link ID: 19066 - Posted: 12.24.2013

By JOHN NOBLE WILFORD Early in the 20th century, two brothers discovered a nearly complete Neanderthal skeleton in a pit inside a cave at La Chapelle-aux-Saints, in southwestern France. The discovery raised the possibility that these evolutionary relatives of ours intentionally buried their dead — at least 50,000 years ago, before the arrival of anatomically modern humans in Europe. These and at least 40 subsequent discoveries, a few as far from Europe as Israel and Iraq, appeared to suggest that Neanderthals, long thought of as brutish cave dwellers, actually had complex funeral practices. Yet a significant number of researchers have since objected that the burials were misinterpreted, and might not represent any advance in cognitive and symbolic behavior. Now an international team of scientists is reporting that a 13-year re-examination of the burials at La Chapelle-aux-Saints supports the earlier claims that the burials were intentional. The researchers — archaeologists, geologists and paleoanthropologists — not only studied the skeleton from the original excavations, but found more Neanderthal remains, from two children and an adult. They also studied the bones of other animals in the cave, mainly bison and reindeer, and the geology of the burial pits. The findings, in this week’s issue of Proceedings of the National Academy of Sciences, “buttress claims for complex symbolic behavior among Western European Neanderthals,” the scientists reported. William Rendu, the paper’s lead author and a researcher at the Center for International Research in the Humanities and Social Sciences in New York, said in an interview that the geology of the burial pits “cannot be explained by natural events” and that “there is no sign of weathering and scavenging by animals,” which means the bodies were covered soon after death. © 2013 The New York Times Company

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 19041 - Posted: 12.17.2013

By CARL ZIMMER Scientists have found the oldest DNA evidence yet of humans’ biological history. But instead of neatly clarifying human evolution, the finding is adding new mysteries. In a paper in the journal Nature, scientists reported Wednesday that they had retrieved ancient human DNA from a fossil dating back about 400,000 years, shattering the previous record of 100,000 years. The fossil, a thigh bone found in Spain, had previously seemed to many experts to belong to a forerunner of Neanderthals. But its DNA tells a very different story. It most closely resembles DNA from an enigmatic lineage of humans known as Denisovans. Until now, Denisovans were known only from DNA retrieved from 80,000-year-old remains in Siberia, 4,000 miles east of where the new DNA was found. The mismatch between the anatomical and genetic evidence surprised the scientists, who are now rethinking human evolution over the past few hundred thousand years. It is possible, for example, that there are many extinct human populations that scientists have yet to discover. They might have interbred, swapping DNA. Scientists hope that further studies of extremely ancient human DNA will clarify the mystery. “Right now, we’ve basically generated a big question mark,” said Matthias Meyer, a geneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and a co-author of the new study. Hints at new hidden complexities in the human story came from a 400,000-year-old femur found in a cave in Spain called Sima de los Huesos (“the pit of bones” in Spanish). The scientific team used new methods to extract the ancient DNA from the fossil. “This would not have been possible even a year ago,” said Juan Luis Arsuaga, a paleoanthropologist at Universidad Complutense de Madrid and a co-author of the paper. © 2013 The New York Times Company

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory, Learning, and Development
Link ID: 19001 - Posted: 12.05.2013