Chapter 6. Evolution of the Brain and Behavior

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Links 1 - 20 of 1904

By JAMES GORMAN and CHRISTOPHER WHITWORTH Cockatoos are smart birds, and the Goffin’s cockatoos in a Vienna lab are among the smartest. In an experiment reported about a year ago, they turned out to be real stars at making tools from a variety of materials in order to get a treat. In a new study, researchers tested the birds’ ability to match shapes using an apparatus reminiscent of a child’s toy. The birds had to put a square tile into a square hole and more complicated, asymmetrical shapes into matching holes. If they were successful, they got a treat. Cornelia Habl, a master’s student at the University of Vienna, and Alice M. I. Auersperg, a researcher at the University of Veterinary Medicine in Vienna, ran several experiments. They reported in the journal PLOS One that the cockatoos were not only able to match the shapes to the holes, but did much better than monkeys or chimpanzees. “It was thought to be an exclusively human ability for a long time,” Ms. Habl said. Tests of matching shapes are used to mark milestones in child development. Babies can put a sphere into the right hole at age 1, but they can’t place a cube until age 2. From there, they continue to improve. Some primates can do similar tasks, although they need a lot of basic training to get up to speed before they can use the experimental apparatus, called a key box. The birds jumped right in without any training and excelled. “Compared to primates, the cockatoos performed very well,” Ms. Habl said. Why are they so good? In the wild, they haven’t been observed using tools. But they are generalists, foragers who take whatever food they can find. They are adaptable enough to do well in some urban areas in Australia, Ms. Habl said. To succeed in a variety of environments eating a variety of foods, “they have to be very, very flexible.” © 2017 The New York Times Company

Keyword: Evolution; Intelligence
Link ID: 24344 - Posted: 11.21.2017

By JAMES GORMAN One of the biggest problems in studying animal communication is figuring out whether the animals know what they are doing. A bird may screech and another bird may understand that the screech is a response to danger. But that doesn’t prove the screecher intended to warn others. It might have been a predictable but involuntary response to something scary, like a scream at a horror movie. So scientists spend a lot of time testing animals in ingenious ways to figure out what might be going on. Three scientists testing wild chimpanzees in Uganda reported Wednesday in the journal Science Advances that chimpanzees can do something that previously had only been known in human beings. They change the way they are communicating to take into account what their audience knows. Humans do this all the time. To a fellow baseball fan you might say, “So, there’s a runner on third, one out, bottom of the ninth, and McAfee hits a sac fly.” To someone from another planet, you might say, “There was a really exciting moment in a sporting event I was attending last night.” Or you might just forget it. Catherine Crockford and Roman M. Wittig of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and Klaus Zuberbühler of the University of St. Andrews in Scotland were studying wild chimpanzees in Uganda, so the subject of their communication was snakes, not baseball. When a chimp saw a realistic model of a snake, the animal would make more sounds — called hoos — and make a greater effort to show where the snake was if it seemed that other chimps in the area were unaware of the danger. If it seemed other chimps already knew about the snake, it would make fewer calls and stay a shorter time at the danger. To run the experiment, the researchers put a model snake on a path chimpanzees used. When a chimp came along, before it reached the snake, they would play two different chimp calls — either a “rest hoo” or several “alert hoos.” The rest hoo would be made by a chimp that was resting, not aware of any danger. The alert hoos would indicate the chimp who made it had seen something dangerous, like a snake. So the chimp on the trail would know either that its neighbors were clueless or aware of danger. © 2017 The New York Times Company

Keyword: Consciousness; Evolution
Link ID: 24333 - Posted: 11.16.2017

Mariah Quintanilla Emma Watson, Jake Gyllenhaal, journalist Fiona Bruce and Barack Obama all walk into a sheep pen. No, this isn’t the beginning of a baaa-d joke. By training sheep using pictures of these celebrities, researchers from the University of Cambridge discovered that the animals are able to recognize familiar faces from 2-D images. Given a choice, the sheep picked the familiar celebrity’s face over an unfamiliar face the majority of the time, the researchers report November 8 in Royal Society Open Science. Even when a celeb’s face was slightly tilted rather than face-on, the sheep still picked the image more often than not. That means the sheep were not just memorizing images, demonstrating for the first time that sheep have advanced face-recognition capabilities similar to those of humans and other primates, say neurobiologist Jennifer Morton and her colleagues. Sheep have been known to pick out pictures of individuals in their flock, and even familiar handlers (SN: 10/6/12, p. 20). But it’s been unclear whether the skill was real recognition or simple memorization. Sheep now join other animals, including horses, dogs, rhesus macaques and mockingbirds, that are able to distinguish between individuals of other species. Over a series of four training sessions, the sheep’s ability to choose a familiar face, represented by one of the four celebrities, over a completely unfamiliar face improved. |© Society for Science & the Public 2000 - 2017.

Keyword: Attention; Evolution
Link ID: 24306 - Posted: 11.08.2017

James Gorman Dogs have evolved to be friendly and tolerant of humans and one another, which might suggest they would be good at cooperative tasks. Wolves are known to cooperate in hunting and even in raising one another’s pups, but they can seem pretty intolerant of one another when they are snapping and growling around a kill. So researchers at the Wolf Science Center at the University of Vienna decided to compare the performance of wolves and dogs on a classic behavioral test. To get a food treat, two animals have to pull ropes attached to different ends of a tray. The trick is that they have to pull both ropes at the same time. Chimps, parrots, rooks and elephants have all succeeded at the task. When Sarah Marshall-Pescini, Friederike Range and colleagues put wolves and dogs to the test, wolves did very well and dogs very poorly. In recordings of the experiments, the pairs of wolves look like experts, while the dogs seem, well, adorable and confused. The researchers reported their findings in the Proceedings of the National Academy of Sciences. With no training, five of seven wolf pairs succeeded in mastering the task at least once. Only one of eight dog pairs did. © 2017 The New York Times Company

Keyword: Attention; Evolution
Link ID: 24304 - Posted: 11.08.2017

By James T. Costa One day in May of 1840, a young scientist in London did something that will sound strange to any new parent: He deliberately startled his 4-month-old son, provoking piercing squalls from the baby and probably a baleful glare from his wife. Then he did it again. Darwin remains best known for his world-shaking theories on plant and animal evolution. But people were never far from his mind. The scientist was Charles Darwin, and the experiment on his son Willy turned out to be an often-overlooked landmark in the history of science. Darwin, then just 31 years old, had become a convert to the field of “transmutation,” as evolution was called then, and had experienced an epiphany when he discovered its driver, which he dubbed natural selection. The former theology student immediately grasped the implications of this theory, declaring that the theological interpretation of the natural world had been undone by scientific evidence — “The fabric falls!” as he put it in a notebook. And while Darwin remains best known for his world-shaking theories on plant and animal evolution, as put forward in the 1859 book “On the Origin of Species,” people and society were never far from his mind. Convinced of the evolutionary unity of life, Darwin naturally saw humans as part of the tapestry: They were animals too, after all. (Carl Linnaeus may have been deliberately provocative when, in 1758, he derived the taxonomic name “primates” from the Latin for “prime” or “first rank,” to refer not only to humans but to monkeys and apes; it also happened to be the term applied to bishops.) The standard view of the time was that, despite superficial similarities, there was no true relationship between humans and other primates, let alone other animals. Weren’t we humans clearly endowed with a soul and mental qualities that set us apart from and above the animal kingdom? But Darwin saw deeper significance in the family relationship, one of continuity, common descent. To him, there was no real gap between people and primates — differences, yes, but of degree and not kind. “Origin of man now proved,” he declared in 1838. “He who understands baboon would do more towards metaphysics than Locke.” Copyright 2017 Undark

Keyword: Emotions; Evolution
Link ID: 24291 - Posted: 11.04.2017

Molecular method reveals neuronal basis of brain states – NIH-funded animal study. NIMH-funded scientists revealed the types of neurons supporting alertness, using a molecular method called MultiMAP in transparent larval zebrafish. Multiple types of neurons communicate by secreting the same major chemical messengers: serotonin (red), dopamine and noradrenalin (yellow) and acetylcholine (cyan). Using a molecular method likely to become widely adopted by the field, researchers supported by the National Institutes of Health have discovered brain circuitry essential for alertness, or vigilance – and for brain states more generally. Strikingly, the same cell types and circuits are engaged during alertness in zebra fish and mice, species whose evolutionary forebears parted ways hundreds of millions of years ago. This suggests that the human brain is likely similarly wired for this state critical to survival. “Vigilance gone awry marks states such as mania and those seen in post-traumatic stress disorder and depression,” explained Joshua Gordon, M.D., Ph.D., director of the NIH’s National Institute of Mental Health (NIMH), which along with the National Institute on Drug Abuse, co-funded the study. “Gaining familiarity with the molecular players in a behavior – as this new tool promises – may someday lead to clinical interventions targeting dysfunctional brain states.” For the first time, Multi-MAP makes it possible to see which neurons are activated in a behaving animal during a particular brain state – and subsequently molecularly analyze just those neurons to identify the subtypes and circuits involved.

Keyword: Attention; Evolution
Link ID: 24282 - Posted: 11.03.2017

By KAREN WEINTRAUB In the late 1950s and early 1960s, Jane Goodall started attributing personalities to the chimpanzees she followed in Gombe National Park in what is now Tanzania. In her descriptions, some were more playful or aggressive, affectionate or nurturing. Many scientists at the time were horrified, she recalled. Considered an amateur — she didn’t yet have her Ph.D. — they contended she was inventing personality traits for animals. Dr. Goodall, now 83, said in a phone interview on Monday from her home in England that scientists thought “I was guilty of the worst kind of anthropomorphism.” But time has borne out her insights. Chimpanzees in the wild have personalities similar to those in captivity, and both strongly overlap with traits that are familiar in humans, a new study published in Scientific Data confirms. The new examination of chimpanzees at Gombe updates personality research conducted on 24 animals in 1973 to include more than 100 additional chimps that were evaluated a few years ago. The animals were individually assessed by graduate students in the earlier study, and in the latest by Tanzanian field assistants, on personality traits like agreeableness, extroversion, depression, aggression and self-control. Researchers used different questionnaires to assess the chimps’ traits in the two studies, but most of the personality types were consistent across the two studies. These traits seen among wild chimps matched ones seen among captive animals, the study found, and are similar to those described in people. Dr. Goodall, who is promoting a new documentary, “Jane,” about those early days of her research, said she’s not surprised. She knew from childhood experiences with guinea pigs, tortoises and her favorite dog, Rusty, that animals have personalities that are quite familiar. © 2017 The New York Times Company

Keyword: Evolution; Emotions
Link ID: 24241 - Posted: 10.25.2017

By Ann Gibbons When Neandertals mated with modern humans, they shared more than an intimate moment and their own DNA. They also gave back thousands of ancient African gene variants that Eurasians had lost when their ancestors swept out of Africa in small bands, perhaps 60,000 to 80,000 years ago. Restored to their lineage, this diversity may have been a genetic gift to Eurasian ancestors as they spread around the world. Today, however, some of these African variants are a burden: They seem to boost the risk of becoming addicted to nicotine and having wider waistlines. In talks last week at the annual meeting of The American Society of Human Genetics here, researchers announced that some “Neandertal” genetic variants inherited by modern humans outside of Africa are not peculiarly Neandertal genes, but represent the ancestral human condition. The work highlights just how much diversity was lost when people passed through a genetic bottleneck as they moved out of Africa. “They left many beneficial variants behind in Africa,” says evolutionary genomicist Tony Capra of Vanderbilt University in Nashville, who reported the results. “Interbreeding with Neandertals provided an opportunity to get back some of those variants, albeit with many potentially weakly deleterious Neandertal alleles as well.” His team found the ancient African variants when they scrutinized the genomes of more than 20,000 people in the 1000 Genomes Project and Vanderbilt’s BioVU data bank of electronic health records. They soon noticed a strange pattern: Stretches of chromosomes inherited from Neandertals also carried ancient alleles, or mutations, found in all the Africans they studied, including the Yoruba, Esan, and Mende peoples. © 2017 American Association for the Advancement of Science.

Keyword: Evolution
Link ID: 24232 - Posted: 10.24.2017

Katharina Kropshofer Life is not so different beneath the ocean waves. Bottlenose dolphins use simple tools, orcas call each other by name, and sperm whales talk in local dialects. Many cetaceans live in tight-knit groups and spend a good deal of time at play. That much scientists know. But in a new study, researchers compiled a list of the rich behaviours spotted in 90 different species of dolphins, whales and porpoises, and found that the bigger the species’ brain, the more complex – indeed, the more “human-like” – their lives are likely to be. This suggests that the “cultural brain hypothesis” – the theory that suggests our intelligence developed as a way of coping with large and complex social groups – may apply to whales and dolphins, as well as humans. Writing in the journal, Nature Ecology and Evolution, the researchers claim that complex social and cultural characteristics, such as hunting together, developing regional dialects and learning from observation, are linked to the expansion of the animals’ brains – a process known as encephalisation. The researchers gathered records of dolphins playing with humpback whales, helping fishermen with their catches, and even producing signature whistles for dolphins that are absent – suggesting the animals may even gossip. Another common behaviour was adult animals raising unrelated young. “There is the saying that ‘it takes a village to raise a child’ [and that] seems to be true for both whales and humans,” said Michael Muthukrishna, an economic psychologist and co-author on the study at the London School of Economics. © 2017 Guardian News and Media Limited

Keyword: Evolution
Link ID: 24202 - Posted: 10.17.2017

Carl Safina Last week footage of five young elephants being captured in Zimbabwe to sell to zoos travelled round the world. Parks officials used helicopters to find the elephant families, shot sedatives into the young ones, then hazed away family members who came to the aid of the drugged young ones as they fell. The film, shared exclusively with the Guardian, showed the young captives being trussed up and dragged on to trucks. In the final moments of footage, two men repeatedly kick a small dazed elephant in the head. Removing young elephants from their parents and sending them into captivity is largely justified on the basis that they do not feel and suffer as we do. For decades we have been admonished against anthropomorphism – imbuing animals with human-type emotions such as sadness or love. But, actually, humans have these emotions because other animals do as well. Brain science, evolutionary biology, and behavioural science now show that elephants, humans, and many other animals share a near-identical nervous system and likely experience near-identical basic emotions. Human and elephant brains are bathed in the same chemicals that create mood and motivation in us. We are all mammals, and under the skin we are kin. Scientists have watched rats’ brains as they dream, and dogs’ brains showing love. In fact, sperm whales’ family structure is nearly identical to that of elephants. Animals living in stable social groups – apes and monkeys, wolves and wild dogs, hyenas and cats, various birds, some dolphins and others, know who they are and whom they are with. © 2017 Guardian News and Media Limited

Keyword: Emotions; Evolution
Link ID: 24197 - Posted: 10.16.2017

Rae Ellen Bichell Abstinence may have found its most impressive poster child yet: Diploscapter pachys. The tiny worm is transparent, smaller than a poppy seed and hasn't had sex in 18 million years. It's basically just been cloning itself this whole time. Usually, that's a solid strategy for going extinct, fast. What's its secret? "Scientists have been trying to understand how some animals can survive for millions of years without sex, because such strict, long-term abstinence is very rare in the animal world," says David Fitch, a biologist at New York University. Most plants and animals use sex to reproduce. As he and his colleagues report in the recent issue of Current Biology, this seemingly unimpressive roundworm seems to have developed a different way of copying its genes — one that leads to just enough mutations to give the worms room to adapt, but not enough to cause crippling defects. Sex is pretty great for a lot of reasons (unless, perhaps, you're a duck), but one is that's it's a good way to dodge the effects of bad mutations. "All organisms accumulate mutations," says Kristin Gunsalus, a developmental geneticist at New York University and a co-author of the study. Usually, the machinery that copies DNA makes a few mistakes each time a cell divides. In humans, says Gunsalus, there are about six errors per cell division. © 2017 npr

Keyword: Evolution; Sexual Behavior
Link ID: 24179 - Posted: 10.12.2017

By Josh Gabbatiss Some female dolphins have evolved a secret weapon in their sexual arms race with males: vaginas that protect them from fertilisation by unwelcome partners. Penises come in a wide variety of shapes and sizes, especially in dolphins and other cetaceans. That seems to imply a similar diversity in vaginas, but Dara Orbach of Dalhousie University, Canada, says there is “a huge lag” in our understanding of female genitalia. That is partly because it is tricky to visualise vaginal structure. To overcome this problem, Orbach has created silicone moulds of cetaceans’ vaginas, revealing complex folds and spirals. “There’s this unparalleled level of vaginal diversity that we had no idea existed before,” Orbach says. Similarly complex vaginal structures are found in several species of duck. Orbach’s collaborator Patricia Brennan of Mount Holyoke College, Massachusetts, has previously found evidence that duck vaginas have evolved to make it harder for males to force copulation. So Orbach wondered if female cetaceans’ unusual vaginas had also evolved to keep out unwanted sperm. Orbach, Brennan and their colleagues obtained genitals from marine mammals that had died of natural causes: common and bottlenose dolphins, common porpoises and common seals. They inflated the males’ penises with saline to see how they looked when they were erect, and compared them with the vaginal moulds. They also took CT scans of penises inserted into the corresponding vaginas, to determine whether they fitted in easily and the best positions. © Copyright New Scientist Ltd.

Keyword: Sexual Behavior; Evolution
Link ID: 24170 - Posted: 10.11.2017

By Giorgia Guglielmi This mantis shrimp (Gonodactylus smithii) might have a much more elaborate brain than previously thought. That’s the conclusion of the first study to peer into the head of more than 200 crustaceans, including crabs, shrimp, and lobsters. Researchers discovered that the brain of mantis shrimp contains memory and learning centers, called mushroom bodies, which so far have been seen only in insects. The team also found similar structures in close relatives of these sea creatures: cleaner shrimp, pistol shrimp, and hermit crabs. This may not be a coincidence, the researchers say, because mantis shrimp and their brethren are the only crustaceans that hunt over long distances and might have to remember where to get food. But the finding, reported in eLife, is likely to stir debate: Scientists agree that mushroom bodies evolved after the insect lineage split off from the crustacean lineage about 480 million years ago; finding these learning centers in mantis shrimp means that either mushroom bodies are much more ancient than scientists realized and were lost in all crustaceans but mantis shrimp, or that these structures are similar to their counterparts in insects but have evolved independently. © 2017 American Association for the Advancement of Science.

Keyword: Learning & Memory; Evolution
Link ID: 24158 - Posted: 10.07.2017

By Ann Gibbons The insult "You're a Neandertal!" has taken on dramatic new meaning in the past few years, as researchers have begun to identify the genes many of us inherited from our long-extinct relatives. By sequencing a remarkably complete genome from a 50,000-year-old bone fragment of a female Neandertal found in Vindija Cave in Croatia, researchers report online today in Science a new trove of gene variants that living people outside of Africa obtained from Neandertals. Some of this DNA could influence cholesterol levels, the accumulation of belly fat, and the risk of schizophrenia and other diseases. The genome is only the second from a Neandertal sequenced to such high quality that it can reliably reveal when, where, and what DNA was passed from Neandertals to modern humans—and which diseases it may be causing or preventing today. "It's really exciting because it's more than two times better to have two Neandertal genomes," says evolutionary genomicist Tony Capra of Vanderbilt University in Nashville. The first Neandertal genome was a composite drawn from three individuals from Vindija Cave. Then, over the past few years, ancient DNA researchers sequenced two more Neandertal genomes, including another high-quality sequence from an individual that lived 122,000 years ago in the Altai Mountains of Siberia. Together, the genomes showed that living Europeans and Asians carry traces of DNA from Neandertals who mated with members of Homo sapiens soon after our species left Africa. (Most Africans lack Neandertal DNA as a result.) © 2017 American Association for the Advancement of Science.

Keyword: Obesity; Evolution
Link ID: 24156 - Posted: 10.06.2017

Christie Wilcox Many tadpoles ward off predators with potent poisons — but those toxins also seem to help win battles with their own kind, a new study finds. Tadpoles of common toads (Bufo bufo) are more poisonous when raised in crowded conditions, which may give them a competitive edge, according to the work published on 23 September in Functional Ecology1. Many noxious plant species are known to modulate their defences to fend off different threats2, but it is less clear whether animals possess similar toxin-tuning abilities. Although predation pressure is known to induce tadpole chemical defences3, the new findings are the first unequivocal evidence of toxin synthesis spurred by competition in vertebrate animals. Being poisonous can make a species essentially inedible to predators, but making potent toxins comes at a metabolic cost — so it’s best to make that investment count. “It would be very profitable for such animals to kill two birds with one stone by using their anti-predatory toxins as chemical weapons against their competitors, too,” says the study’s lead author, Veronika Bókony, an ecologist with the Hungarian Academy of Sciences in Budapest. Common toads are equipped with bufadienolides, potent toxins that cause harm by accelerating and disrupting the heart’s rhythms4. Field studies have found that common toad toxicity varies geographically, with the intensity of competition being the most reliable predictor5. But it has been unclear whether such patterns occur because populations are genetically isolated from one another in different ponds, or whether they reflect defences induced by environmental factors. © 2017 Macmillan Publishers Limited,

Keyword: Neurotoxins; Evolution
Link ID: 24124 - Posted: 09.30.2017

Barbara J. King In 1981, the evolutionary biologist Stephen Jay Gould's book The Mismeasure of Man hit the presses. A take-down of studies purporting to demonstrate that the intelligence of humans is genetically determined — and that some human groups (read "white Western Europeans") are innately superior — the book exposed interpretive bias and scientific racism in the measurement of human intelligence. Different environmental histories across human groups, in fact, affect testing outcomes in significant ways: There is no innate superiority due to genes. The Mismeasure of Man ignited ferocious discussion (and the occasional subsequent correction) that has continued even in recent years across biology, anthropology, psychology and philosophy: Its argument mattered not only for how we do science, but how science entangles with issues of social justice. Now, psychologists David A. Leavens of the University of Sussex, Kim A. Bard of the University of Portsmouth, and William D. Hopkins of Georgia State University have framed their new Animal Cognition article, "The mismeasure of ape social cognition," around Gould's book. Ape (especially chimpanzee) social intelligence, the authors say, has been routinely mismeasured because apes are tested in comprehensively different circumstances from the children with whom they are compared — and against whose performance theirs is found to be lacking. Leavens et al. write: "All direct ape-human comparisons that have reported human superiority in cognitive function have universally failed to match the groups on testing environment, test preparation, sampling protocols, and test procedures." © 2017 npr

Keyword: Evolution; Intelligence
Link ID: 24123 - Posted: 09.29.2017

By Mary Bates North American walnut sphinx moth caterpillars (Amorpha juglandis) look like easy meals for birds, but they have a trick up their sleeves—they produce whistles that sound like bird alarm calls, scaring potential predators away. At first, scientists suspected birds were simply startled by the loud noise. But a new study presented at the International Symposium on Acoustic Communication by Animals in Omaha in July suggests a more sophisticated mechanism: the caterpillar’s whistle appears to mimic a bird alarm call, sending avian predators scrambling for cover. “This is the first instance of deceptive alarm calling between an insect and a bird, and it’s a novel defense form for an insect,” says Jessica Lindsay, the study’s first author and a graduate student in the lab of Kristin Laidre at the University of Washington. “I think that’s pretty wild.” When pecked by a bird, the caterpillars whistle by compressing their bodies like an accordion and forcing air out through specialized holes in their sides. The whistles are impressively loud, considering they are made by a two-inch long insect. They have been measured at over 80 dB from 5 cm away from the caterpillar, similar to the loudness of a garbage disposal. In a laboratory experiment a few years ago, birds responded to caterpillar whistles by jumping away and abandoning their predation attempts. The authors of that study had attributed their behavior to a general startle response. © 1986-2017 The Scientist

Keyword: Evolution
Link ID: 24112 - Posted: 09.26.2017

Robin Dunbar, Angela Saini, Ben Garrod, Adam Rutherford We were all gearing up for the summer of love when, in 1967, Desmond Morris’s The Naked Ape took us by storm. Its pitch was that humans really were just apes, and much of our behaviour could be understood in terms of animal behaviour and its evolution. Yes, we were naked and bipedal, but beneath the veneer of culture lurked an ancestral avatar. With his zoologist’s training (he had had a distinguished career studying the behaviour of fishes and birds at Oxford University as part of the leading international group in this field), he gave us a picture of who we really are. In the laid-back, blue-smoke atmosphere of the hippy era, the book struck a chord with the wider public – if for no other reason than that, in the decade of free love, it asserted that humans had the largest penis for body size of all the primates. The early 1960s had seen the first field studies of monkeys and apes, and a corresponding interest in human evolution and the biology of contemporary hunter-gatherers. Morris latched on to the fact that the sexual division of labour (the men away hunting, the women at home gathering) necessitated some mechanism to ensure the sexual loyalty of one’s mate – this was the era of free love, after all. He suggested that becoming naked and developing new erogenous zones (notably, ear lobes and breasts), not to mention face-to-face copulation (all but unknown among animals), helped to maintain the couple’s loyalty to each other. Morris’s central claim, that much of our behaviour can be understood in the context of animal behaviour, has surely stood the test of time, even if some of the details haven’t. Our hairlessness (at around 2m years ago) long predates the rise of pair bonds (a mere 200,000 years ago). It owes its origins to the capacity to sweat copiously (another uniquely human trait) in order to allow us to travel longer distances across sunny savannahs. But he is probably still right that those bits of human behaviour that enhance sexual experience function to promote pair bonds – even if pair bonds are not lifelong in the way that many then assumed. © 2017 Guardian News and Media Limited

Keyword: Sexual Behavior; Evolution
Link ID: 24107 - Posted: 09.25.2017

By Ann Gibbons Neandertals have long been seen as the James Deans of human evolution—they grew up fast, died young, and became legends. But now, a rare skeleton of a Neandertal child suggests that our closest cousins didn’t all lead such fast lives—and that our own long childhoods aren’t unique. The find may reveal how Neandertals, like humans, had enough energy to grow bigger brains. “We like the paper because it puts the idea of ‘Neanderthal exceptionalism’ to rest,” wrote anthropologist Marcia Ponce de León and neurobiologist Christoph Zollikofer from the University of Zurich in Switzerland (who are not authors of the new study) in an email. “RIP.” Researchers have long known that modern humans take almost twice as long as chimpanzees to reach adulthood and have wondered when and why our ancestors evolved the ability to prolong childhood and delay reproduction. Our distant ancestors, such as the famous fossil Lucy and other australopithecines, matured quickly and died young like chimps. Even early members of our own genus Homo, such as the 1.6-million-year-old skeleton of an H. erectus boy, grew up faster than we do. By providing your email address, you agree to send your email address to the publication. Information provided here is subject to Science's Privacy Policy. But by the time the earliest known members of our species, H. sapiens, were alive 300,000 years ago at Jebel Irhoud in Morocco, they were taking longer to grow up. A leading theory is that big brains are so metabolically expensive that humans have to delay the age of reproduction—and, hence, have longer childhoods—so first-time mothers are older and, thus, bigger and strong enough to have the energy to feed babies with such big brains after birth when their brains are doubling in size. © 2017 American Association for the Advancement of Science

Keyword: Evolution; Development of the Brain
Link ID: 24098 - Posted: 09.22.2017

By STEPH YIN Worms and fish do it. Birds and bees do it. But do jellyfish fall asleep? It seems like a simple question, but answering it required a multistep investigation by a trio of Caltech graduate students. Their answer, published Thursday in Current Biology, is that at least one group of jellyfish called Cassiopea, or the upside-down jellyfish, does snooze. The finding is the first documented example of sleep in an animal with a diffuse nerve net, a system of neurons that are spread throughout an organism and not organized around a brain. It challenges the common notion that sleep requires a brain. It also suggests sleep could be an ancient behavior because the group that includes jellyfish branched off from the last common ancestor of most living animals early on in evolution. Working together was natural for Claire Bedbrook, Michael Abrams and Ravi Nath. The three leading co-authors of the paper are all Ph.D. candidates in biology at the California Institute of Technology and close friends. The project started with an observation by Mr. Abrams that some upside-down jellyfish in his lab would immediately slow their pulsing when the lights were turned off. Over coffee one evening, he discussed this phenomenon with Mr. Nath, who had been studying sleep in roundworms and pondering whether other “simple” animals slept. The two decided to visit Mr. Abrams’s lab in the middle of the night, to see how the jellyfish were behaving. The Cassiopea, or upside-down, jellyfish, demonstrated patterns of behavior consistent with sleep, according to an experiment conducted by Caltech graduate students. Credit Jan Easter Photography In the darkened lab, they observed a tankful of jellyfish pulsing infrequently and staying still for long periods of time — jellyfish that looked, in other words, like they were sleeping. Ms. Bedbrook started to believe they were onto something. © 2017 The New York Times Company

Keyword: Sleep; Evolution
Link ID: 24097 - Posted: 09.22.2017