Jeff Tollefson Early humans in eastern Africa crafted advanced tools and displayed other complex behaviours tens of thousands of years earlier than previously thought, according to a trio of papers published on 15 March in Science1,2,3. Those advances coincided with — and may have been driven by — major climate and landscape changes. The latest evidence comes from the Olorgesailie Basin in Southern Kenya, where researchers have previously found traces of ancient relatives of modern human as far back as 1.2 million years ago. Evidence collected at sites in the basin suggests that early humans underwent a series of profound changes at some point before roughly 320,000 years ago. They abandoned simple hand axes in favour of smaller and more advanced blades made from obsidian and other materials obtained from distant sources. That shift suggests the early people living there had developed a trade network — evidence of growing sophistication in behaviour. The researchers also found gouges on black and red rocks and minerals, which indicate that early Olorgesailie residents used those materials to create pigments and possibly communicate ideas. All of these changes in human behaviour occurred during an extended period of environmental upheaval, punctuated by strong earthquakes and a shift towards a more variable and arid climate. These changes occurred at the same time as larger animals disappeared from the site and were replaced by smaller creatures. “It’s a one-two punch combining tectonic shifts and climate shifts,” says Rick Potts, who led the work as director of the human origins programme at the Smithsonian Institution in Washington DC. “That’s the kind of stuff out of which evolution arises.” Researchers from the Smithsonian Institution digging in the Olorgesailie Basin in Kenya. © 2018 Macmillan Publishers Limited

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 24759 - Posted: 03.16.2018

By Elizabeth Pennisi Although it’s hard to believe that delicate nervous tissues could persist for hundreds of millions of years, that’s exactly what happened to the brains and eyes of some 15 ancestors of modern-day spiders and lobsters, called Kerygmachela kierkegaardi (after the famous philosopher Søren Kierkegaard). Found along the coast of north Greenland, the 518-million-year-old fossils contained enough preserved brains and eyes to help researchers write a brand-new history of the arthropod nervous system. Until now, many biologists had argued that ancient arthropods—which gave rise to today’s insects, spiders, and crustaceans—had a three-part brain and very simple eyes. Compound eyes, in which the “eye” is really a cluster of many smaller eyes, supposedly evolved later from a pair of legs that moved into the head and was modified to sense light. But these new fossils, which range from a few centimeters to 30 centimeters long, had a tiny, unsegmented brain, akin to what’s seen in modern velvet worms, researchers report today in Nature Communications. Despite the simple brain, Kerygmachela’s eyes were probably complex, perhaps enough to form rudimentary images. The eyes, indicated by shiny spots in the fossil’s small head, appear to be duplicated versions of the small, simple eyes seen today in soft, primitive arthropods called water bears and velvet worms. © 2018 American Association for the Advancement of Science.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 24734 - Posted: 03.10.2018

By Alexandra Rosati The shift to a cooked-food diet was a decisive point in human history. The main topic of debate is when, exactly, this change occurred. All known human societies eat cooked foods, and biologists generally agree cooking could have had major effects on how the human body evolved. For example, cooked foods tend to be softer than raw ones, so humans can eat them with smaller teeth and weaker jaws. Cooking also increases the energy they can get from the food they eat. Starchy potatoes and other tubers, eaten by people across the world, are barely digestible when raw. Moreover, when humans try to eat more like chimpanzees and other primates, we cannot extract enough calories to live healthily. Up to 50 percent of women who exclusively eat raw foods develop amenorrhea, or lack of menstruation, a sign the body does not have enough energy to support a pregnancy—a big problem from an evolutionary perspective. Such evidence suggests modern humans are biologically dependent on cooking. But at what point in our evolutionary history was this strange new practice adopted? Some researchers think cooking is a relatively recent innovation—at most 500,000 years old. Cooking requires control of fire, and there is not much archaeological evidence for hearths and purposefully built fires before this time. The archaeological record becomes increasingly fragile farther back in time, however, so others think fire may have been controlled much earlier. Anthropologist Richard Wrangham has proposed cooking arose before 1.8 million years ago, an invention of our evolutionary ancestors. If the custom emerged this early, it could explain a defining feature of our species: the increase in brain size that occurred around this time. © 2018 Scientific American,

Related chapters from BN: 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: 24698 - Posted: 02.26.2018

Emma Marris Neanderthals painted caves in what is now Spain before their cousins, Homo sapiens, even arrived in Europe, according to research published today in Science1. The finding suggests that the extinct hominids, once assumed to be intellectually inferior to humans, may have been artists with complex beliefs. Ladder-like shapes, dots and handprints were painted and stenciled deep in caves at three sites in Spain. Their precise meaning may forever be unknowable, says Alistair Pike, an archaeologist at the University of Southampton, UK, who co-authored the study, but they were almost certainly meaningful to our lost kin. “It wasn’t simply decorating your living space,” Pike says. “People were making journeys into the darkness.” Humans are thought to have arrived in Europe from Africa around 40,000–45,000 years ago. The three caves in different parts of Spain yielded artworks that are at least 65,000 years old, according to uranium-thorium dating of calcium carbonate that had formed on top of the art. These mineral deposits develop slowly, as water containing calcium comes into contact with cave surfaces. The water also contains trace levels of uranium from the rock. After the calcium carbonate has precipitated out of the water, a clock of sorts begins to tick, as uranium decays into thorium at a steady, known rate. Uranium-thorium dating has been used in geology for decades, but has seldom been employed to estimate the age of cave art. Some archaeologists are sceptical of the approach. They suggest that the calcium carbonate could have dissolved and re-crystallized after it was first formed — a process that could have also washed away some uranium, making a sample of the mineral appear older than it is. 2018 Macmillan Publishers Limited,

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 24693 - Posted: 02.23.2018

By C. CLAIBORNE RAY Q. Does an octopus have a brain? Where is it? And just how smart is an octopus? A. In a sense, an octopus has several brains, collections of neurons that control each arm. A famous 2001 study in the journal Science described how the commands that control one arm’s movement continue even when connections to the walnut-sized central processing system in the head are severed. Since then, more has been found about why the octopus is so much smarter than the average seafood. Even the relatively small central brain of an octopus is the largest among all invertebrates — proportionally, that is. A review article in 2015 in the journal Current Opinion in Neurobiology summarized the complexity of learning processes in the octopus and its remarkable adaptability. Some studies have examined the cephalopod’s ability to discern objects of different sizes, shapes, colors, brightnesses and textures; and its problem-solving, including the ability to navigate mazes and open jars. The creature also displays both short-term and long-term memory and recall over periods of weeks and even months. A possible explanation of the advanced abilities of the octopus lies in its very large genome, decoded in 2015 in a study in the journal Nature. The researchers surmised that the vast expansion of certain gene families in the octopus, and the network of linkages among the genes, could account for the development of its neurological complexity. © 2018 The New York Times Company

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 24602 - Posted: 02.02.2018

Ewen Callaway The oldest human fossils ever found outside Africa suggest that Homo sapiens might have spread to the Arabian Peninsula around 180,000 years ago — much earlier than previously thought. The upper jaw and teeth, found in an Israeli cave and reported in Science on 25 January1, pre-date other human fossils from the same region by at least 50,000 years. But scientists say that it is unclear whether the fossils represent a brief incursion or a more-lasting expansion of the species. Researchers originally thought that H. sapiens emerged in East Africa 200,000 years ago then moved out to populate the rest of the world. Until discoveries in the past decade countered that story, scientists thought that a small group left Africa some 60,000 years ago and that signs of earlier travels, including 80,000–120,000 year-old skulls and other remains from Israel discovered in the 1920s and 1930s, were from failed migrations. However, recent discoveries have muddied that simple narrative. Some H. sapiens-like fossils from Morocco that are older than 300,000 years, reported last year2, have raised the possibility that humans evolved earlier and perhaps elsewhere in Africa. Teeth from southern China, described in 20153, hint at long-distance migrations some 120,000 years ago. And genome studies have sown more confusion, with some comparisons of global populations pointing to just one human migration from Africa4,5, and others suggesting multiple waves6. © 2018 Macmillan Publishers Limited,

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 24570 - Posted: 01.26.2018

By Bret Stetka Fossil records can tell us a lot about our evolutionary past: what our ancestors looked like, how they walked, what they ate. But what bits of bone don’t typically reveal is why humans evolved the way we did—why, compared with all other known species, we wound up capable of such complex thought, emotion and behavior. A team of researchers has now used a novel technique to form a hypothesis on the origins of our rich cognitive abilities. They did so by profiling the chemicals buzzing around our brains. These compounds, known as neurotransmitters, are the signaling molecules responsible for key brain functions. Their research reveals that in comparison with other higher primates, our brains have unique neurotransmitter profiles that probably resulted in our enhanced cognition. The authors of the new study—a multicenter effort led by Kent State University anthropologists C. Owen Lovejoy and Mary Ann Raghanti and published January 22 in PNAS—began by measuring neurotransmitter levels in brain samples from humans, chimpanzees, gorillas, baboons and monkeys, all of whom had died of natural causes. Specifically, they tested levels in the striatum, a brain region involved in social behaviors and interactions. Compared with the other species tested, humans had markedly increased striatal dopamine activity. Among other functions, dopamine helps drive reward activity and social behaviors. In the striatum in particular it contributes to uniquely human abilities and behaviors like complicated social group formation and, in part, speech and language. © 2018 Scientific American,

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 24567 - Posted: 01.25.2018

Bruce Bower Big brains outpaced well-rounded brains in human evolution. Around the time of the origins of our species 300,000 years ago, the brains of Homo sapiens had about the same relatively large size as they do today, new research suggests. But rounder noggins rising well above the forehead — considered a hallmark of human anatomy — didn’t appear until between about 100,000 and 35,000 years ago, say physical anthropologist Simon Neubauer and his colleagues. Using CT scans of ancient and modern human skulls, the researchers created digital brain reconstructions, based on the shape of the inner surface of each skull’s braincase. Human brains gradually evolved from a relatively flatter and elongated shape — more like that of Neandertals’ — to a globe shape thanks to a series of genetic tweaks to brain development early in life, the researchers propose January 24 in Science Advances. A gradual transition to round brains may have stimulated considerable neural reorganization by around 50,000 years ago. That cognitive reworking could have enabled a blossoming of artwork and other forms of symbolic behavior among Stone Age humans, the team suspects. Other researchers have argued, however, that abstract and symbolic thinking flourished even before H. sapiens emerged (SN: 12/27/14, p. 6). Ancient DNA studies indicate that genes involved in brain development changed in H. sapiens following a split from Neandertals more than 600,000 years ago (SN Online: 3/14/16). “Those genetic changes might be responsible for differences in neural wiring and brain growth that led to brain [rounding] in modern humans, but not in Neandertals,” says Neubauer of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. |© Society for Science & the Public 2000 - 2017

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 24566 - Posted: 01.25.2018

Hanneke Meijer Even though I am better with dead birds than with living ones, I do enjoy watching them. Their behaviour is fascinating, and as Jennifer Ackerman points out in her book, birds are a lot more intelligent than we often give them credit for. But what do we know about the evolution of bird intelligence? How did the bird brain evolve, and when did it take on its “birdiness”? The fossil record isn’t particularly well-suited for the preservation of soft tissue such as brains – and behaviour doesn’t fossilise at all. However, some inferences regarding behaviour can be made based on anatomy, something the fossil record is rife with. When we look at the anatomical evidence of bird behaviour in the fossil record (Naish, 2014), it becomes clear that certain types of behaviour we see in modern birds – such as colonial nesting, parental care and plumage display – evolved a long time ago, and are likely dinosaurian in origin. The avian brain itself is a modified version of the basic archosaur brain (archosaurs are the group of reptiles that gave rise to crocodiles and dinosaurs). The archosaur brain, as seen in living crocodiles, is a relatively simple, tube-like structure consisting of the hindbrain, mid-brain and forebrain along a central axis. The bird brain has undergone significant enlargement of the forebrain and has folded along its main axis, resulting in a distinctive shape. Unfortunately, no fossilised bird brain has yet been found, but the shape and size of the inner brain cavity in fossilised skulls provides some information about brain shape and maximal brain dimensions. It should be noted here that the brain cavity is never an exact representation of the brain itself, as a significant portion of the endocranial space can be taken up by blood vessels, other soft tissues and fluid. © 2018 Guardian News and Media Limited

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 24539 - Posted: 01.19.2018

Laura Sanders If more nerve cells mean more smarts, then dogs beat cats, paws down, a new study on carnivores shows. That harsh reality may shock some friends of felines, but scientists say the real surprises are inside the brains of less popular carnivores. Raccoon brains are packed with nerve cells, for instance, while brown bear brains are sorely lacking. By comparing the numbers of nerve cells, or neurons, among eight species of carnivores (ferret, banded mongoose, raccoon, cat, dog, hyena, lion and brown bear), researchers now have a better understanding of how different-sized brains are built. This neural accounting, described in an upcoming Frontiers in Neuroanatomy paper, may ultimately help reveal how brain features relate to intelligence. For now, the multispecies tally raises more questions than it answers, says zoologist Sarah Benson-Amram of the University of Wyoming in Laramie. “It shows us that there’s a lot more out there that we need to study to really be able to understand the evolution of brain size and how it relates to cognition,” she says. Neuroscientist Suzana Herculano-Houzel of Vanderbilt University in Nashville and colleagues gathered brains from the different species of carnivores. For each animal, the researchers whipped up batches of “brain soup,” tissue dissolved in a detergent. Using a molecule that attaches selectively to neurons in this slurry, researchers could count the number of neurons in each bit of brain real estate. |© Society for Science & the Public 2000 - 2017.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System
Related chapters from MM:Chapter 1: Cells and Structures: The Anatomy of the Nervous System
Link ID: 24430 - Posted: 12.16.2017

Amy Maxmen A study of some of the world’s most obscure marine life suggests that the central nervous system evolved independently several times — not just once, as previously thought1. The invertebrates in question belong to families scattered throughout the animal evolutionary tree, and they display a diversity of central nerve cord architectures. The creatures also activate genes involved with nervous system development in other, well-studied animals — but they often do it in non-neural ways, report the authors of the paper, published on 13 December in Nature. “This puts a stake in the heart of the idea of an ancestor with a central nerve cord,” says Greg Wray, an evolutionary developmental biologist at Duke University in Durham, North Carolina. “That opens up a lot of questions we don’t have answers to — like, if central nerve cords evolved independently in different lineages, why do they have so many similarities?” In 1875, German zoologist Anton Dohrn noted anatomical similarities between the central nerve cord that runs length-wise through the bodies of annelids — a group of invertebrates that includes earthworms — and the nerve cord in the spine of vertebrates. He proposed that the groups’ ancient common ancestor had a nerve cord that ran along its belly-side, as seen in annelids. He also suggested that this cord flipped to the back of the body in a more recent animal that gave rise to all vertebrates. © 2017 Macmillan Publishers Limited,

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 4: Development of the Brain
Link ID: 24424 - Posted: 12.14.2017

By Diana Kwon, Amanda Montañez Killer whales have group-specific dialects, sperm whales babysit one another’s young and bottlenose dolphins cooperate with other species. These social skills are all closely linked with the aquatic mammals’ brain sizes, according to a recent study in Nature Ecology & Evolution. Scientists first proposed a relation between social living and brain expansion, or encephalization, nearly three decades ago, when they observed that primate species with larger brains typically lived in bigger groups. This theory was later broadened to associate brain size with other social characteristics, such as resolving conflicts and allocating food. Michael Muthukrishna, an economic psychologist at the London School of Economics, and his colleagues went searching for a similar link between big brains and sociality in cetaceans—the mammalian order that includes whales, dolphins and porpoises. They compiled a comprehensive data set of cetacean brain and body mass, group size and social characteristics. The team’s analyses, which covered 90 species, revealed that brain size was best predicted by a score based on various social behaviors such as cooperation with other species, group hunting and complex vocalizations. Bigger brains were also linked to other factors, including dietary richness and geographical range. The authors say these results are consistent with theories that cetaceans developed large brains to deal with the challenges of living in information-rich social environments. Yet Robert Barton, an evolutionary biologist at Durham University in England, who did not take part in the work, cautions against drawing conclusions about causation from correlation. He also asserts that it is important to ex­­amine specific regions of the brain because they might evolve differently. For example, his own research team has found that nocturnal primates’ brains develop larger olfactory structures—regions associated with smell—than those found in species active during the day. © 2017 Scientific American

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 15: Language and Lateralization
Link ID: 24358 - Posted: 11.25.2017

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

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 1: Introduction: Scope and Outlook
Related chapters from MM:Chapter 20:
Link ID: 24344 - Posted: 11.21.2017

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

Related chapters from BN: 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: 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.

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
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

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 24202 - Posted: 10.17.2017

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

Related chapters from BN: 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: 24179 - Posted: 10.12.2017

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

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior; Chapter 1: Introduction: Scope and Outlook
Related chapters from MM:Chapter 20:
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

Related chapters from BN: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 24112 - Posted: 09.26.2017

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

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 4: Development of the Brain
Link ID: 24098 - Posted: 09.22.2017