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By Emily Benson Baby birds are sometimes known to shove their siblings out of the nest to gain their parents’ undivided attention, but barn owl chicks appear to be more altruistic. Scientists recorded the hissing calls of hungry and full barn owl nestlings (Tyto alba, pictured), then played the sounds back to single chicks settled in nests stocked with mice. The young owls that heard the squawks of their hungry kin delayed eating each rodent by an average of half an hour; those that heard cries indicating their invisible nest-mate was full ate the mice more quickly. The findings suggest that barn owl chicks give hungrier siblings a chance to eat first even when the nest is full of food, the researchers will report in an upcoming issue of Behavioral Ecology and Sociobiology. So is it true altruism? Maybe not. Nestlings may share food in exchange for help with grooming or to get the first crack at a later meal, the team says, suggesting a possible ulterior motive. © 2016 American Association for the Advancement of Science

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 22174 - Posted: 05.04.2016

By Sarah Kaplan We know where the human story started: In Africa, millions of years ago, with diminutive people whose brains were just a third of the size of ours. And we know where it ended: with us. Yet a lot of what happened in between is still debated, including the question of how humans' bodies and noggins got so much bigger than our ancestors'. The traditional thinking is that the growth of both was spurred by the process of natural selection. The evolutionary advantages of a big body and a big brain are plentiful, so it seems reasonable to think that each developed independent of the other in response to the demands of survival in a hostile world. But a new study in the journal Current Anthropology suggests that, while our brains are certainly an advantageous adaptation, our imposing physiques (such as they are) are more of an evolutionary fluke. That's because the genes that determine brain and body size are the same, argues Mark Grabowski, a fellow at the American Museum of Natural History. So as humans evolved bigger and bigger brains, our bodies "just got pulled along." Grabowski acknowledges that it may seem like a counterintuitive conclusion — most of us learned in high school biology that evolution is about adapting to circumstances and that only the fittest survive. We're not used to thinking of traits as a product of happenstance. But evolutionary scientists know that lots of traits — even ultimately beneficial ones — are just the luck of the draw.

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 22119 - Posted: 04.20.2016

By Virginia Morell Moths have an almost fatal attraction to lights—so much so that we say people are drawn to bad ends “like moths to a flame.” But in this age of global light pollution, that saying has a new poignancy: Moths, which are typically nocturnal insects, are dying in droves at artificial lights. The high levels of mortality should have evolutionary consequences, leading to moths that avoid lights, biologists say. To find out, two scientists tested the flight-to-light behavior of 1048 adult ermine moths (Yponomeuta cagnagella, shown above) in Europe. The researchers collected the insects in 2007 as larvae that had just completed their first molt. Three hundred and twenty came from populations that lived where the skies were largely dark; 728 were gathered in light polluted areas. They were raised in a lab with 16 hours of daylight and 8 hours of darkness daily while they completed their life stages. Two to 3 days after emerging as moths, they were released in a flight cage with a fluorescent tube at one side. Moths from high light pollution areas were significantly less attracted to the light than those from the darker zones, the scientists report in today’s issue of Biology Letters. Overall, moths from the light-polluted populations had a 30% reduction in the flight-to-light behavior, indicating that this species is evolving, as predicted, to stay away from artificial lights. That change should increase these city moths’ reproductive success. But their success comes at a cost: To avoid the lights, the moths are likely flying less, say the scientists, so they aren’t pollinating as many flowers or feeding as many spiders and bats. © 2016 American Association for the Advancement of Science.

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 22100 - Posted: 04.13.2016

By FRANS de WAAL TICKLING a juvenile chimpanzee is a lot like tickling a child. The ape has the same sensitive spots: under the armpits, on the side, in the belly. He opens his mouth wide, lips relaxed, panting audibly in the same “huh-huh-huh” rhythm of inhalation and exhalation as human laughter. The similarity makes it hard not to giggle yourself. The ape also shows the same ambivalence as a child. He pushes your tickling fingers away and tries to escape, but as soon as you stop he comes back for more, putting his belly right in front of you. At this point, you need only to point to a tickling spot, not even touching it, and he will throw another fit of laughter. Laughter? Now wait a minute! A real scientist should avoid any and all anthropomorphism, which is why hard-nosed colleagues often ask us to change our terminology. Why not call the ape’s reaction something neutral, like, say, vocalized panting? That way we avoid confusion between the human and the animal. The term anthropomorphism, which means “human form,” comes from the Greek philosopher Xenophanes, who protested in the fifth century B.C. against Homer’s poetry because it described the gods as though they looked human. Xenophanes mocked this assumption, reportedly saying that if horses had hands they would “draw their gods like horses.” Nowadays the term has a broader meaning. It is typically used to censure the attribution of humanlike traits and experiences to other species. Animals don’t have “sex,” but engage in breeding behavior. They don’t have “friends,” but favorite affiliation partners. Given how partial our species is to intellectual distinctions, we apply such linguistic castrations even more vigorously in the cognitive domain. By explaining the smartness of animals either as a product of instinct or simple learning, we have kept human cognition on its pedestal under the guise of being scientific. Everything boiled down to genes and reinforcement. To think otherwise opened you up to ridicule, which is what happened to Wolfgang Köhler, the German psychologist who, a century ago, was the first to demonstrate flashes of insight in chimpanzees. © 2016 The New York Times Company

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: 22091 - Posted: 04.11.2016

Modern humans diverged from Neanderthals some 600,000 years ago – and a new study shows the Y chromosome might be what kept the two species separate. It seems we were genetically incompatible with our ancient relatives – and male fetuses conceived through sex with Neanderthal males would have miscarried. We knew that some cross-breeding between us and Neanderthals happened more recently – around 100,000 to 60,000 years ago. Neanderthal genes have been found in our genomes, on X chromosomes, and have been linked to traits such as skin colour, fertility and even depression and addiction. Now, an analysis of a Y chromosome from a 49,000-year-old male Neanderthal found in El Sidrón, Spain, suggests the chromosome has gone extinct seemingly without leaving any trace in modern humans. This could simply be because it drifted out of the human gene pool or, as the new study suggests, it could be because genetic differences meant that hybrid offspring who had this chromosome were infertile – a genetic dead end. Fernando Mendez of Stanford University, and his colleagues compared the Neanderthal Y chromosome with that of chimps, and ancient and modern humans. They found mutations in four genes that could have prevented the passage of Y chromosome down the paternal line to the hybrid children. “Some of these mutations could have played a role in the loss of Neanderthal Y chromosomes in human populations,” says Mendez. © Copyright Reed Business Information Ltd.

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: 22088 - Posted: 04.09.2016

by Daniel Galef Footage from a revolutionary behavioural experiment showed non-primates making and using tools just like humans. In the video, a crow is trying to get food out of a narrow vessel, but its beak is too short for it to reach through the container. Nearby, the researchers placed a straight wire, which the crow bent against a nearby surface into a hook. Then, holding the hook in its beak, it fished the food from the bottle. Corvids—the family of birds that includes crows, ravens, rooks, jackdaws, and jays—are pretty smart overall. Although not to the level of parrots and cockatoos, ravens can also mimic human speech. They also have a highly developed system of communication and are believed to be among the most intelligent non-primate animals in existence. McGill Professor Andrew Reisner recalls meeting a graduate student studying corvid intelligence at Oxford University when these results were first published in 2015. “I had read early in the year that some crows had been observed making tools, and I mentioned this to him,” Reisner explained. “He said that he knew about that, as it had been he who had first observed it happening. Evidently the graduate students took turns watching the ‘bird box,’ […] and the tool making first occurred there on his shift.”

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 13: Memory, Learning, and Development
Link ID: 22072 - Posted: 04.06.2016

Ewen Callaway Homo floresiensis, the mysterious and diminutive species found in Indonesia in 2003, is tens of thousands of years older than originally thought — and may have been driven to extinction by modern humans. After researchers discovered H. floresiensis, which they nicknamed the hobbit, in Liang Bua cave on the island of Flores, they concluded that its skeletal remains were as young as 11,000 years old. But later excavations that have dated more rock and sediment around the remains now suggest that hobbits were gone from the cave by 50,000 years ago, according to a study published in Nature on 30 March1. That is around the time that modern humans moved through southeast Asia and Australia. “I can’t believe that it is purely coincidence, based on what else we know happens when modern humans enter a new area,” says Richard Roberts, a geochronologist at the University of Wollongong, Australia. He notes that Neanderthals vanished soon after early modern humans arrived in Europe from Africa. Roberts co-led the study with archaeologist colleague Thomas Sutikna (who also helped coordinate the 2003 dig), and Matthew Tocheri, a paleoanthropologist at Lakehead University in Thunder Bay, Canada. The first hobbit fossil, known as LB1, was found in 20032 beneath about 6 metres of dirt and rock. Its fragile bones were too precious for radiocarbon dating, so the team collected nearby charcoal, on the assumption that it had accrued at the same time as the bones. That charcoal was as young as 11,000 years old, researchers reported at the time3, 4. “Somehow these tiny people had survived on this island 30,000 years after modern humans arrived,” says Roberts. “We were scratching our heads. It couldn’t add up.” © 2016 Nature Publishing Group,

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 22055 - Posted: 03.31.2016

By NATALIE ANGIER Juan F. Masello never intended to study wild parrots. Twenty years ago, as a graduate student visiting the northernmost province of Patagonia in Argentina, he planned to write his dissertation on colony formation among seabirds. But when he asked around for flocks of, say, cormorants or storm petrels, a park warden told him he was out of luck. “He said, ‘This is the only part of Patagonia with no seabird colonies,’” recalled Dr. Masello, a principal investigator in animal ecology and systematics at Justus Liebig University in Germany. Might the young scientist be interested in seeing a large colony of parrots instead? The sight that greeted Dr. Masello was “amazing” and “incredible,” he said. “It was almost beyond words.” On a 160-foot-high sandstone cliff that stretched some seven miles along the Atlantic coast, tens of thousands of pairs of burrowing parrots had used their powerful bills to dig holes — their nests — deep into the rock face. And when breeding season began not long afterward, the sky around the cliffs erupted into a raucous carnival of parrot: 150,000 crow-size, polychromed aeronauts with olive backsides, turquoise wings, white epaulets and bright red belly patches ringed in gold. Dr. Masello was hooked. Today, Dr. Masello’s hands are covered with bite scars. He has had four operations to repair a broken knee, a broken nose — “the little accidents you get from working with parrots,” he said. Still, he has no regrets. “Their astonishing beauty and intelligence,” Dr. Masello said, “are inspirational.” © 2016 The New York Times Company

Related chapters from BP7e: Chapter 17: Learning and Memory; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory, Learning, and Development
Link ID: 22016 - Posted: 03.22.2016

How did evolution produce a monstrous killer like T. rex? A fossil find in Central Asia is giving scientists a glimpse of the process. T. rex and other tyrannosaurs were huge, dominant predators, but they evolved from much smaller ancestors. The new discovery from Uzbekistan indicates that this supersizing happened quickly, and only after the appearance of some anatomical features that may have helped the monster tyrannosaurs hunt so effectively. The finding was reported Monday by Hans-Dieter Sues of the Smithsonian's National Museum of Natural History in Washington, Stephen Brusatte of the University of Edinburgh in Scotland, and others in a paper released by the Proceedings of the National Academy of Sciences. The discovery They report finding bones of a previously unknown member of the evolutionary branch that led to the huge tyrannosaurs. This earlier dinosaur lived about 90 million years ago, south of what is now the Aral Sea. It looked roughly like a T. rex, but was only about 10 to 12 feet long and weighed only about 600 pounds at most, Sues said. T. rex grew about four times as long and weighed more than 20 times as much. The discovery helps fill in a frustrating gap in the tyrannosaur fossil record. Before that gap, which began some 100 million years ago, the ancestral creatures were only about as big as a horse. Right after the gap, at about 80 million years ago, tyrannosaurs were multi-ton behemoths like T. rex. The new finding shows the forerunners were still relatively small even just 90 million years ago. So the size boom happened pretty quickly. Standard equipment ©2016 CBC/Radio-Canada.

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 21989 - Posted: 03.15.2016

Carl Zimmer Scientists recently turned Harvard’s Skeletal Biology Laboratory into a pop-up restaurant. It would have fared very badly on Yelp. Katherine D. Zink, then a graduate student, acted as chef and waitress. First, she attached electrodes to the jaws of diners to record the activity in the muscles they use to chew food. Then she brought out the victuals. Some volunteers received a three-course vegetarian meal of carrots, yams or beets. In one course, the vegetables were cooked; in the second, they were raw and sliced; in the last course, Dr. Zink simply served raw chunks of plant matter. Other patrons got three courses of meat (goat, in this case). Dr. Zink grilled the meat in the first course, but offered it raw and sliced in the second. In the third course, her volunteers received an uncooked lump of goat flesh. In some of the trials, the volunteers chewed the food until it was ready to swallow and then spat it out. Dr. Zink painstakingly picked apart those food bits and measured their size. Every week, we'll bring you stories that capture the wonders of the human body, nature and the cosmos. “If that was all my dissertation was, I would have quit graduate school,” Dr. Zink said. “It was as lovely as it sounds.” Dr. Zink persevered, however, because she was exploring a profound question about our origins: How did our ancestors evolve from small-brained, big-jawed apes into large-brained, small-jawed humans? Scientists studying the fossil record have long puzzled over this transition, which happened around two million years ago. Before then, early human relatives — known as hominins — were typically about the size of chimpanzees, with massive teeth and a brain only a third the size of humans’ current brains. © 2016 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: 21975 - Posted: 03.10.2016

It’s the most ancient nervous system we’ve ever seen, preserved inside 520 million-year-old fossils. What’s more, the nervous systems of these creatures’ modern-day descendants are less intricate, proving that evolution isn’t a one-way street to complexity. Found in South China, the five Cambrian fossils belonged to a group of organisms that gave rise to the arthropods, including insects, spiders and crustaceans. The fossils are of Chengjiangocaris kunmingensis, a creature around 10 centimetres long, with a segmented body, multiple pairs of legs and a heart-shaped head. But most interesting of all is its nerve cord and associated neurons. Together, the fossils show the entire nervous system of the organism, apart from its brain – making this the oldest preserved nervous system that has ever been found. “The detail of this fossil is exquisite,” says Rob DeSalle of the American Museum of Natural History in New York, who was not involved in the work. “The information from this specimen unravels transitions in how the nervous systems of arthropods evolved.” The animal had a nerve cord that ran the length of its body, with bulbous nodes of neurons called ganglia located between each pair of legs. “It’s almost like a mini-brain for each pair of legs,” says Javier Ortega-Hernández of the University of Cambridge, whose team analysed and described the fossil. Surprisingly, the team found dozens of fine, subsidiary nerves fanning out across the entire length of the nerve cord, making this nervous system more complex than those seen in today’s descendants. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 21941 - Posted: 03.01.2016

By Elahe Izadi Tiny cameras attached to wild New Caledonian crows capture, for the first time, video footage of these elusive birds fashioning hooked stick tools, according to researchers. These South Pacific birds build tools out of twigs and leaves that they use to root out food, and they're the only non-humans that make hooked tools in the wild, write the authors of a study published Wednesday in the journal Biology Letters. Humans have previously seen the crows making the tools in artificial situations, in which scientists baited feeding sites and provided the raw tools; but researchers say the New Caledonian crows have never been filmed doing this in a completely natural setting. "New Caledonian crows are renowned for their unusually sophisticated tool behavior," the study authors write. "Despite decades of fieldwork, however, very little is known about how they make and use their foraging tools in the wild, which is largely owing to the difficulties in observing these shy forest birds." Study author Jolyon Troscianko of the University of Exeter in England described the tropical birds as "notoriously difficult to observe" because of the terrain of their habitat and their sensitivity to disturbance, he said in a press release. "By documenting their fascinating behavior with this new camera technology, we obtained valuable insights into the importance of tools in their daily search for food," he added.

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: 21719 - Posted: 12.24.2015

By Diana Kwon The human brain is unique: Our remarkable cognitive capacity has allowed us to invent the wheel, build the pyramids and land on the moon. In fact, scientists sometimes refer to the human brain as the “crowning achievement of evolution.” But what, exactly, makes our brains so special? Some leading arguments have been that our brains have more neurons and expend more energy than would be expected for our size, and that our cerebral cortex, which is responsible for higher cognition, is disproportionately large—accounting for over 80 percent of our total brain mass. Suzana Herculano-Houzel, a neuroscientist at the Institute of Biomedical Science in Rio de Janeiro, debunked these well-established beliefs in recent years when she discovered a novel way of counting neurons—dissolving brains into a homogenous mixture, or “brain soup.” Using this technique she found the number of neurons relative to brain size to be consistent with other primates, and that the cerebral cortex, the region responsible for higher cognition, only holds around 20 percent of all our brain’s neurons, a similar proportion found in other mammals. In light of these findings, she argues that the human brain is actually just a linearly scaled-up primate brain that grew in size as we started to consume more calories, thanks to the advent of cooked food. Other researchers have found that traits once believed to belong solely to humans also exist in other members of the animal kingdom. Monkeys have a sense of fairness. Chimps engage in war. Rats show altruism and exhibit empathy. In a study published last week in Nature Communications, neuroscientist Christopher Petkov and his group at Newcastle University found that macaques and humans share brain areas responsible for processing the basic structures of language. © 2015 Scientific American

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior; Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 21668 - Posted: 12.01.2015

Human DNA is 1 to 2% Neandertal, or more, depending on where your ancestors lived. Svante Pääbo, founder of the field of paleogenetics and winner of a 2016 Breakthrough Prize, explains why that matters © 2015 Scientific American

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: 21650 - Posted: 11.21.2015

Now hear this. Anthropologists have estimated the hearing abilities of early hominins – reconstructing a human ancestor’s sensory perception. Rolf Quam from Binghamton University in New York and his colleagues studied skulls and ear bones from Australopithecus africanus and Paranthropus robustus, two species that lived between 1 million and 3 million years ago, as well as modern humans and chimpanzees. Using CT scans of the bones, they built 3D reconstructions of the ear of each species. Then they fed a series of anatomical measurements into a computer model to predict their hearing abilities. The results for humans and chimpanzees fitted well with laboratory data, suggesting the model aligned well with real performance. For each species, they then estimated the frequency range they can hear best. Modern humans and chimpanzees perform similarly below 3 kilohertz, but humans have better hearing than chimps in the 3-5 kHz range. The early hominins had a similar sensitive range to chimpanzees, but shifted slightly towards that of modern humans, so they have better hearing than chimps do for 3-4 kHz sounds. Australopithecus and Paranthropus are not believed to have been capable of language, but they almost certainly communicated vocally as other primates do, says Quam. Quam thinks this shift in hearing sensitivity would have helped them communicate in open environments, such as African savannahs, where human ancestors are thought to have evolved bipedalism. © Copyright Reed Business Information Ltd.

Related chapters from BP7e: Chapter 9: Hearing, Vestibular Perception, Taste, and Smell; Chapter 19: Language and Hemispheric Asymmetry
Related chapters from MM:Chapter 6: Hearing, Balance, Taste, and Smell; Chapter 15: Brain Asymmetry, Spatial Cognition, and Language
Link ID: 21446 - Posted: 09.26.2015

Mo Costandi At some point back in deep time, a group of fish were washed into a limestone cave somewhere in northeastern Mexico. With no way out and little more than bat droppings to eat, the fish began to adapt to their new troglodytic lifestyle. Unable to see other members of their group in the dark, they lost their colourful pigmentation. Then they lost their eyesight, their eyes gradually got smaller, and then disappeared altogether. This was accompanied by a dramatic reduction in the size of the brain’s visual system. Yet, the question of why the blind cave fish lost its eyes and a large part of its brain remains unresolved. Now, biologists in Sweden believe they have found the answer. In new research published today, they report that loss of the visual system saves the fish a substantial amount of energy, and was probably key to their stranded ancestors’ survival. The blind cave fish Astyanax mexicanus is adapted to its subterranean environment in other ways. As its vision regressed, it became more reliant on smell and taste, and its taste buds grew larger and more numerous. They also developed an enhanced ability to detect changes in mechanical pressure, which made them more sensitive to water movements. Last year, Damian Moran of Lund University and his colleagues reported that blind cave fish eliminated the circadian rhythm in their metabolism during their course of evolution, and that this leads to a massive 27% reduction in their energy expenditure. This new study was designed test whether or not they lost their visual system for the same reason. © 2015 Guardian News and Media Limited

Related chapters from BP7e: Chapter 10: Vision: From Eye to Brain; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 7: Vision: From Eye to Brain
Link ID: 21401 - Posted: 09.12.2015

By JOHN NOBLE WILFORD Acting on a tip from spelunkers two years ago, scientists in South Africa discovered what the cavers had only dimly glimpsed through a crack in a limestone wall deep in the Rising Star Cave: lots and lots of old bones. The remains covered the earthen floor beyond the narrow opening. This was, the scientists concluded, a large, dark chamber for the dead of a previously unidentified species of the early human lineage — Homo naledi. The new hominin species was announced on Thursday by an international team of more than 60 scientists led by Lee R. Berger, an American paleoanthropologist who is a professor of human evolution studies at the University of the Witwatersrand in Johannesburg. The species name, H. naledi, refers to the cave where the bones lay undisturbed for so long; “naledi” means “star” in the local Sesotho language. In two papers published this week in the open-access journal eLife, the researchers said that the more than 1,550 fossil elements documenting the discovery constituted the largest sample for any hominin species in a single African site, and one of the largest anywhere in the world. Further, the scientists said, that sample is probably a small fraction of the fossils yet to be recovered from the chamber. So far the team has recovered parts of at least 15 individuals. “With almost every bone in the body represented multiple times, Homo naledi is already practically the best-known fossil member of our lineage,” Dr. Berger said. The finding, like so many others in science, was the result of pure luck followed by considerable effort. Two local cavers, Rick Hunter and Steven Tucker, found the narrow entrance to the chamber, measuring no more than seven and a half inches wide. They were skinny enough to squeeze through, and in the light of their headlamps they saw the bones all around them. When they showed the fossil pictures to Pedro Boshoff, a caver who is also a geologist, he alerted Dr. Berger, who organized an investigation. © 2015 The New York Times Company

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 21396 - Posted: 09.11.2015

By Ann Gibbons From the moment in 2013 when paleoanthropologist Lee Berger posted a plea on Facebook, Twitter, and LinkedIn for “tiny and small, specialised cavers and spelunkers with excellent archaeological, palaeontological and excavation skills,” some experts began grumbling that the excavation of a mysterious hominin in the Rising Star Cave in South Africa was more of a media circus than a serious scientific expedition. Daily blogs recorded the dangerous maneuvers of “underground astronauts” who squeezed through a long, narrow chute to drop 30 meters into a fossil-filled cavern, while Berger, who is based at the University of the Witwatersrand in Johannesburg, South Africa, became the “voice from the cave” in radio interviews. When it came time to analyze the fossils, Berger put out a call for applications from “early career scientists” to study them at a workshop in Johannesburg in March 2014. Handing over much of the analysis of such potentially important specimens to inexperienced researchers didn’t inspire confidence among Berger’s colleagues either, though it did win him the nickname Mr. Paleodemocracy. Many thought the expedition “had more hype than substance,” paleoanthropologist Chris Stringer of the Natural History Museum in London writes in a commentary accompanying the fossils’ official presentation this week in the journal eLIFE. But the substance has now been unveiled, and few dispute that the findings are impressive. In their report, Berger and his team describe 1550 fossils representing more than 15 ancient members of a strange new kind of hominin, which they named Homo naledi. (Naledi means “star” in the Sotho language spoken in the region of the cave.) © 2015 American Association for the Advancement of Science.

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 21392 - Posted: 09.10.2015

Erin Wayman Nose picking isn’t a mark of distinction among people — but it is among monkeys. For the first time, researchers have reported a wild capuchin monkey using a tool to pick its nose and teeth. The monkey was caught in the act last year by Michael Haslam of the University of Oxford. For about five minutes, an adult female bearded capuchin (Sapajus libidinosus) in northeastern Brazil repeatedly inserted a twig or stem into its nostril, usually inducing a sneeze. The monkey also rubbed sticks back and forth against the base of its teeth, probably to dislodge debris, Haslam and Oxford colleague Tiago Falótico report in the July Primates. After picking its nose or teeth, the monkey often licked the tool tip, perhaps to wipe the stick clean. Bearded capuchins are quite handy, brandishing rocks to crack open nuts (SN Online: 4/30/15) and sticks to retrieve insects from crevices or to collect honey. But until now, no one had seen a wild capuchin use a tool as a nasal probe or toothpick. M. Haslam and T. Falótico. Nasal probe and toothpick tool use by a wild female bearded capuchin (Sapajus libidinosus). Primates. Vol. 56, July 2015, p. 211. doi: 10.1007/s10329-015-0470-6. © Society for Science & the Public 2000 - 2015

Related chapters from BP7e: Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:None
Link ID: 21382 - Posted: 09.08.2015

Carl Zimmer You are what you eat, and so were your ancient ancestors. But figuring out what they actually dined on has been no easy task. There are no Pleistocene cookbooks to consult. Instead, scientists must sift through an assortment of clues, from the chemical traces in fossilized bones to the scratch marks on prehistoric digging sticks. Scientists have long recognized that the diets of our ancestors went through a profound shift with the addition of meat. But in the September issue of The Quarterly Review of Biology, researchers argue that another item added to the menu was just as important: carbohydrates, bane of today’s paleo diet enthusiasts. In fact, the scientists propose, by incorporating cooked starches into their diet, our ancestors were able to fuel the evolution of our oversize brains. Roughly seven million years ago, our ancestors split off from the apes. As far as scientists can tell, those so-called hominins ate a diet that included a lot of raw, fiber-rich plants. After several million years, hominins started eating meat. The oldest clues to this shift are 3.3-million-year-old stone tools and 3.4-million-year-old mammal bones scarred with cut marks. The evidence suggests that hominins began by scavenging meat and marrow from dead animals. At some point hominins began to cook meat, but exactly when they invented fire is a question that inspires a lot of debate. Humans were definitely making fires by 300,000 years ago, but some researchers claim to have found campfires dating back as far as 1.8 million years. Cooked meat provided increased protein, fat and energy, helping hominins grow and thrive. But Mark G. Thomas, an evolutionary geneticist at University College London, and his colleagues argue that there was another important food sizzling on the ancient hearth: tubers and other starchy plants. © 2015 The New York Times Company

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: 21299 - Posted: 08.15.2015