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28 Evolution News Articles
for April 2021
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4-10-21 Basic income trial is testing how money affects child development
Growing up in poverty can have long-term negative consequences for children. Now, a study offering unconditional cash to a group of mothers on low-incomes in the US is beginning to discover the precise role of parental income in child development. It is the first randomised trial to look at whether a basic income might affect the way a child’s brain develops in this critical period. Studies of children born into families with low income have found they tend to have more behavioural problems and are behind their peers when they start school. We know that the first few years of a child’s life are the most influential for their development, and brain development is particularly rapid in early childhood and therefore more likely to be influenced by the environment. However, it isn’t clear whether income directly causes these outcomes, or whether they are a result of other factors associated with growing up in poverty. To find out, Kimberly Noble at Columbia University and her colleagues approached women on low incomes who had just given birth at four sites in the US, and asked them if they would take part in a study following their child’s development. Around 1000 women accepted and were randomly assigned to one of two groups. The first group, consisting of 40 per cent of the women, received an unconditional monthly cash gift which added up to $333 per month, and the other group received $20 per month. Both groups will receive the money for the first 40 months of their child’s life. The first babies in the study were born in May 2018, and the team have been following up every year. Preliminary findings from the first year were presented this week at the virtual Society for Research in Child Development Conference. “To date, the dots are not connected in a careful scientific way,” one of the study authors Katherine Magnuson at the University of Wisconsin-Madison told the conference. “We still don’t know whether the types of early experiences that poverty creates for children will directly impact their early development and specifically their brain development in any meaningful way.”

4-10-21 Animals with weird neurons may rewrite the story of brain evolution
Marine animals called comb jellies have nervous systems unlike those of any other known animal. Their neurons are oddly shaped and use chemicals not found in those of other animals. “These neurons are quite unique,” says Pawel Burkhardt at the University of Bergen in Norway. The comb jellies’ peculiar neurons may be an adaptation for their lifestyle and the way their bodies work. They also add to the ongoing debate among evolutionary biologists about how the first animal brains evolved. In particular, there is controversy over whether brains evolved once in very early animals, or several times in different groups. Comb jellies, or ctenophores, are one of the oldest animal groups – and the oldest group to have a nervous system. Though they look a bit like jellyfish, they have a distinct evolutionary history. Their name comes from the “combs” that run along the outsides of their bodies. Each comb is a row of tiny tentacles, which propel the comb jelly through the water. Comb jellies don’t have a large central brain. Instead they have a thin net of neurons. “What was elusive so far was what is going on with the nervous system,” says Burkhardt. Neurons in other animals produce characteristic chemicals, in particular, small proteins called neuropeptides. But nobody had identified neuropeptides in comb jelly neurons. Burkhardt’s team studied a comb jelly called Mnemiopsis leidyi, whose genome had already been sequenced. The researchers used a machine-learning tool to predict 129 possible neuropeptides from the genome. They then grew M. leidyi in the lab, and identified 16 of these neuropeptides in their neurons. They were unlike those seen in any other animal. “They took a big risk in taking this approach and I think it paid off,” says Leslie Babonis of Cornell University in New York.

4-9-21 'Lost golden city' found in Egypt reveals lives of ancient pharaohs
The discovery of a 3,000-year-old city that was lost to the sands of Egypt has been hailed as one of the most important archaeological finds since Tutankhamun's tomb. Famed Egyptologist Zahi Hawass announced the discovery of the "lost golden city" near Luxor on Thursday. He said the find was the largest ancient city, known as Aten, ever uncovered in Egypt. It was unearthed within weeks of the excavation starting in September 2020. The city dates to the reign of Amenhotep III, one of Egypt's most powerful pharaohs, who ruled from 1391 to 1353 BC. The city continued to be used by pharaohs Ay and Tutankhamun, whose nearly intact tomb was discovered in the Valley of the Kings by British archaeologist Howard Carter in 1922. "The discovery of this lost city is the second most important archaeological discovery since the tomb of Tutankhamun," Betsy Brian, professor of Egyptology at Johns Hopkins University in Baltimore, US, said. She said the city would "give us a rare glimpse into the life of the ancient Egyptians" at the time when the empire was at its wealthiest. The dig revealed a large number of valuable archaeological finds, such as jewellery, coloured pottery, scarab beetle amulets and mud bricks bearing seals of Amenhotep III. The team began excavations on the west bank of Luxor near the Valley of the Kings, some 500 km (300 miles) south of the capital Cairo. "Within weeks, to the team's great surprise, formations of mud bricks began to appear in all directions," Dr Hawass said in his statement. "What they unearthed was the site of a large city in a good condition of preservation, with almost complete walls, and with rooms filled with tools of daily life." Now, seven months after the dig started, several areas or neighbourhoods have been uncovered, including a bakery, an administrative district and a residential area. "Many foreign missions searched for this city and never found it," said Dr Hawass, a former antiquities minister. He said further archaeological work was under way at the site and his team "expects to uncover untouched tombs filled with treasures".

4-9-21 Ancient humans may have had apelike brains even after leaving Africa
Modern humanlike brains may have emerged in an evolutionary sprint about 1.7 million years ago. Even after ancient humans took their first steps out of Africa, they still unexpectedly may have possessed brains more like those of great apes than modern humans, a new study suggests. For decades, scientists had thought modern humanlike organization of brain structures evolved soon after the human lineage Homo arose roughly 2.8 million years ago (SN: 3/4/15). But an analysis of fossilized human skulls that retain imprints of the brains they once held now suggests such brain development occurred much later. Modernlike brains may have emerged in an evolutionary sprint starting about 1.7 million years ago, researchers report in the April 9 Science. What sets modern humans apart most from our closest living relatives, the great apes, is most likely our brain. To learn more about how the modern human brain evolved, the researchers analyzed replicas of the brain’s convoluted outer surface, re-created from the oldest known fossils to preserve the inner surfaces of early human skulls. The 1.77-million to 1.85-million-year-old fossils are from the Dmanisi archaeological site in the modern-day nation of Georgia and were compared with bones from Africa and Southeast Asia ranging from roughly 2 million to 70,000 years old. The scientists focused on the brain’s frontal lobes, which are linked with complex mental tasks such as toolmaking and language. Early Homo from Dmanisi and Africa still apparently retained a great ape–like organization of the frontal lobe 1.8 million years ago, “a million or so years later than previously thought,” says paleoanthropologist Philipp Gunz at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who did not take part in this study.

4-8-21 People expect chocolate to taste bitter if it is in black packaging
People expect chocolate to be more bitter-tasting if it is in black packaging, while yellow and pink packaging is associated with sweeter-tasting chocolate. Iuri Baptista at the University of Campinas in Brazil and his colleagues wanted to investigate how people respond to the colour of chocolate packaging. The researchers sent a survey to 420 people between the ages of 18-60. Half of the participants were in Brazil and the other half were in France. The survey contained two photographs of milk chocolate bars and two of dark chocolate bars. Each chocolate bar came in packaging of a specific colour – either black, blue, brown, green, red, pink or yellow. The participants were asked to rank each chocolate bar on a scale of 1-9 for different attributes, including how sweet or bitter they expected the chocolate to taste. To avoid any bias, they were not told the purpose of the study. People expected both milk and dark chocolates to be the least sweet and most bitter if its packaging was black. Conversely, the participants expected the chocolates in yellow or pink packaging to be the sweetest and least bitter. “The colour of packaging changes how the consumer expects the chocolate to taste,” says Baptista. The participants were also asked how much they expected to like each chocolate bar. Milk chocolate was rated as most likely to be enjoyed if it came in black packaging – but dark chocolate was least likely to be enjoyed when it was placed in exactly the same black packaging. There was no appreciable difference between the responses of the participants in Brazil and those in France. This surprised the team considering both countries have very different chocolate-eating habits, says Baptista. On average, a person in France will eat 7.3 kilograms of chocolate per year versus just 2.8 kilograms in Brazil. French people also eat chocolate with a higher cocoa content than Brazilian people.

4-8-21 People add by default even when subtraction makes more sense
This tendency to think more is better could underlie modern-day excesses, experts say. Picture a bridge made of Legos. One side has three support pieces, the other two. How would you stabilize the bridge? Most people would add a piece so that there are three supports on each side, a new study suggests. But why not remove a piece so that each side has two supports instead? It turns out that getting people to subtract — whether a Lego block, ingredients in a recipe or words in an essay — requires reminders and rewards, researchers report April 7 in Nature. This default to addition isn’t limited to assembling blocks, cooking and writing. Rather, thinking in pluses instead of minuses could well contribute to modern-day excesses such as cluttered homes, institutional red tape and even an overburdened planet, says behavioral scientist Benjamin Converse of the University of Virginia in Charlottesville. “We’re missing an entire class of solutions.” He and his colleagues first observed the behavior when they asked 1,585 study participants to tackle eight puzzles and problems that could be solved by adding or removing some things. For example, one puzzle required shading or erasing squares on a grid to make a pattern symmetric. In another, individuals could add or subtract items on a travel itinerary for the optimal experience. Across all experiments, the vast majority of participants chose addition over subtraction. For instance, out of 94 participants who completed the grid task, 73 added squares, 18 subtracted squares and another three simply reworked the original number of squares. The researchers hypothesized that most participants defaulted to adding because they failed to even think about subtraction. So, through a series of controlled experiments, the team nudged participants toward the minus sign.

4-8-21 AstraZeneca’s COVID-19 vaccine is tied to uncommon blood clots in rare cases
Because the cases are rare, the benefits of the shot still outweigh the risks, experts argue. In another hiccup for AstraZeneca’s COVID-19 vaccine, data suggest it is in fact linked to blood clots that have formed in the brains of some vaccinated people, the European Medicines Agency announced April 7. The blood clots are incredibly rare, EMA experts say. But because COVID-19 itself is deadly and can put people in the hospital, the benefits of the vaccine still outweigh the risks, they say. “We need to use the vaccines that we have to protect us from devastating effects” of COVID-19, Emer Cooke, executive director of the EMA, said in a news conference on April 7. The EMA had previously concluded that the vaccine, developed by AstraZeneca and the University of Oxford, was not linked to blood clots overall (SN: 3/18/21). But experts were uncertain about 18 case reports of blood clots in the sinuses that drain blood from the brain, a rare condition called cerebral venous sinus thrombosis or CVST. Enough data has now accrued to implicate the jab’s involvement in those rare blood clots, meaning CVST and similar conditions should be listed as a possible rare side effect of vaccination, the EMA’s Pharmacovigilance Risk Assessment Committee concluded after reviewing numerous cases reported in the United Kingdom and the European Union. As of March 22, countries had reported 62 cases of CVST out of around 25 million people who got the AstraZeneca vaccine. There were also 24 reported cases of clots in veins that drain blood from the digestive system, called splanchnic vein thrombosis or SVT. Eighteen of the people with CVST or SVT died. It’s still unknown how the vaccine could cause blood clots. One potential explanation is that some people develop an immune response that attacks platelets, making them clump together, Sabine Straus, chair of the EMA committee, said in the news conference. That would make the condition similar to low platelet levels and blood clots sparked by an immune response to the anticoagulant drug heparin. One preliminary study of four people who died from blood clots after vaccination had platelet-binding antibodies in their blood, researchers reported March 29 at Research Square, a preprint server. The study has not yet been reviewed by other scientists.

4-8-21 We can't let vaccines create bad incentives that make things worse
We are starting to vaccinate our way out of the pandemic, but we shouldn't let that make us complacent about the underlying problems, writes Graham Lawton. I RECEIVED the first dose of my covid-19 vaccine a couple of weeks ago, and it felt like a moment of liberation. By coincidence, it went into my arm on the anniversary of the announcement of the UK’s first national lockdown. As I write, we are eagerly anticipating the gradual lifting of the third such lockdown and the return of some freedoms: a walk with friends, a drink in the pub, a swim in a lido. The UK’s well-organised vaccine roll-out has played a huge part in bringing us to this point and we are indebted to the National Health Service – although unlike many of my fellow citizens, I am not prepared to forgive and forget the catalogue of inept and costly government decisions that necessitated a third lockdown in the first place. That aside, I am relieved to be brewing up my first batch of antibodies against the SARS-CoV-2 coronavirus (I assume that my sore arm and throbbing head were signs that my immune system was busy doing that). I also hope everyone who wants to be gets vaccinated soon. But at the same time, I am slightly alarmed at one of the unintended consequences of a hopefully successful global vaccination programme. The source of my alarm is something called moral hazard, which is a familiar concept in the world of climate change. This is the idea that well-intentioned attempts to reduce risk can create perverse incentives to take greater risks. For example, a person who is insured against house fires may be less careful with matches, knowing that if the worst happens the insurance company will pick up the pieces. Don’t get me wrong: I am wholly in favour of covid-19 vaccination. It is the only viable exit strategy from the pandemic and, despite the feverish fantasies of some self-appointed covid-19 sceptics, environmentalists like me don’t wish for perpetual lockdown. So bear with me.

4-8-21 'Exciting' Stone Age discoveries in the Cairngorms
New research has uncovered rare evidence of people living in Scotland's mountains after the end of the last Ice Age. Archaeologists found stone tools and traces of firepits and possible shelters in Deeside in the Cairngorms. Finds from the Mesolithic period, also known as the Middle Stone Age, are rare and usually made in lowland areas. Archaeologists describe the evidence in the Cairngorms as "exciting". The research, published in the Proceedings of the Prehistoric Society, adds to existing evidence from a handful of other upland sites. These include on the mountain Ben Lawers in Perthshire and at locations in Lanarkshire and Dumfries. Evidence for those who lived in Scotland after the end of the last Ice Age about 10,000 years ago can be hard to find, say archaeologists. The population at the time was low and the communities of hunter-gatherers were "mobile, moving around and living off the land". They did not build permanent monuments and their homes were usually temporary. What traces of their lives that can be found often amounts to a handful of tiny stone tools, such as flints, and discoloured soil "that hint at an ancient hearth or the stance of a shelter". Because this evidence has long been buried over time, the "easiest" locations for archaeologists to search are along sea-eroded coastlines or on farmland where farm work can bring buried the evidence closer to the surface. While archaeologists have long suspected Mesolithic communities occupied mountain landscapes, little evidence to support that has been discovered. Now a team made up of students from the universities of Aberdeen and Dublin has uncovered evidence confirming people were living in the Cairngorms from as early as 7500 BC. The team's finds at several archaeological sites - including traces of firepits, flints and possible huts - were made on land owned by the National Trust for Scotland (NTS).

4-8-21 Europe’s oldest known humans mated with Neandertals surprisingly often
The two species regularly interbred by about 45,000 years ago. When some of the earliest human migrants to Europe encountered Neandertals already living there around 45,000 years ago, hookups flourished. Analyses of DNA found in human fossils from around that time — the oldest known human remains in Europe — suggest that interbreeding between Homo sapiens and Neandertals, who were on the fast track to extinction, occurred more commonly than has often been assumed, two new studies suggest. Both reports appear April 7 in Nature Ecology & Evolution. Genetic evidence in the new reports indicates for the first time that distinct human populations reached Europe shortly after 50,000 years ago. Neandertals interbred with all the groups detected so far, ensuring that some of their genes live on today in our DNA. Remains of three H. sapiens individuals unearthed in Bulgaria’s Bacho Kiro Cave yielded nuclear DNA containing Neandertal contributions of about 3 to 4 percent, says a team led by evolutionary geneticist Mateja Hajdinjak of the Francis Crick Institute in London. The ancient DNA came from a tooth and two bone fragments radiocarbon dated to between around 43,000 and 46,000 years ago. Stone tools typical of late Stone Age humans were found in the same sediment as the fossils. “All of the Bacho Kiro individuals had recent Neandertal ancestors, as few as five to seven generations back in their family trees,” Hajdinjak says. Further evidence of ancient interbreeding comes from a nearly complete human skull discovered in 1950 in a cave in what’s now the Czech Republic. About 2 percent of the genes in DNA from that fossil, identified as a female’s, also come from Neandertals, say evolutionary geneticist Kay Prüfer of the Max Planck Institute for the Science of Human History in Jena, Germany, and his colleagues. Analysis of those DNA segments suggest she also lived around 45,000 years ago.

4-7-21 Why the UK changed covid-19 AstraZeneca vaccine advice for under-30s
On 7 April, the UK effectively restricted use of the Oxford/AstraZeneca covid-19 vaccine to people aged 30 and over because of the risk of a rare blood clot syndrome. But other European countries and Canada have broader restrictions, with higher age cut-offs. Why are the regulations different, and what are the implications for vaccine roll-out in the UK? What are the safety concerns over the Oxford/AstraZeneca vaccine? UK and European medicines regulators have been reviewing a small number of people who developed blood clots linked with low levels of platelets – small particles in the blood that normally help in clotting – soon after having the Oxford/AstraZeneca vaccine. Both have now concluded that the clots are possibly caused by the vaccine, although they say the benefits of vaccination for most people outweigh the risks. How should people under 30 weigh the benefits and drawbacks? For healthy people under 30, the health risks from catching covid-19 are low, but there may be a slightly higher rate of the blood clot condition in younger people. So, the UK Joint Committee on Vaccination and Immunisation (JCVI) has said the risk-benefit equation is “more finely balanced” for this group. That means that for people under 30, the chance of the vaccine causing the clotting reaction is a little greater than the risk of severe illness from covid-19. Why are other countries setting the age limit higher? Canada and France have restricted the Oxford/AstraZeneca jab to people 55 and over, while Germany has set the bar at 60, and Iceland 70. These countries seem to have taken a more cautious, broad-brush approach, reasoning that the blood clots have generally been seen in middle-aged people so the vaccine should be withheld below a certain age until we know more. The JCVI, by contrast, today announced results of a detailed analysis, comparing the risk of the suspicious blood clots with the risk of getting badly ill from covid-19 for every age group in 10-year bands. This is why the committee set the age limit at 30.

4-7-21 People are bad at spotting simple solutions to problems
Leonardo da Vinci said that a poet recognises perfection when there is nothing left to remove. In other words, less is more. But when solving problems, people tend to think the other way, adding elements rather than removing them. Gabrielle Adams at the University of Virginia and colleagues asked people to complete several tasks where solutions involved either adding or subtracting parts. All of the experiments were designed so that subtraction would be one of the most efficient options. In one, around 200 people had to alter a Lego building to support a weight in order to gain a $1 bonus. The roof of the building was balancing precariously on just one support. A solution would be to add several bricks to better support the roof, which they were told would cost 10 cents each. Another way of shoring up the structure was to simply remove one brick. Only 41 per cent of the control group opted to remove a brick, but when another group was prompted that removing bricks incurred no cost, this rose to 61 per cent. The team didn’t collect any demographic data for this part of the test. In another task, around 300 people had to make a grid of 100 squares symmetrical by either adding or removing green tiles. When asked to take the test with no practice, only 49 per cent of people opted to remove tiles, but when given three practice runs before taking the test, this rose to 63 per cent. In this test, just over 40 per cent of participants were women. During the research, the team spoke to a company with a newly appointed leader who asked staff for improvement suggestions. For every idea to remove a policy or rule, the leader received eight to add one. In a pre-prepared Q&A, Adams said that balance bikes are a great example of the subtractive approach. “These are kids’ bikes without the pedals or the chain. Most people who have seen a toddler zipping down the street on a balance bike instantly recognise that subtractive invention as superior to the clunky additive change of training wheels.”

4-7-21 Dementia risk doubles if people have both vision and hearing loss
Older adults who start losing both vision and hearing may be at an increased risk of developing dementia. Gihwan Byeon at Kangwon National University Hospital in South Korea and his colleagues studied 6520 people, aged 58 to 101, over six years. At the start of the study, they asked each person to rate their ability to see and hear. The participants also underwent cognitive testing every two years. The team found that 7.6 per cent of those reporting both vision and hearing loss had dementia at the start of the study, and another 7.4 per cent developed it within six years. Meanwhile, only 2.4 per cent of people with only vision or hearing loss had dementia at the start of the study, and another 2.9 per cent developed it by the end of the study. Adjusting for other factors that influence dementia, such as sex, education and income, the researchers estimate that people with impairments of both vision and hearing are twice as likely to develop dementia as people with only one or neither impairment. The results are “very tantalising”, says Jason Warren at University College London. However, the findings must be considered with caution, he adds, as the hearing and vision loss were self-reported rather than measured directly. Even so, this could provide insight into the cognitive decline that people with hearing and vision loss experience, says Warren. “We see and hear with our brains, and the first sign of a failing brain in dementia may well be an inability to navigate the complex sensory environments of everyday life,” he says. Byeon wonders whether the brains of people with both hearing and vision loss might struggle to compensate for the lost senses. Usually, people with impaired vision develop better hearing to compensate, and people with impaired hearing rely more on their vision to help out, he says. “Dual sensory impairment may not be compensated for, making [the brain] more vulnerable to dementia,” he says.

4-7-21 Experimental events offer glimpse of safe, post-lockdown nightlife
FOR a few hours on a Saturday afternoon in March, Simone van Erp did what, for much of the planet right now, would be unthinkable. She took off her mask, brushed up against strangers, danced, sang and shouted as loud as she could – droplets and aerosols be damned – as DJs at the Ziggo Dome in Amsterdam, the Netherlands, spun to a rapturous crowd of 1300. “Everyone was really happy, enthusiastic, screaming and laughing, it was crazy,” says van Erp. “It was a good feeling. You could see that everyone missed normal life.” It has been a year since much of the world has been able to dance and sing in a hot, crowded venue. Now studies are offering clues as to how we can safely reintroduce large gatherings into our lives. During the early days of the coronavirus pandemic, it became clear that mass gatherings can be superspreader events, where just a few infected people can spark a large outbreak. In February 2020, before lockdowns began in the US, a two-day conference in Boston with 175 attendees was identified as the source of an estimated 20,000 cases of covid-19 across the Boston area by May. Now, with mass vaccinations gathering pace globally, while the live entertainment sector typically remains hamstrung, many nations are conducting research with the goal of bringing back large events. France is planning to conduct experimental stadium concerts in Paris and Marseille. So far, about 2000 students with no underlying health risks have been enlisted to attend two separate concerts in Marseille organised by the French National Institute of Health and Medical Research. Attendees will be tested the day before the event, but not told their result to allow for the presence of infected individuals. Concertgoers will wear surgical grade N95 masks and be required to socially distance. The goal is to look at the transmission rates of infected people when safety measures are in place. Attendees will be tested for the two weeks after the event. The results will also be compared with a control group of 1000 people who won’t be at either concert.

4-7-21 Why the UK changed covid-19 AstraZeneca vaccine advice for under-30s
On 7 April, the UK effectively restricted use of the Oxford/AstraZeneca covid-19 vaccine to people aged 30 and over because of the risk of a rare blood clot syndrome. But other European countries and Canada have broader restrictions, with higher age cut-offs. Why are the regulations different, and what are the implications for vaccine roll-out in the UK? What are the safety concerns over the Oxford/AstraZeneca vaccine? UK and European medicines regulators have been reviewing a small number of people who developed blood clots linked with low levels of platelets – small particles in the blood that normally help in clotting – soon after having the Oxford/AstraZeneca vaccine. Both have now concluded that the clots are possibly caused by the vaccine, although they say the benefits of vaccination for most people outweigh the risks. How should people under 30 weigh the benefits and drawbacks? For healthy people under 30, the health risks from catching covid-19 are low, but there may be a slightly higher rate of the blood clot condition in younger people. So, the UK Joint Committee on Vaccination and Immunisation (JCVI) has said the risk-benefit equation is “more finely balanced” for this group. That means that for people under 30, the chance of the vaccine causing the clotting reaction is a little greater than the risk of severe illness from covid-19. Why are other countries setting the age limit higher? Canada and France have restricted the Oxford/AstraZeneca jab to people 55 and over, while Germany has set the bar at 60, and Iceland 70. These countries seem to have taken a more cautious, broad-brush approach, reasoning that the blood clots have generally been seen in middle-aged people so the vaccine should be withheld below a certain age until we know more. The JCVI, by contrast, today announced results of a detailed analysis, comparing the risk of the suspicious blood clots with the risk of getting badly ill from covid-19 for every age group in 10-year bands. This is why the committee set the age limit at 30.

4-5-21 New depictions of ancient hominids aim to overcome artistic biases
Reconstructions based on intuition can distort views of what extinct species looked like. Depictions of extinct human ancestors and cousins are often more art than science. Take, for example, two reconstructions of the Taung child, a 2.8-million-year-old Australopithecus africanus skull discovered in South Africa in 1924. One version, made using a sculptor’s intuition, appears more apelike. A second version, made while working alongside a scientist, appears more humanlike. Now, the researchers that produced the dueling images are attempting to remove some of this subjectivity by introducing standards that may give more accurate and reproducible portraits of species known only from fossilized bone. The team points out some of the flaws in facial reconstructions of ancient hominids — and the social and ethical implications misleading portraits may have — in a report published February 26 in Frontiers in Ecology and Evolution. Getting the depictions right matters, says Rui Diogo, a biological anthropologist at Howard University in Washington, D.C. When museumgoers see artists’ renditions of Neandertals or extinct hominids, visitors often don’t realize how much bias creeps into the work. “They think it is reality,” he says. And that can skew people’s views and reinforce existing prejudices of present-day people. For instance, reconstructions of multiple extinct hominids in the Smithsonian National Museum of Natural History in Washington, D.C., portray skin getting lighter and lighter in color as species became more and more bipedal. “But there is zero evidence to say the skin was whiter,” Diogo says. Such a depiction might give the mistaken impression that people with lighter skin are more evolved. Artists’ depictions can also give erroneous views of human evolution and extinct species’ intelligence and behavior, says Diogo’s coauthor Ryan Campbell, an anatomical scientist and physical anthropologist at the University of Adelaide in Australia. For instance, Neandertals are often portrayed as having matted, dirty hair. “It’s as if there is a bias toward portraying our ancestors as if they were stupid and didn’t have hygiene,” he says.

4-5-21 Stingrays in the Amazon were stranded there by the Caribbean Sea
The web of waterways draining out of tropical regions of South America is home to dozens of species of freshwater stingrays. The fish evolved from seagoing ancestors, but exactly how they got inland has always been unclear. Now it seems they were carried by the Caribbean Sea reaching deep into the continent millions of years ago. Central and South America are home to about 20 per cent of the world’s total fish species, says João Pedro Fontenelle at the University of Toronto in Canada. Intrigued by what could be responsible for this biodiversity, Fontenelle and his colleagues looked to the evolutionary history of river stingrays, which are only found in South America. There are 38 species, most with spots or marble patterns, and they range in size from 25 centimetres to more than a metre across. The stingrays are also the only exclusively freshwater lineage of shark or ray alive today. The researchers analysed DNA from 350 individual stingrays across 35 different species. By comparing genetic differences between species, they determined how the stingrays split into many species over time, giving insight into where and when they first left the sea. Fontenelle and his team estimate that the river stingrays diverged from their ocean relatives around 26 million years ago, between the Oligocene and Miocene epochs, in the upper Amazon basin. Back then, this area looked quite different from the dense rainforest present today. “The sea level was higher than it is today and the Andes were not that high, and we had a nice lowland formation on the western portion of the Amazon,” says Fontenelle. “That allowed for the sea to come into the continent.” Fossil and chemical evidence in rock suggests the northwestern corner of South America was dominated by a vast, swampy sea for millions of years. Known as the Pebas wetlands, they may have stretched as far south as Argentina.

4-4-21 The nature photography project for London health care workers
Liz Hingley started the "Nature of Care" project 10 months ago to helps nurses and doctors in London cope with pandemic-induced stress and anxiety by teaching them nature photography skills. his project — "Nature of Care" — started with a dream. Not a figurative, hopes-for-a-better-world kind of dream, but the middle of the night, vivid, outlandish variety of dream. When British photographer Liz Hingley's sleep was interrupted during the first coronavirus lockdown in 2020, she dreamed that nurses and doctors came streaming out of London's big hospitals, all dressed in masks and protective gear and began embracing trees — hugging them. "They were kind of socially distanced, hugging their tree with their hazmat suits on or face masks," Hingley told The World's host, Marco Werman. Hingley could not get the images from her nature dream out of her mind. She described the visuals in her dream as visceral. The next morning, she felt like she had to do something about it. "In my mind, when I woke up, I was like, I have to make that picture," Hingley said. "And then, I obviously realized after a coffee that I probably wasn't able to make that picture. But then I translated it into this project that I've been running almost for 10 months now." Below, Hingley talks with The World about her photography project and how it has offered weary health care providers a fresh perspective on life. Marco Werman: So, you know a lot about photography and about the world that can open up to people. What did you set out to do then with health care providers, two of London's largest hospitals after you had this dream? Liz Hingley: I'm really lucky to live next to a place called Hampstead Heath, which is a huge, kind of green area, that was given to the city of London — to the people in the city of London — 150 years ago this year. And during that time, I was doing my sort of one-hour lockdown exercise and walking on the Heath and so aware of what a healing resource this place was for me and for so many people during that really confusing time. And there's an area on the Heath where there's two of London's largest hospitals to either side of the city. I just kind of called them up cold and said, can I run some photography walks on the Heath for any stuff? And wonderfully, both hospitals responded positively. And I had no idea what the uptake would be, but it was kind of overwhelming. So, just to be clear, you kind of gave them the training and then they went out with their cameras and started taking photographs. Yeah, I managed to convince Canon to sponsor me because I was keen that they should be free. And that also people should have the ability to learn a little bit of photography, but also make some really stunning images. And the aim of the project, it was to really take people away from the workplace and the crisis conditions in the hospital. And, allow them to connect with local nature that was just on their doorstep and develop a practice potentially using photography as seeing more deeply and reconnecting, in a way, just in lunch breaks and short periods. I didn't label it as therapy. One thing that stuck with me when I first contacted the hospitals was that the head of staff in the Whittington Hospital in London said that staff, particularly critical care staff — so those at the really at the front-line intensive care — really rarely seek help. But what they always look for and respond to is the chance to relax. So, for many people, I guess the experience is very difficult to put into words and to communicate to others who have no idea what the environment is like. But being out and walking and physically being constructive and doing something with your body and also producing something at the same time, can feel quite constructive in a way of processing and expressing without putting things into words.

4-3-21 Sounding the alarm: How noise hurts the heart
Scientists are uncovering new details about how what you hear stresses the cardiovascular system. n 2011, Germany's Frankfurt Airport — the country's busiest — unveiled its fourth runway. The addition sparked major protests, with demonstrators returning to the airport every Monday for years. "It's destroying my life," one protester told Reuters a year later. "Every time I go into my garden, all I can hear and see are planes right above." The new runway also channeled dozens of aircraft directly over the house of Thomas Münzel, a cardiologist at the University Medical Center of Mainz. "I have lived close to the German Autobahn and close to inner city train tracks," he says. "Aircraft noise is the most annoying by far." Münzel had read a 2009 World Health Organization report linking noise to heart problems, but evidence at the time was thin. Driven in part by concern for his own health, in 2011 he shifted the focus of his research to learn more. Exposure to loud noise has long been linked with hearing loss. But the ruckus of planes and cars takes a toll beyond the ears: Traffic noise has been flagged as a major physiological stressor, second to air pollution and on roughly equal footing with exposure to secondhand smoke and radon. In the last decade, a growing body of research more directly links air and road traffic noise to a heightened risk for a number of cardiovascular ailments — and scientists are beginning to pinpoint the mechanisms at play. Evidence of noise's physiological effects — whether on cells and organs or entire populations — "is really coming together and painting a picture of the problem," says Mathias Basner, a psychiatrist and epidemiologist at the University of Pennsylvania and president of the International Commission on the Biological Effects of Noise. Yet, he adds, few people are aware of the severity of what his colleagues refer to as a "silent killer." Estimates suggest that roughly a third of Europeans and Americans are regularly exposed to unhealthy levels of noise, typically defined as starting around 70 to 80 decibels. For comparison, normal conversation is typically about 60 dB, cars and trucks range around 70 to 90 dB, and sirens and airplanes can reach 120 dB or more. Numerous studies link chronic exposure to such environmental noise to an increased risk of heart-related troubles. People living near the Frankfurt Airport, for example, have as much as a 7 percent higher risk of stroke than those living in similar but quieter neighborhoods, according to a 2018 study in Noise & Health that investigated health data of more than 1 million people. An analysis of nearly 25,000 cardiovascular deaths between 2000 and 2015 among people living near Switzerland's Zurich Airport saw significant increases in nighttime mortality after airplane flyovers, especially among women, a team reported last year in the European Heart Journal. As researchers probe the physiology underlying noise's cardiovascular consequences, they are zeroing in on a culprit: dramatic changes to the endothelium, the inner lining of arteries and blood vessels. This lining can go from a healthy state to one that's "activated," and inflamed, with potentially serious ramifications. The path from noise to blood vessels goes something like this: When sound reaches the brain, it activates two important regions: the auditory cortex, which interprets noise, and the amygdala, which manages emotional responses to it. As noise gets louder, and especially during sleep, the amygdala activates the body's flight-or-fight response — even if the person isn't aware of it.

4-3-21 Dinosaur-killing asteroid strike gave rise to Amazon rainforest
The asteroid impact that killed off the dinosaurs gave birth to our planet's tropical rainforests, a study suggests. Researchers used fossil pollen and leaves from Colombia to investigate how the impact changed South American tropical forests. After the 12km-wide space rock struck Earth 66 million years ago, the type of vegetation that made up these forests changed drastically. The team has outlined its findings in the prestigious journal Science. Co-author Dr Mónica Carvalho, from the Smithsonian Tropical Research Institution in Panama, said: "Our team examined over 50,000 fossil pollen records and more than 6,000 leaf fossils from before and after the impact." They found that cone-bearing plants called conifers and ferns were common before the huge asteroid struck what is now the Yucatan Peninsula in Mexico. But after the devastating impact, plant diversity declined by roughly 45% and extinctions were widespread, particularly among seed-bearing plants. While the forests recovered over the next six million years, angiosperms, or flowering plants, came to dominate them. The structure of tropical forests also changed as a result of this transition. During the late Cretaceous Period, when the dinosaurs were still alive, the trees that made up the forests were widely-spaced. The top parts did not overlap, leaving open sunlit areas on the forest floor. But post-impact, forests developed a thick canopy that allowed much less light to reach the ground. So how did the impact transform the sparse, conifer-rich tropical forests of the dinosaur age into the rainforests of today, with their towering trees dotted with multi-coloured blossoms and orchids? Based on their analysis of the pollen and leaves, the researchers propose three different explanations. Firstly, dinosaurs could have kept the forest from growing too dense by feeding on and trampling plants growing in the lower levels of the forest. A second explanation is that falling ash from the impact enriched soils throughout the tropics, giving an advantage to faster-growing flowering plants. The third explanation is that the preferential extinction of conifer species created an opportunity for flowering plants to take over.

4-2-21 Bronze Age dogs ate little meat and had to feed on cereals instead
Many early domestic dogs ate almost no meat. Dogs living around 3000 years ago in what is now Spain were instead fed cereals, such as millet, by their owners. Although the diet may reflect the fact that meat was relatively scarce among human societies at the time, feeding dogs with cereals could have been advantageous, says Silvia Albizuri at the University of Barcelona in Spain. It may have been a way to ensure the dogs had plenty of energy for the strenuous work of herding and guarding livestock, she says, particularly since these dogs “were not pets as we conceive them nowadays”. Dogs were domesticated from wolves in Europe and Asia within the past 40,000 years. Wolves are carnivores, getting most of their nutrition from meat. Albizuri and her colleagues studied the remains of 36 dogs from Can Roqueta, an archaeological site near Barcelona. It lies on a plain near the coast and was inhabited from the Stone Age onwards. The dogs lived in the Bronze Age and Iron Age, between 1300 and 550 BC, and had been buried in pits. The researchers obtained protein from the dogs’ bones and focused on the carbon and nitrogen atoms in the samples, each of which exist in two forms called isotopes. Different foods have varying ratios of carbon and nitrogen isotopes, and this influences the makeup of the protein – so studying the isotopes in the protein gives an indication of what the animals ate. The dogs’ diets differed considerably. While nine of them ate plenty of meat and 10 were omnivorous, the rest ate mostly plants – and some had isotope ratios that could barely be distinguished from those of the cattle they once guarded. The finding adds to the evidence that many early domestic dogs ate little meat, says Albizuri. This trend began with the advent of farming. “When human societies began to domesticate plants during the Neolithic period, hunting decreased and the human diet was based mainly on vegetables,” she says. “Dogs began to be fed on plants, mainly cereals.”

4-2-21 The dinosaur-killing asteroid impact radically altered Earth’s tropical forests
Sun-laden, open-canopied forests were transformed into the dark, dense ones seen today. The day before a giant asteroid hit Earth 66 million years ago, a very different kind of rainforest thrived in what is now Colombia. Ferns unfurled and flowering shrubs bathed in the sunlight that streamed down through large gaps in the canopy between towering conifers. Then the bolide hit and everything changed (SN: 6/1/20). That impact not only set off a massive extinction event that wiped out more than 75 percent of life on Earth, but it also redefined Earth’s tropical rainforests, transforming them from sun-dappled, open-canopied forests into the dark, dense, lush, dripping forests of today’s Amazon, researchers report April 2 in Science. The researchers analyzed tens of thousands of fossils of pollen, spores and leaves, collected from 39 sites across Colombia, that were dated to between 70 million and 56 million years ago. The team then assessed overall forest plant diversity, dominant species and insect-plant interactions, and tracked how these factors shifted. Plant diversity declined by 45 percent in the immediate aftermath of the asteroid strike, the researchers found, and it took 6 million years before the rich diversity of the tropical rainforest rebounded. Even then, the forests were never the same. “A single historical accident changed the ecological and evolutionary trajectory of tropical rainforests,” says Carlos Jaramillo, a paleopalynologist — someone who studies ancient pollen — at the Smithsonian Tropical Research Institute in Panama City. “The forests that we have today are really the by-product of what happened 66 million years ago.” Just before the extinction event, tropical forests were a roughly 50-50 mix of angiosperms, or flowering trees and shrubs, and of other plant species such as conifers and ferns. “The competition for light was not that intense,” Jaramillo says. Afterward, ferns and conifers largely vanished, and angiosperms took over to make up about 90 percent of the plant species in the forest.

4-1-21 Asteroid that killed the dinosaurs gave birth to the Amazon rainforest
Today’s tropical rainforests came about because of the huge asteroid strike thought to have wiped out the dinosaurs. Before the asteroid hit the Yucatán peninsula in what is now Mexico, South America’s rainforests were made up of vastly different greenery than the abundance of flowering plants they now contain. “If you returned to the day before the meteorite fall, the forest would have an open canopy with a lot of ferns, many conifers and dinosaurs,” says Carlos Jaramillo at the Smithsonian Tropical Research Institute in Panama. “The forest we have today is the product of one event 66 million years ago.” Jaramillo and his colleagues analysed tens of thousands of samples of fossilised pollen and leaves found in northern South America that dated to the part of the Cretaceous period just before the asteroid hit, and just after the impact, in the Palaeocene epoch. They found that plant diversity declined by 45 per cent after the impact and took 6 million years to recover. Insect bites on fossilised leaves showed that insect diversity also took a nosedive. The rainforests of South America changed in the aftermath of the catastrophe. Most of the cone-bearing plants and ferns disappeared, and the rainforests became dominated by flowering plants called angiosperms. A thick canopy allowed only a little light to reach the ground. “I think the number one lesson here is unpredictability,” says Ellen Currano at the University of Wyoming. “When you have these major perturbations, they change the rules of the whole ecosystem.” Jaramillo and his colleagues suggest there are several reasons why the asteroid may have caused this major change. For one, the impact probably killed most of the large, herbivorous dinosaurs that once trampled down and ate the lower levels of the forests.

4-1-21 Animal culture is so common that even fish and flies have it
Culture was once thought to be restricted to humans. But we are discovering more and more examples in animals. In a paper reviewing evidence from several earlier studies that is published in Science this week, zoologist Andrew Whiten at the University of St Andrews, UK, writes that there has been “an explosion of discoveries” showing that animal culture is far more widespread and diverse than we imagined. New Scientist quizzed him about the work. Michael Le Page: Many readers will know that apes and whales have culture, such as tool use in chimpanzees, but you say that even insects have it. Andrew Whiten: That is the big surprise. The evidence was really just published in the last few years. So some of us are still reeling from that and thinking, “Well, wow, culture is everywhere.” It’s the reach of animal culture across an increasing range of species that’s one of the main points of my paper. Can you give an example of insect culture? There’s good evidence for what’s called mate choice copying in fruit flies. So if female fruit flies watch a male who’s been dusted green by experimenters mate with a female, later on, if given a choice, those females will prefer green-dusted males. The virgin females are learning, “If all the girls like this kind of chap, he must be a good one to go for.” The reason that you can talk about cultural transmission is that if other females watch those females mating, they inherit that same bias, and so on. It is like an incipient tradition. In bumblebees there are examples of particular foraging techniques that again pass from bumblebee to bumblebee to bumblebee. What exactly do researchers mean by animal culture? It is basically behaviour that is passed from one individual to another, spreads across a group and becomes a group characteristic. It may be passed down many generations.

4-1-21 4 takeaways from the WHO’s report on the origins of the coronavirus
The leading hypothesis is it spread to people from bats via a yet-to-be-identified animal. A new World Health Organization report investigating the origins of the coronavirus has raised more questions than answers for how — and where — the virus that exploded into a global pandemic emerged. The report, released March 30, tallies where the evidence currently points: The virus, called SARS-CoV-2, probably jumped to people from bats through another animal; it likely did not come from a lab. But officials can’t yet prove — or rule out — any scenario. And questions about just how much access to potential evidence an international team of experts had on their 28-day trip to Wuhan, China, in January and February has cast a shadow on the findings. On that trip, 17 experts with the WHO teamed up with 17 Chinese scientists to assess four potential scenarios for the origins of the coronavirus. The two leading scenarios, the team concluded, are transmission of the virus to people either directly from bats or, more likely, via an intermediate animal like a civet or raccoon dog. A third possibility is the virus got to people through contaminated frozen food products, which the team considers less likely but says merits further investigation. The last scenario — that the virus began spreading among people following a lab accident — is “extremely unlikely,” the researchers wrote. In a joint statement on March 30, 14 countries including the United States expressed concern that the WHO team was delayed and didn’t have access to original data and samples from people and animals. That reaction comes amid reports that the Chinese government had a hand in the mission, controlling the sites the team accessed during the visit and the report’s wording. “Scientific missions like these should be able to do their work under conditions that produce independent and objective recommendations and findings,” the countries wrote in the statement.

4-1-21 Pfizer says its COVID-19 vaccine has 100 percent efficacy in young people
None of the vaccinated 12- to 15-year-olds had symptoms and the shot’s side effects were mild. Pfizer and BioNTech’s COVID-19 vaccine proved highly effective in adults. Now it appears to work well in younger people too. In a Phase III clinical trial of 12- to 15-year-olds, participants who received the shot developed higher levels of antibodies to the coronavirus on average compared with vaccinated 16- to 25-year-olds from a previous trial (SN: 11/18/20). And those antibody levels make for a vaccine with high efficacy. None of the 1,131 vaccinated teens developed COVID-19 symptoms. There were 18 cases among the 1,129 youths in the unvaccinated group, Pfizer reported in a March 31 news release. That 100 percent efficacy, based on a small number of cases overall, could decrease a bit as the trial continues because additional cases might pop up. Still, the results point to a vaccine that works well in adolescents. The news is “astounding and very exciting,” Colleen Kelley, an infectious diseases physician at Emory University in Atlanta who helped lead a trial of Moderna’s COVID-19 vaccine, said in a call with reporters. Though Pfizer has not yet released all the data from the trial, protecting adolescents “will go a long way to end the pandemic,” she said. That’s because kids younger than 12 appear to be less likely than older kids to get infected with the coronavirus and pass it on to others. The shot’s side effects in the 12- to 15-year-olds were similar to those seen in the 16- to 25-year-old age group, the company said. The most common side effect in the older participants was pain at the injection site, followed by fatigue and headache. Pfizer plans to submit the data to the U.S. Food and Drug Administration, as well as the European Medicines Agency, as soon as possible to ask that its emergency use authorizations be altered so that vaccinations can be expanded to those 12 and older.

4-1-21 Frog skin cells turned themselves into living machines
Newly created ‘xenobots’ swim and move particles around in their environment. Using blobs of skin cells from frog embryos, scientists have grown creatures unlike anything else on Earth, a new study reports. These microscopic “living machines” can swim, sweep up debris and heal themselves after a gash. Scientists often strive to understand the world as it exists, says Jacob Foster, a collective intelligence researcher at UCLA not involved with this research. But the new study, published March 31 in Science Robotics, is part of a “liberating moment in the history of science,” Foster says. “A reorientation towards what is possible.” In a way, the bots were self-made. Scientists removed small clumps of skin stem cells from frog embryos, to see what these cells would do on their own. Separated from their usual spots in a growing frog embryo, the cells organized themselves into balls and grew. About three days later, the clusters, called xenobots, began to swim. Normally, hairlike structures called cilia on frog skin repel pathogens and spread mucus around. But on the xenobots, cilia allowed them to motor around. That surprising development “is a great example of life reusing what’s at hand,” says study coauthor Michael Levin, a biologist at Tufts University in Medford, Mass. And that process happens fast. “This isn’t some sort of effect where evolution has found a new use over hundreds of thousands of years,” Levin says. “This happens in front of your eyes within two or three days.” Xenobots have no nerve cells and no brains. Yet xenobots — each about half a millimeter wide — can swim through very thin tubes and traverse curvy mazes. When put into an arena littered with small particles of iron oxide, the xenobots can sweep the debris into piles. Xenobots can even heal themselves; after being cut, the bots zipper themselves back into their spherical shapes.

4-1-21 Stone Age culture bloomed inland, not just along Africa’s coasts
Excavations at a rock-shelter inhabited 105,000 years ago turned up possibly symbolic crystals. Africa’s southern Kalahari Desert is not typically regarded as a hotbed of Stone Age innovations. And yet human culture blossomed there around 105,000 years ago, back when it was green, researchers say. Calcite crystals and other finds at a South African rock-shelter more than 600 kilometers from the nearest shoreline reflect cultural behaviors on a par with those previously reported for ancient humans living on or near South Africa’s coast, researchers report March 31 in Nature. Those coastal sites date to between roughly 125,000 and 70,000 years ago, including one where locals used tools to make paint out of pigment around 100,000 years ago (SN: 10/13/11). Given the scarcity of human sites from that time period, it’s hard to know whether cultural innovations emerged independently in groups spread across southern Africa or originated in one particular region before being adopted elsewhere. But the new discoveries fit a scenario in which “the emergence of Homo sapiens involved the interaction of many different populations across Africa,” says archaeologist Jayne Wilkins of Griffith University in Nathan, Australia. “And that included the Kalahari Desert.” Excavations at Ga-Mohana Hill North Rockshelter, or GHN, uncovered an ancient sediment layer containing 42 burned ostrich eggshell fragments and 22 palm-sized or smaller calcite crystals, Wilkins and her colleagues report. Like some African hunter-gatherer groups today, ancient people at GHN may have cut holes out of ostrich eggshells to create water containers, the researchers say. Geologic studies indicated that enough rain once fell over the southern Kalahari Desert to have produced year-round water sources for ancient GHN people.

28 Evolution News Articles
for April 2021

Evolution News Articles for March 2021