New superhighway system discovered in the Solar System

 

Stylized illustration of Solar System.

Researchers have discovered a new superhighway network to travel through the Solar System much faster than was previously possible. Such routes can drive comets and asteroids near Jupiter to Neptune's distance in under a decade and to 100 astronomical units in less than a century. They could be used to send spacecraft to the far reaches of our planetary system relatively fast, and to monitor and understand near-Earth objects that might collide with our planet.

In their paper, published in the Nov. 25 issue of Science Advances, the researchers observed the dynamical structure of these routes, forming a connected series of arches inside what's known as space manifolds that extend from the asteroid belt to Uranus and beyond. This newly discovered "celestial autobahn" or "celestial highway" acts over several decades, as opposed to the hundreds of thousands or millions of years that usually characterize Solar System dynamics.

The most conspicuous arch structures are linked to Jupiter and the strong gravitational forces it exerts. The population of Jupiter-family comets (comets having orbital periods of 20 years) as well as small-size solar system bodies known as Centaurs, are controlled by such manifolds on unprecedented time scales. Some of these bodies will end up colliding with Jupiter or being ejected from the Solar System.

The structures were resolved by gathering numerical data about millions of orbits in our Solar System and computing how these orbits fit within already-known space manifolds. The results need to be studied further, both to determine how they could be used by spacecraft, or how such manifolds behave in the vicinity of the Earth, controlling the asteroid and meteorite encounters, as well as the growing population of artificial human-made objects in the Earth-Moon system.

From Science Daily

Neanderthals buried their dead: New evidence

 

Illustration of prehistoric people.

Was burial of the dead practiced by Neandertals or is it an innovation specific to our species? There are indications in favour of the first hypothesis but some scientists remain sceptical. For the first time in Europe, however, a multi-disciplinary team led by researchers at the CNRS and the Muséum national d'histoire naturelle (France) and the University of the Basque Country (Spain) (1) has demonstrated, using a variety of criteria, that a Neandertal child was buried, probably around 41,000 years ago, at the Ferrassie site (Dordogne). Their study is published in the journal Scientific Reports on 9th December 2020.

Dozens of buried Neandertal skeletons have been discovered in Eurasia, leading some scientists to deduce that, like us, Neandertals buried their dead. Other experts have been sceptical, however, given that the majority of the best-preserved skeletons, found at the beginning of the 20th century, were not excavated using modern archaeological techniques.

It is within this framework that an international team led by paleoanthropologists Antoine Balzeau (CNRS and Muséum national d'histoire naturelle, France) and Asier Gómez-Olivencia (University of the Basque Country, Spain), analysed a human skeleton from one of the most famous Neandertal sites in France: the La Ferrassie rock shelter, Dordogne. After six Neandertal skeletons were discovered at the beginning of the 20th century, the site delivered a seventh between 1970 and 1973, belonging to a child of around two years old. For almost half a century, the collections associated with this specimen remained unexploited in the archives of the Musée d'archéologie nationale.

Recently, a multidisciplinary team, assembled by the two researchers, reopened the excavation notebooks and reviewed the material, revealing 47 new human bones not identified during excavation and undoubtedly belonging to the same skeleton. The scientists also carried out a thorough analysis of the bones: state of preservation, study of proteins, genetics, dating, etc. They returned to La Ferrassie in the hope of finding further fragments of the skeleton; although no new bones were discovered, using the notebooks of their predecessors, they were able to reconstruct and interpret the spatial distribution of the human remains and the rare associated animal bones.

The researchers showed that the skeleton had been buried in a sedimentary layer which inclined to the west (the head, to the east, was higher than the pelvis), while the other stratigraphic layers of the site inclined to the north-east. The bones, which were relatively unscattered, had remained in their anatomical position. Their preservation, better than that of the bison and other herbivores found in the same stratum, indicates a rapid burial after death. Furthermore, the contents of this layer proved to be earlier than the surrounding sediment. Finally, a tiny bone, identified as human by the proteins and as Neandertal by its mitochondrial DNA, was directly dated using carbon-14. At around 41,000 years old, this makes it one of the most recent directly dated Neandertal remains.

Read more at Science Daily

Spiders in space: Without gravity, light becomes key to orientation

Spider web

Humans have taken spiders into space more than once to study the importance of gravity to their web-building. What originally began as a somewhat unsuccessful PR experiment for high school students has yielded the surprising insight that light plays a larger role in arachnid orientation than previously thought.

The spider experiment by the US space agency NASA is a lesson in the frustrating failures and happy accidents that sometimes lead to unexpected research findings. The question was relatively simple: on Earth, spiders build asymmetrical webs with the center displaced towards the upper edge. When resting, spiders sit with their head downwards because they can move towards freshly caught prey faster in the direction of gravity.

But what do arachnids do in zero gravity? In 2008, NASA wanted to inspire middle schools in the US with this experiment. But even though the question was simple, the planning and execution of the experiment in space was extremely challenging. This led to a number of mishaps.

Two specimens from different spider species flew to the International Space Station (ISS) as "arachnauts," one (Metepeira labyrinthea) as the lead and the other (Larinioides patagiatus) as a reserve in case the first didn't survive.

The reserve spider escaped

The reserve spider managed to break out of its storage chamber and into the main chamber. The chamber couldn't be opened for safety reasons, so the extra spider could not be recaptured. The two spiders spun somewhat muddled webs, getting in each other's way.

And if that were not enough, the flies included as food reproduced more quickly than expected. Over time, their larvae crawled out of the breeding container on the floor of the case into the experimental chamber, and after two weeks covered large parts of the front window. After a month, the spiders could no longer be seen behind all the fly larvae.

This failure long nagged at Paula Cushing of the Denver Museum of Nature & Science, who participated in the planning of the spider experiment. When the opportunity for a similar experiment on board the ISS cropped up again in 2011, the researcher got Dr. Samuel Zschokke of the University of Basel involved to prepare and analyze the new attempt. This time, the experiment started with four spiders of the same species (Trichonephila clavipes): two flew to the ISS in separate habitats, two stayed on Earth in separate habitats and were kept and observed under identical conditions as their fellows traveling in space -- except that they were exposed to terrestrial gravity.

The females were males

The plan was originally to use four females. But another mishap occurred: the spiders had to be chosen for the experiment as juveniles and it is extremely difficult to determine the sex of juvenile animals. In the course of the experiment, two of the spiders turned out to be males, which differ markedly in body structure and size from females of this species when fully grown. But finally there was a stroke of luck -- one of the males was on board the space station, the other on Earth.

The arachnids spun their webs, dismantled them, and spun new ones. Three cameras in each case took pictures every five minutes. Zschokke, Cushing and Stefanie Countryman of the University of Colorado's BioServe Space Technologies that oversaw the design and launch of the space flight certified habitats containing the spiders and fruit fly larvae and camera system to the International Space Station analyzed the symmetry of 100 spider webs and the orientation of the spider in the web using about 14,500 images.

It turned out that the webs built in zero gravity were indeed more symmetrical than those spun on Earth. Their center was closer to the middle and the spiders did not always keep their heads downwards. However, the researchers noticed that it made a difference whether the spiders built their webs in lamplight or in the dark. Webs built on the ISS in lamplight were similarly asymmetrical as the terrestrial webs.

Light as a back-up system

"We wouldn't have guessed that light would play a role in orienting the spiders in space," says Zschokke, who analyzed the spider experiment and published the results with his colleagues in the journal Science of Nature. "We were very fortunate that the lamps were attached at the top of the chamber and not on various sides. Otherwise, we would not have been able to discover the effect of light on the symmetry of webs in zero gravity."

Analysis of the pictures also showed that the spiders rested in arbitrary orientations in their webs when the lights were turned off, but oriented themselves away -- i.e. downwards -- when the lights were on. It seems spiders use light as an additional orientation aid when gravity is absent. Since spiders also build their webs in the dark and can catch prey without light, it had previously been assumed that light plays no role in their orientation.

Read more at Science Daily

Paleontologists find pterosaur precursors that fill a gap in early evolutionary history

 

Pterosaurs illustration.

Here's the original story of flight. Sorry, Wright Brothers, but this story began way before your time -- during the Age of the Dinosaurs.

Pterosaurs were the earliest reptiles to evolve powered flight, dominating the skies for 150 million years before their imminent extinction some 66 million years ago.

However, key details of their evolutionary origin and how they gained their ability to fly have remained a mystery; one that paleontologists have been trying to crack for the past 200 years. In order to learn more about their evolution and fill in a few gaps in the fossil record, it is imperative that their closest relatives are identified.

With the help of newly discovered skulls and skeletons that were unearthed in North America, Brazil, Argentina, and Madagascar in recent years, Virginia Tech researchers Sterling Nesbitt and Michelle Stocker from the Department of Geosciences in the College of Science have demonstrated that a group of "dinosaur precursors," called lagerpetids, are the closest relatives of pterosaurs.

"Where did pterosaurs come from?' is one of the most outstanding questions in reptile evolution; we think we now have an answer," said Sterling Nesbitt, who is an associate professor of geosciences and an affiliated faculty member of the Fralin Life Sciences Institute and the Global Change Center.

Their findings were published in Nature.

Fossils of Dromomeron gregorii, a species of lagerpetid, were first collected in Texas in the 1930s and 1940s, but they weren't properly identified until 2009. Unique to this excavation was a well-preserved partial skull and braincase, which, after further investigation, revealed that these reptiles had a good sense of equilibrium and were likely agile animals.

After finding more lagerpetid species in South America, paleontologists were able to create a pretty good picture of what the lagerpetids were; which were small, wingless reptiles that lived across Pangea during much of the Triassic Period, from 237 to 210 million years ago.

And in the past 15 years, five research groups from six different countries and three continents have come together to right some wrongs in the evolutionary history of the pterosaur, after the recent discovery of many lagerpetid skulls, forelimbs, and vertebrae from the United States, Brazil, Argentina, and Madagascar.

You may be asking yourself, what gave paleontologists the idea to take a closer look at lagerpetids as the closest relatives of pterosaurs? Well, paleontologists have been studying the bones of lagerpetids for quite some time, and they have noted that the length and shape of their bones were similar to the bones of pterosaurs and dinosaurs. But with the few fossils that they had before, it could only be assumed that lagerpetids were a bit closer to dinosaurs.

What really caused a shift in the family tree can be attributed to the recently collected lagerpetid skulls and forelimbs, which displayed features that were more similar to pterosaurs than dinosaurs. And with the help of new technological advances, researchers found that pterosaurs and lagerpetids share far more similarities than meet the eye.

Using micro-computed tomographic (?CT) scanning to reconstruct their brains and sensory systems within the recently discovered skulls, paleontologists determined that the brains and sensory systems of lagerpetids had many similarities with those of pterosaurs.

"CT data has been revolutionary for paleontology," said Stocker, who is an assistant professor of vertebrate paleontology and an affiliated faculty member of the Fralin Life Sciences Institute and the Global Change Center.

"Some of these delicate fossils were collected nearly 80 years ago, and rather than destructively cutting into this first known skull of Dromomeron, we were able to use this technology to carefully reconstruct the brain and inner ear anatomy of these small fossils to help determine the early relatives of pterosaurs."

One stark and mystifying finding was that the flightless lagerpetids had already evolved some of the neuroanatomical features that allowed the pterosaurs to fly, which brought forth even more information on the origin of flight.

"This study is a result of an international effort applying both traditional and cutting-edge techniques," said Martín D. Ezcurra, lead author of the study from the Museo Argentino de Ciencias Naturales in Buenos Aires, Argentina. "This is an example of how modern science and collaboration can shed light on long-standing questions that haunted paleontologists during more than a century."

Ultimately, the study will help bridge the anatomical and evolutionary gaps that exist between pterosaurs and other reptiles. The new evolutionary relationships that have emerged from this study will create a new paradigm, providing a completely new framework for the study of the origin of these reptiles and their flight capabilities.

With the little information that paleontologists had about early pterosaurs, they had often attributed extremely fast evolution for the acquisition of their unique body plan. But now that lagerpetids are deemed the precursors of pterosaurs, paleontologists can say that pterosaurs evolved at the same rate as other major reptile groups, thanks to the newly discovered "middle man."

"Flight is such a fascinating behaviour, and it evolved multiple times during Earth's history," said Serjoscha W. Evers, of the University of Fribourg. "Proposing a new hypothesis of their relationships with other extinct animals is a major step forward in understanding the origins of pterosaur flight."

Some questions still remain in this evolutionary mystery. Now that lagerpetids are the closest relatives of pterosaurs, why are they still lacking some of the key characteristics of pterosaurs, including the most outstanding of those -- wings?

"We are still missing lots of information about the earliest pterosaurs, and we still don't know how their skeletons transformed into an animal that was capable of flight," said Nesbitt.

Nesbitt, Stocker, and a team of Virginia Tech graduate and undergraduate students will continue to study animals that appeared in the Triassic Period -- a period of time in Earth history when many familiar groups of vertebrates, such as dinosaurs, turtles, mammal relatives, and amphibians, first appeared. If and when conditions are safe, they plan on going into the field to collect more fossils from the Triassic Period.

Read more at Science Daily

Image-based navigation could help spacecraft safely land on the moon

 In order for future lunar exploration missions to be successful and land more precisely, engineers must equip spacecraft with technologies that allow them to "see" where they are and travel to where they need to be. Finding specific locations amid the moon's complicated topography is not a simple task.

In research recently published in the AIAA Journal of Spacecraft and Rockets, a multidisciplinary team of engineers demonstrated how a series of lunar images can be used to infer the direction that a spacecraft is moving. This technique, sometimes called visual odometry, allows navigation information to be gathered even when a good map isn't available. The goal is to allow spacecraft to more accurately target and land at a specific location on the moon without requiring a complete map of its surface.

"The issue is really precision landing," said John Christian, an associate professor of aerospace engineering at Rensselaer Polytechnic Institute and first author on the paper. "There's been a big drive to make the landing footprint smaller so we can go closer to places of either scientific interest or interest for future human exploration."

In this research, Christian was joined by researchers from Utah State University and Intuitive Machines, LLC (IM) in Houston, Texas. NASA has awarded IM multiple task orders under the agency's Commercial Lunar Payload Services (CLPS) initiative. IM's inaugural IM-1 mission will deliver six CLPS payloads and six commercial payloads to Oceanus Procellarum in the fourth quarter of 2021. Their IM-2 commercial mission will deliver a NASA drill and other payloads to the lunar south pole in the fourth quarter of 2022.

"The interdisciplinary industry/academia team follows in the footsteps of the NASA Autonomous Hazard Avoidance and Landing Technology (ALHAT) project which was a groundbreaking multi-center NASA/industry/academia effort for precision landing," said Timothy Crain, the Vice President of Research and Development at IM. "Using the ALHAT paradigm and technologies as a starting point, we identified a map-free visual odometry technology as being a game-changer for safe and affordable precision landing."

In this paper, the researchers demonstrated how, with a sequence of images, they can determine the direction a spacecraft is moving. Those direction-of-motion measurements, combined with data from other spacecraft sensors and information that scientists already know about the moon's orientation, can be substituted into a series of mathematical relationships to help the spacecraft navigate.

Read more at Science Daily

Southern Hemisphere westerly winds likely to intensify as climate warms

 Polar climate scientists have created the most high resolution past record of the Southern Hemisphere westerly winds. The results, published this week (9 December) in the journal Communications Earth and Environment, describe how the winds are likely to intensify and migrate poleward as the climate warms. The study highlights the urgent need for better models to predict the future.

The westerly winds (known by latitude as the roaring forties, furious fifties, and screaming sixties) are particularly strong due to the absence of continental landmasses in the Southern Ocean to slow them down. They play an important role in regulating how much carbon dioxide (greenhouse gas) is exchanged between the atmosphere and ocean and have been linked to droughts and wildfires, as well as changes in sea ice extent, ocean circulation and ice shelf stability.

Researchers have recreated a 700-year record of the winds using radiocarbon dated sediment cores collected from a coastal lake on sub-Antarctic Marion Island. The island, located southeast of South Africa, is uniquely positioned in the core belt of the winds. The team measured changes in the accumulation rate of wind-blown sea salts by studying diatoms -- tiny algae, specifically microalgae -- embedded in the sediment, together with wind-blown dust, to track past wind strength.

Results show that during cool periods, such as the Little Ice Age (c. 1400-1870 CE), the winds weakened and shifted towards the equator, and during warm periods (before 1450 and after 1920) they intensified and migrated poleward.

Lead author, Dr Bianca Perren, a paleoclimatologist at British Antarctic Survey says:

"From this unique high resolution record we can see how much the westerly winds have changed over the last 700 years. By looking at the past we can better understand what's happening now and what might happen in the future. It's clear that since the 1920s the winds have been migrating south and, with predictions for climate warming, this is likely to continue."

Read more at Science Daily

Database for studying individual differences in language skills

 Although most people learn to speak their mother tongue fluently, native speakers differ in their ability to use language. Adult language users not only differ in the number of words they know, they also differ in how quickly they produce and understand words and sentences. How do individuals differ across language tasks? Are individual differences in language ability related to general cognitive abilities?

Such questions can only be answered by testing large numbers of individuals on a large number of language and cognitive tests. Lead author Florian Hintz and his team designed such a test battery, with the aim of using it in a larger study. In the larger 'IndividuLa' study (funded by the Language in Interaction consortium), the team will be combining test performance data with DNA from a thousand participants. In addition, the brains of about 300 of the 1000 participants will be scanned. However, the authors first needed to pilot the test battery with a smaller number of participants.

"Previous individual-differences studies have often focused on a limited set of skills," says Hintz. "The present dataset goes one step further and provides a comprehensive overview of language users' linguistic and non-linguistic skills, with multiple tests per skill."

The researchers invited 112 participants with ages ranging from 18 to 29 and mixed educational backgrounds to the lab in Nijmegen. Participants completed the battery of 33 tests twice, to establish the reliability of the new measurements, with one month in between test sessions. Testing took about eight hours per participant.

The battery included three types of tests: tests of linguistic experience such as vocabulary size, tests of general cognitive skills such as processing speed or working memory capacity, and tests of linguistic processing skills, measuring production and comprehension of words and sentences. Apart from well-known standardised tests (such as Raven's matrices), the battery included newly developed tests (such as a test on idiomatic expressions and a test on normative rules of Dutch grammar).

The majority of the tests proved to be reliable and suitable for the IndividuLa main study, which is currently ongoing. The team is still recruiting participants for the main study, so native Dutch speakers (between 18 and 30) are invited to take part.

The authors decided to share the data from their pilot study, which is freely available at the UK Data Service data archive (UKDA). The team encourages other researchers to use the database for new analyses. "Individual-differences studies are rarely conducted, as these studies are time-consuming and expensive," says Hintz. "Especially in the current situation, where in-person testing isn't always possible, this resource may provide alternative routes for conducting research."

Read more at Science Daily

Evolution may be to blame for high risk of advanced cancers in humans

 Compared to chimpanzees, our closest evolutionary cousins, humans are particularly prone to developing advanced carcinomas -- the type of tumors that include prostate, breast, lung and colorectal cancers -- even in the absence of known risk factors, such as genetic predisposition or tobacco use.

A recent study led by researchers at University of California San Diego School of Medicine and Moores Cancer Center helps explain why. The study, published December 9, 2020 in FASEB BioAdvances, suggests that an evolutionary genetic mutation unique to humans may be at least partly to blame.

"At some point during human evolution, the SIGLEC12 gene -- and more specifically, the Siglec-12 protein it produces as part of the immune system -- suffered a mutation that eliminated its ability to distinguish between 'self' and invading microbes, so the body needed to get rid of it," said senior author Ajit Varki, MD, Distinguished Professor at UC San Diego School of Medicine and Moores Cancer Center. "But it's not completely gone from the population -- it appears that this dysfunctional form of the Siglec-12 protein went rogue and has now become a liability for the minority of people who still produce it."

Ajit Varki, who is also co-director of both the Glycobiology Research and Training Center and Center for Academic Research and Training in Anthropogeny, led the study with Nissi Varki, MD, professor of pathology at UC San Diego School of Medicine.

In a study of normal and cancerous tissue samples, the researchers discovered that the approximately 30 percent of people who still produce Siglec-12 proteins are at more than twice the risk of developing an advanced cancer during their lifetimes, compared to people who cannot produce Siglec-12.

Normally, genes that encode such dysfunctional proteins are eliminated by the body over time, and approximately two-thirds of the global human population has stopped producing the Siglec-12 protein. Where the gene still hangs around in humans, it was long thought be of no functional relevance, and there have been very few follow-up studies over the two decades since it was discovered. Meanwhile, chimpanzees still produce functioning Siglec-12.

When Nissi Varki's team set out to detect the Siglec-12 in non-cancerous tissue samples using an antibody against the protein, approximately 30 percent of the samples were positive, as expected from the genetic information. In contrast, the majority of advanced cancer samples from the same populations were positive for the Siglec-12 protein.

Looking at a different population of patients with advanced stage colorectal cancer, the researchers found that more than 80 percent had the functional form of the SIGLEC-12 gene, and those patients had a worse outcome than the minority of patients without it.

"These results suggest that the minority of individuals who can still make the protein are at much greater risk of having an advanced cancer," Nissi Varki said.

The researchers also validated their findings in mice by introducing tumor cells engineered to produce Siglec-12. The resulting cancers grew much faster, and turned on many biological pathways known to be involved in advanced cancers, compared to control tumor cells without functioning Siglec-12.

Read more at Science Daily

New geological findings from eastern Fennoscandia add new dimensions to the history of European ice

 In Finland, the majority of the glacial and warm interval records have been interpreted to represent only the last, Weichselian, glacial cycle that took place 11,700-119,000 years ago. Finnish researchers have now revised the crucial part of the existing stratigraphic documentation in southern Finland. The new findings show that a considerable part of the warm interval records extends further back in time than earlier thought. The new results change the established conceptions about glacial history in the area.

The new study conducted at the University of Turku has examined geological stratigraphic sequences in southern and central Finland. The material collected during the study was compared with corresponding stratigraphic sequences in Fennoscandia, the Baltic countries and Europe.

- One of the studied warm interval records may be circa 300,000-400,000 years old. The forests in South Finland were then composed of scots pine and Norway spruce and contained larch, fir and possibly some species related to present-day Strobus pine, says Professor of Geology Matti E. Räsänen.

A major part of the revised warm interval records is, however, attributed to the Röpersdorf-Schöningen interglacial circa 200,000 years ago. The study led by Räsänen has, for the first time, managed to reconstruct the paleogeography, vegetation and climate of this regional interglacial in Fennoscandia. During this interglacial period, the ocean levels were nearly 20m lower than today, and the Gulf of Bothnia hosted fresh water lakes surrounded by boreal pine forests.

- This is why Finland had a continental climate with warmer summers and colder winters than today. The forests were dominated by scots pine and the Siberian spruce was growing even in southern Finland. Several species that nowadays grow on the East European Plain and in Southeast Europe were growing in southern Finland, explains Räsänen.

During the Eemian interglacial 119,000-131,000 years ago, ocean levels were four to six metres higher than today and the Baltic basin was well connected to oceans.

- The dinoflagellate, silicoflagellate and diatom microfossils discovered from the stratigraphic sequences show detailed evidence of the widespread intermixing of continental fresh and marine waters within the shallow Eemian sea coastal waters.

Beginning of the Last Ice Age Cooler than Thought

Most importantly, the research results change the established conceptions about the nature of the temperate Brörup interval in the beginning of the last Weichselian glacial cycle circa 100,000 years ago. The findings from Björkö Island in the UNESCO World Heritage Site of Kvarken Archipelago suggest that during this interval, central and southern Finland supported open birch forest tundra, which was later invaded by spruce, but not boreal pine forests as earlier thought.

Read more at Science Daily

Pupils can learn more effectively through stories than activities

 Storytelling -- the oldest form of teaching -- is the most effective way of teaching primary school children about evolution, say researchers at the Milner Centre for Evolution at the University of Bath.

A randomised controlled trial found that children learn about evolution more effectively when engaged through stories read by the teacher, than through doing tasks to demonstrate the same concept.

The scientists investigated several different methods of teaching evolution in primary schools, to test whether a pupil-centred approach (where pupils took part in an activity) or a teacher-centred approach (where pupils were read a story by the teacher), led to a greater improvement in understanding of the topic.

They also looked at whether using human-based examples of evolution (comparing arm bones in humans with those in animals), or more abstract examples that were harder to emotionally engage with (comparing the patterns of trilobites), produced better results in terms of the children's understanding of evolution.

Whilst all the methods improved the pupils' understanding of evolution, the study, published in the journal Science of Learning, found that the story-based approach combined with the abstract examples of evolution were the most effective lessons.

This goes against educational orthodoxy that states that a pupil-centred approach to learning, using human-based examples with which children can easily identify, should yield the best results.

The study recruited 2500 primary school students who were tested for understanding of evolutionary concepts before and after the lessons.

Professor Laurence Hurst, Director of the Milner Centre for Evolution at the University of Bath, led the study.

He said: "We were really surprised by the results -- we expected that pupils would be more engaged with an activity rather than listening to a story, and that children would identify more strongly with the human-based examples of evolution than the somewhat abstract example of trilobites, but in fact the opposite was true.

"This is the first large randomised controlled trial that is evaluating the effectiveness of different methods of teaching, using similar scientific methods to those used in drug interaction trials to test whether a new treatment works.

"Our results show that we should be careful about our preconceptions of what works best.

"We only tested the teaching of evolution in this way -- it would be interesting to see if these findings also applied to other subjects of the curriculum."

Professor Momna Hejmadi, Associate Dean of the University's Faculty of Science, helped to design the study and co-authored the paper. She said: "Evolution was introduced to the national curriculum for primary schools in 2014.

"It's a really important subject as it forms the foundation for many parts of biology. However, many primary school teachers, if they don't have a science background, are less confident about teaching it.

"At the Milner Centre for Evolution, we've developed a range of free lesson plans using really cheap teaching materials, as well as a free online course for teachers to help them engage their pupils with this important subject.

Read more at Science Daily