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Ant genomes rewrite history of the Panama land bridge

Ant genomes rewrite history of the Panama land bridge | Amazing Science | Scoop.it

Colliding tectonic plates pushed up a strip of land from the watery abyss that once divided North and South America, forming the isthmus of Panama. But a study now hints that this happened millions of years earlier than scientists had thought. Evolutionary and population-genetics data from Eciton army ants, which can only travel on dry ground, suggest that the isthmus formed 4–8 million years ago. The research, published on 25 October in Molecular Ecology1, challenges the long-held idea that the link between continents emerged no more than 3 million years ago.

 

“Our genomic data is very strong evidence that the army ants crossed this region much earlier in time than the model of the simple closure of the isthmus suggests,” says Corrie Moreau, associate curator at the Field Museum in Chicago, Illinois, and co-author of the study. She notes that recent geological studies have also hinted that the isthmus may have emerged earlier than 3 million years ago.


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Elephant history rewritten by ancient genomes after genome sequencing

Elephant history rewritten by ancient genomes after genome sequencing | Amazing Science | Scoop.it
DNA from extinct species forces rethink of elephants’ family tree.

 

Modern elephants are classified into three species: the Asian elephant (Elephas maximus) and two African elephants — the forest-dwellers (Loxodonta cyclotis) and those that live in the savannah (Loxodonta africana). The division of the African elephants, originally considered a single species, was confirmed only in 2010.

 

Scientists had assumed from fossil evidence that an ancient predecessor called the straight-tusked elephant (Paleoloxodon antiquus), which lived in European forests until around 100,000 years ago, was a close relative of Asian elephants.

 

In fact, this ancient species is most closely related to African forest elephants, a genetic analysis now reveals. Even more surprising, living forest elephants in the Congo Basin are closer kin to the extinct species than they are to today’s African savannah-dwellers. And, together with newly announced genomes from ancient mammoths, the analysis also reveals that many different elephant and mammoth species interbred in the past.

 

“It’s mind blowing,” says Tom Gilbert, an evolutionary geneticist at the Natural History Museum of Denmark in Copenhagen. The straight-tusked elephant is little-known even among experts, he says. “And the first thing we hear about it is: here’s the genome.”

 

Love Dalén, a palaeogeneticist at the Swedish Museum of Natural History in Stockholm, says that the study will force a reshuffle of the elephant family tree. “Basically Loxodonta is not valid as a genus name,” he says. He thinks that taxonomists may need to come up with new names for the different species, to better represent the relationship between savannah, forest and straight-tusked elephants.

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Sea ice strongly linked to climate change in past 90 000 years

Sea ice strongly linked to climate change in past 90 000 years | Amazing Science | Scoop.it

“The Arctic sea ice responded very rapidly to past climate changes. During the coldest periods of the past 90,000 years the sea ice edge spread relatively quickly to the Greenland-Scotland Ridge, and probably far into the Atlantic Ocean.” says Ulrike Hoff, a researcher at Centre for Arctic Gas Hydrate, Environment and Climate (CAGE).

 

Sea ice amplifies the climate changes that are occurring at any given time. Its growth and melting has profound effects on climate, the marine environment and ocean circulation.

 

Hoff and colleagues studied the past distribution of sea ice, in the so far longest existing sea ice record in a marine sediment core. The core was retrieved from 1200m water depth from the ocean floor of the Nordic Seas, just off the Faroe Islands. The core represents 90,000 years of sediment layers, and it is by studying those layers that scientist can reveal the changes in sea ice and past climate.

 

It was the tiniest of evidence in these layers that brought this strong confirmation of sea ice behavior to light. They are a type of phytoplankton, called diatoms, and they are everywhere around you. Diatoms are single celled algae with a cell wall made up of silica.

 

“They are the golden brown coating in the glass of a street lamp, and shiny stuff in your make-up. They are even used in tooth paste as a cleaning agent.,” says Hoff. “Diatoms are truly amazing, and can be preserved in marine and lake sediments for millions of years. I have personally examined diatom fossils that are 65 million of years old, and they look much the same as the diatoms that we find living today.”

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History of road-tripping shaped dromedar's DNA

History of road-tripping shaped dromedar's DNA | Amazing Science | Scoop.it
Centuries of caravan domestication and travel left some metaphorical tire marks on Arabian camel genes, researchers find.

 

Arabian camels (Camelus dromedarius) have trekked across ancient caravan routes in Asia and Africa for 3,000 years. But it’s unclear how camels’ domestication has affected their genetic blueprints.

 

To find out, Faisal Almathen of King Faisal University in Saudi Arabia and his colleagues combed through the DNA of 1,083 modern camels and ancient remains of wild and domesticated camels found at archaeological sites going back to 5000 B.C.

 

Camels run high on genetic diversity thanks to periodic restocking from now-extinct wild populations in the centuries after their domestication, the team reports May 9 in the Proceedings of the National Academy of Sciences. Travel on human caravan routes also created a steady flow of genes between different domesticated populations, except in a geographically isolated group in East Africa. That diversity may give some camel populations a leg up in adapting to future changes in climate, the authors suggest. 

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Scientists Want To Sequence The Genome Of Leonardo Da Vinci

Scientists Want To Sequence The Genome Of Leonardo Da Vinci | Amazing Science | Scoop.it

Five hundred years ago, Leonardo da Vinci was pioneering pretty much every field of study going, from poetry to mathematics, engineering, anatomy, science, astronomy, and geology. He wasn’t bad at painting either, apparently. Seemingly inspired by his feverishly creative spirit, scientists have hatched a mad plan to sequence his genome and attempt to piece together his incredible life.

 

The Leonardo Project is bringing together a wealth of scientists, historians, archeologists and art experts from universities around the world. They have recently outlined a few of their plans in a special edition of the Human Evolution journal.

 

The team is going to look for traces of DNA and fingerprints on his books, notepads, paintings, and equipment. They then hope to pair this with information from the hair, bones, fingerprints, and skin cells of his known past and present relatives. As you can imagine, this is no small feat. Much of the work will include tracking the history and final resting place of Leonardo’s family from the 14th century right up to now.

 

Rhonda Roby, a geneticist on the project, spoke to Gizmodo about some of the challenges in finding the physical remnants of Da Vinci, saying: “More and more techniques are being developed to recover DNA from people touching things.” “I also think there’s a possibility of biological material inside paintings,” she added. “The challenge would be actually getting that material out without damaging the artwork.”

 

The legacy of Da VInci’s work in science, engineering, and culture is nothing short of superhuman. But despite this, very little is known about the man himself. One of the things that will be revealed from this genome sequencing is the appearance of the Renaissance polymath. By fitting together bits of the genetic jigsaw, they’ll be able to get a fair idea of his eye color, skin tone, hair color, weight, height, and face shape. They also reckon they’ll be able to get a fair idea of his diet, his health, and his personality.

 

There’re no plans to clone the great polymath just yet, though.

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Ancient DNA shows European wipe-out of early Americans

Ancient DNA shows European wipe-out of early Americans | Amazing Science | Scoop.it

The first large-scale study of ancient DNA from early American people has confirmed the devastating impact of European colonisation on the Indigenous American populations of the time.

Led by the University of Adelaide's Australian Centre for Ancient DNA (ACAD), the researchers have reconstructed a genetic history of Indigenous American populations by looking directly into the DNA of 92 pre-Columbian mummies and skeletons, between 500 and 8600 years old.

 

Published today in Science Advances, the study reveals a striking absence of the pre-Columbian genetic lineages in modern Indigenous Americans; showing extinction of these lineages with the arrival of the Spaniards.

 

"Surprisingly, none of the genetic lineages we found in almost 100 ancient humans were present, or showed evidence of descendants, in today's Indigenous populations," says joint lead author Dr Bastien Llamas, Senior Research Associate with ACAD. "This separation appears to have been established as early as 9000 years ago and was completely unexpected, so we examined many demographic scenarios to try and explain the pattern."

 

"The only scenario that fit our observations was that shortly after the initial colonisation, populations were established that subsequently stayed geographically isolated from one another, and that a major portion of these populations later became extinct following European contact. This closely matches the historical reports of a major demographic collapse immediately after the Spaniards arrived in the late 1400s."

 

The research team, which also includes members from the University of California at Santa Cruz (UCSC) and Harvard Medical School, studied maternal genetic lineages by sequencing whole mitochondrial genomes extracted from bone and teeth samples from 92 pre-Columbian--mainly South American--human mummies and skeletons.

 

The ancient genetic signals also provide a more precise timing of the first people entering the Americas--via the Beringian land bridge that connected Asia and the north-western tip of North America during the last Ice Age.

 

"Our genetic reconstruction confirms that the first Americans entered around 16,000 years ago via the Pacific coast, skirting around the massive ice sheets that blocked an inland corridor route which only opened much later," says Professor Alan Cooper, Director of ACAD. "They spread southward remarkably swiftly, reaching southern Chile by 14,600 years ago."

 

"Genetic diversity in these early people from Asia was limited by the small founding populations which were isolated on the Beringian land bridge for around 2400 to 9000 years," says joint lead author Dr Lars Fehren-Schmitz, from UCSC. "It was at the peak of the last Ice Age, when cold deserts and ice sheets blocked human movement, and limited resources would have constrained population size. This long isolation of a small group of people brewed the unique genetic diversity observed in the early Americans."

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Earth had oxygen 800 million years earlier than thought

Earth had oxygen 800 million years earlier than thought | Amazing Science | Scoop.it

Until recently, scientists thought that oxygen first became a part of our atmosphere 2.2 billion years ago. But a new study pushes this further back in time, to about 3.8 billion years ago.

 

"I was quite shocked when I first saw the results,” says lead-author Robert Frei, who works at the Department of Earth Science and Nature Management at the University of Copenhagen, Denmark.

 

“This strikes into a very sensitive part of science, in which there is relatively little evidence, and yet the entire scientific community don’t believe that there was oxygen at this time. I’ve struggled against many critical peers and it’s taken me over a year to get the article published,” says Frei, adding that he feels confident about the results.

 

The conclusions are important and should improve our understanding of Earth’s history, says postdoc Emma Hammarlund from The University of Southern Denmark, who was not involved in the new study.

 

“The picture is not made any simpler perhaps, but the truth is rarely black and white. It’s a carefully executed study and argument,” she says.

 

The new results are published in the journal Scientific Reports.


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Globally unique double crater identified in Sweden: Impact 460 million years ago

Globally unique double crater identified in Sweden: Impact 460 million years ago | Amazing Science | Scoop.it

Researchers at the University of Gothenburg have found traces of two enormous meteorite impacts in the Swedish county of Jämtland, a twin strike that occurred around 460 million years ago.

The researchers have discovered two craters in Jämtland. One is enormous, while the other is a tenth of the size of the first. "The two meteorite impacts occurred at the same time, 458 million years ago, and formed these two craters," says Erik Sturkell, Professor of Geophysics at the University of Gothenburg.

Erik Sturkell and his research colleagues found one of the craters 20 kilometres south of Östersund in Brunsflo. This is an enormous crater, with a diameter of 7.5 kilometers. The smaller crater is located 16 kilometers from there, and has a diameter of 700 meters.


The two meteorite impacts 458 million years ago were not the only ones to strike Earth at this time. "Around 470 million years ago, two large asteroids collided in the asteroid belt between Mars and Jupiter, and many fragments were thrown off in new orbits. Many of these crashed on Earth, such as these two in Jämtland," says Erik Sturkell.


Jämtland was under the sea at the time, with a water depth of 500 meters at the points where two meteorites simultaneously stuck. Double impacts like this are very unusual. This is the first double impact on Earth that has been conclusively proved. "Information from drilling operations demonstrates that identical sequences are present in the two craters, and the sediment above the impact sequences is of the same age. In other words, these are simultaneous impacts," says Erik Sturkell. The water was forced away during the impact, and for a hundred seconds these enormous pits were completely dry.


"The water then rushed back in, bringing with it fragments from the meteorites mixed with material that had been ejected during the explosion and with the gigantic wave that tore away parts of the sea bed," says Erik Sturkell.

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Ancient Death Toll of Pacific Island Birds Confirmed in New Study

Ancient Death Toll of Pacific Island Birds Confirmed in New Study | Amazing Science | Scoop.it
The first Polynesian settlers caused nearly 1,000 flightless birds like the dodo to go extinct, new research suggests


Almost 4,000 years ago, tropical Pacific Islands were an untouched paradise, but the arrival of the first people in places like Hawaii and Fiji caused irreversible damage to these natural havens, due to overhunting and deforestation. As a result, birds disappeared. But understanding the scale and extent of these extinctions has been hampered by uncertainties in the fossil record.


Professor Tim Blackburn, Director of ZSL's Institute of Zoology says: "We studied fossils from 41 tropical Pacific islands and using new techniques we were able to gauge how many extra species of bird disappeared without leaving any trace." They found that 160 species of non-passerine land birds (non-perching birds which generally have feet designed for specific functions, for example webbed for swimming) went extinct without a trace after the first humans arrived on these islands alone. "If we take into account all the other islands in the tropical Pacific, as well as seabirds and songbirds, the total extinction toll is likely to have been around 1,300 bird species," Professor Blackburn added.


Species lost include several species of moa-nalos, large flightless waterfowl from Hawai'i, and the New Caledonian Sylviornis, a relative of the game birds (pheasants, grouse, etc) but which weighed in at around 30kg, three times as heavy as a swan. Certain islands and bird species were particularly vulnerable to hunting and habitat destruction. Small, dry islands lost more species because they were more easily deforested and had fewer places for birds to hide from hunters. Flightless birds were over 30 times more likely to become extinct that those that could fly.


Bird extinctions in the tropical Pacific did not stop with these losses. Forty more species disappeared after Europeans arrived, and many more species are still threatened with extinction today.

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Oldest fossils turn out to be peculiarly shaped minerals

Oldest fossils turn out to be peculiarly shaped minerals | Amazing Science | Scoop.it

New analysis of world-famous 3.46 billion-year-old rocks by researchers from the University of Bristol, the University of Oxford and UWA (the University of Western Australia) is set to finally resolve a long running evolutionary controversy.


The new research, published this week in Proceedings of the National Academy of Sciences, shows that structures once thought to be Earth's oldest microfossils do not compare with younger fossil candidates but have, instead, the character of peculiarly shaped minerals.


In 1993, US scientist Bill Schopf described tiny carbon-rich filaments within the 3.46 billion-year-old Apex chert (fine-grained sedimentary rock) from the Pilbara region of Western Australia, which he likened to certain forms of bacteria, including cyanobacteria. These 'Apex chert microfossils' -- between 0.5 and 20 micrometres wide -- soon became enshrined in textbooks, museum displays, popular science books and online reference guides as the earliest evidence for life on Earth. In 1996, these structures were even used to test and help refute the case against 'microfossils' in the Martian meteorite ALH 84001.


Even so, their curious color and complexity gave rise to some early questions. Gravest doubts emerged in 2002, when a team led by Oxford's Professor Martin Brasier (co-author of this current study) revealed that the host rock was not part of a simple sedimentary unit but rather came from a complex, high-temperature hydrothermal vein, with evidence for multiple episodes of subsurface fluid flow over a long time. His team advanced an alternative hypothesis, stating that these curious structures were not true microfossils but pseudofossils formed by the redistribution of carbon around mineral grains during these hydrothermal events.


Although other research teams have since supported the hydrothermal context of Professor Brasier, the 'Apex microfossil' debate has remained hard to resolve because scientific instrumentation has only recently reached the level of resolution needed to map both chemical composition and morphology of these 'microfossils' at the sub-micrometre scale.


Now Dr David Wacey, a Marie Curie Fellow in Bristol's School of Earth Sciences, in collaboration with the late Professor Brasier, has come up with new high-spatial resolution data that clearly demonstrate that the 'Apex chert microfossils' comprise stacks of plate-like clay minerals arranged into branched and tapered worm-like chains. Carbon was then absorbed onto the edges of these minerals during the circulation of hydrothermal fluids, giving a false impression of carbon-rich cell-like walls.


Dr Wacey and team used transmission electron microscopy to examine ultrathin slices of 'microfossil' candidates, to build up nanoscale maps of their size, shape, mineral chemistry and distribution of carbon. Dr Wacey explains: "It soon became clear that the distribution of carbon was unlike anything seen in authentic microfossils. A false appearance of cellular compartments is given by multiple plates of clay minerals having a chemistry entirely compatible with a high temperature hydrothermal setting.

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Got milk? Humans did 5,000 years ago

Got milk? Humans did 5,000 years ago | Amazing Science | Scoop.it

Why do humans drink milk? Archaeologists and geneticists have been puzzling over this question since they discovered that the mutations allowing adults to drink milk are under the strongest selection of any in the human genome. These mutations cause the human body to produce the intestinal enzyme lactase, which digests lactose milk sugar during infancy, long after weaning. This lactase persistence is prevalent only in some populations around the world, such as in Northern Europe.


In most other people of the world, the lactose cannot be properly digested and can cause diarrhea or other symptoms of lactose intolerance resulting from the gases produced by fermentation by the gut bacteria. Some dairy products, such as yogurt and cheese, have had their lactose content reduced or removed through processing. In the case of cheese, the lactose ends up in the whey, where it is often fed to pigs and other animals. If it is so easy to remove milk sugars, and the mutation is only required for drinking raw milk or whey, why is it under such strong selection?


An international team of researchers has shed new light on this puzzling question through an unusual source: calcified dental plaque on ancient human teeth. Now a breakthrough by the international team, reported in the journal Scientific Reports, provides the first direct evidence of milk drinking from human dental calculus, a mineralized form of dental plaque. Using the latest mass spectrometry-based techniques, the team detected a milk protein, beta-lactoglobulin (which they had previously reported from a modern dental plaque sample), in ancient remains.


“It seemed too good to be true; beta-lactoglobulin is the dominant whey protein—the one used by bodybuilders to build muscle mass—and therefore the ideal marker for milk consumption,” says Jessica Hendy from the University of York’s BioArCh research facility and the study’s co-lead author. The new research provides direct protein evidence that cattle, sheep, and goat whey has been consumed by human populations for at least 5,000 years. This corroborates previous isotopic evidence for milk fats identified on pottery and cooking utensils in early farming communities.


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Saberes Sin Fronteras OVS's curator insight, November 30, 2014 5:27 PM

Sólo los pueblos de Europa norte tienen la enzima necesaria para procesar la lactosa, la mayoría de la humanidad no, Por eso la ganadería del vacuno es no sólo un problema ecológico, por producir demasiado dióxido de carbono, sino tambien un problema sanitario.

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The Sound So Loud That It Circled the Earth Four Times

The Sound So Loud That It Circled the Earth Four Times | Amazing Science | Scoop.it

On 27 August 1883, the Earth let out a noise louder than any it has made since.


It was 10:02 AM local time when the sound emerged from the island of Krakatoa, which sits between Java and Sumatra in Indonesia. It was heard 1,300 miles away in the Andaman and Nicobar islands (“extraordinary sounds were heard, as of guns firing”); 2,000 miles away in New Guinea and Western Australia (“a series of loud reports, resembling those of artillery in a north-westerly direction”); and even 3,000 miles away in the Indian Ocean island of Rodrigues, near Mauritius* (“coming from the eastward, like the distant roar of heavy guns.”1) In all, it was heard by people in over 50 different geographical locations, together spanning an area covering a thirteenth of the globe.


Think, for a moment, just how crazy this is. If you’re in Boston and someone tells you that they heard a sound coming from New York City, you’re probably going to give them a funny look. But Boston is a mere 200 miles from New York. What we’re talking about here is like being in Boston and clearly hearing a noise coming from Dublin, Ireland.


Traveling at the speed of sound (766 miles or 1,233 kilometers per hour), it takes a noise about 4 hours to cover that distance. This is the most distant sound that has ever been heard in recorded history.

So what could possibly create such an earth-shatteringly loud bang? A volcano on Krakatoa had just erupted with a force so great that it tore the island apart, emitting a plume of smoke that reached 17 miles into the atmosphere, according to a geologist who witnessed it1. You could use this observation to calculate that stuff spewed out of the volcano at over 1,600 miles per hour—or nearly half a mile per second. That’s more than twice the speed of sound.


This explosion created a deadly tsunami with waves over a hundred feet (30 meters) in height. One hundred sixty-five coastal villages and settlements were swept away and entirely destroyed. In all, the Dutch (the colonial rulers of Indonesia at the time) estimated the death toll at 36,417, while other estimates exceed 120,000.

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New insights on an ancient plague could improve modern treatments for infections

New insights on an ancient plague could improve modern treatments for infections | Amazing Science | Scoop.it
While bubonic plague would seem a blight of the past, there have been recent outbreaks in India, Madagascar and the Congo. And it's mode of infection now appears similar to that used by other well-adapted human pathogens, such as the HIV virus.


In their study, the Duke and Duke-NUS researchers set out to determine whether the large swellings that are the signature feature of bubonic plague -- the swollen lymph nodes, or buboes at the neck, underarms and groins of infected patients -- result from the pathogen or as an immune response.


It turns out to be both. "The bacteria actually turn the immune cells against the body," said senior author Soman Abraham, Ph.D. a professor of pathology at Duke and professor of emerging infectious diseases at Duke-NUS. "The bacteria enter the draining lymph node and actually hide undetected in immune cells, notably the dendritic cells and monocytes, where they multiply. Meanwhile, the immune cells send signals to bring in even more recruits, causing the lymph nodes to grow massively and providing a safe haven for microbial multiplication."


The bacteria are then able to travel from lymph node to lymph node within the dendritic cells and monocytes, eventually infiltrating the blood and lungs. From there, the infection can spread through body fluids directly to other people, or via biting insects such as fleas.
Abraham, St. John and colleagues note that there are several potential drug candidates that target the trafficking pathways that the bubonic plague bacteria use. In animal models, the researchers successfully used some of these therapies to prevent the bacteria from reaching systemic infection, markedly improving survival and recovery.


"This work demonstrates that it may be possible to target the trafficking of host immune cells and not the pathogens themselves to effectively treat infection and reduce mortality," St. John said. "In view of the growing emergency of multi-resistant bacteria, this strategy could become very attractive."

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Lilia Hernández's curator insight, September 22, 2014 7:06 AM

No lo puedo evitar, la microbiología siempre será mi más grande pasión. Noticias de cazadores de microbios :)

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Researchers restore first ever computer music recording

Researchers restore first ever computer music recording | Amazing Science | Scoop.it
The first recording of computer-generated music, created in 1951 on a gigantic contraption built by British genius Alan Turing, is restored by New Zealand researchers.

 

The two-minute recording features short snippets of the tunes rendered in a slightly grating drone, like electronic bagpipes.

There are also a number of glitches and when the music halts during the Glenn Miller number, a presenter comments: "The machine's obviously not in the mood.

 

While Turing programmed the first musical notes into a computer, he had little interest in stringing them together into tunes. That work was carried out by a school teacher named Christopher Strachey, who went on to become a renowned computer scientist in his own right.

 

Strachey recalled that Turing's taciturn response upon hearing his machine play music was "good show".

 

Turing was a computer scientist, philosopher and cryptologist who played a crucial role in breaking the Nazis' Enigma Code.

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The Anthropocene epoch: scientists declare dawn of human-influenced age

The Anthropocene epoch: scientists declare dawn of human-influenced age | Amazing Science | Scoop.it

Humanity’s impact on the Earth is now so profound that a new geological epoch – the Anthropocene – needs to be declared, according to an official expert group who presented the recommendation to the International Geological Congress in Cape Town on Monday.

 

The new epoch should begin about 1950, the experts said, and was likely to be defined by the radioactive elements dispersed across the planet by nuclear bomb tests, although an array of other signals, including plastic pollution, soot from power stations, concrete, and even the bones left by the global proliferation of the domestic chicken were now under consideration.

 

The current epoch, the Holocene, is the 12,000 years of stable climate since the last ice age during which all human civilisation developed. But the striking acceleration since the mid-20th century of carbon dioxide emissions and sea level rise, the global mass extinction of species, and the transformation of land by deforestation and development mark the end of that slice of geological time, the experts argue.

 

The Earth is so profoundly changed that the Holocene must give way to the Anthropocene. “The significance of the Anthropocene is that it sets a different trajectory for the Earth system, of which we of course are part,” said Prof Jan Zalasiewicz, a geologist at the University of Leicester and chair of the Working Group on the Anthropocene (WGA), which started work in 2009.

 

“If our recommendation is accepted, the Anthropocene will have started just a little before I was born,” he said. “We have lived most of our lives in something called the Anthropocene and are just realising the scale and permanence of the change.”

 

Prof Colin Waters, principal geologist at the British Geological Survey and WGA secretary, said: “Being able to pinpoint an interval of time is saying something about how we have had an incredible impact on the environment of our planet. The concept of the Anthropocene manages to pull all these ideas of environmental change together.”

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Complex life on Earth began a billion years earlier than previously thought, study argues

Complex life on Earth began a billion years earlier than previously thought, study argues | Amazing Science | Scoop.it

A claim by researchers that complex life on Earth may have evolved a billion years earlier than previously thought has immediately divided scientists in the field, with some hailing the evidence as rock-solid and others unconvinced.

The researchers, writing in the journal Nature Communications, said they had uncovered fossils showing that complex life on Earth began more than 1.5bn years ago.

After first emerging from the primordial soup, life remained primitive and single-celled for billions of years, but some of those cells eventually congregated like clones in a colony. Scientists took to calling the later part of this period the “boring billion” because evolution seemed to have stalled.

But at some point there was a leap – arguably second in importance only to the appearance of life itself – towards complex organisms with multiple cells.

This transition progressively gave rise to all the plants and animals that have ever existed.

Exactly when multi-celled “eukaryotes” – organisms in which differentiated cells each contain a membrane-bound nucleus with genetic material – showed up has inflamed scientific passions for many decades.

“Our discovery pushes back nearly one billion years the appearance of macroscopic, multi-cellular eukaryotes compared to previous research,” said Maoyan Zhu, a professor at the Nanjing Institute of Geology and Palaeontology.

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Why are carrots orange? Genome sequencing gives clues

Why are carrots orange? Genome sequencing gives clues | Amazing Science | Scoop.it
The humble supermarket carrot owes its deep orange colour to a newly-found gene, according to an analysis of the full carrot genome.

 

Carrots are members of the Apiaceae family of plants, which include celery, parsley, fennel, coriander, dill and parsnip. They are related to crops in the sunflower, artichoke and lettuce — the latter which it split from about 72 million years ago. Historically, carrots had small white roots with a woody interior. They most likely came from areas of Iran and Afghanistan, where they still grow today.

 

Initially they were grown for their aromatic leaves, but over hundreds of years farmers turned a naturally occurring subspecies of the carrot into a larger, less woody root. Domesticated yellow and purple carrots were found in Central Asia around 1,000 years ago, and an orange version emerged in late 16th century Holland, most probably from crossing yellow carrots with purple ones.

 

By using NGS technologies, researchers sequenced the genomes of 35 different carrot specimens and subspecies, both wild and cultivated, in an attempt to understand how carrots evolved into those we find in our fridge. They found a gene responsible for the high concentration of beta-carotene in the orange carrot taproot. They also identified more than 32,000 genes in a typical orange carrot.

 

The genome could help breed carrots that have high levels of beta-carotene and are pest resistant.

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1917 astronomical plate has first-ever evidence of exoplanetary system

1917 astronomical plate has first-ever evidence of exoplanetary system | Amazing Science | Scoop.it

You can never predict what treasure might be hiding in your own basement. We didn’t know it a year ago, but it turns out that a 1917 image on an astronomical glass plate from our Carnegie Observatories’ collection shows the first-ever evidence of a planetary system beyond our own Sun. This unexpected find was recognized in the process of researching an article about planetary systems surrounding white dwarf stars in New Astronomy Reviews.

 

Here’s what happened: about a year ago, the review’s author, Jay Farihi of University College London, contacted our Observatories’ Director, John Mulchaey. He was looking for a plate in the Carnegie archive that contained a spectrum of van Maanen’s star, a white dwarf discovered by Dutch-American astronomer Adriaan van Maanen in the very year our own plate was made.

 

Stellar spectra are recordings of the light emitted by distant stars. Spectra spread out all of the component colors of light, like a rainbow from a prism, and they can teach astronomers about a star’s chemical composition. They can also tell them how the light emitted by a star is affected by the chemistry of the things it passes through before reaching us on Earth.

 

Stellar spectra images allowed 19th century astronomers to develop a system for classifying stars that is still used today. Modern astronomers use digital tools to image stars, but for decades, they would use glass photographic plates both to take images of the sky, and to record stellar spectra.

 

As requested, the Observatories located the 1917 plate, made by former Observatories Director Walter Adams at Mount Wilson Observatory, which was then part of Carnegie. Other than a notation on the plate’s sleeve indicating that the star looked a bit warmer than our own Sun, everything seemed very ordinary.

However, when Farihi examined the spectrum, he found something quite extraordinary.

 

The clue was in what’s called an “absorption line” on the spectrum. Absorption lines indicate “missing pieces,” areas where the light coming from a star passed through something and had a particular color of light absorbed by that substance. These lines indicate the chemical makeup of the interfering object.

 

Carnegie’s 1917 spectrum of van Maanen’s star revealed the presence of heavier elements, such as calcium, magnesium, and iron, which should have long since disappeared into the star's interior due to their weight.

 

Only within the last 12 years has it become clear to astronomers that van Maanen's star and other white dwarfs with heavy elements in their spectra represent a type of planetary system featuring vast rings of rocky planetary remnants that deposit debris into the stellar atmosphere. These recently discovered systems are called “polluted white dwarfs.” They were a surprise to astronomers, because white dwarfs are stars like our own Sun at the end of their lifetimes, so it was not at all expected that they would have leftover planetary material around them at that stage.

 

“The unexpected realization that this 1917 plate from our archive contains the earliest recorded evidence of a polluted white dwarf system is just incredible,” Mulchaey said. “And the fact that it was made by such a prominent astronomer in our history as Walter Adams enhances the excitement.”

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Study reveals evolution of malaria

Study reveals evolution of malaria | Amazing Science | Scoop.it

Malaria affects close to 500 million people every year, but we're not the only ones—different species of malaria parasite can infect birds, bats, and other mammals too. A Field Museum study published in Molecular Phylogenetics and Evolution reveals a new take on the evolution of different malaria species and contributes to the ongoing search for the origins of malaria in humans."We can't begin to understand how malaria spread to humans until we understand its evolutionary history," explained lead author Holly Lutz, a Ph.D. candidate at Cornell University and a longtime affiliate of The Field Museum. "In learning about its past, we may be better able to understand the effects it has on us."

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If the World Began Again, Would Life as We Know It Exist?

If the World Began Again, Would Life as We Know It Exist? | Amazing Science | Scoop.it

Experiments in evolution are exploring what would happen if we rewound the tape of life.


Via Complexity Digest
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Mortality Gap: Have Women Always Lived Longer than Men?

Mortality Gap: Have Women Always Lived Longer than Men? | Amazing Science | Scoop.it

In every single country on the planet, women live longer than men. In response to this unpleasant fact, men are fond of replying, "That's because we have to put up with women." Humorous though it may be, that's not the actual reason women live longer than men. In fact, it wasn't until the beginning of the 20th Century that the "mortality gap" between men and women became so striking.


To investigate the underlying reason for the gender gap in life expectancy, a team of researchers examined mortality data for people born between 1800 and 1935 in 13 developed countries. Using this data, they were able to determine changes in the male-female mortality ratio, as well as determine when and why women began to outlive men.


In the figure above, each birth cohort is represented by a single colored line. For example, people born between 1800 and 1819 are represented by 20 different lines, each of which is colored black; people born between 1920 and 1935 are represented by 16 colored lines, each of which is colored red. The chart plots age on the X-axis (i.e., "age at time of death") against the male-female mortality rate ratio on the Y-axis.


The figure shows that the relative mortality rate for men gets worse in subsequent years. Compare the mortality rates at age 60, for instance. The mortality rate ratio for people born between 1800 and 1839 (black and gray lines) hovers roughly around 1.2; that means that about 120 men died for every 100 women who died at age 60. Just a few decades later, a dramatic shift occurs: the male-female mortality rate ratio for people born between 1880 and 1899 (green lines) skyrockets to 1.6, meaning that 160 men died for every 100 women who died at age 60. Then it goes from bad to worse. For the 1920-1935 birth cohort, the ratio is a shocking 2.1 at age 60, meaning that 210 men died for every 100 women.


Why is this the case? The authors' analysis suggests two major factors: The first is smoking, which is more common among men. (With smoking factored out, the pattern of an increasing male-female mortality ratio still persists but to a lesser extent, as shown above.) The second is cardiovascular disease, a condition to which men seem to be more vulnerable than women. This may be due to gender differences in diet, lifestyle, and even genetics. Indeed, the researchers found that cardiovascular disease was the major factor causing excess deaths among men as compared to women.

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Cheesy, metallic, sweet: 170-year-old champagne is clue to winemaking’s past

Cheesy, metallic, sweet: 170-year-old champagne is clue to winemaking’s past | Amazing Science | Scoop.it

When Philippe Jeandet sampled what is probably the oldest champagne ever tasted, he was allowed just one droplet squirted from a microsyringe. Divers retrieved 168 bottles of the 170-year-old champagne from the bottom of the Baltic Sea in an unprecedented haul in 2010, but only 2 millilitres of the drink reached Jeandet's laboratory for analysis.


The small sample shows that the seabed preserved the champagne surprisingly well, and offers clues about nineteenth-century winemaking practices, says Jeandet, a biochemist at the University of Reims Champagne-Ardenne in France. He and his colleagues report their findings on 20 April in the Proceedings of the National Academy of Sciences1.


The bottles were discovered in a shipwreck off the Finnish Åland archipelago, and identified as early nineteenth-century by engravings on their corks. In 2011, two were auctioned off, and one was sold for €30,000 (then US$44,000), a record for champagne. The money went to fund scholarships in marine archaeology projects, says Björn Häggblom, a spokesman for the government of Åland. Eleven more bottles were sold in 2012; the others are stored in Åland and may be auctioned later. Five beer bottles were also found in the wreck, and an analysis of the beer was published earlier this year2.

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The Rise and Fall of the World's Nuclear Arsenal Over 70 Years

The Rise and Fall of the World's Nuclear Arsenal Over 70 Years | Amazing Science | Scoop.it

Since 1987, the Bulletin of the Atomic Scientists has been counting up each country's nuclear arsenal in its Nuclear Notebook, peeling back the veil of secrecy that often surrounds these numbers. The Bulletin has now gone and made its Nuclear Notebook into a neat interactive graphic.


There are nine nuclear states: the U.S., Russia, the United Kingdom, France, China, India, Pakistan, Israel, and North Korea. The 70 years worth of data isn't necessarily surprising, but it really drives home how the world's nuclear arsenal is completely dominated by the U.S. and Russia. The other countries barely register as a blip. The full interactive graphic lets you sift through the data country by country and year by year. Check it out at the Bulletin's website.

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Ancient Computer Even More Ancient Than Previously Thought

Ancient Computer Even More Ancient Than Previously Thought | Amazing Science | Scoop.it

The astonishing Antikythera mechanism is even older than previously suspected, new research suggests. Instead of being "1500 years ahead of its time," it may have been closer to 1800.


The mechanism was found in 1901 in the wreck of a ship that sank in the Aegean Sea around 60 BC. Though its origins are unknown, it could be used to calculate astronomical motion, making it a sort of forerunner to computers.


The sheer sophistication of the device makes it mysterious, being more advanced than any known instrument of its day – or for centuries thereafter. Even with parts missing after spending such a long time in the briny deep, it was examined to have at least 30 gears. This is perhaps why for many, it represents the pinnacle of technology of the ancient world and what was lost during the Dark Ages.


If devices such as this had survived, Kepler might have found the task of explaining the orbits of the planets far easier to achieve. Although the makers likely would not have understood why the moon slowed down and sped up in its orbit, they were sufficiently aware of the phenomenon. In fact, the mechanism mimics it precisely. One of the mechanism's functions was to predict eclipses, and a study of these dials indicates it was operating on a calender starting from 205 BC.


Estimates of the mechanism's date of manufacture have gradually been pushed back, starting with the year in which it sank. The device was housed in a box, which has engravings dated to 80 to 90BC, but the lettering appears consistent with a date of 100 to 150 BC


However, in The Archive of History of Exact Sciences, Dr. Christian Carman of Argentina's National University of Quilmes and Dr. James Evans of the University of Puget Sound believe they have identified the solar eclipse that occurs in the 13th month of the mechanism's calender. If so, this would make its start date, when the dials are set to zero, May 205 BC.

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Aids: Origin of HIV pandemic 'was 1920s Kinshasa'

Aids: Origin of HIV pandemic 'was 1920s Kinshasa' | Amazing Science | Scoop.it

The origin of the Aids pandemic has been traced to the 1920s in the city of Kinshasa, in what is now the Democratic Republic of Congo, scientists say.


An international team of scientists say a "perfect storm" of population growth, sex and railways allowed HIV to spread. A feat of viral archaeology was used to find the pandemic's origin, the team report in the journal Science. They used archived samples of HIV's genetic code to trace its source, with evidence pointing to 1920s Kinshasa.


Their report says a roaring sex trade, rapid population growth and unsterilized needles used in health clinics probably spread the virus. Meanwhile Belgium-backed railways had one million people flowing through the city each year, taking the virus to neighboring regions. Experts said it was a fascinating insight into the start of the pandemic. HIV came to global attention in the 1980s and has infected nearly 75 million people.


A team at the University of Oxford and the University of Leuven, in Belgium, tried to reconstruct HIV's "family tree" and find out where its oldest ancestors came from. The research group analyzed mutations in HIV's genetic code. "You can see the footprints of history in today's genomes, it has left a record, a mutation mark in the HIV genome that can't be eradicated," said Prof Oliver Pybus from the University of Oxford.


HIV is a mutated version of a chimpanzee virus, known as simian immunodeficiency virus (SIV), which probably made the species-jump through contact with infected blood while handling bush meat. The virus made the jump on multiple occasions. One event led to HIV-1 subgroup O which affects tens of thousands in Cameroon. Yet only one cross-species jump, HIV-1 subgroup M, went on to infect millions of people across every country in the world.


The answer to why this happened lies in the era of black and white film and the tail-end of the European empires. In the 1920s, Kinshasa (called Leopoldville until 1966) was part of the Belgian Congo. Prof Oliver Pybus said: "It was a very large and very rapidly growing area and colonial medical records show there was a high incidence of various sexually transmitted diseases."

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