Amazing Science
775.3K views | +109 today
Follow
Amazing Science
Amazing science facts - 3D_printing • aging • AI • anthropology • art • astronomy • bigdata • bioinformatics • biology • biotech • chemistry • computers • cosmology • education • environment • evolution • future • genetics • genomics • geosciences • green_energy • history • language • map • material_science • math • med • medicine • microscopy • nanotech • neuroscience • paleontology • photography • photonics • physics • postings • robotics • science • technology • video
Your new post is loading...
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Carbon dioxide release from an acifying ocean ended the last Ice Age, a study suggests

Carbon dioxide release from an acifying ocean ended the last Ice Age, a study suggests | Amazing Science | Scoop.it

Its release into the atmosphere drove the shift towards a warmer period, according to scientists at the University of SouthamptonThe research, published in Nature, is based on analysing chemical signals in the shells of ancient plankton. The world's oceans absorb about a third of the atmospheric carbon dioxide from burning fossil fuels. Scientists predict that as the oceans warm, their ability to absorb atmospheric carbon dioxide will be reduced, potentially leading to faster global warming.


Dr Miguel Martinez-Boti, who co-led the study, said the findings showed that there was a link between very high concentrations of dissolved carbon dioxide in parts of the ocean and rises in atmospheric carbon dioxide at the end of the last Ice Age. "This increases our understanding of the role of the ocean in the carbon cycle," he told BBC News. "The ocean is a much bigger reservoir for carbon than the atmosphere, so how the ocean interacts with the atmosphere is very important."


The research is based on analysis of ancient marine organisms that lived on the surface of the oceans thousands of years ago. The acidity of the seawater they inhabited can be gleaned from the chemical signature left in their shells, which in turn allows the amount of carbon dioxide in the water to be calculated.


Co-researcher, Dr Gavin Foster, said: "Just like the way the oceans have stored around 30% of humanity's fossil fuel emissions over the last 100 years or so, our new data confirms that natural variations in atmospheric carbon dioxide between ice ages and warm interglacials are driven largely by changes in the amount of carbon stored in our oceans."

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Ancient Earth Had Weird Chemistry: During Permian Mass Extinction Soil was Acidic Like Lemon Juice

Ancient Earth Had Weird Chemistry: During Permian Mass Extinction Soil was Acidic Like Lemon Juice | Amazing Science | Scoop.it

During the worst mass extinction in Earth's history, acid rain may have at times made the ground as acidic as lemon juice, new research shows. The mass extinction at the end of the Permian period, about 250 million years ago, was the most extreme die-off in Earth's history. The catastrophe killed as much as 95 percent of ocean species.


The highly level of acidity in the soil at the time of the extinction was revealed in the new study when researchers looked at levels of a compound called vanillin in rocks that date to that time. The chemical is the main ingredient in natural vanilla extract and is also produced when wood decomposes. Normally, bacteria in the soil convert vanillin into vanillic acid, but acidic conditions hinder this process.


The researchers found that the ratios of vanillic acid to vanillin in the rocks show that the level of acidity of the soil at the end of the Permian could have been close to that of vinegar or lemon juice. "We have used methods from the present-day food industry to work out what happened during an end-Permian food-chain collapse," said lead study author Mark Sephton, a geochemist at Imperial College London in England.


That level of acidity suggests that large-scale volcanic eruptions occurred at the time of the extinction, the researchers said. It'sS long been thought that a key factor behind the end-Permian extinction was cataclysmic volcanic activity in what is now Siberia, which spewed out as much as 2.7 million square miles (7 million square kilometers) of lava, an area nearly as large as Australia.


Three-dimensional computer simulations suggest these eruptions would have pumped out gases that led to intense pulses of acid rain. This would have killed off plant life on land, causing a collapse in the food chain and wreaking global havoc. However, until now, researchers lacked direct evidence of this acidification.


Now there is evidence that acid falling was falling on the ancient supercontinent Pangaea as the result of the volcanic eruptions, killing off end-Permian forests and releasing vanillin from their decaying remains. The acidic soils would have prevented bacteria from converting the vanillin to vanillic acid, and as the soil eroded with the demise of the Permian forests, the vanillin and vanillic acid would have washed with sediments into shallow marine waters.


The findings also suggest that the acidification of the soil occurred not all at once, but rather in repeated pulses of acid rain, the researchers said.


The next step in the research "will be to carry out similar studies on rocks from around the world to confirm the global extent of acidity at the end of the Permian," Sephton said. 

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Dinosaur-killer asteroid nearly wiped out mammals too

Dinosaur-killer asteroid nearly wiped out mammals too | Amazing Science | Scoop.it

The mass extinction event was thought to have paved the way for mammals to dominate, but researchers say many of them died out alongside the dinosaurs. During the Cretaceous period, extinct relatives of living marsupials – such as possums and kangaroos – thrived.


An international team of experts on mammal evolution and mass extinctions has shown that the once-abundant animals – known as metatherian mammals – came close to extinction. A 10-km-wide asteroid struck what is now Mexico at the end of the Cretaceous period, unleashing a global cataclysm of environmental destruction which led to the demise of the dinosaurs.


The study, including the University of Edinburgh scientists, shows that two-thirds of all metatherians living in North America also perished. This included more than 90 per cent of species living in the northern Great Plains of the US, which is the best area in the world for finding latest Cretaceous mammal fossils, researchers said.


Metatherians never recovered their previous diversity, which explains why marsupials are rare today and largely restricted to unusual environments in Australia and South America.


Species that give birth to well-developed live young – known as placental mammals – took full advantage of the metatherians’ demise. Placental mammals – which include many species from mice to men – are ubiquitous across the globe today, researchers said.


“This is a new twist on a classic story. It wasn’t only that dinosaurs died out, providing an opportunity for mammals to reign, but that many types of mammals, such as most metatherians, died out too – this allowed advanced placental mammals to rise to dominance,” said Dr Thomas Williamson from the New Mexico Museum of Natural History and Science.


Researchers reviewed the evolutionary history of metatherians and constructed the most up-to-date family tree for the mammals based on the latest fossil records, allowing them to study extinction patterns in unprecedented detail.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Tooth loss in birds occurred about 116 million years ago

Tooth loss in birds occurred about 116 million years ago | Amazing Science | Scoop.it

The absence of teeth or "edentulism" has evolved on multiple occasions within vertebrates including birds, turtles, and a few groups of mammals such as anteaters, baleen whales and pangolins. Where early birds are concerned, the fossil record is fragmentary. A question that has intrigued biologists is: Based on this fossil record, were teeth lost in the common ancestor of all living birds or convergently in two or more independent lineages of birds? A research team led by biologists at the University of California, Riverside and Montclair State University, NJ, has found an answer. Using the degraded remnants of tooth genes in birds to determine when birds lost their teeth, the team reports in the Dec. 12 issue ofScience that teeth were lost in the common ancestor of all living birds more than 100 million years ago.


"One of the larger lessons of our finding is that 'dead genes,' like the remnants of dead organisms that are preserved in the fossil record, have a story to tell," said Mark Springer, a professor of biology and one of the lead authors of the study along with Robert Meredith at Montclair State University who was previously a graduate student and postdoctoral researcher in Springer's laboratory. "DNA from the crypt is a powerful tool for unlocking secrets of evolutionary history."


Springer explained that edentulism and the presence of a horny beak are hallmark features of modern birds. "Ever since the discovery of the fossil bird Archaeopteryx in 1861, it has been clear that living birds are descended from toothed ancestors," he said. "However, the history of tooth loss in the ancestry of modern birds has remained elusive for more than 150 years."


All toothless/enamelless vertebrates are descended from an ancestor with enamel-capped teeth. In the case of birds, it is theropod dinosaurs. Modern birds use a horny beak instead of teeth, and part of their digestive tract to grind up and process food.

Tooth formation in vertebrates is a complicated process that involves many different genes. Of these genes, six are essential for the proper formation of dentin (DSPP) and enamel (AMTN, AMBN, ENAM, AMELX, MMP20).


The researchers examined these six genes in the genomes of 48 bird species, which represent nearly all living bird orders, for the presence of inactivating mutations that are shared by all 48 birds. The presence of such shared mutations in dentin and enamel-related genes would suggest a single loss of mineralized teeth in the common ancestor of all living birds.


Springer, Meredith, and other members of their team found that the 48 bird species share inactivating mutations in both dentin-related (DSPP) and enamel-related genes (ENAMAMELX, AMTNMMP20), indicating that the genetic machinery necessary for tooth formation was lost in the common ancestor of all modern birds.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

What was Earth's first predator and when did it live?

What was Earth's first predator and when did it live? | Amazing Science | Scoop.it

Around the world right now, thousands of animals are about to die. The game is up for untold numbers of deep-sea fish, mountain-dwelling hares, subterranean earthworms and high-flying songbirds. They are all seconds away from becoming dinner for predators like lions, eagles and sharks.


But when did this carnage begin? Have predators stalked the Earth since the origin of life itself? Or was our primordial planet once a Garden of Eden where species lived in peaceful co-existence?

The truth is, no one actually knows for sure. But evolutionary biologists have learned enough about the history of life on Earth to begin the hunt for the first predator. Their work suggests it was about as far removed in appearance from today's killers as it's possible to imagine.


What sort of traces would the first predator have left behind? We often think of predators using jaws and sharp teeth to rip chunks out of their prey, so maybe we should look for the oldest jaws and teeth. In fact, just last year, we learned thatmodern vertebrate jaws date back 420 million years and that teeth appeared 500 million years ago.


But predators can kill without inflicting physical injury. Think of the predatory pitcher plants that trap, drown and devour insects. So if predators don't need teeth and jaws, they might have appeared long before the 500-million-year mark.


It turns out they really did. Palaeontologists have collected fossils of predators that existed tens of millions of years before teeth evolved. These predators date right back to the first abundant animal life, about 540 million years ago.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Oxygen levels on ancient Earth were key to animal evolution

Oxygen levels on ancient Earth were key to animal evolution | Amazing Science | Scoop.it

Atmospheric oxygen levels during the billion years or so prior to the rise of animals were far too low for complex life forms to develop, according to a new study. The findings, reported in the journal Science, imply that the appearance of diverse animal life on Earth about 800 million years ago, was triggered by increases in oxygen levels - and not just genetic innovations in individual organisms.


"No one really doubted that oxygen levels were low, but how low is the real surprise," says one of the study's authors Dr Peter McGoldrick of the University of Tasmania"Our work shows those levels were just 0.1 per cent of present atmospheric levels, which is significant from an evolutionary point of view because biologists believe that complex multicellular life forms require much more oxygen than 0.1 per cent."


This is the first time anyone has been able to quantify the levels of oxygen in the atmosphere during the mid-Proterozoic period between 0.8 and 1.8 billion years ago, he says.


McGoldrick describes this period in Earth's history as the 'boring billion', when life remained largely constant and unchanging between the appearance of complex cells around 2 billion years ago, and the sudden diversification of multicellular animals about 800 million years ago.


Scientists already knew that oxygen began to accumulate in the atmosphere after cyanobacteria began using photosynthesis to produce oxygen over three billion years ago. So they wondered why animal species didn't flourish during the boring billion year stretch leading up to the end of the Proterozoic, when most researchers thought there was plenty of oxygen.


"We knew oxygen levels had gone up over all, but we didn't know if it had gone up to 1, 10 or 40 per cent of present atmospheric levels," says McGoldrick. "This explains why complex animals don't appear in the rock record until maybe 750 to 800 million years ago, there simply wasn't enough oxygen for the metabolic things they need to do."


Oxygen levels in the atmosphere were determined by examining chromium isotope ratios in ironstone samples. This provided information on oxygen levels for the billion or so years leading up to the 'Cambrian explosion' - when most major animal groups appeared on the planet.

more...
Eric Chan Wei Chiang's curator insight, November 1, 2014 11:42 AM

Climate play a really important role in the evolution of organisms. Makes you wonder how anthropogenic climate change would drive evolution.

 

@Jeff Morris scooped a similar article here: http://sco.lt/60aEUr

 

More scoops about our blue marble can be read here:

http://www.scoop.it/t/aquascaping-and-nature/?tag=Earth+Science

Scooped by Dr. Stefan Gruenwald
Scoop.it!

New evidence of ancient multicellular life sets evolutionary timeline back 60 million years

New evidence of ancient multicellular life sets evolutionary timeline back 60 million years | Amazing Science | Scoop.it

A Virginia Tech geobiologist with collaborators from the Chinese Academy of Sciences have found evidence in the fossil record that complex multicellularity appeared in living things about 600 million years ago – nearly 60 million years before skeletal animals appeared during a huge growth spurt of new life on Earth known as the Cambrian Explosion.

The discovery published online Wednesday in the journal Nature contradicts several longstanding interpretations of multicellular fossils from at least 600 million years ago.


"This opens up a new door for us to shine some light on the timing and evolutionary steps that were taken by multicellular organisms that would eventually go on to dominate the Earth in a very visible way," said Shuhai Xiao, a professor of geobiology in the Virginia Tech College of Science. "Fossils similar to these have been interpreted as bacteria, single-cell eukaryotes, algae, and transitional forms related to modern animals such as sponges, sea anemones, or bilaterally symmetrical animals. This paper lets us put aside some of those interpretations."


In an effort to determine how, why, and when multicellularity arose from single-celled ancestors, Xiao and his collaborators looked at phosphorite rocks from the Doushantuo Formation in central Guizhou Province of South China, recovering three-dimensionally preserved multicellular fossils that showed signs of cell-to-cell adhesion, differentiation, and programmed cell death—qualities of complex multicellular eukaryotes such as animals and plants.


The discovery sheds light on how and when solo cells began to cooperate with other cells to make a single, cohesive life form. The complex multicellularity evident in the fossils is inconsistent with the simpler forms such as bacteria and single-celled life typically expected 600 million years ago.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Early Earth less hellish than previously thought

Early Earth less hellish than previously thought | Amazing Science | Scoop.it

Conditions on Earth for the first 500 million years after it formed may have been surprisingly similar to the present day, complete with oceans, continents and active crustal plates.


This alternate view of Earth’s first geologic eon, called the Hadean, has gained substantial new support from the first detailed comparison of zircon crystals that formed more than 4 billion years ago with those formed contemporaneously in Iceland, which has been proposed as a possible geological analog for early Earth.


The study was conducted by a team of geologists directed by Calvin Miller, the William R. Kenan Jr. Professor of Earth and Environmental Sciences at Vanderbilt University, and published online this weekend by the journal Earth and Planetary Science Letters in a paper titled, “Iceland is not a magmatic analog for the Hadean: Evidence from the zircon record.”


From the early 20th century up through the 1980’s, geologists generally agreed that conditions during the Hadean period were utterly hostile to life. Inability to find rock formations from the period led them to conclude that early Earth was hellishly hot, either entirely molten or subject to such intense asteroid bombardment that any rocks that formed were rapidly remelted. As a result, they pictured the surface of the Earth as covered by a giant “magma ocean.”


Two schools of thought have emerged: One argues that Hadean Earth was surprisingly similar to the present day. The other maintains that, although it was less hostile than formerly believed, early Earth was nonetheless a foreign-seeming and formidable place, similar to the hottest, most extreme, geologic environments of today. A popular analog is Iceland, where substantial amounts of crust are forming from basaltic magma that is much hotter than the magmas that built most of Earth’s current continental crust.


“We reasoned that the only concrete evidence for what the Hadean was like came from the only known survivors: zircon crystals – and yet no one had investigated Icelandic zircon to compare their telltale compositions to those that are more than 4 billion years old, or with zircon from other modern environments,” said Miller.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Paleontologists just found the dinosaur Dreadnoughtus, an 85-foot-long titan - the most massive ever discovered

Paleontologists just found the dinosaur Dreadnoughtus, an 85-foot-long titan - the most massive ever discovered | Amazing Science | Scoop.it

Today an international team of paleontologists unveiled the newest Mesozoic giantDreadnoughtus schrani. Weighing in at an astonishing 65 tons, standing two stories high at the shoulder, and measuring 85 feet long, this titan is the heaviest dinosaur we've ever (accurately) measured. And its discovery represents the most fossil mass ever found for a single organism—a paleontologist's dream. 

"For the largest dinosaurs, which we call titanosaurs, finding anything around 20 percent of the fossil is usually considered a home run," says Kenneth Lacovara, the lead Drexel University paleontologist behind the find. "Normally you only find a handful of bones, and the previous record was a 27 percent complete skeleton. With Dreadnoughtus we found 70 percent." 

Near-Complete: The reason near-complete finds are so rare is because fossilization requires a quick burial in sediment. As you can imagine, it's an extraordinary occurrence for something as big as a Dreadnoughtus to be buried so quickly. But according to Lacovara, the scientists believe a rapid pair of floods, caused by broken earthen levees in the valley where Dread was found, are behind the impressively complete find. Sedimentary records in nearby areas back up this idea.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

The dead walk again: An arachnid that lived 410 million years ago has crawled back into the virtual world

The dead walk again: An arachnid that lived 410 million years ago has crawled back into the virtual world | Amazing Science | Scoop.it

A spider-like creature's remains were so well preserved in fossil form that scientists could see all its leg joints, allowing them to recreate its likely gait using computer graphics.


Known as a trigonotarbid, the animal was one of the first predators on land. Its prey were probably early flightless insects and other invertebrates, which it would run down and jump on.


"We know quite a bit about how it lived," said Russell Garwood, a palaeontologist with the University of Manchester, UK. "We can see from its mouth parts that it pre-orally digested its prey - something that most arachnids do - because it has a special filtering plate in its mouth. So, that makes us fairly sure it vomited digestive enzymes on to its prey and then sucked up liquid food," he explained.


The trigonotarbid specimens studied by Dr Garwood and colleagues are just a few millimetres in length. They were unearthed in Scotland, near the Aberdeenshire town of Rhynie. Its translucent Early Devonian chert sediments are renowned for their exquisite fossils.


The team used a collection held at the Natural History Museum in London that have actually been prepared since the 1920s. The rock had been cut into extremely fine slices just a few tens of microns thick, making it possible to construct 3D models of the arachnids, much like a doctor might do with the X-ray slices obtained in a CAT scan.


"We could see the articulation points in the legs," explained Dr Garwood. "Between each part of the leg, there are darker pieces where they join, and that allowed us to work out the range of movement.


"We then compared that with the gaits of modern spiders, which are probably a good analogy because they have similar leg proportions. The software enabled us to see the centre of mass and find a gait that worked. If it's too far back compared to the legs, the posterior drags on the ground. The trigonotarbid is an alternating tetrapod, meaning there are four feet on the ground at any one time."


"This new study has gone further and shows us how they probably walked. For me, what's really exciting here is that scientists themselves can make these animations now, without needing the technical wizardry (and immense costs) of a Jurassic-Park style film. When I started working on fossil arachnids, we were happy if we could manage a sketch of what they used to look like. Now, they run across our computer screens."


The work is part of a special collection of papers on 3D visualisations of fossils published in the Journal of Paleontology.


more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

New to Google Earth: Ancient Flying Reptiles Database and Mapping Tool

New to Google Earth: Ancient Flying Reptiles Database and Mapping Tool | Amazing Science | Scoop.it

A newly developed website catalogs more than 1,300 specimens of extinct flying reptiles called pterosaurs, thus enabling users to map out the ancient creatures on Google Earth. The goal is to help researchers find trends in the evolution and diversity of theseancient winged reptiles.


"Having a very specific database like this, which is just for looking at individual fossil specimens of pterosaurs, is very helpful, because you can ask questions that you couldn't have answered with bigger databases [of more animals]," said Matthew McLain, a doctoral candidate in paleontology at Loma Linda University in California and one of the three developers of the site. McLain and his colleagues call their database PteroTerra


Pterosaurs were the first flying vertebrates. They lived between 228 million and 66 million years ago, and went extinct around the end of the Cretaceous period. During that time, this group evolved to be incredibly diverse. Some were tiny, like the sparrow-size Nemicolopterus crypticus, which lived 120 million years ago in what is now China. Others were simply huge, like Quetzalcoatlus, which was as tall as a giraffe and probably went around spearing little dinosaurs with its beak like a stork might snack on frogs.

Paleontological databases are common tools, because they allow researchers to navigate through descriptions of fossil specimens. One of the largest, the Paleobiology Database, has more than 50,000 individual entries.


McLain and his colleagues wanted something more targeted. They painstakingly built PteroTerra from the ground up. McLain, as the paleontologist on the project, read published papers on pterosaurs and visited museums to catalog specimens.


"I think we have every species represented, so in that sense, it's pretty complete," he told Live Science. The database does not contain every specimen of pterosaur material ever found — tens of thousands of fossil fragments have been discovered — but McLain hopes to get other paleontologists on board as administrators to upload their specimen data.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Amber discovery indicates Lyme disease is older than human race

Amber discovery indicates Lyme disease is older than human race | Amazing Science | Scoop.it
Lyme disease is a stealthy, often misdiagnosed disease that was only recognized about 40 years ago, but new discoveries of ticks fossilized in amber show that the bacteria which cause it may have been lurking around for 15 million years -- long before any humans walked on Earth. The findings were made by researchers who studied 15-20 million-year-old amber from the Dominican Republic that offer the oldest fossil evidence ever found of Borrelia, a type of spirochete-like bacteria that to this day causes Lyme disease.


"Ticks and the bacteria they carry are very opportunistic," said George Poinar, Jr., a professor emeritus in the Department of Integrative Biology of the OSU College of Science, and one of the world's leading experts on plant and animal life forms found preserved in amber. "They are very efficient at maintaining populations of microbes in their tissues, and can infect mammals, birds, reptiles and other animals.


"In the United States, Europe and Asia, ticks are a more important insect vector of disease than mosquitos," Poinar said. "They can carry bacteria that cause a wide range of diseases, affect many different animal species, and often are not even understood or recognized by doctors. "It's likely that many ailments in human history for which doctors had no explanation have been caused by tick-borne disease."


Lyme disease is a perfect example. It can cause problems with joints, the heart and central nervous system, but researchers didn't even know it existed until 1975. If recognized early and treated with antibiotics, it can be cured. But it's often mistaken for other health conditions. And surging deer populations in many areas are causing a rapid increase in Lyme disease -- the confirmed and probable cases of Lyme disease in Nova Scotia nearly tripled in 2013 over the previous year.


The new research shows these problems with tick-borne disease have been around for millions of years.


more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Longer than a Blue Whale: 'Biggest Dinosaur ever' Discovered

Longer than a Blue Whale: 'Biggest Dinosaur ever' Discovered | Amazing Science | Scoop.it

Fossilized bones of a dinosaur believed to be the largest creature ever to walk the Earth have been unearthed in Argentina, paleontologists say. Based on its huge thigh bones, it was 40m (130ft) long and 20m (65ft) tall. Weighing in at 77 tonnes, it was as heavy as 14 African elephants, and seven tonnes heavier than the previous record holder, ArgentinosaurusScientists believe it is a new species of titanosaur - an enormous herbivore dating from the Late Cretaceous period. A local farm worker first stumbled on the remains in the desert near La Flecha, about 250km (135 miles) west of Trelew, Patagonia. The fossils were then excavated by a team of paleontologists from the Museum of Palaeontology Egidio Feruglio, led by Dr Jose Luis Carballido and Dr Diego Pol. They unearthed the partial skeletons of seven individuals - about 150 bones in total - all in "remarkable condition".

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Snakes are 70 million years older than scientists previously thought

Snakes are 70 million years older than scientists previously thought | Amazing Science | Scoop.it

A new look at four fossils has revealed that snakes’ earliest known ancestor lived as many as 70 million years earlier than thought, scientists said Tuesday. Until now, the fossil record had suggested snakes slithered onto the scene in the Upper Cretaceous period, about 94-100 million years ago.


But an international team of researchers reported in the journal Nature Communications that serpents actually have a much longer lineage. Evolution of ‘snakes’ is much more complex than previously thought,” Michael Caldwell, a professor at the University of Alberta in Canada, said in a press release. Re-analysing fossils in museum collections, the scientists found that the oldest among them belonged to the earliest identifiable snake, which lived between 143 and 167 million years ago.


The granddaddy is a critter dubbed Eophis underwoodi, after Garth Underwood, an expert at Britain’s Natural History Museum, who wrote an important reference work on snakes in the 1960s. E. underwoodi lived in the Middle Jurassic period, during the final stage of an important event in Earth’s geological history — the breakup of the Pangaea supercontinent into two components called Gondwana and Laurasia.


It, and the three other ancient fossils, suggest that snakes by this time had already differentiated from their lizard cousins, the study says.

The big giveaway is the skull, which remains almost unchanged among snakes to this day.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

In fossilized fish eye, rods and cones are preserved for 300 million years

In fossilized fish eye, rods and cones are preserved for 300 million years | Amazing Science | Scoop.it
Scientists have discovered a fossilized fish so well preserved that the rods and cones in its 300-million-year-old eyeballs are still visible under a scanning electron microscope.


It is the first time that fossilized photoreceptors from a vertebrate eye have ever been found, according to a paper published Tuesday in Nature Communications. The researchers say the discovery also suggests that fish have been seeing the world in color for at least 300 million years. Rods and cones are cells that line the retina in our eyes. Rods are long and thin, and more sensitive to light than cones. However, cones, which are triangular, allow us to see in color. Both these cells rely on pigments to absorb light. Using chemical analysis, the scientists found evidence of one of these pigments -- melanin -- in the fossilized eye as well.


The fish pictured above is about 10 centimeters long. It was found in the Hamilton Quarry in Kansas, which was once a shallow lagoon. Fossils from this area are remarkably well preserved because they were buried very quickly in sediments in the lagoon, said Gengo Tanaka of Kumamoto University in Japan, the lead author of the paper.  In the case of this fish, an extinct species called Acanthodes bridgei, the preservation process probably also got some help from bacterial activity that left a thin film of phosphate over the eyes before it was buried.  Tanaka said that gills and pigments on other parts of the fish were also preserved. However, he had not looked to see whether organs and nerves were intact as well.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Celestial impacts, mass extinctions and climate change in the search for life elsewhere

Celestial impacts, mass extinctions and climate change in the search for life elsewhere | Amazing Science | Scoop.it
Every so often our Earth encounters a large chunk of space debris which reminds us that our solar system still contains plenty of debris that could potentially have an impact on life on Earth.


While the great bulk of planetary accretion occurs in the first few hundred million years after the birth of a given system, the process never really comes to an end. Most of the objects that make up the tail of this accretion – grains of dust, lumps of ice, and pieces of rock – smash into our atmosphere and ablate harmlessly many kilometres above the ground, visible only as shooting stars. Larger impacts do, however, continue to occur – as illustrated on February 15, 2013, in the Russian city of Chelyabinsk. On that day, with no warning, a small near-Earth asteroid detonated in the atmosphere, and outshone the noon-day sun.


Though the object itself was relatively small, around 20m in diameter, it exploded with sufficient force to shatter windows many kilometres away, damaging more than 7,000 buildings. Amazingly, nobody was killed – but the impact served as a stark reminder of the dangers posed by rocks from space. The longer the timescale we consider, the larger the biggest collision the Earth might experience. A stand-out example is the impact, around 65 million years ago, thought to have contributed to the extinction of the dinosaurs.


Fortunately for us here on Earth, the rate at which such catastrophic impacts occur is relatively low, but this might not be the case in other planetary systems. Thanks to observations carried out at infrared wavelengths, we are now in a position to start categorising the small object populations of other planetary systems. As we do, we are finding that many systems contain far more debris, left over from their formation, than does our own. This gives us an additional tool by which we can assess potentially habitable planets. It should be possible to estimate the impact regimes that they might experience, based on these kind of observations.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Rival species recast significance of ‘first bird’ Archaeopteryx

Rival species recast significance of ‘first bird’ Archaeopteryx | Amazing Science | Scoop.it

The iconic status of Archaeopteryx, the first animal discovered with both bird and dinosaur features, is under attack. More-recently discovered rival species show a similar mix of traits. As the simplistic idea of a ‘first’ bird gives way to a messy evolutionary transition, newly discovered fossils and improved analysis techniques put Archaeopteryx in prime position to unravel the details. “Research on Archaeopteryx is really catching a new breath,” says palaeobiologist Martin Kundrat of Uppsala University in Sweden.


The first Archaeopteryx fossil specimens turned up in limestone quarries in Bavaria, southern Germany, in the early 1860s. Until recently, they were the only fossil specimens found to mix bird- and dinosaur-like features. On the one hand, they are small — the fossils show juvenile creatures about the size of a magpie, which as adults may have been raven-sized — and have broad feathered wings that look good for gliding; on the other, they have a jaw with sharp teeth, dinosaur-like claws and a bony tail. These features led to the idea of the first bird, and generations of scientists have treated the 145-million-year-old animal as a ‘transitional species’ — the key piece of evidence linking birds and dinosaurs (Archaeopteryx is Greek for ‘ancient feather’, whereas its German name, Urvogel, means ‘first bird’).


But starting in the 1990s, the unique status of Archaeopteryx faced a challenge from the discovery in China of other potential transitional species. Fossils of Anchiornis huxleyi and Microraptor xuireveal small-bodied creatures like Archaeopteryx, and they may have used their four wings to glide. Another, Aurornis xui, has legs, claws and a tail similar to those of Archaeopteryx, yet lived about 10 million years earlier, leading some to propose it as a better candidate for first bird (see‘The fight for first bird’).


Many scientists now believe that Archaeopteryx is just another dinosaur. Others find this hard to swallow. “To some ornithologists this is a really big deal — Archaeopteryx is the first bird,” says Gareth Dyke, a vertebrate palaeontologist at the University of Southampton, UK. “They’d rather cut off one of their legs than admit it has nothing to do with bird origins.”

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

40,000-year-old blood brings mammoth cloning closer

40,000-year-old blood brings mammoth cloning closer | Amazing Science | Scoop.it
Mammoth cloning is closer to becoming a reality following the discovery of blood in the best-preserved specimen ever found.


An autopsy on a 40,000-year-old mammoth has yielded blood that could contain enough intact DNA to make cloning possible, galvanising scientists who have been working for years to bring back the extinct elephant relative. Tests are still being conducted on the blood to see if it will yield a complete genome – the genetic code necessary to build an organism.


The mammoth (nicknamed Buttercup) was discovered in 2013 on Maly Lyakhovsky Island in northern Siberia and excavated from the permafrost. The flesh was remarkably well-preserved, and oozed a dark red liquid when scientists cut into it. That liquid has now been confirmed as blood, following an autopsy conducted by scientists including Museum palaeobiologist Dr Tori Herridge.


'As a palaeontologist, you normally have to imagine the extinct animals you work on,' said Dr Herridge. 'So actually coming face-to-face with a mammoth in the flesh, and being up to my elbows in slippery, wet, and frankly rather smelly mammoth liver, counts as one of the most incredible experiences of my life.' The South Korean firm Sooam Biotech Research Foundation is leading the research project.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Fossilized Nuclei and Chromosomes Reveal 180 Million Years of Genomic Stasis in Royal Ferns

Fossilized Nuclei and Chromosomes Reveal 180 Million Years of Genomic Stasis in Royal Ferns | Amazing Science | Scoop.it

It defies belief, but a 180 million year old fern fossil unearthed in Sweden is so exquisitely preserved that it is possible to see its cells dividing. So pristine is the fossil, reported scientists from the Swedish Museum of Natural History in the journal Science in March, that it is possible for them to estimate its genome size from the size of its cell nuclei — and that it has remained substantially unchanged from its living descendants since the early Jurassic.


The ferns were swallowed by a volcanic mudflow called a lahar, in which gas and rocky debris from an eruption mix with water and sediment. After entombment, hot salty water percolated into the coarse sediments around the ferns and acted as a preservative brine that immortalized the hapless plants. Their misfortune was our luck: 180 million years later, we can see details of their macro and micro anatomy so well that we can see how uncannily similar they are to their living descendants, royal and cinnamon ferns. They could be sisters!


Fossils from the family this fern belongs to had already been found from 220 million year-old rocks that were recognizable as the living species Osmunda claytonia — the interrupted fern — and other fossils from the Mesozoic have been found that are virtually indistinguishable from other genera and species in the fern’s family, the Osmundaceae (the royal ferns). But microscopic preservation of this quality has rarely been seen in any fossils before.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Fossil evidence of limb regeneration in 300 million year old amphibian

Fossil evidence of limb regeneration in 300 million year old amphibian | Amazing Science | Scoop.it

A trio of researchers with Germany's Museum für Naturkunde, Leibniz-Institut für Evolutions und Biodiversitätsforschung, has found evidence of limb regeneration in a 300 million year old amphibian fossil, which suggests that the ability to regenerate entire limbs by such creatures is not restricted to modern salamanders. In their paper published in Proceedings of the Royal Society B: Biological Sciences, Nadia Fröbisch, Constanze Bickelmann and Florian Witzmann describe the fossil they've been studying and why they believe it was able to regenerate its limbs.


Scientists believe that salamanders are the only modern four-legged animals that can regenerate entire limbs throughout their lives. What's not clear, however, despite a great deal of research, is if the ability is a recent evolutionary trait or if it came about long ago and has been passed along for many years. The findings by the researchers with this latest effort suggest the latter—the fossil appears to be an ancient relative of the salamander.


The researchers note that when modern salamanders lose a limb, the replacement that grows back doesn't always look just like the original—sometimes there are odd bumps or scars or digits fused back together. This is particularly so if a salamander looses the same limb more than once. In examining the amphibian fossil, (Micromelerpeton, found in northwest Germany) the researchers found the same odd characteristic in the toes—there was an extra partly fused one, suggesting very strongly that the creature had lost a toe and had re-grown a replacement.


Finding regenerative ability in such an ancient creature begs the question of why more tetrapod species don't have the ability today. The researchers suggest that the ability to re-grow lost limbs was perhaps lost over time or evolved into something else entirely as it became a trait that was no longer needed, or because it took up too much resources.


Gaining an evolutionary perspective on limb regeneration might help researchers in other areas that are attempting to find out if limb replacement can be caused to come about in other animals, particularly humans, through some unknown mechanism. Learning how salamanders developed the ability might help modern researchers repeat the process.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Microscopic Diamonds Suggest Cosmic Impact Responsible for Younger Dryas Climate Change 12,800 Years Ago

Microscopic Diamonds Suggest Cosmic Impact Responsible for Younger Dryas Climate Change 12,800 Years Ago | Amazing Science | Scoop.it

A new study published in The Journal of Geology provides support for the theory that a cosmic impact event over North America some 13,000 years ago caused a major period of climate change known as the Younger Dryas stadial, or “Big Freeze.”

 

Around 12,800 years ago, a sudden, catastrophic event plunged much of the Earth into a period of cold climatic conditions and drought. This drastic climate change—the Younger Dryas—coincided with the extinction of Pleistocene megafauna, such as the saber-tooth cats and the mastodon, and resulted in major declines in prehistoric human populations, including the termination of the Clovis culture.

 

With limited evidence, several rival theories have been proposed about the event that sparked this period, such as a collapse of the North American ice sheets, a major volcanic eruption, or a solar flare.

 

However, in a study published in The Journal of Geology, an international group of scientists analyzing existing and new evidence have determined a cosmic impact event, such as a comet or meteorite, to be the only plausible hypothesis to explain all the unusual occurrences at the onset of the Younger Dryas period.

 

Researchers from 21 universities in 6 countries believe the key to the mystery of the Big Freeze lies in nanodiamonds scattered across Europe, North America, and portions of South America, in a 50-million-square-kilometer area known as the Younger Dryas Boundary (YDB) field.

 

Microscopic nanodiamonds, melt-glass, carbon spherules, and other high-temperature materials are found in abundance throughout the YDB field, in a thin layer located only meters from the Earth’s surface. Because these materials formed at temperatures in excess of 2200 degrees Celsius, the fact they are present together so near to the surface suggests they were likely created by a major extraterrestrial impact event.

 

In addition to providing support for the cosmic impact event hypothesis, the study also offers evidence to reject alternate hypotheses for the formation of the YDB nanodiamonds, such as by wildfires, volcanism, or meteoric flux.

 

The team’s findings serve to settle the debate about the presence of nanodiamonds in the YDB field and challenge existing paradigms across multiple disciplines, including impact dynamics, archaeology, paleontology, limnology, and palynology.

 

more...
Bernhard H. Schmitz's curator insight, September 16, 2014 6:33 AM

And where is the center of the YDB field?

Scooped by Dr. Stefan Gruenwald
Scoop.it!

Dinosaurs shrank to evolve into birds over a 50 million years time span

Dinosaurs shrank to evolve into birds over a 50 million years time span | Amazing Science | Scoop.it

Huge meat-eating dinosaurs (Theropods) underwent 12 stages of miniaturization and shrank steadily over 50 million years to evolve into small, flying birds, researchers say. The branch of theropod dinosaurs which gave rise to modern birds decreased inexorably in size from 163kg beasts that roamed the land, to birds weighing less than 1kg over the period.


The radical transformation began around 200 million years ago and was likely driven by a move to the trees where creatures with smaller, lighter bodies and other features, such as large eyes for 3D vision, fared better than others.


Scientists pieced together the dinosaurs' sustained shrinkage after analysing more than 1,500 anatomical features of 120 species of theropods and early birds.


The evolutionary tree reveals that the theropod ancestors of modern birds underwent 12 substantial decreases in size that led to archaeopteryx, the earliest known bird on Earth. The rate at which they evolved distinct features, such as feathers, wings and wishbones, was four times faster than adaptations in other dinosaurs.


"Birds evolved through a unique phase of sustained miniaturisation in dinosaurs," said Michael Lee at the University of Adelaide. "Being smaller and lighter in the land of giants, with rapidly evolving anatomical adaptations, provided these bird ancestors with new ecological opportunities, such as the ability to climb trees, glide and fly. Ultimately, this evolutionary flexibility helped birds survive the deadly meteorite impact which killed off all their dinosaurian cousins," he added. The study is published in the journal, Science.


The steady reduction in size saw the two-legged land-based theropods evolve new bird-like features, including shorter snouts, smaller teeth and insulating feathers.


Gareth Dyke, a vertebrate palaeontologist and co-author of the study at Southampton University said: "The dinosaurs most closely related to birds are all small, and many of them, such as the aptly named Microraptor, had some ability to climb and glide."


In an accompanying article, Michael Benton at Bristol University, said that the long-term trend that led to modern birds was probably shaped by the animals taking up in new habitats. "The crucial driver may have been a move to the trees, perhaps to escape from predation or to exploit new food resources," he writes.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Newly declared species may have been the largest flying bird that ever lived

Newly declared species may have been the largest flying bird that ever lived | Amazing Science | Scoop.it
After decades with the title, an extinct bird loses its claim to the widest wing span in history.


When South Carolina construction workers came across the giant, winged fossil at the Charleston airport in 1983, they had to use a backhoe to pull the bird, which lived about 25 million years ago, up from the earth.


But if the bird was actually a brand-new species, researchers faced a big question: Could such a large bird, with a wingspan of 20 to 24 feet, actually get off the ground? After all, the larger the bird, the less likely its wings are able to lift it unaided.


The answer came from Dan Ksepka, paleontologist and science curator at the Bruce Museum in Greenwich, Conn.


He modeled a probable method of flight for the long-extinct bird, named as a new species this week in the Proceedings of the National Academy of Sciences. If Ksepka’s simulations are correct, Pelagornis sandersi would be the largest airborne bird ever discovered.


Pelagornis sandersi relied on the ocean to keep it aloft. Similar in many ways to a modern-day albatross — although with at least twice the wingspan and very different in appearance, Ksepka said — the bird probably needed a lot of help to fly. It had to run downhill into a head wind, catching the air like a hang glider. Once airborne, it relied on air currents rising from the ocean to keep it gliding.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

Fossilized nuclei and chromosomes of 180 million-year-old fern nearly identical to modern relative

Fossilized nuclei and chromosomes of 180 million-year-old fern nearly identical to modern relative | Amazing Science | Scoop.it

A trio of researchers in Sweden has unearthed a fossilized fern that has been dated to 180 million years ago, that remarkably, is in near pristine condition. Benjamin Bomfleur and Stephen McLoughlin, of the Swedish Museum of Natural History and Vivi Vajda of Lund University, report in their paper published in the journal Science that they discovered the fossil in a bed of volcanic rock near Korsaröd in Sweden, and found it so well preserved that microscopic analysis revealed that they could make out its DNA structure.


The calcified stem of a royal fern dating back to the early Jurassic period was apparently preserved by mineral precipitation from hydrothermal brines as they rapidly crystalized, trapping the fern, which was clearly alive at the time, encasing it in an airtight environment. Although very small (just 5.8 x 4.1 cm) the fossil was so well preserved that the researchers were still able to make out cell cytoplasm, nuclei and even chromosomes.


Curious, the team measured the sub-cellular parts of the fossilized plant and compared them to those of a modern relative, the cinnamon fern (Osmundastrum cinnamomeum), which has already earned the title of a "living fossil" due to prior research that revealed its origins could be dated back to 75 million years ago. In so doing they discovered that the number of chromosomes and indeed the DNA content itself was a very close match—so close that the team dubbed them a "paramount example of evolutionary stasis." Remarkably, the plant hasn't changed much at all over a period of 180 million years. When it lived, it likely looked much like the bright green cinnamon fern (though they turn to cinnamon color later in life) of today, growing to a height of one to five feet with spreading fronds reaching six to eight inches. The team suggests the specimen provides exceptional insight into how life can evolve over geologic time.

more...
No comment yet.
Scooped by Dr. Stefan Gruenwald
Scoop.it!

When Trilobites Ruled the World

When Trilobites Ruled the World | Amazing Science | Scoop.it
The remains of trilobites, a diverse group of marine animals much older than dinosaurs, are remarkably well preserved, providing fresh insights of their anatomies and social behavior.


Trilobites may be the archetypal fossils, symbols of an archaic world long swept beneath the ruthless road grader of time. But we should all look so jaunty after half a billion years.


At the Smithsonian’s National Museum of Natural History, Brian T. Huber, chairman of paleobiology, points to a flawless specimen of Walliserops, a five-inch trilobite that swam the Devonian seas around what is now Morocco some 150 million years before the first dinosaurs hatched. With its elongated, triple-tined head horn and a bristle brush of spines encircling its lower body, the trilobite could be a kitchen utensil for Salvador Dalí. Nearby is the even older Boedaspis ensifer, its festive nimbus of spiny streamers pointing every which way like the ribbons of a Chinese dancer.


In most trilobites, each compound orb held hundreds of tiny calcite lenses, arranged in a tightknit honeycomb pattern, like the eye of a fly. But fairly late in trilobite evolution one group developed a different sort of eye, composed of a smaller number of larger, separated calcite lenses. As they described last spring in the journal Scientific ReportsBrigitte Schoenemann of the Universities of Cologne and Bonn in Germany and Euan N. K. Clarkson of the University of Edinburgh, used advanced scanning techniques, including synchrotron radiation, to examine specimens of these later, larger-lensed trilobite eyes. On the back of the lenses, the scientists were astonished to see traces of the sensory receptor cells that once linked the eyes to the brain. “It was extraordinary,” Dr. Schoenemann said. “As far as we know, these are the oldest receptor cells that have ever been seen in any fossil animal.”


Analyzing the microstructure of the receptor tracings, the researchers concluded that the eyes were designed to work optimally in lowlight, murky conditions, a sign that some trilobites were turning reclusive, descending to deeper waters or burrowing farther into the mud to escape the proliferation of toothy marine predators and new crustacean competitors. Toward the end of the Paleozoic Era, the once-thriving trilobite tribe had been reduced to a scattering of species. And they, too, vanished in the great Permian extinction 252 million years ago.


more...
No comment yet.