Study reveals new clues about Great Dying, Earth’s largest mass extinction

A new study sheds light on the potential cause of the End-Permian Extinction 250 million years ago.

A new study sheds light on the causes of the largest mass extinction in the Earth’s history, also referred to as the End-Permian Extinction and the Great Dying.

The event took place approximately 250 million years ago when a giant volcanic eruption hit what is now Russia’s province of Siberia. The eruption sent almost 90 percent of life into extinction. In geology, the eruption is referred to as the Siberian Flood Basalts, which ran for nearly one million years.

“The scale of this extinction was so incredible that scientists have often wondered what made the Siberian Flood Basalts so much more deadly than other similar eruptions,” said Michael Broadley of the Centre for Petrographic and Geochemical Research in Vandœuvre-lès-Nancy, France, and lead author of the study.

The research was co-authored by the late Lawrence Taylor, who is the former director of the Planetary Geosciences Institute at the University of Tennessee, Knoxville.

“Taylor was instrumental in supplying samples of mantle xenoliths, rock sections of the lithosphere [a section of the planet located between the crust and the mantle] that get captured by the passing magma and erupted to the surface during the volcanic explosion,” Broadley said. “Taylor also provided advice throughout the study.”

The team analyzed samples to determine the lithosphere composition, which revealed that prior to the Siberian Basalt floods, it was loaded with bromine, iodine, and chlorine, all of which belong to the halogen chemical group. After the volcanic eruption, they disappeared.

“We concluded that the large reservoir of halogens that was stored in the Siberian lithosphere was sent into the earth’s atmosphere during the volcanic explosion, effectively destroying the ozone layer at the time and contributing to the mass extinction,” Broadley said.

The findings were published in Nature Geoscience.

New model identifies main factors that shaped evolution

Scientists have created a new model that attempts to identify the primary influences of evolution and climate change.

A new computer simulation takes into account the numerous factors that drive evolutionary extinction and adaptation. The study outlining the model attempts to bring us closer to understanding the complex interactions between climate change and topography, and how these interactions affect the biodiversity and evolutionary histories of species in their natural ecosystems.

“We had hoped to be able to model in the simulation the most fundamental processes that shape the geography of life on Earth,” said Robert Colwell, who led the research with Brazilian colleague Thiago F. Rangel in collaboration with Neil Edwards and Philip Holden in the United Kingdom.

To create their model, the team looked to South America, which is the most biologically diverse continent on the planet. And since the Andes mountain range started developing 25 million years ago, it created an extremely varied landscape that gave rise to a plethora of biodiversity, making it a perfect area to study the evolution and ecology of biodiversity.

“The Andes are the longest mountain range on Earth, and the only trans-tropical one,” Rangel said. “They sit right beside the Amazon, the planet’s largest tropical rainforest and river basin. This is the reason South America has such exuberant biodiversity.”

“Our results demonstrate how intimately the evolution of life depends on the changing physical environment,” said Neil Edwards of The Open University modelling team.

The model comes at a time of unprecedented climate change, highlighting the unique and dynamic power of climate change and the many ways it shapes the evolution of life on Earth.

“The current pace of human driven climate change is much, much faster than anything in our model, but the same processes are happening in terms of species’ range shifts today,” Colwell said.

The findings were published in Science.

Geologists say we’re now living in the Meghalayan Age

Geologists claim that human civilization is now in the Meghalayan Age.

Geologists just redefined the last 4,200 years of human civilization as the Meghalayan Age. The new classification will reportedly help scientists understand the events that have taken place over the last few-thousand years.

The announcement came from the International Commission on Stratigraphy and indicates significant changes in the Earth and its geologic record. For example, the devastating drought that occurred 4,200 years ago left a geologic imprint. One example is found in the rock record of stalagmites in India in the form of changes in oxygen isotopes.

“The Meghalayan Age is unique among the many intervals of the Geologic Time Scale in that its beginning coincides with a global cultural event produced by a global climatic event,” said Dr. Stanley Finney of the International Union of Geological Sciences (IUGS).

“The convergence of stratigraphy and human cultural evolution is extraordinary,” said Martin Head, a geologist at Brock University in Canada.

However, not all scientists agree that new ages are helpful in reclassifying recent history.

“They’ve suddenly announced [the Meghalayan] and stuck it on the diagram,” said  geography professor Mark Maslin. “It’s official, we’re in a new age; who knew? We have lots of new definitions that perhaps now contradict the Anthropocene Working Group and go against what most scientists perceive to be the most important change on Earth in the last 10,000 years.”

But others suggest that it might be possible for the Meghalayan and Anthropocene to exist simultaneously, and emphasize how difficult it is to precisely define the latter period. Time will tell how the debate plays out.

Cold climates contributed to Neanderthal extinction, study says

A new study suggests that climate change, and cold climates in particular, probably contributed to Neanderthal extinction.

A new study suggests that climate change likely played a bigger role in the extinction of Neanderthals than we thought. The effort was a collaboration between many American and European research institutions and created detailed new natural records from stalagmites that reveal changes in the European climate over 40,000 years ago.

In particular, many of the cold periods coincide with many of the periods with no archaeological Neanderthals artifacts, which suggests that climate changes impact the long-term survival of the species.

“The Neanderthals were the human species closest to ours and lived in Eurasia for some 350,000 years,” said Vasile Ersek, co-author of the study. “However, around 40,000 years ago — during the last Ice Age and shortly after the arrival of anatomically modern humans in Europe — they became extinct.”

“For many years we have wondered what could have caused their demise,” he added. “Were they pushed ‘over the edge’ by the arrival of modern humans, or were other factors involved? Our study suggests that climate change may have had an important role in the Neanderthal extinction.”

The team believes that modern humans were able to survive these cold periods due to better adaptation to the environment.

“The comparable timing of stadials and population changes seen in the archaeologic and genetic record suggests that millennial-scale hostile climate intervals may have been the pacesetter of multiple depopulation-repopulation cycles” Ersek said. “These cycles ultimately drew the demographic map of Europe’s Middle-Upper Paleolithic transition.”

The findings were published in the Proceedings of the National Academy of Sciences.

Genetic legacy of first dogs lives on in sexually transmitter cancer

The DNA of the first domesticated dogs of the Americas lives on in a sexually transmitter cancer.

A new study suggests that the domesticated dogs that firsts traveled to the Americas were brought by humans that were migrating from Asia. And although they were eventually wiped out in the 15th century, their genetic legacy appears to live on as a sexually transmitter cancer.

The cancer is called canine transmissible venereal tumor (CTVT) and has spread around the world. It is essentially a mutated version of animal DNA, which was traced back to the first domesticated American dogs.

“It’s quite incredible to think that possibly the only survivor of a lost dog lineage is a tumor that can spread between dogs as an infection,” said Maire Ní Leathlobhair, a researcher from the Department of Veterinary Medicine at the University of Cambridge and co-lead author of the study.

Although the examination into the genetic history of dogs is far from finished, the new data sheds light on more clues.

“I think it’s an important technical achievement to get more ancient dog genomes,” said Krishna Veeramah, a geneticist at Stony Brook University who has studied ancient dog evolution. He also claims that until now, we have only sequenced the nuclear DNA of three other breeds of ancient dog.

“While the study does not really address the ultimate origins of dogs from wolves (this will need older samples from Eurasia), it sheds new light on an important aspect of dog-human history,” he said.

Ultimately, the new data will add to our current archaeological and genetic research and continue painting a picture of the history of the world’s most iconic domestic animals.

The findings were published in Science.

Life on Earth evolved earlier than previously thought, study says

A new timescale of life on Earth suggests that it evolved much earlier than we thought.

Researchers from the University of Bristol have created a new timescale of life on Earth, which suggests that it evolved earlier than we previously thought. The new study combined fossil and genomic data to come to its surprising conclusion.

The fossil record on Earth is very fragmented, with a significant deterioration observed back in time towards the Archaen period that took place over 2.5 billion years ago. During this time, the Earth’s crust cooled enough to pave the way for the formation of continents and microbe lifeforms.

“There are few fossils from the Archaean and they generally cannot be unambiguously assigned to the lineages we are familiar with, like the blue-green algae or the salt-loving archaebacteria that colours salt-marshes pink all around the world,” said Holly Betts, lead author of the study.

“The problem with the early fossil record of life is that it is so limited and difficult to interpret—careful reanalysis of the some of the very oldest fossils has shown them to be crystals, not fossils at all,” she continued.

By combining genomic and fossil information, the team found that the Last Universal Common Ancestor (LUCA) of all cellular life forms existed nearly 4.5 billion years ago, which is earlier than the oldest known fossil evidence suggests.

“Our results indicate that two ‘primary’ lineages of life emerged from LUCA (the Eubacteria and the Archaebacteria), approximately one Billion years after LUCA,” said co-author and professor Davide Pisani.

“This result is testament to the power of genomic information, as it is impossible, based on the available fossil information, to discriminate between the oldest eubacterial and archaebacterial fossil remains,” he added.

The findings were published in Nature Ecology & Evolution.

Scientists suggest that winged reptiles existed before dinosaurs

A new winged reptile fossil predates dinosaur evolution by 65 million years.

Researchers just discovered a new species of pterosaur, which is the family of prehistoric flying reptiles that includes the pterodactyl. Interestingly, the specimen is approximately 210 million years old, which pre-dates its relatives by 65 million years.

The bones of the new species, named Caelestiventus hanseni, were preserved in desert oasis remains. They suggest that the species thrived on Earth prior to the evolution of dinosaurs.

The pterosaurs are the oldest flying vertebrates and a close relative of Dimorphodon. And since they were the first to evolve powered flight, their bird-like skeletons are often delicate and in a crushed state.

“Most of them are heavily distorted; literally like roadkill,” said lead author Brooks Britt, from Brigham Young University in Utah.

“The bones are so delicate, you can’t take them all the way out of the rock because they would just fall apart,” he added.

The team created a digital profile of the skull using a computed tomography (CT) scan and then printed a 3D model, which revealed a complex set of teeth.

“This one site we’ve pulled out 18,000 bones from an area the size of a good sized living room,” Britt said. “And there’s only one pterosaur.”

Although the specimen hadn’t reached adulthood, it had a wingspan of one-and-a-half meters.

“It was probably the biggest of its day,’ Britt said. “Among its peers, we have no evidence that any rival came close to that.”

The team plans to continue conducting research on the fossil in order to better understand what it ate and how it lived.

The findings were published in Nature Ecology & Evolution.

Human prehistoric ancestors mated with each other, study says

A new study suggests that our ancient human ancestors mated with each other more frequently than we thought.

A new study reveals an inter-species prehistoric human ancestor with a Denisovan father and Neanderthal mother. The unique lovechild was named Denisova and was at least 13 years old when she died of unknown causes.

“There was earlier evidence of interbreeding between different hominin, or early human, groups,” said Vivian Slon, lead author of the study. “But this is the first time that we have found a direct, first-generation offspring.”

The team analyzed the remains of a bone fragment discovered in 2012 by Russian archaeologists, which revealed chromosomes that were half Denisovan and half Neanderthal. Both of these early human species split apart approximately 400,000 to 500,000 years ago.

“I initially thought that they must have screwed up in the lab,” said senior author Svante Paabo.

Less than two dozen human genomes from before 40,000 years ago have been sequenced. Not only that, but the chances of discovering a half-and-half hybrid is already very small.

“The very fact that we found this individual of mixed Neanderthal and Denisovan origins suggests that they interbred much more often than we thought,” Slon said.

“They must have quite commonly had kids together, otherwise we wouldn’t have been this lucky,” Paablo agreed.

“Part of the story of these groups is that they may simply have been absorbed by modern populations,” he added. “The modern humans were more numerous, and the other species might have been incorporated.”

The study highlights the possibility that Denisovans and Neanderthals might have mated more if not for the fact that the former typically settled in Europe.

The findings were published in Nature.

Homo sapiens created ecological niche to break away from other hominins

A new study suggests that Homo sapiens are the last surviving hominin due to unique adaptations and environmental diversity.

A new review of palaeoenvironmental and archaeological data from the hominin dispersals in the Middle and Late Pleistocene suggests that Homo sapiens underwent unique adaptations and environments compared to previous hominins, which could be the reason that we are the last surviving hominin on the planet.

The study suggests that humans have been able to occupy such diverse environmental settings due to what is referred to as a new ecological niche called the “generalist specialist.”

“A traditional ecological dichotomy exists between ‘generalists’, who can make use of a variety of different resources and inhabit a variety of environmental conditions, and ‘specialists’, who have a limited diet and narrow environmental tolerance,” said Patrick Roberts, lead author of the paper.

“However, Homo sapiens furnish evidence for ‘specialist’ populations, such as mountain rainforest foragers or palaeoarctic mammoth hunters, existing within what is traditionally defined as a ‘generalist’ species,'” he added.

Not only that, but there is an increasing amount of evidence for hominin interbreeding, which the team suggests is a sign that researchers should begin to focus on the connection between fossils and their environment.

“While we often get excited by the discovery of new fossils or genomes, perhaps we need to think about the behavioural implications of these discoveries in more detail, and pay more attention to what these new finds tell us about new the passing of ecological thresholds,” said Brian Stewart, co-author of the study.

“As with other definitions of human origins, problems of preservation also make it difficult to pinpoint the origins of humans as an ecological pioneer,” Roberts concluded. “However, an ecological perspective on the origins and nature of our species potentially illuminates the unique path of Homo sapiens as it rapidly came to dominate the Earth’s diverse continents and environments.”

The findings were published in Nature Human Behavior.

Dinosaurs ate cleaner than we do, study says

Contrary to previous data, new research suggests that dinosaurs ate healthier than humans of the 21st century.

A recent study reveals that the vegetables eaten by herbivore dinosaurs approximately 150 million years ago were more nutritious than the ones that humans consume in the 21st century. The researchers examined nutritional value by growing similar foods in atmospheric conditions that mirrored those believed to have been present years ago.

Although early research suggested that the high-carbon dioxide atmospheres of the dinosaur age produced foods of low nutritional value, the new study found that their plants, such as ginkgo and horsetail, had significantly higher nutrient and energy levels than previously believed.

“The climate was very different in the Mesozoic era – when the huge brachiosaurus and diplodocus lived – with possibly much higher carbon dioxide levels,” said Fiona Gill at the University of Leeds, who led the research. “There has been the assumption that as plants grow faster and/or bigger under higher CO2 levels, their nutritional value decreases. Our results show this isn’t the case for all plant species.”

“The large body size of sauropods at that time would suggest they needed huge quantities of energy to sustain them,” she continued. “When the available food source has higher nutrient and energy levels it means less food needs to be consumed to provide sufficient energy, which in turn can affect population size and density.”

The data is not a complete picture of the dinosaur diet, but it sheds light on how dinosaurs ate and advances our understanding of how they survived.

“The exciting thing about our approach to growing plants in prehistoric atmospheric conditions is that it can be used to simulate other ecosystems and diets of other ancient megaherbivores, such as Miocene mammals – the ancestors of many modern mammals,” he further said.

The findings were published in Paleontology.