Wolves survived the ice age as a single, global population

Image of a single wolf.

Enlarge / An Eastern Gray Wolf is a mix of Siberian ancestry and coyote DNA. (credit: Michael Cummings)

Man’s best friend was the first of many animals humans have domesticated. But there was no clear before-and-after moment where dogs were suddenly a distinct population of wolves. While some ancient skeletons are clearly dogs, there are a lot of ambiguous skeletons earlier than that. It’s possible to get a sense of what happened using the genomes of modern and ancient dogs. But this analysis depends heavily on what you think the wolf populations dogs were derived from look like.

Now, researchers have generated a much clearer picture of the last 100,000 years of wolf evolution. The picture it paints is a population that remained a single unit despite being spread across continents in the Arctic, with the population sporadically refreshed from a core centered in Siberia. Many breeds of dogs seem to have been derived from a population of East Asian wolves. But others seem to have also received significant input from a Middle East population—but it’s unclear whether that population was wolves or dogs.

Wolves around the north

The ability to sequence ancient DNA was essential to this new work, which involved obtaining DNA from 66 wolf skeletons that collectively span about 100,000 years of evolution, including most of the last ice age. Wolves are found in the Northern Hemisphere, and the skeletons used here tend to be closer to the Arctic (probably in part because DNA survives better in cooler climes). But they are widely distributed, with Europe, Asia, and North America represented. The researchers also included five ancient wolf genomes that others had analyzed, along with some genomes of modern wolves.

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#ancient-dna, #biology, #dogs, #evolution, #genomics, #science, #wolves

Heated Debate Persists over the Origins of Complex Cells

Were mitochondria a driving evolutionary force or just a late addition?

— Read more on ScientificAmerican.com

#biology, #evolution

Mutations thought to be harmless turn out to cause problems

The genetic code. Note that a lot of the amino acids (the outer layer, in grey) are encoded by several sets of three-base codes that share the first two letters.

Enlarge / The genetic code. Note that a lot of the amino acids (the outer layer, in grey) are encoded by several sets of three-base codes that share the first two letters. (credit: Wikipedia)

Mutations are the raw ingredient of evolution, providing variation that sometimes makes an organism more successful in its environment. But most mutations are expected to be neutral and have no impact on an organism’s fitness. These can be incredibly useful since these incidental changes help us track evolutionary relationships without worrying about selection for or against the mutation affecting its frequency. All of the genetic ancestry tests, for example, rely heavily on tracking the presence of these neutral mutations.

But this week, a paper provided evidence that a significant category of mutations isn’t as neutral as we thought they were. The big caveat is that the study was done in yeast, which is a weird organism in a couple of ways, so we’ll have to see if the results hold in others.

True neutral?

One of the reasons that most mutations are neutral is that most of our DNA doesn’t seem to be doing anything useful. Only a few percent of the human genome is composed of the portion of genes that encode proteins, and only some of the nearby DNA is involved in controlling the activity of those genes. Outside of those regions, mutations don’t do much, either because the DNA there has no function or because the function isn’t very sensitive to having a precise sequence of bases in the DNA.

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#biology, #evolution, #genetics, #science

Gut check: Fossil finds give us a history of life—and what it ate

Gut check: Fossil finds give us a history of life—and what it ate

Enlarge (credit: Cheung Chung-Tat)

It’s frustrating and gross, but we’ve all done it. We’ve all stepped in poop.

Most of us would like to forget the experience. But 33 million years ago, now-extinct life forms stepped in it, and fossilization has ensured that those events will not be forgotten.

For archeologists, what was once repellent is now an absolute marvel, as it offers insight into extinct animals and their environments that we may not otherwise obtain. Similarly, other byproducts of life we might find disgusting—regurgitated remnants of meals, internal organs and their contents—are important clues into creatures we only know about from the fossil record.

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#crocodilians, #evolution, #features, #paleontology, #pterosaurs, #science

What the simple mathematical abilities of animals can tell us about ourselves

What the simple mathematical abilities of animals can tell us about ourselves

Enlarge (credit: Aurich Lawson)

We often think of mathematical ability as being uniquely human, but in fact, scientists have found that many animal species—including lions, chimpanzees, birds, bees, ants, and fish—seem to possess at least a rudimentary counting ability or number sense. Crows can understand the concept of zero. And a study published in April found that both stingrays and cichlids can take this rudimentary “numerosity” to the next level, performing simple addition and subtraction for a small number of objects (in the range of 1 to 5).

The latter study’s conclusion doesn’t surprise cognitive psychologist Brian Butterworth, an emeritus professor at University College London and author of a new book, Can Fish Count? What Animals Reveal About our Uniquely Mathematical Minds.

“There are lots of animals that can do addition and subtraction,” Butterworth told Ars. “Bees can. Bees can represent zero as well. So it’s not surprising to me that stingrays and cichlids can do it.” His book explores how the ability to process mathematical information and extract numerical data from their environment is critical to an animal’s ability to survive and thrive. In fact, there might just be an innate understanding of math at its most basic level that was passed down the evolutionary chain from our most distant common ancestors.

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#animal-cognition, #animals, #biology, #books, #cognitive-neuroscience, #cognitive-psychology, #evolution, #gaming-culture, #mathematical-ability, #science

Ancient Giraffe Relative Was Evolution’s Headbutting Champion, Perhaps Besting Dinosaurs

Natural selection propels the giraffe family to absolute extremes—and it is not just about the absurdly long necks

— Read more on ScientificAmerican.com

#biology, #evolution

The (fossil) eyes have it: Evidence that an ancient owl hunted in daylight

The (fossil) eyes have it: Evidence that an ancient owl hunted in daylight

Enlarge (credit: IVPP)

An extraordinarily well-preserved fossil owl was described in PNAS this past March. Owls are not new to the fossil record; evidence of their existence has been found in scattered limbs and fragments from the Pleistocene to the Paleocene (approximately 11,700 years to 65 million years ago). What makes this fossil unique is not only the rare preservation of its near-complete articulated skeleton but that it provides the first evidence of diurnal behavior millions of years earlier than previously thought. 

In other words, this ancient owl didn’t stalk its prey under the cloak of darkness. Instead, the bird was active under the rays of the Miocene sun.

Seeing the light

Its eye socket was key to making this determination. Dr. Zhiheng Li is lead author on the paper and a vertebrate paleontologist who focuses on fossil birds at the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) in China. He explained in an email that the large bones around the eyes of birds (but not mammals) known as the scleral ossicles offer information about the size of the pupil they surround. In this case, the pupils of this fossil owl were small. And if the pupil is small, he wrote, it “means they can obtain good vision with a smaller eye opening.”

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#birds, #evolution, #fossils, #owls, #paleontology, #science

Two-Headed Worms Tell Us Something Fascinating About Evolution

Researchers looked back at more than 100 years of research, and they found a fascination with annelids with mixed up appendages was strong–and that research still has relevance today. 

— Read more on ScientificAmerican.com

#animals, #biology, #evolution

A Guide to the Different Omicron Subvariants

How to tell the different versions of SARS-CoV-2 apart, and how well vaccines protect against them

— Read more on ScientificAmerican.com

#biology, #epidemiology, #evolution, #health

Genetics goes to the dogs, finds there’s not much to breed behavior

Image of a white dog with a smile.

Enlarge / In the case of the samoyed, selection for physical characteristics produced a dog that sure looks happy. (credit: Zhao Hui)

Many dog breeds are purely about appearance—think poodles and the Pekingese. But plenty of other breeds are devoted to specific tasks, like racing greyhounds. For many of these tasks, physical appearance isn’t enough: behavior also matters. Things like herding by sheepdog breeds or fetching by various retrievers.

It’s not surprising that many people ascribe these behaviors—and a wide variety of other, less useful ones—to their dog’s breed and its underlying genetics. Now, a large team of US-based researchers has looked into whether this belief is accurate. And, with a few exceptions, they find that it’s not. With a huge panel of volunteer dog owners, they show that the genetics of dog behavior is built from lots of small, weak influences, and every breed seems to have some members that just don’t behave as we expect.

Dogs, meet Darwin

The work is based on a citizen science project called Darwin’s Ark. Participants were asked to give details about their dog, including whether it belonged to an established breed (either certified or inferred). They were also asked to fill out short surveys that collectively asked about 117 different behaviors. Overall, they obtained data on some 18,000 dogs, about half of them from purebreds.

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#biology, #dogs, #evolution, #genetics, #science

Pterosaurs May Have Had Brightly Colored Feathers, Exquisite Fossil Reveals

An amazingly well-preserved fossil suggests the common ancestor of dinosaurs and pterosaurs also had some type of feather or feather precursor

— Read more on ScientificAmerican.com

#biology, #evolution, #paleontology

Paul Sutter explores the origins of life, and DNA versus RNA

Produced and directed by Corey Eisenstein. Click here for transcript. (video link)

After spending three episodes looking to the heavens—first at dark matter, then Mars, then black holes—our intrepid host Paul Sutter now turns his gaze to a more terrestrial topic: Why are we here?

And I don’t mean in a Nietzschean sense (and if it’s Nietzschean discussions you want, Ars Deputy Editor Nate Anderson has you covered in his upcoming book on Nietzsche!)—Paul’s question is much more physical. Why are we here, specifically—we complex, multicellular sentient beings made of gobs and gobs of proteins and self-replicating DNA? Why is life a thing? How, billions of years ago, did Earth go from a planet devoid of life to a planet festooned with it?

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#ars-shopping, #ars-technica-videos, #bacteria, #dna, #edge-of-knowledge, #evolution, #feature, #features, #paul-sutter, #rna, #science

Social Animals Seek Power in Surprisingly Complex Ways

It’s not just physical combat—animals have a host of strategies for building clout

— Read more on ScientificAmerican.com

#animals, #biology, #evolution

Titanosaur nesting spot found in Brazil

Titanosaur nesting spot found in Brazil

Enlarge (credit: Júlia d’Oliveira)

They were the largest land creatures the Earth has ever known. But what survived millions of years of fossilization in one specific area of the Ponte Alta region of Brazil was not their massive bones, rather, it was their rare and relatively tiny eggs. And many of them! The first titanosaur nesting site in the country was recently announced in a paper published in Scientific Reports.

Sauropods, a group of long-necked herbivores, were a diverse type of dinosaur that lived from the Jurassic era through the Cretaceous, a period spanning from 201 million years to 66 million years ago. Titanosaurs were a clade of sauropod—a group with a common ancestor—that was the last of this lineage to exist on this planet in the Late Cretaceous. While their name justifiably implies an enormous size, not all of them were huge.

South America is well-known for its titanosaur fossils, particularly in Argentina, home to some of the world’s most spectacular titanosaur nesting sites and embryonic remains. Titanosaur eggshells and egg fragments are known in Uruguay, Peru, and Brazil, but a fossilized egg here and there doesn’t provide evidence of a nesting site. Several egg clutches, numerous eggs and egg fragments in more than one layer of sediment, does.

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#biology, #evolution, #fossils, #paleontology, #science, #titanosaurs

Big triceratops was healing a hole in its head

Full skeleton of a triceratops.

Enlarge / Meet Big John. (credit: Zoic Limited Liability Company)

It’s difficult to tell which feature of the triceratops is more striking: the two large horns that jut from its forehead or the large frill that extends out from the back of its skull. In the minds of many paleontologists, the two features appear to be related. Scars found in the bones supporting the frill also seem to suggest that the animals engaged in combat with their horns, much like modern animals such as moose—fights that regularly resulted in injuries.

But it’s difficult to rule out alternative explanations for some of the holes found in the fossil remains of frills. Some of the holes could have been a result of decay with age or damage after death. Now, an analysis of a triceratops skeleton known as “Big John” eliminates a couple of possibilities by showing that a hole punched through one of the bones of the frill seems to have started healing before the animal died.

Hole in one

The large frill at the back of a triceratops’ head is made from large, bony plates that are fused with the bones that do the things we normally associate with skulls, like protecting the brain. They were present in early species in this lineage that lacked pronounced horns and so are thought to have originally evolved for display purposes.

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#biology, #dinosaurs, #evolution, #paleontology, #science, #triceratops

Mysterious benefactor returns Charles Darwin’s missing notebooks after 20 years

Two notebooks belonging to Charles Darwin, one of which contains his iconic 1837 “Tree of Life” sketch, have been safely returned to Cambridge University Library, more than two decades after first being reported missing.

Twenty years ago, two small notebooks written by 19th-century naturalist Charles Darwin mysteriously disappeared from the archives of Cambridge University Library. One of the notebooks even contains Darwin’s iconic 1837 sketch of the so-called “Tree of Life.” After multiple searches and a public appeal, the notebooks have finally been returned by an anonymous person.

“My sense of relief at the notebooks’ safe return is profound and almost impossible to adequately express,” said Cambridge University Librarian Jessica Gardner in a statement. “Along with so many others all across the world, I was heartbroken to learn of their loss, and my joy at their return is immense. They may be tiny, just the size of postcards, but the notebooks’ impact on the history of science and their importance to our world-class collections here cannot be overstated.”

A page from Darwin's 1837 notebook showing the "Tree of Life" sketch.

A page from Darwin’s 1837 notebook showing the “Tree of Life” sketch. (credit: Stuart Roberts/Cambridge University Library)

Darwin famously set sail on the HMS Beagle on December 27, 1831, as the ship’s naturalist. The expedition’s purpose was to chart the coastline of South America, and Darwin’s job was to collect and record specimens as well as investigate local geography at the various landing sites. He dutifully recorded all his observations in his notebooks and shipped many of his finds back to England so other scientists could study them. Originally slated to last for two years, the voyage took nearly five years to complete.

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#charles-darwin, #evolution, #gaming-culture, #history-of-science, #science, #tree-of-life

Lost Genes Explain Vampire Bats’ Diet of Blood

To survive on nutrient-poor blood, less can sometimes be more

— Read more on ScientificAmerican.com

#animals, #biology, #evolution

Urban Evolution: How Species Adapt to Survive in Cities

Evolution in cities illuminates longstanding scientific questions and climate change futures

— Read more on ScientificAmerican.com

#biology, #evolution

Snakes’ and Lizards’ Slow and Steady Evolution Won the Race

A related lineage’s explosive growth leaves just one descendant today

— Read more on ScientificAmerican.com

#advances, #biology, #evolution

“Evolution can occur really, really rapidly”

Image of a fruit fly.

Enlarge / Don’t bother me, I’m busy evolving. (credit: Indrek Lainjärv / EyeEm)

When we think of evolution, we often think of slow, gradual changes made over millions of years. However, new research suggests that the process could be happening quite quickly, driving major changes over the course of a single year in response to seasonal changes.

The paper describing that research was released last week and studies evolution in fruit flies over around 10 generations, with each generation of flies spanning less than a dozen days. While fruit flies are notoriously short-lived, and the distance between their generations is tiny, evolution could be happening quicker than previously anticipated even in longer-lived organisms, according to Seth Rudman, assistant professor in the school of biological sciences at Washington State University and one of the authors of the paper.

“Over the last few decades there has been a growing appreciation that evolution can occur fairly rapidly,” he told Ars.

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#adaptation, #biology, #evolution, #flies, #fruit-flies, #insects, #science

Newly Discovered Saber-Tooth Predator Shows How Hypercarnivores Evolved

A well-preserved fossil introduces a new species that lived in what is now California around 42 million years ago

— Read more on ScientificAmerican.com

#biology, #evolution, #paleontology

Newly Discovered Saber-Toothed Predator Shows How Hypercarnivores Evolved

A well-preserved fossil introduces a new species that lived in what is now California around 42 million years ago

— Read more on ScientificAmerican.com

#biology, #evolution, #paleontology

The Devastating Loss of Grandparents among One Million COVID Dead

Grandparents are a majority of the pandemic’s death toll

— Read more on ScientificAmerican.com

#evolution, #health

Why covering anti-evolution laws has me worried about the future of vaccines

Why covering anti-evolution laws has me worried about the future of vaccines

Enlarge (credit: Aurich Lawson)

Prior to the pandemic, the opposition to vaccines was apolitical. The true believers were a small population and confined to the fringes of both major parties, with no significant representation in the political mainstream. But over the past year, political opposition to vaccine mandates has solidified, with a steady stream of bills introduced attempting to block various ways of encouraging or requiring COVID vaccinations.

This naturally led vaccine proponents to ask why these same lawmakers weren’t up in arms in the many decades that schools, the military, and other organizations required vaccines against things like the measles and polio. After all, pointing out logical inconsistencies like that makes for a powerful argument, right?

Be careful what you wish for. Vaccine mandate opponents have started trying to eliminate their logical inconsistency. Unfortunately, they’re doing it by trying to get rid of all mandates.

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#behavioral-science, #evolution, #science, #social-science, #vaccines

Rockshelter Discoveries Show Neandertals Were a Lot like Us

Our much maligned cousins made sophisticated ornaments and probably had language

— Read more on ScientificAmerican.com

#biology, #evolution, #features

A new database reveals how much humans are messing with evolution

A new database reveals how much humans are messing with evolution

Enlarge (credit: Natalie Fobes | Getty Images)

Charles Darwin thought of evolution as an incremental process, like the patient creep of glaciers or the march of continental plates. “We see nothing of these slow changes in progress until the hand of time has marked the long lapse of ages,” he wrote in On the Origin of Species, his famous 1859 treatise on natural selection.

But by the 1970s, scientists were finding evidence that Darwin might be wrong—at least about the timescale. Peppered moths living in industrial areas of Britain were getting darker, better for blending in against the soot-blackened buildings and avoiding predation from the air. House sparrows—introduced to North America from Europe—were changing size and color according to the climate of their new homes. Tufted hairgrass growing around electricity pylons was developing a tolerance for zinc (which is used as a coating for pylons and can be toxic to plants).

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#climate-change, #evolution, #habitats, #science

A Strange Creature Discards Genes to Make a Better Heart

The sea squirt relative demonstrates that sometimes less is more: losing genes can be adaptive

— Read more on ScientificAmerican.com

#biology, #evolution

Junk DNA Deforms Salamander Bodies

Yet the unfit creatures survive, challenging our long-held view of evolution

— Read more on ScientificAmerican.com

#animals, #biology, #evolution, #features

Did eating meat really make us human?

Did eating meat really make us human?

Enlarge (credit: Kryssia Campos | Getty Images)

Twenty-four years ago, Briana Pobiner reached into the north Kenyan soil and put her hands on bones that had last been touched 1.5 million years ago. Pobiner, a paleoanthropologist, was digging up ancient animal bones and searching for cuts and dents, signs that they had been butchered by our early ancestors trying to get at the fatty, calorie-rich bone marrow hidden within. “You are reaching through a window in time,” says Pobiner, who is now at the Smithsonian Institution in Washington, DC. “The creature who butchered this animal is not quite like you, but you’re uncovering this direct evidence of behavior. It’s really exciting.”

That moment sparked Pobiner’s lasting interest in how the diets of our ancestors shaped their evolution and eventually the emergence of our own species, Homo sapiens. Meat, in particular, seems to have played a crucial role. Our more distant ancestors mostly ate plants and had short legs and small brains similar in size to a chimpanzee’s. But around 2 million years ago, a new species emerged with decidedly humanlike features. Homo erectus had a larger brain, smaller gut, and limbs proportioned similarly to those of modern humans. And fossils from around the same time, like those excavated by Pobiner in Kenya, show that someone was butchering animals to separate lean meat from the bone and dig out the marrow. For decades, paleontologists have theorized that the evolution of humanlike features and meat eating are strongly connected.

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#anthropology, #archaeology, #carnivore, #evolution, #homo-erectus, #homo-sapiens, #meat-eating, #science

Fossils Reveal When Animals Started Making Noise

For billions of years Earth was quiet. Then life got loud

— Read more on ScientificAmerican.com

#animals, #biology, #evolution, #features

For mammals, eating other animals can increase cancer risk

These rodents seemingly manage to avoid developing cancer.

Enlarge / These rodents seemingly manage to avoid developing cancer. (credit: Jason Hollinger / Wikimedia Commons)

Cancer is a sad fact of life, as nearly 40 percent of people are diagnosed with it at some point in their lives. But humans aren’t alone in this. Many different species can also develop the disease—some more often than others. By studying these species and their habits and natural defenses (or lack thereof), we can learn new ways to combat the disease.

New research that involves a comprehensive survey of cancer shows that many mammals can indeed get cancer. To gain insight into this, the team looked at records for 110,148 animals from 191 species that died in zoos. The data came from Species360, an international non-profit that collects and unifies this kind of data from zoos across the world, according to Orsolya Vincze, a research fellow at the Centre for Ecological Research in Hungary and one of the paper’s authors.

Using the data gathered by the organization, the research team could “collect information on what the animals died of,” she told Ars.

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#cancer, #ecology, #evolution, #mammals, #petos-paradox, #science

How Did Neanderthals and Other Ancient Humans Learn to Count?

Archaeological finds suggest that people developed numbers tens of thousands of years ago. Scholars are now exploring the first detailed hypotheses about this life-changing invention

— Read more on ScientificAmerican.com

#biology, #evolution, #features

Fish Do the Wave to Ward Off Predatory Birds

The synchronized dances of sulfur mollies is not only mesmerizing to watch, but also confusing to predators

— Read more on ScientificAmerican.com

#animals, #biology, #evolution

New Clues about the Origins of Biological Intelligence

A common solution is emerging in two different fields: developmental biology and neuroscience

— Read more on ScientificAmerican.com

#biology, #evolution

Humans Are Doomed to Go Extinct

Habitat degradation, low genetic variation and declining fertility are setting Homo sapiens up for collapse 

— Read more on ScientificAmerican.com

#biology, #evolution, #genetics, #reproduction

Redo of a Famous Experiment on the Origins of Life Reveals Critical Detail Missed for Decades

The Miller-Urey experiment showed that the conditions of early Earth could be simulated in a glass flask. New research finds the flask itself played an under appreciated, though outsized role.

— Read more on ScientificAmerican.com

#biology, #evolution

The Surprising Secret of Snakes’ Venomous Bites

Fangs evolved over and over because of this groovy process

— Read more on ScientificAmerican.com

#advances, #animals, #biology, #evolution

Physical Activity Could Be an Evolutionary Adaptation for Grandparenting

It may force energy shifts to repair and maintenance, which could slow aging and make us more available to care for younger generations

— Read more on ScientificAmerican.com

#biology, #evolution

Sponge Cells Hint at Origins of Nervous System

Synapse genes help cells to communicate in sponge’s digestive chambers

— Read more on ScientificAmerican.com

#biology, #evolution

Poaching drove the evolution of tusk-free elephants

Image of three elephants

Enlarge (credit: Bisakha Datta / Getty Images)

In the wake of severe poaching problems, some wildlife authorities have resorted to removing the horns of rhinos in order to eliminate the reason they’re poached in the first place. It turns out that, in the wake of a severe poaching event, evolution came up with a similar solution.

A 15-year-long civil war in Mozambique set off a burst of poaching that ultimately killed 90 percent of a national park’s elephant population. In the wake of that, tuskless elephants were seen in the park. That’s surprising, since tusks play an important role in elephants’ foraging and defenses against predators. Now, researchers have revealed that the lack of tusks was the result of genetic changes and have even identified the genes that were likely behind it.

A change of face

Over the course of the Mozambican Civil War, the population of elephants in Gorongosa National Park dropped from 2,542 to just 242. But the remaining population contained a significant number of elephants that lacked tusks. Models of the population and rates of tusklessness suggest that animals without them were roughly five times more likely to survive than their fellows with tusks.

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#biology, #elephants, #evolution, #genetics, #genomics, #poaching, #science

Trapped in amber: Fossilized dinosaur-era crab bridges evolutionary gap

Trapped in amber: Fossilized dinosaur-era crab bridges evolutionary gap

Enlarge

Once upon a time, during the Cretaceous period, a tiny crab wandered out of the water onto land and somehow got trapped in amber, which preserved it for 100 million years. At least that’s what a team of scientists hypothesize might have happened in a new paper announcing their discovery of the oldest known modern-looking crab yet found in the fossil record. The paper was published in the journal Science Advances.

This new type of “true crab” (aka a brachyuran) measures just five millimeters in leg span and has been dubbed Cretapsara athanata. The name is meant to honor the period in which the crab lived and Apsara, a South and Southeast Asian spirit of the clouds and waters. “Athanatos” means “immortal,” a sly reference to the fossilized crab being frozen in time.

It’s rare to find nonmarine crab fossils from this era trapped in amber; most such amber fossils are those of insects. And the previously discovered crabby fossils are incomplete, usually consisting of pieces of claws. This latest find is so complete that it doesn’t seem to be missing even a single hair. The find is of particular interest because it pushes back the time frame for when nonmarine crabs crawled onto land by 25 to 50 million years—consistent with long-standing theories on the genetic history of crabs—and offers new insight into the so-called Cretaceous Crab Revolution, when crabs diversified worldwide.

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#animals, #crabs, #cretaceous, #evolution, #fossils, #micro-ct-scanning, #paleontology, #science, #transitional-fossils

How a mass extinction resulted in the rise of the snakes

Image of a snake on a branch.

Enlarge / Today’s diverse snake populations may trace back to a single ancestral species that survived the dinosaur-killing mass extinction. (credit: Alan Tunnicliffe Photography / Getty Images)

The doom of the dinosaurs was good news for snakes. According to new research, snake biodiversity began increasing shortly after the Cretaceous–Paleogene mass extinction—you know, the one brought about by a huge asteroid impact 66 million years ago. The asteroid caused around 75 percent of all species, and all of the non-avian dinosaurs, to go extinct.

But the impact gave primordial snake species opportunity and space to flourish, and they did. Currently, there are around 4,000 species of the elongated, legless reptiles. To study this evolutionary change, a team of researchers examined the diets of existing snake species to get a glimpse into the past. “After the K–Pg extinction, [snakes] just underwent this massive ecological explosion,” Michael Grundler, one of the paper’s authors and a post-doc researcher at the University of California Los Angeles, told Ars.

Rare fossils

As it turns out, snake fossils are hard to come by. It’s rare to find any great snake because their bodies are loosely articulated and can fragment quickly. “They’re really rare in the fossil record. And when we do see them in the fossil record, it’s usually just a bit of vertebrae, often not really a skull, so we can’t get a sense of their ecology,” Grundler said. “It’s not something like a big mammal or a big dinosaur that has four limbs and the bones are pretty robust. With snakes, you have all these fragile vertebrae… their skull is pretty loosely articulated as well.”

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#biodiversity, #evolution, #mass-extinction, #science, #snakes

Night Flights Are No Sweat for Tropical Bees

New research uses night vision to see how nocturnal bees navigate the dark.

— Read more on ScientificAmerican.com

#animals, #biology, #evolution

Meet the Bat Woman and Bat Man of India

They sealed their love with dead bats. Now these researchers are on a mission to save India’s endangered chiropteran species together.

— Read more on ScientificAmerican.com

#biology, #evolution

Kids’ Fossilized Handprints May Be Some of the World’s Oldest Art

Ice Age impressions in limestone show that human ancestors inhabited the area

— Read more on ScientificAmerican.com

#biology, #evolution, #paleontology

During a Rodent Quadrathlon, Researchers Learn That Ground Squirrels Have Personalities

The rodents’ personalities may help them to secure territory and avoid prey.

— Read more on ScientificAmerican.com

#biology, #evolution

Recent Ebola outbreak emerged from someone infected 5 years earlier

Image of two men in protective garments and goggles.

Enlarge / Health care workers don protective equipment before working with Ebola patients. (credit: Bloomberg / Getty Images)

A large international research group released a paper today suggesting that Ebola viruses can emerge from five years of dormancy to trigger a new outbreak of infections. While this isn’t the first instance in which Ebola re-emerged from a previously infected individual, the new results extend the timeframe of risk substantially.

At present, we have little idea how and where the virus persists in the human body. But there are now tens of thousands of people who have survived previous infections, so it’s an area where more research is urgently needed.

A re-outbreak

The African nation of Guinea experienced a small Ebola outbreak that started in January of 2021 when a nurse fell ill. Due to a misdiagnosis, she was not immediately isolated, allowing the virus to spread. Fortunately, a major outbreak that occurred in the same region from 2013 to 2016 resulted in the local health authorities obtaining sophisticated diagnostic equipment, including the real-time RT-PCR machines that are used for COVID-19 testing. This ultimately allowed the authorities to determine that Ebola was the cause of her illness, identify 15 additional cases, and take measures that brought the outbreak to a halt. In all, 12 of the 16 infected died.

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#ebola, #evolution, #genomics, #medicine, #public-health, #science, #virology

Recent Ebola outbreak emerged from someone infected 5 years earlier

Image of two men in protective garments and goggles.

Enlarge / Health care workers don protective equipment before working with Ebola patients. (credit: Bloomberg / Getty Images)

A large international research group released a paper today suggesting that Ebola viruses can emerge from five years of dormancy to trigger a new outbreak of infections. While this isn’t the first instance in which Ebola re-emerged from a previously infected individual, the new results extend the timeframe of risk substantially.

At present, we have little idea how and where the virus persists in the human body. But there are now tens of thousands of people who have survived previous infections, so it’s an area where more research is urgently needed.

A re-outbreak

The African nation of Guinea experienced a small Ebola outbreak that started in January of 2021 when a nurse fell ill. Due to a misdiagnosis, she was not immediately isolated, allowing the virus to spread. Fortunately, a major outbreak that occurred in the same region from 2013 to 2016 resulted in the local health authorities obtaining sophisticated diagnostic equipment, including the real-time RT-PCR machines that are used for COVID-19 testing. This ultimately allowed the authorities to determine that Ebola was the cause of her illness, identify 15 additional cases, and take measures that brought the outbreak to a halt. In all, 12 of the 16 infected died.

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#ebola, #evolution, #genomics, #medicine, #public-health, #science, #virology

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