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The Earliest Sex Between Different Human Ancestors May Have Occurred 700,000 Years Ago – ScienceAlert

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Our evolutionary history is full of inter-species sex.

Different human ancestor species seem to have mingled and mated far more than anthropologists previously realised. Neanderthals interbred with modern humans. Homo sapiens had sex with Denisovans.

And 700,000 years ago, according to a new study, a population of ancient humans mated with a distinct, unknown population that had separated from other human species at least 1 million years prior.

“This continues the story that we’ve been seeing in studies throughout the past decade: There’s lots more interbreeding between lots of human populations than we were aware of ever before,” Alan Rodgers, an anthropologist and the lead author of the new study, told Business Insider.

“This discovery has pushed the time depth of those interbreedings much farther back.”

According to his team’s research, published today in the journal Science Advances, the newly discovered interbreeding event took place in Eurasia, and it represents the earliest known example of mating between different populations of ancient humans.

The analysis, which compared DNA from Neanderthals, Denisovans, and modern humans from Europe and Africa, lends further credence to the idea that the our ancestors’ genes (and our own) came from myriad sources.

The oldest episode of interbreeding in the anthropological record

When geneticists finished sequencing the Neanderthal genome in 2010, they realised that Neanderthals had interbred with modern humans between 40,000 and 60,000 years ago.

Then a 2018 study revealed that Denisovans – which disappeared about 50,000 years ago – passed on some of their genes to Homo sapiens.

But the interbreeding event that Rodgers and his colleagues found was far, far older. In that case, a group of humans who were ancestors of both Neanderthals and Denisovans (the study authors nicknamed them “neandersovans”) interbred with their predecessor species about 744,000 years ago.

Those predecessors, in turn, were part of a”superarchaic” group in Eurasia that was between 20,000 and 50,000 people in size.

A major implication of the study, then, is that human populations migrated from Africa to Eurasia three times during our long evolutionary history: once 1.9 million years ago, again 700,000 years ago, and then a final time 50,000 years ago.

The first of these waves involved the “superarchaics”. Then the neandersovans followed 700,000 years ago; they likely separated from the modern human lineage before they migrated north, the study suggests.

As that second wave of ancestors moved into Eurasia, the researchers wrote, they likely “interbred with indigenous Eurasians, largely replaced them, and separated into eastern and western subpopulations – Denisovans and Neanderthals.”

Then many hundreds of thousands of years later, modern humans left Africa, interbreeding with Neanderthals – and eventually Denisovans, too – as they spread through Eurasia.

“These same events unfolded once again around 50,000 years ago as modern humans expanded out of Africa and into Eurasia, largely replacing the Neanderthals and Denisovans,” the study authors wrote.

A population of ‘superarchaic humans’

Rodgers’ team’s discovery came after they compared publicly available modern human DNA with ancient DNA. The analysis revealed at least four watershed moments in which genetic material passed from one human species to another over the last 1 million years.

Three of those moments matched the results other studies had already found. But the oldest instance was a new find.

In addition to representing the oldest evidence of human interbreeding on record, the finding is also surprising because but the two populations that mated were far less closely related than other human groups previously known to have interbred.

Whereas modern humans and Neanderthals had been on separate branches of the evolutionary tree for about 750,000 years when they interbred, the newly discovered population and the “neandersovans” had been separated for more than 1 million years.

Several mysteries remain, however. Rodgers’ team isn’t sure what ancient species the “superarchaic” population belonged to.

All they know is that genetic evidence suggests the superarchaics separated from our human lineage about 2 million years ago, and that ancient humans were living in Eurasia at the time the species separation occurred.

“We’ve got fossil evidence of humans in Eurasia that dates back to 1.85 million years old,” Rogers said.

At least two groups of human species, or taxa, lived in Eurasia during the time the superarchaics broke off from our lineage. One, Homo erectus, was the first of our ancestors to walk upright. The other possible taxon was Homo erectus’ younger cousin, Homo antecessor, which inhabited modern-day Spain.

“Any of those taxa might be the superarchaics,” Rodgers said. “Or they might be some taxon we don’t know about yet.”

But regardless of which group the superarchaics belonged to, Rodgers said, the new evidence of interbreeding offers a glimpse into an ancient time period that researchers know very little about.

“We’re just shedding light on an interval on human evolutionary history that was previously completely dark,” he said.

This article was originally published by Business Insider.

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Move over, Stegosaurus, there’s a new armored dino in town – Popular Science

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Paleontologists in southern Argentina have recently discovered an adorable, five-foot-long armored dinosaur. The Jakapil kaniukura roamed the Earth during the hot and humid Cretaceous period roughly between 145.5 and 65.5 million years ago, and weighed 9 to 15 pounds–the size of the average domestic cat. 

The tiny dino’s fossilized remains were dug up during multiple digs over the over the past 10 years near a dam in Patagonia’s Río Negro province. The province is home to the La Buitrera palaeontological zone, a region well-known for the discovery of three complete southern raptors (Unenlagia) skeletons, herbivorous terrestrial crocodiles, the oldest found chelid turtles, and more.

Jakapil is part of the Thyreophoran dinosaur group that lived from the Jurassic period to the early Cretaceous period whose name means “shield bearer.” This feisty-looking group includes the bony backed, spiky tailed Stegosaurus and the tank-like Ankylosaurus. Like its prickly cousins, Jakapil had built in physical defenses, with rows of bony oval-shaped armor along its neck, back, and down to its tail.

[Related: This fossilized butthole gives us a rare window into dinosaur sex.]

“It bears unusual anatomical features showing that several traits traditionally associated with the heavy Cretaceous thyreophorans did not occur universally,” wrote the study’s authors, Facundo J. Riguetti, Sebastián Apesteguía, and Xabier Pereda-Suberbiola. “Jakapil also shows that early thyreophorans had a much broader geographic distribution than previously thought.”

The team published their findings in the journal Scientific Reports on August 11th. They first discovered Jakapil’s partial skeleton alongside 15 tooth fragments, which revealed that jakapil’s teeth were leaf-shaped like a modern-day iguana’s. 

According to lead paleontologist Sebastián Apesteguía, Jakapil marks the first-of-its-kind discovery of an armored dinosaur from the Cretaceous in South America. It also resembles a more primitive form of thyreophoran dinosaur that lived in the area significantly earlier. 

“Thyreophorans originated about 200 million years ago and rapidly evolved into various species distributed throughout the world,” Riguetti, first author of the work and a Conicet doctoral fellow at the Center for Biomedical, Environmental and Diagnostic Studies at Maimónides University said in a release. “However,of these early thyreophorans, the lineage represented by ‘Jakapil’ was the only one that lasted until at least 100 million years ago.”

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Full moon may hinder most anticipated meteor shower of the year – DiscoverWestman.com

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This weekend is the peak of Perseid’s meteor shower, one of the best-known and largest celestial events that can be seen from Earth.

Throughout the past couple of days, meteors have been visible to on-lookers and will get an even better view during the event’s peak on Friday night.

“Meteors are these tiny little pieces of space dust that crash into the earth and burn up, and when that happens we see them in the sky as a falling star or a shooting star,” says Scott Young, the Planetarium Astronomer at the Manitoba Museum. “The meteor is sort of the official name for those objects, and on any night you can probably see one or two of those if you’re lucky, but on certain nights of the year, the Earth goes through a big cloud of cosmic dust and when you get all that dust hitting the Earth all on the same night, you get lots of meteors. So we call that a meteor shower.”

Young also says that it won’t look as if thousands of stars are falling out of the sky, but rather it will be one star every minute instead of one a night.

“It always occurs every year around August 11-13, somewhere in that range because we’re going through the dust bunny left behind by a comet that crosses Earth’s orbit. Now, that doesn’t always mean that you will see all of those things hitting the Earth, and the timing might happen during the day for you. It might be cloudy, or like this year, close to the full moon. When the full moon is up, it makes it hard to see some of those fainter meteors that you would see.”

The best time to see any meteor shower is between midnight and dawn. According to Young, even with the bright light of the full moon on the same night as the peak time to see meteors, it is a strong enough shower that viewers will still be able to see shooting stars. 

“The official peak occurs after midnight, Friday night, so Saturday morning around 3:00 a.m. our time. But to be honest, it’s not a single-night event. It builds up over a previous couple of weeks and each night there’ll be more and more meteor showers until the peak and then after the peak, it fades away for a couple of weeks.”

The comet that causes the meteor shower is comet Swift–Tuttle, discovered by Lewis Swift and Horace Parnell Tuttle in 1862.

“Each meteor shower over the course of the year has its own source objects, most of them are comets and we know that when we get close to the comet’s orbit in our orbit, we’ll see this meteor shower. They’re actually named after the constellations in the sky where the meteors look like they’re coming from. When we’re looking at the sky, it seems that the meteors from the Perseid meteor shower will come from the constellation Perseus, which is rising in the northeastern part of the sky at this time of year. That doesn’t mean you have to know where Perseus is, the meteors can appear all over the sky.”

To get the best view of the meteor shower peak, Young suggests viewers go to a place where there are not a lot of lights and even “put your back towards any bright lights that are like the moon or city lights.” He also suggests putting the phone away, because the bright light will cause your eyes to need time to adjust to the dark sky and some of the dimmer shooting stars may be missed.

“This is one of those things where you have to unplug, disconnect and just lay out under the stars, relax and look up. it’s a great therapeutic way to connect with the sky.”

Normally on the peak day of the event, Young will go out with an all-sky camera and broadcast live on the Manitoba Museum’s Facebook and YouTube pages, but he says it always depends on the weather.

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Talk like you: Scientists discover why humans evolved to talk while other primates can’t – Euronews

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Why did humans evolve to talk, while monkeys were left to hoot, squeak and grunt to communicate?

The question has long puzzled scientists, who blamed our closest primate cousins’ inability to reproduce human speech sounds on their vocal anatomy.

Until now, researchers could not quite underpin what happened exactly during our evolution to make us able to speak while apes and monkeys can’t, given our vocal structures look almost identical to other primates.

Now, a new study published on Thursday in the journal Science claims to have the answer – and it’s not what anyone expected.

Analysing the phonal apparatus – the larynx – of 43 species of primates, a team of researchers based mainly in Japan found that all non-human primates – from orangutans to chimpanzees – had an additional feature in their throat that humans do not have.

Ability to speak and develop languages

While both humans and non-human primates produce sounds by forcing air through their larynges, causing folds of tissue to vibrate, monkeys and apes have an additional feature, a thin flap of tissue known as vocal membranes, or vocal lips.

Compared to apes and monkeys, humans were found to lack this anatomical vocal membrane – a small muscle just above the vocal cords – as well as balloon-like laryngeal structures called air sacs which apes and monkeys use to produce the loud calls and screams we’re not quite capable of.

According to the researchers, humans have lost this extra vocal tissue over time, somehow simplifying and stabilising the sounds coming out of our throat, and allowing us, in time, to develop the ability to speak – and eventually develop very complex sophisticated languages.

Monkeys and apes, on the other hand, maintained these vocal lips which don’t really allow them to control the inflection and register of their voice and produce stable, clear vocal fold vibrations.

“Paradoxically, the increased complexity of human spoken language thus followed simplification of our laryngeal anatomy,” says the study.

Communication through sign language

It’s unclear when humans lost these extra tissues still present in apes and monkeys and became able to speak, as the soft tissues in the larynx are not preserved in fossils, and researchers could only study living species.

We know that it must have happened sometime after the Homo Sapiens lineage split from the other primates, some 6-7 million years ago.

The fact that apes and monkeys haven’t developed the ability to speak like humans doesn’t mean that they are not able to clearly communicate with each other.

Though their vocal anatomy doesn’t allow them to form vowel sounds and proper words, non-human primates have a complex communication system based primarily on body language rather than oral sounds.

But monkeys and apes have also proven to be able to communicate with humans.

In the not-often-happy history of the interaction between non-human primates and humans, researchers have been able to teach apes and monkeys to communicate with people.

Koko the gorilla, for example, became famous for being able to use over 1,000 hand signs in sign language, while the bonobo Kanzi was reportedly able to communicate using a keyboard.

But when it comes to having a chat, monkeys and humans might never be able to share one.

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