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Who are the first ancestors of present-day fish? – Science Daily

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What is the origin of the ancestors of present-day fish? What species evolved from them? A 50-year-old scientific controversy revolved around the question of which group, the “bony-tongues” or the “eels,” was the oldest. A study by INRAE, the CNRS, the Pasteur Institute, Inserm and the Muséum National d’Histoire Naturelle, has just put an end to the debate by showing through genomic analysis that these fishes are in fact one and the same group, given the rather peculiar name of “Eloposteoglossocephala.” These results, published in Science, shed new light on the evolutionary history of fish.

Understanding the evolutionary history of species through their relatedness is an essential issue and regularly the subject of scientific controversy. One of them concerns the position, in the tree of life, of the three oldest groups of teleost fishes, which appeared towards the end of the Jurassic period (from 201.3 to 145 million years ago) and which include most of our present-day fishes. These three groups consist of the “bony-tongues,” the “eels” and a group that unites all other species of teleost fishes. Early classifications in the 1970s, based solely on anatomical criteria, had classified the “bony-tongues” as the oldest group. Modern classification approaches, however, based on the use of DNA sequences to reconstruct the evolutionary history of life, placed the “eels” as the oldest group. Ever since, controversy has ensued.

What if both hypotheses were wrong?

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To investigate this question, scientists sequenced the genomes of several species in the “eel” group, including the European eel and the giant moray eel. They analysed the DNA sequences to gain insight into the structure and organisation of the genes within the genome. They were thus able to reconstruct, in a very reliable way, the relationships between the different teleost fishes, which led to an end of the controversy without winners or losers: neither hypothesis was valid!

Surprisingly, scientists have discovered that the two groups of “eels” and “bony-tongues” are in fact one and the same in terms of evolutionary history. The researchers have named this group “Eloposteoglossocephala.” These results put an end to more than fifty years of controversy about the evolutionary history of the main branches of the teleost fish tree of life. They shed new light on the evolutionary history of fishes and the understanding of evolutionary processes.

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Ice Age Squirrel Found in Canada! » Expat Guide Turkey – Expat Guide Turkey

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The remains of an Ice Age squirrel that was mummified to death during hibernation some 30,000 years ago have been found in Canada.

The 30,000-year-old animal found in the Klondike goldfields in 2018 will soon be on display in Whitehorse, Northern Canada.

Yukon paleontologists this week unveiled another unusual find from the gold fields near Dawson City: an Arctic squirrel that curled up and mummified as if it died during hibernation during the Ice Age.

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A Squirrel Mummy Found by Yukon Paleontologists at the Gold Field near Dawson City

The Ice Age squirrel was actually found a few years ago, but its announcement is now being made as the government is preparing the dead rodent for display at the Yukon in Whitehorse.

At first glance, this mummified animal looks like nothing more than a dried up pile of brown fur and skin.

Intact Bone Structure Detected Inside the Remains

Yukon government paleontologist Grant Zazula says, “It’s hardly recognizable until you see the tiny hands and claws, a little tail, and then the ears.” says.

“I’m always examining bones and these are very exciting. But when you see a perfectly preserved animal, especially if it’s 30,000 years old and you can see its face, its skin, its fur, it’s really special.”

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Apr 1: Tyrannosaur lips, bald eagles dine on beef, saving the orbital environment and more… – CBC.ca

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Quirks and Quarks54:02Tyrannosaur lips, bald eagles dine on beef, saving the orbital environment, how your fingerprints are built and how humans run on electricity


On this week’s episode of Quirks & Quarks with Bob McDonald:

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Tyrannosaurus rex had lips covering its terrifying teeth

Quirks and Quarks8:33Tyrannosaurus rex had lips covering its terrifying teeth

Many depictions of the iconic Tyrannosaurus rex show the dinosaur’s huge teeth as constantly exposed in a crocodilian smile. But a new study published in the journal Science concludes that theropod dinosaurs like the T. rex likely had scaly, lizard-like lips that covered their teeth completely when the dinosaur’s mouth was closed. Canadian paleontologist Dr. Thomas Cullen, a professor at Auburn University, and his co-authors analyzed wear patterns on tooth enamel of the dinosaurs, as well as jaw sizes, and compared them to modern-day animals. He said the T. rex mouth would have likely been most similar to that of a Komodo dragon.

Scientists and artists have developed two principal models of predatory dinosaur facial appearances: crocodylian-like lipless jaws or a lizard-like lipped mouth. New data suggests that the latter model, lizard-like lips, applies to most, or all, predatory dinosaur species. (Mark P. Witton)

Eagles are eating cows instead of salmon – and farmers are happy

Quirks and Quarks7:59Eagles are eating cows instead of salmon – and farmers are happy

In the Pacific Northwest of the U.S., bald eagles, which have historically fed on the carcasses of spawning chum salmon, have run short of their traditional food due to climate change and other factors. But a new study in the journal Ecosphere by Ethan Duvall, a PhD student in ecology at Cornell University, indicates the eagles have moved inland and are now scavenging cattle who have died on dairy farms. Farmers, it turns out, are happy with this, as it solves a troubling disposal problem, and because the eagles also displace rodents and other birds that do harm to the farms.

A bald eagle in flight against clouds in the blue sky
Bald eagles have shifted their diet from chum salmon carcasses to the carcasses of dairy cows in the northwestern U.S. (NICK BALACHANOFFF)

Inspired by the High Seas treaty, scientists are calling for the protection of space

Quirks and Quarks7:47Inspired by the High Seas treaty, scientists are calling for the protection of space

In early March, nearly 200 United Nations member countries agreed to the first-ever treaty to protect the world’s oceans. Imogen Napper, a marine biologist at the University of Plymouth in England, and a group of colleagues are calling for a similar legally binding treaty to protect the Earth’s orbit from exploitation by the ever-growing global space industry. Their concerns were put forward in a letter in the journal Science.

A woman looks up into a starry sky with a beam of light coming from her headband light
Marine biologist Imogen Napper has turned her attention from ocean plastic pollution to protecting the Earth’s orbit from space debris. (Eleanor Burfit)

Arches, loops and whorls — how your unique fingerprints are made

Quirks and Quarks7:40Arches, loops and whorls — how your unique fingerprints are made

There are eight billion people in the world, each with a unique pattern of ridges on our fingertips. Now, scientists have discovered that the process by which these intricate and complex patterns arise is similar to how animals get their spots or stripes. Duelling genetic and chemical signals during fetal development give rise to changes in the ridges and spaces between them that cover our fingertips. Denis Headon, a geneticist from the University of Edinburgh, traced how this interplay results in the complex whorls, loops and arches that make up our fingerprints. His research was published in the journal Cell.

A computer monitor on a black desk in an ambiently lit room has a giant fingerprint blown up on it taking up the entire screen.
A fingerprint is enlarged for examination at the US Homeland Security Investigation Forensic Laboratory in Tyson Corner, Virginia. A new study describes how our fingerprints get their unique patterns. (Paul J. Richards/AFP/Getty Images)

Humans are fueled by food — but we run on electricity

Quirks and Quarks19:31Humans are fueled by food — but we run on electricity

Every living cell works as a battery, with the ability to respond to and send out electrical signals. Science and technology journalist, Sally Adee, became fascinated with this realization after participating in an experiment in which a gentle electrical current, delivered to her brain, gave her the abilities of an expert sharpshooter. Bob McDonald speaks with her about her new book, We Are Electric: Inside the 200-Year Hunt for Our Body’s Bioelectric Code, and What the Future Holds. In it, she explores how much our biology — from our bodies’ ability to heal to the higher order processes of human thought — works through electricity.

Someone's hand can be seen holding a multitude of colourful wires emanating from the electrodes in a cap that he's wearing as he sits inside a makeshift cockpit.
A man holds electrodes set up on the head of Swiss scientist-adventurer and pilot Bertrand Piccard that will monitor his electrical brain waves prior to a non-stop 72 hours simulation test flight in 2013. (Fabrice Coffrini/AFP/Getty Images)

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Meet the Canadian astronauts up for a seat on the Artemis II mission to the moon

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This Sunday, NASA and the Canadian Space Agency (CSA) will announce the four astronauts that will be blasting off to fly around the moon for the Artemis II mission, one of whom will be a Canadian astronaut.

The Artemis II mission will be the first crewed mission to orbit the moon in half a century, and the inclusion of a Canadian astronaut on the mission will make Canada the second country to have an astronaut fly around the moon.

In November 2024, NASA’s Kennedy Space Center in Florida will launch the four astronauts into space for the Artemis II mission. They will pilot the Orion spacecraft around the Earth and then around the moon before returning home.

It’s the second step of a project that started last year with the unmanned Artemis I mission. The Artemis missions help to test the launch system and the spacecraft itself. The end goal is for scientists to construct a Lunar Gateway at the moon — a space station that could serve as a jumping off point for further deep space exploration.

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A trailer for the crew announcement was posted by NASA on Wednesday.

There are currently four active Canadian astronauts, but we won’t know until Sunday who will be the first Canadian astronaut to fly around the moon.

THE CANDIDATES

Joshua Kutryk

Kutryk was born in Fort Saskatchewan, Alberta and grew up on a cattle farm in eastern Alberta. He is a member of the Canadian Armed Forces, and has been deployed in Libya and Afghanistan in the past.

He worked as an experimental test pilot and fighter pilot in Cold Lake, Alberta before he was recruited by the CSA. He worked on numerous test flight projects as well as on improving the safety of fighter jets such as the CF-18.

Kutryk made it to the top 16 candidates for the CSA in 2009, but wasn’t selected until CSA’s 2017 recruitment campaign.

He obtained the official title of astronaut in January 2020.

Jennifer Sidey-Gibbons

Sidey-Gibbons comes from Calgary, Alberta, and first worked with the CSA while studying mechanical engineering at McGill University, where she conducted research on flame propagation in microgravity in collaboration with the agency.

Before joining CSA, she lived and worked in the U.K. as an assistant professor in the Department of Engineering at the University of Cambridge. Her research there focused on how to develop low-emission combusted for gas turbine engines.

She was selected by the CSA in 2017 as a recruit along with Kutryk, and obtained the official title of astronaut in January 2020.

Jeremy Hansen

Hansen was born in London, Ontario and spent his childhood first on a farm near Ailsa Craig, Ontario, and then Ingersoll, Ontario. He is married with three children.

By age 17, he had already obtained glider and private pilot licences through the Air Cadet Program. He is a member of the Canadian Armed Forces and served as a CF-18 fighter pilot before becoming an astronaut.

Hansen graduated as an astronaut in 2011, after being selected as one of two recruits for the CSA in 2009. He currently represents the CSA at NASA and works at the Mission Control Center, serving as the point of connection between the ground and the International Space Station (ISS). He also helps to train astronauts at NASA, the first Canadian to do so.

David Saint-Jacques

Saint-Jacques grew up in Saint-Lambert, Quebec, near Montreal, and is married with three children.

Before joining the CSA, he worked as a medical doctor in Puvirnituq, Nunavik, an Inuit community in northern Quebec. He also works as an adjunct professor of family medicine at McGill University. As a biomedical engineer, he has worked in France and Hungary, and helped to develop optics systems for telescopes and arrays used at observatories in Japan, Hawaii and the Canary Islands.

He was selected as a recruit in 2009 by the CSA and graduated in 2011 from the NASA astronaut program. He has since worked with the Robotics Branch of the NASA Astronaut Office, as a support astronaut for various ISS missions and as the mission control radio operator for a number of resupply missions for the ISS.

In December 2018, Saint-Jacques flew to the ISS to complete a 204-day mission, which is the longest mission any Canadian astronaut has carried out in space to date. During this time, he became the fourth CSA astronaut to conduct a spacewalk and the first CSA astronaut to catch a visiting spacecraft using the Canadarm2.

 

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