Oxygen, I’m sure you’d agree, is pretty important for life on Earth. We breathe it in, our cells survive on it and without it, we’re pretty much doomed. Basically all multicellular life on Earth evolved to utilize oxygen over millions of years.
But take a deep breath because we need to talk about Henneguya salminicola, a tiny parasite containing less than 10 cells that lives within the muscle tissue of salmon. The alien-tadpole-looking parasite does not busy itself with such trifling matters as breathing oxygen. Nope, it seems H. salminicola is the first multicellular animal we’ve found that survives without the stuff.
“Aerobic respiration was thought to be ubiquitous in animals, but now we confirmed that this is not the case,” said Dorothee Huchon, a zoologist at Tel Aviv University in Israel, in a press release.
Huchon and a team of international researchers examined and sequenced all of H. salminicola’s genes in their study, published in the journal Proceedings of the National Academy of Sciences on Monday. They found the parasite, which is closely related to jellyfish, lacks the DNA machinery necessary to “breathe” — it doesn’t have a mitochondria. The mitochondria is often called the “powerhouse” of the cell, because it uses oxygen to make energy. It’s like a little factory inside (almost) all cells and DNA sleuths can find its genes during sequencing.
The discovery came as something of an accident for the team, who were probing the genome of the species. When they went searching for the mitochondrial genes, they came up empty-handed.
“Our discovery shows that evolution can go in strange directions,” Huchon said. “Aerobic respiration is a major source of energy, and yet we found an animal that gave up this critical pathway.”
Some single-celled lifeforms have evolved the ability to survive without oxygen and do not possess mitochondria, either. Plenty of bacteria and protozoans can exist without oxygen at all, like those at the bottom of the ocean near hydrothermal vents and some human pathogens which live inside the body. Instead of oxygen, they get their energy from fermentation or use other molecules like mercury or iron.
But how H. salminicola generates energy is still unclear. Huchon suggests it could draw oxygen from the cells in salmon or it could have evolved similar methods to unicellular organisms scientists have documented in the past.
NASA’s Hubble Space Telescope captured two festive-looking nebulas – Tech Explorist
The image shows NGC 248, about 60 light-years long and 20 light-years wide. They are two nebulas, situated to appear as one. The nebulas, together, are called NGC 248.
Initially discovered in 1834 by the astronomer Sir John Herschel, NGC 248 resides in the Small Magellanic Cloud, located approximately 200,000 light-years away in the southern constellation Tucana.
Small Magellanic Cloud is a dwarf galaxy that is a satellite of our Milky Way galaxy. The image is part of a study called Small Magellanic Cloud Investigation of Dust and Gas Evolution (SMIDGE).
The dwarf satellite galaxy contains several brilliant hydrogen nebulas, including NGC 248. Intense radiation from the brilliant central stars is heating hydrogen in each nebula, causing them to glow red.
The study’s principal investigator, Dr. Karin Sandstrom of the University of California, San Diego, said, “The Small Magellanic Cloud has between a fifth and a tenth of the amount of heavy elements that the Milky Way does. Because it is so close, astronomers can study its dust in great detail and learn about what dust was like earlier in the history of the universe.”
“It is important for understanding the history of our galaxy, too. Most of the star formation happened earlier in the universe, at a time when there was a much lower percentage of heavy elements than there is now. Dust is a critical part of how a galaxy works, how it forms stars.”
The image is part of a study called Small Magellanic Cloud Investigation of Dust and Gas Evolution (SMIDGE). The data used in this image were taken with Hubble’s Advanced Camera for Surveys in September 2015.
When To See An ‘Earth-Grazer’ This Weekend: Don’t Write-Off The Perseid Meteor Shower, Says Expert – Forbes
If you’ve ever laid down a blanket or set up a lawn chair to watch a meteor shower there’s a good chance it was to watch the Perseids.
Due to peak at 01:00 UT on Saturday, August 13, 2022, normal advice would be to be outside at that time (in Europe) or just as soon as its gets dark on Friday, August 12 (North America).
As I’ve already reported, this year the Perseids coincides with a full Moon, so all but the brightest meteors and “fireballs” (larger, brighter meteors) will be visible. So from the 50-75-or-so “shooting stars” you might normally see during the peak of the Perseids only a few—albeit bright—meteors will be visible.
It’s almost not worth the bother, I said, advising you to go watch this instead next weekend.
However, there is another opinion. In an article published on the American Meteor Society’s website, fireball coordinator Robert Lunsford says that despite the bright full Moon visible meteor rates during the peak of the Perseid meteor shower will be better than 95% of all other nights this year.
When to see the Perseid meteor shower
“Most of the Perseid meteors are faint and bright moonlight will make it difficult to view,” he writes. “Despite the glare of moonlight, the Perseids produce many bright meteors that can still be easily seen despite the bright moonlight.”
He also advises two great times to watch for shooting stars—just after sunset on Friday, August 12 and just before dawn on Saturday, August 13.
Perseids: ‘Earth-grazers’ just after sunset
You’ll need patience, but to see an “Earth-grazer” is unforgettable.
Just after sunset is actually thee worst time in terms of numbers of shooting stars you might see, but the few that do come your way this time of night are special.” The reason is that they just skim the upper regions of the atmosphere and will last much longer than Perseids seen during the morning hours,” writes Lunsford. “Most of these “earth-grazing” Perseids will be seen low in the east or west, traveling north to south.”
Perseids: ‘shooting stars’ before dawn
The activity from the Perseid meteor shower will peak where you are as the radiant—the constellation of Perseus—rises higher into the night sky. “Theoretically, the best time to watch the Perseids is just before the break of dawn when the radiant lies highest in a dark sky,” writes Lunsford. That’s about 04:00 local time, though he also reveals that experienced observers often say the hour between 03:00 and 04:00 is usually the best.
Perseids: ‘shooting stars’ in a moonless sky
If you want to look for Perseids in a dark, moonless sky then you’re mostly out of luck this year. By the time the full Moon is rising long after midnight the meteor rates will have vastly reduced, though it may be worth shooting star-gazing after August 19, 2022.
When is the Perseid meteor shower in 2023?
The Perseid meteor shower will next year peak—in thankfully moonless skies—at around 07:00 UT on August 13, 2023 (so 03:00 EST and midnight PST), which will be ideal for North America.
Wishing you clear skies and wide eyes.
Meet Qikiqtania, a fossil fish who stayed in the water while others ventured onto land – Big Think
Approximately 365 million years ago, one group of fishes left the water to live on land. These animals were early tetrapods, a lineage that would radiate to include many thousands of species including amphibians, birds, lizards and mammals. Human beings are descendants of those early tetrapods, and we share the legacy of their water-to-land transition.
But what if, instead of venturing onto the shores, they had turned back? What if these animals, just at the cusp of leaving the water, had receded to live again in more open waters?
A new fossil suggests that one fish, in fact, did just that. In contrast to other closely related animals, which were using their fins to prop their bodies up on the bottom of the water and perhaps occasionally venturing out onto land, this newly discovered creature had fins that were built for swimming.
In March 2020, I was at The University of Chicago and a member of biologist Neil Shubin’s lab. I was working with Justin Lemberg, another researcher in our group, to process a fossil that was collected back in 2004 during an expedition to the Canadian Arctic.
From the surface of the rock it was embedded in, we could see fragments of the jaws, about 2 inches long (5 cm) and with pointed teeth. There were also patches of white scales with bumpy texture. The anatomy gave us subtle hints that the fossil was an early tetrapod. But we wanted to see inside the rock.
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So we used a technology called CT scanning, which shoots X-rays through the specimen, to look for anything that might be hidden within, out of view. On March 13, we scanned an unassuming piece of rock that had a few scales on top and discovered it contained a complete fin buried inside. Our jaws dropped. A few days later, the lab and campus shut down, and COVID-19 sent us into lockdown.
The fin revealed
A fin like this is extremely precious. It can give scientists clues into how early tetrapods were evolving and how they were living hundreds of millions of years ago. For example, based on the shape of certain bones in the skeleton, we can make predictions about whether an animal was swimming or walking.
Although that first scan of the fin was promising, we needed to see the skeleton in high resolution. As soon as we were allowed back on campus, a professor in the university’s department of the geophysical sciences helped us to trim down the block using a rock saw. This made the block more fin, less rock, allowing for a better scan and a closer view of the fin.
When the dust had cleared and we’d finished analyzing data on the jaws, scales and fin, we realized that this animal was a new species. Not only that, it turns out that this is one of the closest known relatives to limbed vertebrates – those creatures with fingers and toes.
We named it Qikiqtania wakei. Its genus name, pronounced “kick-kiq-tani-ahh,” refers to the Inuktitut words Qikiqtaaluk or Qikiqtani, the traditional name for the region where the fossil was found. When this fish was alive, many hundreds of millions of years ago, this was a warm environment with rivers and streams. Its species name honors the late David Wake, a scientist and mentor who inspired so many of us in the field of evolutionary and developmental biology.
Skeletons tell how an animal lived
Qikiqtania reveals a lot about a critical period in our lineage’s history. Its scales tell researchers unambiguously that it was living underwater. They show sensory canals that would have allowed the animal to detect the flow of water around its body. Its jaws tell us that it was foraging as a predator, biting and holding onto prey with a series of fangs and drawing food into its mouth by suction.
But it is Qikiqtania’s pectoral fin that is most surprising. It has a humerus bone, just as our upper arm does. But Qikiqtania’s has a very peculiar shape.
Early tetrapods, like Tiktaalik, have humeri that possess a prominent ridge on the underside and a characteristic set of bumps, where muscles attach. These bony bumps tell us that early tetrapods were living on the bottom of lakes and streams, using their fins or arms to prop themselves up, first on the ground underwater and later on land.
Qikiqtania’s humerus is different. It lacks those trademark ridges and processes. Instead, its humerus is thin and boomerang-shaped, and the rest of the fin is large and paddle-like. This fin was built for swimming.
Whereas other early tetrapods were playing at the water’s edge, learning what land had to offer, Qikiqtania was doing something different. Its humerus is truly unlike any others known. My colleagues and I think it shows that Qikiqtania had turned back from the water’s edge and evolved to live, once again, off the ground and in open water.
Evolution isn’t a march in one direction
Evolution isn’t a simple, linear process. Although it might seem like early tetrapods were trending inevitably toward life on land, Qikiqtania shows exactly the limitations of such a directional perspective. Evolution didn’t build a ladder towards humans. It’s a complex set of processes that together grow the tangled tree of life. New species form and they diversify. Branches can head off in any number of directions.
This fossil is special for so many reasons. It’s not just miraculous that this fish was preserved in rock for hundreds of millions of years before being discovered by scientists in the Arctic, on Ellesmere Island. It’s not just that it’s remarkably complete, with its full anatomy revealed by serendipity at the cusp of a global pandemic. It also provides, for the first time, a glimpse of the broader diversity and range of lifestyles of fishes at the water-to-land transition. It helps researchers see more than a ladder and understand that fascinating, tangled tree.
Discoveries depend on community
Qikiqtania was found on Inuit land, and it belongs to that community. My colleagues and I were only able to conduct this research because of the generosity and support of individuals in the hamlets of Resolute Bay and Grise Fiord, the Iviq Hunters and Trappers of Grise Fiord, and the Department of Heritage and Culture, Nunavut. To them, on behalf of our entire research team, “nakurmiik.” Thank you. Paleontological expeditions onto their land have truly changed how we understand the history of life on Earth.
COVID-19 kept many paleontologists from traveling and visiting field sites across the world these last few years. We’re eager to return, to visit with old friends and to search again. Who knows what other animals lie hidden, waiting to be discovered inside blocks of unassuming stone.
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