Scientists: Jellies Are the Oldest Animals on Earth

Bastique via Wikimedia Commons // CC BY-SA 3.0
Bastique via Wikimedia Commons // CC BY-SA 3.0

One of the hottest debates in science today concerns two very, very chill animals. Some scientists argue that sea sponges were the first-ever animals to evolve; others say jellies came first. There’s evidence to support both sides, but the latest research, published in the new journal Nature Ecology and Evolution, lands hard in favor of Team Jelly.

Sponges and comb jellies like the one shown above are certainly uncomplicated animals. Both have bodies that are essentially modified tubes, with no eyes, no brains, and no hearts. It might not be an exciting setup, but it’s been working out for these animals for millions and millions of years.

Determining the exact age of a boneless animal is much harder than dating, say, a dinosaur. After death, soft bodies essentially melt away, leaving almost no clues behind—except for the genes they’ve passed down to the next generation. Each animal’s genes is like a map of its evolutionary history. The trick is figuring out how to read it accurately.

Paper co-author Antonis Rokas is an evolutionary biologist at Vanderbilt University. He and his team had grown dissatisfied with existing phylogenomic (genetic map-reading) techniques, which can yield incomplete or ambiguous results.

“The current method that scientists use in phylogenomic studies is to collect large amounts of genetic data, analyze the data, build a set of relationships and then argue that their conclusions are correct because of various improvements they have made in their analysis,” Rokas said in a statement. “This has worked extremely well in 95 percent of the cases, but it has led to apparently irreconcilable differences in the remaining 5 percent."

What was needed, the researchers decided, was a more precise instrument, one that used only the most pertinent information instead of huge piles of data. In this case, that meant looking only at the relationships between different animals’ genetic maps.

“When you look at a particular gene in an organism, let's call it A,” Rokas said, “we ask if it is most closely related to its counterpart in organism B? Or to its counterpart in organism C? And by how much?"

The researchers say the results of this new tactic are clearer and more decisive than any research on the subject to date. And those results say comb jellies, not sponges, were the first animals to evolve.

"We believe that our approach can help resolve many of these long-standing controversies and raise the game of phylogenetic reconstruction to a new level," Rokas said.

Does the Full Moon Really Make People Act Crazy?

iStock.com/voraorn
iStock.com/voraorn

Along with Mercury in retrograde, the full moon is a pretty popular scapegoat for bad luck and bizarre behavior. Encounter someone acting strangely? Blame it on the lunar phases! It's said that crime rates increase and emergency rooms are much busier during the full moon (though a 2004 study debunked this claim). Plus, there's that whole werewolf thing. Why would this be? The reasoning is that the Moon, which affects the ocean's tides, probably exerts a similar effect on us, because the human body is made mostly of water.

This belief that the Moon influences behavior is so widely held—reportedly, even 80 percent of nurses and 64 percent of doctors think it's true, according to a 1987 paper published in the Journal of Emergency Medicine [PDF]—that in 2012 a team of researchers at Université Laval's School of Psychology in Canada decided to find out if mental illness and the phases of the Moon are linked [PDF].

To test the theory, the researchers evaluated 771 patients who visited emergency rooms at two hospitals in Montreal between March 2005 and April 2008. The patients chosen complained of chest pains, which doctors could not determine a medical cause for the pains. Many of the patients suffered from panic attacks, anxiety and mood disorders, or suicidal thoughts.

When the researchers compared the time of the visits to the phases of the Moon, they found that there was no link between the incidence of psychological problems and the four lunar phases, with one exception—in the last lunar quarter, anxiety disorders were 32 percent less frequent. "This may be coincidental or due to factors we did not take into account," Dr. Geneviève Belleville, who directed the team of researchers, said. "But one thing is certain: we observed no full-moon or new-moon effect on psychological problems."

So rest easy (or maybe not): If people seem to act crazy during the full Moon, their behavior is likely pretty similar during the rest of the lunar cycle as well.

This story was updated in 2019.

NASA Reveals How Living in Space for a Year Affected Scott Kelly’s Poop

NASA, Getty Images
NASA, Getty Images

When you agree to be part of a yearlong space study, you forfeit some right to privacy. In astronaut Scott Kelly’s case, the changes his body endured while spending a year at the International Space Station (ISS) were carefully analyzed by NASA, then published in a scientific journal for all to see. Kelly submitted blood samples, saliva samples, and cheek swabs. Even his poop was subjected to scrutiny.

As PBS reports, Scott Kelly’s fecal samples revealed that his gut microbiome underwent significant but reversible changes during his time in orbit. In what was surely good news for both Kelly and NASA, his gut bacteria didn’t contain anything “alarming or scary,” according to geneticist Martha Hotz Vitaterna, and it returned to normal within six months of landing on Earth.

Even after being subjected to the challenging conditions of space, “Scott’s microbiome still looked like Scott’s microbiome, just with a space twist on it,” said Vitaterna, who was one of the study’s authors.

The fecal probe was one small part of a sweeping NASA study that was just published in the journal Science, more than three years after Kelly’s return. Dubbed the Twins Study, it hinged on the results of Kelly’s tests being compared with those of his identical twin, retired astronaut Mark Kelly, who remained on Earth as the control subject.

NASA’s goal was to gain insight into the hazards that astronauts could face on proposed long-term missions to the Moon and Mars. The agency has gone to great lengths to get this information, including offering to pay people $18,500 to stay in bed for two months in order to replicate the conditions of anti-gravity.

It also explains why NASA was willing to launch unmanned rockets into space to collect samples of Kelly’s poop. On four different occasions at the ISS, Kelly used cotton swabs to pick up poo particles. When the rockets arrived to drop off lab supplies, they returned to Earth with little tubes containing the swabs, which had to be frozen until all of the samples were collected. The process was tedious, and on one occasion, one of the SpaceX rockets exploded shortly after it launched in 2015.

The study also found that his telomeres, the caps at the ends of chromosomes, had lengthened in space, likely due to regular exercise and a proper diet, according to NASA. But when Kelly returned to Earth, they began to shorten and return to their pre-spaceflight length. Shorter telomeres have a correlation with aging and age-related diseases. “Although average telomere length, global gene expression, and microbiome changes returned to near preflight levels within six months after return to Earth, increased numbers of short telomeres were observed and expression of some genes was still disrupted,” researchers wrote.

Researchers say more studies will be needed before they send the first human to Mars. Check out NASA's video below to learn more about what they discovered.

[h/t PBS]

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