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.
Every bit of information we know about the world we gathered with one of our five senses. But even with perfect pitch or 20/20 vision, our perceptions don’t always reflect an accurate picture of our surroundings. Our brain is constantly filling in gaps and taking shortcuts, which can result in some pretty wild illusions.
That’s the subject of “Our Senses: An Immersive Experience,” a new exhibition at the American Museum of Natural History in New York City. Mental Floss recently took a tour of the sensory funhouse to learn more about how the brain and the senses interact.
1. LIGHTING REVEALS HIDDEN IMAGES.
Under normal lighting, the walls of the first room of “Our Senses” look like abstract art. But when the lights change color, hidden illustrations are revealed. The three lights—blue, red, and green—used in the room activate the three cone cells in our eyes, and each color highlights a different set of animal illustrations, giving the viewers the impression of switching between three separate rooms while standing still.
2. CERTAIN SOUNDS TAKE PRIORITY ...
We can “hear” many different sounds at once, but we can only listen to a couple at a time. The AMNH exhibit demonstrates this with an audio collage of competing recordings. Our ears automatically pick out noises we’re conditioned to react to, like an ambulance siren or a baby’s cry. Other sounds, like individual voices and musical instruments, require more effort to detect.
3. ... AS DO CERTAIN IMAGES.
When looking at a painting, most people’s eyes are drawn to the same spots. The first things we look for in an image are human faces. So after staring at an artwork for five seconds, you may be able to say how many people are in it and what they look like, but would likely come up short when asked to list the inanimate object in the scene.
4. PAST IMAGES AFFECT PRESENT PERCEPTION.
Our senses often are more suggestible than we would like. Check out the video above. After seeing the first sequence of animal drawings, do you see a rat or a man’s face in the last image? The answer is likely a rat. Now watch the next round—after being shown pictures of faces, you might see a man’s face instead even though the final image hasn’t changed.
5. COLOR INFLUENCES TASTE ...
Every cooking show you’ve watched is right—presentation really is important. One look at something can dictate your expectations for how it should taste. Researchers have found that we perceive red food and drinks to taste sweeter and green food and drinks to taste less sweet regardless of chemical composition. Even the color of the cup we drink from can influence our perception of taste.
6. ... AND SO DOES SOUND
Sight isn’t the only sense that plays a part in how we taste. According to one study, listening to crunching noises while snacking on chips makes them taste fresher. Remember that trick before tossing out a bag of stale junk food.
7. BEING HYPER-FOCUSED HAS DRAWBACKS.
Have you ever been so focused on something that the world around you seemed to disappear? If you can’t recall the feeling, watch the video above. The instructions say to keep track of every time a ball is passed. If you’re totally absorbed, you may not notice anything peculiar, but watch it a second time without paying attention to anything in particular and you’ll see a person in a gorilla suit walk into the middle of the screen. The phenomenon that allows us to tune out big details like this is called selective attention. If you devote all your mental energy to one task, your brain puts up blinders that block out irrelevant information without you realizing it.
8. THINGS GET WEIRD WHEN SENSES CONTRADICT EACH OTHER.
The most mind-bending room in the "Our Senses" exhibit is practically empty. The illusion comes from the black grid pattern painted onto the white wall in such a way that straight planes appear to curve. The shapes tell our eyes we’re walking on uneven ground while our inner ear tells us the floor is stable. It’s like getting seasick in reverse: This conflicting sensory information can make us feel dizzy and even nauseous.
If our brains didn’t know how to adjust for lighting, we’d see every shadow as part of the object it falls on. But we can recognize that the half of a street that’s covered in shade isn’t actually darker in color than the half that sits in the sun. It’s a pretty useful adaptation—except when it’s hijacked for optical illusions. Look at the image above: The squares marked A and B are actually the same shade of gray. Because the pillar appears to cast a shadow over square B, our brain assumes it’s really lighter in color than what we’re shown.
10. WE SEE FACES EVERYWHERE.
The human brain is really good at recognizing human faces—so good it can make us see things that aren’t there. This is apparent in the Einstein hollow head illusion. When looking at the mold of Albert Einstein’s face straight on, the features appear to pop out rather than sink in. Our brain knows we’re looking at something similar to a human face, and it knows what human faces are shaped like, so it automatically corrects the image that it’s given.
All images courtesy of the American Museum of Natural History unless otherwise noted.
More Details Emerge About 'Oumuamua, Earth's First-Recorded Interstellar Visitor
BY Kirstin Fawcett
November 21, 2017
In October, scientists using the University of Hawaii's Pan-STARRS 1 telescope sighted something extraordinary: Earth's first confirmed interstellar visitor. Originally called A/2017 U1, the once-mysterious object has a new name—'Oumuamua, according toScientific American—and researchers continue to learn more about its physical properties. Now, a team from the University of Hawaii's Institute of Astronomy has published a detailed report of what they know so far in Nature.
Fittingly, "'Oumuamua" is Hawaiian for "a messenger from afar arriving first." 'Oumuamua's astronomical designation is 1I/2017 U1. The "I" in 1I/2017 stands for "interstellar." Until now, objects similar to 'Oumuamua were always given "C" and "A" names, which stand for either comet or asteroid. New observations have researchers concluding that 'Oumuamua is unusual for more than its far-flung origins.
It's a cigar-shaped object 10 times longer than it is wide, stretching to a half-mile long. It's also reddish in color, and is similar in some ways to some asteroids in our solar system, the BBC reports. But it's much faster, zipping through our system, and has a totally different orbit from any of those objects.
After initial indecision about whether the object was a comet or an asteroid, the researchers now believe it's an asteroid. Long ago, it might have hurtled from an unknown star system into our own.
'Oumuamua may provide astronomers with new insights into how stars and planets form. The 750,000 asteroids we know of are leftovers from the formation of our solar system, trapped by the Sun's gravity. But what if, billions of years ago, other objects escaped? 'Oumuamua shows us that it's possible; perhaps there are bits and pieces from the early years of our solar system currently visiting other stars.
The researchers say it's surprising that 'Oumuamua is an asteroid instead of a comet, given that in the Oort Cloud—an icy bubble of debris thought to surround our solar system—comets are predicted to outnumber asteroids 200 to 1 and perhaps even as high as 10,000 to 1. If our own solar system is any indication, it's more likely that a comet would take off before an asteroid would.
So where did 'Oumuamua come from? That's still unknown. It's possible it could've been bumped into our realm by a close encounter with a planet—either a smaller, nearby one, or a larger, farther one. If that's the case, the planet remains to be discovered. They believe it's more likely that 'Oumuamua was ejected from a young stellar system, location unknown. And yet, they write, "the possibility that 'Oumuamua has been orbiting the galaxy for billions of years cannot be ruled out."
As for where it's headed, The Atlantic's Marina Koren notes, "It will pass the orbit of Jupiter next May, then Neptune in 2022, and Pluto in 2024. By 2025, it will coast beyond the outer edge of the Kuiper Belt, a field of icy and rocky objects."
Last month, University of Wisconsin–Madison astronomer Ralf Kotulla and scientists from UCLA and the National Optical Astronomy Observatory (NOAO) used the WIYN Telescope on Kitt Peak, Arizona, to take some of the first pictures of 'Oumuamua. You can check them out below.
Images of 'Oumuamua—an asteroid or a comet—were captured on October 27.
WIYN OBSERVATORY/RALF KOTULLA
The green circles highlight the position of U1 in each image against faint streaks of background stars. In these images, U1 is about 10 million times fainter than the faintest visible stars.
R. Kotulla (University of Wisconsin) & WIYN/NOAO/AURA/NSF
Color image of U1.
R. Kotulla (University of Wisconsin) & WIYN/NOAO/AURA/NSF