Aliens in our midst

Douglas Fox writes: Leonid Moroz has spent two decades trying to wrap his head around a mind-boggling idea: even as scientists start to look for alien life in other planets, there might already be aliens, with surprisingly different biology and brains, right here on Earth. Those aliens have hidden in plain sight for millennia. They have plenty to teach us about the nature of evolution, and what to expect when we finally discover life on other worlds.

Moroz, a neuroscientist, saw the first hint of his discovery back in the summer of 1995, not long after arriving in the United States from his native Russia. He spent that summer at the Friday Harbor marine laboratory in Washington. The lab sat amid an archipelago of forested islands in Puget Sound – a crossroads of opposing tides and currents that carried hundreds of animal species past the rocky shore: swarms of jellyfish, amphipod crustaceans, undulating sea lilies, nudibranch slugs, flatworms, and the larvae of fish, sea stars and countless other animals. These creatures represented not just the far reaches of Puget Sound, but also the farthest branches of the animal tree of life. Moroz spent hours out on the pier behind the lab, collecting animals so he could study their nerves. He had devoted years to studying nervous systems across the animal kingdom, in hopes of understanding the evolutionary origin of brains and intelligence. But he came to Friday Harbor to find one animal in particular.

He trained his eyes to recognise its bulbous, transparent body in the sunlit water: an iridescent glint and fleeting shards of rainbow light, scattered by the rhythmic beating of thousands of hair-like cilia, propelling it through the water. This type of animal, called a ctenophore (pronounced ‘ten-o-for’ or ‘teen-o-for’), was long considered just another kind of jellyfish. But that summer at Friday Harbor, Moroz made a startling discovery: beneath this animal’s humdrum exterior was a monumental case of mistaken identity. From his very first experiments, he could see that these animals were unrelated to jellyfish. In fact, they were profoundly different from any other animal on Earth.

Moroz reached this conclusion by testing the nerve cells of ctenophores for the neurotransmitters serotonin, dopamine and nitric oxide, chemical messengers considered the universal neural language of all animals. But try as he might, he could not find these molecules. The implications were profound.

The ctenophore was already known for having a relatively advanced nervous system; but these first experiments by Moroz showed that its nerves were constructed from a different set of molecular building blocks – different from any other animal – using ‘a different chemical language’, says Moroz: these animals are ‘aliens of the sea’.

If Moroz is right, then the ctenophore represents an evolutionary experiment of stunning proportions, one that has been running for more than half a billion years. This separate pathway of evolution – a sort of Evolution 2.0 – has invented neurons, muscles and other specialised tissues, independently from the rest of the animal kingdom, using different starting materials. [Continue reading…]

Facebooktwittermail

First support for a physics theory of life

Natalie Wolchover writes: The biophysicist Jeremy England made waves in 2013 with a new theory that cast the origin of life as an inevitable outcome of thermodynamics. His equations suggested that under certain conditions, groups of atoms will naturally restructure themselves so as to burn more and more energy, facilitating the incessant dispersal of energy and the rise of “entropy” or disorder in the universe. England said this restructuring effect, which he calls dissipation-driven adaptation, fosters the growth of complex structures, including living things. The existence of life is no mystery or lucky break, he told Quanta in 2014, but rather follows from general physical principles and “should be as unsurprising as rocks rolling downhill.”

Since then, England, a 35-year-old associate professor at the Massachusetts Institute of Technology, has been testing aspects of his idea in computer simulations. The two most significant of these studies were published this month — the more striking result in the Proceedings of the National Academy of Sciences (PNAS) and the other in Physical Review Letters (PRL). The outcomes of both computer experiments appear to back England’s general thesis about dissipation-driven adaptation, though the implications for real life remain speculative.

“This is obviously a pioneering study,” Michael Lässig, a statistical physicist and quantitative biologist at the University of Cologne in Germany, said of the PNAS paper written by England and an MIT postdoctoral fellow, Jordan Horowitz. It’s “a case study about a given set of rules on a relatively small system, so it’s maybe a bit early to say whether it generalizes,” Lässig said. “But the obvious interest is to ask what this means for life.”

The paper strips away the nitty-gritty details of cells and biology and describes a simpler, simulated system of chemicals in which it is nonetheless possible for exceptional structure to spontaneously arise — the phenomenon that England sees as the driving force behind the origin of life. “That doesn’t mean you’re guaranteed to acquire that structure,” England explained. The dynamics of the system are too complicated and nonlinear to predict what will happen. [Continue reading…]

Facebooktwittermail

Half the atoms inside and around us came from outside the Milky Way

The Guardian reports: Nearly half of the atoms that make up our bodies may have formed beyond the Milky Way and travelled to the solar system on intergalactic winds driven by giant exploding stars, astronomers claim.

The dramatic conclusion emerges from computer simulations that reveal how galaxies grow over aeons by absorbing huge amounts of material that is blasted out of neighbouring galaxies when stars explode at the end of their lives.

Powerful supernova explosions can fling trillions of tonnes of atoms into space with such ferocity that they escape their home galaxy’s gravitational pull and fall towards larger neighbours in enormous clouds that travel at hundreds of kilometres per second.

Astronomers have long known that elements forged in stars can travel from one galaxy to another, but the latest research is the first to reveal that up to half of the material in the Milky Way and similar-sized galaxies can arrive from smaller galactic neighbours.

Much of the hydrogen and helium that falls into galaxies forms new stars, while heavier elements, themselves created in stars and dispersed in the violent detonations, become the raw material for building comets and asteroids, planets and life. [Continue reading…]

Facebooktwittermail

New study finds as many as ‘50% of the number of animal individuals that once shared Earth with us are already gone’

Ed Yong writes: Imagine if every animal and plant on the planet collapsed into a single population each, says ecologist Gerardo Ceballos. If lions disappeared except from one small corner of Kenya, the prey they keep in check would run amok everywhere else. If sparrows were no more except in one Dutch forest, the seeds that sparrows disperse would stay in place everywhere else. If honeybees became isolated to one American meadow, the flowers that they pollinate would fail to reproduce everywhere else. None of those species would be extinct per se, “but we’d still be in very bad shape,” says Ceballos.

He uses this thought experiment to show that fixating on the concept of extinction can lead scientists to overestimate the state of the planet’s health. Extinction obviously matters. If a species is completely wiped out, that’s an important and irreversible loss. But that flip from present to absent, extant to extinct, is just the endpoint of a long period of loss. Before a species disappears entirely, it first disappears locally. And each of those local extinctions—or extirpations—also matters.

“If jaguars become extinct in Mexico, it doesn’t matter if there are still jaguars in Brazil for the role that jaguars play in Mexican ecosystems,” says Ceballos. “Or we might able to keep California condors alive forever, but if there are just 10 or 12 individuals, they won’t be able to survive without human intervention. We’re missing the point when we focus just on species extinction.”

He and his colleagues, Paul Ehrlich and Rodolfo Dirzo, have now tried to quantify those local losses. First, they analyzed data for some 27,600 species of land-based vertebrates, and found that a third of these are in decline. That doesn’t mean they are endangered: A third of these declining species are listed as “low concern” by the International Union for Conservation of Nature, meaning that they aren’t in immediate peril. But that, according to Ceballos’s team, provides a false sense of security. Barn swallows, for example, still number in the millions, but those numbers are going down, and the birds are disappearing from many parts of their range. “Even these common species are declining,” says Ceballos. “Eventually, they’ll become endangered, and eventually they’ll be extinct.”

The team also analyzed detailed historical data for 177 species of mammals. In the last century, every one of these species has lost at least 30 percent of its historical range, and almost half have lost more than 80 percent. Consider the lion. If you divide the world’s land into a grid of 22,000 sectors, each containing 10,000 square kilometers, around 2,000 of those would have been home to lions at the start of the 20th century. Now, just 600 of them are. These royal beasts, which once roamed all over Africa and all the way from southern Europe to northern India, are now confined to pockets of sub-Saharan Africa, and a single Indian forest. Their numbers have fallen by 43 percent in the last two decades.

Several other species that were once thought to be safe are also now endangered. Since the 1980s, the giraffe population has fallen by up to 40 percent, from at least 152,000 animals to just 98,000 in 2015. In the last decade, savanna elephant numbers have fallen by 30 percent, and 80 percent of forest elephants were slaughtered in a national park that was one of their last strongholds. Cheetahs are down to their last 7,000 individuals, and orangutans to their last 5,000.

All told, “as much as 50 percent of the number of animal individuals that once shared Earth with us are already gone, as are billions of populations,” Ceballos and his colleagues write. “While the biosphere is undergoing mass species extinction, it is also being ravaged by a much more serious and rapid wave of population declines and extinctions.” [Continue reading…]

Facebooktwittermail

Can microbes encourage altruism?

Elizabeth Svoboda writes: Parasites are among nature’s most skillful manipulators — and one of their specialties is making hosts perform reckless acts of irrational self-harm. There’s Toxoplasma gondii, which drives mice to seek out cats eager to eat them, and the liver fluke Dicrocoelium dendriticum, which motivates ants to climb blades of grass, exposing them to cows and sheep hungry for a snack. There’s Spinochordodes tellinii, the hairworm that compels crickets to drown themselves so the worm can access the water it needs to breed. The hosts’ self-sacrifice gains them nothing but serves the parasites’ hidden agenda, enabling them to complete their own life cycle.

Now researchers are beginning to explore whether parasitic manipulations may spur host behaviors that are selfless rather than suicidal. They are wondering whether microbes might be fundamentally responsible for many of the altruistic behaviors that animals show toward their own kind. Altruism may seem easy to justify ethically or strategically, but explaining how it could have persisted in a survival-of-the-fittest world is surprisingly difficult and has puzzled evolutionary theorists going all the way back to Darwin. If microbes in the gut or other tissues can nudge their hosts toward generosity for selfish reasons of their own, altruism may become less enigmatic.

A recently developed mathematical model and related computer simulations by a trio of researchers at Tel Aviv University appear to validate this theory. The researchers showed that transmissible microbes that promoted altruism in their hosts won the survival battle over microbes that did not — and when this happened, altruism became a stable trait in the host population. The research was published in Nature Communications earlier this year.

“The story is fascinating, because we don’t think of altruism in terms of the host-microbiome relationship,” said John Bienenstock, a biologist at McMaster University in Hamilton, Ontario, and director of the Brain-Body Institute at St. Joseph’s Healthcare Hamilton, who was not involved with the simulation work. “You can’t ignore the possible effect of what your bug population is doing.” [Continue reading…]

Facebooktwittermail

Daniel Everett: Becoming human without words for colors, numbers, or time

 

Facebooktwittermail

Life-giving chemical compound found orbiting infant stars in space

AFP reports: Two teams of astronomers said Thursday that they have for the first time detected a key chemical building block of life swirling around infant stars that resemble our sun before its planets formed.

The molecule, methyl isocyanate, “plays an essential role in the formation of proteins, which are basic ingredients for life,” said Victor Rivilla, a scientist at the Astrophysics Observatory in Florence, Italy, and co-author of a study published in Monthly Notices of the Royal Astronomical Society.

The findings could offer clues on how chemicals sparked into living matter on Earth several billion years ago.

At the very least, they show that elements crucial for the emergence of life “were very likely already available at the earliest stage of solar system formation,” said Niels Ligterink, a researcher at Leiden Observatory in the Netherlands and lead author of a second study in the same journal. [Continue reading…]

Facebooktwittermail

Manchester spirit: Tony Walsh recites ‘This Is The Place’ at a vigil for the bombing victims

HuffPost: Poet Tony Walsh became an instant symbol of Manchester’s defiance in the face of terror after reading his powerful ode to the city at a vigil to victims of the Manchester bombing.

Addressing thousands gathered at Manchester’s central Albert Square, the poet – known as ‘Longfella’ – gave a recital of his poem This Is The Place that paid tribute to the city’s rich history as an industrial and musical powerhouse. [Continue reading…]

Facebooktwittermail

Human noise is making it harder for birds and animals to hear each other

Science News reports: Even in the wilderness, humans are making a ruckus.

In 63 percent of America’s protected places — including parks, monuments and designated wilderness areas — sounds made by human activity are doubling the volume of background noise. And in 21 percent of protected places, this racket can make things 10 times noisier.

Enough clatter from cars, planes and suburban sprawl is seeping into wild places to diminish animals’ ability to hear mating calls and approaching predators, a team of researchers based in Colorado reports in the May 5 Science. Human noise doesn’t always have to be loud to override natural sounds, though. Some places are so quiet to begin with that even the smallest amount of human noise can dominate, the researchers found.

“The world is changing, and protected areas are getting louder — the last strongholds of diversity,” says Jesse Barber, an ecologist at Boise State University in Idaho. Studies like this one that show the impact of human-related noise across the entire country instead of in a single park are important, he says, because “this is the scale at which conservation occurs.” [Continue reading…]

Facebooktwittermail

Morning glory seeds are tough enough for an interplanetary trip

Katherine Kornei writes: Natural sunscreens help morning glory seeds survive doses of ultraviolet (UV) radiation that would burn most humans to a crisp, according to a new study. The hardy seeds of the common flowering plant would probably even survive a voyage between planets, say the researchers. This might help researchers decide which species to send on future missions to Mars, a place that is bombarded with UV light because of its thin atmosphere. It also validates the concept of panspermia, the idea that life might have hopscotched through our solar system—or others—by hitching a ride on asteroids or comets.

“These results add to the fast-growing body of evidence showing that panspermia is not only possible, but absolutely inevitable,” says Chandra Wickramasinghe, director of the Buckingham Centre for Astrobiology at the University of Buckingham in the United Kingdom, who was not involved in the study.

The research began a decade ago, when astronauts placed about 2000 seeds from tobacco plants and a flowering plant known as Arabidopsis thaliana on the outside of the International Space Station. For 558 days, the seeds were exposed to high levels of UV light, cosmic radiation, and extreme temperature fluctuations—conditions that are lethal to most forms of life. [Continue reading…]

Facebooktwittermail

On the happy life

Massimo Pigliucci writes: Lucius Annaeus Seneca is a towering and controversial figure of antiquity. He lived from 4 BCE to 65 CE, was a Roman senator and political adviser to the emperor Nero, and experienced exile but came back to Rome to become one of the wealthiest citizens of the Empire. He tried to steer Nero toward good governance, but in the process became his indirect accomplice in murderous deeds. In the end, he was ‘invited’ to commit suicide by the emperor, and did so with dignity, in the presence of his friends.

Seneca wrote a number of tragedies that directly inspired William Shakespeare, but was also one of the main exponents of the Stoic school of philosophy, which has made a surprising comeback in recent years. Stoicism teaches us that the highest good in life is the pursuit of the four cardinal virtues of practical wisdom, temperance, justice and courage – because they are the only things that always do us good and can never be used for ill. It also tells us that the key to a serene life is the realisation that some things are under our control and others are not: under our control are our values, our judgments, and the actions we choose to perform. Everything else lies outside of our control, and we should focus our attention and efforts only on the first category.

Seneca wrote a series of philosophical letters to his friend Lucilius when he was nearing the end of his life. The letters were clearly meant for publication, and represent a sort of philosophical testament for posterity. I chose letter 92, ‘On the Happy Life’, because it encapsulates both the basic tenets of Stoic philosophy and some really good advice that is still valid today.

The first thing to understand about this letter is the title itself: ‘happy’ here does not have the vague modern connotation of feeling good, but is the equivalent of the Greek word eudaimonia, recently adopted also by positive psychologists, and which is best understood as a life worth living. [Continue reading…]

Facebooktwittermail

Trees have their own songs

Ed Yong writes: Just as birders can identify birds by their melodious calls, David George Haskell can distinguish trees by their sounds. The task is especially easy when it rains, as it so often does in the Ecuadorian rainforest. Depending on the shapes and sizes of their leaves, the different plants react to falling drops by producing “a splatter of metallic sparks” or “a low, clean, woody thump” or “a speed-typist’s clatter.” Every species has its own song. Train your ears (and abandon the distracting echoes of a plastic rain jacket) and you can carry out a botanical census through sound alone.

“I’ve taught ornithology to students for many years,” says Haskell, a natural history writer and professor of biology at Sewanee. “And I challenge my students: Okay, now that you’ve learned the songs of 100 birds, your task is to learn the sounds of 20 trees. Can you tell an oak from a maple by ear? I have them go out, pour their attention into their ears, and harvest sounds. It’s an almost meditative experience. And from that, you realize that trees sound different, and they have amazing sounds coming from them. Our unaided ears can hear how a maple tree changes its voice as a soft leaves of early spring change into the dying one of autumn.”

This acoustic world is open to everyone, but most of us never enter it. It just seems so counter-intuitive—not to mention a little hokey—to listen to trees. But Haskell does listen, and he describes his experiences with sensuous prose in his enchanting new book The Songs of Trees. A kind of naturalist-poet, Haskell makes a habit of returning to the same places and paying “repeated sensory attention” to them. “I like to sit down and listen, and turn off the apps that come pre-installed in my body,” he says. Humans may be a visual species, but “sounds reveals things that are hidden from our eyes because the vibratory energy of the world comes around barriers and through the ground. Through sound, we come to know the place.” [Continue reading…]

Facebooktwittermail

The benefits of solitude

Michael Harris writes: On April 14, 1934, Richard Byrd went out for his daily walk. The air was the usual temperature: minus 57 degrees Fahrenheit. He stepped steadily through the drifts of snow, making his rounds. And then he paused to listen. Nothing.

He attended, a little startled, to the cloud-high and over-powering silence he had stepped into. For miles around the only other life belonged to a few stubborn microbes that clung to sheltering shelves of ice. It was only 4 p.m., but the land quavered in a perpetual twilight. There was—was there?—some play on the chilled horizon, some crack in the bruised Antarctic sky. And then, unaccountably, Richard Byrd’s universe began to expand.

Later, back in his hut, huddled by a makeshift furnace, Byrd wrote in his diary:

Here were imponderable processes and forces of the cosmos, harmonious and soundless. Harmony, that was it! That was what came out of the silence—a gentle rhythm, the strain of a perfect chord, the music of the spheres, perhaps.

It was enough to catch that rhythm, momentarily to be myself a part of it. In that instant I could feel no doubt of man’s oneness with the universe.

Admiral Byrd had volunteered to staff a weather base near the South Pole for five winter months. But the reason he was there alone was far less concrete. Struggling to explain his reasons, Byrd admitted that he wanted “to know that kind of experience to the full . . . to taste peace and quiet and solitude long enough to find out how good they really are.” He was also after a kind of personal liberty, for he believed that “no man can hope to be completely free who lingers within reach of familiar habits.” [Continue reading…]

Facebooktwittermail

Cosmic speck: Earth as seen from Saturn

 

Space.com reports: The Cassini spacecraft spotted Earth as a bright speck (and the moon as a smaller speck) between Saturn’s broad rings as the craft prepares for its final dive into the ringed planet’s atmosphere.

Cassini was 870 million miles (1.4 billion kilometers) from Earth the night of April 12-13 when it snapped this photo, which shows Earth — and the even tinier moon, a faint dot to its left — framed between the icy rings of Saturn. At the time the photo was taken, the southern Atlantic Ocean was facing the spacecraft’s lens, NASA officials said in a statement. [Continue reading…]

Facebooktwittermail

Small Saturn moon has most of conditions needed to sustain life, NASA says

The Guardian reports: A tiny moon of Saturn has most of the conditions necessary for life, Nasa announced on Thursday, unveiling a discovery from an underground ocean that makes the world a leading candidate for organisms as humans know them.

Scientists stressed that the discovery on a moon named Enceladus is not evidence that life has in fact developed on another world, but they have managed to establish the existence of the water, chemistry and energy sources that are necessary for it.

“We now know that Enceladus has almost all of the ingredients that you need to support life as we know it on Earth,” said Linda Spilker, a project scientist who said the finding essentially confirmed vents on the moon’s seafloor.

Chris Glein, another scientist involved in the project, said the discovery showed that the moon’s ocean contained a potential chemical feast for microbes. “We have made the first calorie count on an alien ocean,” he said.

Beneath its frozen surface, Enceladus has a saltwater ocean, and the hydrogen – produced in a reaction between heated water and rocks – indicates that the moon has active energy sources, possibly akin to the undersea vents that teem with life on planet Earth.

“We don’t know whether there’s life out there yet but right now we’re making a lot of progress,” said Thomas Zurbuchen, Nasa’s associate administrator.

The spacecraft Cassini detected the hydrogen in the fall of 2015, when it flew through a plume of vapor that had been spewed out through cracks in the moon’s icy surface. The flyby discovered water, ice, traces of methane, salts and other carbon compounds, the researchers said.

Their findings were revealed at a Nasa briefing on Thursday and in a paper published in the journal Science.

Cassini also found silicates and hydrogen, meaning there are energy sources beneath the moon’s surface, and the chemicals microbes are known to consume on Earth.

“This finding does not mean that life exists there, but it makes life more plausible and potentially quite abundant if a fraction of the hydrogen is used to drive biology,” said Jeffrey Kargel, a professor at the University of Arizona.

Andrew Coates, a professor of physics at University College London, added: “This distant moon now joins Mars and Europa as the best potential locations for life beyond Earth in our solar system.” [Continue reading…]

 

Facebooktwittermail

Wonders of the deep ocean

The New York Times reports: One of the great treasures in ocean preserves is the Pacific Remote Islands Marine National Monument, established in 2009 and expanded in 2014 to cover about 370,000 square miles.

That’s a lot of water to explore, and this year the research vessel Okeanos Explorer has been doing just that, collecting data and videos on the ocean and some of the astonishing creatures that live there.

The ship is operated by the National Oceanic and Atmospheric Administration, which studies oceans and climate change, among other subjects. Scientists on board the most recent cruise — southwest of Hawaii — used a remotely operated vehicle, the Deep Discoverer, which can descend almost 20,000 feet, to take video of remarkable creatures like the deep water siphonophore. [Continue reading…]

Facebooktwittermail

Biologists say half of all species could be extinct by end of century

The Observer reports: One in five species on Earth now faces extinction, and that will rise to 50% by the end of the century unless urgent action is taken. That is the stark view of the world’s leading biologists, ecologists and economists who will gather on Monday to determine the social and economic changes needed to save the planet’s biosphere.

“The living fabric of the world is slipping through our fingers without our showing much sign of caring,” say the organisers of the Biological Extinction conference held at the Vatican this week.

Threatened creatures such as the tiger or rhino may make occasional headlines, but little attention is paid to the eradication of most other life forms, they argue. But as the conference will hear, these animals and plants provide us with our food and medicine. They purify our water and air while also absorbing carbon emissions from our cars and factories, regenerating soil, and providing us with aesthetic inspiration.

“Rich western countries are now siphoning up the planet’s resources and destroying its ecosystems at an unprecedented rate,” said biologist Paul Ehrlich, of Stanford University in California. “We want to build highways across the Serengeti to get more rare earth minerals for our cellphones. We grab all the fish from the sea, wreck the coral reefs and put carbon dioxide into the atmosphere. We have triggered a major extinction event. The question is: how do we stop it?” [Continue reading…]

Facebooktwittermail