Latest news with #CambrianExplosion
Time of India
24-05-2025
- Science
- Time of India
10 mind-blowing facts about Earth's most amazing creatures
Animals are familiar to us all, not only because we encounter them daily, but also because humans themselves are animals with fascinating truths. We share the planet with an incredible diversity of animal species, many of which play essential roles in our survival and ecosystems. Animals differ from other life forms like plants, fungi, and bacteria in key ways. They are multicellular, usually mobile at some stage, and rely on consuming organic material for energy. Unlike plants, animals lack cell walls and cannot photosynthesize. This unique combination of traits places animals in a distinct category, shaping their interactions with the environment and with each other. Discover 10 fascinating truths about the incredible animals on Earth. Features of animals living on Earth Topic Description Animal life on Earth Animal life began nearly 600 million years ago. Fossils of stromatolites, created by ancient microbes, date back to 3.8 billion years ago, but animals emerged 3.2 billion years later. Early animals like the Ediacara biota appeared during the late Precambrian. Animals and energy Animals are heterotrophs, meaning they must consume other organisms to obtain energy and carbon for survival. They cannot convert sunlight into energy like plants. Movement in animals Most animals can move during at least part of their life cycle. While animals like fish, birds, and mammals are highly mobile, some animals, such as sponges, are sessile or only move during early life stages. Multicellular and eukaryotic All animals are multicellular eukaryotes, meaning they consist of multiple cells and have complex cells with a nucleus and organelles. Most animal cells are organized into tissues such as connective, muscle, epithelial, and nervous tissues. Animal diversity Since their emergence 600 million years ago, animals have evolved into millions of distinct species. Currently, scientists estimate over 3 million living animal species. The Cambrian Explosion The Cambrian Explosion (570-530 million years ago) was a period of rapid diversification, where most of the basic animal body plans that exist today first appeared. Sponges Sponges are the simplest of all animals. They lack specialized tissues and have bodies made up of cells in a gelatinous matrix. They also filter-feed through pores and channels in their bodies. Nerve and muscle cells in animals All animals except sponges have specialized cells called neurons (nerve cells) that transmit electrical signals. Neurons form the basis of complex nervous systems in vertebrates and efficient systems in invertebrates. Symmetry in animals Most animals have symmetrical bodies. Types of symmetry include radial symmetry (as seen in sea urchins and sea stars) and pentaradial symmetry, which is found in some echinoderms like sea stars. The largest living animal The blue whale, a marine mammal weighing over 200 tons, is the largest living animal. Other large animals include the African elephant, Komodo dragon, and colossal squid. Fascinating facts about animals Animal life on Earth began nearly 600 million years ago Life on Earth can be traced back about 3.8 billion years, based on the oldest known evidence. The first fossils discovered are of stromatolites—layered formations created by ancient microbial life. These organisms, however, were not animals. In fact, animals wouldn't make their debut for another 3.2 billion years. It was only during the late Precambrian period that animals began to show up in the fossil record. Among the earliest of these were the Ediacara biota—soft-bodied, frond-like, and tubular organisms that lived between 635 and 543 million years ago. by Taboola by Taboola Sponsored Links Sponsored Links Promoted Links Promoted Links You May Like Incredible: The world's toughest smartwatch designed for the military Indestructible Smartwatch Undo This group appears to have disappeared by the close of the era of Precambrian. Animals extract energy and nutrients by feeding on other organisms Animals require energy to carry out every function essential to life—such as growing, developing, moving, metabolizing, and reproducing. Unlike plants, they lack the ability to convert sunlight into usable energy. Instead, animals are classified as heterotrophs, meaning they must consume plants or other organisms to obtain the carbon and energy necessary for survival. Movement is a key trait of animals While plants remain rooted in place, most animals have the ability to move during at least part of their life cycle. In many animals, this movement is clearly visible—fish glide through water, birds soar through the sky, and mammals walk, climb, or run. However, not all animals are constantly on the move. Some exhibit limited mobility or are mobile only briefly during early life stages. These animals are known as sessile. For example, sponges spend most of their adult lives attached to surfaces, yet their larvae are free-swimming. Some sponge species have also been observed to move extremely slowly—just a few millimeters per day. Other largely immobile animals include barnacles and corals, which show only minimal movement. Every animal is a multicellular eukaryotic organism All animals are made up of multiple cells, meaning they are multicellular organisms. In addition to being multicellular, animals are classified as eukaryotes, as their cells contain complex structures. These eukaryotic cells have internal components, such as the nucleus and various organelles, all enclosed by membranes. The DNA within a eukaryotic cell is organized into linear chromosomes. Except for sponges, which are the simplest animals, animal cells are organized into specialized tissues that carry out different functions. These tissues include connective, muscle, epithelial, and nervous tissues. Animals have evolved into millions of distinct species Since animals first appeared 600 million years ago, their evolution has led to an astonishing variety of life forms. Over time, animals have developed diverse body structures, along with various methods for movement, feeding, and sensing their surroundings. Throughout their evolutionary history, the number of animal groups and species has fluctuated, growing at times and shrinking at others. Currently, scientists estimate that over 3 million species of animals are living today. The Cambrian Explosion stands as a crucial era in animal evolution The Cambrian Explosion, which occurred between 570 and 530 million years ago, was a period of remarkable and rapid animal diversification. During this time, early life forms evolved into a wide range of more complex organisms. Almost all of the fundamental animal body structures that exist today emerged during this era. Sponges are the most basic of all animals Sponges are the most basic of all animals. While they are multicellular like other animals, they differ significantly in other ways. Unlike other animals, sponges do not have specialized tissues. Their bodies are made up of cells embedded in a gelatinous matrix. Within this matrix, tiny spiny structures called spicules provide structural support. Sponges also feature numerous small pores and channels that act as a filter-feeding system, allowing them to capture food from the water. Sponges branched off from all other animal groups early in the evolutionary history of animals. Animals generally have both nerve and muscle cells With the exception of sponges, all animals have specialized cells known as neurons, or nerve cells. Neurons transmit electrical signals to other cells and are responsible for conveying and processing various types of information, including an animal's health, movement, environment, and orientation. In vertebrates, neurons form the foundation of a complex nervous system that includes the sensory system, brain, spinal cord, and peripheral nerves. While invertebrates have fewer neurons compared to vertebrates, their nervous systems are by no means simple. In fact, invertebrate nervous systems are highly efficient and well-adapted to help these animals solve the survival challenges they encounter. Symmetry is a common feature in most animals With the exception of sponges, most animals have symmetrical bodies. Different animal groups display various types of symmetry. One example is radial symmetry, found in cnidarians like sea urchins and some species of sponges. In radial symmetry, an animal's body can be divided into identical halves by more than two planes that run through its length. Animals with radial symmetry typically have a disk, tube, or bowl shape. Echinoderms, such as sea stars, exhibit a specific form of radial symmetry called pentaradial symmetry, which is characterized by five points of symmetry. Among all living animals, the blue whale is the largest animal The blue whale, a marine mammal that can weigh over 200 tons, is the biggest living animal. Other notable large animals include the African elephant, Komodo dragon, and colossal squid. Also read: Coral snake vs King snake: How to identify and differentiate their key traits
Yahoo
15-05-2025
- Science
- Yahoo
Meet the 'sea moth,' a three-eyed sea creature from 500+ million years ago
Scientists have discovered a three-eyed "sea moth" that dates back more than half a billion years ago. Paleontologists Joseph Moysiuk and Jean-Bernard Caron published a study an Wednesday, May 14 that introduces their findings of Mosura fentoni, a new type of radiodont that existed more than 500 million years ago. The "sea moth"-like species caught researchers' attention because of its third, median eye. Scientists named the newly-discovered species "Mosura fentoni," after the fictional Japanese monster kaiju, also known as "Mothra," for its moth-like appearance, the study states. Here's what to know about the newly-discovered deep sea creature. The newly-discovered Mosura fentoni specimen is only about 15 to 61 millimeters long (0.6 to 2.4 inches). The "sea moth" features a short head; small, rounded exoskeleton; three prominent eyes; appendages; large swimming flaps; and densely-packed gills, according to the study. The Mosura fentoni lived during the Cambrian Explosion, which began about 541 million years ago. The Mosura fentoni was a radiodont, a type of arthropod that lived between 520 to 400 million years ago, according to the United Kingdom's Natural History Museum. A popularly known radiodont is Anomalocaris, thought to be one of the first apex predators. Paleontologists believe Mosura fentoni hunted small prey, like shrimp, to avoid competing with other radiodonts in its ecosystem, according to the U.K. Natural History Museum. Mosura fentoni would have used rows of paddle-like fins to glide through the ocean and then use hook-like segments of its feeding appendages to grab small pray and move them through its mouth. While paleontologists are still learning why Mosura fentoni had a third eye, researchers believe the eye may have been used to detect light and the seascape it moved through. Perhaps Mosura fentoni's median eye was similar to that of a dragonfly's extra eyes (yes, dragonflies have five eyes), used to orient themselves during high-speed hunts, according to the U.K. Natural History Museum. A feature of the specimen that has particularly intrigued researchers is its dark, reflective patches, which are called "tonguelettes." Though these structures have been interpreted differently over the years, in Mosura fentoni, researchers believe they suggest structures of an open circulatory system, according to the museum. This means that the Mosura fentoni would have pumped a blood-like substance called haemolymph through a series of body cavities. "Their identity has been controversial, but the well-preserved (body cavities) in Mosura help us to interpret similar, but less clear features that we've seen before in other fossils," Moysiuk told the U.K. museum. "It turns out that preservation of these structures is widespread, confirming the ancient origin of this type of circulatory system." The Mosura fentoni's densely-packed gills also vary from other radiodonts that researchers have studied. These gills indicate that the species may have lived in more active lifestyle in low-oxygen environments. In fact, the gills resemble the same structure that horseshoe crabs possess, which is called the opisthosoma. "That's not to say that horseshoe crabs and radiodonts are especially closely related, but it's instead an example of convergent evolution," said paleontologist Greg Edgecombe, per the U.K. Natural History Museum. Greta Cross is a national trending reporter at USA TODAY. Story idea? Email her at gcross@ This article originally appeared on USA TODAY: 'Sea moth': Scientists discover 3-eyed sea creature, Mosura fentoni
USA Today
15-05-2025
- Science
- USA Today
Meet the 'sea moth,' a three-eyed sea creature from 500+ million years ago
Meet the 'sea moth,' a three-eyed sea creature from 500+ million years ago The Mosura fentoni, or "sea moth," may have used its third, median eye to detect light and move around its environment. Show Caption Hide Caption Strange and bizarre creature from 506 million years ago discovered A three-eyed predator 'sea moth' that lived 506 million years ago has been discovered in Canada. Scientists have discovered a three-eyed "sea moth" that dates back more than half a billion years ago. Paleontologists Joseph Moysiuk and Jean-Bernard Caron published a study an Wednesday, May 14 that introduces their findings of Mosura fentoni, a new type of radiodont that existed more than 500 million years ago. The "sea moth"-like species caught researchers' attention because of its third, median eye. Scientists named the newly-discovered species "Mosura fentoni," after the fictional Japanese monster kaiju, also known as "Mothra," for its moth-like appearance, the study states. Here's what to know about the newly-discovered deep sea creature. What is Mosura fentoni, the 'sea moth'? The newly-discovered Mosura fentoni specimen is only about 15 to 61 millimeters long (0.6 to 2.4 inches). The "sea moth" features a short head; small, rounded exoskeleton; three prominent eyes; appendages; large swimming flaps; and densely-packed gills, according to the study. The Mosura fentoni lived during the Cambrian Explosion, which began about 541 million years ago. The Mosura fentoni was a radiodont, a type of arthropod that lived between 520 to 400 million years ago, according to the United Kingdom's Natural History Museum. A popularly known radiodont is Anomalocaris, thought to be one of the first apex predators. Paleontologists believe Mosura fentoni hunted small prey, like shrimp, to avoid competing with other radiodonts in its ecosystem, according to the U.K. Natural History Museum. Mosura fentoni would have used rows of paddle-like fins to glide through the ocean and then use hook-like segments of its feeding appendages to grab small pray and move them through its mouth. Why did Mosura fentoni have a third eye? While paleontologists are still learning why Mosura fentoni had a third eye, researchers believe the eye may have been used to detect light and the seascape it moved through. Perhaps Mosura fentoni's median eye was similar to that of a dragonfly's extra eyes (yes, dragonflies have five eyes), used to orient themselves during high-speed hunts, according to the U.K. Natural History Museum. 'Sea moth' poses new features from other radiodonts A feature of the specimen that has particularly intrigued researchers is its dark, reflective patches, which are called "tonguelettes." Though these structures have been interpreted differently over the years, in Mosura fentoni, researchers believe they suggest structures of an open circulatory system, according to the museum. This means that the Mosura fentoni would have pumped a blood-like substance called haemolymph through a series of body cavities. "Their identity has been controversial, but the well-preserved (body cavities) in Mosura help us to interpret similar, but less clear features that we've seen before in other fossils," Moysiuk told the U.K. museum. "It turns out that preservation of these structures is widespread, confirming the ancient origin of this type of circulatory system." The Mosura fentoni's densely-packed gills also vary from other radiodonts that researchers have studied. These gills indicate that the species may have lived in more active lifestyle in low-oxygen environments. In fact, the gills resemble the same structure that horseshoe crabs possess, which is called the opisthosoma. "That's not to say that horseshoe crabs and radiodonts are especially closely related, but it's instead an example of convergent evolution," said paleontologist Greg Edgecombe, per the U.K. Natural History Museum. Greta Cross is a national trending reporter at USA TODAY. Story idea? Email her at gcross@
Daily Mirror
15-05-2025
- Science
- Daily Mirror
Prehistoric sea monster with three eyes discovered but has another odd feature
A three-eyed prehistoric sea monster known as Mosura fentoni was recently discovered in Canada and lived in the world's oceans some 500 million years ago with another odd feature A bizarre sea creature which hunted prey more than 500 million years ago had three eyes, and another unusual feature. Fossils containing Mosura fentoni were recently discovered in Canada and were arthropods, which in modern times became the likes of spiders, scorpions and crabs. They arrived as part of what scientists known as the Cambrian Explosion and boasts a third eye - no doubt helpful for when the small crustacean was hunting in the Earth's oceans of the time. Despite being named after Mothra, a giant-moth-like creature which fought Godzilla in films, it was around the size of a person's finger. However, despite having a third eye its most odd feature was having a body that was divided into as many as 26 segments - far earlier than they believed segmentation appeared in life. Dr Jean-Bernard Caron, the co-author of the research, says the new species can help researchers to understand how arthropods have evolved. He said: 'Radiodonts were the first group of arthropods to branch out in the evolutionary tree, so they provide key insight into ancestral traits for the entire group. 'The new species emphasizes that these early arthropods were already surprisingly diverse and were adapting in a comparable way to their distant modern relatives.' Experts say Mosura would have pursued its prey using rows of paddle-like fins along its sides and helped it glide through the ocean. Hook-like segments on its feeding appendages would have been able to grab prey and move them to its mouth. Known as radiodonts, they were a group of arthropods which lived for more than 100 million years between 520 and 400 million years ago. Until fairly recently, only a few species of these animals were known. Expert Dr Greg Edgecombe added: 'After a huge flurry of research, we now know of 38 named species of radiodonts from all over the world. They're stem-group arthropods, meaning that they branched off before the most recent common ancestor of the living group. 'So, radiodonts are not members of any of the major groups of today's arthropods. What makes them interesting is their distinct body plan, which shares some of the characteristics of living arthropods but not others. They have compound eyes, for example, but only just the one pair of jointed appendages. 'Until Mosura, all radiodonts have organised their body in a similar way. They've all had a similar head composition, a neck composed of a few segments, and then a body with swimming flaps that ends with a crustacean-like tail fan. 'The narrow, gill-dense segments of Mosura have been compared to a similar structure in horseshoe crabs known as the opisthosoma. That's not to say that horseshoe crabs and radiodonts are especially closely related, but it's instead an example of convergent evolution.'
Yahoo
25-02-2025
- Science
- Yahoo
Can humans really extinguish all life on Earth? It's complicated
You've heard it before: we're well into the sixth mass extinction of life on earth. Only this time, unlike the other five big ones, humans are overwhelmingly the killers responsible. As we continue to set the world on fire, regardless of a certain administration's attempts to pretend it's not happening, scientists warn we are in unprecedented territory that could result in a whole bunch of death, especially for impoverished people in the global south and the ongoing "biological holocaust" happening to nature. But are we truly the masters of our domain, this little blue planet? And could we really end all life on Earth? What if we dropped every nuke at once? Would that get every bug, including roaches and bacteria? 'No way, no chance, no prayer — there's not the slightest possibility that we could wipe out all of life,' said Dr. David Jablonski, professor of geophysical sciences at the University of Chicago. "I mean, there are microbes living under glaciers and a kilometre down in the crust [of the Earth.]" When I feel despair, and a kind of profound bottomless sadness, at the unchecked destruction of millions and millions of years of irreplaceable biodiversity going on right now, I take a little comfort imagining that from the smoking ruins of whatever remains once we've finally, foolishly removed the last biological underpinnings that keep us alive, complex life will likely re-emerge. It's done so after at least five other mass extinctions, all long before humans arrived on the scene. And it will do so after the Anthropocene extinction, which is being caused by human activities. Our downward spiral notably includes the spread of invasive species; overexploitation of species; habitat modification, fragmentation and destruction; pollution; and, of course, climate change. Though Jablonski is more bullish on the survival prospects of unicellular life, there is some comfort for the multicellular among us too. Jablonski studies patterns of evolution, including the ways in which life rebounds after mass extinctions. It's been observed that following these mega-death events, not only is there not nothing, but in fact in the years — actually, the hundreds of thousands or millions of years, because we're talking geological time here — following a mass extinction, there is often an explosion of biodiversity, with surviving species evolving new branches on their evolutionary trees. It's not always an absolutely gobsmacking profusion of uncontrollably bizarre life, as occurred with what's aptly called the Cambrian Explosion, a period about 540 million years ago when evolution got extremely creative. Nature began evolving entirely new body plans, with innovations like hard shells and backbones that have even survived up to today, and the ancestors of pretty much all the major groups (phyla) of animals. Of course, plenty of branches on the evolutionary tree fizzled out too, which is why creatures like Hallucigenia, a worm bug with spikes on its back and tentacles and legs on its front, are no longer with us. We don't really know why the Cambrian was so exceptionally diverse. The ancestors of groups that diversified so much during the Cambrian existed before. But it wasn't till the Precambrian extinction 544 million years ago that they burst through their previous limits, generating new species that found new ways to live. Sometimes, as with mammals after the non-avian dinosaurs died out, the diversity that occurs post-extinction isn't so much a question of numbers of species but of a group diversifying functionally (expanding the range of what new species in the group can do) or morphologically (expanding their possibilities of size or physical form) into new ecological niches. This can result in many things growing startlingly big, for example. It's almost as if the mass extinction process were clearing the way for this wild flourishing of new life you've planted. because, explained Jablonski, the patterns of diversity in the life we see after extinction do not relate to the patterns of diversity that existed before that extinction. After the Cretaceous–Paleogene extinction that killed off most of the dinosaurs, for example, the top carnivores for a while were not the mammals that ultimately replaced them but giant, flightless birds known as "terror birds." Also known as Phorusrhacids, these nightmare creatures grew up to ten feet tall and weighed 200 lb, and they could hunt you down by chasing you across the South American or Antarctic plains with their great hooked beaks at a pace of 30 mph. The terror birds, which out-competed the mammals in occupying this particular ecological niche, may even have driven mammalian predators to take to the forests instead. The point here is that if we kill off all the animals in hopes of sparking some glorious diversification as life rebounds in a few millions years' time, there's no guarantee of what we're going to get. "There's no way our world looks the way it did in the Mesozoic, even without the fact that we no longer have T-Rex and Triceratops. It's also that in the oceans, the lineage, the modes of life that were most diverse no longer have the most species in them," Jablonski told Salon. "It's so different from the picture that you sometimes get" of post-extinction rebound, where it was seen as a simple recovery of populations, "essentially just recreating the vanished world," Jablonski went on. By contrast, the modes of life (the different ways organisms adapt to their environment) that exist seem to rebound pretty well, but entirely different types of organisms may occupy them (a terror bird, for example, when you were hoping for a cheetah.) And that's important if we were thinking that, given that life's so robust and resilient, we might as well go for broke, destroy everything we can, and enjoy all the new life in a few million years' time. "The bottom line is that the selectivity of extinction and modes of life has nothing whatsoever to do with the convenience or well-being of humans. The things that survive and probably diversify will of course be the rats and the ragweed and the cockroaches, and so that probably is going to be the shape of the world in the future, unless some really concerted work is done to ameliorate some of the most extreme forces," Jablonski said, noting that it isn't even an issue of having the right numbers of species, but the right modes of life. If you were playing God, for example, you'd want to stash as many pollinators in your ark as you can, and as many plant species that are really good at storing carbon as you can. "There's no reason whatsoever that the survivors or the rebounders will do that for us unless we actually engineer that," Jablonski said, referring not to bioengineering but to the urgent task of carefully designing nature reserves and migration corridors to protect exploited species at risk from human pressures by conserving large enough areas that the species you prioritize can survive in, taking into account their ability to get there and the expected climate. "I was talking to someone just last week who was like, 'Oh yeah, cockroaches have survived every extinction event, and they'll be here after everything else dies'. And I'm like, 'Well no, not really'," Dr. Dominic Evangelista, an evolutionary biologist and principal investigator at The Roach Brain Lab at the University of Illinois Urbana-Champaign, told Salon in a video interview. Evangelista has found that cockroaches, of which there are some 7,000 species, only ten of which are city pests, are younger than previously believed. In the past, fossils of insects that were likely ancestors of both praying mantises and cockroaches (and termites, which are a subgroup of cockroach) called roachoids may have been incorrectly identified as roaches. Now it is believed that the earliest real cockroach fossil is just 125 million years old, meaning it lived well after the Permian-Triassic extinction, when some 90% of all species on Earth were wiped out, and after the Triassic-Jurassic extinction that cleared the way for the dinosaurs. The Cretaceous period was the time of the cockroaches, and they thus survived just one of the five mass extinctions that occurred before the one we're living in right now. Nor are they particularly resistant to radiation compared to most other insects. Not such tough guys after all. So are humans capable of driving Earth's cockroaches to absolute extinction? "One hundred percent," Evangelista told Salon. "And we have already seen cockroaches go extinct." The biggest danger to these supposedly hardy creatures is habitat loss in the tropics, where species diversity is extreme and where the thousands of different species of cockroach tend to specialize, so that different species will be endemic to different areas, meaning that they are found in that region and nowhere else. High levels of endemism make it extremely easy to extinguish a species from existence: burn down one lush, lavishly biodiverse forest and you may have wiped out thousands of species so specialized they live nowhere else and may be unknown to science. Burn enough forest and you risk driving not one, but all 7,000 species to extinction. In one prescient example, a particular cave in Guinea, West Africa that once sheltered the Simandoa cave roach (Simandoa conserfariam) was destroyed a bit more than a decade ago in a bauxite mining operation. With it went the cave roach, which is now extinct in the wild. That insect, which exists now as a relic in captivity and can be purchased on the internet by hobbyists, is a beautiful creature with rust-coloured legs and a black body, the prothorax outlined in white, concealing a striking black-and-white striped abdomen. Entire species may vanish before humans have even had the chance to christen them with a name, let alone to understand their behavior, their role in the ecosystem, or (to center our petty human lives again) their potential to, say, fight antibiotic resistant bacteria, or teach robots how to walk. Given that scientists keep finding new species of cockroach, even in highly-sampled areas, that seems more than likely: Evangelista's lab is at work describing species unknown to science from Guyana, an area of pristine and biodiverse forests that are relatively understudied, as well as from neighboring French Guiana, already known as a cockroach diversity hot spot in South America. So, we can kill cockroaches after all. And in fact, we're doing it all the time. Evangelista said it's hard to prove that something has gone extinct if you didn't know it existed to begin with. "Personally, I am certain that not only have humans caused some cockroaches to go extinct, but we've probably caused hundreds or maybe thousands of cockroaches to go extinct, and we don't even know about it," Evangelista said. Getting rid of roaches is one thing — but are humans really so powerful as to destroy all life on the third rock from the Sun? Perhaps it would help to consider what, other than humans or divine intervention, might kill everything on Earth. The tiny organisms Jablonski mentioned living within the Earth's crust or under glaciers are extremophiles, tiny organisms that live and thrive in the most extreme environments we can imagine (a rather human-centric definition, mind.) There are extremophiles that can thrive under the extraordinarily high pressure at the bottom of the Mariana Trench; in environments more alkaline than pH 11 and more acidic than pH 0.06 (which are both high ends of the spectrum); at up to 252° F in the Earth's crust or in scorching hydrothermal vents; in super-dry, super-salty, or super-cold environments; or under the effects of ionizing radiation. Boiling off all the world's oceans seems to be THE initial outcome to worry about on the way to total extinction, at least according to a study from Oxford University titled "The resilience of life to astrophysical events." Researchers David Sloan, Rafael Alves Batista, and Avi Loeb considered the various things that could cause such a calamity in reference to the impact that could be expected upon the tardigrade, a particularly hardy, bizarrely cute micro-animal also known as a water bear. Technically, tardigrades are not extremophiles, because while they can survive conditions that would kill anything else, that doesn't mean they thrive in them. But they're pretty darn tough. The easiest way to kill off the tardigrades, the researchers argue, would be to sterilize the entire planet, adding 5.6 × 1026 J of energy to make the oceans boil off. It would require even more energy to remove the Earth's atmosphere, and you'd also need more radiation to kill a tardigrade hiding deep enough under the sea. Only a large asteroid impact, supernova explosion, or deadly gamma-ray bursts (GRBs) offer much chance of evaporating the oceans. The researchers estimate the likelihood of the various events serious enough to do this at a probability of less than 10−7 per billion years. It's unlikely that there's anything we puny humans can do that would have the impact of these extremely extreme events, which, as Sloan, Batista and Loeb concluded, were unlikely to finish off the water bear anytime soon. By soon, they mean any time before the sun engulfs us all, which will happen sometime in the next five billion years. Our star dying is an event, the authors say, that even tardigrades are not going to pull through. Luckily for them, by the time that happens the tardigrades may well have hitched a ride into outer space and traveled well beyond the sun's overheated grasp. We, on the other hand, will be long gone by then, shriveled by some far more minor cataclysm like the fragile little primates we are. So if tardigrades (never mind hardier extremophiles) are likely to survive gamma-rays, asteroid impacts and exploding supernovae, it seems highly likely that we're not going to be the ones who strike the fatal blow to all life on Earth. On the other hand, we're trying really hard.
