extinction

From evolutionary biologist Richard O. Prum at the New York Times: Are These Birds Too Sexy to Survive? Natural selection can’t explain this. Wow. Careers have been wrecked over such departures from dogma. Most biologists believe that these mechanisms always work in concert — that sex appeal is the sign of an objectively better mate, one with better genes or in better condition. But the wing songs of the club-winged manakin provide new insights that contradict this conventional wisdom. Instead of ensuring that organisms are on an inexorable path to self-improvement, mate choice can drive a species into what I call maladaptive decadence — a decline in survival and fecundity of the entire species. It may even lead to extinction. Read More ›

From Hank Campbell at Science 2.0: Colony Collapse Disorder, the belief that honeybees, an important pollinator, are being killed off in droves, has been good for environmental fundraising but hasn’t had a scientific foundation. … Nonetheless, it has persisted for 10 years despite data showing that periodic die-offs in bees are as common, and therefore predictable, as solar cycles and California droughts. From the time that records of bees were formally kept, there were reports of mass die-offs without explanation, a thousand years before pesticides even existed. More. Indeed. There are even superstitions connected with the humanly unpredictable ways of bees, including sudden departures and mass die-offs. One problem is that extinction and serious declines feel like Armageddon and many Read More ›

From Mike Wehner at Yahoo News: Multiple reports of Tasmanian Tiger sightings are starting to flow in from everyday citizens in Australia. Several people have recently claimed they’ve spotted the animal… The marsupial Thylacine, believed extinct, is really much more like a wolf than a tiger, in appearance and ecological role. Australians have occasionally claimed to have spotted the dog-like animals over the years, but the sightings were typically rare and attributed to nothing more than misidentification. That’s all changed now, as several “plausible sightings” are beginning to give life to the theory that the animal never actually went extinct at all. Now, scientists in Queensland, Australia, are taking action in the hopes of actually finding evidence that the Tiger Read More ›

Challenges fundamentals of echinoderm evolution. From ScienceDaily: Echinoderms are among the marine invertebrates that suffered the most severe losses at the end-Permian extinction. At least that was the consensus until a team of European paleontologists — Ben Thuy, Hans Hagdorn, and Andy S. Gale — cast a critical eye on some poorly studied Triassic echinoderm fossils. The fossils turned out to belong to groups that supposedly went extinct by the end of the Paleozoic. Some ancient echinoids, ophiuroids, and asteroids had slipped the bottleneck and coexisted with the ancestors of modern-day sea urchins, brittle stars, sand dollars, and relatives, for many millions of years. These echinoderm hangovers occurred almost worldwide and had spread into a wide range of paleo-environments by Read More ›

Nick Stockton asks, at Wired, why didn’t the ice ages that began at 800,000 ago just remain? What reversed the cooling trend? A new study, published today in Nature Geoscience, has a hypothesis what that something was: plants. Or, more specifically, a complicated process in which plants wear down certain kinds of rocks, and how those rocks remove carbon dioxide from the atmosphere as they wear down—leaving just enough CO2 out there to trap solar warmth, and gradually bring summer back. More. Most ecology on the planet actually depends on plants. Everything seems organized around them, including temperatures. See also: How plants see, hear, smell, and respond without animal sense organs Follow UD News at Twitter!

From Brian Switek at Nature: A study1 published 2 March in PLOS Genetics gives a rare insight into how genomes change as a species dies out. Towards the end of the last Ice Age, around 11,700 years ago, woolly mammoths ranged through Siberia and into the colder stretches of North America. But by about 4,000 years ago, mainland mammoths had died out and only 300 remained on Wrangel Island off the Siberian coast. In order to examine this disappearance at the genetic level, biologists Rebekah Rogers and Montgomery Slatkin at the University of California, Berkeley, compared the complete genome of a mainland mammoth (Mammuthus primigenius) that lived about 45,000 years ago with that of a Wrangel Island mammoth from about Read More ›

Except where dinosaurs or media-friendly modern species are in play, extinction barely rates a yawn. But here is an interesting item by Veronika Meduna at New Scientist, on a plan to return an ecosystem to a previous time: We are inside the old water reservoir for New Zealand’s capital, Wellington. Over the past two decades, it has undergone an extraordinary transformation, from urban utility to ecological haven. During the day, large forest parrots called kaka swoop over tuatara, the only survivors of a prehistoric group of reptiles. Night-time visitors have a good chance of crossing paths with a little spotted kiwi. Hihi – small black, white and yellow birds that had once disappeared from New Zealand’s main islands – are Read More ›

After the asteroid hit. The extinction of the dinosaurs is, in certain ways, the pop science equivalent of the falls of great houses in ancient literature. It’s  fascinating and it accommodates dozens of plausible explanations and hundreds of possible ones. Good for business. From ScienceDaily: “It became cold, I mean, really cold,” says Brugger. Global annual mean surface air temperature dropped by at least 26 degrees Celsius. The dinosaurs were used to living in a lush climate. After the asteroid’s impact, the annual average temperature was below freezing point for about 3 years. Evidently, the ice caps expanded. Even in the tropics, annual mean temperatures went from 27 degrees to mere 5 degrees. “The long-term cooling caused by the sulfate Read More ›

From ScienceDaily: Amphibians which have a toxic defense against predators — such as the iconic poison dart frogs — have a much higher risk of extinction than species which use other types of defense mechanisms, research shows. The key finding of this study is that poisonous species are 60% more likely to be threatened than species without chemical defenses. … That might seem counterintuitive. Dr Arbuckle previously suggested three main possibilities to explain higher extinction rates in toxic amphibians, and figuring out which of these have been important are the focus of another study. The different ideas are: Costly chemical hypothesis: Chemical defense is energetically costly; Marginal habitats hypothesis: Chemical defense allows shifts to ‘marginal’ (low carrying capacity) habitats, which Read More ›

From Stephanie Pappas at LiveScience: Stephen Hawking thinks humanity has only 1,000 years left of survival on Earth and that our species needs to colonize other planets. The famed physicist made the statement in a speech at Oxford University Union, in which he promoted the goal of searching for and colonizing Earth-like exoplanets. Developing the technology to allow humans to travel to and live on faraway alien worlds is a challenge, to say the least. But is Hawking right that humanity has only 1,000 years to figure it out? The dangers Hawking cited — from climate change, to nuclear weapons, to genetically engineered viruses — could indeed pose existential threats to our species, experts say, but predicting a millennium into Read More ›

According to Living Planet. From Nisha Gaind at Nature: The populations of Earth’s wild mammals, birds, amphibians, fish and other vertebrates declined by more than half between 1970 and 2012, according to a report from environmental charity WWF and the Zoological Society of London (ZSL). Activities such as deforestation, poaching and human-induced climate change are in large part to blame for the decline. If the trend continues, then by 2020 the world will have lost two-thirds of its vertebrate biodiversity, according to the Living Planet Report 2016. “There is no sign yet that this rate will decrease,” the report says. More. Apart from issues around data bias covered in Gaind’s article, a question remains: When we try to save a Read More ›

Here: Q: What is the Voluntary Human Extinction Movement?VHEMT (pronounced vehement) is a movement not an organization. It’s a movement advanced by people who care about life on planet Earth. We’re not just a bunch of misanthropes and anti-social, Malthusian misfits, taking morbid delight whenever disaster strikes humans. Nothing could be farther from the truth. Voluntary human extinction is the humanitarian alternative to human disasters. … When every human chooses to stop breeding, Earth’s biosphere will be allowed to return to its former glory, and all remaining creatures will be free to live, die, evolve (if they believe in evolution), and will perhaps pass away, as so many of Nature’s “experiments” have done throughout the eons. It’s going to take Read More ›

“Greatly exaggerated,” as Mark Twain put it, when informed of media accounts of his own death. From Maria Gallucci at Mashable: The good news is, relatively speaking, that the rest of the 1,400-mile-long coral reef is alive — severely threatened, yes, but not yet dead. A widely shared “obituary” in Outside magazine last week inaccurately claimed that all of the Great Barrier Reef “passed away in 2016” after a brief battle with global warming and ocean acidification. … Huffington Post and other outlets soon set the record straight, clarifying that while most of the Australian reef is in serious trouble, we still have a fighting chance to rescue it from its deathbed. More. It reminds some of us here of Read More ›

No, says paleontologist and evolutionary biologist Steven Stanley of the University of Hawaii, arguing that the extinction rate was closer to 81% than 96%. From Phys.org: The Permian-Triassic mass extinction lasted for approximately 60,000 years, and was undoubtedly a tough time for the creatures that lived back then—prior research has suggested that there was an unusually large amount of volcanic activity and also possibly multiple large asteroid impacts, which together caused the planet to warm, and also resulted in an increase in ocean acidification—the conditions were so harsh that many species on land and in the sea went extinct. But, Stanley argues, it was not bad enough to wipe out most marine life entirely, as some have suggested. He points Read More ›

From Ewen Callaway at Nature: Scientists had assumed from fossil evidence that an ancient predecessor called the straight-tusked elephant (Paleoloxodon antiquus), which lived in European forests until around 100,000 years ago, was a close relative of Asian elephants. In fact, this ancient species is most closely related to African forest elephants, a genetic analysis now reveals. Even more surprising, living forest elephants in the Congo Basin are closer kin to the extinct species than they are to today’s African savannah-dwellers. And, together with newly announced genomes from ancient mammoths, the analysis also reveals that many different elephant and mammoth species interbred in the past. More. This is happening so often now that there is clearly something wrong with the way Read More ›