(Visited 576 times, 1 visits today)FacebookTwitterPinterestSave分享0 Bugs so small you could step on them, but if we were their size, we could never do what they do.G-ForceThis Beetle Can Withstand 40 Times More G-Force Than a Fighter Pilot (National Geographic). Ever watched a click beetle? Maybe not since you were a kid. These amazing beetles can leap up into the air and right themselves when they have fallen on their backs. Liz Langley writes, “Click beetles are among nature’s many unsung acrobats with clever strategies for escape.” There are 900 species of click beetles that use this trick. Here’s how it works:When threatened, the insect will contract a hinge that holds together two segments of its body, says Gal Ribak of Tel-Aviv University’s Biomechanics of Animal Locomotion Laboratory.Releasing that elastic energy causes an audible click and accelerates the beetles into the air at 380 times the force of gravity—leaving predators mystified.Langley includes accounts of other animals that are “aerialists that perform amazing airborne feats—sometimes with no feets at all.” A Moroccan spider named flic flac, for instance, can cartwheel away from danger, even going uphill. And a spider in Trinidad can whirl in circles so fast, it looks like a blur to the human eye. The article briefly mentions birds that walk down tree trunks, flying rays, pirouetting sharks, and has a 32-photo gallery of various leaping animals, including birds, fish and mammals.Magnetic NavigationNavigating with the sixth sense: desert ants sense Earth’s magnetic field (University of Würzburg). It’s unbelievable enough that salmon and sea turtles could navigate by the earth’s magnetic field, but ants? Such tiny insects; how do they do it? Researchers at the University of Würzburg, using controlled magnetic conditions, found that they indeed can. The details can be read in an open-access paper in Current Biology. The press release says,Desert ants (Cataglyphis) spend the first weeks of their life exclusively in their dark underground nest. For around four weeks, they nurse the queen and the brood, dig tunnels, build chambers or tidy up. At some point, they leave the nest to start their outdoor career, working as foragers until their death.Before an ant sets out to forage, it has to calibrate its navigational system, however. For this purpose, the insects exhibit a rather peculiar behaviour during two to three days: They perform so-called learning walks to explore the vicinity of the nest entrance and frequently turn about their vertical body axes while doing so. High-speed video recordings show that the ants stop repeatedly during these pirouetting motions. What is special about the longest of these stopping phases is that at this moment the ants always look back precisely to the nest entrance, although they are unable to see the tiny hole in the ground.Researchers from the Biocenter of the University of Würzburg have now made the surprising discovery that the desert ant uses the Earth’s magnetic field as orientation cue during these calibration trips. This ability had been previously unknown for desert ants.Dragonfly (Corel Professional Photos)AerogelWorld’s oldest insect inspires a new generation of aerogels (Newcastle University). When dragonflies complete their metamorphosis, their wings come out out like jelly, but within minutes they expand and become completely dry. Inspired by what they saw, the wizards at Newcastle University designed an aerogel that mimics the dragonfly’s secret. They tell how they did it, but more interesting are the dragonflies themselves. If they evolved, like this article claims, it means that some of the most advanced insect flyers just popped into existence without ancestors.“These ancient insects were around long before the dinosaurs evolved,“ explains Dejan Kulijer, from the National Museum of Bosnia and Herzegovina.“They are one of the oldest insect groups to take flight and include the largest insect that ever lived – the Griffenfly – that had a wingspan of more than 70 cm” [28 inches].Their wings are a porous, layered structure similar to an aerogel and are so strong and light they can carry the insect up to 30 miles in an hour.“A dragonfly’s wings are an ultralight aerogel – making up less than 2% of the insect’s total body weight – and yet they are so strong they can carry the insect thousands of miles across oceans and between continents,” says Dr Šiller, who worked on the research together with colleagues from Newcastle University, Durham University and Limerick University, Ireland, as well as experts from the National Museum of Bosnia and Herzegovina.Jumps and LeapsWhy a robot can’t yet outjump a flea: How small creatures generate world’s fastest snaps, jumps and punches (Duke University Today). No robot designer has been able to imitate the mighty leap of the tiny flea. These insects jump so fast and far, they seem to vanish from sight. The opening of this fun article shows a flea jumping in slow motion, but mentions that it’s not the only champion in the animal olympics. Here are more challengers for robot designers:Take the smashing mantis shrimp, a small crustacean not much bigger than a thumb. Its hammer-like mouthparts can repeatedly deliver 69-mile-per-hour wallops more than 100 times faster than the blink of an eye to break open hard snail shells.Or the unassuming trap-jaw ant: In a zero-to-60 matchup, even the fastest dragster would have little chance against its snapping mandibles, which reach speeds of more than 140 miles per hour in less than a millisecond to nab their prey.One of the fastest accelerations known on Earth is the hydra’s sting. These soft-bodied aquatic creatures defend themselves with help from capsules along their tentacles that act like pressurized balloons. When triggered, they fire a barrage of microscopic poison spears that briefly accelerate 100 times faster than a bullet.Another video clip in the article shows a trap-jaw ant launching itself into the air with its mandible. It had to be filmed at 3,000 frames per second to see the action. Also praised in the article are the chameleon, the Venus flytrap, and the froghopper:A short-legged insect called the froghopper, for example, has a bow-like structure called the pleural arch that acts like a spring. Latch-like protrusions on their legs control its release, allowing them to leap more than 100 times their body length despite their short legs. A person with that much power could jump nearly two football fields.Each of these feats, the article explains, doesn’t require muscle action. They work with spring-loaded parts that fire like a taut bowstring. The paper in Science Magazine delves into “The principles of cascading power limits in small, fast biological and engineered systems,” describing a new model designed at Duke to explain the power requirements and specifications for such powerful leaps. The press release explains why robot makers can’t yet match these natural achievements:The model has major implications for engineers. It suggests that robots can’t yet outjump a flea in part because such quick, repeatable movements require components to be exquisitely fine-tuned to each other.Don’t tell the Discovery Institute. Incidentally, a new species of fossil dragonfly was named after the Revolutionary, Dr Michael Behe (Evolution News).The wonders of nature inspire kids. The wonders of nature inspire adults. The wonders of nature inspire scientists and engineers. Anyone left out? There is one thing that reduces inspiration, like poking a hole in a hot air balloon. It’s the idea that these wonders just happened by chance. Darwinian hot air is not sufficient to substitute for the fires of inspiration lit by the wonders of nature. Keep those Darwinists with their spears away from the big, beautiful balloon celebration.Credit: J.B. Greene
10 December 2013 Nelson Mandela was a “giant for justice”, United Nations Secretary-General Ban Ki-moon said during a visit to the Nelson Mandela Foundation in Johannesburg on Monday. Ban, who was due to join some 70 heads of state at the memorial service for Mandela at Johannesburg’s FNB Stadium on Tuesday, said Mandela’s “principled stand in defense of the fundamental equality of all human beings was decisive in dismantling the system of apartheid. “His remarkable compassion upon his release from prison after 27 years set South Africa immediately on a path of dialogue and reconciliation,” Ban said. “He was a giant for justice, equality and human rights.” Mandela died last Thursday after a long battle with a lung infection. The late human rights lawyer, prisoner of conscience, international peacemaker and first democratically elected president of South Africa was 95. Ban said Mandela was more than one of the world’s greatest leaders. “He was a teacher, and he taught and practised by example.” Recalling the first time he met Mandela, during an official visit to South Africa in February 2009, Ban said he had “wanted to say a few words of thanks for what he was doing for humanity. [Mandela’s] response has stayed with me ever since. He said: ‘Well, it’s not only me, there were hundreds and hundreds of known and unknown people who fought for the same cause. “I was so deeply moved and touched. What he said has guided me ever since,” Ban said. “The people of South Africa and the whole world have lost a hero. May Nelson Mandela rest in peace.” The secretary-general also visited Mandela’s residence, where he offered his condolences to the former president’s family. SAinfo reporter
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