JOIN USPrehistoric puzzle
How the plesiosaurs swam
Millions of years ago, leviathans known as plesiosaurs prowled the oceans. With their long necks and barrelled bodies, these marine reptiles had four long flippers. The two nearly identical pairs of aquatic limbs have long puzzled palaeontologists. “Having four big flippers like that is rather strange,” said Luke Muscutt, a biomechanist and postdoctoral researcher at the University of Southampton, UK.
Luke spent his thesis decoding how the plesiosaur paddled, which he said is unlike any other living vertebrate that swims in the ocean. Fish and sharks swim by swinging their tails side to side, and whales and dolphins swing theirs up and down. Even other animals with flippers like sea lions and sea turtles do not swim with all four flippers, he said.
His study in the journal Proceedings of the Royal Society B provides further evidence that the hind flippers were key to the plesiosaur’s underwater moves, and were not just limbs used for steering. “Plesiosaurs definitely used all four flippers for propulsion and that made them more efficient and effective swimmers,” said Luke. The findings, he said, could help settle the long-running debate on how the plesiosaur swam. They could also contribute to future designs for underwater drones or submersibles.
Ingenious Methods
How Neanderthals made glue
Neanderthals seem stuck with unflattering reputations. The entire species of early human ancestors has long been reduced to a pejorative for describing someone who isn’t very bright, despite growing evidence of the sophistication of Homo neanderthalensis. And recent research suggests another overlooked mark of their ingenuity: they made the first glues in the form of tar. The tar was distilled from the bark of birch trees some 2,00,000 years ago, and seemed to have been used for hafting, or attaching handles to stone tools and weapons. But scientists did not know how Neanderthals produced the dark, sticky substance. Now, in a study that was recently published in the journal Scientific Reports, a team of archaeologists has used materials available during prehistoric times to demonstrate three possible ways Neanderthals could have deliberately made tar. While the study does not prove that Neanderthals used any of these methods, it aims to demonstrate that they had access to the ingredients and means to produce tar. “There’s this popular perspective of Neanderthals as being these simple cave men and slow-type brutes,” said Paul Kozowyk, a graduate student at Leiden University in the Netherlands and lead author of the study. “This tar production, and its use for hafting, is evidence that this isn’t really true.”
Going green
Natural dyes from plant extracts
Ever wondered what happened to all our centuries-old learning of using natural dyes on abric like cotton, silk and wool? With synthetic dyes that are non-biodegradable, carcinogenic and pollute our waters, we are doing more harm than good to ourselves.
A new study by researchers at the University of Delhi has proposed efficient techniques to extract natural dye from plant-based sources like roots of turmeric, fruits of harda (myrobalan), petals of safflower and roots of barberry.
Once extracted, the technique proposes to add mordants such as alum, copper sulphate and ferrous sulphate to obtain a rainbow of natural colours that could then be used to colour your favourite piece of garment. Going green, literally!
Animals at risk
Size matters for extinction
Animals in the Goldilocks zone — neither too big, nor too small, but just the right size — face a lower risk of extinction than do those on both ends of the scale, according to an extensive global analysis. Reporting in the Proceedings of the National Academy of Sciences, researchers who determined body masses for thousands of vertebrate animal species showed that the largest and smallest species face a greater risk of extinction than do mid-sized animals. Researchers looked at more than 27,000 vertebrate animal species, including birds, reptiles, amphibians, bony fishes, cartilaginous fishes and mammals. Disproportionate losses at the large and small ends of the scale raise the likelihood of significant changes to the way natural ecosystems function in forests, grasslands, oceans and even rivers and streams — “the living architecture of the planet,” the researchers wrote.
Biocontrol
Rearing predators to control cotton pests
Cotton pests have been the cause of decreasing cotton yields in the country. Despite several attempts to control these insects, their numbers remain unaffected. Rhynocoris fuscipes is a species of insect that are known to be the natural predators of many cotton pests. Now, scientists from St Xavier’s College, University of Florida and US Horticultural Research laboratory have proposed rearing Rhynocoris fuscipes in microenvironmental cages and using them as predators to control cotton pests. Their study showed that, when reared, these predators are far more effective at biocontrol of cotton pests, than when they are allowed to do so naturally. The study also showed that the technique does not affect any other insects in the cotton agroecosystem.
Documentary
Dangers of pesticides
The Slow Poisoning of India, directed by Ramesh Menon, depicts the effects of widespread pesticide use on rural people and local ecology. It narrates startling case studies like the endosulfan tragedy in the Kasaragod district of Kerala. It also discusses the health impacts that pesticides have had in other parts of India, and how sustainable farming methods are now gaining popularity.
The documentary can be watched at www.bit.ly/2wbi4My.
Documentary
The Slow Poisoning of India
The Slow Poisoning of India is a 26-minute documentary that deals with the dangers of excessive use of pesticide in agriculture. India is one of the largest users of pesticide in Asia and also one of the largest manufactures. The toxins have entered into the food chain and into our breakfast, lunch and dinner. The documentary showcases startling case studies from Kerala where villagers in Kasaragod district are paying a heavy price as it has been exposed to pesticide spraying for many years. It talks of the health impacts in other parts of India and also on how the magic of the green revolution in Punjab is fading as land and water bodies have been poisoned. But some farmers are bouncing back into better practices, and this is a silver lining shown towards the end.