My Science School

The world has woken up to the threats posed by plastic-especially the single-use ones - to the environment and marine life in particular. In the recent decades, scientists have also come to recognise the dangers of microplastics, which are extremely small pieces of plastic debris resulting from the breakdown of plastic products. Now, they have sounded alarm over another tiny, yet hazardous plastic items called nurdles. Depending on their density, nurdles can either float to the surface of the water or sink below the surface. In either case, they are a threat to animals and birds.

What are nurdles?

Nurdles are lentil-sized plastic pellets used as raw material for most of today's plastic products. Made of plastics including polyethylene, polypropylene, polyvinyl chloride, and polystyrene, the pellets are transported to factories around the globe where they are melted down and used to I create plastic bags, kitchenware, bottles, and more. Through leaks, spills, and other storage or transportation errors, nurdles end up in the environment, eventually making their way to the ocean. When the X-Press Pearl container ship caught fire and sank in the Indian Ocean in May 2021. 87 containers full of lentil-sized plastic pellets aboard were accidentally spilled into the ocean.

Since the disaster, nurdles have been washing up in their billions along hundreds of miles of Sri Lanka's coastline, according to reports.

Why nurdles are a concern

According to The Guardian, 250,000 tonnes of the pellets end up in oceans each year. Because of their size and colour, nurdles look a lot like fish eggs, which makes them particularly appealing to seabirds, and other marine animals. Accidental ingestion of nurdles can cause ulcerations, starvation and eventually deaths in marine animals. Further, nurdles absorb toxins and harmful chemicals like persistent organic pollutants (POP) found in the air, and water. POP come from pesticides, toxins and other harmful chemicals. After nurdles absorb these toxic chemicals, they are eaten by fish and get passed on in the food chain. The toxin may eventually end up on our plates.

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Vicuna is a South American member of the camel family, Camelidae, that is closely related to the alpaca and llama.

It has large eyes, triangular ears, a small wedge shaped head, and a long neck and legs. Its body is covered with long, fine, soft, and lustrous coat that varies in colour from light cinnamon to pale white.

It grazes on low grasses and ruminates when resting. They live in family-based groups and use communal dung heaps to mark our territorial boundaries. . When in danger, it emits a high, clear whistle.

These animals are herbivores, which means they eat only plants. While their cousins to the south feed on both grasses and shrubbery, Vicunas only graze on grasses.

They have long teeth that grow continuously, much like those of the rodent family. These teeth allow them to crop short grasses without grinding their teeth down. This species also utilizes mineral deposits, like salt licks.

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Emu is a flightless bird endemic to Australia. It is the second largest bird after ostrich.

It has a long neck, sharp beak and small wings. Its body is covered with light-brown feathers. Each foot has three forward-facing toes that allow it to grip the ground while running. Also, it uses its legs for kicking the predators when faced with danger.

It feeds on fruits, seeds, plant shoots, small animals, animal droppings, and insects. It can survive long periods without food.

It swallows small rocks and pebbles to facilitate grinding of food and accelerate digestion. Females lay large, emerald-green eggs and males incubate the eggs for about seven weeks without drinking, feeding, defecating, or leaving the nest.

What they lack in wing size emus make up for with leg power. On top of the sheer size of their legs, a few special features help boost their strength. Emus are unique among all bird species, for example, in having a gastrocnemius. This powerful muscle, located on the back of the lower leg, forms part of what's known as the calf muscle in humans.

Emus have capitalized on the presence of people in Australia's inland, the Smithsonian Conservation Biology Institute (SCBI) explains. Farmers and ranchers set up water sources the birds can exploit, which has let emus expand into habitats that were once too dry. Fences can help fend off emus, but not all farmers want to keep emus away. Some farmers see the birds as beneficial because they eat the burrs that entangle sheep wool as well as caterpillars and grasshoppers.

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Sloths are the slowest moving animals in the world, generally travelling no more than 38 metres a day. These tree-dwellers are found in the jungles of Central and South America. Because of the humid conditions they live in, algae grows on their thick fur, providing them with camouflage.

In 2016, scientists at the University of Wisconsin-Madison announced the three-toed sloth is officially the slowest mammal on earth. Sloths spend the majority of their time eating, sleeping, and resting in jungle treetops across Central and South America. Similar to the koala, sloths do not have a nutrient-dense diet. They have a slow metabolism to cope with their low calory intake and move very slowly to preserve their energy. As they spend most of their time curled up in trees of the jungle, they are seldom met with the threat of predators thus have no need to move quickly. On average sloths travel 41 yards per day and sleep for around 15 hours.

Sloths are solitary creatures that rarely interact with one another outside of breeding season. But sloths have little time to feel lonely given their rigorous sleep schedule. Captive sloths typically sleep for 15 to 20 hours per day, while wild sloths rarely rest for more than 10 hours, according to research by the Planck Institute for Ornithology in Starnberg, Germany. Sloths prefer sleeping while curled into a ball in the fork of a tropical tree. They also like to sleep hanging by their claws from tree branches.

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Adelie penguins breed and raise their young on the continent of Antarctica. In September and October—springtime in that part of the world—thousands of Adelies gather on the rocky Antarctic shoreline.

Adelie penguins build nests by scooping out areas in the ground. The female usually lays two eggs in the nest. Adelie penguin eggs hatch in December.

In the Antarctic winter, the Adelie penguins live at sea. Both parents care for the eggs. While one stays behind keeping the eggs warm and safe from predators, the other parent heads out to sea to eat. They feast mainly on krill, tiny shrimplike animals, but also eat fish and squid.

Parents take turns caring for their youngsters after they hatch until the chicks are about three weeks old. At that point, both parents may leave to forage for food while the chicks gather in the safety of a large group of other young penguins. These groups of young Adelies are called creches.

By March, when Adelie chicks are about nine weeks old, their downy baby feathers have been replaced by waterproof adult feathers. They plunge into the sea, and start hunting for food on their own.

Like other penguin species, Adelies are excellent swimmers. They're powerful and graceful in the water, with torpedo-shaped bodies that pierce through the water. Their modified wings help propel them through water instead of air. These birds are swimmers, not fliers.

Credit : National Geographic

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It gives its beloved a stone as a present to show that he will be a good partner. This species of penguins uses only stones to build nests and not moss or grass.

Not just any rocks, though -- male gentoo penguins search through piles of pebbles to find the smoothest, most perfect ones. When a penguin has selected his pebble, he presents it to his intended companion. If she approves, she puts the stone in her nest and the two are well on their way to becoming mommy and daddy birds. Pebbles are so important to the penguins that males often fight over the prettiest selections.

Penguins shout their love for each other by screaming it out loud. They aren't shy about expressing their love for their mate. Saying "I love you" is just a normal part of their day, and they're willing to express their sentiments often.

Penguins often dance for joy at the sight of someone they love. They sing their love for each other. Penguins are certainly not shy about expressing their love. Like humans in successful relationships, they find that hanging out with their partner is the greatest joy of life.

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A keystone species is one that has an incredibly important role to play in an ecosystem. Without this species, ecosystem would be dramatically different or may even stop existing altogether. It can be any organism, from large animals to microscopic bacteria. In short, a keystone species is what holds a habitat together.

There's a call to protect the tiger because as a keystone species, this top predator plays a significant role in the health and diversity of an ecosystem.

If it disappears, the population of its prey - usually ungulates - will go up, and this will result in the decimation of vegetation, leading to a collapse of the ecosystem.

Not just animals, birds and insects, even plants can be keystone species.

Mangroves are a keystone species that firm up shorelines and reduce erosion. They provide a safe haven and feeding area for small fish among their roots, which reach down through the shallow water.

It is true that if bees go extinct, so would humans. This keystone species plays a very important role in keeping the world going.

As the most important pollinators, they are responsible for about a third of the world's total food production. Without bees, there would be food shortage, and eventual human collapse.

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Squids and octopuses are cephalopods, members that fall under the molluscan class Cephalopoda. But these aquatic invertebrates do not have shells. Their blood is blue due to the presence of copper in it, and they also have three hearts each. But octopuses and squids differ in their physical characteristics, habitat, and behaviour.

An octopus has a round head, while a squid's head is triangular in shape. Octopuses do not have any bone in their body, while squids possess a stiff structure known as a pen that acts as a flexible backbone. Octopuses do not have fins, while squids have two on their heads. Both have eight arms, but squids have two specialized tentacles in addition which are used to catch prey.

While octopuses live in the ocean floor, squids live in the open sea at various depths depending on the species. Octopuses feed on crustaceans on the sea bottom, while squids feed on shrimps and fishes. Usually, squids are larger than octopuses.

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When it rains, we get to see several types of creatures we may not see otherwise. In the last few weeks, especially in Tamil Nadu and Kerala, one creature has made headlines for showing up in large numbers due to the rains. But it's not really good news. Why? Come let's find out.

It is possible that you've seen the giant African snail. Especially around the time it rains. With its large, striped shell firmly on its back, you may have spotted it crossing a wet road, climbing a gate, or munching on some plant. As the name suggests, it is native to Africa, and can grow to be a large snail. And it is one of the most invasive species in the world, and is said to have landed in India several decades ago inadvertently. That they have no natural predators has played a big role in their numbers increasing. Today they are found in several States, including Tamil Nadu, Kerala, Karnataka, Andhra Pradesh, and the North-East regions too. They eat native plants and crops, altering the ecosystem and denting farmers' income. It is said that they consume even paint! They are not just pests , they are also a health hazard to humans. They can cause severe diseases as they host parasites. For this reason, they cannot be consumed by humans.

Did you know?

• Just a few months ago, a village in Kerala's Alappuzha district came up with a novel plan to get rid of this invasive species, which causes extensive damage to crops. Onam bumper tickets with a chance to win Rs. 12 crore were on offer for 10 people catching the highest number of snails.
• Recently, after witnessing the continuing menace of these snails, a group of walkers in Kerala made an announcement to buy these snails each for a rupee from residents. Apparently, within just a few days, they bought over 3,500 snails!

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Is the destruction of wetlands driving out these magnificently colorful insects?

Dragonflies are very sensitive to changed in the environment .loss of the marshes swamps and free flowing rivers they breed in are some of the risk factors.

What a new report says...

The destruction of wetlands is driving a decline of dragonflies around the world with one sixth of species of the magnificently colorful insects threatened with extinction conservationists said on Thursday.

A report from the International Union for Conservation of Nature presented the first assessment of all 6,016 dragonfly and damselfly species globally, and found that at least 16 per cent of them risked going extinct.

What's driving the extinction?

The decline is a symptom of widespread loss of the marshes, swamps and free flowing rivers they breed in driven mainly by the expansion of unsustainable agriculture and urbanization around the globe, IUCN said in the update of its "Red List of threatened species.

"By revealing the global loss of dragonflies, today's Red List update underscores the urgent need to protect the world's wetlands and the rich tapestry of life they harbor. IUCN director general Bruno Oberle said in a statement

Why are wetlands disappearing?

Globally, these ecosystems are disappearing three times faster than forests. A report published three years ago by the Ramsar Convention on Wetlands found that 35 per cent of the world's wetlands were lost between 1970 and 2015, Wetlands store carbon, protect against floods and offer habitats for one in 10 of the world's known species.

What are the warning signs?

The welfare of dragonfly species is an especially good indicator for how the wetlands are doing.

"They're very, very sensitive to changes in the environment. And so that is an early warning signal to what's happening to wetland systems around the world." Craig Hilton-Taylor, who heads IUCN's Red List unit said.

He said a lack of data meant the true number teetering on the brink of extinction could be as high as 40 per cent.

Where the problems loom large...

The situation is particularly dire in South and Southeast Asia, where more than a quarter of all dragonfly species are threatened, IUCN said.

This is largely due to the clearing of wetland and rainforest areas to make room for crops like palm oil, it explained. Pesticides, other pollutants and climate change are also growing threats. AFP

The red list

• With the latest update, the Real List now includes assessments of 142,577 species of animals and plants, including 40.084 considered to be threatened with extinction.
• This marks the first time that the number facing the highest risk has passed 40.000

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'Moo've over, I want my friend

Cows are often considered fat and idle, and maybe there are a few who think they're cute. But, how many of you have looked at a herd of cows and wondered which of them are good friends? Seriously, cows are more emotionally complex than we give them credit for. A research conducted in Northampton University found that not only did they prefer the company of cows from their herd, they were happiest in the company of a best friend! The next time you see one on the road, maybe you could ask her to go look for her friend instead of saying, 'Shoo!'

Giggling and tickles – rats like it too!

Who knew rats enjoyed being tickled as much as we do? A team led by Dr Jaak Panksepp spent two weeks tickling rats and discovered that not only did they enjoy being tickled, but they also giggled in a way only rats can! The sound made by the rats while giggling was similar to the sound they made when they played together, which shows that they are indeed having a good time. Another interesting find was that the rats that didn't enjoy being tickled tended to be anti-social and neurotic.

Ha, ha... how funny!

Marmosets may be good at small talk, but chimps take the prize for fake laughter. No, it's not just us humans who fake a laugh even when we don't get the joke. A research team from University of Portsmouth found that actively engaged chimps responded with real laughter while those chimps nearby that weren't taking part in the fun, showed a more deliberate, less intense laughter.

Aesop's fable proved true

Amazingly, crows have been found to have an intelligence equivalent to a 7-year-old kid. A research conducted in New Zealand proved the famous Aesop's fable true. Yes, crows drop pebbles and solid objects in a tube of water to reach the food in it. That's not all, though. New Caledonian crows are supposed to be very intelligent they can craft tools like hooks and prodding sticks to pull out grub from logs and branches.

Let's have a chat

Do you chat with the auto driver when the silence seems too uncomfortable? Or make small talk with a classmate whom you hardly know? Well, it's not just humans who indulge in small talk... Marmosets, a type of monkey native to South America, also chatter idly. In fact, research found that these monkeys are so polite too... they wait for a few seconds after a monkey chats before putting in their thoughts. A chat session sometimes lasts even for 30 minutes, apparently.

More for less

Are dolphins master bargainers? Dolphins are known for their intelligence, as studies have shown. Particularly interesting is the case of a dolphin called Kelly at the

Institute for Marine Mammal Studies in Mississippi. A group of dolphins were trained to pick up pieces of litter in the pool and exchange them for food. Kelly took this one step forward - she hid the paper under a rock, tore pieces of it and handed it over in exchange for food. Kelly clearly knew that tearing the paper up meant more food. Now how cool is that?

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The tiny Pistol Shrimp has no vocal cords but is the world's loudest animal, snapping its claws at 200 decibels.

The shrimp closes its claw so fast that it generates a bubble that is louder than a bullet when it implodes, according to Stanford University. The "snap" stuns its prey, giving it enough time to attack and feed on its prey.

It's one of the more common sounds in the ocean, but it may become louder and more frequent as water temperatures in the ocean rise, said Aran Mooney, a marine biologist from Woods Hole Oceanographic Institution.

Mooney, along with researcher Ashlee Lillis, listened to shrimp sounds at different temperatures and found that the snapping shrimp emit louder, more frequent sounds as water temperatures rise. He will present the findings at the Ocean Sciences Meeting in San Diego Friday.

Shrimp tend to move much faster when water is warmer because they are cold-blooded. Per CalTech, most cold-blooded creatures' muscle activity is expedited when their surroundings are hot.

Credit : USA Today 

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The Leaproach (Saltoblattella montistabularis) has a talent that none of the other 4000 plus known species of cockroaches have. It's one of the insect world's best jumpers. Discovered in Cape Town, South Africa, it is a third of an inch long, and can jump 50 body lengths (we can only manage about 2) at take-off velocities of 6.9 feet per second while experiencing an acceleration of 23 g (humans would pass out at only 5 g).

About a third of an inch long, the roach is technically named Saltoblattella montistabularis, but let's stick with Leaproach. (The researchers came up with that nickname.) Its jumping movements were captured with a high speed camera operating at 2,000 frames per second.

Analysis of the photos showed that Leaproach propels itself jumping by rapid movements of enlarged hind legs. The muscles of these buff legs contract long before take-off, storing energy that is suddenly released a/la a catapult.

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A chameleon's tongue moves at ballistic speeds - the acceleration reaches 50G - five times faster than an F16 fighter jet! The burst of speed is produced by spiral muscles in the tongue, which contract width-wise to make them stretch forward. A lubricant allows the muscles to slide at time-slicing speeds.

These awesome ballistic tongues are the result of a remarkable coordinated system of body parts that builds up and quickly releases energy. Here’s how it works.

At the core of a chameleon tongue is a slim, tubular bone wrapped in thin layers of elastic tissue. Enveloping all of this is a layer of muscle.

The elastic tissue is made of collagen, a common biological material that gets remarkable stretchiness from its springlike fibers. Half the fibers spiral clockwise and half anticlockwise. Together they form a diagonally crosshatched pattern that looks like the stretchy plastic mesh sleeves used to protect glass bottles.

When chameleons sight prey, they get ready, aim, and “load” their tongues by contracting their tongue muscles. The muscles squeeze inward around the collagen fibers, compressing them into tight coils. The fibers are now packed with stored energy, like a jack-in-the-box ready to pop.

The muscles and compressed collagen layers slide forward along the well-lubricated bone. At its tip, the bone thickness tapers down sharply, expanding the space for the collagen fibers. Suddenly uncompressed, the fibers spring forward, powered by their own momentum. Stored potential energy reverts to kinetic energy, amplifying the tongue’s speed and power. It shoots out at accelerations of 2,590 meters per second squared, or 264 G (faster than a fighter jet), and smashes its sticky tip into its prey within two-hundredths of a second.

Credit : Ask Nature 

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Snails can crawl along the edge of a razor blade without cutting themselves! Snails produce a colourless, slimy mucus, which in addition to helping them move and stick to surfaces, forms a protective layer under them to protect them as they move along.

Snails produce slime, which is a kind of mucus, via a special gland on the front of the snail's foot. Scientists initially thought that the purpose of the slime was to enable snails to move. Over the years, however, researchers have learned that snail slime is a special substance with unique properties and several purposes.

Snail slime has the consistency of a liquid gel. At rest, it's solid and sticky. Under pressure, though, it liquefies and acts as a lubricant.

Although their slime definitely helps them to move along more efficiently, snails don't need it to move. They have muscles on the underside of their feet that generate pulses that propel them forward.

As they travel on the slime they produce, the slime helps them to stick to whatever surface they're on while their muscles are at rest. As their muscles contract and push down to propel them forward, however, the slime becomes more liquid and makes movement easier.

Credit : Wonderopolis 

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