My Science School

Songbirds rehearse their melodies by 'singing in their sleep'. Scientists believe that the birds dream of singing to help them hone a range of different tunes. Young birds learn to sing by listening to adults and then practise by listening to their own attempts. Research suggests that songbirds store a song after hearing it, then rehearse it later in their sleep.

The researchers compared the activity of each neuron while the awake bird sang, while a sleeping bird could hear a recording of its own song, and during undisturbed sleep.

While the birds are awake and singing the neurons fire in a pattern that is unique to the note and syllable components of each bird's individual song. When the awake bird hears its own song, these neurons do not fire in response.

But in the sleeping bird listening to a recording of its own song, the neurons do fire in the pattern identical to song production, though the bird produces no sound. This pattern of firing during listening, like the pattern of firing necessary to produce song, actually anticipates the next song "syllable," or set of notes.

"The learned song is a temporal code that uses the nerve impulse spikes of single cells in precisely matched patterns for hearing and singing. The two patterns can be 'mapped' to each other with spike-by-spike precision," said Margoliash. "The bird is using the preceding sound to predict how to generate the next syllable."

Understanding how patterns of behavior are represented in the brain has been a major problem for neurobiologists.

"Previously we found that during singing song is represented as a temporal code. Now, much to our surprise, we find this correspondence in single cells of matched sensory and motor patterns. Forming this mapping of sound and action is the process of learning," said Margoliash.

During undisturbed sleep, the researchers discovered, the neurons spontaneously fired the same complex song production patterns in bursts. Interestingly, these activity patterns were at slight variance, as if the bird was rehearsing a variety of slightly different songs, sometimes with slower or faster tempos.

How does the bird learn to correct its song when by the time it hears it the neuron is now engaged in the production of the next sound? Practice during sleep may be part of the answer.

"In contrast to the prevailing idea that it learns by making moment-to-moment adjustments, we think the bird stores the song production pattern and reads it out at night, an 'offline' solution to the timing problem," said Margoliash. "The zebra finch can replay and strengthen the pattern during sleep."

The next step, according to Margoliash, is to explore what happens to song learning when the sleep replay is interrupted.

"If we can describe the rules by which sleep acts on song learning, these lessons may apply to learning in other animals, including humans," said Margoliash. "Neurobiologists have often found that lessons learned from weird and wonderful animals apply to all animals. The beautiful songs of birds could have much to teach us about how we learn."

Credit : Science Daily 

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Saltwater crocodiles enjoy "catching a wave" and can travel hundreds of kilometres by surfing on ocean currents. This current riding behaviour allows for the conservation of energy. Estuarine or saltwater crocodiles (Crocodylus porosus), found in Southern Asia and Australia, are the world's largest reptiles and can grow up to 5.5 metres in length.

Working at the remote Kennedy River in northeastern Australia, the team of scientists — which included the late Steve Irwin, "The Crocodile Hunter" — tagged 27 adult seawater crocodiles with sonar transmitters, employing 20 underwater receivers deployed along a 39-mile-long stretch of the river (63 km) to track the reptiles' every move for more than 12 months. They found both male and female adult crocodiles undertook long-distance journeys, regularly traveling more than 30 miles (48 km) from their home area to the river mouth and beyond into open sea.

The scientists also discovered the "salties" always began long-distance travel within an hour of the tide changing, allowing them to go with the flow. They halted their journeys by hauling out onto the river bank or diving to the river bottom when the currents turned against them.

The researchers originally were just aiming to investigate the territorial habits of the crocodiles and how they divvied up land among themselves.

Credit : Live Science 

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Before the 1600s, a giraffe was known as a Camelopard, deriving from the ancient Greek for camel and leopard, referring to its camel-like shape and leopard-like colouring. The word 'giraffe' has its earliest-known origins in the Arabic word zarafah meaning "fast-walker. The modern English form developed around 1600 from the French word girafe.

In 46 BC, Julius Caesar had celebrated his triumphs in Egypt by returning to Rome with a vast menagerie, the star attraction of which was a giraffe, the first ever seen in Europe. The Romans did not know what to make of such an animal and named it the "cameleopard", for it seemed to them to embody characteristics of both the camel and leopard. Caesar had the animal torn to shreds by lions in the arena, probably to emphasize his power by the disposal of such a rare creature in a casual manner. Lorenzo had read of the success of the spectacle of Caesar's giraffe and saw a way to cement his reputation in Florence by emulating it. He also realised that he could gain further political influence by passing the animal on and promised to send it to Anne of France, after its sojourn in Florence.

Whether the giraffe was provided by Qaitbay is uncertain as there is no record of its procurement, but it seems likely: he is known to have had giraffes in his menagerie; he appealed for Lorenzo for help against the Ottomans around the time of the giraffe's arrival in Florence and Lorenzo did intercede on his behalf shortly afterwards.

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The Octopus Stinkhorn Mushroom looks like an octopus and stinks like rotting flesh to attract flies that spread its spores, ensuring that its species spreads. The six-tentacle fungus, Clathrus archeri, is native to New Zealand and Australia, but is also found in the U.K. and North America.

As with all fungi, the part we see is just the reproductive organ or fruiting body. The majority of the fungus is a network of filaments underground and running through dead wood. These filaments feed on dead plants and animals, helping break them down to form soil.

When they are ready to reproduce, stinkorns grow one or more pale, egg-like structures above ground – visible at the base of the stalk in the photo above. Four to eight red arms, each up to 10 centimetres long, then grow out of the egg on a short white stalk. The arms are covered in a foul-smelling brownish slime. The slime contains spores; it smells like dung or rotting flesh to trick flies and other insects into landing on the spores. These insects then transport the spores to the next place they land, allowing the fungus to spread. Despite the disgusting smell, octopus stinkhorn is not known to be poisonous to humans or pets.

Credit : Ascension 

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Eucalyptus deglupta or the "rainbow eucalyptus" is the most colourful tree in the world. The previous season's bark peels off in strips to reveal a brightly coloured new bark below, with vertical streaks of red, orange, green, purple, blue and grey. Its original homes are the Philippines (particularly Mindanao Island), Indonesia and New Guinea. Now, it thrives in nearly every tropical and subtropical region of the world; Central America, the Caribbean, and South Pacific islands. It is the only eucalyptus species indigenous to the northern hemisphere. It grows quickly, reaching a trunk diameter of 6 feet and soaring to over 200 feet!

What makes these trees intriguing is their colorful bark that looks like a color pencil that’s been sharpened. It starts off as a typical tree with a brown bark until the bark starts to shed in summer, and then the magic of nature happens. As it slowly sheds, it reveals a bright green inner bark that changes color as it ages. At some point, it turns purple, and then after some time it turns orange, and after it has been exposed to the air some more it turns a shade of maroon or blue.

The colorful streaks happen because parts of the bark don’t shed all at once, the entire bark doesn’t peel at the same time. Instead, it peels part by part, little by little,  so others that have just recently started peeling would appear green, the rest could be orange or any other color of the rainbow (hence its name) depending on how long it has been exposed to the environment. Once this process of shedding is complete, it goes back to its original brown color until the next cycle. However, people have observed rainbow trees that grow in tropical climates have a brighter and much more colorful bark than those that grow elsewhere.

They are mainly cultivated for its wood used as construction lumber, particle boards, and plywood for making cabinets. As it is also a good source of pulp, some use the tree to produce paper although the product is pure white and not rainbow-colored. In recent years people have also been using these colorful trees as an ornament used mainly for landscape design to add color to an otherwise purely green scenery in the park, and home or botanical gardens.

Credit : World Atlas 

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Some species of ants, e.g., army ants, are completely blind and can become disorientated and march in circles until they die of exhaustion. Army ants navigate by following pheromone trails left behind by others. However, should an ant lose the scent, it might loop around and start following another ant in the group; the others follow and a huge ant spiral forms. The largest ant 'death spiral' ever discovered was 1200 feet in diameter, with each ant completing a circuit in two and a half hours.

The insects, found in South America, hunt in swarms of up to 200,000 individuals and are capable of killing 100,000 living creatures a day.

They eat essentially anything that moves and there’s very little defence, because they attack in such huge numbers.

Cornell University entomologist Sean Brady, while studying army ants in South America, described the amazing phenomenon of the insects marching, which is entirely silent.

He explained that you know they're coming from the reactions of other creatures in the jungle.

He said: 'The other insects are scared, and they make noises as they flee the invading army. Ant birds follow the ants from the sky and feast on the remnants left behind by the ants.

'You will hear the high-pitched chirping of the other insects, and you'll hear them and other small animals scurrying in fear. They know what is next.'

Credit : Daily Mail 

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Baby turtles make sounds to communicate with each other while still in the egg, to help synchronize when they hatch. Being able to coordinate hatching times is an important survival technique. If they all hatch together, there is a better chance that more of them will make it across the beach and into the water.

Researchers from Brazil, Mexico and the US got together to study the nests of 12 leatherback sea turtle nests in Oaxaca, Mexico. Starting on day 51, the point at which the babies's ears should be developed enough to hear sounds, they monitored the nests for any signs of noise. They immediately began detecting sounds, recording more than 300 different noises in total. They classified the sounds into four categories, including chirps, grunts and "complex hybrid tones," or sounds composed of two parts that they classified as pulse characteristics and harmonic frequency bands. 

That latter sound - the most complex of the bunch - was only recorded in nests that contained just eggs, rather than eggs and hatchlings (most had begun hatching by day 55). The baby turtles, the researchers believe, may be coordinating their hatching timing by emitting the sounds. This phenomenon has been observed in other animals ranging from birds to crocodiles, likely as a survival mechanism. In the case of the turtles, hatching en masse brings a certain strength in numbers. While some babies will be picked off by predators, a bird can only eat so many sea turtles at a time, meaning at least a few will make it to the sea. 

This finding, the authors point out, means that light pollution might not be the only anthropogenic nuisance threatening baby sea turtle survival. Noise pollution could be affecting them, too. 

Credit : Smithsonian 

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There are more statues of the king of the jungle across the world than actual wild lions. In the last 50 years the lion population has declined nearly 95%. These amazing creatures are victims of habitat loss and degradation as well as human conflict.

The temporary statue is built entirely from clockwork mechanics, representing how time is running out for many big cats. It joins the four famous bronze lions which have been based in Trafalgar Square since 1867.

Tigers are undergoing a similarly drastic decline with a wild population which was 10,000 strong in 1900 now down to just 3,500, whilst Cheetah numbers have fallen from 100,000 in 1900 down to less than 10,000.

Co-founder of the Big Cats Initiative Dereck Joubert said: “We no longer have the luxury of time when it comes to big cats.

Credit : Mirror

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Extraordinary fungus farmers

You've probably seen pamphlets on how to grow mushrooms at home and make money. Not surprisingly, many of us wonder if it would even work out. But leafcutter ants have no such qualms - they've been master fungus farmers for centuries. If you've seen a leafcutter ant carrying a piece of leaf you assume that it's going to be food. But these leaves are taken to a garden space and used as fertilizers on a fungal farm tenderly cared for by the ants. Some ants even lick the growing fungi to spread a type of bacteria that kill other competing fungi, thus acting as a pesticide. If this isn't advanced farming, what is?

Tireless invaders

Pine processionary caterpillars bear an uncanny similarity to Genghis Khan and his army. While Genghis Khan invaded cities, these caterpillars target pine forests. Hardly 2 cms in length when they emerge out of their cocoons, these caterpillars are blessed with super strong mandibles capable of chewing pine needles soon after birth. But that's just the beginning - - as they grow, they form a single line army and invade pine trees. They march bravely even at sub-zero temperatures and destroy massive coniferous forests in a very short time!

Choosing summer retreats

Do you dream of warm, sandy beaches in the winter and snowy slopes during the sultry summers? Guess what? Locusts love such getaways, too. You may travel solo or with a small group of friends or family, but locusts do it differently. When they migrate together, what a sight it is! Referred to appropriately as the 'gregarious phase', millions of locusts fly together in a mighty swarm that intimidates creatures big and small. They can ravage crops and forests leaving behind a sorry mess. They travel for very long distances, sometimes from northwest Africa all the way to Britain or even to the Caribbean if they fancy a vacation!

A taste for electronics

What was once the home of fire ants is now owned by tawny crazy ants that invade houses with a kind of determination that is plain scary! There was a time when people hated fire ants but they are nothing when compared these ants. Fire ants built mounds in backyards and hardly bothered you unless you stepped on their home. These crazy ants have been driving people mad. This is particularly because of the interest they show in electronic equipment. They have been spotted forming bridges between electrical contact points and causing short circuits!

Simple brain, amazing focus

Dragonflies possess one amazing quality that many of us struggle with. Did you know that dragonflies can focus on a target and filter out other useless information? This process is known as 'selective attention'. Imagine how useful it would be if we could do that. If only dragonflies could write a book on focus and concentration... now that would be a bestseller!

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Seven complete specimens of 100-million-year-old flowers have been discovered in Myanmar. The flowers are only 3.4-5.0 mm small and were likely dislodged from a tree by a Triceratops or Tyrannosaurus rex passing through the jungle. The flowers fell into resin deposits on the bark of an araucaria tree; the resin then fossilized into amber. Named Tropidogyne pentaptera for the Greek words for five (penta) and wing (pteron), the flowers are part of the Cunoniaceae family found in Australia and Papua New Guinea. Researchers believe that the flowers were likely encased in amber some time before the supercontinent of Gondwanaland broke up, which would explain how a species found in Myanmar could be related to modern-day flowers in Australia.

This study builds on earlier research also involving Burmese amber in which Poinar and Chambers described another species in the same angiosperm genus, Tropidogyne pikei; that species was named for its flower's discoverer, Ted Pike. Findings were recently published in Paleodiversity.

"The new species has spreading, veiny sepals, a nectar disc, and a ribbed inferior ovary like T. pikei," Poinar said. "But it's different in that it's bicarpellate, with two elongated and slender styles, and the ribs of its inferior ovary don't have darkly pigmented terminal glands like T. pikei."

Both species have been placed in the extant family Cunoniaceae, a widespread Southern Hemisphere family of 27 genera.

Poinar said T. pentaptera was probably a rainforest tree.

"In their general shape and venation pattern, the fossil flowers closely resemble those of the genus Ceratopetalum that occur in Australia and Papua-New Guinea," he said. "One extant species is C. gummiferum, which is known as the New South Wales Christmas bush because its five sepals turn bright reddish pink close to Christmas."

Another extant species in Australia is the coach wood tree, C. apetalum, which like the new species has no petals, only sepals. The towering coach wood tree grows to heights of greater than 120 feet, can live for centuries and produces lumber for flooring, furniture and cabinetwork.

So what explains the relationship between a mid-Cretaceous Tropidogyne from Myanmar, formerly known as Burma, and an extant Ceratopetalum from Australia, more than 4,000 miles and an ocean away to the southeast?

That's easy, Poinar said, if you consider the geological history of the regions.

"Probably the amber site in Myanmar was part of Greater India that separated from the southern hemisphere, the supercontinent Gondwanaland, and drifted to southern Asia," he said. "Malaysia, including Burma, was formed during the Paleozoic and Mesozoic eras by subduction of terranes that successfully separated and then moved northward by continental drift."

Credit : Science Daily 

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It would take 1.2 million mosquitoes, each sucking once, to completely drain the adult human body of blood! In the Arctic, Canadian researchers who bared their arms, legs, and torsos reported as many as 9,000 bites per minute from swarming, newly hatched mosquitoes. At that rate, an individual could lose half his blood in two hours!

A condition called hypovolemic shock sets in after you lose about 20% of your blood, and it leads to major organ failures because your heart loses the pressure necessary to circulate blood.

Another thing to consider is the amount of skin a human has for the mosquitoes to bite. An average person has about 1.75 square meters of skin. That means you'd need almost 6,300 Asian tiger mosquitoes feeding on each square centimeter of skin on your body

So unless they set up an orderly queuing system to get at your skin, there's little to no risk of having your blood drained by mosquitoes, let alone encountering a swarm of millions. But mosquitoes are not necessarily the most profilic bloodsuckers.

Credit :  Insider 

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The World Cancer Research Fund (WCRF) has provided a list of recommendations that may help prevent up to 40 per cent of all cancer cases. Here are some of the top tips you can follow:

• Watch your weight and exercise regularly. Ensure you include at least 75 minutes of vigorous exercise every week.
• Follow a healthy diet and eat at least five portions of fruit and vegetables a day, particularly green leafy vegetables like spinach and broccoli.
• Avoid processed foods high in fat, starches or sugars, such as readymade dishes, snacks, cakes, biscuits and sweets.
• Don't take unnecessary dietary supplements; if you eat a healthy diet, you don't need supplements.
• Instead of drinking fizzy drinks and sweetened fruit juices, try to drink more water and unsweetened drinks. Cut down on alcohol.

Credit : Hindustan Times

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Shark teeth have naturally built-in toothpaste! The surface of shark teeth contains 100 per cent fluoride, the active ingredient in most toothpastes. They also have the handy ability to replace their teeth several times during their lives, because their teeth sometimes end up stuck in prey or are otherwise forced out.

According to the study, their teeth are perfectly designed for such tasks, never suffering from cavities.

While shark teeth contain the mineral fluoroapatite (fluorinated calcium phosphate), the teeth of humans and other mammals contain hydroxyapatite, which is an inorganic constituent also found in bone, explained co-author Matthias Epple.

“In order to make teeth more acid resistant, toothpaste often contains fluoride,” Discovery News quoted Epple, a professor of inorganic chemistry at the University of Duisburg-Essen, as saying.

“In the surface of human teeth after brushing, a small amount -- much less than 1 percent -- of hydroxide is exchanged by fluoride.

“In contrast, (the surface of) shark teeth contains 100 percent fluoride. In principle, sharks should not suffer from caries. As they live in water and as they change their teeth regularly, dental protection should not be a problem for sharks,” he said.

Credit : Hindustan Times 

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A species of "immortal" jellyfish can age backward. The Turritopsis dohrnii jelly fish can revert back to its juvenile stage from its adult stage, doing it several times over, making it the only known officially immortal creature. When starvation, physical damage or other crises arise, instead of sure death, Turritopsis turns itself into a bloblike cyst, which then develops into a polyp colony (the first stage in jellyfish life) which can spawn hundreds of genetically identical jellyfish - near perfect copies of the original adult.

Fully grown, Turritopsis dohrnii is only about 4.5 mm (0.18 inches) across, smaller than a pinky nail. A bright-red stomach is visible in the middle of its transparent bell, and the edges are lined with up to 90 white tentacles. These tiny, transparent creatures have an extraordinary survival skill, though. In response to physical damage or even starvation, they take a leap back in their development process, transforming back into a polyp. In a process that looks remarkably like immortality, the born-again polyp colony eventually buds and releases medusae that are genetically identical to the injured adult. In fact, since this phenomenon was first observed in the 1990s, the species has come to be called “the immortal jellyfish.”

The cellular mechanism behind it—a rare process known as transdifferentiation—is of particular interest to scientists for its potential applications in medicine. By undergoing transdifferentiation, an adult cell, one that is specialized for a particular tissue, can become an entirely different type of specialized cell. It’s an efficient way of cell recycling and an important area of study in stem cell research that could help scientists replace cells that have been damaged by disease.

As for Turritopsis dohrnii, this jelly is not only an extraordinary survivor. It’s also an increasingly aggressive invader. Marine species have long been known to hitch rides around the world in the ballasts of ships. Researchers have recently identified the immortal jellyfish as an “excellent hitchhiker,” particularly well-suited to surviving long trips on cargo ships.

Credit : AMNH

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Brinjal or aubergine is a berry by botanical definition, although it is prepared as a vegetable. Related to the tomato and potato, aubergine has the highest concentration of nicotine of any edible plant.

Brinjal is a rather small plant that grows up to 1.5 m. Brinjal is classified as a herb because of its non-woody stem. Its simple leaves are oblong to oval, slightly lobed, with its underside a paler green than the upper surface. Both leaves and stem are covered with fine hairs. Its flowers sprout singly or in small clusters from the leaf axils. Individual flowers are star-shaped, light purple in colour and have short stalks. There are five stamens attached to the corolla tube and a single superior ovary.

Its fruits are berries with many seeds and are either long or round and vary in colour according to the variety: white, orange, green, purple or black. It is a perennial and fruits all year round.

Brinjal fruits are commonly considered as vegetables. They are cooked in various ways such as baking, barbecuing, frying or pickling. They can also be pureed, flavoured, and used as a dip or chutney as in Mediterranean and Indian cuisines. In Indian cuisine, they are used in curries and even made into soufflés. The cut fruits are typically soaked in cold salted water before cooking to avoid discoloration and to remove its mild bitterness.

Credit : eresources

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