Obe Danumata (ඔබේ දැනුමට)

T he deciduous trees are the ones that lose their leaves in autumn. These trees are largely the broad-leaved trees of the northern hemisphere. Winter in this region is very harsh, so the trees shed their leaves in autumn to spend the winter in a state of dormancy . They do so to conserve water, by avoiding transpiration through leaves. There is frost all around and the roots get no water from the soil. Maples , magnolias, oaks, beech are some deciduous trees.

T he baobab tree is a native of tropical Africa. It is a very strange looking tree which has a barrel like trunk that can reach 30 feet or more in diameter and its height is not proportionately great. The fruit of this tree is large, gourd like and woody which contains a pleasant and cool tasting juice . A strong fibre from the bark is used to make ropes and cloth. The wood is soft and light and is used to construct houses.

D inosaurs appeared on Earth about 225 million years ago. But there are no living dinosaurs today. They seem to have become extinct at the end of the Cretaceous Period, about 65 million years ago. It is quite possible that the plants they ate died out. Or maybe a comet or meteorite hit the Earth , causing an explosion that threw clouds of dust into the atmosphere. The dust blotted out the Sun, plants died and so did the dinosaurs.

T he howler monkeys are found in the rainforests  of South America. The deep howls of these monkeys echo around the forest at dawn and dusk. A bony box in the thick neck of these monkeys amplifies its howling calls. They make the noise to warn other howler monkeys to keep out of the family group's patch of forest, so that they can keep the food supplies there for themselves.

C uckoos are a family of parasitic birds. They do not build nests and lay their eggs in the nest of other birds. The female cuckoo keeps a watch on the nest of other birds while they build it and lay eggs. When the host parents are away, she flies down to the nest and pulls away one of the eggs with her beak. She then quickly lays her egg in its place and flies away. The poor host parents do not notice any change in the nest. After about two weeks, when the eggs hatch, the cuckoo chick pushes out of the nest. The foster parents keep on feeding the cuckoo chick which grows much larger than the foster parents. It stays with them until it is ready to fly .

T he sharks that are known to attack human beings are the tiger shark, blue and the grey nurse sharks. The most feared and aggressive of all sharks is the great white shark . The sharks may attack humans if they get attracted by underwater noises, erratic swimming , the presence of a large number of bathers or the glint of jewellery or some other article . But the sharks get highly provoked by the presence of blood. They largely attack during day time and usually about 200 to 300 feet from the shore where the water is comparatively shallow.

A lizard can shed its tail at it's will. It uses this feature as a means of self defence . When attacked by a predator, the lizard leaves behind its tail and escapes . The predator gets distracted and confused while the lizard saves it's life. The loss of the tail is temporary and the lizard gets a new tail regrown out of the tail stump.

A bout 500 species of frogs spend their lives on tree tops. Some South American tree frogs are very brightly coloured to warn predators that they are extremely poisonous to eat. All the amphibians have mucous glands in their skin to keep themselves moist. In some frogs, these glands also produce a poison so deadly that it can paralyze a bird or monkey instantly. South American Indians use secretions from golden arrow-poison frogs to poison the tips of their hunting arrows.

T he largest land mammal of all time was the giant hornless rhinoceros Indricotherium , which lived in the Oligocene epoch. It stood 5.5 metres high at the shoulder and its head would bypass a modern giraffe. Brontotheres stood at 2.5 metres at the shoulder. The horse like animal Moropus was a little smaller. All these animals browsed in the open plains.

F latworms are flat, simple-bodied worm like animals ranging from the size Of a few millimetres to larger tropical forms. These worms are largely found in temperate and tropical regions of the world. They live under the stones and leaves , in freshwater streams and ponds. A few of them also live on land. Flatworms can regenerate themselves and if a worm is cut into few pieces , each piece will grow into a new flatworm. Some flatworms are parasites. For example the flukes and tapeworms.

B ats are the only mammals which can truly fly in the dark. They are nocturnal and so are active and fly at night. The wing of a bat is different from the wing of a bird. It is a skin-like membrane, the patagium , stretched between enormously long arm and hand finger bones. Most bats are insectivorous while some are fruits-eating. The vampire bats feed on the blood of large mammals and some others feed on mice, voles, frogs and fish. Bats are able to find their prey and avoid obstacles in the dark by using a sound radar system called echolocation. They emit very high-pitched pulses of sound called ultrasound which cannot be heard by us. The sound waves bounce back to the bat after hitting an object . The bat hears the patterns of these echoes and analyses it to give a 'sound picture‘ of the object and the surroundings.

F or animals in the desert, it is a constant struggle against dry conditions to live and have a plentiful supply of liquid nourishment. They have evolved ways Fennec, a desert animal, has large ears which is used as a radiator to get rid of excess heat. Many animals are nocturnal and crepuscular, i.e. active at dawn and dusk , to avoid the heat of the sun. Many desert animals do not sweat, produce concentrated urine and dry faeces to conserve water. Herbivores like Addax and Oryx can go without water for days . They manage to have their share of water from dew and space plant-life. Sandgrouse nests in the desert. It flies long distance in search of water and carries it back for the nestlings by soaking its breast feathers. Some animals have evolved unique ways to move in the sandy deserts. Many desert rodents jump rather than walk, while some snakes like Sahara's horned wiper side winds on the sand , and the sandfish skink appears like almost swimming on sand .

M arsupials like kangaroo and koala are pouched mammals. They give birth to babies which are at a very early stage of development , very small and helpless. The babies crawl to the pouch and continue to develop there safely, feeding on mother's milk. Most of the mammals nourish their developing young ones by means of placenta in the mother's womb. Marsupials do not have placenta and they have undeveloped babies. The baby kangaroo at the time of birth, is just grape sized with tiny, hardly developed legs. It crawls on its own, up to mother's fur and then into her pouch. It hatches on to one of the mother's nipples to suck milk. It stays there for six months and keeps visiting the pouch until it is an year old.

A hermit crab, unlike other crabs, does not have a protective shell to cover its soft body. To protect itself from being preyed upon, a hermit crab uses empty snail shells. Often a fight breaks out between the crabs to occupy an attractive snail home. Sometimes the crabs eat up the snail to take possession of its shell . One species of hermit crab enters into partnership with sea anemones. The crab stays in the shell, while the anemone lives on the top of the shell. The crab provides the sea-anemone with transport and, in return, gets an extra shield against the enemy.

T he python is the longest snake in the world. Found in the tropical regions of the world, it is the reticulated python that can grow up to 30 feet in length. Python kills its prey by coiling around the prey so that it cannot breathe. Then the prey is swallowed whole . It can even kill an ox, but prefers smaller It is not animals that it can swallow whole .  poisonous and hardly attacks man. Pythons live on trees, but they also like lying in water to cool themselves. They lay oval eggs with leathery shells and guard them by coiling themselves around the eggs .

A nimals with an unpleasant taste or which are poisonous, often advertise themselves with their bright colouring. The bright colours warn the predators to avoid these animals and keep them at a bay. The cinnabar moth with its red and black bold markings is not touched by birds . The central American poison frogs have bright patterns on the body and its poison is used for arrow tips. Wasps too are brightly coloured. Some animals mimic the warning colours of other animals to avoid being hunted . A cinnabar moth caterpillar mimics a wasp's colouring and a hoverfly, too, mimics a wasp to escape being hunted by birds.

T he caterpillar changes into a butterfly by a very amazing process known as metamorphosis . When a young butterfly hatches from its egg, it is a long, worm shaped creature known as caterpillar. It spends its life time by feeding and growing . It is an avid eater of plant material and keeps on moulting or shedding its skin several times to grow. When it sheds its last skin , it forms a hard case around itself and is known as a chrysalis or pupa. Inside the pupa, the creature's body undergoes dramatic changes. Finally, an adult butterfly emerges from the case, stretches its crumpled wings and flies away.

J ellyfish along with sea-anemones and corals belong to the animal group called Scyphozoa and are also known as 'nettle animals '. A jellyfish is a large umbrella like bag with tentacles hanging below it. The tentacles have tiny stinging cells which are used to capture, paralyze and kill the prey while the bag keeps the animal floating. This floating stage is the adult stage of jellyfish and is known as the medusa stage . The eggs of the adult stage develop into polyps which attach themselves to a rock in water and feed and grow into the medusa. Jellyfish range in size from smaller than the tip of our finger to giants measuring two metres across. The largest jellyfish , Cyanea Capillata can grow to 2.3 m across and has tentacles hanging down to over 4 m.

T he Komodo dragon is the largest lizard in the world and belongs to the family of monitor lizards. Komodo is, in fact, the largest land lizard to have ever existed on the earth and can measure up to three metres long. They inhabit only the island of Komodo and the neighbouring Indonesian islands. The dragon hunts wild pigs, deer and monkeys and also scavenges on carrion. Young Komodo dragons catch insects and small mammals. Which Birds are the Fastest Fliers? Swifts are among the fastest flying birds. The spine tailed swifts of eastern Asia are the fastest known birds

S wifts are among the fastest flying birds. The spine tailed swifts of eastern Asia are the fastest known birds which have been timed at over 200 km/h in level flight. Swifts catch insects while flying, swooping through swarms of insects with their gaping mouth, wide open. They often fly throughout the night without landing. Other fast fliers include peregrine falcons, swallows and homing pigeons. Peregrine falcons can chase their prey in level flight at 60 km/h and are known to exceed this speed when stooping or diving on prey. Swallows are believed to reach 160 km/h while migrating and homing pigeons can generate speed up to 80 km/h.

F lowers have male and female organs, i.e., anther and stigma, and they perform the function of producing seeds. The transfer of pollen from an anther to a stigma is known as pollination and is the first stage in the reproduction of plants. The flowers, in many cases, are pollinated by insects and to attract the insects , flowers have bright colours and often produce sweet scent and nectar. The flowers have bright colours to attract the insects. While drinking the nectar of the flower, an insect picks up pollen on its body and when it visits another flower, it brushes some of this pollen on to the stigma , thereby making cross pollination. Insect pollinated flowers are usually blue , yellow, pink or white. In some regions, birds, bats, rodents and marsupials help in pollinating flowers. These flowers too, are very brightly coloured.

T o attract insects for pollination, some plants have adopted a unique strategy. Instead of having sweet smelling flowers, they have ones stinking with rotten smell. This attracts many pollinating flies. The lords and ladies plant emit rotten smell from its spike that sticks out of the top. Flies get attracted by this stinking smell and fall inside the sheath. They pollinate the female flowers with the pollen brought from other plants and are then showered with pollen from this flower. The world's largest flower Rafflesia also attracts insects by it's stinking smell and dark red, brown petals.

B ladder worts are plants that generally grow in water, which is poor in nutrients . They. obtain nutrition in a very unique way by trapping insects and digesting them to overcome malnutrition to survive. They are often rootless plants with only the flower spikes above the water and the leaves bearing the trapping organs or the bladders. The bladders are hollow bags borne at the end of a stalk with a small entrance at one end and have projecting bristles. This gives it an appearance of a crustacean and so small crustaceans like water flea, come to it for protection. The trap gets ready by pumping out water and creating a vacuum inside. As soon as an insect touches the bristle, the trap door opens and water gushes in along with the animal. The animal dies which is then digested upon by glands in the bladder.

T o keep plant-eating animals away, the whistling thorn bush has an armoury of sharp thorns. However, it is a home to virulent ants which keep off plant eating insects. They live in large swollen bulbs that develop at the bases of thorns. They attack in hordes by biting and stinging if any browsing animal dares to venture near the plant to try and eat leaves. They also keep a check on caterpillars , aphids and other plant eating animals and are, in return, rewarded by the plant. They feed upon the fruits growing on leaf tips and also get a sugary drink from the leafstalks.

C rabs belong to the animal group, crustacean that inhabits oceans. The robber crab or the coconut crab inhabiting the Andaman islands, are adept tree climbers. They are well adapted for living on land and will drown if left in water for a day. However, their larvae live in the sea. They are expert tree climbers and they pluck off the coconut, open and eat it with their powerful limbs. However, they are mainly carrion eaters and feed on dead animal matter that is washed up on the beaches.

A n orchestra is a large group of musicians who play together. The word orcestra once meant ' dancin lace'. In ancient Greek theatres, dancer and musicians performed on a space between the audience and the stage. When Italy invented opera, Italian theatres arranged their musicians in the same way. Eventually the word, orchestra was used to describe the group of musicians and not the place where they performed. In the 18th century Germany, the composers began to write music for four basic group of instruments of the Orchestra. These were the woodwinds (flutes , oboes and bassoons), brass (horns and trumpets), percussion (kettle drums) and strings (violins, violas, cellos and double bass). These groups of instruments are still the basis of the modern symphony orchestra.

L ike any other living organism, plants also breathe. They take in oxygen and release carbon dioxide by the process of respiration. The oxygen taken in is used for breaking down sugars that the plant makes during photosynthesis, and energy and carbon dioxide are released. This energy is used by plant for its growth and reproduction. About 40 per cent of the energy released is used up and the rest is lost as heat.

M istletoe is a plant which grows on branches of higher trees. It is a partial parasite since it has green leaves containing chlorophyll and can make its own food by photosynthesis. It takes the water and minerals it needs from the sapwood of the host tree. It is found growing on trees like apple, hawthorn, willow, poplar and lime . The seeds of mistletoe are spread by birds and once the seed germinates on the host tree, it develops haustorium . The haustorium is a tough structure and ensures of a regular supply of water and nutrients from the sapwood of the host to the mistletoe. The plant then develops a clamp like structure on the tree to be placed firmly.