Category Science

Is Bamboo a tree or grass?

             Majority of people believe bamboo to be a kind of shrub or plant. In fact, it is neither. It is a type of grass. It can reach a height of about 35 metres and upto a thickness of about 30 cm. It has many varieties. About 600 species of bamboo have been studied. All kinds of bamboos have smooth, hard and strong trunks. The rate of their growth is very fast. It can grow up at the rate of 40 cm a day. One bamboo reportedly grew 90 cm in 24 hours. Some bamboos blossom only once in 30 years. Others may take 100 years to blossom. A bamboo plant dies after it blooms. The seeds from these blossoms grow into new plants.

            It is only the stem of the bamboo grass that is of most use in the construction of roofs, huts, walls, houses, etc. It is used to make mats, baskets, musical pipes, paper, as a fishing rod and weapon for defence; it is cooked as vegetable and pickle is also made of them; some medicines are made from a fluid in the stem joints of bamboo branches. Its hollowed stems are used as water pipes especially in Japan.

            It is found in abundance in South-East Asia, Indian subcontinent and the islands of the Pacific Ocean.

 

What is regeneration?

Would it not be wonderful if people who lost an arm or a leg or even a finger in an accident could simply grow another one in its place? But in reality it does not happen so in case of human beings. However, you will be surprised to know that there are some living beings in which a new limb develops at the same point from where the original limb has been lost. Development of a new body part in place of a lost one is known as regeneration.

If a small arm of a starfish is cut off or destroyed, it is regenerated. The hydra, lizards, sponges, newts and earthworm also possess this capability of regeneration.

The ability of regeneration is different in different creatures. Living beings with complicated structures have lesser ability of regeneration. Man and other mammals have a complex constitution. That is why they have lesser ability of regeneration. Mammals can replace hair, nails and skin. Mammals can also repair broken bones and other damaged tissues. Regrowing of the wings of birds is another example of regeneration.

In some species new tissues grow from the surface of the wound replacing the lost or damaged tissues. Sometimes, the tissues that an organism regenerates are different from the original ones. The regenerated structure may be smaller and weaker than the original one.  

What are bacteria?

               Bacteria belong to the lowest category of plants. They are unicellular micro-organisms. They are as small as 25,000th part of an inch. Some of them are even smaller and cannot be seen with the help of an ordinary microscope. They reproduce through the process of cell division (fission) i.e. one cell divides itself into two. Under favourable circumstances the rate of their reproduction increases. Within twenty minutes the cells of the new bacterium divide into two, in forty minutes one bacterium multiplies to four and to sixty four in two hours. In this way, in twenty-four hours, one bacterium multiplies into 4,000,000,000,000 bacteria. If the rate of the reproduction of bacteria remains the same, the weight of the bacteria produced within 72 hours will become 33,000 times more than the weight of the earth. But this is impossible because in the struggle for food and water only one percent of them can survive. They may live in soil, water, air or in any other organisms.

               Bacteria can be broadly classified into four types. Some bacteria are round, they are called coccus. The rod-shaped are called bacillus, spiral-shaped the spirillum and the comma-shaped vibrio.

               Bacteria are both harmful and useful. They spread many diseases in human beings, animals and plants. Typhoid, tetanus, T.B., cholera, diphtheria, dysentery, whooping cough etc. are some of the well-known diseases which are spread by bacteria. But, on the other hand, some bacteria are very useful for mankind. Conversion of milk into curd is done by bacteria. They destroy the dead plants and animals by setting decay in them. Vinegar is also prepared by them. It is the bacteria which make yeast for bread, and colours the hides (animal skin). Certain antibiotics are also prepared by using them. Thus, bacteria are both useful and harmful to us. Antibiotics and sulpha drugs are used to control bacterial diseases. 

 

What is Fungus?

 

 

 

 

 

 

 

              In rainy season, you must have seen the growth of soft, white, cottony and velvety patches of mould on stale bread, pickles, damp cloth, leather, food, leaves, fruits and vegetables. These are called fungi and are classified flowerless plants having no roots, no stems and no leaves and are without chlorophyll – the green colouring matter. Due to the lack of chlorophyll, fungi depend for their food either on a living organism (parasite) or on the dead organic matter (saprophyte). When we examine the fungi under a microscope, we see that they consist of a large number of black, green, yellow or blue fibres. These fibres have two parts – one part is mycelium which spreads like roots and takes food from the material on which it grows. The other part is round, ball-like lymph, which contains spores. Always present in the air, they start multiplying whenever they get bread, fruits and other eatables in hot and humid places.

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What is a Virus?

                Viruses are micro organisms which cause various diseases in all types of living bodies, so much so that even bacteria are affected by viruses. There is a helpful virus called bacteriophage which eats bacteria and can not be seen by necked eye. One can only see them with the help of an electron or ultra microscope. Strangely enough, viruses are considered both as living and non-living objects. They grow and multiply in living cells and therefore are treated as living organisms. Since they do not grow outside living cells. They are classified as non-living objects also. Consequently, they are treated on the border line of living and non-living matter.

                  Viruses were first discovered by Mayer in 1888. He found them on tobacco leaves. There are many kinds of viruses. They are of varying shapes and sizes. Some are long as rods, some are hexagonal. The smallest viruses are of the size of a millionth part of an inch. They are found in the cells of plants, animals and human beings. They are born in these cells, multiply there and spread diseases.

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How far can a Kangaroo jump?

              Kangaroos are marsupials (animals with pouches) that live in Australia and New Guinea. Most of them live on grassy plains and feed on plants. They move about in troops, springing along on their big, powerful hind legs and large feet. Their long tails help them to balance.

              There are five species of kangaroos. Red and grey ones are the largest. A red kangaroo may be taller and heavier than a man. Grey kangaroos can bounce along at 40 kilometres per hour if chased. Wallaroos are smaller kind of kangaroo.

              A full grown kangaroo stands about six feet tall. Its front legs are short while the hind legs are very long. The powerful hind legs enable the kangaroo to take long jumps of 3 to 5 metres at a time. If a hunter or hunting dog chases a kangaroo, it runs very fast making long jumps. It can cover a distance of 7 to 9 metres just in one jump. When a kangaroo is cornered by hunting dogs, it can seize a dog with its forelegs and kill it with one swing of its hind legs.

             The female kangaroo has a pouch in its belly in between the hind legs in which it keeps its young ones till they grow up. When a baby kangaroo is born, it is a tiny, pink, naked mass of about 2.5 cm in length and about 1 gm in weight. Not only the infant kangaroo, but even young kangaroos need the protection of their mothers. A kangaroo lives on the mother’s milk until it leaves the pouch at the age of 6 to 8 months. A kangaroo lives for about 6 to 8 years. Finding the young ones in danger, the mother kangaroo lifts them with its mouth and places them inside its pouch.

           The kangaroo is a mild animal like the sheep and goats. Like the hare, it is unable to see an object just in front of it. But its power of smelling and hearing is quite strong.