Category Biology

How do bees make honey?

          Like us the bees also have colonies. No other class of wild species can match their organized way of life. The honey-bee colony consists of three main divisions: the workers, who provide food and protection for the colony; the queen who lays eggs, and the drones, who mate with the queen. An average honey beehive contains one queen, 100 drones and 60,000 workers. The workers are female bees while drones are male. The queen bee lays more than 2,000 eggs in a day, and about 250,000 eggs in a season, it lays more than 1,000,000 eggs in its lifetime. Most of the bees live for one to two years. One bee colony can have a grouping of up to 60,000 bees. The worker bees have many duties. In the beginning they clean and polish the hives. After some days, they look after the larvae of the bees. Eventually, they go out to collect the nectar from flowers. Do you know how these bees make honey?

          In fact, honey is the food of these bees. As such, for the bees, making of honey is like gathering food for themselves. And this they collect from flowers. The flowers contain a sweet liquid called the nectar. The bees drink this nectar and carry it to the beehive in their honey sacs. A bee must visit about 1000 flowers to fill its honey sac. The honey sac is located near the belly of the bee. A valve separates it from the belly. The sugar present in the nectar undergoes a chemical reaction. The water present in the nectar evaporates. And after this evaporation the honey can remain in the hive for a very long time without getting spoiled. This honey is stored as the food for future.

          There are many ways of extracting honey from the hive. The comb can be squeezed to yield honey. A machine is also available for removing honey from the combs. It is called the ‘honey extractor’. The colour and taste of various kinds of honey vary depending upon the flowers from which the nectar has been collected. Honey contains many substances which include two kinds of sugar-laevulose and dextrose, maltose, dextrins, minerals, enzymes, many vitamins, small amounts of proteins and acids. That is why honey is very useful for our health and fitness. 

Do some plants eat insects?

               You will be surprised to know that there are some plants which catch and eat insects. Such plants are called insectivorous plants. Since they cannot prepare their own protein, they get it by eating insects and worms. Every plant of this kind uses it own technique for capturing insects. The leaves of these specialized plants are adapted to trap and digest insects – which supplement their food supply.

               One of the famous insectivorous plants is ‘pitcher plant’. The upper part of its leaf resembles a small pitcher. Its colour is very attractive. It contains a sticky liquid. The opening of the pitcher has small fibres which allow the insects to go inside but obstruct their coming out. On being attracted by the beautiful colour, when some insect enters this pitcher, it is unable to come out. It gets entangled in the juice of the pitcher and the plant produces certain enzymes and digests it. The ‘cobra plant’ of America which appears like a snake, also eats insects. It also has pitcher-shaped mouth.

               The ‘sundew plants’ have hair on their leaves. The tips of these hairs have droplets of a liquid which appear very attractive. As soon as some insect is attracted towards a leaf, these hairs bend forward, capture the insect and digest it with the help of their own juice. The digested flesh is absorbed through their leaves. After that the hairs again become normal.

               There is a plant called ‘venus-fly trap’ which is found in America. Its leaves have beautiful red coloured elevations on both sides. Whenever an insect sits on a leaf it closes like a fork and the plant digests the trapped insect by digestive juices. The ‘uticularia’ is a water plant. It is found all over the world. The roots of this plant which are submerged in water have bulbous bladders. When some aquatic insects enter the bladder, the hairs on its opening do not allow it to come out. The walls of these bladders give out digestive juices which suck the proteins out of the bodies of these small insects.

Similarly, a plant called ‘Indian pipe’ is found in the hills of Shimla. It also eats insects. In addition to these, there are many other insectivorous plants all over the world.

 

Why can’t animals talk like us?

            In many stories it is told that animals can talk like us. But this is our imagination only. Amongst all the living beings, man is the only creature on earth who can communicate with the help of words or speech. This is because of the higher development of our brain. Because of a less developed brain, animals have not been able to originate words or a language to express their feelings. Hence they can’t talk like we do.

            It is a well-established fact that the animals too feel happiness, sorrow, fear, love, affection, hostility, hunger, thirst or protective needs etc. as humans do. Because they are incapable of expressing their feelings in words, they express or communicate to each other or to humans, with the help of certain gestures and sounds, which may or may not be familiar or understood by us. You might have seen when a cat goes near a group of birds, all the birds start chirping very loudly in a peculiar way. They actually express their fear that they may be caught by the cat. Similarly a dog expresses its anger by barking and its feelings of flattery by wagging its tail. A monkey demonstrates its anger by making peculiar sounds.

 

How is bark formed?

              Bark is the protective outer covering of tree branches, trunks and roots. Bark has three layers. The outer layer called periderm is made of dead cells, such as cork. Periderm is usually thick. It protects the tree against weather, insects and diseases. The middle cortex layer is made of living, non growing cells. The innermost phloem brings food made in the leaves, down to the roots. The periderm of some trees has small openings called lenticels. Lenticels allow gases such as oxygen and carbon dioxide to enter and leave the plant.

             As wood is laid down inside a shoot, a layer of cells near the outer side begins to divide and produce cork cells. The walls of these cells soon get heavily thickened with a waterproof substance. The cells die and form bark.

           Over the years the bark is constantly added to form the inside of the tree. So as the diameter of the twig, branch or trunk increases, the waterproof barrier is maintained. But the outer bark often splits and cracks or becomes flaky.

           As already mentioned, the bark protects a tree from the weather and sudden temperature changes. It contains substances that repel insects and resist fire. Bark often has commercial uses. The actual cork comes from the bark of the Mediterranean cork oak. The drug Quinine is obtained from the bark of Cinchona trees and Cinnamon comes from the bark of the Cinnamon tree. Cough medicines and many other useful substances are also obtained from the bark.  

 

How do plants take and make their food?

            It is a well-known fact that trees and plants are also living beings like humans. They need food, water and air for survival. It is interesting to know how they take their food.

            Plants derive their food both from the earth and the air. If you minutely look at their roots, you will find that the ends of these roots are like fine fibres. We call them root-hairs. They absorb water and minerals and transport them upwards to the leaves through the trunk and the branches. It is the leaves which prepare the food.

            The leaves have pores which are filled with air. They also have a green colouring matter called chlorophyll. This chlorophyll acts as a catalyst, and uses carbon of the carbon dioxide and the hydrogen of the water present in the leaves to make carbohydrates (sugars). In this process oxygen and water are given out which are excreted by the leaves of plants.

            Sugar is further converted into starch. From these carbohydrates, the plant can build up complex substances as foods which it needs for its life and growth. These substances include proteins, juices, oils (fats) etc. The water from which the plants take hydrogen for photosynthesis contains dissolved minerals needed in building various parts of the plant body. These are chiefly the compounds of nitrogen, sulphur, phosphorous, sodium, calcium, magnesium, iron etc.

            Food not immediately needed for growth is stored in the plant including its seeds, fruits, tubers or bulbs. This accumulated food in the seed is used in its germination.

 

How do animals and pants survive in deserts?

            Due to the scarcity of water and particular climatic conditions (hot, dry, windy) prevailing in the desert, it is very difficult for animals as well as plants to survive. Nonetheless, we do find some of these. These are adapted to the desert conditions. Let us see what types of vegetation and animals are found there and how do they survive.

           The vegetation of a desert is mainly thorny shrubs, cacti and palm (especially date) trees. Cacti and other desert plants have adapted themselves to live in desert conditions. They have evolved ways to store water in their fleshy stems. The leaves have squeezed themselves into tiny thorns to reduce the loss of water. The roots go deep into the ground and are wide spread to collect every drop of water available. The stem stores the water and slowly gets thinner as the water gets used up. In some cacti the thorns are pointed towards the earth. The dew drops deposited on the ends fall on the earth hence moisture is maintained below the cacti. There are quite a few animals found in deserts such as snails, pack rat, jerboa, etc. Most desert animals sleep during the day to escape the day temperature and they come out in night in search of food. Some animals sleep during the hottest part of the year. Animals such as kangaroo, rat and gerbil can survive with little or no water. Reptiles adjust their body temperatures to cope with heat and cold. The Australian desert toad stores water in its body. Some lizards, ants, owls and snakes also live in deserts.