Botany

          The age-old maxim, ‘An apple a day keeps the doctor away’ was a polite way of saying that this habit would help to prevent constipation and other related ailments. Since it was believed that the juice of a raw apple aided the fermentation of undigested foods.

          Although one might question such a sweeping statement in the highly advanced modern times, none can deny that apples are good for health because of their high nutritious value. Some people have modified this statement and suggested that ‘it keeps the dentist away more than the doctor’. According to the dentists, biting on a crisp apple is an effective way of removing food particles from between the teeth. Eating an apple after meals and cleaning the teeth in the night and morning is the best way to keep the teeth healthy. 

          Apples contain Vitamins A and C. They are rich in cellulose and carbohydrates. They also contain some minerals. This implies that apples also help in the prevention and cure of several deficiency disorders, e.g. scurvy, night blindness etc. as well as in purifying blood. They also aid in healing, protection against cold and building of healthy bones, teeth and gums.

          The presence of these food sources and their utility in keeping the body fit and healthy justifies the old adage.

          Apples are eaten raw, both for taste as well as its beneficial values. An apple contains about five-sixths water and the remaining one-sixth consists of sugar, ascorbic acid (Vitamin C) and other acids, and rough indigestible matter. Apart from their nutritious value, apples are also used for cooking sweet dishes, and cider is brewed from fermented apples.

          Apples belong to the family of Rosaceae. In the ripen state they are usually red, yellow or green. Apples grow in temperate zones, in relatively cold weather. By the end of 300 A.D, a Roman writer named 37 varieties of apple and today hundreds of varieties are available with varying sweetness. 

          A rain forest is a warm and rainy place with a thick growth of trees. Because of heavy rains, the trees grow tall and close together. The tree tops are so thickly branched that they almost block the passage of the wind. The air is still and uncomfortable. The thick tree top also prevents sunlight from reaching the ground. It is difficult to walk through these areas. Along with a large number of trees, it also has many different kinds of animals. These include noisy birds, hungry crocodiles, lizards, snakes and jaguars. Thousands of insects of different types are also found in the rain forests. There is an ant called ‘army ant’     that eats anything that would not move out of its way. There are certain mosquitoes whose bite is fatal; sweat bees which crawl into people’s ears and noses, and ticks and flies bite their skin.

          Most rain forests are located near the equator. The largest rain forest is the Amazon basin in South America. The temperature ranges from about 20 to 34°C. Thunderstorms occur about every three days. Areas of rain forests experience heavy rains upto 250 cms (100 inches). The tallest trees of rain forest form a covering of leaves called the upper canopy. The upper canopy may be 30 to 46 m above the ground. Smaller trees form lower canopies. The shade from the trees prevents about 99 percent of the sunlight from reaching the ground. Thus there is not much plant life on the forest floor. Dense vegetation close to the ground occurs in clearings and along rivers. These areas are sometimes called jungles.

          There are different kinds of plant and animal life in rain forests. Tropical rain forests contain the greatest variety of wild life including the wealth of insect life. Many of these insects have wonderful forms of camouflage. Also more different species of trees are found in tropical rain forests than in any other kinds of forests in the world. The soil layer in the tropical rain forests is very good for farming. 

            Any plant or animal that occurs in such abundance as to pose a distinct threat to man or his interests is called a pest. And the chemicals used for mitigation, control or elimination of such plants or animals are known as pesticides. Today we have algaecides, defoliants, herbicides, plant growth regulators and fungicides in use to control the growth of undesirable plants which compete with crops or other useful plants. Attractants, insecticides, miticides or acaricides, molluscicides, nematocides, repellents and rodenticides are used to reduce parasitism and disease-transmitting organisms in animals, crops, plants, foods, textiles and human beings.

            Most of the pesticides are chemical compounds and act in a similar fashion, i.e. by blocking some metabolic process. They, however, differ in composition, potency, mode of action, speed of effect. So different pesticides are used at different stages of infection.