Application of Biology – The knowledge of biology is playing very important role in the welfare of human beings. Advance studies in biology especially genetic engineering, plant and animal breeding and biotechnology have n flounced man’s economic, social and industrial progress. They have enabled man to develop high yielding crops, better strains of livestock and many other developments beneficial to man. They are proving helpful in meeting the demands of rapidly growing population. Some of the contributions of biology in the economic development of various aspects of human life are given below:
Forestry, fuel, furniture
Forestry is the business of cultivating trees which provide us fuel, timber and wood products. Timber is used for making furniture. Paper industry is also dependent upon wood. Turpentine and resins are extracted from many of the trees.
Advancement in biology has helped forest cultivators in choosing trees that fit successfully in local habitat. Modern plant breeding techniques have developed various varieties of plants that can tolerate wide range of climatic conditions and are fast growing, in addition to being of high productivity, palatability and nutritional content. So forest cultivators select varieties which satisfy all their requirements.
Agriculture
Food and clothing are basic necessities of mankind. With the increase of population man thought of securing more food by cultivating the most desirable plants and domesticating animal breeds. Application of the biological knowledge has enabled scientists to increases yield of crops and to improve quality of fruits and vegetables. In agriculture, cereal crops like wheat, corn, rice have been selectively cultivated and crossed with other varieties to produce super strains capable of giving a palatable high yielding crop in a minimal amount of time. Disease and pest resistant varieties have been evolved by plant breeders.
Plant breeding and selective cultivation has also enabled agriculturists to improve the yield of soyabean, sugarcane, maize, potatoes and almost all other crops and fruits. Biological knowledge has also led to increase in production by the use of fertilizers, better methods of cultivation and crop rotation.
A breed is a collection of individuals within a species which are evolved by selective mating for some definite set of qualities.
Dairy, poultry and fish farming
Biology is playing very important role in the economic development, in the field of poultry, dairy and fish farming. By the use of animal breeding technology, cross breeds of different animals have been raised which provide better protein source in the form f meat and high milk production in the case of cattle, eggs and meat production in the case of poultry and wool & meat in the case of sheep. The cross breeds are more resistant to disease and are more vigorous (fig 20.4).
Biology is helping to know more about diseases and their cure by studying various disease causing agents like viruses, bacteria and other parasites.
Biological knowledge helps in the development of balanced diet for different animals which is necessary for their rapid and speedy growth. Ideal feed is that which has better food conversion ratio.
Fig. 20. 4: A prize bull-the result of improved cross-breeding
Sericulture
Application of Biology – Sericulture is the production of silk by the activity of worms known as silk worms. This process of rearing silk worms had been crude and laborious and often various diseases of silk worn wipe out all cocoons. Biological knowledge has enabled the farmers to overcome these and many other problems associated with sericulture.
Adult silk moth female lays eggs, which hatch in three to four days. Young larvae feed on buds and new shoots of mulberry. They grow in size and when fully-grown, silk worm larvae stop feeding and spin a continuous silk thread around it forming a cocoon. After few days cocoons are placed in hot water to kill the pupa. Workers then pick up one end of the thread and pass it over a reeling machine. These strands are then passed on machine to produce the fabric biologist have helped, making revolutionary progress in this field.
Japanese biologists have developed a wingless variety of silk moth which is easy to handle. Some varieties which complete 5-6 life cycles in a year have been raised.
Apiculture
Domesticating the honeybee for the honey production is known as apiculture. Honeybee is a social insect and lives in large colonies. Honeybees are trimorphic, consisting of queen, drones and workers. The queen bee is larger than the rest and is protected and fed by the workers. It is meant for egg laying. Workers collect nectar and pollen making honey, secrete wax, protect and feed the queen. Drones are male and their function is to fertilize the eggs and they no role in honey formation. Biological knowledge has led to a better understanding of usefulness of honeybees. Some varieties of domestic honeybees have been imported and their new breeds have been raised by the biologist in Pakistan.
Pests and their biological control
A large number of organisms damage useful plants and animals causing server damage to our economy and even to livestock and public health. Such destructive organisms (insects etc) are called pests. There are many methods to control the pests: e.g.
- Primary or cultural control: crop rotation should be used instead of mono cultures i.e. palting of only single-species crops again and again.
- Chemical control: chemicals like DDT are used as insecticide. Insects have developed DDT resistant strains. These insecticides also increase the toxicity and pollution, thus their use is now being discouraged.
- Biological control: biological control is the most promising pest control method. The method utilizes natural enemies like predators, parasites and pathogens of pests to control and destroy the pests (Fig 20.5).
Fig. 20. 5:biological controls of pests –here lady bugs are being used to control cottony cushion scale insect on citrus tree.
Advantages of biological control method
- They do not pollute the environment
- They do not disrupt and disturb the natural ecosystem.
- They usually provide permanent control of pest population, because pests rarely develop resistance to natural control.
Currently in some developed countries lace wings and lady beetles (predatory insects that feed on a variety of other pest insects) are raised commercially. Lace wings are much effective for controlling ball worm population in cotton fields. Recently certain pest pathogenic viruses have also been proved effective in controlling cotton ball worm and corn ear worm.
Pest pathogenic bacteria are also of great importance in this respect. Spores and toxins of the bacterium bacillus thuringiensis are sprayed on leaves, vegetables and flowers. They infect and kill the larvae of at least twenty species of butterflies and moths.