NCERT Solutions for Class 12 Biology Chapter 9 Strategies for Enhancement in Food Production
These Solutions are part of NCERT Solutions for Class 12 Biology. Here we have given NCERT Solutions for Class 12 Biology Chapter 9 Strategies for Enhancement in Food Production
Explain in brief the role of animal husbandry in human welfare.
Animal husbandry is the practice of taking care of and breeding domestic animals by applying scientific principles. Good animal husbandry practices meet the ever- increasing demand of food from animals and animal products both in terms of quality and quantity.
Role of animal husbandry in human welfare is discussed as follows:
- Milk is an important product of farm animals that is consumed as such, in the form of curd, cheese, butter, ice cream, etc. Milk is the only source of animal protein for vegetarians and is a complete food. Most of the milk is obtained from cow and buffalo. Other milk yielding animals are goat, sheep, camel and yak.
- Egg, like milk, is also a complete food. Chicken and duck are the two major sources of egg.
- Meat is a protein rich diet that is obtained from all types of livestock, e.g., goat, sheep, pig, cattle, chicken, fish, etc.
- Honey is a sweet syrup obtained from hives of honey bee. Honey is used in sweetening various preparations.
- Fibres like wool and silk are two high quality fibres which we get from animals. Wool is hair of sheep, some goats and rabbits. Silk is a product of silkworm.
- The skins of many animals are converted into hides and leather.
- Drought animals are trained to carry men and materials besides other functions, e.g., buffalo, bullock, horse, camel, ass, elephant, reindeer, yak.
- Rearing of animals provides employment to many persons.
- Animal byproducts like horns, feathers, bone, dung and droppings are all used in developing useful products.
If your family owned a dairy farm, what measures would you undertake to improve the quality and quantity of milk production ?
Some of the measures to be followed for proper management of dairy farm are :
- Selection of good breeds having high milk yielding potential according to the climatic conditions of the area.
- The shed under which the cattle are kept should be well ventilated with adequate water supply for drinking as well as for washing. Shed should have pucca floor and proper drainage channel.
- The feed of the animals should be a balanced diet with right proportions of carbohydrates, fats, proteins and roughage and it should be given timely in good quantity.
- Cleanliness and hygiene comes first for maintaining the livestock’s healthy and productive. So, washing cattle’s and taking precautionary measures while milking are must.
- Inspection, keeping records of the activities and consulting a veterinary doctor for regular check ups of the livestock’s should be undertaken.
What is meant by the term ‘breed’? What are the objectives of animal breeding?
A group of animals which are related by descent to each other and possess similar characteristics like appearance, size, features etc. are said to belong to a breed. The purpose of animal breeding is to produce animals with increased yield, faster growth, improved reproductive rate.
Name the methods employed in animal breeding. According to you which of the methods is best ? Why ?
Animal breeding is producing improved breeds of domesticated animals by improving their genotypes through selective mating. There are two methods of animal breeding, natural breeding which includes inbreeding, out-breeding , cross breeding, out-crossing, etc. and artificial breeding which involves artificial insemination and multiple ovulation embryo transfer technology (MOET). It involves inseminating the native cows with the semen of superior bulls of exotic or indigenous breeds. Artificial breeding is the best method of breeding because of the following reasons:
- Semen collected from male may be used immediately or can be frozen and used later.
- Semen of desired bulls is collected under hygienic conditions, preserved and sent to all insemination centres throughout the country.
- Semen collected from one bull can be used to inseminate many cows as fewer sperms are required to achieve conception, when semen is deposited artificially. Hence, artificial insemination is very economical.
- It is healthier as the spread of sexually transmitted diseases can be controlled by this technique.
What is apiculture ? How is it important in our lives ?
Apiculture also known as bee keeping is the management of honey bees for the production of honey and wax.
Apiculture is important in our lives in many ways :
- Honey is sweet and edible and is of high nutritional value containing sugar, water, minerals, amino acids, vitamins, enzymes and pollen.
- It has a great medicinal value and is used in making various medicines. It is used for treatment of disorders related to digestion, dysentery, vomiting, stomach and liver ailments.
- A drug, prepared from the bodies of honey bees, is used in the treatment of diphtheria and some other dangerous diseases. The venom of honey bees is used in the treatment of arthritis and snake bite.
- The bee wax obtained from the hives is used for preparing cosmetics and polishes in many industries.
Discuss the role of fishery in enhancement of food production.
Fishery is the rearing, breeding, catching & marketing of fishes and other aquatic animals. Fishes are important food for a large portion of human population. Meat of fishes is a rich source of proteins and other useful substances like polyunsaturated fatty acids (PUFA). The meat of other aquatic animals like prawn, crab is also consumed as food by human beings.
Briefly describe various steps involved in plant breeding.
Plant breeding is the purposeful manipulation of a plant by crossing different varieties in order to create desired plant types that are better suited for cultivation, give better yields and are disease resistant.
Plant breeding involves the following steps :
1. Collection of germplasm – Collection and preservation of all the different wild varieties, species and relatives of the cultivated species. The entire collection
(of plant/seeds) having all the diverse alleles for all genes in a given crop is called germplasm collection.
2. Evaluation and selection of parents – The germplasm is evaluated so as to identify plants with desirable combination of characters.
(a) Selection in self-pollinated crops- There is repeated self-pollination of selected plants till superior homozygous genotypes are obtained. The best one is used as new variety. The self-pollinated progeny of homozygous plant constitutes a pure line.
(b) Selection in cross-pollinated crops- The cross-pollinated crops are heterozygous for most of their genes and their population contains plants of several different genotypes. Superior genotype plants are selected and are allowed to cross breed (these plants are not allowed to self breed) so that heterozygosity is maintained
3. Cross hybridisation among the selected parents – Hybridization is crossing of two or more types of plants for bringing their traits together in the progeny. The procedure of hybridisation involves selection of parents with desired characters, selfing, emasculation, bagging, tagging and artificial pollination.
4. Selection and testing of superior recombinants – This is the selection of the plants, from the progeny of hybrids, which have the desired combined character. The selected plants are then self-pollinated for several generations to get a uniformity i.e. homozygosity.
5. Testing, release and commercialisation of new cultivars – The newly selected lines are evaluated for their yield and other agronomic traits of quality, disease resistance etc. These selected cultivars are then tested with local best cultivar and then are released for commercialisation.
Explain what is meant by biofortification.
Biofortification is method of breeding crops with higher levels of vitamins and minerals, or higher proteins and healthier fats in the view to improve public health. E.g., iron fortified rice containing five times more iron then other varieties, wheat variety, Atlas 66 having high protein content, maize varieties having high lysine and tryptophan are produced.
Which part of the plant is best suited for making virus-free plants and why?
The apical or axillary meristems are best suited for making virus free plants because they are generally free from virus.
What is the major advantage of producing plants by micropropagation?
Micropropagation is the tissue culture technique used for rapid vegetative multiplication of ornamental plants and fruit trees by using small sized explants. Because of minute size of the propagules in the culture, the propagation technique is named as micropropagation. This method of tissue culture produces several plants. Each of these plants will be genetically identical to the original plant from which explants were taken. Plants obtained by vegetative propagation of a single plant constitute a somaclone. The members of a single somaclone have the same genotype. It is the only process adopted by Indian plant biotechnologists in different industries mainly for the commercial production of ornamental plants like lily, orchids, Eucalyptus, Cinchona, blueberry, etc., and fruit trees like tomato, apple, banana, grapes, potato, Citrus, palm, etc.
Find out what the various components of the medium used for propagation of an explant in vitro are.
The culture medium used for the propagation of an explant in vitro contains nutrients like inorganic salts, vitamins, 2-4% sucrose, amino acid glycine and growth regulators like auxin and cytokinin with or without the use of yeast extract or coconut milk or banana pulp. The culture medium can be kept liquid, made semisolid with gelatin or solidified with agar. These nutrients are required by the explant for growth and development.
Name any five hybrid varieties of crop plants which have been developed in India.
Some of the hybrid varieties of plants in India are :
- Himgiri (wheat) – Resistant to leaf and stripe rust, hill bunt
- Pusa Gaurav (mustard) – Resistant to aphids
- Pusa Komal (cowpea) – Resistant to bacterial blight
- Pusa Sadabahar (chilli) – Resistant to chilli mosaic virus, TMV and leaf curl.
- Jay a and Ratna (rice) – High yielding semi-dwarf varieties
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