VBQs Strategies for Enhancement in Food Production Class 12 Biology with solutions has been provided below for standard students. We have provided chapter wise VBQ for Class 12 Biology with solutions. The following Strategies for Enhancement in Food Production Class 12 Biology value based questions with answers will come in your exams. Students should understand the concepts and learn the solved cased based VBQs provided below. This will help you to get better marks in class 12 examinations.
Strategies for Enhancement in Food Production VBQs Class 12 Biology
Very Short Answer Type Questions
Question. Suggest the breeding method most suitable for animals that are below average in milk productivity.
OR
Write professional approach at genetic level that can help the farmer to improve the milk yield of low milk producing cows on his farm.
Answer : Outcrossing or outbreeding or cross breeding is the most suitable breeding method for animal, that are below average in milk productivity.
Question. Write the name of the following :
(i) The most common species of bees suitable for apiculture.
(ii) An improved breed of chicken
Answer : (i) Apis indica / Apis mellifera / Apis dorsata
(ii) White Leghorn / Rhode Island Red / Minorca
Question. A herd of cattle is showing reduced fertility and productivity. Provide one reason and one suggestion to overcome this problem.
Answer : Reason : Inbreeding depression or continuous inbreeding.
Suggestion : Should be mated with unrelated superior cattle of the same breed or out – breeding or out – crossing.
Question. Which one of the following is used in apiculture :
Hilsa, Apis indica, Sonalika.
Answer : Apis indica.
Question. List any two economically important products for humans obtained from Apis indica.
Answer : (i) Honey (ii) Bee wax.
Short Answer Type Questions
Question. (i) Why is inbreeding necessary ? Give two reason.
(ii) What does continued inbreeding lead to ?
Answer : (i) Inbreeding is necessary if we want to evolve a pure line in any animal / plant.
(ii) Inbreeding exposes harmful recessive genes that are eliminated by selection leading to accumulation of superior genes. Continued inbreeding reduces fertility and productivity (Inbreeding depression).
Question. Success rate of artificial insemination in cattle is fairly low. Identify any other technique to improve the successful production of hybrids. State two advantages of this technique.
Answer : Multiple Ovulation Embryo Transfer Technology increases herd size, in a short time.
Detailed Answer :
Controlled breeding of cattle is carried out by artificial insemination but the success rate is low. This can be overcome by MOET (Multiple Ovulation Embryo Transfer) technique.
This techniques helps to improve the successful production of hybrids and also to increase the herd size.
Question. Explain inbreeding depression and how it can be overcome.
OR
How does inbreeding depression set in ? Mention the procedure you would suggest to reverse this.
Answer : Continuous inbreeding among cattle causes inbreeding depression. It decreases the fertility and productivity of an animal. It can be overcome by applying outbreeding, in which mating is done between different breeds or individuals of the same breed but having no common ancestors.
Outbreeding includes out-crossing, cross-breeding and interspecific hybridisation.
Question. What is outbreeding ? Mention any two ways it can be carried out.
Answer : Breeding of unrelated animals from the same breed having no common ancestors for 4 – 6 generations.
Outcrossing or cross breeding or interspecific hybridisation.
Detailed Answer :
Outbreeding is the breeding of the unrelated animals. It is of three types namely,
(i) Outcrossing
(ii) Cross – breeding
(iii) Inter – specific hybridization.
Question. How is pure line in an animal raised ? Explain.
Answer : Pure line :
(i) A pure line animal is raised through inbreeding. It is a progeny of single, self-fertilized homozygous individuals.
(ii) A similar strategy is used for developing pure lines in cattle as was used in case of peas. Inbreeding increases homozygosity. Thus, inbreeding exposes harmful recessive genes that are eliminated by selection.
(iii) It also helps in accumulation of superior genes and elimination of less desirable genes. The selection increases the productivity of inbred population.
Question. Differentiate between out-crossing and crossbreeding.
Answer :
| Out-crossing | Cross breeding |
| Mating of animals of same breed. | Superior males of one breed are mated with superior females of another breed. |
| No common ancestors on either side upto 4 – 6 generations | Progeny may have desirable characters of both parent |
| Helps to overcome inbreeding depression | Used for commercial production / obtaining improved characters |
Question. Explain how and why controlled breeding experiment is carried out in cattle.
Answer : Controlled breeding experiments are carried out using artificial insemination. Semen is collected from the male-chosen as parent, injected into the reproductive tract of the selected female (cow), stored semen may be used later to conduct desirable matings.
Helps overcome several problems of normal mating, improve the quality and quantity of desired yield.
Question. Enlist the steps involved in inbreeding of cattle. Suggest two disadvantages of this practice.
Answer : Inbreeding involves mating of closely related individuals within the same breed for 4-6 generations.
Superior males and superior females of the same breed are identified and mated in pairs, the progeny are evaluated, superior males and females among them are selected for further mating.
Disadvantages : Continued inbreeding causes inbreeding depression, reduction in fertility, reduction in productivity.
Question. (i) State the objective of animal breeding.
(ii) List the importance and limitation of inbreeding.
How can the limitations be overcome ?
(iii) Give an example of new breed each of cattle and poultry.
Answer : (i) Increases the yield of animal and improves the desirable qualities of the produce.
(ii) Importance :
(a) Increases homozygosity which is necessary to evolve pure line in any organism.
(b) helps to expose harmful recessive genes.
(c) helps in accumulation of superior genes.
Limitation :
Continuous inbreeding among cattle causes inbreeding depression. It decreases the fertility and even productivity of an animal. It can be overcome by applying outbreeding, in which mating is done between different breeds or individuals of the same breed but having no common ancestors. Outbreeding includes out-crossing, cross-breeding and interspecific hybridisation.
(iii) Jersey / Hisardale – a new breed by crossing Bikaneri ewes and Miranio rams (cattle) and white Leghorn (poultry).
Question. (i) What is the programme called that is involved in improving success rate of production of desired hybrid and herd size of cattle ?
(ii) Explain the method used for carrying this programme for cows.
Answer : (i) Multiple ovulation embryo transfer method / (MOET) is involved in improving success rate of production of desired hybrid and herd size of cattle.
(ii) High milk yielding cow administered hormone (with FSH like activity) → 6 to 8 eggs produced → inseminated artificially → fertilised eggs recovered non-surgically at 32 cell stage → transferred to surrogate mother for further growth.
Question. (i) Write the scientific name of the most common species of honey bee reared.
(ii) Mention the kind of areas that are suitable for bee keeping practices.
(iii) Mention any two uses of bee wax.
Answer : (i) Apis indica is the most common species.
(ii) Bee keeping can be practiced in any area where there are sufficient bee pastures of some wild shrubs, fruit orchards and cultivated crops.
(iii) Bee wax is used in cosmetics and medicines.
Question. Write the aim with which animal breeding programmes are carried. Describe the essential steps be followed in poultry management.
Answer : Aims – increasing the yield of animals, improving the desirable qualities of the produce.
Steps to be followed in Poultry Management :
(i) Selection of disease free and suitable breeds.
(ii) Proper and safe farm conditions.
(iii) Proper feed and water.
(iv) Proper hygiene and health care.
Detailed Answer :
The aim of the animal breeding programmes are to increase the animal yield and to improve the desirable qualities of the produce.
Essential steps to be followed in poultry Management are :
(i) Selection of disease free and suitable breeds.
(ii) Proper and safe farm conditions.
(iii) Proper feed and water.
(iv) Hygiene and health care of birds.
Question. State the objective with which a dairy farm is set up. Describe the essential steps to be followed for dairy farm management.
Answer : Processes and systems that increase yield and improve quality of milk
♦ Selection of good breeds having high yielding potential and resistance to diseases
♦ House to have adequate water and kept disease free
♦ Feeding in a scientific manner with quality fodder
♦ Storage and transport of milk and products
♦ Regular inspection with proper record keeping / Regular visits of veterinary doctor.
Long Answer Type Questions
Question. Explain the efforts which must be put in to improve health, hygiene and milk yield of cattle in dairy farm.
Answer : Following efforts must be put in mainly to improve health, hygiene and milk yield of cattle in dairy farm:
(i) The cattle should be housed well in well ventilated sheds with adequate water supply.
(ii) There must be cleanliness and hygiene of both the cattle as well as the handlers while milking and transport.
(iii) Regular visit by veterinary doctors must be ascertained so as to keep the cattle healthy and disease free.
(iv) Feeding should be carried out in a most scientific manner with special emphasis on quality and quantity of fodder and the hygienic conditions.
(v) Breeding is necessary for improving the milk yield.
(vi) Selection of high yielding and disease resistant breed should be arranged.
(vii) Regular inspection and keeping updated record of all the activities of dairy is necessary.
Question. (i) Name the technology that has helped the scientists to propagate on large scale the desired crops in short duration. List the steps carried out to propagate the crops by the said technique.
(ii) How are somatic hybrids obtained ?
Answer : (i) Tissue culture / micro propagation.
Explants are grown in a test-tube, under sterile condition, in special nutrient medium / culture medium.
(ii) Isolated single cells, digests cell walls, to obtain naked protoplast from two different varieties, fusion of protoplast.
Hybrid protoplasts thus, obtained are cultured in a suitable medium to form new plants.
Somatic hybridisation : (i) Isolation of protoplasts using enzymes pectinase and cellulase
(ii) Protoplasts fusion induced by PEG.
Question. What is somatic hybridization? Explain the various steps involved in the process. Mention any two uses of somatic hybridization.
Answer : The process of fusion of protoplast of somatic cells derived from different varieties or species of plants on a suitable nutrient medium to produce the somatic hybrids is called somatic hybridization. For example pomato is the somatic hybrid obtained by the protoplast fusion of tomato and potato.
The steps involved in somatic hybridization are :
(i) Single cells isolated from the selected plants.
(ii) Removal of cell wall of the fusing cell with the help of the enzymes like pectinase and cellulase. These enzymes digest the cell wall to expose the naked protoplast.
(iii) The isolated protoplasts of selected parents are fused to obtain hybrid protoplast on special nutrient medium under aseptic conditions.
This fusion is induced in the presence of polyethylene glycol (PEG) or by a brief high voltage electric current.
(iv) The hybrid protoplast are cultured on suitable nutrient medium, where they regenerate cell wall and begin to undergo division to form new plantlets. These plantlets are the somatic hybrids.
Use of somatic hybridization :
(a) Species of plants in which sexual hybridization or breeding is not possible can be hybridized by somatic hybridization.
(b) Somatic hybridization produces hybrids between those lines or species where it is not possible through sexual hybridization.
(c) This technique is useful in raising allopolyploids.