The VIDYANKER team has thoughtfully prepared the NCERT Solutions for Class 12 Biology Chapter 9, "Strategies for Enhancement in Food Production" These solutions are designed to help you tackle the NCERT textbook questions with ease. We recommend going through the chapter's theory before diving into the solutions for a deeper understanding. Feel free to share these NCERT Solutions for Class 12 Biology with others—learning is always better when shared!
QUESTIONS FROM TEXTBOOK SOLVED
1. Explain in brief the role of animal husbandry in human welfare.
Ans: Animal husbandry is the scientific management of livestock. It generally includes feeding, breeding, and control of diseases to increase the population of animal livestock. Animals like cattle, pig, sheep, poultry, and fish are usually included in animal husbandry, which are beneficial for mankind in different ways. These animals are managed for commercially important products that include milk, meat, wool, egg, honey, and silk, etc. The more the human population increases, the greater their demand for those commodities becomes. There is then a requirement to devise and improve the management of the livestock scientifically.
2. If your family owned a dairy farm, what measures would you undertake to improve the quality and quantity of milk production?
Ans: If my family owned a dairy farm, I would take the following measures to improve both the quality and quantity of milk production:
1. Genetic Improvement of Cattle:
Selective breeding: Implement selective breeding programs to enhance the genetic traits of dairy cattle, such as higher milk yield, disease resistance, and better feed conversion efficiency.
Artificial insemination: Use artificial insemination (AI) with semen from high-yielding bulls to produce cows with superior genetic traits.
Cross-breeding: Crossbreed local breeds with high-yielding exotic breeds (e.g., Jersey, Holstein-Friesian) to combine good milk production with adaptability to local conditions.
2. Balanced Nutrition:
Nutrient-rich feed: Provide a balanced diet rich in proteins, vitamins, and minerals, including high-quality forages (alfalfa, clover), grains, and silage.
Feed supplements: Incorporate supplements such as calcium, phosphorus, and vitamins (A, D, E) to improve cow health and milk yield.
Precision feeding: Monitor and adjust the feed according to the cow's lactation stage, weight, and health to maximize milk production efficiency.
3. Health Management:
Regular veterinary check-ups: Ensure regular health checks and vaccinations to prevent diseases like mastitis, foot and mouth disease, and reproductive disorders that can reduce milk production.
Proper hygiene: Maintain cleanliness in barns, milking areas, and milking equipment to prevent contamination and udder infections.
Early disease detection: Use technology like automated health monitoring systems to detect early signs of illness, ensuring timely intervention.
4. Proper Milking Techniques:
Automated milking systems: Use automatic milking machines to improve efficiency and reduce stress on the cows, while ensuring proper milking hygiene.
Milking schedule: Stick to a regular and stress-free milking schedule (2–3 times a day) to maximize milk yield.
Udder care: Ensure proper udder cleaning and disinfection before and after milking to prevent infections like mastitis.
5. Cow Comfort and Stress Management:
Comfortable housing: Provide well-ventilated, clean, and spacious barns to reduce heat stress and ensure the cows are comfortable.
Ample resting space: Offer soft bedding and enough space for cows to rest, as comfortable cows produce more milk.
Water availability: Ensure cows have constant access to clean and fresh water, as hydration is critical for milk production.
6. Reproductive Management:
Heat detection: Use heat detection aids (such as sensors or visual monitoring) to detect the optimal time for breeding, reducing the interval between calvings.
Efficient calving cycle: Manage the reproductive cycle to ensure cows are calving regularly, as this maintains consistent milk production.
7. Record Keeping and Data Analysis:
Track performance: Maintain detailed records of each cow’s milk yield, health status, feeding, and breeding history to identify areas for improvement.
Data-driven decisions: Use farm management software to analyze data and make informed decisions about feeding, breeding, and health management.
8. Sustainability and Environment:
Manure management: Implement proper waste management practices to use manure as fertilizer and reduce environmental pollution.
Energy efficiency: Explore renewable energy sources (e.g., solar, biogas) to power farm operations, reducing costs and improving sustainability.
9. Training and Education:
Staff training: Ensure farmworkers are well-trained in animal handling, milking procedures, feeding practices, and disease management.
Continuous learning: Stay updated on the latest dairy farming techniques, technologies, and research to continuously improve operations.
By focusing on genetic improvement, proper nutrition, health care, and efficient management practices, the dairy farm can achieve higher milk yield, improved milk quality, and overall better farm productivity.
3. What is meant by the term ‘breed’ ? What are the objectives of animal breeding?
Ans: A breed is an improved variation of animals under a species. It has similar main features with other members of the same species in most aspects such as general appearance, size, configuration, and features.
Example: Jersey and Brown Swiss are exotics dairy cattle breeds. These cattle breeds have the potential to deliver large quantities of milk that is rich with high protein.
The main objectives of animal breeding are:
(i) To improve the desirable qualities of the animal produce
(i) To increase the yield of animals
(iii) To produce disease-resistant varieties of animals.
4. Name the methods employed in animal breeding. According to you which of the methods is best? Why?
Ans: Animal breeding is defined as the method of mating pets of specific relationships to obtain offspring that would possess specific characteristics which would have been bred for over time. Although the process of breeding has existed for centuries, modern advances in genetics have provided several techniques that may be used in animal breeding, which are listed below:
(i) Breeding methods based on natural breeding include inbreeding and out-crossbreeding. Inbreeding definition, is breeding within the same breed of animals, while out-breeding is mating between animals of different breeds. Full out-breeding of animals is classified into three types:
→ Out-crossing: This is a type of out-breeding where the mating of animals is conducted within the same breed but on different sets of family trees with no common family member for the last 4-5 generations.
→ Cross-breeding: At this subtype of out-breeding, mating takes place between individuals of two different genetic make up but of the same general species resulting in hybrids.
→ Interspecific hybridization: This is a subtype of out-breeding where mating takes place between individuals of two different species.
(ii) Methods of breeding artificially include modern advancements in breeding. It involves controlled experiments in breeding factors which are of two types:-
→ Artificial insemination, which means placing one or few million spermatozoa (collected from a male) into the oviduct or directly into the womb of a female for breeding by the breeder. This breeding method helps in eradicating certain challenges associated with abnormal mating of the sexes.
→ Multiple ovulation embryo technology (MOET), a new technology for cattle improvement. A hormone is given to the cow in order to induce super-ovulation, After that the cow is artificially inseminated and embryos are collected from the positive cows at an early stage. Each of these embryos is then implanted into the surrogate mother for completion of embryo development.
Of these two namely artificial and conventional method of animal husbandry the artificial method is the one which has been found to be the one improving basing the principles on artificial insemination and MOET technology. The application of these technologies is not non-intellectual. It addresses normal mating problems and ensures the crossing of mature males and female require very few attempts and has a high level of success. Furthermore, it also ensures the hybrid animals with desired attributes are produced. This is a Very cost effective way since only little semen from the male is required to reach many numbers of cattle as insemination does not waste the semen.
5. What is apiculture? How is it important in our lives?
Ans: Bee farming involves keeping and breeding bees in order to harvest honey. It is relevant in our everyday lives as honey bees are regarded as producers of honey, which is a very rich food supplement, while bees wax is applied in multiple sectors of the economy. The honey bee assists in fertilizing the blossoms of several economically significant crops, including the sunflower, apples, and pears.
6. Discuss the role of fishery in enhancement of food production.
Ans: A Fishery is defined as the industry of catching, processing, and selling all kinds of fish and even aquatic animals that are considered to have economic value. Some of these commercially exploited aquatic animals include shrimps, lobsters, crab, oysters, and the common octopus. Fisheries are of great importance in relation to the economy of India. A large segment of the Indian population relies on fish for food because it is relatively inexpensive, and contains a high quantity of animal protein fishes. Prawn culture being a fishery based industry provides employment opportunities mostly in coastal areas. High economic value is placed on both fresh water fishes (Catla, Rohu, etc) and marine fishes (such as tuna, mackerel pomfret etc.)
7. Briefly describe various steps involved in plant breeding.
Ans: Plant breeding is crossing two genetically dissimilar varieties in a controlled manner to form a new hybrid variety. Thus, some characters of the hybrid plant probably come from each parent. It entails general creation of a new variety incorporating numerous desired characters, such as disease resistance, climatic adaptability, and increased productivity. The various steps that are followed in plant breeding are:
- Collection of genetic variability: Genetic variability from various wild relatives of the cultivated species is collected to maintain the genetic diversity of a species; the entire collection of the diverse alleles of a gene in a crop is called the germplasm collection.
- Evaluation of germplasm and selection of parents: Then the referred germplasm was evaluated in terms of preferable genes. The selected plants with desired genes are then used as parents in plant breeding experiments and are multiplied by this process of hybridization.
- Crosshybridization between selected parents: The next important step involved is combining the desirable characters present in two different parents, leading to hybridizine. This work is tedious because the pollen grains collected from the male parent should make it to the stigma of the female parent.
- Selection of superior hybrids: The progenies of the hybrids with the desired traits are selected through scientific evaluation. The selected progenies were then self-pollinated for several generations to ensure homozygosity.
- Testing, release, and commercialization of new cultivars: The selected progenies are evaluated for characters like yield, resistance to diseases, performance, etc., by growing them in research fields for at least three growing seasons in different parts of the country. After thorough testing and evaluation, selected varieties are given to the farmers for field cultivation to establish large-scale production.
8. Explain what is meant by biofortification.
Ans: Biofortification is the biological augmentation of the nutritional content in crops through natural means such as traditional breeding and genetic engineering or agronomic practices. Biofortification increases the nutrient content, like vitamins, minerals, and proteins, in edible parts of crops, which would benefit people consuming these crops nutritionally.
Key Aspects of Biofortification:
Increased Nutrient Content:
Crops are bred or engineered to contain higher levels of micronutrients like iron, zinc, vitamin A (beta-carotene), and folate, which are often deficient in many diets.
Sustainable Solution to Malnutrition:
Biofortification provides a cost-effective and long-term approach to address nutrient deficiencies, especially in regions where people rely on staple crops like rice, wheat, and maize for most of their diet.
Methods of Biofortification:
Conventional breeding: Crossbreeding plants with naturally high nutrient levels to develop new varieties.
Genetic engineering: Modifying the genetic makeup of plants to boost nutrient levels (e.g., Golden Rice, which is rich in vitamin A).
Agronomic practices: Applying nutrient-rich fertilizers or other methods to increase the nutrient uptake by crops.
Examples of Biofortified Crops:
Golden Rice: Genetically modified rice enriched with beta-carotene to combat vitamin A deficiency.
Iron-rich pearl millet: Developed to improve iron intake in regions with high rates of anemia.
Zinc-enriched wheat: Created to address zinc deficiency, which affects immune function and growth.
Importance of Biofortification:
Biofortified crops include crops cured to contribute positively to the public health of different population groups suffering from "hidden hunger," where caloric intake is decent, but there is a deficiency of important nutrients. This constitutes an approach to combating malnutrition without dietary supplements.
9. Which part of the plant is best suited for making virus-free plants and why?
Ans: Meristematic cells of apical and axillary buds are the best portion of the plants, from which one can obtain virus-free plants. It is because the rate of division of a meristematic cell is higher than that of multiplication of a virus, and viruses are not able to enter newly formed meristematic cells. So, though the whole plant is infected with the virus, the cells of the meristem are free from the virus. Meristem thus enables the microbial culture to obtain healthy plants from a diseased one by using the micropropagation method.
10. What is the major advantage of producing plants by micro propagation?
Ans: It is faster method of producing a large number of plants. Plants formed by micro propagation are identical.
11. Find out the various components of the medium 12.used for propagation of an explant in vitro are ?
Ans: In in vitro plant tissue culture, the medium used for the propagation of an explant is crucial for its growth and development. The typical components of the culture medium include:
Mineral salts: Provide essential macronutrients (like nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur) and micronutrients (like iron, manganese, zinc, boron, copper, and molybdenum) necessary for plant growth.
Carbon source: Sucrose is commonly used as a carbohydrate source to provide energy for cell division and growth.
Vitamins: Thiamine (Vitamin B1), Pyridoxine (Vitamin B6), and Nicotinic acid (Niacin) are frequently used to promote cellular metabolism and enzyme activity.
Growth regulators: Auxins (like Indole-3-acetic acid, Naphthalene acetic acid) and Cytokinins (like BAP, Kinetin) are added to regulate cell division, differentiation, and organ formation.
The balance between auxins and cytokinins controls root and shoot formation.
Amino acids: Compounds like L-glutamine, Glycine, or Casein hydrolysate are used to enhance growth, as they serve as organic nitrogen sources.
Agar or Gelrite: Used as a gelling agent to solidify the medium, providing support for the explant. Sometimes, a liquid medium without agar is also used for specific purposes (e.g., suspension cultures).
Organic supplements: Compounds like coconut milk, yeast extract, or banana pulp may be added to enhance growth, as they contain hormones, vitamins, and other nutrients.
pH: The pH of the medium is generally adjusted to 5.6–5.8 to provide an optimal environment for plant tissue culture.
A well-known example of such a medium is Murashige and Skoog (MS) medium, which contains all these components in specific concentrations.
12. Name any five hybrid varieties of crop plants which have been developed in India.
Ans: Here are five hybrid varieties of crop plants developed in India:
- IR-8 (Rice): This high-yielding hybrid variety of rice was developed through the International Rice Research Institute (IRRI) and played a key role in the Green Revolution in India.
- Sonalika (Wheat): A high-yielding wheat variety that helped boost wheat production during the Green Revolution.
- Pusa Shubra (Cauliflower): A hybrid cauliflower variety developed by the Indian Agricultural Research Institute (IARI), known for its improved yield and quality.
- Arka Anamika (Okra): A hybrid variety of okra developed by the Indian Institute of Horticultural Research (IIHR), known for its resistance to pests and diseases.
- Pusa Swarnim (Mustard): A high-yielding mustard variety developed by IARI, known for its resistance to white rust disease.
These hybrid varieties have significantly contributed to the enhancement of food production in India.
