Class 9 NCERT Solutions Biology Chapter 12 - Improvements In Food Resources
141
142
143
144
145
146
147
148
148 cont.
150
150 cont.
151
Improvements In Food Resources Exercise 141
Solution 1
Cereals provide us carbohydrates for energy requirement.
Pulses provide us with protein for body building.
Fruits and vegetables provide us with a range of vitamins and minerals in addition to small amounts of proteins, carbohydrates and fats for proper growth and development of the body and maintenance of health.
Concept insight: The different components of food are carbohydrates, proteins, fats, vitamins and minerals. Students should remember the uses of various components of food.
Improvements In Food Resources Exercise 142
Solution 1
Both biotic and abiotic factors affect the crop production. Biotic factors like diseases, insects and nematodes and abiotic factors like drought, salinity, water logging, heat, cold and frost damages the crops thereby, decreasing the crop yield.
Concept insight: Students should remember and list various biotic and abiotic factors.
Solution 2
The desirable agronomic characteristics for crop improvement are:
i. Tallness and profuse branching in case of fodder crops.
ii. Dwarfness in case of cereal crops, so that the crop consumes less nutrients.
Thus, developing varieties of desired agronomic characters helps in increasing the productivity.
Concept insight: Important from Exam point of view.
Improvements In Food Resources Exercise 143
Solution 1
The nutrients required in large quantities are called macronutrients. Plants require nutrients for their growth and development. There are sixteen elements that are essential for plants. Out of sixteen, thirteen are provided by the soil. Among these thirteen, six of the nutrients are required by plants in large quantities and hence called macro-nutrients. They are Nitrogen, Phosphorus, Potassium, Calcium, Magnesium and Sulphur.
Concept insight: Students get confused between macro and micro nutrients. Macro and micro does not mean that one is important and the other is not. Both the macro and micro nutrients are important. The difference between them is, one is required in large quantity and the other is required in less quantity.
Concept insight: Students get confused between macro and micro nutrients. Macro and micro does not mean that one is important and the other is not. Both the macro and micro nutrients are important. The difference between them is, one is required in large quantity and the other is required in less quantity.
Solution 2
There are sixteen essential elements that are required by the plants for their growth and development. Out of sixteen, air supplies two nutrients, i.e., carbon and oxygen, water supplies hydrogen and the rest thirteen nutrients are supplied by the soil.
Concept insight: It is a common conclusion that plants get all the nutrients from the soil. It is not correct. Plants also get nutrients from air and water.
Improvements In Food Resources Exercise 144
Solution 1
| Manure | Fertilizer |
| i. Manures are rich in organic matter and poor in nutrients. ii.Bulk of organic matter helps in increasing the soil fertility. iii.Organic matter increases the water holding capacity in sandy soil and also helps to avoid water logging in clayey soil. iv. Reduces soil erosion and provides food to the microorganims. |
i. Fertilizers are rich in nutrients and poor in organic matter. ii. Provides specific nutrients to the plants. iii. Excessive use of fertilizer destroys soil fertility because organic matter is not replenished and microorganisms are harmed. iv. Excess fertilizer gets washed away due to excessive irrigation and causes water pollution. |
Concept insight:
- Differences should always be written in tabular form.
- Differences should be written in terms of their significance.
- Write only those many numbers of differences as stated in the question.
- Give example wherever possible.
Improvements In Food Resources Exercise 145
Solution 1
Conditions given in (c) will give the most benefits because all these conditions will increase the yield.
Concept insight: Important from Exam point of view.
Improvements In Food Resources Exercise 146
Solution 1
Preventive measures and biological control methods are preferred for protecting crops because of the following reasons:
i. Preventive measures like proper seed bed preparation, timely sowing of crops, intercropping and crop rotation helps in weed control. It also maintains the nutrient content of the soil.
ii. Use of resistant varieties, summer ploughing also help in destroying weeds and pests.
iii. Use of biological control method will reduce the chances of environmental pollution.
Concept insight: Important from Exam point of view.
Solution 2
Both biotic and abiotic factors are responsible for losses of grains during storage.
Biotic factors include insects, rodents, fungi, mites and bacteria.
Abiotic factors include inappropriate moisture and temperature in the place of storage.
Concept insight: Students should remember and list various biotic and abiotic factors.
Improvements In Food Resources Exercise 147
Solution 1
The commonly used method for improving cattle breeds is cross breeding. In this method, local breeds are cross bred with exotic breeds to get animals with both the desired qualities. For example in case of cattle, a cross between exotic breed which has long lactation period and the local breed which shows excellent resistant to diseases, both the desired qualities are obtained.
Concept insight: Students should not get confused between cross breeding and hybridization. Any term can be used while the explanation remains the same.
Improvements In Food Resources Exercise 148
Solution 1
Poultry farming is undertaken primarily to raise domestic fowl for egg production as well as chicken meat. The feed consumed by poultry birds is fibrous, and cheap. Moreover, it is formulated using agricultural byproduct. In this way, the product not used by human population are converted into chicken meat and the eggs produced by poultry birds, which are highly nutritious used by human.
Concept insight: Suggested Exam type question.
Improvements In Food Resources Exercise 148 cont.
Solution 1
Management practices common in both dairy and poultry farming are:
i. Specific nutritional requirements.
ii. Maintenance of proper shelter.
iii. Protection from pests and diseases.
Concept insight: Steps required for the management of cattle and poultry should be remembered.
Solution 2
| Broilers | Layers |
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i.Broilers are maintained for getting meat. ii. They require conditions to grow fast and low mortality. iii. Their daily food requirement is rich in protein and vitamin A and K. The fat content also should be adequate.
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i.Layers are egg-laying birds managed for the purpose of getting eggs. ii. They require enough space and lighting. iii. They require restricted and calculated feed with vitamins, minerals and micronutrients.
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Concept insight:
- Differences should always be written in tabular form
- Differences should be written in terms of their significance.
- Write only those many numbers of differences as stated in the question.
- Give example wherever possible.
Improvements In Food Resources Exercise 150
Solution 1
There are two ways of obtaining fish. One from the natural resources, which is called capture fishing and another by fish farming, which is called culture fishery.
Concept insight: Suggested Exam type question.
Solution 2
In composite fish culture, a combination of five or six fish species are used in a single fish pond. The species are selected in such a way that they do not compete for food among themselves as they have different food habits. Due to this the food available in all the parts of the pond is used. This automatically increases the fish yield from the pond.
Concept insight: Important from Exam point of view.
Improvements In Food Resources Exercise 150 cont.
Solution 1
The desirable characters of bee varieties suitable for honey production are:
(i) High honey collection capacity.
(ii) Sting less.
(iii) Stay in the beehive for longer periods and breed well.
(ii) Sting less.
(iii) Stay in the beehive for longer periods and breed well.
Concept insight: Important from Exam point of view.
Solution 2
The term pasturage means the flowers available to the bees for collecting nectar and pollens. Honey production depends on:
i. Amount of pasturage available.
ii. Kind of flowers available will determine the taste of the honey.
Concept insight: Suggested Exam type question.
Improvements In Food Resources Exercise 151
Solution 1
Cropping pattern is one method of crop production which ensures high yield. There are different ways of growing crops. Mixed cropping, inter cropping and crop rotations are few of them.
i. Mixed cropping: Growing of two or more crops simultaneously on the same piece of land is called mixed cropping. For example, growing wheat and gram or mustard. This reduces the chance of crop failure.
ii. Intercropping: Growing two or more crops on the same field in a specific pattern is called intercropping. Few rows of one crop alternate with the few rows of the other crop. For example soyabean and maize. This pattern utilizes the maximum nutrients and controls weed and pest.
iii. Crop rotation: Growing of crops on a piece of land in a pre-planned succession is called crop rotation. It maintains the fertility of the soil and also controls pest and weed.
Concept insight: Students should remember various types of cropping patterns and differences between them.
Solution 2
Manures and fertilizers are used in the field to increase the crop yield.
Concept insight: Students should remember the uses of manures and fertilizers.
Solution 3
Advantages of Intercropping:
i. Two or more crops are grown simultaneously on the same field.
ii. Reduces the changes of intraspecific competition and ensures the maximum utilization of the nutrients supplied.
iii. Prevents the spread of diseases and pests from spreading to all the plants.
iv. It also maintains soil fertility.
Advantages of Crop rotation:
i. Two or more crops are grown in a year.
ii. Makes the soil fertile and helps to increase the production of crop yield.
iii. It also decreases the demand of nitrogenous fertilisers as leguminous plants grown during crop rotation fix the atmospheric nitrogen, thus the soil becomes enriched with nitrogen compounds.
iv. Rotation of crops also helps in pest control, as pests do not find their favourite crop in the next season and it becomes difficult for them to survive there.
Concept insight: Students generally get confused between different cropping patterns such as inter cropping, crop rotation and crop rotation. Solution 4
Changing or altering the genetic composition of a crop by introducing a gene to get desired characteristics is called genetic manipulation.
Genetic manipulation helps in obtaining varieties with various desirable characteristics such as:
i. High yield
ii. Improved quality
iii. Biotic and abiotic resistance
iv. Wider adaptability
v. Desirable agronomic traits
Concept insight: Students should not get confused between genetic manipulation and hybridization.
Solution 5
Storage losses occur due to:
i. Abiotic factors like moisture and temperature of the storage area.
ii. Biotic factors like insects, rodents, fungi, mites and bacteria.
Concept insight: Important from Exam point of view.
Solution 6
Animal husbandry means proper management of farm animals. It includes feeding, proper shelter, care and protection from pests and diseases.
Good animal husbandry practices benefit the farmers in the following ways:
i. Proper shelter and protection from pests and diseases increases the economic conditions of the animals.
ii. Increases the yield of animal produce such as meat, egg, milk, fur etc.
iii. Improved breeds of the animal are obtained.
Concept insight: Suggested Exam type question.
Solution 7
Benefits of cattle farming are:
i. Producing high milk yielding animals.
ii. Producing good breed of drought animals.
Concept insight: Suggested Exam type question.
Solution 8
For increasing production, common activities in poultry, fisheries and bee keeping are:
i. Cross breeding to get an improved variety.
ii. Taking care of the food requirement.
iii. Proper care and protection from diseases.
Concept insight: Steps required for the management of poultry, pisciculture and apiculture should be clearly remembered.
Solution 9
| Capture fishing | Mariculture | Aquaculture |
| i.It is the process of obtaining fish from the natural resources like ponds, canals, rivers, etc. ii.In capture fishing, fish can be located easily and then caught using fishing nets. |
i.It is a practice of culture of marine fish varieties in the open sea. ii.In mariculture, satellites and echo-sounders are used for locating fish. Then, they are caught using many kinds of fishing nets from fishing boats. |
i.It means the production of fish from both fresh water as well as marine water. ii.Like capture fishing, in aquaculture also the fish can be located easily and are caught using fishing nets. |
Concept insight:
- Differences should always be written in tabular form.
- Differences should be written in terms of their significance.
- Write only those many numbers of differences as stated in the question.
- Give example wherever possible.
