Food Production | ICSE Class 8 Biology Notes

This note covers food sources, useful bacteria and fungi, food crops and cash crops, crop production, horticulture, organic farming, the Green and White Revolutions, animal husbandry, poultry, fish farming, beekeeping and silk production.

What are the main sources of food and useful farm products?

Food production involves producing food from plants, animals and the activities of useful microorganisms. A microorganism, or microbe, is an organism too small to be seen with the unaided eye. Food supplies energy for the activities of living organisms.

Agriculture includes cultivating land to grow crops. A crop consists of plants of the same kind grown at one place on a large scale. A wheat field is an example: the cultivated plants are wheat plants.

How do food crops and cash crops differ?

Food crops are grown for food, whereas cash crops are grown for sale and income. Jute is an example of a cash crop grown in India. These descriptions concern purpose. A food crop can also be sold, so earning money from a crop does not mean that its product is inedible.

Cereals are grain crops such as rice, wheat and maize. Pulses are the edible seeds of leguminous plants, such as gram and peas. Leguminous plants belong to the bean and pea group. Fruits, vegetables and oil-yielding crops also contribute to our food supply.

Plants provide products other than food, including fibre, timber, medicines and oils. Animals provide milk, meat, eggs, honey and silk. These different products explain why farming includes activities beyond growing grain.

A useful distinction is between the organism and the product. A cow is a food-producing animal, while milk is its product. Similarly, wheat is a crop plant, while the harvested grain is its useful product.

How do bacteria help in making curd and cheese?

Bacteria are single-celled microorganisms. Some cause disease, but others are useful in food production. Lactobacillus is a type of bacterium involved in converting milk into curd. Curd contains several kinds of bacteria, not just one kind.

Fermentation, in these food-making processes, is the breakdown of sugars by microorganisms into products such as acids or alcohol. Lactose is the sugar in milk. Lactobacillus feeds on this sugar, multiplies and produces lactic acid, which makes curd sour.

What happens when a little curd is added to milk?

The added curd acts as a starter, meaning material that introduces useful microorganisms into fresh milk. At suitable temperatures, the bacteria multiply. Proteins are nutrients needed for growth and repair. The bacterial acids make milk proteins coagulate, or come together into a thicker mass, and partially digest those proteins.

1. Take lukewarm milk in a bowl.
2. Add a small spoonful of curd and mix it into the milk.
3. Cover the bowl and keep it in a warm place for a few hours or overnight.
4. Observe the formation of curd as the bacteria act on milk sugar. The curd becomes a little sour.

For comparison, cold milk with added curd can be kept in a cool place. Under these conditions, it does not curdle during the comparison, but it might be a little sour. The warm conditions favour the growth of the curd-forming bacteria.

Why are different cheeses different?

Microorganisms also help make cheese. The microbes used contribute to characteristic texture, flavour and taste. The large holes in Swiss cheese result from carbon dioxide, a gas produced by bacteria during its preparation.

Some cheeses involve fungi, organisms that include moulds and mushrooms. Roquefort cheese is ripened by growing a specific fungus on it, which gives it a particular flavour. Thus, cheese-making is not an example of bacteria acting alone in every variety of cheese.

Note: Useful bacteria change milk into curd under suitable conditions. This does not mean that every microorganism growing in a food makes that food useful or suitable to eat.

How do yeast and mushrooms contribute to food production?

Fungi are organisms that include yeasts, moulds and mushrooms. Their cells lack the structures needed to make food using sunlight. A yeast is a single-celled fungus. An edible mushroom is a larger fungus used directly as food.

Why does yeast make dough rise?

Dough is the soft mixture made by kneading flour with water. Yeast grows well in warm conditions and breaks down food to release energy. During this process, it releases carbon dioxide, whose bubbles make the dough soft and fluffy.

Yeast also produces a small amount of alcohol during this process. This gives the dough a slightly different smell. The production of gas, rather than simply the presence of yeast powder, explains the change in the dough.

1. Label two bowls A and B. Put 200 grams of flour and a pinch of sugar in each bowl.
2. Add a small amount of yeast powder to bowl A and mix it in. Do not add yeast to bowl B.
3. Knead both mixtures with warm water to make soft dough.
4. Cover the dough with a damp cloth and keep the bowls in a warm place.
5. Observe after 4 to 5 hours. If there is no change, leave the dough for some more time before comparing it again.

After some time, the dough in bowl A may have risen slightly, become fluffy and developed a different smell. Bowl B provides a comparison without added yeast. Keeping the other stated conditions alike helps relate the difference to the added yeast.

Figure: Change in the volume of flour after addition of yeast, sugar, and warm water (NCERT Class 8 Figure 2.11). The photographs show dough in two glass bowls. The dough labelled A occupies more of its bowl than the smaller lump labelled B. Yeast was added to bowl A but not to bowl B.

How are mushrooms different from yeast in food use?

Edible mushrooms are themselves eaten. Yeast is used to change ingredients during food preparation, including bread-making. Both are fungi, but their roles differ: one supplies an edible product directly, while the other helps produce a food through its activity.

What steps are involved in producing and storing a crop?

Crop production requires a sequence of agricultural practices, meaning the tasks used to grow and manage crops. These include preparing soil, sowing, supplying nutrients and water, controlling weeds, harvesting and storing the produce. Each task supports a different part of production.

How is a crop established and cared for?

1. Prepare the soil. Tilling, or ploughing, loosens and turns the soil. Break large clumps and level the field to help sowing and watering.
2. Sow healthy seeds. Sowing means placing seeds in soil for growth. Suitable spacing helps plants obtain enough sunlight, water and nutrients without overcrowding.
3. Replenish nutrients. Add manure or fertilisers, materials that supply nutrients for growth. Repeated cultivation can leave the soil poor in nutrients.
4. Provide water. Irrigation is supplying water to crops at regular intervals. Its timing and frequency vary with the crop, soil and season.
5. Remove weeds. Weeds are unwanted plants growing with a crop. They compete for water, nutrients, space and light.
6. Harvest the mature crop. Harvesting means cutting or removing the crop after it has matured. It may be done by hand or with machinery.
7. Prepare grain for storage. Separate grain from the harvested material and dry it properly before protecting it in suitable storage.

Loose soil allows roots to grow deeper and breathe more easily. It also supports earthworms and soil microbes. A seed drill, a sowing implement, places seeds at equal distance and depth and covers them with soil, helping protect them from birds.

Why do harvesting and storage need separate attention?

Threshing separates grain from the harvested stalks and other material. Winnowing separates grain from lighter chaff, the unwanted husks and similar plant material. These operations prepare grain for use or storage after the crop has been cut.

Freshly harvested grains contain moisture. If stored without drying, they may get spoilt or attacked by organisms. Sun-drying reduces their moisture before storage. Protection is also needed against insects, rats and microorganisms.

Grain can be stored in jute bags or metal bins. Large quantities are stored in silos and granaries, structures used for grain storage. Good production therefore includes care after harvest, because a crop that grows well can still suffer losses during storage.

What is horticulture, and how are its plants supplied with water?

Horticulture is the cultivation of fruits, vegetables, flowers and ornamental plants. Ornamental plants are grown for decoration. The group therefore includes plants used as food as well as plants valued for their appearance.

Mango and banana are examples of fruit crops. Cauliflower, onion, cabbage, tomato, brinjal and potato are examples of vegetable crops. Rose is an example of a decorative flowering plant. The purpose of cultivation helps explain the range covered by horticulture.

Why are water and plant spacing important?

Plants need water for growth. Their roots absorb water, and dissolved nutrients are transported through the plant. Seeds do not germinate under dry conditions. Germination means the beginning of a seed’s growth into a new plant.

Planting at suitable distances prevents overcrowding and helps plants obtain sunlight, nutrients and water. Some plants are first grown in a nursery, a place where young plants are raised before being moved elsewhere. Some flowering plants are grown this way.

How do sprinkler and drip irrigation differ?

In a sprinkler system, water moves through pipes under pressure and escapes through rotating nozzles. It falls over the crop like rain. This system is more useful on uneven land where sufficient water is not available.

In a drip system, water falls drop by drop directly near the roots. It is used for fruit plants, gardens and trees. The location of water delivery distinguishes drip irrigation from the rain-like distribution of a sprinkler.

Two drawings show a pump beside a well connected to pipes across planted ground. In the upper drawing, upright outlets spray water. In the lower drawing, pipes run beside rows of plants to deliver water near them.

See Fig. 1.5 in your NCERT textbook

How do organic farming and soil microorganisms support crops?

Organic farming is a farming system that seeks to maintain and improve ecological balance by using organic inputs and biological methods instead of chemical fertilisers and pesticides. Ecological balance concerns the relationships among organisms and their surroundings.

Manure is material obtained from the decomposition of plant or animal waste. Decomposition means the breakdown of this waste into simpler substances. Some bacteria and fungi carry out this process and return nutrients to the soil.

How are manure and fertilisers different?

Fertilisers are manufactured materials rich in particular plant nutrients, such as nitrogen, phosphorus or potassium. These are chemical elements required by plants. Humus is decomposed organic matter in soil. Manure supplies humus as well as nutrients.

Manure also makes the soil more porous, allowing gases to move through it, and increases friendly microbes. Organic farming is broader than adding manure once: it concerns the way the farming system is managed.

How do legumes help replenish soil nitrogen?

Rhizobium is a bacterium found in root nodules, swollen regions on the roots of certain legumes, such as beans, peas and lentils. The bacteria trap nitrogen from the air and make it usable by plants.

Crop rotation means growing different crops alternately on the same land. Growing legumes in rotation with other crops naturally increases soil nitrogen and helps keep the soil healthy for the next crop.

The illustration shows a leafy cowpea plant above a branching root system. Small swellings occur along the roots. These root nodules contain Rhizobium bacteria.

See Fig. 2.12 in your NCERT textbook

Organic farming also has limitations. Yields are lower than those of modern agricultural farming in the initial years. Organic produce may also have more blemishes and a shorter shelf life than sprayed produce. Shelf life is the period for which produce can be kept suitable for use.

What were the Green Revolution and the White Revolution?

The Green Revolution refers to the large increase in foodgrain production associated with high-yielding varieties, especially wheat and rice. A high-yielding variety is a crop variety developed for high production. Yield means the amount of crop produced from a given area.

Why were improved seeds only part of the change?

The seeds required fertilisers and pesticides in the correct quantities, together with a regular supply of water. Pesticides are substances used to control pests, organisms that damage crops. Reliable irrigation and access to the necessary farming materials were therefore important.

The combination of improved seeds and suitable management increased foodgrain production. It would be misleading to describe the change simply as planting different seeds without also considering water, nutrients and protection of the crop.

What changed in milk production?

The White Revolution refers to the increase in milk production. It concerns dairy development, whereas the Green Revolution concerns foodgrains. Dairying is the activity of producing and handling milk from milk-yielding animals.

Operation Flood helped develop a system in which farmers pooled their milk, graded it by quality, and had it processed and marketed through cooperatives. A cooperative is an organisation whose members work together for their shared benefit.

Milk cooperatives connect producers with urban markets and help ensure a fair price and income from milk supplies. The two revolutions therefore concern different products, even though both are linked to increasing the availability of food.

How do animal husbandry and poultry farming provide useful products?

Animal husbandry involves rearing animals on a large scale with proper food, shelter and care. Rearing means raising and looking after animals. Livestock means farm animals kept for useful products or work. Cattle, goats and poultry form part of farming systems alongside crops.

How do milch and draught animals differ?

Milch animals are milk-yielding animals. Cows, buffaloes, she-goats and she-camels provide milk. The term identifies the useful product. Milk can be consumed or used to make products such as curd and cheese.

Draught animals are animals used for heavy work, including agricultural work and transport. Bulls can pull a plough. Horses and camels can also be used to draw ploughs. These animals help production by supplying labour.

What is poultry farming?

Poultry farming is the raising of domestic birds for products such as eggs and meat. Chickens are an example. Broilers are chickens raised for meat. The product required helps determine the purpose for which the birds are reared.

Poultry birds, like other farm animals, need proper food, shelter and care. They can be affected by disease-causing bacteria, viruses and fungi. Veterinary care, meaning healthcare for animals, is important in improving livestock production.

Animal husbandry supports food supply and rural income. Crop cultivation and livestock rearing can occur together in a mixed crop-livestock system. Farm animals can supply food or provide services such as transport without replacing all the farm’s crop-growing activities.

Remember the different categories by their purpose: milk from milch animals, work from draught animals, and eggs or meat from poultry. A category describes a use; it is not the name of a separate biological group.

What is fish farming, and how does it differ from catching fish?

Pisciculture means fish farming: rearing fish for production. Culture fishery is fish production through farming, whereas capture fishery obtains fish by catching them from natural water resources. The distinction concerns how the fish supply is obtained.

Which water resources support fisheries?

Fisheries are activities concerned with obtaining fish and related aquatic produce. Aquatic means living in water. Seas and oceans provide marine resources. Marine means associated with the sea; inland resources include rivers, lakes, ponds and streams.

Fish provides food, and fisheries also provide livelihoods. A livelihood is a means of earning a living. The activity involves more than the moment of catching fish, because fish must also reach the people who use it.

Fish farming and capture fishing should not be treated as identical. Rearing fish is the central idea in pisciculture. Naming a river or sea alone does not establish that fish are being farmed there.

Problems such as overfishing and water pollution need control. Overfishing means excessive removal of fish from a resource. Increasing production must be considered together with the condition of water resources and the people whose livelihoods depend on them.

How do apiculture and sericulture differ?

Apiculture means beekeeping, the rearing of honeybees for useful products such as honey. Sericulture means rearing silkworms to produce silk fibre. Both involve useful animals, but their main products and the animals concerned are different.

What is obtained from honeybees?

Honey is an animal product used as food. Beekeeping is an activity that can provide rural income alongside other agricultural activities. It belongs with useful animal-rearing activities, rather than with the cultivation of cereal or vegetable crops.

Do not confuse the animal with the farming activity. Honeybee names the organism, honey names a product, and apiculture names the practice of keeping the bees. These three labels answer different questions about production.

Where does silk fibre come from?

Silk fibre is obtained from the cocoons of silkworms. A cocoon is a protective covering formed from silk around the developing insect. The silkworms are fed on green leaves, especially mulberry leaves.

Mulberry is a plant whose leaves are used as silkworm food. It supports silk production, but the silk itself comes from the silkworm’s cocoon. This differs from cotton and jute, whose fibres are obtained from plants.

Silk is a fibre product rather than a food product. Sericulture is studied alongside food-producing activities because agriculture and animal rearing supply other useful materials as well as food. Keeping the product in mind prevents confusion among these related activities.

Note: Match each practice to its product: pisciculture with fish, apiculture with honey, and sericulture with silk. Similar endings in their names do not mean that they involve the same organisms.

Glossary

• Crop — Plants of the same kind cultivated at one place on a large scale.
• Fermentation — Breakdown of sugars by microorganisms to produce substances such as acids or alcohol.
• Starter — Material added to introduce useful microorganisms, such as curd mixed into fresh milk.
• Yeast — A single-celled fungus used in bread-making, where its activity releases carbon dioxide.
• Horticulture — Cultivation of fruits, vegetables, flowers and ornamental plants for food or other uses.
• Manure — Material formed by decomposition of plant and animal wastes, supplying organic matter and nutrients.
• Crop rotation — Growing different crops alternately on the same land to help replenish soil nutrients.
• Irrigation — Supplying water to crops at regular intervals according to their growing requirements.
• Animal husbandry — Large-scale rearing of animals with proper food, shelter and care for useful products or work.
• Milch animals — Milk-yielding animals, including cows, buffaloes, she-goats and she-camels used for milk production.
• Draught animals — Animals used to perform heavy work such as pulling ploughs or providing transport.
• Pisciculture — Fish farming, involving rearing fish for production rather than simply capturing wild fish.
• Apiculture — Beekeeping, involving the rearing of honeybees for useful products such as honey.
• Sericulture — Rearing silkworms to obtain silk fibre from the cocoons that they produce.
• White Revolution — Increase in milk production associated with development of the dairy sector.

Common errors and misconceptions

• Misconception: Every microbe is harmful. Correct: Some microbes help make foods. Lactobacillus helps form curd, while yeast helps make bread dough soft and fluffy.
• Misconception: Yeast is a bacterium. Correct: Yeast is a single-celled fungus. Lactobacillus, which helps form curd, is a bacterium.
• Misconception: Dough rises because yeast adds a large solid mass. Correct: Carbon dioxide released by yeast forms bubbles that make the dough soft and fluffy.
• Misconception: Manure and fertilisers have identical effects. Correct: Manure adds humus and improves soil texture. Fertilisers supply concentrated nutrients without adding humus.
• Misconception: The Green Revolution concerns milk. Correct: The Green Revolution concerns increased foodgrain production; the White Revolution concerns increased milk production.
• Misconception: All fish production is pisciculture. Correct: Pisciculture means farming fish. Capture fishery obtains fish by catching them from natural resources.
• Misconception: Silk is obtained directly from mulberry leaves. Correct: Silkworms eat the leaves, but silk fibre is obtained from their cocoons.

Exam-style questions with model answers

Q1. Define a crop and give one example of a cereal crop. [2 marks]

1. A crop consists of plants of the same kind cultivated at one place on a large scale.
2. Wheat is an example of a cereal crop grown for its grain.

Q2. A spoonful of curd is mixed into lukewarm milk and kept covered in a warm place. Explain how bacteria turn the milk into sour curd, giving three points. [3 marks]

1. The spoonful of curd acts as a starter. It introduces bacteria, including Lactobacillus, into the fresh milk.
2. The bacteria grow well in warm conditions, multiply and act on lactose, the sugar present in milk.
3. They produce lactic acid, which makes the curd sour. Acids also cause milk proteins to coagulate and partially digest them.

Q3. Bowls A and B each contain 200 grams of flour and a pinch of sugar, kneaded with warm water. Yeast is added only to A. Both are covered with a damp cloth and kept warm. After 4 to 5 hours, A has risen slightly and smells different; B has not shown these changes. Explain the observations and the purpose of B in four points. [4 marks]

1. Bowl A contains yeast, a single-celled fungus that grows well in warm conditions and breaks down food to release energy.
2. Yeast releases carbon dioxide. Gas bubbles make the dough soft and fluffy and explain the observed slight rise.
3. Yeast also produces a small amount of alcohol during this process, accounting for the slightly different smell of the dough.
4. Bowl B provides a comparison without added yeast. The other stated ingredients and conditions are alike, helping connect the difference to yeast activity.

Q4. Compare manure and manufactured fertilisers under five headings: origin, place of preparation, humus, nutrient concentration and effects on soil or water. [5 marks]

1. Origin: Manure forms when plant and animal wastes decompose. Fertilisers are manufactured chemical materials used to provide particular plant nutrients.
2. Preparation: Manure can be prepared in the fields by allowing organic waste to decompose. Manufactured fertilisers are prepared in factories.
3. Humus: Manure supplies a lot of humus, or decomposed organic matter, to soil. Fertilisers do not supply this humus.
4. Nutrients: Manure is relatively less rich in plant nutrients. Fertilisers are very rich in particular nutrients such as nitrogen, phosphorus and potassium.
5. Effects: Manure improves soil texture and water-holding capacity. Excessive fertiliser use has made soil less fertile. Fertilisers have also become a source of water pollution.

Q5. Distinguish the Green Revolution from the White Revolution by stating the main product involved and one supporting method or organisation for each. Give four points. [4 marks]

1. The Green Revolution involved a large increase in foodgrain production, especially wheat and rice, associated with improved crop varieties.
2. It used high-yielding seeds with fertilisers and pesticides in correct quantities, together with a regular water supply through reliable irrigation.
3. The White Revolution refers to increased milk production and is associated with development of the dairy sector.
4. Operation Flood supported pooling, grading, processing and marketing milk through cooperatives, connecting milk producers with urban markets.

Q6. A farm grows wheat and tomato, keeps cows for milk and bulls for ploughing, rears chickens for eggs, and keeps honeybees for honey. Identify these six activities or useful categories, giving one point for each. [6 marks]

1. Growing wheat is cereal crop cultivation. Wheat plants grown together on a large scale form a crop that supplies grain for food.
2. Growing tomato is horticulture. Tomato is a vegetable crop, and horticulture includes growing vegetables as well as fruits and ornamental plants.
3. The cows kept for milk are milch animals. Their role in this farm is to supply milk as a food product.
4. The bulls used for ploughing are draught animals. They contribute agricultural labour by pulling the plough during preparation of the land.
5. Rearing chickens for eggs is poultry farming. Poultry provides eggs and meat, although the activity stated here is specifically egg production.
6. Keeping honeybees for honey is apiculture, or beekeeping. The named animal is the honeybee, and the useful product specified is honey.

Q7. Fish are reared for production in a pond. Silkworms are reared on green leaves, especially mulberry leaves, and their cocoons are collected for silk. Name the two rearing practices and identify the source of silk fibre in three points. [3 marks]

1. Rearing the fish for production is pisciculture, also called fish farming or culture fishery. The fish are being raised as a production activity.
2. Rearing silkworms for silk is sericulture. Mulberry leaves are used as food for the silkworms in the process described.
3. The silk fibre is obtained from the silkworms’ cocoons. It is an animal product, rather than a fibre obtained directly from the mulberry plant.

Key takeaways

• Food production depends on plants, animals and useful microorganisms, with different organisms supplying products or helping make them.
• Lactobacillus acts on milk sugar and produces lactic acid, helping convert milk into sour curd under suitable conditions.
• Yeast is a fungus whose carbon dioxide makes dough soft and fluffy; edible mushrooms are themselves used as food.
• Crop production includes soil preparation, sowing, nutrient supply, irrigation, weed control, harvesting and careful storage of produce.
• Horticulture includes fruits, vegetables and ornamental plants; it therefore provides both food products and plants grown for decoration.
• Manure improves soil properties, while crop rotation with legumes helps replenish nitrogen through bacteria living in root nodules.
• The Green Revolution concerns increased foodgrain production, while the White Revolution concerns increased milk production and dairy development.
• Pisciculture produces fish, apiculture supplies honey, and sericulture supplies silk fibre obtained from the cocoons of silkworms.

Test yourself

What does a small spoonful of curd contribute when added to fresh milk?

It acts as a starter, introducing bacteria that multiply under suitable conditions and help turn the milk into curd.

Which gas makes yeast-treated dough soft and fluffy?

Carbon dioxide released by yeast forms bubbles in the dough, making it soft and fluffy.

Why does a crop need protection from weeds?

Weeds compete with crop plants for water, nutrients, space and light, affecting the growth of the crop.

Why are freshly harvested grains dried before storage?

Drying reduces moisture. Grains stored without drying may get spoilt or attacked by organisms.

What are root nodules, and which useful bacterium can live in them?

Root nodules are swollen regions on the roots of certain legumes. They contain Rhizobium bacteria, which make atmospheric nitrogen usable by plants.

What distinguishes a milch animal from a draught animal?

A milch animal supplies milk, whereas a draught animal performs heavy work such as pulling a plough.

How does pisciculture differ from capture fishery?

Pisciculture involves farming fish, whereas capture fishery obtains fish by catching them from natural water resources.

Why should sericulture not be described as growing silk plants?

Sericulture involves rearing silkworms. Silk fibre comes from their cocoons, although green leaves, especially mulberry leaves, provide their food.