Students get through the TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology which is useful for their exam preparation.

TN State Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

Answer the following.

Question 1.
What is economic zoology?
Answer:
Economic Zoology is a branch of science that deals with economically useful animals. It involves the study of application of animals for human welfare.

Question 2.
Classify animals based on their economic importance.
Answer:
Based on the economic importance, animals can be categorized as:

  1. Animals for food and food products
  2. Economically beneficial animals.
  3. Animals of aesthetic importance
  4. Animals for scientific research.

Question 3.
Write the relationship between the soil and earthworm.
Answer:
Vermiculture is the process of using earthworms to decompose organic food waste, into a nutrient-rich material capable of supplying necessary nutrients which helps to sustain plant growth.

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

Question 4.
What is vermicompost?
Answer:
Vermicompost is the compost produced by the action of earthworms in association with all other organisms in the compost unit.

Question 5.
Why earthworms has got the names of “farmer’s friends’ and biological indicators of soil fertility?
Answer:
The disposal of solid wastes (bio-degradable and non-biodegradable) remains a serious challenge in most of the countries.
Earthworms play a vital role in maintaining soil fertility; hence these worms are called as “farmer’s friends”. These are also called as “biological indicators of soil fertility”. The reason is that they support bacteria, fungi, protozoans and a host of other organisms which are essential for sustaining a healthy soil.

Question 6.
What is vermicast?
Answer:
The breakdown of organic matter by the activity of the earthworms and its elimination from its body is called vermicast.

Question 7.
How are earthworms divided into groups?
Answer:
Earthworms are divided into two major groups. The first group, the humus formers, dwell on the surface and feed on organic matter. They are generally darker in colour. These worms are used for vermicomposting. The second group, the humus feeders, are burrowing worms that are useful in making the soil porous, and mixing and distributing humus throughout the soil.

Question 8.
Differentiate endemic and exotic species of earthworms with example.
Answer:
There are different endemic (native) species of earthworms cultured in India for vermicomposting such as Periyonyx excavatus, Lampito mauritii, Octochaetona serrata. Some earthworm species have been introduced from other countries and called as exotic species eg: Eisenia fetida, Eudrilus eugeniae.

Question 9.
How can we prepare vermicompost bed for culturing earthworms as well as preparing vermicompost and vermiwash?
Answer:

  1. Vermicompost bed may be selected on upland or an elevated level as it prevents the stagnation of water.
  2. A cement pit of 3 x 2 x 1m size(L x W x D) over ground surface using bricks. The size of pit may vary as per availability of raw materials. Cement pot or well rings are practically good. Provision should be made for excess water to drain. The vermibed should not be exposed to direct sunlight and hence shade may be provided. The first layer of vermibed contains gravel at about 5 cm in height, followed by coarse sand to a thickness of 3.5 cm, which will facilitate the drainage of excess water.
  3. Earthworms collected from native soil prefer a layer of local soil in their compost beds. If local soil earthworms are used, add a layer of native loamy soil for about 15 cm on top of the gravel sand layer and introduce earthworms into it.
  4. The unit can now be loaded with digested biomass or animal dung such as cow dung that has lost its heat. The number of earthworms to be introduced in an unit depends on the size of the vermibed prepared. Earthworms such as Periyonyx. excavatus, Eisenia fetida or Eudrilus Eugenie are introduced on the top. Jute bags or cardboards or broad leaves are used to cover the unit. As worms require moisture, water management is most important for the survival of earthworms. Too little or too much of water is not good for the worms.
  5. Earthworms release their castings on the surface. One can start harvesting this from the surface on noticing the castings on the surface. It may take several days for the entire biomass to be composted depending on the amount of biomass. When all the compost is harvested, earthworms can be handpicked by creating small conical heaps of harvested compost and leaving in sunlight for a few hours. The earthworms then move down and settle at the bottom of the heap as a cluster. Earthworms from the lower layers of the compost can be recovered and the worms can be transferred to new composting units.
  6. Vermiwash is a liquid collected after the passage of water through a column of vermibed. It is useful as a foliar spray to enhance plant growth and yield.

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

Question 10.
What is vermiwash? From where can we: obtained it. What is the use of it?
Answer:
Vermiwash is a liquid collected after the passage of water through a column of vermibed. It is useful as a foliar spray to enhance plant growth and yield. It is obtained from the burrows or drilospheres formed by earthworms. Nutrients, plant growth promoter substances and some useful microorganisms are present in vermiwash.

Question 11.
What are tne enemies of earthworm?
Answer:
Earthworm enemies include ants, springtails, centipedes, slugs, mites, certain beetle larvae, birds, rats, snakes, mice, toads, and other insects or animals which feed on worms. The earthworm has a number of internal parasites including numerous protozoa, some nematodes, and the larvae of certain flies.

Question 12.
Define sericulture?
Answer:
Sericulture is an agro -based industry, the term which denotes commercial production of silk through silkworm rearing.

Question 13.
Write the three main components of sericulture.
Answer:
Sericulture is an agro-based industry comprising three main components:

  1. cultivation of food plants for the silkworms,
  2. rearing of silkworms, and
  3. reeling and spinning of silk.

Question 14.
Write down the various steps of development involved in the life cycle of Bombyx Mori.
Answer:
Life cycle of Bombyx mori: The adult of Bombyx mori is about 2.5 cm in length and pale creamy white in colour. Due to heavy body and feeble wings, flight is not possible i by the female moth. This moth is unisexual in nature and does not feed during its very short life period of 2-3 days. Just after emergence, male moth copulates with female for about 2-3 hours and if not separated, they may die after few hours of copulating with female. Just after copulation, female starts egg laying which is completed in 1 24 hours. A single female moth lays 400 to 500 eggs depending upon the climatic conditions. Two types of eggs are generally found namely diapause type and non-diapause type. The diapause type is laid by silkworms inhabiting the temperate regions, whereas silkworms belonging to subtropical regions like India lay non-diapause type of eggs. The eggs after ten days of incubation hatch into larva called as caterpillar. The newly hatched caterpillar is about 3 mm in length and is pale, yellowish-white in colour. The caterpillars are provided with well developed mandibulate type of mouth-parts adapted to feed easily on the mulberry leaves.
After 1st, 2nd, 3 rd and 4th moultings caterpillars get transformed into 2nd, 3rd, 4th and 5th instars respectively. It takes about 21 to 25 days after hatching. The fully grown caterpillar is 7.5 cm in length. It develops salivary glands, stops feeding and undergoes pupation. The caterpillars stop feeding and move towards the comer among the leaves and secretes a sticky fluid through their silk gland. The secreted fluid comes out through spinneret (a narrow pore situated on the hypopharynx) and takes the form of long fine thread of silk which hardens on exposure to air and is wrapped around the body of caterpillar in the forms of a covering called as cocoon. It is the white coloured bed of the pupa whose outer threads are irregular while the inner threads are regular. The length of continuous thread secreted by a caterpillar for the formation • of cocoon is about 1000-1200 metres which requires 3 days to complete. The pupal period lasts for 10 to 12 days and the pupae cut through the cocoon and emerge into adult moth.

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

Question 15.
Classify the races of Bombyx mori on the basis of its moulting.
Answer:
On the basis of the moults which they undergo during their larval life, B. mori is divided into three races – tri-moulters, tetra- moulters and penta-moulters.

Question 16.
Write few species of silk moth and the types of silk obtained from them.
Answer:

Species of silkmoth Types of silk
Bombyx mori Mulberry silk
Antheraea assamensis Muga silk
Antheraea mylitta Tassar silk
Attacus ricini Eri silk

Question 17.
What is Voltinism? Classify the races of Bombyx mori or mulberry worm according to this.
Answer:
The number of broods raised per year is called voltinism. Three kinds of races are recognized in mulberry silkworm – univoltine (one brood only), bivoltine (two broods only), and multivoltine (more than two broods).

Question 18.
Define Moriculture? What for this is done?
Answer:
Mulberry leaves are widely used as food for silkworm Bombyx mori and the cultivation of mulberry is called as Moriculture.

Question 19.
Name the improved varieties of mulberry plants used for planting.
Answer:
Presently improved mulberry varieties like Victory 1, S36, G2, and G4 which can withstand various agro-climatic and soil conditions are used for planting.

Question 20.
How can we prepare a rearing house for silkworms, and how can it be reared?
Answer:
A typical rearing house (6m x 4m x 3.5m) is constructed on an elevated place under shade to accommodate 100 dfls (disease-free layings). Space of lm should be provided surrounding the rearing house. Sufficient windows and ventilators should be provided for free circulation of air inside the rearing house. The windows and ventilators should be covered with a nylon nets to restrict the entry of uzi flies and other insects. Apart from the specified area of the rearing house; the following appliances such* as hygrometer, power sprayers, rearing stands, foam pads, wax-coated paraffin papers, nylon nets, baskets for keeping leaves, gunny bags, rotary or bamboo mountages and drier are needed for effective rearing of silkworms. The steps involved in the rearing process of silkworms are disinfection of rearing house, incubation of eggs, brushing, young larval rearing, and late age larval rearing. The selected healthy silk moths are allowed to mate for 4 hours. The female moth is then kept in a dark plastic bed, it lays about 400 eggs in 24 hours; the female is taken out, crushed, and examined for any disease, only certified disease-free eggs are reared for industrial purposes. The eggs are incubated in an incubator. The small larvae (caterpillars) hatch between 7-10 days. These larvae are kept in trays inside a rearing house at a temperature of about 20°C – 25°C. These are first fed on chopped mulberry leaves. After 4-5 days fresh leaves are provided. As the larvae grow, they are transferred to fresh leaves on clean trays, when fully grown they spin cocoons. Their maturity is achieved in about 45 days. At this stage, the salivary glands (silk glands) start secreting silk to spin cocoons.

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

Question 21.
What are various appliances used for rearing Silkworms?
Answer:
The following appliances such as hygrometers, power sprayers, rearing stands, foam pads, wax-coated paraffin papers, nylon nets, baskets for keeping leaves, gunny bags, rotary or bamboo mountages and drier are needed for effective rearing of silkworms.

Question 22.
What are the steps involved in the rearing process of silkworms?
Answer:
The steps involved in the rearing process of silkworms are disinfection of rearing house, incubation of eggs, brushing, young larval rearing, and late age larval rearing.

Question 23.
What is post cocoon processing? What are the steps involved?
Answer:
The method of obtaining silk thread from the cocoon is known as post cocoon processing. This includes stifling and reeling.

Question 24.
Define stifling and Reeling.
Answer:
The process of killing the cocoons is called stifling. The process of removing the threads from the killed cocoon is called reeling.

Question 25.
How the reeling process of silk thread is done?
Answer:
For reeling silk the cocoons are gathered about 8-10 days after spinning had begun. The cocoons are first treated by steam or dry heat to kill the insect inside. This is necessary to prevent the destruction of the continuous fiber by the emergence of the moth. The cocoons are then soaked in hot water (95° -97°C) for 10-15 minutes to soften the gum that binds the silk threads together. This process is called cooking. The “cooked” cocoons are kept in hot water and the loose ends of the thread are caught by hand. Threads from several cocoons are wound together on spinning wheels (Charakhas) to form the reels of raw silk. Only about one-half of the silk of each cocoon is reliable, the remainder is used as a silk waste and formed into spun silk. Raw silk thus obtained is processed through several treatments to bring about the luster on the thread.

Question 26.
Tabulate some diseases which affect silkworms. Write their causative organisms also.
Answer:

Diseases Causative agent
Pebrine Nosema bombycis, a protozoan
Flacherie Streptococcus and Staphylococcus
Grasserie Nuclear polyhedrosis vims called Baculovirus
Muscardine Beauveria bassiana

Question 27.
What is apiculture or beekeeping.
Answer:
Care and management of honey bees on a commercial scale for the production of honey is called Apiculture or Bee Keeping.

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

Question 28.
Write the names of well-recognized types of bees in the world.
Answer:
There are five well-recognized types of bees in the world. They are Apis dorsata (Rock bee), Apis florea (Little bee), Apis iridic (Indian bee), Apis mellifera (European bee) and Apis Adamson (African bee).

Question 29.
What is a nuptial flight?
Answer:
The Queen bee is a functional female bee present in each hive and feeds on Royal Jelly. The virgin queen bee mates only once in her life. During the breeding season in winter, a unique flight takes place by the queen bee followed by several drones. This flight is called “nuptial flight”.

Question 30.
Write an account on the worker bee?
Answer:
Among the honey bees, workers are sterile females and smallest but yet function as the mainspring of the complicated machinery in. the colony. A worker bee lives in a chamber – called ‘Worker Cell’ and it takes about 21 days to develop from the egg to adult and its lifespan is about six weeks. Each worker has to perform different types of work in her lifetime. During the first half of her life, she becomes a nurse bee attending to indoor duties such as secretion of royal jelly, prepares bee-bread to feed the larvae, feeds the queen, takes care of the queen and drones, secretes beeswax, builds combs, cleans and fans the beehive.
Then she becomes a soldier and guards the beehive. In the second half of her life lasting for three weeks, she searches and gathers the pollen, nectar, propolis, and water.

Question 31.
Why drones are called ‘king of the colony’?
Answer:
The drone is the functional male member of the colony which develops from an unfertilized egg. It lives in a chamber called a drone cell. Drones totally depend on workers for honey. The sole duty of the drone is to fertilize the virgin queen hence called “King of the colony”. During swarming (the process of leaving the colony by the queen with a large group of worker bees to form a new colony) the drones follow the queen, copulates, and dies after copulation.

Question 32.
Write the structure of a beehive.
Answer:
The house of the honey bee is termed a beehive or comb. The hive consists of hexagonal cells made up of wax secreted by the abdomen of worker bees arranged in opposite rows on a common base. These hives are found hanging vertically from the rocks, buildings,s or branches of trees. The young stages of honey bees accommodate the lower and central cells of the hive called the brood cells. In Apis dorsata, the brood cells are similar in size and shape but in other species, brood cells are of three types viz., queen cell for queens, worker cell for workers, and drone cells for drones. The cells are intended for the storage of honey and pollen in the upper portion of the comb whereas the lower portions are for brood rearing.

Question 33.
Write the primary equipment of the Langstroth beehive.
Answer:
The Langstroth beehive is made up of wood and consists of six parts.

  1. The stand is the basal part of the hive on which the hive is constructed. The stands are adjusted to make a slope for rainwater to drain.
  2. Bottom board is situated above the stand and forms the proper base for the hive. It has two gates, one gate functions as an entrance while the other acts as an exit.
  3. The brood chamber is the most important part of the hive. It is provided with 5 to 10 frames arranged one above the other through which the workers can easily pass. The frame is composed of a wax sheet which is held in a vertical position up by a couple of wires. Every sheet of wax is known as Comb Foundation. The comb foundation helps in obtaining a regular strong worker brood cell comb which can be used repeatedly.
  4. Super is also a chamber without cover and base. It is provided with many frames containing a comb foundation to provide additional space for the expansion of the hive.
  5. The inner cover is a wooden piece used for covering the super with many holes for proper ventilation.
  6. The top cover is meant for protecting the colonies from rains. It is covered with a sheet that is plain and sloping.

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

Question 34.
Write few lines about the following.

  1. Queen Excluder,
  2. Bee Gloves,
  3. Bee Veil,
  4. Smoker,
  5. Bee brush,
  6. Honey extractor.

Answer:

  1. Queen Excluder is utilized to prevent the entry of queen bees from the brood chamber into the super chamber.
  2. Bee gloves are used by beekeepers for protecting their hands while inspecting the hives.
  3. A bee veil is a device made of fine nettings to protect the bee-keeper from bee stings.
  4. The smoker is used to scaring the bees during hive maintenance and honey collection by releasing smoke.
  5. Bee brush is a large brush often employed to brush off bees from honeycombs particularly at the time of extraction.
  6. Honey Extractor is a stainless-steel device that spins the combs rapidly to extract honey.

Question 35.
Give the economic importance of the chief products of beekeeping.
Answer:
The chief products of the beekeeping industry are honey and bee wax.
Honey is the healthier substitute for sugar. The major constituents of honey are levulose, dextrose, maltose, other sugars, enzymes, pigments, ash, and water. It is an aromatic sweet material derived from the nectar of plants. It is a natural food, the smell and taste depend upon the pollen taken by the honey bee. It is used as an antiseptic, laxative, and as sedative. It is generally used in Ayurvedic and Unani systems of medicine. It is also used in the preparation of cakes, bread, and biscuits.
Bee wax is secreted by the abdomen of the worker bees at the age of two weeks. The wax is masticated and mixed with the secretions of the cephalic glands to convert it into a plastic resinous substance. The resinous chemical substance present in the wax is called propolis which is derived from pollen grains. The pure wax is white in color and the yellow color is due to the presence of carotenoid pigments. It is used for making candles, waterproofing materials polishes for floors, furniture, appliances, leather, and taps. It is also used for the production of comb foundation sheets in beekeeping and used in pharmaceutical industries.

Question 36.
Define Lac culture.
Answer:
The culture of lac insect using techniques for the procurement of lac on large scale is known as Lac culture.

Question 37.
What is ‘swarming’ in lac insects?
Answer:
The female develops very rapidly after fertilization and lays about 200 to 500 eggs. Eggs hatch into larvae after six weeks. The mass emergence of larvae from the egg in search of a host plant is called ‘swarming”.

Question 38.
Write an account of the life cycle of the ‘Lac’ insect with a simple sketch.
Answer:
TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology 1
The female lac insect is responsible for the large-scale production of lac, which is larger than the male lac insect.
After copulation, the male insect dies. The female develops very rapidly after fertilization and lays about 200 to 500 eggs. Eggs hatch into larvae after six weeks. The mass emergence of larvae from the egg in search of a host plant is called ‘swarming’.
After settling on the host, the larvae start feeding continuously and the secretion of lac also starts simultaneously. Gradually the larvae become fully covered by lac. Then the larvae moult in their respective cells (chamber). The shapes of the cells are different for male and female insects, males are elongated whereas and the female is oval. The process of introducing lac insect on the host plant is called inoculation. Before inoculation, pruning of the host plant is done. The twigs having brood lac, i.e., lac insect about 20 cm in length are attached to fresh host plants. The lac insect then repeats its life cycle.

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

Question 39.
What is Aquaponics?
Answer:
Aquaponics is a technique that is a combination of aquaculture (growing fish) and hydroponics (growing plants in non-soil media and nutrient-laden water).

Question 40.
What is the use of Aquaponics?
Answer:
Aquaponics may also prevent toxic water runoff. It also maintains ecosystem balance by recycling the waste and excretory products produced by the fish.

Question 41.
What are the primary methods of aquaponic gardening used nowadays?
Answer:
Deep water culture, media-based method, nutrient film technique, and aqua Vertica.

Question 42.
What is deep water culture?
Answer:
Deepwater culture is otherwise known as the raft-based method. In this method, a raft floats in water. Plants are kept in the holes of the raft and the roots float in water. This method is applicable for larger commercial-scale systems. By this method, fast-growing plants are cultivated.

Question 43.
What is the media-based method?
Answer:
The media-based method involves growing plants in inert planting media like clay pellets or shales. This method is applicable for the home and hobby scale systems. A larger number of fruiting plants, leafy green plants, herbs, and other varieties of plants can be cultivated.

Question 44.
What is the nutrient film technique?
Answer:
The Nutrient Film technique involves the passage of nutrient-rich water through a narrow trough or PVC pipe. Plants are kept in the holes of the pipe to allow the roots to be in free contact within the water stream.

Question 45.
What is Aqua Vertica?
Answer:
Aqua Vertica is otherwise known as vertical aquaponics. Plants are stacked on top of each other in tower systems. Water flows in through the top of the tower. This method is suitable for growing leafy greens, strawberries, and other crops that do not need supporting solid substratum to grow.

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

Question 46.
Give an account of the advantages of Aquaponic gardening?
Answer:
Water conservation: No need for water discharge and recharge as the water is maintained by the recycling process.
Soil: Bottom soil may be loaded with freshwater. Microbes in water can convert the waste materials into usable forms like ammonia into nitrates which are used by the plants. Thus the soil fertility is maintained.
Pesticides: In this system use of pesticides is avoided and hence it is eco-friendly.
Weeds: Since the plants are cultured in confined conditions, the growth of weeds is completely absent. The utilization of nutrients by plants is high in this method.
Artificial food for fishes: ln this system plant waste and decays are utilized by fishes as food. So, the need for the use of supplementary feed can be minimized.
Fertilizer usage: Artificial or chemical fertilizers are not required for this system since the plants in the aquaponics utilize the nutrients from the fish wastes dissolved in water.

Question 47.
What is aquaculture?
Answer:
Aquaculture is a branch of science that deals with the farming of aquatic organisms such as fish, molluscs, crustaceans, and aquatic plants.

Question 48.
Mention the classification of aquaculture?
Answer:
On the basis of source, aquaculture can be classified into three categories. They are:

  1. Freshwater aquaculture,
  2. Brackishwater aquaculture,
  3. Marine water aquaculture.

Question 49.
What is freshwater aquaculture?
Answer:
Inland water bodies include freshwater bodies like rivers, canals, streams, lakes, flood plain wetlands, reservoirs, ponds, tanks, and other derelict water bodies and ponds constructed for freshwater aquaculture. The pH of the freshwater should be around neutral and salinity below 5 ppt (parts per thousand).

Question 50.
What is Brackishwater aquaculture? What are the fishes cultured here?
Answer:
Brackish water fishes spend most of their life in river mouths (estuaries) backwaters, mangrove swamps, and coastal lagoons. Estuarine fish are more common in Bengal and Kerala. Culturing of animals in the water having salinity range 0.5 2 30 ppt are called as brackish water culture. Fishes cultured in brackish water are Milkfish (‘Chanos Chanos’), Sea bass (‘Koduva’), Grey mullet (‘Madavai ’), Pearl spots (‘Kari’meen) etc.

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

Question 51.
What is Mariculture? What are the fishes cultured here?
Answer:
Culturing of animals in the water salinity ranges from 30 – 35% is called Mariculture. Some fishes like Chanos sp, Mugil cephalus are cultured here.

Question 52.
What is metahaline culture?
Answer:
Culturing of animals in the salinity ranges from 36 – 40% is called Metahaline culture, eg: Brine shrimp (Artemia salina).

Question 53.
Write down the characteristics of cultivable fishes?
Answer:
Characteristics of cultivable fishes. The special characteristic features of cultivable fishes are:

  1. Fishes should have a high growth rate in a short period for culture.
  2. They should accept a supplementary diet.
  3. They should be hardy enough to resist some common diseases and infections of parasites.
  4. Fishes proposed for polyculture should be able to live together without interfering or attacking other fishes.
  5. They should have high conversion efficiency so that they can effectively utilize the food.

Question 54.
What are the types of cultivable fishes?
Answer:
Types of cultivable fish: Cultivable fish are of 3 types.

  1. Indigenous or native freshwater fishes (Major carps, Catla, Labeo, Clarias).
  2. Saltwater fishes acclimatized for freshwater (Chanos, Mullet).
  3. Exotic fishes or imported from other counties (Common carps).

Question 55.
Why carps have proved to be the best suited for culture in India?
Answer:
Major carps have proved to be best suited for culture in India because of the carps.

  1. Feed on zooplankton and phytoplankton, decaying weeds, debris, and other aquatic plants.
  2. They can survive in turbid water with slightly higher temperatures.
  3. Can tolerate O2 variations in water.
  4. Can be transported from one place to another easily.
  5. They are highly nutritive and palatable.

Question 56.
What are the external factors which affect fish culture?
Answer:
External factors affecting fish culture: The factors that affect fish culture are temperature, light rain, water, flood, water current, turbidity of the water, pH hardness, salinity, and dissolved O2. Light and temperature also play an important role in fish breeding.

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

Question 57.
What are the two types of breeding among fishes?
Answer:
Natural breeding and induced breeding.

Question 58.
Write about the induced breeding method in fishes?
Answer:
Induced breeding: The fish seed is commonly collected from breeding grounds but does not guarantee that all fish seeds belong to the same species. Hence advanced techniques have been developed to improve the quality of fish seed by the artificial methods of fertilization and induced breeding. Artificial fertilization involves the removal of ova and sperm from female and male by artificial mechanical process and the eggs are fertilized. For artificial fertilization, the belly of mature female fish is held upward. Stripping is done with the thumb of the right hand from the anterior to the posterior direction for the ejection of eggs due to force. In this way, eggs are collected separately. Further, the male fish is- caught with its belly downwards. The milt of fish is striped and collected separately, and then the eggs are fertilized.
Induced breeding is also done by hypohydration (removal of the pituitary gland).
The gonadotropin hormone (FSH and LH) secreted by the pituitary gland influences the maturation of gonads and spawning in fishes. The pituitary gland is removed from a healthy mature fish. The pituitary extract is prepared by homogenizing in 0.3% saline or glycerine and centrifuged for 15 minutes at 8000 rpm.
The supernatant is injected intramuscularly at the base of the caudal fin or intra-peritonealy ‘ at the base of pectoral fin. Male and female fishes start to spawn (release of gametes) and eggs are fertilized. The fertilized eggs are removed from the spawning place and kept into hatching hapas.

Question 59.
What is composite fish farming or polyculture?
Answer:
Few selected fishes belonging to different species are stocked together in proper proportion in a pond. This mixed farming is termed composite fish farming or polyculture.

Question 60.
What are the advantages of polyculture?
Answer:
The advantages of polyculture:

  1. All available niches are fully utilized.
  2. Compatible species do not harm each other.
  3. No competition among different species is found.
  4. Catla catla, Labeo rohita and Cirrhinus mrigala (surface feeder) are the commonly used fish species; for composite fish farming.

Question 61.
What are the different fishing methods carried out to harvest fish?
Answer:
Different methods of fishing are carried out to harvest fish. These include Stranding, Angling, Traps, Dipnets, Cast nets, Gillnets, Drag nets, and purse nets.

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

Question 62.
What are exotic fishes? Give example.
Answer:
The fishes imported into a country for fish culture are called exotic fishes and such fish culture is known as exotic fish culture. Examples of such exotic fishes introduced in India are Cyprinus carpio and Oreochromis mossambicus.

Question 63.
Write about some of the fish by-products in brief.
Answer:

  1. Fish oil is the most important fish by-product. It is derived from fish liver and from the fish body. Fish liver oil is derived from the liver which is rich in vitamin A and D, whereas fish body oil has a high content of iodine, not suitable for human consumption, but is used in the manufacture of laundry soaps, paints, and cosmetics.
  2. Fish meal is prepared from fish waste after extracting oil from the fish. The dried wastes are used to prepare food for pigs, poultry, and cattle. The wastes obtained during the preparation of fish meals are widely used as manure.
  3. Isinglass is a high-grade: collagen produced from dried air bladder or swim bladder of certain fishes viz. catfish and carps. The processed bladder which is dissolved in hot Water forms gelatin having adhesive property: It is primarily used for clarification of wine, beer, and vinegar.

Question 64.
What are the different types of prawn fishery?
Answer:

  1. Shallow water prawn fishery – located on the west coast restricted to shallow waters.
  2. Estuaries and backwaters or saline lake prawn fishery – The area of production of prawns are the backwaters seen along the Western coast, Ennur, Pulicat, Ohilka lake, and Estuaries of Ganga and Brahmaputra rivers.
  3. Freshwater prawn fishery – Prawns are caught from the rivers and lakes throughout India.
  4. Marine prawn fishery – Most of the marine prawns are caught along the Indian coast belonging to the family Penaeidae.

Question 65.
Mention the names of some species of prawn?
Answer:
Penaeus indicus, Penaeus monodon, Metapenaeus dobsoni and Macrobrachium rosenbergii.

Question 66.
How the freshwater prawn “Macrobrachium rosenbergii” is cultured?
Answer:
Macrobrachium rosenbergii is commonly seen in rivers, fields, and low-saline estuaries. The prawn collected from ponds, rivers, and paddy fields is transferred to the tanks which are aerated. For fertilization, one pair Of prawn are kept in a separate tank. After mating; the eggs are laid. Spawning tanks of different sizes should be prepared with proper aeration. Temperature (240 C – 300 Q arid pH (7-8) should be maintained in the hatching tank. The eggs hatch into first and second-stage larva. Artificial feed is supplied. Young ones of 5cm length (60 days old) can be reared in fresh or slightly brackish water ponds and rice fields. Harvesting of prawns can be done twice a year.

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

Question 67.
How pearl formation occurs?
Answer:
When a foreign particle accidentally enters into the space between the mantle and shell of the oyster, it adheres to the mantle. The mantle epithelium encloses it like a sac and starts to secrete concentric layers of nacre around it as a defensive mechanism. Nacre is secreted continuously by the epithelial layer of the mantle and is deposited around the foreign particle and over a period of time the formation of repeated layers of calcium carbonate makes them hard and glossy pearl. When the pearl enlarges the oyster dies. The shell is then carefully opened and the pearls are manually separated and graded.

Question 68.
How pearls are cultured artificially in the pearl industry?
Answer:
Programming of Pearl Industry and Artificial Insertion of Nucleus: This can be achieved by an artificial device to insert the nucleus as the foreign particle in the shell of oyster has proved useful for the production of pearls in greater numbers.

  1. Collection of oysters: Oysters are caught by special types of cages (84 x 54 x 20 cm) by covering a heavy wire frame with two-centimeter wire mesh. This cage is dipped into a sand-cement mixture providing a rough surface to the cages to which free-swimming spat get easily stuck up. These cages are suspended at a depth of 6 meters. From July to November, where spats are easily available. These collected oysters are now transferred to rearing cages.
  2. Rearing of oysters: The collected oysters are stocked and reared in a special type of cage called a rearing cage. These cages are well protected from enemies of oysters like Octopus, Eel, Devil fishes, etc. The collected oysters are first cleaned and then placed into the culture cages for a period of about 10 to 20 days to recover from the strain due to excessive handling and for the physiological adjustment to the shallow water conditions.
  3. Insertion of the nucleus: In this method, a piece of the mantle of living oyster is cut off and inserted together with a suitable nucleus inside the living tissue of another oyster. Following steps are taken for the insertion of the nucleus.
    (a) Fitness of oysters for operation: The selected oysters for the insertion of the nucleus should be healthy and strong enough to overcome the stress during operation.
    (b) Preparation of graft tissues: The piece of tissue which is inserted inside the mantle is called as ‘GRAFT’ tissue. The outer edges of these graft squares must be known because nacre secreting cells are found only on the outer surface of the mantle so it is essential to keep the outer surface in contact with the inserted nucleus.
    (c) Preparation of nucleus: Any small particle may function as a nucleus to initiate the pearl formation but it is reported that calcareous nucleus is the best because the deposition of nacre was found to be more on the calcareous nucleus.
    (d) Insertion of the nucleus: For the insertion of the nucleus, oysters are fixed in a desk clamp in the position of the right valve facing upward. Mantle folds are smoothly touched to expose the foot and the main body mass, followed by an incision into the epithelium of the foot and a slender channel into the main mass one graft tissue which functions as a bed for the nucleus.
    (e) Post-operation care: Nucleated oysters are placed into cages and suspended into seawater and attached with floating rafts to a depth of 2 to 3 meters for about 6 to 7 days to recover from the shocks due to operation. This period of 6 to 7 days is known as the ‘Recovery period’. About 3000 to 3600 nucleated oysters are kept in different cages suspended in seawater at 2 to 3 meters depth for 3 to 6 years and undisturbed except at the time of clearing and inspection.
  4. Harvesting of pearl: Pearls are harvested in the month of December to February which may slightly vary according to climatic conditions. After the completion of 3 years of the insertion of a nucleus, pearl oysters are harvested from the sea and the pearls are taken out from the shell.
  5. Clearing of pearls: After taking out the pearls from the oyster’s shell they are washed properly, cleared with the soap solution.

Question 69.
Write the composition of pearl.
Answer:
Composition of pearl: Pearl comprises water, organic matter, calcium carbonate, and residue.

  1. Water: 2 – 4%
  2. Organic matter: 3.5-5.9%
  3. Calcium Carbonate: 90%
  4. Residue: 0.1 – 0.8%, Carbonate: 90%.

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

Question 70.
What is meant by Animal husbandry?
Answer:
Animal husbandry is the practice of breeding and raising livestock cattle like cows, buffaloes, and goats and birds, etc., that are useful to human beings.

Question 71.
What are the parameters to be taken into account to maintain dairy and poultry farms?
Answer:
Parameters such as adequate ventilation, temperature, sufficient light, water, and proper housing accommodation should be taken into account to maintain dairy and poultry farms.

Question 72.
Write the objectives of animal breeding?
Answer:
Objectives of Animal breeding:

  1. To improve the growth rate.
  2. Enhancing the production of milk, meat. Egg etc.
  3. Increasing the quality of animal products.
  4. Improved resistance to diseases.
  5. Increased reproductive rate.

Question 73.
What is outcrossing?
Answer:
Outcrossing: It is the breeding between unrelated animals of the same breed but, having no common ancestry. The offspring of such a cross is called outcross. This method is suitable for breeding animals below average in productivity.

Question 74.
What is artificial insemination?
Answer:
Artificial insemination: Artificial insemination is a technique in which the semen collected from the male is injected into the reproductive tract of the selected female. Artificial insemination is the economical measure where fewer bulls are required and maximum use can be made of the best sire.

Question 75.
What is thawing?
Answer:
Thawing means to melt or become liquid. When the semen collected for artificial insemination is taken to far-off places/stored for a long time in the frozen condition it should be brought to room temperature slowly before use. This process is called thawing.

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

Question 76.
What is MOET? Write when this method is followed?
Answer:
Multiple ovulation embryo transfer technology (MOET): It is another method of propagation of animals with desirable traits. This method is applied when the success rate of crossing is low even after artificial insemination. In this method, Follicle-stimulating hormone (FSH) is administered to cows for inducing follicular maturation and superovulation. Instead of one egg per cycle, 6-8 eggs can be produced by this technology. The eggs are carefully recovered non-surgically from the genetic mother and fertilized artificially. The embryos at 8-32 celled stages are recovered and transferred to a surrogate mother. For*another round -of ovulation, the same genetic mother is utilized. This technology can be applied to cattle, sheep, and buffaloes.

Question 77.
How are cattle classified?
Answer:
Cattles are classified under three groups based on the purpose they serve to man. They are:

  1. Dairy breeds or Milk breeds: They are high milk yielders with extended lactation, eg: Sindhi, Gir, Sahiwal, Jersy, Brown Swiss, Holstein cattle.
  2. Draught purpose breeds: Bullocks are good for draught purposes, eg: Kangayam, Malvi.
  3. Dual Purpose breeds: Cows are meant for yielding more milk and bullocks are used for better drought purposes, eg: Ongole, Hariana.

Question 78.
Mention the names of the diseases of cattle.
Answer:
The main diseases of dairy cattle are rinderpest, foot and mouth disease, cowpox, hemorrhagic fever, anthrax.

Question 79.
What is poultry fanning?
Answer:
Poultry farming is essential for the purpose of meat, eggs, and feather production.

Question 80.
Some of the chicken breeds are of egg layers and are mainly farmed for the production of eggs. Name the egg layers and write their characters.
Answer:
Egg layers: These are farmed mainly for the production of eggs.
Leghorn: This is the most popular commercial breed in India and originated in Italy. They are small, compact with a single comb and wattles with white, brown, or black color. They mature early and begin to lay eggs at the age of 5 or 6 months. Hence these are preferred in commercial farms. They can also thrive well in dry areas.
Chittagong: It is the breed chiefly found in West Bengal. They are golden or light yellow colored. The beak is long and yellow in color. Ear lobes and wattles are small and red in color. They are good egg layers and are delicious.

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

Question 81.
Write the characters of white Plymouth rock.
Answer:
White Plymouth rock: They have white plumage throughout the body. It is commonly used in broiler production. This is an American breed. It is a fast-growing breed and well suitable for growing intensively in confined farms.

Question 82.
Write the special characteristic features of Aseel?
Answer:
Aseel: This breed is white or black in color. The hens are not good egg layers but are good in the incubation of eggs. It is found in all states of India. Aseel is noted for its pugnacity, high stamina, and majestic gait, and dogged fighting qualities. Although poor in productivity, this breed is well-known for its meat qualities.

Question 83.
Given an example for the ornamental breed of ‘ chicken and write its features.
Answer:
Silkie: It is a breed of chicken that has a typical fluffy plumage, which is said to feel like silk and satin. The breed has numerous additional special characters, such as black skin and bones, blue earlobes, and five toes on each foot, while the majority of chickens only have four. They are exhibited in poultry shows and come out in various colors. Silkies are well recognized for their calm, friendly temperament. Silkie chicken is especially simple to maintain as pets.

Question 84.
What are the different methods of poultry farming?
Answer:
The types of poultry farming are Free-range farming. Organic method, Yarding method, Battery cage method, and Furnished cage method.

Question 85.
Explain the steps involved in rearing chicken?
Answer:
There are some steps involved in rearing chicken.
Selection of the best layer: An active intelligent-looking bird, with a bright comb, not obese should be selected.
Selection of eggs for hatching: Eggs should be selected very carefully. Eggs should be fertile, medium-sized, dark brown shelled and freshly laid eggs are preferred for rearing. Eggs should be washed, cleaned, and dried.
Incubation and hatching: The maintenance of newly laid eggs in optimum condition till hatching is called incubation. The fully developed chick emerges out of the egg after an incubation period of 21 – 22 days. There are two types of incubation namely natural incubation and artificial incubation. In the natural incubation method, only a limited number of eggs can be incubated by a mother hen. In artificial incubation, more eggs can be incubated in a chamber (Incubator).
Brooding: Caring and management of young chicks for 4-6 weeks immediately after hatching is called brooding. It can also be categorized into two types namely natural and artificial brooding.
The housing of Poultry: To protect the poultry from sun, rain, and predators it is necessary to provide housing to poultry. Poultry house should be moisture-proof, rat proof and it should be easily cleanable and durable.
Poultry feeding: The diet of chicks should contain an adequate amount of water, carbohydrates, proteins, fats, vitamins, and minerals.

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

Question 86.
What are the main products and byproducts of poultry farming?
Answer:

  1. The main products of poultry farming are eggs and meat.
  2. The feathers of poultry birds are used for making pillows and quilts. Droppings of poultry can be used as manure in fields.
  3. A number of poultry byproducts like blood-meal, feather meal, poultry by-product meal, and hatchery by-product meal are used as good sources of nutrients for meat producing animals and poultry.

Question 87.
Name the diseases that affect poultry animals.
Answer:
Ranikhet, Coccidiosis, and Fowlpox are some common poultry diseases.

Question 88.
Write the benefits of keeping poultry. Benefits of Poultry farming:
Answer:
The advantages of poultry farming are-

  1. It does not require high capital for construction and maintenance of poultry farming:
  2. It does not require a big space.
  3. It ensures a high return of investment within a very short period of time.
  4. It provides fresh and nutritious food and has a huge global demand.
  5. It provides employment opportunities for the people.

Question 89.
Mention the native breeds and exotic breeds of duck.
Answer:
The native one includes Indian Runner and Syhlet meta. The exotic breeds include Muscori, Pekin, Aylesbury and Campbell.

Question 90.
Ramu has reared about 60 to 70 ducks of his own. In what way he is benefited from duck farming.
Answer:
Advantages of duck farming: They can be reared in small backyards where water is available and needs less care and management as they are very hardy. They can adapt themselves to all types of environmental conditions and are breed for feed efficiency, growth rate, and resistance to diseases.

Question 91.
Why should we breed animals?
Answer:
Through animal breeding, improved breeds of animals can be produced by improving their genotype through selective breeding.

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

Question 92.
How can you identify healthy cattle?
Answer:
Healthy cattle appear bright, alert, and active in their movement with a shiny coat.

Question 93.
Define Hapa?
Answer:
Hapa is a cage-like, rectangular, or square net impoundment placed in a pond for holding fish for various purposes. They are made of fine mesh netting material.

Question 94.
What is drilosphere?
Answer:
Drilospfiere is the part of the soil influenced by earthworm secretions, burrowing, and castings.

Question 95.
What is a biological indicator?
Answer:
The biological indicator refers to organisms, species or communities whose characteristics show the presence of specific environmental conditions.

Choose the correct answer.

1. A branch of science that deals with economically useful animals is called:
(a) apiculture
(b) horticulture
(c) economic zoology
(d) aquaculture
Answer:
(c) economic zoology

2. ……….. is the primary goal of vermiculture.
(a) Vermiwash
(b) Vermi compost
(c) Voltinism
(d) Manure production
Answer:
(b) Vermi compost

3. ………… is called biological indicators of soil fertility.
(a) Silkworm
(b) Honeybee
(c) Earthworm
(d) Lac insect
Answer:
(c) Earthworm

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

4. ………. are the earthworms, which dwell on the surface and feed on organic matter.
(a) Humus formers
(b) Humus feeders
(c) Vermi composers
(d) Soil improvers
Answer:
(a) Humus formers

5. Lampito mauritii are the ……….. species of earthworms.
(a) endemic species
(b) extinct species
(c) exotic species
(d) notho species
Answer:
(a) endemic species

6. ……… is a liquid collected after the passage of water through a column of vermibed.
(a) Hydrophonics
(b) Vermiwash
(c) Vermicompost
(d) Mucilage
Answer:
(b) Vermiwash

7. Vermiwash is obtained from the …………. formed by earthworms
(a) compost unit
(b) bunds
(c) drilospheres
(d) soil
Answer:
(c) drilospheres

8. Which of the following statement is not correct.
The main components of sericulture
(a) Cultivation of food plants
(b) The mass emergence of larvae from the egg in search of host plant is called swarming
(c) Rearing of worms
(d) Reeling and spinning of silk.
Answer:
(b) The mass emergence of larvae from the egg in search of host plant is called swarming

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

9. The ‘Muga Silk’ is produced from the ………. species of silkmoth.
(a) Bombyx mori
(b) Antheraea mylitta
(c) Antheraea assamensis
(d) Attacus ricini
Answer:
(c) Antheraea assamensis

10. The preferred food leaves of the silkworm species Attacus ricini is:
(a) mulberry
(b) champa
(c) castor
(d) aijun
Answer:
(c) castor

11. Which of the following state in which Mulberry silk is produced?
(a) Tamilnadu
(b) Nagaland
(c) West Bengal
(d) Assam
Answer:
(a) Tamilnadu

12. A single female moth of silkworm lays …………. number of eggs depending upon the climatic conditions.
(a) 40-50
(b) 400-500
(c) 1-24
(d) 2-3
Answer:
(b) 400-500

13. The caterpillars of silkworm developed …………. type of mouth parts adapted to feed easily on the mulberry leaves.
(a) maxillary
(b) mandibulate
(c) cutter
(d) sickle
Answer:
(b) mandibulate

14. Name the species that produces large amount of silk is:
(a) Attacus ricini
(b) Bombyx mori
(c) Antheraea mylitta
(d) Antheraea assamensis
Answer:
(b) Bombyx mori

15. The cultivation of mulbeny is Called:
(a) sericulture
(b) apiculture
(c) horticulture
(d) moriculture
Answer:
(d) moriculture

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

16. The method of obtaining silk thread from the cocoon is known as
(a) pre-cocoon processing
(b) post-cocoon processing
(c) reeling
(d) cooking
Answer:
(b) post-cocoon processing

17. The process of killing the cocoon is called:
(a) reeling
(b) stifling
(c) cooking
(d) rearing
Answer:
(b) stifling

18. The process of removing die threads from the killed cocoon is called:
(a) reeling
(b) stifling
(c) cooking
(d) bundling
Answer:
(a) reeling

19. Pebrine is a dangerous disease caused by:
(a) Nosema bombycis
(b) Streptococcus
(c) Baculovirus
(d) Staphylococcus
Answer:
(a) Nosema bombycis

20. Worker bee lives in a chamber called:
(a) brood cell
(b) drone cell
(c) worker cell
(d) sub cells
Answer:
(c) worker cell

21. Match the correct pair:

1. Metabolic process (a) Liquid from vermibed
2. Classification of animals (b) Embryologist
3. Early development stage (c) Physiologist
4. Vermitech Taxonomists
5. Vermiwash (e) Bio-remediation of soil

(a) 1 -(d), 2-(c), 3-(e), 4-(b), 5-(a)
(b) 1-(c), 2-(d), 3-(b), 4-(a), 5-(e)
(c) 1-(e), 2-(a), 3-(d), 4-(c), 5-(b)
(d) 1-(a), 2-(b), 3-(c), 4-(d), 5-(e)
Answer:
(b) 1-(c), 2-(d), 3-(b), 4-(a), 5-(e)

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

22. The nectar collected from the flowers and is stored in the stomach region of the worker bee, is transformed into honey by the enzyme called:
(a) enterokinase
(b) peptidase
(c) invertase
(d) transferase
Answer:
(c) invertase

23. The process of leaving the colony by the queen with a large group of worker bees to form a new colony is called:
(a) nupital flight
(b) migration
(c) swarming
(d) flocking
Answer:
(c) swarming

24. Match the following:

1. Apis dorsata (a) Little bee
2. Apis florea (b) Rock bee
3,Apisindica (c) European bee
4. Apis mellifera (d) African bee
5. Apis adamsoni (e) Indian bee

(a) 1 -(a), 2-(b), 3-(d), 4-(e), 5-(c)
(b) 1 -(c), 2-(d), 3-(b), 4-(a), 5-(e)
(c) 1-(b), 2-(a), 3-(e), 4-(c), 5-(d)
(d) 1 -(d), 2-(c), 3-(a), 4-(b), 5-(e)
Answer:
(c) 1-(b), 2-(a), 3-(e), 4-(c), 5-(d)

25.. ……….. is the most important part of the Langstroth bee hive.
(a) Inner cover
(b) Top cover
(c) Bottom board
(d) Brood chamber
Answer:
(d) Brood chamber

26. ………. is a device made of fine nettings to protect the bee keeper form bee sting.
(a) Bee gloves
(b) Bee veil
(c) Bee brush
(d) Comb foundation
Answer:
(b) Bee veil

27. Which of the following statement is incorrect regarding honey?
(a) It is an aromatic sweet material
(b) It is used as an antiseptic and as a sedative
(c) The resinous chemical substance present is called propolis
(d) It is generally used in Ayurvedic and unani systems of medicines
Answer:
(c) The resinous chemical substance present is called propolis

28. ……….. is secreted by the abdomen of the worker bees at the age of two weeks.
(a) Beewax
(b) Honey
(c) Lac
(d) Pollen
Answer:
(a) Beewax

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

29. Lac insect Tachardia lacca is previously known as:
(a) Bombyx mori
(b) Apis florea
(c) Laccifer Lacca
(d) Penaeus Indicus
Answer:
(c) Laccifer Lacca

30. Match the following:

1. S36,G2,G4 (a) Spinning wheels
2.Voltinism (b) Silk road
3. Gharakhas (c) Number of broods
4. Verini compost (d) Mulberry varieties
5. 7000 mile (e) Plant nutrients

(a) 1-(a), 2-(b), 3-(d), 4-(e), 5-(c)
(b) 1-(d), 2-(c), 3-(a), 4-(e), 5-(b)
(c) 1 -(b), 2-(d), 3-(a), 4-(c), 5-(e)
(d) 1-(b), 2-(a), 3-(d), 4-(e), 5-(c)
Answer:
(b) 1-(d), 2-(c), 3-(a), 4-(e), 5-(b)

31. Which one of the following is not related to Lac insect:
(a) Lac insect sucks plant juices, grows and secretes Lac
(b) The quality of lac depends on the quality of the host plant
(c) After copulation, the male insect dies
(d) It is a functional female which feeds on royal jelly.
Answer:
(d) It is a functional female which feeds on royal jelly.

32. The “seed lac” is sub dried and then melted to produce:
(a) Ari lac
(b) Stick lac
(c) Shellac
(d) Cerelac
Answer:
(c) Shellac

33. Assertion: Aquaponics is a technique which is a combination of aquaculture and hydroponics.
Reason: In this system plant waste and decays are utilized by fishes as food
(a) Assertion and reason is correct but not related.
(b) Assertion and reason is incorrect but related.
(c) Assertion and reason is correct but related.
(d) Assertion and reason is incorrect but not related.
Answer:
(c) Assertion and reason is correct but related.

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

34. Match the following:

1. Ari lac (a) Acacia nilotica
2. Stick lac (b) Acacia catechu
3. Khair (c) Schleichera oleosa
4. Kamvelai (d) Immature harvesting
5. Karangalli (e) Cut from the host plant

(a) 1 -(b), 2-(c), 3-(d), 4-(e), 5-(a)
(b) 1-(e), 2-(d), 3-(c), 4-(b), 5-(a)
(c) l-(e), 2-(b), 3-(a), 4-(d), 5-(c)
(d) 1 -(d), 2-(c), 3-(b), 4-(a), 5-(c)
Answer:
(d) 1 -(d), 2-(c), 3-(b), 4-(a), 5-(c)

35. Aqua vertica is otherwise known as
(a) Vertical aquaponics
(b) Plants are kept in PVC pipe holes
(c) Growing plants in clay pellets
(d) Raft based method.
Answer:
(a) Vertical aquaponics

36. Choose the correct statement from the below
(a) Use of pesticides is avoided in aquaphonics
(b) Growth of weeds is more in aquaphonics
(c) Estuarine fishes are more common in Tamilnadu and Pondichery
(d) Exotic fishes are native breeds.
Answer:
(a) Use of pesticides is avoided in aquaphonics

37. Cultivable fishes like tilapia, trout, koi, gold fish, bass, etc are cultured in aquaphonics – say this statement is true or false.
Answer:
true

38. Match the following:

1. Artemia (a) Benchijal
2. Catla (b) High quality pearls
3. Spawn collecting net (c) Indigenous freshwater fishes
4. High grade collagen (d) Brine shrimp
5. Pinctada (e) Isinglass

(a) 1-(e), 2-(d), 3-(a), 4-(b), 5-(c)
(b) 1-(d), 2-(c), 3-(a), 4-(e), 5-(b)
(c) 1-(b), 2-(a), 3-(c), 4-(e), 5-(d)
(d) 1-(e), 2-(c), 3-(d), 4-(a), 5-(b)
Answer:
(b) 1-(d), 2-(c), 3-(a), 4-(e), 5-(b)

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

39. The spawn collecting net is called:
(a) Benchijal
(b) Hapas
(c) Fishnet
(d) Dipnets
Answer:
(a) Benchijal

40. Management of fish farm includes
(a) Fish seed – nursery pond- stocking pond – harvesting
(b) Breeding pond – fish seed-hatching pit – nursery pond – rearing pond – stocking pond –harvesting
(c) Breeding pond – nursery pond- rearing pond- stocking pond- harvesting.
(d) Fish seed – hatching pit- rearing pond-stocking pond-harvesting
Answer:
(b) Breeding pond – fish seed-hatching pit – nursery pond – rearing pond – stocking pond –harvesting

41. The newly hatched fries of fishes are transported from the hatching happa to nursery ponds where they grow into:
(a) Hatchling
(b) Larva
(c) Fingerlings
(d) Tadpoles
Answer:
(c) Fingerlings

42. Say which statement of the following is not correct.
(a) Selected fishes of different species are stocked together in a pond is called composite fish farming
(b) Catla, Rohita, are the commonly used fishes for composite fish farming.
(c) The fishes imported into the country are called exotic fishes.
(d) Parasitic infestations and microbial infections cannot be found and treated among fishes.
Answer:
(d) Parasitic infestations and microbial infections cannot be found and treated among fishes.

43 is the fish product rich in Vitamin A and D.
(a) Fish meal
(b) Fish oil
(c) Ising glass
(d) Dried fish
Answer:
(b) Fish oil

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

44. ……….. are the aquatic crustacean their flesh contains more glycogen protein with low fat content.
(a) Prawns
(b) Oysters
(c) Crayfish
(d) Crabs
Answer:
(a) Prawns

45. ……….. is commonly seen in rivers and low saline estuaries.
(a) Metapenaeus dobsoni
(b) Panaeus indicus
(c) Panaeus monodon
(d) Macrobrachium rosenbergii
Answer:
(d) Macrobrachium rosenbergii

46. High quality of pears are obtained from pearl oysters of;
(a) Lamellidens
(b) Olympia oyster
(c) Pinctada
(d) Sydney rock oyster
Answer:
(c) Pinctada

47. …………. breed is the smallest breed of cow.
(a) Brown Swiss
(b) Jersey
(c) Sindhi
(d) Vechur
Answer:
(d) Vechur

48. The most popular commercial chicken breed in India is ………. which thrive well in dry areas.
(a) Aseel
(b) White Plymouth rock
(c) Brahma
(d) Leghorn
Answer:
(d) Leghorn

49. Fast growing chicken breed is:
(a) Chittagong
(b) White Plymouth rock
(c) Wyandotte
(d) Karaknath
Answer:
(b) White Plymouth rock

50. ……….. is a type of chicken breed known for its pugnacity.
(a) Aseel
(b) Brahma
(c) Busra
(d) Leghorn
Answer:
(a) Aseel

51. Which is the ornamental breed of chicken of the following?
(a) Chittagong
(b) Leghorn
(c) Aseel
(d) Silkie
Answer:
(d) Silkie

TN Board 11th Bio Zoology Important Questions Chapter 12 Trends in Economic Zoology

52. Match the following:

1. Egg layers (a) White Plymouth rock
2. Broiler type (b) Silkie
3. Dual purpose breed (c) Leghorn
4. Game breeds (d) Brahma
5. Ornamental breeds (e) Aseel

(a) 1-(b), 2-(a), 3-(e), 4-(c), 5-(d)
(b) 1 -(a), 2-(c), 3-(b), 4-(e), 5-(d)
(c) 1 -(d), 2-(e), 3-(c), 4-(b), 5-(a)
(d) 1 -(c), 2-(a), 3-(d), 4-(e), 5-(b)
Answer:
(d) 1 -(c), 2-(a), 3-(d), 4-(e), 5-(b)

53. Which of the following statement is true?
(a) The most common and commercially farmed birds are chicken, ducks, goose, patridges, Guinea fowl, Emu, etc.
(b) Broiler type chicken are well known for its slow growth and hard quality of meat
(c) Aseel hens are good egg layers, but are not good in incubation of eggs
(d) Silkies are well recognized for its majestic look and fighting qualities.
Answer:
(a) The most common and commercially farmed birds are chicken, ducks, goose, patridges, Guinea fowl, Emu, etc.