Class 12 Biology Chapter 16 Bioresources of Assam

Class 12 Biology Chapter 16 Bioresources of Assam The answer to each chapter is provided in the list so that you can easily browse through different chapters Assam Board HS 2nd Year Biology Chapter 16 Bioresources of Assam Question Answer.

Class 12 Biology Chapter 16 Bioresources of Assam

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Also, you can read the SCERT book online in these sections Solutions by Expert Teachers as per SCERT (CBSE) Book guidelines. These solutions are part of SCERT All Subject Solutions. Here we have given Assam Board Class 12 Biology Chapter 16 Bioresources of Assam Solutions for All Subjects, You can practice these here.

(E). Short Answer Questions (3 Marks Each) : 

Q.1. “Forests are full of future genetic resources”. Explain the statement. 

Ans : Forest are the prime sources of plants and animals. It is the source of endangered plants as well as the animals. Moreover the plants may have medicinal, ornamental values. By the process of hybridization of nearby species we can get new plant variation. Hence the forest are considered full of future genetic resources. 

Q.2. Give the scientific names mentioning their families of three popular and important timber yielding plants of Assam. 

Ans :     

Q.3. Write the scientific names with their utility of the following plants. 

(a) Rauwolfia.

(b) Neem.

(c) Cinchona.

(d) Teak.

(e) Sal.

(f) Indian red wood (sisso) 

Ans :         

Q.4. Write briefly how muga silk is obtained from the cocoon. 

Ans : To obtain muga silk from the cocoon, the cocoon should be boiled in alkaline water i.e. soda water (traditionally khar pani) to remove the glue of the cocoon. It makes the fibre soft. Before boiling the cocoon should be kept in sunlight to kill the chrysalid. Now the cocoon is kept in lukewarm water and the spinning is done (generally by Takuri) and reeling (Traditionally by Jatar) by machine. The reeling machine is called ‘bhir. After reeling the fibre is ready for weaving. 

Q.5. Why eri silkworm is called polyphagous? State the different 5. food plants of eri silk worms. 

Ans : The eri silkworm is called the polyphagus because it depends on more than one plant for food, not only one. 

The food plants or host plants may be of two types : 

(a) Primary host plant, eg. Castor 

(b) Secondary host plant. eg. Kesseru, Tapioca etc. 

Q.6. “Assam is very rich in cervicogenic resources”. Explain the statement.

Ans : Assam is the homeland of different silk worms like pat polu or mulberry silk worm, muga polu or muga silk worm, eri polu or eri silk worm and tasar silk worm. Except muga other species were domesticated and reared as cottage industry. It was very popular among the tribals of Assam. Now a days commercially the silkworm rearing is taking place. Moreover, the climatic condition of Assam is also favourable for the rearing of host plants of silkworm. Hence, is called that Assam is very rich in cervicogenic resources. 

Q.7. Describe a case study of integrated Waste Water Treatment. 

Ans : The industrial and municipal waste waters are treated in effluent treatment plant before their discharge in water bodies. This can be done by –

(a) Primary treatment includes the mechanical screening and sedimentation of undissolved solids. 

(b) Secondary treatment includes the chlorination of water to kill the germs. 

(c) Advance waste water management includes the addition of salt like nitrates and phosphates and removed by precipitation technique water is new pure to drink. 

Integrated waste water treatment case study : Sewage and waste water can be treated by an integrated waste water treatment process developed in Arcata of California by some biologists of Humboldt State University. This treatment process is a combination of artificial and natural processes. The cleaning occurs in two stages and these are: 

(i) Conventional method in which filtering, sedimentation and chlorine treatment are adopted to remove the organic remains, microbes etc. The treated water contains heavy metals and other pollutants and so another method namely. 

(ii) Innovative approaches are applied in which a series of six connected marshes over 60 hectares of marshland are developed. These marsh lands are seeded with bacteria, fungi, algae and plants for neutralization, absorption and assimilation of the pollutants. The naturally purified water is then allowed to flow. The marshes also constitute a sanctuary where aquatic animals, varieties of fishes and birds make their habitat areas.

Q.8. Discuss the anatomical characters of timber produced from teak and hill teak, mention their botanical names. 

Ans : Teak is a large deciduous plant of great timber value. The wood consist of small whitish sapwood and large brown to dark heartwood. 

The teak is very strong and durable because of its large oil contents in The botanical name is Tectona grandis.

(F). Long Answer Questions (5 Marks Each) :

Q.1. Describe the life cycle and rearing of muga silk moth. 

Ans : The life cycle and rearing of muga silk moth are : 

(a) Life cycle : The life cycle of muga silk moth includes the four stages. 

(i) Eggs : After mating the female lays about 250 eggs which are oval and lays in clusters due to the presence of sticky substance. In culture, the eggs are collected and washed with 2% formalin to kill the germs. 

(ii) Larva : Normally after 9-10 days, eggs hatches out to larva. The newly hatched larvae are black and yellow coloured and feed on young leaves. The larva undergoes four times moulting resulting 5 inster stages. The fifth instar stage is highest developed carval stage. 

(iii) Pupa : The full grown larvae stop feeding and stop movement. They spin threads by rotating their head forming cocoon. Cocoon formation is completed within 3/4 days. Within the cocoon the larvae is transformed into pupa. It is of brown red coloured within the cocoon the pupa undergoes metamorphosis for the formation of adult. During rearing, the cocoons are killed so that we get good fibres from the cocoon. 

(iv) Adult : After emergence of male and female, the male moves in search of females only. The male, after successful mating died and female starts laying eggs. By the time of laying eggs is over, the females also die. 

In rearing, the females are tied with a kharika and the males are allowed to mate successfully with the females. After mating the male is falling down and female start laying eggs on the Kharika in a line. 

(b) Rearing : Rearing of muga silk moth can be done by feeding the host plants. Moreover the muga silk moth is semi domestic type. Generally after hatching the larvae are allowed to feed on the leaves and the fifth in star larvae are collected to form cocoon in side the house. 

The primary host plants : Som and Sualu. 

and the secondary host plants : Diglati, Bajramoni, Mezankari etc. 

Q.2. Write a note on disease of silkworm mentioning the causative organism of each disease. 

Ans : The common disease of silkworm are : 

(a) Pebrine : It is caused by Nosema bombycis protozoan. Here the infected larva becomes weak and the silk glands are not properly developed. Some black spots develops and hence is called as phutukia. 

(b) Flacherie : It is caused by viral infection which is followed by bacterial infection. It is very common in summer season. Traditionally it is called as mukhilaga. 

(c) Grasserie : It is due the climate change. Here the larvae become inactive. 

(d) Muscardine : It is a fungal disease and the infection starts in the egg stage. It is very common in pat polu and eri polu.

Q.3. Explain why northeast region of India specially Assam is regarded as very rich in plant resources. 

Ans : Assam, in North East India is very rich in biodiversity. It is regarded as the hot spot because Assam is the home land of may valuable plants and animals. In India, out of 315 families of gymnosperms about 200 families and found in Assam. Moreover different types of timber producing, silk or fibre colour producing, bamboo, cane, resin, lentils etc. are the product of plants or forests of Assam. Moreover, the forest gives us the scenic beauty and keeps the climate in natural and hence Assam is called the land of biological hot spot. 

Q.4. Discuss briefly giving your views how plant resources of Assam can be utilized for economic development of the people. 

Ans : Assam is one of the richest place.of India. It has very rich plant diversity. The forest of Assam has different species of bamboo, cane, medicinal plants, fibre plants, timber plants etc. 

Bamboo is used for different articles alongwith the house of people of Assam. Industrially raw material of paper industry. Cane is also used for furniture, and other domestic materials. A number of medicines are produced from the medicinal plants. Sal is used for the construction of bridges and railway sleeper. Sissoo is for the furniture, Gomari, teak etc are also for the furniture and household items. 

Pulse, mustardseed, teel, clove, olive etc. are also used for the production of oil which can support us economically. 

The economic crops includes rice, jute, sugarcane, cereals etc. 

Q.6. State briefly how water pollution can be controlled? 

Ans : Water pollution can be controlled. 

(i) Preventive measures : The following preventive measures should (1) 6. be observed : 

(a) Proper disposal of sewage so that it does not find its way into water bodies. 

(b) Abuse of water must be checked. 

(c) Discharge of effluents into rivers, lakes and sea should be strictly prohibited without treatment. 

(d) Oil spill should be prevented. 

(ii) Curative measures : 

(i) Using septic tanks, oxidation ponds, filter beds, waste water treatment plants, sewage treatment plants etc. Solid wastes may be removed before water is tipped into river or sea. The solid waste then can be converted into sludge which is a valuable fertilizer. 

(ii) For drinking purposes water is purified through various steps (9) including biological treatment and disinfection. 

(c) Industrial water can be made less polluted before discharge by biological treatment using water hyacinth. Water hyacinth has remarkable capacity to accumulate poisonous metals including radioactive substances. 

(d) Certain strains of bacteria can reduce the oil spill effect and can use up cyanides and heavy metals if judiciously used. 

(e) Scientific method of recycling all waste materials and effluents (a) can reduce water pollution to a great extent. 

Q.7. Discuss in brief giving their botanical names, parts used and purposes of uses of any five medicinal plants utilized in traditional practices by ethnic groups. 

Ans :           

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