EXERCISES

Q1. What do you mean by bioresource? What are the components of bioresources?
Answer: Bioresources are the products provided from the world of plants and animals that are essential for life and livelihood. They are a major component of natural resources, provided by nature, and useful to human beings and society in one way or another. The components of bioresources can be divided into two main kinds:

1. Plant resources
2. Animal resources

Q2. What is a biological hot spot? Justify the statements that Assam is a biological hot spot of the world.
Answer: A biological hotspot is a region that is extremely rich in biodiversity, containing a large number of endemic species (species found nowhere else in the world) but also facing a high level of threat from human activities such as deforestation, pollution, or habitat loss.

Assam is a biological hot spot because of the following reasons:

1. North East India, including Assam, is considered one of the most biologically diverse areas in the whole of South Asia.
2. The region has tropical rainforests and many different kinds of forest like evergreen, deciduous, swampy, and riparian.
3. It is full of innumerable varieties of plant species (future genetic resources).
4. Out of 315 Indian angiosperm families, about 200 families are found here.
5. This part of India serves as a centre of origin for economically important plants like rice, musa, citrus, mango, tea, and ginger.
6. Assam is the home of nearly 300 out of 400 total Indian orchid varieties.
7. Assam and the North Eastern Region account for approximately 50% of the total plant species of India.

Q3. What are the three basic requirements of human provides by plants?
Answer: Plants fulfill the three basic requirements of human life by providing:

1. Food – Grains, fruits, vegetables, and pulses come from plants and form our primary source of nutrition.
2. Clothing – Fibres like cotton, flax, and jute obtained from plants are used to make clothes.
3. Shelter – Wood, bamboo, and other plant materials are used for building houses and furniture.

Q4. Give the names of two major bioresources.
Answer: The two major types of bioresources are:

1. Plant resources – Include crops, trees, and medicinal plants that provide food, timber, fibre, and medicines.
2. Animal resources – Include livestock, fish, and other animals that provide meat, milk, leather, and other useful products.

Q5. What do you mean by ethnic medicine?
Answer: Ethnic medicine refers to the plant-medicines which are mostly used by ethnic tribal communities and rural people for the treatment of diseases. They utilize resources of the forests in a sustainable way and follow traditional practices for curing bodily disorders.

Q6. Write the Botanical names and uses of five medicinal plants available in your area.
Answer:

Q7. Write the Botanical names with family of five timber yielding plants available in Assam.
Answer:

Q8. State the utility of the following plants and mention their scientific names.
Answer:

Q9. Write the scientific name of sericogenus insects found in Assam with two primary host plants of each species.
Answer: The sericogenic insects found in Assam include Mulberry (Pat), Muga, Eri, and Tassar. The following table lists their scientific names and primary host plants:

Q10. ‘Sericulture is an agro-based industry.’ Explain with your opinion.
Answer: Sericulture is called an agro-based industry because it depends both on agriculture and industry. The agricultural part involves cultivating specific host plants like Som and Sualu for Muga silkworms or Castor plants for Eri silkworms, which provide food for the larvae. The industrial part includes rearing these silkworms to produce silk threads, which are processed and woven into fabrics for commercial use. Since sericulture combines farming activities with industrial production of silk, it is rightly considered an agro-based industry.

Q11. What are the differences between eri and muga worm rearing?
Answer: The main differences between Eri and Muga worm rearing are as follows:

1. Rearing Environment: Muga worms are reared outdoors under natural conditions, whereas Eri worms can be reared indoors with simple arrangements.
2. Primary Food Plant: Muga worms feed on Som and Sualu plants, while Eri worms mainly feed on Castor leaves.
3. Pupa/Cocoon: The cocoon of Muga is oval, brown, and pointed at one end, whereas that of Eri is white or creamy and soft.
4. Silk Extraction: Muga silk is reeled using a Bhir, whereas Eri silk is spun using a Chakra.

Q12. How many stages are there in the life history of silkworm? What kind of measures are taken in every stage?
Answer: There are four major stages in the life history of a silkworm: egg, larva, pupa, and adult.

Q13. Discuss the main disease of silkworm and suggest their protective measures.
Answer: The Muga and Eri silkworms suffer from similar diseases, which are more prevalent during summer.

Q14. Write the name of secondary host plants of eri and muga silkworm.
Answer:

1. Eri Silkworm (Philosamia ricini): Kaseru, Borkaseru, Tapioca
2. Muga Silkworm (Antheraea assama): Digloti, Mejankari, Bhomlati, Bajarmoni

Q15. How muga threads are obtained from the cocoons?
Answer: Muga threads are obtained through a process called reeling.

1. Selection: Cocoons are sorted to separate those kept for rearing from the rest (which are stifled).
2. Stifling and Boiling: The commercial cocoons are stifled to death and stored. The stored cocoons are then boiled in soda water to remove the glue.
3. Reeling: The silk fibres are reeled on Bhir (a device used for reeling, which requires skill).

Obtaining 1 kg of silk requires about 4000–4500 cocoons.

Q16. How silk is obtained from eri cocoon? Write briefly.
Answer: Silk is obtained from eri cocoons through a spinning process.

1. Stifling: The inner pupae of the commercial cocoons are stifled to death by heating.
2. Boiling: The cocoons are boiled to remove the glue.
3. Spinning: The fibres are then spinned on Chakra (a spinning device).

Q17. What kinds of facility should be provided to the matured larva for cocoon formation?
Answer: For cocoon formation, the matured larva should be provided with:

1. Clean dry twigs
2. Leaves of mango and jackfruit trees
3. Well-ventilated rooms
4. Clean and disinfected environment

Q18. The environment for muga and eri culture is favourable in Assam. Explain.
Answer: The environment in Assam is favorable for Muga and Eri culture due to rich biological resources and suitable climate.

1. Flora/Host Plants: Assam’s natural environment supports diverse flora, including necessary host plants such as Som and Sualu for Muga, and Castor for Eri.
2. Traditional Knowledge: The ethnic tribal communities of Assam have long practiced sericulture sustainably, making it an integral part of Assamese culture and livelihood.

Q19. Fill up the gaps:
(a) Muga silkworm is reared……………
(b) Disease pebrine is caused by ………………...
(c) Majankari is the secondary host plant of ………… silkworm.
(d) Bhir is used to obtain threads of ……….silkworm.
(e) Silkworm (moth) belongs to phylum …………. and order ……………
(f) Eggs of eri and muga are treated with …………. for disinfection.
(g) Female moth is tied on ………………for egg laying.
(h) The primary food plant of eri silkworm is ………….
(i) Philosamia ricini is the scientific name of…………moth.
(j) The fifth instar larva casts its skin for the last time inside the cocoon to form a ………….
Answer:

(a) Muga silkworm is reared outdoor.
(b) Disease Pebrine is caused by protozoan Nosema.
(c) Mejankari is the secondary host plant of Muga silkworm.
(d) Bhir is used to obtain threads of Muga silkworm.
(e) Silkworm (moth) belongs to phylum Arthropoda and order Lepidoptera.
(f) Eggs of Eri and Muga are treated with 2% formalin for disinfection.
(g) Female moth is tied on Kharika for egg laying.
(h) The primary food plant of Eri silkworm is Castor.
(i) Philosamia ricini is the scientific name of Eri moth.
(j) The fifth instar larva casts its skin for the last time inside the cocoon to form pupa.

Q20. State the differences between:
(a)Primary and secondary food plants.
(b) Eri and Muga silk insects.
(c) Pebrine and Flacheries disease.
Answer:

(a) Primary and Secondary Food Plants

1. Primary food plants are the main host plants on which silkworms are mainly reared and grow best, whereas secondary food plants serve as alternative or supplementary hosts.
2. Muga silkworms feed mainly on Som and Sualu, whereas they can also feed on Digloti, Mejankari, Bhomlati, and Bajarmoni as secondary hosts.
3. Eri silkworms prefer Castor as their primary food plant, whereas Kaseru, Borkaseru, and Tapioca act as secondary food plants.

(b) Eri and Muga Silk Insects

1. Muga silkworms are reared outdoors, whereas Eri silkworms can be reared indoors with simple facilities.
2. Muga worms feed on Som and Sualu, whereas Eri worms feed mainly on Castor leaves.
3. The male Muga moth has a slimmer abdomen and pointed forewings, whereas the female has blunt wings and a broader abdomen.
4. In Eri moths, the female is larger than the male, whereas size difference is less prominent in Muga moths.
5. Muga silk is reeled on Bhir, whereas Eri silk is spun on Chakra.

(c) Pebrine and Flacherie Diseases

1. Pebrine is caused by a protozoan (Nosema), whereas Flacherie is caused by a virus.

2. In Pebrine, black spots appear on the larval body, and the larva becomes inactive and stops feeding, whereas in Flacherie, the larva turns black, becomes motionless, and hangs downwards.

3. Pebrine spreads through infected larvae, pupae, or moths, whereas Flacherie spreads rapidly in overcrowded and moist conditions.