NCERT Textbook Exercises
(a) The hairy skin (fleece) of the black sheep has wool.
(b) White fleece means the white coloured hair of the lamb.
(iii) both (a) and (b)
(iv) Woolly dog (Yak, Camel, and Goat yield wool).
(i) Rearing: Raising and taking care of animals (feeding, breeding, medical care) for useful products (like wool/milk).
(ii) Shearing: The process of removing the fleece of the sheep along with a thin layer of skin.
(iii) Sericulture: The rearing of silkworms for obtaining silk.
Shearing, Scouring, Sorting, Cleaning of burrs, Dyeing, Rolling.
The two stages are:
- Caterpillar (Silkworm): It produces silk fibre.
- Pupa (inside Cocoon): The stage where the caterpillar covers itself in silk.
Sericulture and Moriculture.
(Note: Moriculture refers to the cultivation of mulberry plants, which silkworms feed on.)
| Column I | Column II |
|---|---|
| Scouring | Cleaning sheared skin |
| Mulberry leaves | Food of silkworm |
| Yak | Wool yielding animal |
| Cocoon | Yields silk fibres |
Extra Important Questions
The small fluffy fibres that are picked out from the hair (fleece) of sheep are called Burrs. They are similar to the burrs that sometimes appear on our sweaters.
Shearing does not hurt the sheep because the uppermost layer of the skin is dead. Also, the hair of sheep grows back just as our hair does.
Detailed Chapter Topics
- Source: Sheep, Goat, Yak and some other animals. These animals contain a thick coat of hair (fleece) which traps air and keeps them warm.
- Selective Breeding: Process of selecting parents for obtaining special characters in their offspring (e.g. soft under hair in sheep).
- Varieties: Angora wool (Angora goats), Pashmina (Kashmiri goats), Yak wool (Tibet/Ladakh), Llama & Alpaca (South America).
- Shearing: Removal of fleece along with a thin layer of skin. Done in summer.
- Scouring: Washing sheared skin in tanks to remove grease, dust and dirt.
- Sorting: Hairs of different textures are separated.
- Cleaning of Burrs: Small fluffy fibres (burrs) are picked out.
- Dyeing: Fibres are dyed in various colours.
- Rolling: Fibres are straightened, combed and rolled into yarn.
- Source: Silkworms (larvae of silk moth).
- Steps: Female moth lays eggs -> Caterpillars hatch and eat mulberry leaves -> They spin exposure to air hardens protein into silk fibre -> Caterpillar covers itself completely (Cocoon) -> Inside proper development to moth happens -> Cocoons are boiled to separate silk threads -> Reeling the silk.
People working in wool industry (sorters) can get infected by a bacterium called **Anthrax**, which causes a fatal blood disease called **Sorter's disease**.
Key Facts and Definitions
- Sericulture: Rearing of silkworms for silk.
- Shearing: Shaving off the wool coat of sheep.
- Scouring: Washing the sheared wool.
- Reeling: Taking out threads from the cocoon.
- Cocoon: Protective covering spun by silkworm.
- Silk fibre is made of **Protein**.
- Burning silk smells like burning hair (as both are animal proteins).
- Burning paper/cotton smells like burning leaves (as both are plant cellulose).
- India produces varieties of silk: Tassar, Mooga, Kosa, Mulberry.