🌿 Grade 9 Science · Biology

Samacheer Class 9 Science - Economic Biology

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Textbook Exercises
11 Sections
28 Questions

Complete Grade 9 Science questions and answers for Economic Biology. Click any question to expand the answer.

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📋 Sections in this chapter
I. Choose the Correct AnswerII. Fill in the BlanksIII. State Whether True or FalseIV. Match the FollowingV. Differentiate the FollowingVI. Answer BrieflyVII. Answer in DetailVIII. Higher Order Thinking SkillsIntext ActivitiesActivity – 1Activity – 2
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1I. Choose the Correct Answer10 questions

Q.1Production and management of fish is called
✓ Answer
  • (a) Pisciculture
  • (b) Sericulture
  • (c) Aquaculture
  • (d) Monoculture

Answer:
(a) Pisciculture


Q.2Which is not an exotic breed of cattle?
✓ Answer
  • (a) Jersey
  • (b) Holstein–Friesian
  • (c) Sahiwal
  • (d) Brown Swiss

Answer:
(c) Sahiwal


Q.3Italian species of honey bee is
✓ Answer
  • (a) *Apis mellifera*
  • (b) *Apis dorsata*
  • (c) *Apis florea*
  • (d) *Apis cerana*

Answer:
(a) *Apis mellifera*


Q.4Which is not an Indian major carp?
✓ Answer
  • (a) Rohu
  • (b) Catla
  • (c) Mrigal
  • (d) Singhara

Answer:
(d) Singhara


Q.5Drones in honey bee colony develop from
✓ Answer
  • (a) unfertilized eggs
  • (b) fertilized eggs
  • (c) parthenogenesis
  • (d) both (b) and (c)

Answer:
(a) unfertilized eggs

Drones are produced by parthenogenesis.

Q.6High milk-yielding cattle breed is
✓ Answer
  • (a) Holstein–Friesian
  • (b) Dorset
  • (c) Sahiwal
  • (d) Red Sindhi

Answer:
(a) Holstein–Friesian


Q.7Indian honey bee commonly used in apiculture
✓ Answer
  • (a) *Apis dorsata*
  • (b) *Apis florea*
  • (c) *Apis mellifera*
  • (d) *Apis indica*

Answer:
(d) *Apis indica*


Q.8Growing plants without soil is called
✓ Answer
  • (a) Horticulture
  • (b) Hydroponics
  • (c) Pomology
  • (d) None of these

Answer:
(b) Hydroponics


Q.9Symbiotic association between fungi and plant roots is
✓ Answer
  • (a) Lichen
  • (b) Rhizobium
  • (c) Mycorrhiza
  • (d) Azotobacter

Answer:
(c) Mycorrhiza


Q.10Vegetative body of mushroom is
✓ Answer
  • (a) Spawn
  • (b) Mycelium
  • (c) Leaf
  • (d) All of these

Answer:
(b) Mycelium



2II. Fill in the Blanks0 questions
  • Quinine is obtained from Cinchona.
  • *Carica papaya* leaves are used in dengue treatment support.
  • Vermicompost is produced using earthworms and microorganisms.
  • Aquaculture includes culture of prawns, pearls and edible oysters.
  • Largest member in honey bee colony is the queen bee.
  • Formic acid acts as preservative in honey.
  • Polyculture means rearing different fish varieties together.


3III. State Whether True or False5 questions

If false, correct the statement.


Q.1Mycorrhiza is an algae.
✓ Answer

Answer: False. Correct Statement: Mycorrhiza is not an algae but rather a symbiotic association between a fungus and plant roots. In this mutualistic relationship, the fungal hyphae penetrate the root cells or surround the roots, extending the absorptive surface area and helping the plant absorb water and mineral nutrients, particularly phosphorus, from the soil. In return, the plant provides carbohydrates and organic compounds produced through photosynthesis to the fungus. This association is beneficial for both organisms and is commonly found in most terrestrial plants.

Q.2Milch animals are used in agriculture and transport.
✓ Answer

Answer: False. Correct Statement: Milch animals are primarily reared for milk production, not for agriculture and transport. Milch animals such as cows, buffalo, and goats are dairy animals specifically bred and maintained to produce milk and milk products like yogurt, cheese, and butter. While some milch animals may occasionally be used for other purposes, their main economic value and purpose is milk production.

Q.3*Apis florea* is rock bee.
✓ Answer

Answer: False. Correct Statement: Apis dorsata is called the rock bee or giant honeybee, not Apis florea. Apis florea is the little honeybee or dwarf honeybee. Apis dorsata is a large wild honeybee species found in Asia that builds large combs on rock cliffs and tree branches, hence the name rock bee. Apis florea, being smaller, builds smaller combs and is found in different habitats.

Q.4Ongole is an exotic cattle breed.
✓ Answer

Answer: False. Correct Statement: Ongole is an indigenous Indian cattle breed, not an exotic breed. Ongole cattle originated in the Ongole region of Andhra Pradesh, India, and are well-adapted to the Indian climate and environmental conditions. They are known for their good milk production, draught capability, and resistance to diseases and heat. Indigenous breeds like Ongole have been developed and selected over generations to suit local conditions, unlike exotic breeds which are introduced from other countries.

Q.5Sheep manure contains more nutrients than farmyard manure.
✓ Answer

Answer: True



4IV. Match the Following0 questions
Column AColumn B
LobstersShell fish
CatlaFin fish
Sea bassMarine fish
OystersPearl
PokkaliPaddy
*Pleurotus* spp.Oyster mushroom
SarpagandhaReserpine
OlericultureVegetable farming
*Wrightia tinctoria*Psoriasis


5V. Differentiate the Following0 questions

# (a) Exotic Breed and Indigenous Breed

Exotic BreedIndigenous Breed
Imported from foreign countriesNative Indian breeds
High milk yieldBetter disease resistance
Examples: Jersey, Brown SwissExamples: Sahiwal, Gir

# (b) Pollen and Nectar

PollenNectar
Powdery male reproductive particlesSweet liquid secretion
Produced by antherProduced by nectaries
Helps fertilizationAttracts pollinators

# (c) Shrimp and Prawn

ShrimpPrawn
Mostly marineFreshwater and marine
Smaller bodyGenerally larger body

# (d) Farmyard Manure and Sheep Manure

Farmyard ManureSheep Manure
Cow dung, urine and litterSheep/goat excreta
Lower nutrient contentHigher nutrient content
Common organic manureRich in nitrogen


6VI. Answer Briefly6 questions

Q.1What are Secondary Metabolites?
✓ Answer

Answer:

Organic compounds produced by organisms that are not directly involved in growth or reproduction are called secondary metabolites.

Examples:

  • Alkaloids
  • Essential oils
  • Antibiotics

Q.2Types of Vegetable Gardens
✓ Answer

Answer:

  • Kitchen garden
  • Commercial garden
  • Vegetable forcing
  • Greenhouse gardening
  • Organic vegetable gardening

Q.3Mushroom Preservation Methods
✓ Answer

Answer:

  • Freezing
  • Drying
  • Canning
  • Vacuum cooling

Q.4Advantages of Vermicompost
✓ Answer

Answer:

  • Eco-friendly
  • Rich in nutrients
  • Improves soil fertility
  • Contains useful microbes
  • Enhances decomposition

Q.5Earthworms Used in Vermiculture
✓ Answer

Answer:

  • *Perionyx excavatus*
  • *Eisenia fetida*
  • *Eudrilus eugeniae*

Q.6Medicinal Importance of Honey
✓ Answer

Answer:

  • Has antibacterial and antiseptic properties.
  • Soothes sore throat and cough.
  • Aids wound healing.
  • Provides quick energy.
  • Helps digestion.
  • Has antioxidant properties.
Honey should not be given to infants below one year of age.


7VII. Answer in Detail5 questions

Q.1Advantages of Hydroponics
✓ Answer

Answer:

Hydroponics is growing plants without soil using nutrient solution.


Advantages

  • Saves water and nutrients
  • Faster plant growth
  • Better yield
  • Suitable for deserts and cold regions
  • Fewer weeds and pests

Q.2Mushroom Cultivation
✓ Answer

# Mushroom Culture

Growing mushrooms using agricultural and industrial wastes.


Steps in Mushroom Cultivation


# (i) Composting

  • Paddy straw mixed with cow dung and fertilizers
  • Maintained around (50^\circ C)

# (ii) Spawning

  • Spawn acts as mushroom seed
  • Fungal mycelium grown under sterile conditions

# (iii) Casing

Thin soil layer added to maintain humidity and temperature.


# (iv) Pinning

Small white buds develop into mushrooms.


# (v) Harvesting

  • Temperature maintained between (15^\circ C) and (23^\circ C)
  • Mushrooms harvested after about 3 weeks

Q.3Sources for Vermicomposting
✓ Answer

Answer:

Biodegradable wastes used include:

  • Crop residues
  • Vegetable wastes
  • Fruit wastes
  • Leaf litter
  • Animal wastes
  • Biogas slurry

Q.4Types of Fish Ponds
✓ Answer

Fish ponds are classified into five main types based on their specific functions in fish farming. Breeding ponds are used for maintaining and breeding mature fishes to obtain fertilized eggs for reproduction. Hatchling ponds are designed specifically for hatching the fertilized eggs under controlled conditions. Nursery ponds are used for rearing young hatchlings, allowing them to grow into fry, which are juvenile fish. Rearing ponds are utilized to raise fry into fingerlings, which are slightly larger juvenile fish. Stocking or culture ponds are the largest ponds where fingerlings are raised to market size, the final stage before fish are harvested for sale. Each pond type maintains specific environmental conditions suited to the developmental stage of the fish being cultured.

Q.5Classification of Cattle Breeds
✓ Answer
TypeExamples
Milch breedsSahiwal, Gir
Draught breedsKangayam, Hallikar
Dual-purpose breedsHariana, Ongole


8VIII. Higher Order Thinking Skills2 questions

Q.1Importance of Biomanuring
✓ Answer

Answer:

  • Reduces pollution
  • Improves soil fertility
  • Eco-friendly farming
  • Enhances crop productivity

Q.2Significance of Hexagonal Honeycomb Cells
✓ Answer

Answer:

Honeycomb is made from wax secreted by worker bees.


Importance of Hexagonal Shape

  • Maximum storage with minimum wax
  • Strong structure
  • Stores honey and pollen
  • Used for rearing larvae


9Intext Activities0 questions


10Activity – 10 questions

Observation of Earthworms in Vermicompost

Observation

Earthworms convert organic waste into nutrient-rich compost.



11Activity – 20 questions

Honey Bee Colony

Bee TypeFunction
Queen beeEgg laying
Worker beeCollect nectar and hive maintenance
DroneReproduction

# Important Summary


Pisciculture

Fish farming.


Apiculture

Honey bee rearing.


Hydroponics

Growing plants without soil.


Vermicomposting

Using earthworms to prepare organic manure.


Mycorrhiza

Association between fungi and plant roots.


Mushroom Mycelium

Vegetative body of fungus.


Polyculture

Growing multiple fish species together.


Honey Bee Types

  • Queen
  • Worker
  • Drone

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