CBSE Class 10 - Science - Life processes - Heterotrophic Nutrition - Topic-wise Notes

Overview of Heterotrophic Nutrition

Heterotrophic nutrition varies among organisms based on their specific adaptations to the environment. The method of obtaining nutrition is primarily determined by:

• Type of food material
• Availability of food
• Method of acquisition (how the organism accesses food)

Factors Influencing Nutritive Apparatus

The digestive system or "nutritive apparatus" of an organism evolves based on the nature of its food source.

Food Source Nature	Example	Organism	Implication
Stationary	Grass	Cow	Requires specific apparatus to access/digest stationary plants.
Mobile	Deer	Lion	Requires different apparatus for hunting and consuming moving prey.

Strategies of Food Intake and Digestion

Organisms utilize different strategies to break down and absorb nutrients:

1.  External Digestion (Saprophytic Nutrition)

• Mechanism: The organism breaks down food material outside the body and then absorbs the nutrients.
• Examples: Fungi such as:
• Bread moulds
• Yeast
• Mushrooms

2. Internal Digestion (Holozoic Nutrition)

• Mechanism: The organism takes in (ingests) whole material and breaks it down inside the body.
• Dependencies: The specific type of food taken in depends on the organism's body design and functioning.

3. Parasitic Nutrition

• Mechanism: The organism derives nutrition from other plants or animals (hosts) without killing them.
• Examples:
• Plants: Cuscuta (Amar-bel)
• Insects/Arachnids: Ticks, Lice
• Worms: Leeches, Tape-worms

MCQs: Overview of Heterotrophic Nutrition

1. Heterotrophic nutrition mainly depends on

• A. Size of the organism
• B. Type, availability, and method of acquiring food
• C. Habitat only
• D. Presence of chlorophyll

2. The nutritive apparatus of an organism is influenced by

• A. Climate
• B. Nature of the food source
• C. Age of the organism
• D. Population size

3. A lion has a different digestive and feeding apparatus than a cow because

• A. Lion lives in forests
• B. Cow is domesticated
• C. Lion feeds on mobile prey while cow feeds on stationary plants
• D. Cow eats more food

4. Nutrition in mushroom is characterised by

• A. Internal digestion
• B. External digestion followed by absorption
• C. Feeding on living host
• D. Ingestion of whole food

5. Nutrition in amoeba involves

• A. Absorption of dissolved food
• B. External digestion
• C. Ingestion and internal digestion of food
• D. Feeding without killing host

6. Which of the following pairs is correctly matched?

• A. Saprophytic nutrition — Lion
• B. Parasitic nutrition — Mushroom
• C. Parasitic nutrition — Cuscuta
• D. Holozoic nutrition — Yeast