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