UPSC Prelims 2001 Q127: Science & Technology – Biology
Epiphytes are plants which depend on other plants for
- (a) food
- (b) mechanical support
- (c) shade
- (d) water
Answer: (b) mechanical support
Explanation
What epiphytes depend on other plants for
| Plant type | Dependence on host |
|---|---|
| Epiphyte (orchids, mosses, ferns on trees) | Mechanical support only — makes its own food |
| Parasite (Cuscuta) | Food and water from the host |
| Partial parasite (mistletoe) | Water and minerals; makes its own food |
| Saprophyte (fungi) | Food from dead matter |
Epiphytes grow on other plants only for support and to reach light. They make their own food and take water from rain and humid air, often through special roots (velamen in orchids).
Answer: (b) mechanical support.
Why each option is right or wrong
- (a) Incorrect. Epiphytes make their own food; that would be a parasite.
- (b) CORRECT. Epiphytes use other plants only for support.
- (c) Incorrect. Epiphytes grow on trees to get light, not shade.
- (d) Incorrect. Epiphytes take water from rain and air, not from the host.
Key point
Orchids are classic epiphytes; their velamen roots absorb moisture from the air.
Remember
Epiphyte = support only; parasite = food.
Common mistakes
- Confusing epiphytes with parasites.
- Thinking epiphytes take water from the host tree.
- Thinking they seek shade under the canopy.
Exam tip
Epi = upon: an epiphyte just sits on another plant.
Sources
- NCERT Class XII — Biology, chapter 'Organisms and Populations' (population interactions)
- NCERT Class VII — Science, chapter 'Nutrition in Plants'