Consider the following kinds of organisms:

  1. Copepods
  2. Cyanobacteria
  3. Diatoms
  4. Foraminifera

Which of the above are primary producers in the food chains of oceans?

[UPSC Civil Services Exam – 2021 Prelims]

(a) 1 and 2 only

(b) 2 and 3 only

(c) 3 and 4 only

(d) 1 and 4 only


Answer: (b)        

Explanation:

Copepods:

  • These are any member of the widely distributed crustacean subclass Copepoda.
  • Free-living copepods form a crucial link in the food chain and are often assigned the role of “primary consumers”. Hence statement 1 is incorrect.
  • Copepods are of great ecological importance, providing food for many species of fish.

Cyanobacteria:

  • Cyanobacteria, also called blue-green algae, are microscopic organisms found naturally in all types of water.
  • These single-celled organisms live in fresh, brackish (combined salt and fresh water), and marine water.
  • These organisms use sunlight to make their own food. Hence statement 2 is correct.

Diatoms:

  • Diatoms are photosynthesizing algae, they have a siliceous skeleton (frustule) and are found in almost every aquatic environment including fresh and marine waters, soils, in fact almost anywhere moist. Hence statement 3 is correct.
  • They are non-motile, or capable of only limited movement along a substrate by secretion of mucilaginous material along a slit-like groove or channel called a raphe.
  • Being autotrophic they are restricted to the photic zone (water depths down to about 200m depending on clarity).

Foraminifera:

  • These are any unicellular organism of the rhizopodan order Foraminiferida (formerly Foraminifera), characterized by long, fine pseudopodia that extend from a uninucleated or multinucleated cytoplasmic body encased within a test, or shell.
  • Foraminifera are found in all marine environments, they may be planktic or benthic in their mode of life.
  • Foraminifera are recorded as feeding chiefly upon bacteria, small diatoms, and nannoplankton in a wide variety of marine environments. Hence statement 4 is incorrect.

Consider the following statements:                                                                   The Parliament of India can place a particular law in the Ninth Schedule of the Constitution of India. The validity of a law placed in the Ninth Schedule cannot be examined by any court and no judgement can be made on it. Which of the statements given above is/are correct?

Consider the following statements:                                               

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Consider the following statements:                                                         The Parliament of India can place a particular law in the Ninth Schedule of the Constitution of India. The validity of a law placed in the Ninth Schedule cannot be examined by any court and no judgement can be made on it. Which of the statements given above is/are correct?

Consider the following statements:                                               

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