Match Column-I with Column-II and select the correct answer using the codes given below :
Column - I - Column-II
(A) Haplontic life cycle - (i) Fucus
(B) Diplontic life cycle - (ii) Polysiphonia
(C) Diplohaplontic life cycle - (iii) Chlamydomonas
(D) Triphasic life cycle - (iv) Ectocarpus

Question

Match Column-I with Column-II and select the correct answer using the codes given below : 
Column - I - Column-II
(A) Haplontic life cycle -  (i) Fucus
(B) Diplontic life cycle -  (ii) Polysiphonia
(C) Diplohaplontic life cycle - (iii) Chlamydomonas
(D) Triphasic life cycle - (iv) Ectocarpus

Accepted Answer

The correct option is 1: (A)-(iii), (B)-(i), (C)-(iv), (D)-(ii)

The correct pairing is based on the dominant ploidy level and the number of distinct, multicellular phases in the organism's life cycle. This classification is a fundamental concept in the study of algae and plant life cycles. The **Haplontic life cycle** (A) is characterized by a dominant, multicellular haploid (n) stage (gametophyte). The only diploid (2n) structure is the zygote, which immediately undergoes meiotic division to restore the haploid phase. This is perfectly exemplified by **Chlamydomonas** (iii), where the vegetative body is haploid. The **Diplontic life cycle** (B) is the reverse: the dominant, multicellular phase is diploid (sporophyte), and the only haploid stage is the gamete, which fuses immediately after meiosis. This cycle is observed in organisms like **Fucus** (i) and animals. The **Diplohaplontic life cycle** (C), also known as the haplo-diplontic cycle or alternation of generations, involves both a distinct, multicellular haploid gametophyte and a distinct, multicellular diploid sporophyte. **Ectocarpus** (iv) is a classic example that shows an isomorphic alternation, meaning the haploid and diploid phases are structurally similar. Finally, the **Triphasic life cycle** (D) is a unique variation primarily found in the red algae (Rhodophyceae), such as **Polysiphonia** (ii). It involves three phases: a haploid gametophyte, a diploid carposporophyte (which develops on the gametophyte), and a diploid tetrasporophyte, resulting in two diploid phases alternating with one haploid phase.

The incorrect option is 2: (A)-(i), (B)-(iv), (C)-(ii), (D)-(iii)

This option incorrectly matches the life cycles. Pairing the Haplontic life cycle (A) with *Fucus* (i) is wrong because *Fucus* exhibits a Diplontic life cycle where the main plant body is diploid. Similarly, matching the Diplontic life cycle (B) with *Ectocarpus* (iv) is incorrect, as *Ectocarpus* demonstrates a Diplohaplontic life cycle with distinct multicellular haploid and diploid generations. The association of the Diplohaplontic life cycle (C) with *Polysiphonia* (ii) is inaccurate, as *Polysiphonia* is known for its more complex Triphasic life cycle. Finally, placing the Triphasic life cycle (D) with *Chlamydomonas* (iii) is wrong, as *Chlamydomonas* has the simplest Haplontic life cycle.

The incorrect option is 3: (A)-(iv), (B)-(ii), (C)-(iii), (D)-(i)

This combination also contains multiple fundamental errors. Matching the Haplontic life cycle (A) with *Ectocarpus* (iv) is incorrect because *Ectocarpus* has both multicellular haploid and diploid stages, classifying it as Diplohaplontic. The Diplontic life cycle (B) cannot be paired with *Polysiphonia* (ii), which has a characteristic Triphasic life cycle involving three generations. Furthermore, the Diplohaplontic life cycle (C) is mistakenly matched with *Chlamydomonas* (iii), which is the standard example of a Haplontic life cycle. Lastly, pairing the Triphasic life cycle (D) with *Fucus* (i) is a mistake, as *Fucus* is a classic example of a Diplontic organism.

The incorrect option is 4: (A)-(ii), (B)-(iii), (C)-(i), (D)-(iv)

This option is incorrect because none of the pairings are accurate. The Haplontic life cycle (A) is wrongly linked to *Polysiphonia* (ii), a red alga with a Triphasic cycle, indicating a significant misunderstanding of the group's complexity. The Diplontic life cycle (B) is incorrectly matched with *Chlamydomonas* (iii), which is an organism with a dominant haploid phase. The Diplohaplontic life cycle (C) is mistakenly associated with *Fucus* (i), which lacks a multicellular haploid stage and is therefore Diplontic. Finally, the Triphasic life cycle (D) is wrongly assigned to *Ectocarpus* (iv), which only exhibits a Diplohaplontic (or biphasic) alternation of generations.