Which among the following life cycle is exhibited by Polysiphonia?a)Diplonticb)Haplonticc)Triplolnticd)Haplo-diplonticCorrect answer is option 'B'. Can you explain this answer?

Question

Answer

Most of the algae are haplontic whereas few others are diplontic. But some algae like Polysiphonia and Ectocarpus and kelps show haplodiplontic
type of life cycle. In haplodiplontic life cycle, the dominant phase may vary viz. a dominant haploid gametophyte will have short-lived multicellular sporophyte while a dominant diploid sporophyte will have short-lived gametophyte.

Answer

Correct ans is D. haplo diplontic.. it is an exception to the haplontic life cycle of algae. it is also given in ncert textbook. U can surely refer to the book.

Answer

Life Cycle of Polysiphonia:
Polysiphonia is a genus of red algae commonly found in marine environments. It exhibits a haplontic life cycle, which is the correct answer.

Haplontic Life Cycle:
A haplontic life cycle is a type of life cycle in which the organism spends the majority of its life cycle in the haploid phase. In this life cycle, the haploid gametes fuse during fertilization to form a diploid zygote, which undergoes meiosis to produce haploid spores. These spores then grow into new haploid individuals, completing the life cycle.

Explanation:
Here is a detailed explanation of the haplontic life cycle exhibited by Polysiphonia:

1. Haploid Gametophyte:
The life cycle of Polysiphonia begins with the haploid gametophyte phase. The gametophyte is the dominant phase in this life cycle. It is a multicellular, haploid organism that produces haploid gametes through mitosis.

2. Gametogenesis:
Within the gametophyte, specialized structures called conceptacles develop. These conceptacles contain reproductive structures known as gametangia. The male gametangia, called antheridia, produce numerous flagellated sperm cells. The female gametangia, called carpogonia, produce eggs.

3. Fertilization:
The sperm cells are released into the surrounding water and are transported to the carpogonia by water currents. Fertilization occurs when a sperm cell fuses with an egg cell, forming a diploid zygote.

4. Diploid Phase:
The zygote develops into a diploid sporophyte, which is a filamentous structure. The sporophyte grows and undergoes meiosis, producing haploid spores.

5. Dispersal and Germination:
The haploid spores are released from the sporophyte and are dispersed by water currents. When conditions are favorable, the spores germinate and develop into new haploid gametophytes, completing the life cycle.

Conclusion:
In conclusion, Polysiphonia exhibits a haplontic life cycle. It begins with the haploid gametophyte phase, where male and female gametes are produced. Fertilization between the gametes results in the formation of a diploid zygote, which grows into a diploid sporophyte. The sporophyte undergoes meiosis to produce haploid spores, which develop into new haploid gametophytes, completing the life cycle.

Top Courses for NEETView all

Biology Class 11

Daily Test for NEET Preparation

NEET Mock Test Series 2025

Topic-wise MCQ Tests for NEET

Physics Class 11

Top Courses for NEET

Top Courses for NEET

Suggested Free Tests

Related Content

About NEET

NEET Preparation Material

How to Prepare for NEET Exam?

NCERT Based Study Material

NEET Mock Tests

Other Popular Exams

Company