Question

Zygotic meiosis occurs in
A. Gymnosperms
B. Ferns
C. Moss
D. Algae

Answer 1

Hint:-Alternation of generations is a character of plant life cycles. Haploid and diploid plant bodies are formed during the life cycle of plants. This takes place by both mitotic and meiotic division. In zygotic meiosis, the zygote acts as the meiocyte and meiosis occurs in diploid zygotes. Zygote and sporophyte will be diploid and gametophyte and gametes will be haploid.

Complete Answer:-Algae are the most primitive plant groups which are autotrophic, chlorophyll bearing, and largely aquatic organisms. They reproduce by vegetative, sexual, and asexual modes. Vegetative reproduction takes place by fragmentation while sexual reproduction takes place by the production of zoospores and by the fusion of male and female gametes. The life cycle seen in most of the algae is called the haplontic life cycle. Zygote represents the diploid sporophyte generation. The zygote undergoes meiotic division to form haploid spores and thus zygotic meiosis occurs in most algae. The haploid spores undergo mitosis to form haploid gametophytes. The gametophyte is the free-living, dominant phase in organisms with a haplontic life cycle.
Gymnosperms are higher plants that produce seeds. The female and male gametophytes do not have an independent free-living existence in gymnosperms. The dominant independent phase of the plant is the diploid sporophyte. The haploid gametes are formed by meiosis of the sporophyte. This is a diplontic life cycle.
Mosses are the division of bryophytes which are plants living in soil and require water for their fertilization. Ferns are the sub-division of pteridophytes which include horsetails. Both bryophytes and pteridophytes produce multicellular diploid sporophyte plant bodies that undergo meiosis to form haploid spores. They follow a haplo-diplontic life cycle.

The correct answer is Option D.

Note:- Even though most of the algae have a haplontic life cycle with a dominant free-living gametophyte phase, some genera have diplontic and some others have a haplo-diplontic life cycle. Fucus is a brown alga that follows a diplontic life cycle. Ectocarpus kelps have a haplo-diplontic life cycle. Gametic meiosis occurs in the diploid life cycle. Meiosis occurs only during gamete formation.