Question

Sporic meiosis occurs in
A. Animals
B. Thallophyta
C. Bryophyta
D. All plants except Thallophyta

Answer 1

Sporic meiosis occurs in those organisms who exhibit both haplontic and diplontic phases in their life cycle that is an alternation of generation. Spores are diploid, and when it undergoes meiosis, haploid gametophytes are forms.

Step by step answer: Thallophytes grows mainly in water and other varieties of habitats such as moist stones, soil and wood. These groups of plants do not have specific parts like roots, stems, leaves and flowers because they are simple thalloid organisms that have a thallus-like plant body. They are autotrophic, chlorophyll bearing plants commonly called algae. Algae may be unicellular or multicellular, for example, Chlamydomonas is unicellular cup-shaped algae and Volvox is a multicellular alga. Various types of fungi that do not have chlorophyll are also included in this group, they are also called as thallophytes, for example, yeasts and moulds.
Other members of the plant kingdom like bryophytes, pteridophytes, gymnosperms, and angiosperms, when form diploid zygote, undergo sporic meiosis to form a multicellular sporophyte and then give rise to haploid spores which make new plants. No such thing happens in thallophytes. In thallophytes, the members reproduce by vegetative, asexual and sexual methods. Vegetative reproduction is by fragmentation, asexual reproduction is by spores which on germination give rise to new plants.
Sexual reproduction occurs by fusion of gametes. It is of three types that are isogamous, anisogamous, and oogamous. The reproduction in which gametes look similar is called isogamous. For example, Ulothrix and spirogyra.
The reproduction in which gametes are dissimilar in size are called as anisogamous, for example, eudorina and the reproduction in which there is a fusion of one large female nonmotile gamete and a small motile gamete is called as oogamous, for example, volvox.
Algae are divided into three classes that are Chlorophyceae, Phaeophyceae, and Rhodophyceae. Chlorophyceae are green algae, Phaeophyceae are brown algae and Rhodophyceae are red algae.
Reproduction in fungi takes place by vegetative means like fragmentation, fission, and budding. Asexual reproduction and sexual reproduction occurs by spores which are formed in the fruiting bodies. In plants, haplontic, diplontic and haplo – diplontic, these three types of life cycle patterns occur. Algae follow a haplontic life cycle, gymnosperms and angiosperms follow diplontic life cycle and bryophytes and pteridophytes follow haplo – diplontic life cycle.
Hence option D is correct.

Note: Although algae exhibit haplontic life cycle some algae don’t follow these. Fucus, the brown algae, exhibits a diplontic life cycle. Ectocarpus, polysiphonia, and kelps exhibit haplo – diplontic life cycle.