Question

The dominant part of the life cycle of algae and fungi is:
(A) Haploid
(B) Haplobiontic
(C) Diploid
(D) Both haploid and diploid are equal

Answer 1

Hint: Gametes are produced either by meiosis or mitosis and forms two or four individuals. By meiosis, four gametes are produced and two identical daughters are formed in mitosis. The life cycle of algae and fungi are dominated by the gametophyte stage of the life cycle.

Complete step by step answer: The dominant part of the life cycle of algae and fungi is haploid. In the life cycle of algae and fungus, a haploid phase alternates with a diploid phase. The haploid phase ends with nuclear fusion, and the diploid phase begins with the formation of the zygote (the diploid cell resulting from the fusion of two haploid sex cells). In the majority of algae and fungi, all structures are haploid except the zygote which is diploid. The haploid phase is called the gametophytic phase, whereas the diploid stage in the life cycle is called the sporophytic phase. In the diploid life cycle of fungi and algae, the plant body is sporophyte which develops sex organs. Sex organs produce gametes by meiosis. The gamete only represents the gametophyte stage. The gamete undergoes fertilization immediately and forms a zygote. The zygote does not undergo meiosis and give rise to the new sporophytic plant body. The type of life cycle is found in the majority of the members of Bacillariophyceae and some members of Chlorophyceae like Cladophora glomerata. Fucus and sargassum of Phaeophyceae also show this type of life cycle.
Hence, the correct answer is option A.

Note: Fungi are usually multicellular organisms that are heterotrophic in nature. Some of them show a symbiotic association with other organisms. They possess structures such as hyphae, mycelium, etc. Algae produce oxygen as a by-product in photosynthesis. While fungi are very useful for humans as it helps in yielding of medicines or antibiotics, by maintaining soil fertility, etc.