
Isomorphic alternation of generation is found in
A) Ulva
B) Spirogyra
C) Sargassum
D) Oedogonium
Answer
476.4k+ views
Hint: Alternation of generations is the alternation of a sexual phase and an asexual phase in the life cycle of an organism. The two phases, or generations, are often morphologically, and sometimes chromosomally, distinct.
Complete answer:
To answer this question first we need to understand what is an isomorphic alternation of generations. In this type of alternation of generation, the sporophyte and gametophyte are morphologically similar or identical; whereas in a heteromorphic alternation of generations they are dissimilar.
1) Ulva comprises sea lettuces. The sea lettuces comprise the genus Ulva, a group of edible green algae that is widely distributed along the coasts of the world's oceans. In ulva the haploid zoospores give rise to the gametophytes. Both kinds of plants are morphologically identical and therefore ulva shows an isomorphic alternation of generations.
2) In Spirogyra, the sexual reproduction involves a cycle alternation between a haploid vegetative filament (gametophyte plant) and a diploid zygospore, towards the end of growing season the Spirogyra filament produce aplanogametes in vegetative cells called gametangia. The gametes fuse to form a zygospore (2n) gametophyte. But they are morphologically different and therefore ulva shows a heteromorphic alternation of generations.
3) The life cycle of Sargassum is a diplontic type and there is no alternation of generation. The gametes only are haploid structures in the life cycle. After fertilization a diploid zygote is formed which divides to make a diploid sporophyte thallus.
4) Oedogonium is a genus of green freshwater, filamentous macroalgae. The filaments set it apart from other types of macroalgae, due to its rings of cells. Like many algae, Oedogonium exhibits a haploid life cycle. And thus, shows no alternation of generation.
Thus, the correct answer is option A (Ulva).
Note:The dominant generation in vascular plants showing alternation of generation is the sporophyte, while in the non-vascular plants is the gametophyte.
Complete answer:
To answer this question first we need to understand what is an isomorphic alternation of generations. In this type of alternation of generation, the sporophyte and gametophyte are morphologically similar or identical; whereas in a heteromorphic alternation of generations they are dissimilar.
1) Ulva comprises sea lettuces. The sea lettuces comprise the genus Ulva, a group of edible green algae that is widely distributed along the coasts of the world's oceans. In ulva the haploid zoospores give rise to the gametophytes. Both kinds of plants are morphologically identical and therefore ulva shows an isomorphic alternation of generations.
2) In Spirogyra, the sexual reproduction involves a cycle alternation between a haploid vegetative filament (gametophyte plant) and a diploid zygospore, towards the end of growing season the Spirogyra filament produce aplanogametes in vegetative cells called gametangia. The gametes fuse to form a zygospore (2n) gametophyte. But they are morphologically different and therefore ulva shows a heteromorphic alternation of generations.
3) The life cycle of Sargassum is a diplontic type and there is no alternation of generation. The gametes only are haploid structures in the life cycle. After fertilization a diploid zygote is formed which divides to make a diploid sporophyte thallus.
4) Oedogonium is a genus of green freshwater, filamentous macroalgae. The filaments set it apart from other types of macroalgae, due to its rings of cells. Like many algae, Oedogonium exhibits a haploid life cycle. And thus, shows no alternation of generation.
Thus, the correct answer is option A (Ulva).
Note:The dominant generation in vascular plants showing alternation of generation is the sporophyte, while in the non-vascular plants is the gametophyte.
Recently Updated Pages
Master Class 11 Accountancy: Engaging Questions & Answers for Success

Express the following as a fraction and simplify a class 7 maths CBSE

The length and width of a rectangle are in ratio of class 7 maths CBSE

The ratio of the income to the expenditure of a family class 7 maths CBSE

How do you write 025 million in scientific notatio class 7 maths CBSE

How do you convert 295 meters per second to kilometers class 7 maths CBSE

Trending doubts
10 examples of friction in our daily life

One Metric ton is equal to kg A 10000 B 1000 C 100 class 11 physics CBSE

Difference Between Prokaryotic Cells and Eukaryotic Cells

State and prove Bernoullis theorem class 11 physics CBSE

What organs are located on the left side of your body class 11 biology CBSE

Write down 5 differences between Ntype and Ptype s class 11 physics CBSE
