Question

Metagenesis is found in
A) Hydra
B) Obelia
C) Aurelia
D) Tubipora

Answer 1

Hint: Metagenesis is defined as alternation of generations between the reproductive phases – sexual and asexual.

Complete Answer:
Let us analyse the options to find the correct answer.

Option A: Hydra is a representative of fresh-water organisms belonging to the Class Hydrozoa. These organisms are natives of both the temperate and tropical regions. Hydra shows only asexual mode of reproduction via budding. As there is no sexual reproduction, metagenesis is not possible in case of Hydra. Therefore, this is the incorrect option.

Option B: Belonging to the Genus Hydrozoans, the Obelia represents a class of marine and freshwater animal species. These species are characterised by their ability to exhibit both the stages of polyp and medusa as a part of their life cycle. As polyp represents the asexual form while the medulla represents the sexual form, it is quite evident that the metagenesis is common in Obelia. Therefore, this is the incorrect option.

Option C: Aurelia or commonly moon jellies is a cluster of 13 different species and is widely distributed across marine environments. No metagenesis is observed in the case of Aurelia. Therefore, this is the incorrect option.

Option D: Tubipora represents soft corals and the only genus to be present in the monotypic family named Tubiporidae. Little to no information is available about Tubipora's mode of reproduction. Therefore, this is the incorrect option.

Thus, the correct option is B) Obelia.

Note: Obelia are abundantly found across the coastal waters of both Atlantic and Pacific oceans. The characteristics of obelia are,
- They are generally sedentary.
- They are cosmopolitan- mostly live in freshwater or marine habitats.
- They are commonly known as sea fur.
- They are white or light brown in colour.
- They have vertical branching stems.