PG TRB ZOOLOGY | Unit I - ANIMAL DIVERSITY AND PHYLOGENY | Polymorphism and Metagenesis in Coelentrates.

PG TRB ZOOLOGY ONLINE TEST / QUIZ AS PER LATEST SYLLABUS | Unit I - ANIMAL DIVERSITY AND PHYLOGENY | Polymorphism and Metagenesis in Coelentrates.

1. Which of the following coelenterates exhibits trimorphism, with gastrozooids, dactylozooids, and gonozooids?

• Velella
• Physalia
• Porpita
• Obelia

2. The phenomenon of alternation of generations between the asexual polyp and sexual medusa is known as:

• Polymorphism
• Metamorphosis
• Metagenesis
• Neoteny

3. In the life cycle of Obelia, the medusa is produced from the gonozooid by the process of:

• Budding
• Strobilation
• Regeneration
• Binary fission

4. The stinging or defensive zooids in a polymorphic colony of a siphonophore are called:

• Gastrozooids
• Dactylozooids
• Gonozooids
• Spirozooids

5. What is the floating bladder found in Physalia, which helps it to drift on the water surface, called?

• Hydranth
• Pneumatophore
• Gonozooid
• Blastostyle

6. The asexual polypoid form in Obelia is the:

• Medusa
• Hydranth
• Gonangium
• Planula larva

7. In polymorphism, the different individuals of a colony are structurally and functionally different, and are known as:

• Gametocytes
• Zooids
• Somatic cells
• Buds

8. The nutritive zooids responsible for feeding the colony in a siphonophore are:

• Gonozooids
• Phyllozooids
• Dactylozooids
• Gastrozooids

9. Which of the following is an example of a dimorphic coelenterate?

• Hydra
• Physalia
• Obelia
• Aurelia

10. The asexual reproductive structures in a gonangium of Obelia, which give rise to medusae, are known as:

• Hydranths
• Gastrozooids
• Blastostyles
• Medusoids

11. In metagenesis, the polyp reproduces asexually to produce:

• Zygote
• Medusa
• Planula
• Hydranth

12. The reproductive zooids in a coelenterate colony are typically called:

• Gastrozooids
• Nematophores
• Dactylozooids
• Gonozooids

13. Which of the following statements about polymorphism in Coelenterates is correct?

• All zooids in a colony have the same function.
• It is a characteristic of solitary coelenterates.
• It involves division of labour among the zooids.
• It is an example of sexual reproduction.

14. The sexual medusa stage in the life cycle of Obelia is characterized by:

• A sedentary, polypoid form
• Reproduction by budding
• Free-swimming, umbrella-shaped body
• Formation of a perisarc

15. The presence of both polyp and medusa forms in the life cycle of a coelenterate is an example of:

• Dimorphism
• Trimorphism
• Metagenesis
• Polymorphism

16. The polyp of Obelia is typically protected by a chitinous exoskeleton called the:

• Perisarc
• Coenosarc
• Hydrorhiza
• Hydrotheca

17. In the life cycle of Aurelia, the planula larva attaches to a substratum and develops into the:

• Ephyra
• Scyphistoma
• Medusa
• Strobila

18. The gonozooid of Obelia is also known as:

• Hydranth
• Gonangium
• Blastostyle
• Medusa bud

19. Which of the following is not a type of zooid found in a typical siphonophore colony?

• Gastrozooid
• Statocyst
• Gonozooid
• Pneumatophore

20. Metagenesis is primarily observed in which class of Cnidaria?

• Hydrozoa
• Scyphozoa
• Anthozoa
• Cubozoa

21. The larval stage in the life cycle of Obelia is called:

• Ephyra larva
• Planula larva
• Tornaria larva
• Bipinnaria larva

22. Which of the following is an example of a siphonophore?

• Hydra
• Obelia
• Sea Anemone
• Physalia

23. The function of the gonozooid in a polymorphic colony is:

• Digestion
• Defense
• Reproduction
• Locomotion

24. The stalk-like structure in the gonangium of Obelia, which produces medusae, is the:

• Coenosarc
• Hydranth
• Blastostyle
• Perisarc

25. Metagenesis is a life cycle pattern where the asexual phase is ______ and the sexual phase is ______.

• Polyp, Medusa
• Medusa, Polyp
• Planula, Ephyra
• Scyphistoma, Strobila

26. In the life cycle of Aurelia, the strobilation process leads to the formation of:

• Medusae
• Polyps
• Planulae
• Ephyrae

27. Which of the following is not a part of the siphonophore colony?

• Nectophores
• Pneumatophores
• Cormidia
• Acontia

28. The free-swimming medusae of Obelia are produced from the gonangia by:

• Mitosis
• Meiosis
• Budding
• Fragmentation

29. What is the primary role of the polyp stage in the life cycle of Obelia?

• Sexual reproduction
• Dispersal
• Feeding and asexual reproduction
• Gamete formation

30. The medusa of a coelenterate is a free-swimming form, typically responsible for:

• Asexual budding
• Digestion
• Sexual reproduction
• Protection

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