PG TRB ZOOLOGY | Unit I - ANIMAL DIVERSITY AND PHYLOGENY | Structure, affinities and life history of Minor Phyla – Onychophora

PG TRB ZOOLOGY ONLINE TEST / QUIZ AS PER LATEST SYLLABUS | Unit I - ANIMAL DIVERSITY AND PHYLOGENY | Structure, affinities and life history of Minor Phyla – Onychophora.

1. The common name for the members of Phylum Onychophora is:

a) Sea cucumbers b) Velvet worms c) Spiny-headed worms d) Arrow worms

2. Onychophora are considered a connecting link between which two phyla?

a) Annelida and Arthropoda b) Mollusca and Annelida c) Echinodermata and Chordata d) Platyhelminthes and Nematoda

3. The respiratory organs of Onychophora are:

a) Gills b) Lungs c) Skin d) Tracheae

4. Which of the following is a characteristic feature of Onychophora's body wall?

a) Presence of a hard exoskeleton b) A thin, flexible cuticle with sensory papillae c) Absence of any cuticle d) Segmented plates called sclerites

5. The excretory organs in Onychophora are:

a) Malpighian tubules b) Green glands c) Segmentally arranged nephridia d) Protonephridia

6. Onychophora are known for their unique defense mechanism, which involves:

a) Ejecting a sticky slime from oral papillae b) Stinging with specialized tentacles c) Releasing a foul-smelling liquid d) Autotomy (self-amputation)

7. The muscular, unjointed appendages of Onychophora are called:

a) Parapodia b) Setigerous pads c) Lobopods d) Pseudopods

8. The eyes of Onychophora are typically:

a) Compound eyes b) Paired ocelli, similar to insects c) Highly developed, similar to cephalopods d) Simple, un-compound eyes at the base of the antennae

9. Which of the following is true regarding the circulatory system of Onychophora?

a) It is open with a dorsal tubular heart b) It is a closed system with a ventral heart c) There is no heart; circulation is by diffusion d) It has a heart with four chambers

10. The first pair of modified appendages in Onychophora, used for grasping prey, are the:

a) Oral papillae b) Jaws or mandibles c) Antennae d) Slime glands

11. A key similarity between Onychophora and Annelida is the presence of:

a) Segmentally arranged nephridia b) A chitinous exoskeleton c) Compound eyes d) Tracheal respiration

12. The presence of a dorsal heart, haemocoel, and tracheal system shows the affinity of Onychophora with which phylum?

a) Mollusca b) Arthropoda c) Annelida d) Chordata

13. The coelom in Onychophora is:

a) Large and well-developed b) Entirely absent c) Reduced and replaced by a haemocoel d) A true coelom, but unsegmented

14. The slime glands, used for defense and trapping prey, are modifications of which glands?

a) Salivary glands b) Excretory glands c) Reproductive glands d) Digestive glands

15. In Onychophora, the gas exchange openings are called:

a) Spiracles b) Stomata c) Spiracles (tracheae opening) distributed over the body surface d) Ostia

16. The nervous system of Onychophora consists of a brain and a pair of ventral nerve cords that are:

a) Fused into a single cord b) Widely separated and run parallel c) Completely absent d) Segmentally ganglionated

17. Onychophora are mostly found in which type of habitat?

a) Tropical and temperate forests, in moist places b) Marine environments c) Desert regions d) Freshwater lakes and rivers

18. The life history of Onychophora is characterized by:

a) External fertilization b) Metamorphosis c) Larval stages d) Internal fertilization and viviparity

19. Which genus is a well-known example of Onychophora?

a) Hirudo b) Sepia c) Peripatus d) Asterias

20. The name "Onychophora" literally means:

a) Joint-legged b) Claw-bearers c) Slime-throwers d) Segmented bodies

21. The ventral appendages of Onychophora are thought to be homologous to the parapodia of:

a) Polychaetes b) Oligochaetes c) Hirudinea d) Gastropods

22. Unlike Annelida, Onychophora lack a true:

a) Cuticle b) Nervous system c) Reproductive system d) Peristomium

23. The antennae of Onychophora are derived from which body segment?

a) First segment b) Second segment c) Third segment d) Last segment

24. What is the primary function of the slime secreted by Onychophora?

a) Locomotion b) Reproduction c) Capturing prey d) Digestion

25. The phylum Onychophora is often placed in which superphylum?

a) Lophotrochozoa b) Deuterostomia c) Radiata d) Panarthropoda

26. Which of the following is a feature shared by both Onychophora and Arthropoda?

a) Closed circulatory system b) Chitinous claws on appendages c) Parapodia for locomotion d) External fertilization

27. The heart in Onychophora is situated in the:

a) Pericardial sinus b) Perineural sinus c) Perivisceral sinus d) Cephalic sinus

28. The slime is secreted by glands located on the:

a) Antennae b) Jaws c) Lobopods d) Oral papillae

29. The young ones of Onychophora are hatched directly from the mother's body, a process known as:

a) Oviparity b) Viviparity c) Ovoviviparity d) Parthenogenesis

30. Onychophora are often described as "living fossils" because they have retained a mix of characteristics from:

a) Amphibians and reptiles b) Fish and amphibians c) Annelids and arthropods d) Sponges and coelenterates

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