TRB PG Assistant - Organization of coelom, symmetry and metamerism Online Test (MCQ Quiz)

1. Which term describes the arrangement of organs within a body cavity?

A) Symmetry B) Metamerism C) Coelom organization D) Segmentation

2. What is the primary characteristic of metamerism?

A) Radial arrangement of body parts B) Bilateral symmetry C) Serial repetition of body segments D) Presence of a true coelom

3. An animal that exhibits radial symmetry has body parts arranged around a central axis. Which phylum is a classic example of radially symmetrical animals?

A) Annelida B) Arthropoda C) Cnidaria D) Mollusca

4. Which of the following describes a coelomate animal?

A) Lacks a body cavity entirely B) Has a body cavity between the ectoderm and endoderm, not lined by mesoderm C) Has a body cavity derived from the blastocoel D) Has a body cavity completely lined by mesoderm

5. Animals with bilateral symmetry typically possess which of the following?

A) Multiple planes of symmetry B) A single plane dividing the body into mirror images C) No distinct anterior or posterior end D) Radial arrangement of appendages

6. What is a pseudocoelom?

A) A body cavity completely lined by mesoderm B) A true coelom that has collapsed C) A body cavity not entirely lined by mesoderm, typically between the ectoderm and endoderm D) The absence of any internal body cavity

7. Which phylum is characterized by true metamerism?

A) Platyhelminthes B) Nematoda C) Annelida D) Echinodermata

8. Acoelomate animals, like flatworms, lack which of the following?

A) A digestive tract B) Nervous system C) A true coelom or pseudocoelom D) A defined body shape

9. Which type of symmetry is most advantageous for directed locomotion and cephalization?

A) Radial symmetry B) Bilateral symmetry C) Asymmetry D) Spherical symmetry

10. In metamerism, the body is divided into segments. What is the term for the mesodermal partitions separating these segments?

A) Blastocoel B) Coelom C) Septa D) Epidermis

11. Which of the following is an example of an animal exhibiting pseudocoelom?

A) Earthworm B) Starfish C) Roundworm (Ascaris) D) Jellyfish

12. The presence of a coelom allows for greater complexity in which of the following?

A) Skeletal structure B) Reproductive system C) Organ development and function D) Sensory perception

13. Which phylum exhibits secondary radial symmetry, derived from an ancestral bilateral symmetry?

A) Cnidaria B) Porifera C) Echinodermata D) Mollusca

14. What is the term for an animal that has no symmetry?

A) Symmetrical B) Asymmetrical C) Bilateral D) Radial

15. The segmentation observed in arthropods is considered homologous to that in annelids, indicating a shared evolutionary origin. This type of segmentation is called:

A) Pseudometamerism B) True metamerism C) Superficial segmentation D) Functional segmentation

16. Which of the following is a function of the coelom in many animals?

A) Structural support only B) Primary site of digestion C) Hydrostatic skeleton, transport of materials, and organ protection D) Exclusively for reproduction

17. If an animal can be divided into two identical halves by only one specific plane passing through the midline, it exhibits:

A) Radial symmetry B) Bilateral symmetry C) Asymmetry D) Spherical symmetry

18. The body cavity in acoelomate animals is filled with:

A) Fluid B) Air C) Parenchyma cells D) Hemolymph

19. Which of these phyla contains animals that are typically acoelomate?

A) Annelida B) Nematoda C) Platyhelminthes D) Arthropoda

20. The development of a coelom is considered a significant evolutionary step. Which germ layer gives rise to the coelom?

A) Ectoderm B) Endoderm C) Mesoderm D) Mesoglea

21. Cephalization, the concentration of sensory organs and nerve tissue at the anterior end, is most commonly associated with which type of symmetry?

A) Radial symmetry B) Bilateral symmetry C) Asymmetry D) Spherical symmetry

22. Which of the following best describes the coelom organization in a pseudocoelomate animal?

A) No coelom exists B) Coelom is entirely absent C) Body cavity is between the ectoderm and endoderm, not fully lined by mesoderm D) Body cavity is fully enclosed by mesoderm

23. The repetition of body parts along the anterior-posterior axis in segmented animals is termed:

A) Radial symmetry B) Bilateral symmetry C) Metamerism D) Asymmetry

24. Which of the following is NOT a characteristic of true coelomates?

A) Body cavity lined by mesodermal peritoneum B) Organs suspended within the coelom C) Coelom derived from the blastocoel D) Development of a complex organ system

25. In a radially symmetrical animal, what is the relationship between the oral and aboral surfaces?

A) They are identical B) They are separated by a single plane C) They are opposite ends of the main body axis D) They do not exist

26. Which of the following is an example of an animal exhibiting metamerism?

A) Sponge B) Jellyfish C) Earthworm D) Starfish

27. The term 'schizocoelous' refers to the formation of the coelom by:

A) Splitting of the mesoderm B) Invagination of the endoderm C) Formation from the blastocoel D) Degeneration of the ectoderm

28. Which type of symmetry is found in animals that are typically sessile or free-floating in aquatic environments?

A) Bilateral symmetry B) Asymmetry C) Radial symmetry D) Spherical symmetry

29. What is the primary function of the mesenteries in coelomate animals?

A) Digestion of food B) Suspension and support of internal organs C) Gas exchange D) Waste excretion

30. The body of a tapeworm, while appearing segmented, is actually an example of:

A) True metamerism B) Pseudometamerism (proglottids) C) Bilateral symmetry D) Radial symmetry

31. Which of the following is a characteristic feature of bilateral symmetry?

A) Dorsoventral axis B) Anteroposterior axis C) Both anteroposterior and dorsoventral axes D) Radial arrangement of body parts

32. In enterocoelous coelom formation, the coelom arises from:

A) Splitting of the mesoderm B) Outpocketings of the primitive gut (archenteron) C) The blastocoel D) The ectoderm

33. Which of these phyla exhibits true coelom?

A) Nematoda B) Platyhelminthes C) Annelida D) Cnidaria

34. What is the main advantage of metamerism in terms of locomotion?

A) Allows for more efficient circulation B) Enables specialized muscle action in different segments C) Facilitates respiration D) Aids in sensory reception

35. The body cavity in a roundworm (e.g., Ascaris) is described as:

A) Acoelomate B) Pseudocoelomate C) Coelomate D) Hemocoel

36. Which of the following is an example of an animal with radial symmetry?

A) Frog B) Eagle C) Sea anemone D) Snake

37. The dorsal nerve cord in chordates is an example of centralization, which is often linked to:

A) Radial symmetry B) Asymmetry C) Bilateral symmetry D) Spherical symmetry

38. What distinguishes a true coelom from a pseudocoelom?

A) The presence of mesodermal lining on both sides of the body cavity B) The origin from the blastocoel C) The absence of any internal cavity D) The presence of only ectodermal lining

39. The phenomenon where body segments become specialized for different functions (e.g., head, thorax, abdomen) is known as:

A) Radial differentiation B) Metameric tagmatization C) Bilateral specialization D) Acoelomate adaptation

40. Which phylum exhibits a water vascular system, which is a unique feature related to its coelomic cavity?

A) Annelida B) Mollusca C) Echinodermata D) Arthropoda

41. An animal that can be divided into mirror-image halves along any plane passing through its central axis exhibits:

A) Bilateral symmetry B) Radial symmetry C) Asymmetry D) Biradial symmetry

42. The coelom in annelids serves as a hydrostatic skeleton, allowing for burrowing and locomotion. This is an example of:

A) Acoelomate function B) Pseudocoelomate function C) Coelomate function D) Acellular support

43. Which of the following is a key characteristic of the phylum Platyhelminthes regarding their body cavity?

A) They are coelomate B) They are pseudocoelomate C) They are acoelomate D) They possess a hemocoel

44. The evolutionary trend towards bilateral symmetry is strongly correlated with the development of:

A) A sessile lifestyle B) Active movement and predation C) Radial body plan D) A simple body structure

45. What is the significance of the coelom being lined by peritoneum (a mesodermal layer)?

A) It allows for direct contact with the external environment. B) It supports the development of complex organs and their suspension. C) It is a primitive trait found in all animals. D) It is primarily for structural rigidity.

46. Which of the following is an example of a metamerically segmented animal?

A) Octopus B) Grasshopper C) Jellyfish D) Sponge

47. The term 'bilateral symmetry' implies the existence of:

A) An oral and aboral surface B) An anterior and posterior end, and a dorsal and ventral surface C) No distinct ends or surfaces D) Multiple planes of symmetry

48. In which type of symmetry are the body parts arranged around a central axis, often with a distinct top and bottom, but no left or right sides?

A) Bilateral symmetry B) Asymmetry C) Radial symmetry D) Spherical symmetry

49. The ability to regenerate lost body parts is often more pronounced in animals with:

A) Complex coelomic systems B) Highly specialized organ systems C) Simpler body plans, like acoelomates or radially symmetrical animals D) True metamerism

50. Which of the following is NOT a type of coelom organization?

A) Acoelomate B) Pseudocoelomate C) Coelomate D) Monocoelomate

Organization of coelom, symmetry and metamerism - Online Test

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