PG TRB ZOOLOGY ONLINE TEST / QUIZ AS PER LATEST SYLLABUS | Unit I - ANIMAL DIVERSITY AND PHYLOGENY | Origin of mammals.

PG TRB ZOOLOGY ONLINE TEST / QUIZ AS PER LATEST SYLLABUS | Unit I - ANIMAL DIVERSITY AND PHYLOGENY | Origin of mammals.

1. The group of 'mammal-like reptiles' from which mammals are believed to have evolved is known as:

a) Anapsids b) Diapsids c) Synapsids d) Euryapsids

2. Which of the following is considered the most immediate ancestor group of mammals?

a) Therapsids b) Pelycosaurs c) Plesiosaurs d) Thecodonts

3. The presence of a single temporal fenestra on each side of the skull is a key characteristic of which group?

a) Diapsids b) Anapsids c) Euryapsids d) Synapsids

4. Which of the following is a key feature in the transition from Therapsids to mammals?

a) Development of a three-chambered heart b) Formation of a secondary palate c) Loss of heterodont dentition d) Fusion of the quadrate and articular bones

5. The three middle ear ossicles (malleus, incus, stapes) in mammals evolved from which bones in their reptilian ancestors?

a) Quadrate and articular bones b) Dentary and surangular bones c) Quadrate and surangular bones d) Articular and surangular bones

6. The earliest true mammals appeared during which geological period?

a) Triassic period b) Cretaceous period c) Jurassic period d) Permian period

7. The single bone in the lower jaw of mammals is the:

a) Quadrate b) Articular c) Surangular d) Dentary

8. Which of the following is not a characteristic of Therapsids, but is a key feature of true mammals?

a) Heterodont dentition b) Endothermy c) True hair d) A single temporal fenestra

9. The earliest mammals were primarily:

a) Large herbivores b) Small, nocturnal insectivores c) Large predators d) Aquatic filter feeders

10. The dental condition where teeth are replaced only once in a lifetime (milk teeth followed by permanent teeth) is known as:

a) Homodont b) Polyphyodont c) Diphyodont d) Thecodont

11. The origin of mammals is characterized by the change from a jaw joint between the articular and quadrate bones to a joint between the:

a) Dentary and quadrate b) Dentary and squamosal c) Articular and surangular d) Dentary and premaxilla

12. Which of the following reptilian groups is considered a key intermediate in the evolution of Therapsids from Pelycosaurs?

a) Dimetrodon b) Ophiacodon c) Edaphosaurus d) Cynodonts

13. The transition to a more erect posture with limbs positioned underneath the body is a trend seen in the evolution towards mammals. This primarily aids in:

a) Faster running b) Increased camouflage c) Digging burrows d) Flight adaptation

14. Which group of Therapsids is known for having a high level of mammalian features, including a secondary palate and heterodont dentition?

a) Gorgonopsians b) Anomodonts c) Cynodonts d) Dinocephalians

15. The discovery of fossils like _Morganucodon_ and _Hadrocodium_ provides important evidence for the origin of which mammalian feature?

a) The single lower jawbone b) The three middle ear ossicles c) Endothermy d) Mammary glands

16. The Mesozoic Era is often referred to as the 'Age of Reptiles.' During this time, mammals:

a) Were extinct b) Were diverse and dominated large ecological niches c) Were small and inconspicuous d) Were exclusively aquatic

17. The evolution of a secondary palate in mammal ancestors was important because it allowed them to:

a) Breathe while chewing food b) Develop a more powerful bite c) Develop a larger brain case d) Regulate body temperature more effectively

18. The _pelycosaurs_, an early group of synapsids, are well-known for their prominent dorsal sails. A famous example is:

a) Velociraptor b) Tyrannosaurus c) Dimetrodon d) Stegosaurus

19. Which of the following is an early, highly successful group of mammals that went extinct and are known for their rodent-like incisors?

a) Monotremes b) Multituberculates c) Marsupials d) Placentals

20. The development of an improved chewing mechanism in Therapsids, with complex cusps on the cheek teeth, is a key evolutionary step known as:

a) Occlusion b) Mastication c) Heterodonty d) Polyphyodonty

21. What is the name of the subclass of mammals that lay eggs?

a) Theria b) Prototheria c) Metatheria d) Eutheria

22. The characteristic of having hair and mammary glands is thought to be an adaptation for:

a) Aquatic life b) Nocturnal lifestyle c) Herbivorous diet d) Arboreal existence

23. The transition to a more powerful jaw with a larger dentary bone is a key feature of:

a) Early fish b) Amphibians c) Synapsids d) Birds

24. What is the defining characteristic of a mammal’s circulatory system compared to its reptilian ancestors?

a) Presence of a three-chambered heart b) A complete double circulation system c) A single aortic arch d) A heart with a single ventricle

25. The shift from an ectothermic to an endothermic metabolism in the lineage leading to mammals is supported by which fossil evidence?

a) Larger bone size b) A sprawling limb posture c) Highly vascularized bones and turbinates d) The presence of scales

26. Mammals are distinguished from reptiles by the presence of:

a) Jaws b) Lungs c) A single dentary bone d) A heart with four chambers

27. Which of these evolutionary changes is NOT directly related to the improvement of hearing in early mammals?

a) Migration of the articular and quadrate bones b) Formation of the malleus and incus c) A single dentary bone d) Development of the pinna (outer ear)

28. The earliest mammals are believed to have lived alongside dinosaurs during the:

a) Paleozoic Era b) Cenozoic Era c) Mesozoic Era d) Precambrian Era

29. The fossil record indicates that the transition from Therapsid reptiles to true mammals was a:

a) Sudden, rapid event b) Gradual, mosaic process over millions of years c) Process that occurred simultaneously in all continents d) Single-gene mutation event

30. A key feature of mammalian skulls is the occipital condyles, which articulate with the first vertebra. In reptiles, there is typically:

a) No occipital condyle b) One occipital condyle c) Two occipital condyles d) A single, fused occipital condyle

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