NEET UG · Biology

Biological Classification

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Biological Classification Practice Questions

50 questions — tap any to view the full solution.

1. In the hierarchy of classification, which of the following statements correctly describes the relationship between a Family and an Order? 2. Which of the following statements about viruses is most accurate in explaining why they are considered 'on the border' between living and non-living? 3. A scientist discovers a unicellular organism that is photosynthetic, has a cell wall made of cellulose, and stores food as starch. It does not have specialized tissues. This organism most likely belongs to: 4. Which of the following is a characteristic feature of all prokaryotic cells? 5. The cell wall of fungi is composed of chitin, while that of plants is cellulose. This difference primarily reflects a divergence in: 6. Which of the following is the correct definition of a 'Phylum' in the context of animal classification? 7. What is the primary function of a "key" in taxonomic studies? 8. Consider a classification challenge: an organism has characteristics of both plants (autotrophic, cell wall) and animals (motile, lacks cellulose in cell wall, ingestive nutrition). Which kingdom in Whittaker's system was designed to accommodate such 'borderline' cases? 9. Which of the following groups of organisms contributes significantly to the oxygen content of the atmosphere and forms the base of many aquatic food webs, often called 'chief producers of the oceans'? 10. The most significant contribution of Carl Woese's three-domain system of classification was: 11. A biologist studying microbial diversity discovers a single-celled, eukaryotic organism. It lacks a cell wall, forms amoeboid structures, and engulfs bacteria as food. Under certain conditions, these individual cells aggregate to form a multicellular structure that produces spores. This organism is most likely a: 12. Which of the following features is uniquely characteristic of organisms belonging to Kingdom Fungi and differentiates them from Plantae and Animalia? 13. The earliest attempts at classification, like Aristotle's, were based on very simple criteria. What was the primary limitation of such early classification systems compared to modern ones? 14. Which group of protists is known for having a protein-rich layer called a pellicle instead of a cell wall, and possesses two flagella, one short and one long? 15. A scientist discovers a new prokaryotic organism. It lives in the absence of oxygen and generates ATP by metabolizing organic compounds without an external electron acceptor. Its cell membrane contains branched-chain lipids. This organism is most likely a: 16. Which of the following taxonomic aids is a storehouse of collected plant specimens that are dried, pressed, and preserved on sheets, providing a quick reference system in taxonomic studies? 17. Assertion (A): Chemoautotrophic bacteria play a crucial role in nutrient recycling. Reason (R): They oxidize various inorganic substances like nitrates, nitrites, and ammonia to release energy for ATP production. 18. Which of the following is NOT a characteristic feature of all members of the Kingdom Fungi? 19. The statement "artificial classification systems are often based on a few easily observable morphological characters" is best exemplified by: 20. Which of the following is a characteristic feature that distinguishes red algae (Rhodophyta) from most other algal groups? 21. A scientist collects an organism from a pond. It is unicellular, eukaryotic, has no cell wall, and moves using cilia. It has a distinctive macronucleus and micronucleus. This organism is most likely a: 22. In the context of bacterial classification, the presence of methanogens in the gut of ruminant animals and marshy areas highlights their ecological role. These organisms belong to: 23. The term "biological species concept" primarily emphasizes which of the following criteria for defining a species? 24. Which of the following describes a key difference in the genetic material organization between a typical bacterium and an archaebacterium? 25. A taxonomist is classifying a newly discovered organism. It is multicellular, eukaryotic, heterotrophic, lacks a cell wall, and exhibits high mobility and rapid response to stimuli. These characteristics strongly indicate its placement in which kingdom? 26. Which of the following is an INCORRECT pairing regarding the type of fungus and its common reproductive structures/features? 27. The "Kingdom Protista" in Whittaker's classification is considered polyphyletic because: 28. Assertion (A): Diatoms are often referred to as 'jewels of the plant kingdom'. Reason (R): Their cell walls are impregnated with silica, forming intricate and beautiful patterns, and they are major producers in aquatic environments. 29. Consider an organism that is diploid throughout its life cycle, producing haploid gametes via meiosis, which then fuse to form a diploid zygote that develops directly into a new diploid organism. This type of life cycle is characteristic of: 30. Which of the following taxonomic aids provides information for the identification of names of species found in an area, but does not provide descriptive information about the species themselves? 31. A species of bacteria is found to perform photosynthesis, utilizing hydrogen sulfide as an electron donor instead of water, and does not produce oxygen. This organism would be classified as: 32. Which of the following features is shared by both prokaryotic and eukaryotic organisms? 33. The most significant distinction between Bacteria and Archaea, which supports their classification into separate domains, lies in their: 34. A particular group of protozoans moves using pseudopods, captures food by phagocytosis, and sometimes has silica shells. They belong to the phylum: 35. Which of the following is the most appropriate way to represent the scientific name of an organism according to binomial nomenclature rules? 36. An unknown organism is discovered. It is non-motile, absorbs nutrients from decaying organic matter, and its cell wall contains chitin. It reproduces by spores, some of which are flagellated. This organism would be classified under: 37. Assertion (A): All eukaryotic organisms are classified under the Kingdom Protista in Whittaker's Five Kingdom Classification. Reason (R): The Kingdom Protista includes both single-celled and multicellular eukaryotic organisms with diverse modes of nutrition. 38. Which of the following represents a correct sequence of taxonomic categories in ascending order (from smallest to largest)? 39. A biologist identifies an organism with a thalloid body, root-like rhizoids, and an alternation of generations where the gametophyte is the dominant, photosynthetic stage. It requires water for the transfer of male gametes. This organism is most likely a: 40. In the context of taxonomic classification, which of the following statements about 'species' is most accurate and least prone to exceptions or alternative interpretations? 41. A particular group of algae is characterized by having a rigid cellulose cell wall, two flagella (one longitudinal, one transverse in a furrow), and often exhibit bioluminescence. They are a significant component of "red tides." This description best fits: 42. Which of the following taxonomic ranks is defined by fundamental similarities and is generally considered the most inclusive (broadest) rank where organisms share a recent common ancestor, often beyond the scope of a phylum? 43. A student observes a fungal specimen that produces spores exogenously on club-shaped structures. Gills are visible on the underside of its cap. This fungus most likely belongs to which group? 44. Consider two organisms: Organism X is a prokaryote, can survive in highly saline environments, and has a unique cell wall lacking peptidoglycan. Organism Y is a single-celled eukaryote, possesses flagella, and is mixotrophic (photosynthetic and heterotrophic). Which of the following is the most appropriate classification for X and Y, respectively? 45. The primary reason why viruses are often excluded from typical biological classification schemes (like the five-kingdom system) is: 46. Which of the following statements about cyanobacteria is INCORRECT? 47. A scientist identifies an organism that forms a diploid zygote after sexual reproduction, which then undergoes meiosis to produce haploid spores. The dominant vegetative phase of this organism is haploid. This life cycle pattern is characteristic of: 48. Which of the following is the most significant criterion that led to the separation of Fungi from Plantae in Whittaker's five-kingdom classification? 49. A researcher discovers a new species of bacteria that lacks a cell wall and is resistant to penicillin. It obtains nutrients by parasitizing human cells. This organism would be classified under: 50. An aquatic organism is observed to have a chitinous exoskeleton, jointed appendages, and compound eyes. It undergoes ecdysis. To which phylum does it belong?