Zoology 2024 Paper I 50 marks Explain

Q2

(a) Explain the general features, life cycle and pathogenicity of Fasciola. (20 marks) (b) Define Autogamy. Explain the mechanism of autogamy in Paramecium. Also give its significance. (15 marks) (c) Compare and contrast Telencephalon of the brain in Vertebrates. (15 marks)

हिंदी में प्रश्न पढ़ें

(a) फेसिओला के सामान्य लक्षणों, जीवन चक्र और रोगजनकता की व्याख्या कीजिए। (20 अंक) (b) स्वक्यूमन को परिभाषित कीजिए। परामीशियम में स्वक्यूमन की क्रियाविधि की व्याख्या कीजिए। इसका महत्व भी बताइए। (15 अंक) (c) कशेरुकियों में मस्तिष्क के उन्मस्तिष्क की तुलना कीजिए और अंतर बताइए। (15 अंक)

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Directive word: Explain

This question asks you to explain. The directive word signals the depth of analysis expected, the structure of your answer, and the weight of evidence you must bring.

See our UPSC directive words guide for a full breakdown of how to respond to each command word.

How this answer will be evaluated

Approach

The directive 'explain' demands clear, logical exposition with cause-effect relationships across all three parts. Allocate approximately 40% of time/words to part (a) given its 20 marks, and roughly 30% each to parts (b) and (c). Structure with brief introductions for each sub-part, detailed body covering all directive components, and integrated conclusions highlighting significance or comparative synthesis. For part (c), ensure the comparison is vertebrate-wide, not mammal-centric.

Key points expected

  • Part (a): Fasciola morphology (tegument, suckers, digestive system), complete life cycle with miracidium, sporocyst, redia, cercaria, metacercaria stages, and pathogenicity including hepatic damage, cholangitis, and economic impact in Indian livestock
  • Part (b): Precise definition of autogamy, detailed mechanism in Paramecium involving micronuclear events, nuclear reorganization, and homozygosity outcomes; significance for genetic uniformity and survival advantages
  • Part (c): Comparative anatomy of telencephalon across vertebrate classes (cyclostomes, fishes, amphibians, reptiles, birds, mammals), emphasizing pallial evolution, corpus striatum modifications, and cerebral hemisphere development
  • Integration of diagrams for Fasciola life cycle, Paramecium nuclear changes, and telencephalic cross-sections showing evolutionary progression
  • Nomenclature accuracy: Fasciola hepatica/gigantica distinction, Paramecium caudatum/aurelia, and correct anatomical terms (pallium, archipallium, neopallium, corpus striatum)
  • Applied context: Fascioliasis control measures in Indian veterinary practice, autogamy's role in ciliate genetics research, and telencephalic evolution correlating with behavioral complexity

Evaluation rubric

DimensionWeightMax marksExcellentAveragePoor
Concept correctness22%11Demonstrates flawless understanding across all three parts: accurate Fasciola taxonomy and pathology, correct micronuclear behavior in autogamy, and precise homologous structures in telencephalic evolution without conflating classesShows generally correct concepts with minor errors in life cycle sequence, nuclear division details, or vertebrate comparisons; some confusion between autogamy and conjugationFundamental misconceptions such as incorrect host identification, confusing autogamy with autotomy, or describing mammalian brains as representative of all vertebrates
Diagram / labelling18%9Provides three well-executed diagrams: Fasciola adult with labeled reproductive system and life cycle stages; Paramecium showing nuclear changes during autogamy; comparative telencephalic sections across 3+ vertebrate classes with homologous structures indicatedIncludes at least two diagrams with adequate labeling; missing some critical structures like flame cells in Fasciola or nuclear configurations in Paramecium; vertebrate comparisons lack clear homologiesSingle or no diagram, poorly drawn with incorrect proportions, missing labels for key structures, or diagrams that misrepresent the biological reality
Examples & nomenclature18%9Uses precise binomial nomenclature (Fasciola hepatica, F. gigantica, Paramecium caudatum), cites specific Indian examples (endemic areas like Kashmir valley for fascioliasis), and names representative species for each vertebrate class in telencephalic comparisonGenerally correct nomenclature with occasional lapses (e.g., missing species epithet), generic rather than region-specific examples, and incomplete vertebrate representationIncorrect scientific names, confused common names, no Indian context for Fasciola epidemiology, or failure to name specific vertebrate examples in part (c)
Process explanation22%11Clear sequential exposition: Fasciola life cycle with host alternation and larval transformations; stepwise micronuclear division and macronuclear regeneration in autogamy; developmental sequence of telencephalic elaboration from paleopallium to neopalliumAdequate process description but with gaps in sequence, missing intermediate stages, or unclear causal mechanisms; telencephalic description lacks developmental perspectiveDisorganized or incomplete processes, missing critical stages (e.g., metacercaria encystment, second meiotic division in autogamy), or purely static descriptions without mechanism
Evolutionary / applied context20%10Integrates significance throughout: economic and zoonotic importance of fascioliasis with WHO/FAO relevance; evolutionary significance of autogamy for clonal survival and genetic research utility; telencephalic evolution correlating with ecological adaptations and behavioral complexity across vertebrate phylogenyMentions significance superficially, treats applied aspects as afterthoughts, or provides generic statements without specific linkage to the organisms discussedCompletely misses applied dimensions, no mention of control strategies for Fasciola, ignores autogamy's genetic consequences, or describes telencephalon without evolutionary interpretation

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