All 8 questions from UPSC Civil Services Mains Zoology 2023 Paper I (400 marks total). Every stem reproduced in full, with directive-word analysis, marks, word limits, and answer-approach pointers.
8Questions
400Total marks
2023Year
Paper IPaper
Topics covered
General zoology topics (1)Protozoa, Annelida and Insecta (1)Platyhelminthes, Mammalian evolution and Echinodermata (1)Endocrinology, Nematoda and Porifera (1)Ecology, ethology, pathology and biostatistics (1)Biostatistics, ecology and animal behaviour (1)Applied zoology, wildlife conservation and ethology (1)Immunology, veterinary science and animal behaviour (1)
A
Q1
50M150wCompulsorywrite short notesGeneral zoology topics
Write short notes on the following in about 150 words each:
(a) Erythrocytic schizogony (10 marks)
(b) Statocyst of medusa (10 marks)
(c) Evolutionary status of Onychophora (10 marks)
(d) Neoteny (10 marks)
(e) Migration in birds (10 marks)
हिंदी में पढ़ें
निम्नलिखित में से प्रत्येक पर 150 शब्दों में संक्षिप्त टिप्पणी लिखिए :
(a) रक्ताण्विक विखण्डनिजन (10 अंक)
(b) मेड्यूसा की संतुलन-पुटी (स्टैटोसिस्ट) (10 अंक)
(c) ओनिकोफोरा की विकासवादी स्थिति (10 अंक)
(d) चिरभूणता (10 अंक)
(e) पक्षियों में प्रवास (10 अंक)
Answer approach & key points
Framework: Zoology, Paper 1. (a) write short notes: define > 3-4 key features > one example > one-line significance | (b) write short notes: define > 3-4 key features > one example > one-line significance | (c) write short notes: define > 3-4 key features > one example > one-line significance | (d) write short notes: define > 3-4 key features > one example > one-line significance | (e) write short notes: define > 3-4 key features > one example > one-line significance Full marks: Precise definitions, correct sequences, named examples, and clear evolutionary/functional links.
Asexual cycle inside RBCs after hepatic phase
Ring, trophozoite and schizont stages; haemozoin
12-24 merozoites released by RBC rupture
Periodic paroxysm: 48 h vivax/falciparum, 72 h malariae
Organ of balance at umbrella margin
Sensory hairs, statolith, lithocyte
Hydromedusae near tentacle bases; rhopalia in scyphomedusae
Tilt moves statolith, impulses via nerve ring to muscles
(a) Define conjugation. Explain the mechanism of conjugation in Paramecium. Also give its significance. (20 marks)
(b) Describe the different stages of life cycle of leech with the help of suitable diagram. (15 marks)
(c) Describe the respiratory organs and mechanism of respiration in cockroach. (15 marks)
हिंदी में पढ़ें
(a) संयुग्मन को परिभाषित कीजिए। पैरामीशियम में संयुग्मन की क्रियाविधि की व्याख्या कीजिए। इसका महत्व भी बताइए। (20 अंक)
(b) जोंक के जीवन-चक्र की विभिन्न अवस्थाओं का उपयुक्त चित्र की सहायता से वर्णन कीजिए। (15 अंक)
(c) तिलचट्टा (कॉक्रोच) में श्वसन अंगों और श्वसन की क्रियाविधि का वर्णन कीजिए। (15 अंक)
Answer approach & key points
Framework: Zoology Paper 1: Define > Structure/Mechanism > Diagram > Example. (a) explain: definition/context > points in order > small example > short close | (b) describe: define > structure or process in order > labelled diagram > significance | (c) describe: define > structure or process in order > labelled diagram > significance Full marks: Precise definitions, stepwise mechanisms, labelled diagrams, and specific taxonomic examples.
Temporary union of opposite mating types with exchange of micronuclei
Meiosis of micronucleus, three degenerate, stationary and migratory pronuclei
Synkaryon, three divisions to eight nuclei, exconjugant divisions giving four daughters
50MexplainPlatyhelminthes, Mammalian evolution and Echinodermata
(a) Explain the general features, life cycle and pathogenicity of Taenia. (20 marks)
(b) Give an illustrated account of origin of mammals. (15 marks)
(c) Describe the perivisceral coelom and endoskeleton of Asterias. (15 marks)
हिंदी में पढ़ें
(a) टीनिया के सामान्य लक्षणों, जीवन-चक्र और रोगजनकता का वर्णन कीजिए। (20 अंक)
(b) स्तनधारियों की उत्पत्ति का सचित्र विवरण दीजिए। (15 अंक)
(c) ऐस्टीरिएस के परिवर्तं प्रगुहा और अंतःकंकाल का वर्णन कीजिए। (15 अंक)
Answer approach & key points
Framework: Zoology Paper 1: Define > Structure/Mechanism > Diagram > Example. (a) explain: definition/context > points in order > small example > short close | (b) account for: state the phenomenon > the causes in order of weight > conclusion | (c) describe: define > structure or process in order > labelled diagram > significance Full marks: Precise taxon names, fully labelled diagrams, clear mechanism of pathogenicity/evolution, and accurate anatomical descriptions.
Scolex with suckers and rostellum hooks; strobila of proglottids; acoelomate parasite without gut
Pig as intermediate host: oncosphere, cysticercus in muscle
Man infected by measly pork, adult in intestine
Taeniasis versus cysticercosis and neurocysticercosis
(a) Draw a well-labelled diagram of adrenal gland and discuss the functions of its hormones. (20 marks)
(b) Describe the general features and life cycle of Ascaris. (15 marks)
(c) What are the skeletal elements of sponges? Describe the structure and types of various skeletal elements found in sponges. (15 marks)
हिंदी में पढ़ें
(a) अधिवृक्क ग्रंथि का एक सुचिहित चित्र बनाइए और इसके हार्मोनों के कार्यों का वर्णन कीजिए। (20 अंक)
(b) ऐस्कैरिस के सामान्य लक्षणों और जीवन-चक्र का वर्णन कीजिए। (15 अंक)
(c) स्पंज के कंकाल तत्व क्या हैं? स्पंज में पाए जाने वाले विभिन्न कंकाल तत्वों की संरचना एवं प्रकारों का वर्णन कीजिए। (15 अंक)
Answer approach & key points
Framework: UPSC Zoology Paper 1. (a) discuss: intro > 3-4 dimensions > example > balanced close | (b) describe: define > structure or process in order > labelled diagram > significance | (c) describe: define > structure or process in order > labelled diagram > significance Full marks: Precise diagrams, accurate mechanisms, and specific taxonomic details.
Labelled diagram: capsule, three cortical zones, medulla, vein
Aldosterone from glomerulosa: Na+ and water retention
Cortisol from fasciculata and androgens from reticularis
Adrenaline and noradrenaline from medulla; disorders
Sexual dimorphism: female 20-40 cm straight tail, male 15-30 cm curved with spicules
Thick cuticle, triradiate mouth, pseudocoelomate
Monogenetic: egg in soil, L2 infective; ingestion
Migration via portal vein, liver, heart, lungs, trachea to intestine
Spicules and spongin as skeletal elements
Calcareous versus siliceous; megascleres and microscleres
Monaxon, triaxon, tetraxon, polyaxon with examples
50M150wCompulsorywrite short notesEcology, ethology, pathology and biostatistics
Write short notes on the following in about 150 words each:
(a) Ecological niche (10 marks)
(b) Instinct behaviour in animals (10 marks)
(c) Pathogenesis of cholera (10 marks)
(d) Amniocentesis (10 marks)
(e) Lotka-Volterra model (10 marks)
हिंदी में पढ़ें
निम्नलिखित में से प्रत्येक पर 150 शब्दों में संक्षिप्त टिप्पणी लिखिए :
(a) पारिस्थितिक निकेत (10 अंक)
(b) प्राणियों में सहज व्यवहार (10 अंक)
(c) हैजा का रोगजनन (10 अंक)
(d) उल्बवेधन (10 अंक)
(e) लोटका-वोल्टेरा मॉडल (10 अंक)
Answer approach & key points
Framework: Zoology, Paper 1. (a) write short notes: define > 3-4 key features > one example > one-line significance | (b) write short notes: define > 3-4 key features > one example > one-line significance | (c) write short notes: define > 3-4 key features > one example > one-line significance | (d) write short notes: define > 3-4 key features > one example > one-line significance | (e) write short notes: define > 3-4 key features > one example > one-line significance Full marks: Precise definitions, specific examples, and clear mechanisms for all parts.
Functional role plus range of conditions and resources; Hutchinson n-dimensional hypervolume
Fundamental versus realised niche
Gause's exclusion and resource partitioning
Indian example such as lion-tailed macaque
Inborn stereotyped behaviour without learning
Fixed action pattern and sign stimulus with innate releasing mechanism
Tinbergen's stickleback red-belly experiment
Value for survival
Vibrio cholerae ingested, adheres by TCP in small intestine
Cholera toxin A1B5 binds GM1
ADP-ribosylation of Gs alpha, high cAMP, CFTR opening
Cl- and bicarbonate efflux, rice-water diarrhoea, dehydration
Fluid withdrawn at 15-20 weeks under ultrasound, 15-20 mL
Karyotyping of amniocytes for Down, Edwards, Patau
50MexplainBiostatistics, ecology and animal behaviour
(a) Define regression. Explain different methods and applications of regression analysis. (20 marks)
(b) Define food chain. Describe different types of food chain with suitable examples. (15 marks)
(c) Describe the phenomenon of altruism and kinship in studying animal behaviour with suitable examples. (15 marks)
हिंदी में पढ़ें
(a) समाश्रयण को परिभाषित कीजिए। समाश्रयण विश्लेषण की विभिन्न विधियों और अनुप्रयोगों की व्याख्या कीजिए। (20 अंक)
(b) खाद्य श्रृंखला को परिभाषित कीजिए। विभिन्न प्रकार की खाद्य श्रृंखलाओं का उपयुक्त उदाहरणों सहित वर्णन कीजिए। (15 अंक)
(c) प्राणि व्यवहार के अध्ययन में परोपकारिता और नातेदारी की परिघटना का उपयुक्त उदाहरणों सहित वर्णन कीजिए। (15 अंक)
Answer approach & key points
Framework: Zoology Paper 1: Define > Structure/Mechanism > Diagram > Example. (a) explain: definition/context > points in order > small example > short close | (b) describe: define > structure or process in order > labelled diagram > significance | (c) describe: define > structure or process in order > labelled diagram > significance Full marks: Precise definitions, clear distinction of methods/types, specific biological examples, and correct application of theories.
Definition and contrast with correlation
Simple linear regression with least squares and regression lines
Multiple, polynomial and logistic regression
Applications in ecology, growth, epidemiology, fisheries, genetics
Linear energy transfer with trophic levels and 10 per cent transfer
Grazing chain with examples
Detritus chain with examples
Parasitic chain and link to food web
Altruism as cost to actor and benefit to recipient
Hamilton's rule rB>C and inclusive fitness
Kin examples: alarm calls, helpers, social insects with haplodiploidy
50MdescribeApplied zoology, wildlife conservation and ethology
(a) What is lac culture? Explain the life cycle of lac insect and describe cultivation and processing of lac in India. Also add a note on its economic importance. (20 marks)
(b) What is Project Tiger? Discuss the various threats and conservation strategies to protect tigers in India. (15 marks)
(c) Define imprinting. Describe the mechanism of imprinting in animals with suitable examples. (15 marks)
हिंदी में पढ़ें
(a) लाख (लाक्षा) संवर्धन क्या है? लाख कीट के जीवन-चक्र की व्याख्या कीजिए और भारत में लाख की खेती और प्रसंस्करण का वर्णन कीजिए। इसके आर्थिक महत्व पर एक टिप्पणी भी लिखिए। (20 अंक)
(b) बाघ परियोजना (प्रोजेक्ट टाइगर) क्या है? भारत में बाघों की सुरक्षा के लिए विभिन्न खतरों और संरक्षण रणनीतियों का वर्णन कीजिए। (15 अंक)
(c) अध्यंकन को परिभाषित कीजिए। प्राणियों में अध्यंकन की क्रियाविधि का उपयुक्त उदाहरणों सहित वर्णन कीजिए। (15 अंक)
Answer approach & key points
Framework: UPSC Zoology Paper 1. (a) explain: definition/context > points in order > small example > short close | (b) discuss: intro > 3-4 dimensions > example > balanced close | (c) define: precise definition > the distinguishing feature > one example Full marks: Precise definitions, detailed mechanisms, specific examples, and clear structure.
Kerria lacca on host trees; resin, dye, wax
Life cycle: crawler, settling, resin cell, male and female development
Hosts palas, ber, kusum; inoculation with brood lac; sticklac harvest
Sticklac to seedlac to shellac; uses and livelihood
Launched 1 April 1973 at Corbett; centrally sponsored
58 tiger reserves in 18 states; 3,682 tigers in 2022
50MexplainImmunology, veterinary science and animal behaviour
(a) What is ELISA? Explain the principle, types, procedure and applications of ELISA. (20 marks)
(b) Describe the symptoms, diagnosis, treatment and preventive measures of livestock diseases. (15 marks)
(c) Define crypsis. Explain the types and mechanism of crypsis in animals with suitable examples. (15 marks)
हिंदी में पढ़ें
(a) ई० एल० आई० एस० ए० क्या है? ई० एल० आई० एस० ए० के सिद्धांत, प्रकार, प्रक्रिया और अनुप्रयोगों की व्याख्या कीजिए। (20 अंक)
(b) पशुधन रोगों के लक्षण, निदान, उपचार और रोकथाम के उपायों का वर्णन कीजिए। (15 अंक)
(c) गोपकता (क्रिप्सिस) को परिभाषित कीजिए। प्राणियों में गोपकता के प्रकार और क्रियाविधि का उपयुक्त उदाहरणों सहित वर्णन कीजिए। (15 अंक)
Answer approach & key points
Framework: UPSC Zoology Paper 1. (a) explain: definition/context > points in order > small example > short close | (b) describe: define > structure or process in order > labelled diagram > significance | (c) explain: definition/context > points in order > small example > short close Full marks: Comprehensive, accurate, with specific examples and clear mechanisms.
Enzyme-labelled antibody gives coloured product from substrate in a coated well