Q8
(a) Describe the various measures of central tendency of data with suitable examples and discuss their merits and demerits. (20 marks) (b) Define population. Explain the different characteristics of population. (15 marks) (c) Write the systematic position of an oilseed pest. Give an account of its life cycle and the damage caused by this pest. Write a note on its control measures. (15 marks)
हिंदी में प्रश्न पढ़ें
(a) आँकड़ों (डेटा) की केंद्रीय प्रवृत्ति के विभिन्न मापों का उपयुक्त उदाहरणों सहित वर्णन कीजिए तथा उनके गुण और दोषों की चर्चा कीजिए। (20 अंक) (b) जनसंख्या को परिभाषित कीजिए। जनसंख्या की विभिन्न विशेषताओं की व्याख्या कीजिए। (15 अंक) (c) तिलहन के पीड़क का वर्गीकृत स्थान लिखिए। इस पीड़क के जीवन चक्र एवं इसके द्वारा होने वाली क्षति का विवरण दीजिए। इसके नियंत्रण उपायों पर एक टिप्पणी लिखिए। (15 अंक)
Directive word: Describe
This question asks you to describe. 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
Begin with a brief introduction acknowledging the interdisciplinary nature of the question spanning biostatistics, ecology, and economic entomology. For part (a) (20 marks), allocate approximately 40% of content—systematically describe mean, median, and mode with formulas, provide numerical examples (e.g., tiger population data from Project Tiger), and critically weigh merits/demerits including sensitivity to outliers and skewness. For part (b) (15 marks), allocate ~30%—define population emphasizing the biological species concept, then explain characteristics: natality, mortality, sex ratio, age distribution, density, and dispersion patterns with Indian examples like Nilgiri tahr or Gangetic dolphin populations. For part (c) (15 marks), allocate ~30%—select a major oilseed pest (preferably mustard aphid Lipaphis erysimi or tobacco caterpillar Spodoptera litura), state systematic position up to family, diagrammatically represent life cycle stages, describe feeding damage symptoms, and integrate IPM strategies including biocontrol agents like Coccinella septempunctata and resistant varieties such as Pusa Bold. Conclude by synthesizing how statistical tools aid population studies and pest management decisions.
Key points expected
- Part (a): Mathematical definitions, formulas, and worked examples for arithmetic mean, geometric mean, harmonic mean, median, and mode; comparative analysis of merits (simplicity, stability) and demerits (affected by extreme values, amenable to algebraic treatment)
- Part (a): Appropriate choice of measure based on data type—nominal (mode), ordinal (median), interval/ratio (mean); illustration with biological datasets like shell dimensions in molluscs or insect wing measurements
- Part (b): Precise definition of population distinguishing from species and community; explanation of static (sex ratio, age distribution, density) and dynamic (natality, mortality, dispersal) characteristics with mathematical expressions where relevant
- Part (b): Population dispersion patterns (clumped, uniform, random) with ecological determinants; Indian examples such as Asiatic lion population in Gir or snow leopard distribution in Himalayas
- Part (c): Accurate systematic position of chosen oilseed pest (e.g., Lipaphis erysimi: Phylum Arthropoda, Class Insecta, Order Hemiptera, Family Aphididae) with diagnostic characters
- Part (c): Complete life cycle description including egg, nymphal instars, adult stages, and voltinism; damage symptoms specific to oilseed crops (mustard, groundnut, sesame) including honeydew secretion and viral transmission
- Part (c): Integrated pest management components—cultural (crop rotation, trap cropping), biological (parasitoids Diaeretiella rapae, predators Chrysoperla carnea), chemical (selective insecticides like imidacloprid), and resistant varieties
- Synthesis: Connection between statistical measures in (a), population parameters in (b), and pest population dynamics monitoring in (c)—demonstrating quantitative ecology application
Evaluation rubric
| Dimension | Weight | Max marks | Excellent | Average | Poor |
|---|---|---|---|---|---|
| Concept correctness | 22% | 11 | All statistical formulas for central tendency are mathematically precise; population characteristics definitions align with Odum/Krebs terminology; systematic classification follows current taxonomic consensus (e.g., Aphididae placement in Hemiptera not Homoptera); no conceptual errors in life cycle staging or IPM principles | Minor errors in formulas (e.g., missing correction for grouped data) or outdated taxonomic placement; population characteristics listed but confused with community attributes; life cycle stages incomplete or misordered | Fundamental errors such as confusing mean with median calculation, defining population as 'group of organisms of same species' without spatial/temporal boundaries, or placing pest in wrong order/family; IPM confused with exclusive chemical control |
| Diagram / labelling | 18% | 9 | Clear hand-drawn diagrams for part (a) showing frequency distribution curves (normal, skewed) with marked central tendency points; part (b) includes survivorship curves (Types I, II, III) or age pyramid diagrams; part (c) presents annotated life cycle diagram of chosen pest with host plant association and damage symptoms illustrated | Diagrams present but poorly labelled or missing key structures; survivorship curves drawn without species examples; life cycle diagram lacks stage durations or host tissue specificity | No diagrams despite visual demands of question; or diagrams copied without understanding (e.g., wrong insect order morphology); labels missing or incorrect; diagrams decorative without informational value |
| Examples & nomenclature | 20% | 10 | Indian-specific examples throughout: for (a)—tiger census data, fish landing statistics; for (b)—endangered species like Great Indian Bustard population dynamics; for (c)—specific oilseed pest (Lipaphis erysimi on Brassica juncea or Spodoptera litura on Arachis hypogaea) with correct binomials, authorities, and crop scientific names | Generic examples without Indian context; correct binomials but missing authorities; pest identified to species but wrong host association; statistical examples from non-biological domains | No specific examples; invented or misspelled scientific names; confusion between pest species (e.g., confusing aphid with whitefly); examples contradict biological reality (e.g., parthenogenetic reproduction in incorrectly identified pest) |
| Process explanation | 22% | 11 | Stepwise calculation demonstration for at least two measures in (a); mechanistic explanation of how population characteristics emerge from individual life histories in (b); sequential developmental stages with environmental triggers (temperature, photoperiod) in (c); logical flow from identification → biology → damage → management | Calculations stated without showing steps; population characteristics listed as static facts without interconnection; life cycle described as bullet points without developmental physiology; management measures listed without prioritization or integration logic | Processes described backwards or illogically; calculations fundamentally wrong; no understanding of how pest population builds to economic threshold; management recommendations contradict life cycle biology (e.g., spraying during non-vulnerable pupal stage) |
| Evolutionary / applied context | 18% | 9 | Critical evaluation of when each central tendency measure is evolutionarily informative (e.g., mode for polymorphism); population characteristics linked to r/K selection theory; pest management grounded in resistance management principles, biocontrol compatibility, and sustainable agriculture goals; mentions PMFME or NMHS relevance | Brief mention of evolutionary significance without elaboration; IPM described without resistance management considerations; no connection to national agricultural priorities or conservation status | No evolutionary or applied perspective; purely descriptive answer; recommends banned pesticides (e.g., monocrotophos, endosulfan); ignores ecological consequences of management interventions |
Practice this exact question
Write your answer, then get a detailed evaluation from our AI trained on UPSC's answer-writing standards. Free first evaluation — no signup needed to start.
Evaluate my answer →More from Zoology 2024 Paper I
- Q1 Write short notes on the following in about 150 words each: (a) Concept and organization of Coelom (10 marks) (b) Metamorphosis in Insects…
- Q2 (a) Explain the general features, life cycle and pathogenicity of Fasciola. (20 marks) (b) Define Autogamy. Explain the mechanism of autoga…
- Q3 (a) Describe the different larval forms of Crustaceans with suitable diagrams. (20 marks) (b) What are coral reefs ? Describe the different…
- Q4 (a) Give an illustrated account of integument and its derivatives in vertebrates with suitable diagrams. (20 marks) (b) What is Polymorphis…
- Q5 Write short notes on the following in about 150 words each: (a) Food Web (10 marks) (b) Biological Rhythms (10 marks) (c) AIDS (10 marks) (…
- Q6 (a) What is ecological succession ? Explain the different types and theories of ecological succession. (20 marks) (b) Explain Aggressive an…
- Q7 (a) Mention the causative agent and means of spread of malaria. Also describe symptoms, diagnosis, treatment and preventive measures of mal…
- Q8 (a) Describe the various measures of central tendency of data with suitable examples and discuss their merits and demerits. (20 marks) (b)…