Botany 2024 Paper I 50 marks Critically examine

Q7

(a) Write an explanatory account of ethnobotany. Give a critical account of whether ethnobotany is a faith, myth or science. 20 (b) Compare the differentiation of xylem and phloem from the cells cut off by cambium. How is a vessel structurally different from a sieve element? 10+5=15 (c) What are the causes of variability in regenerated plants in tissue cultures? Give an account of utility of such variants in improvement of crop plants with examples. 15

हिंदी में प्रश्न पढ़ें

(a) लोकवनस्पति-विज्ञान (एथनोबॉटनी) का एक व्याख्यात्मक विवरण लिखिए। इसका एक आलोचनात्मक विवरण दीजिए कि क्या लोकवनस्पति-विज्ञान एक आस्था, मिथक या विज्ञान है। 20 (b) कैम्बियम द्वारा काटी गयी कोशिकाओं से जायलम और फ्लोएम के विभेदन की तुलना कीजिए। एक वाहिका कोशिका की संरचना, छलनी कोशिका की संरचना से किस प्रकार भिन्न है? 10+5=15 (c) उत्तक संवर्धन से पुनर्जीवित पौधों में परिवर्तनशीलता के क्या कारण हैं? फसलों के सुधार में ऐसे पादपों की उपयोगिता का उदाहरण सहित विवरण दीजिए। 15

Evaluate your answer to this question → See all 2024 Botany questions

Directive word: Critically examine

This question asks you to critically examine. 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

Critically examine demands balanced exposition with evaluative judgment. Structure: Introduction defining ethnobotany's scope (2 marks); Part (a) — 40% word budget: historical development, Richard Schultz's contributions, then systematic critique of faith/myth/science debate with evidence-based reasoning (20 marks); Part (b) — 30%: cambial derivatives, periclinal divisions, xylem vs phloem differentiation pathways, vessel-sieve element structural comparison with diagrams (15 marks); Part (c) — 30%: pre-existing vs induced variation, genetic/epigenetic causes, somaclonal variants in sugarcane (Co 86032), rice, tomato; conclude with integrated synthesis on plant science methodology.

Key points expected

  • (a) Ethnobotany defined as systematic study of plant-human relationships; historical trajectory from primitive societies to formal discipline (R.I. Ford, J.W. Harshberger)
  • (a) Critical evaluation: distinguishes empirical knowledge (science) from ritualistic beliefs (faith/myth) using testable hypotheses, quantitative methods, and falsifiability criteria
  • (a) Evidence from Indian context: sacred groves (Khasi, Bishnoi) containing scientific conservation; Ayurvedic pharmacopoeia yielding modern drugs (reserpine, psoralens)
  • (b) Cambial activity: fusiform initials → periclinal divisions → xylem inward (protoxylem→metaxylem/endarch) vs phloem outward; role of auxin gradients and positional information
  • (b) Structural comparison: vessel — dead at maturity, lignified secondary wall with pits, perforation plates, no protoplasm; sieve element — living, thin cellulose walls, sieve plates with P-protein, persistent ER, enucleate at maturity
  • (c) Causes: pre-existing cellular heterogeneity, de novo mutations (chromosomal: aneuploidy, polyploidy; gene mutations; DNA methylation changes), tissue culture-induced stress (hormone-mediated)
  • (c) Utility: disease resistance (sugarcane mosaic virus-resistant lines), stress tolerance (salt-tolerant rice), improved quality (high-solids tomato); limitations: chimeras, instability, epigenetic reversions
  • (c) Indian examples: somaclonal variants in banana (Nendran), cardamom, sandalwood; CIMAP initiatives for medicinal plants

Evaluation rubric

DimensionWeightMax marksExcellentAveragePoor
Concept correctness22%11Precise definitions across all parts: ethnobotany as interdisciplinary science (not mere folklore); accurate cambial histogenesis terminology (storied/non-storied, anticlinal vs periclinal); correct distinction between somaclonal variation causes (genetic vs epigenetic) with mechanistic clarityBroadly correct definitions with minor errors; conflates ethnobotany with ethnobiology; vague on cambial derivatives; lists somaclonal causes without distinguishing pre-existing vs inducedFundamental misconceptions: treats ethnobotany as only traditional knowledge; confuses procambium with vascular cambium; attributes all variation to mutation without understanding tissue culture stress factors
Diagram / labelling16%8Two precise diagrams: (b) cambial zone showing periclinal divisions with xylem/phloem differentiation stages; vessel-sieve element comparison with annotations for perforation plates, sieve pores, P-protein; clean line work with directional arrowsSingle generic cambium diagram without differentiation stages; basic vessel/tracheid sketch without sieve element detail; adequate but incomplete labellingNo diagrams or irrelevant sketches; confused xylem/phloem orientation; mislabels sieve plates as pit membranes
Examples & nomenclature18%9Rich Indian exemplification: (a) Mehrgarh evidence, Todas of Nilgiris, sacred groves of Western Ghats; (c) specific cultivars (Co 86032, Basmati variants), institutions (CIMAP, NBPGR); taxonomic authorities where relevant; avoids generic Western examplesSome Indian examples (neem, turmeric) but lacking specificity; mentions somaclonal variation in sugarcane without cultivar names; acceptable but not distinguishedNo Indian examples; relies solely on generic international cases (maize, potato); misspells scientific names; conflates somaclonal with gametoclonal variation
Process explanation22%11Clear mechanistic narratives: (a) evolution from descriptive to hypothesis-driven methodology; (b) signal transduction in cambial differentiation (auxin-TF gradients), programmed cell death in vessel maturation vs selective autophagy in sieve elements; (c) stepwise tissue culture-induced variation from callus to organogenesisSequential description without mechanistic depth; lists cambial products chronologically; describes somaclonal variation outcomes without causal pathwaysDescriptive only with no process logic; confuses differentiation with dedifferentiation; presents variation as random without explaining tissue culture-specific selection pressures
Application / ecology22%11Integrated applied perspective: (a) bioprospecting ethics, ABS under Nagoya Protocol, community knowledge documentation; (c) field evaluation protocols for somaclonal variants, RAPD/AFLP confirmation of stability, commercial release pathways (CVRC registration); links to food security and germplasm conservationMentions applications superficially; lists uses without evaluation protocols; weak on regulatory or ecological implicationsNo application context; ignores ethical dimensions of bioprospecting; presents somaclonal variation as unconditionally beneficial without noting instability or field performance issues

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 Botany 2024 Paper I