Maharashtra HSC GFC cheat sheet

Earth's layers by composition: crust (oceanic ~5-10 km, basaltic; continental ~30-70 km, granitic), mantle (to ~2900 km, peridotite), core (Fe-Ni; outer core liquid, inner core solid).

By physical behaviour: lithosphere (crust + rigid upper mantle, ~100 km), asthenosphere (partially molten, plastic, source of magma), mesosphere, outer core, inner core.

Seismic evidence: P-waves (compressional, travel through solids and liquids, fastest); S-waves (shear, cannot pass liquids) - the S-wave shadow zone proves a liquid outer core.

Moho = crust-mantle boundary (P-wave velocity jump); Gutenberg discontinuity ~2900 km = mantle-core boundary; Lehmann discontinuity = inner-core boundary.

Wegener's continental drift evidence: jigsaw fit of continents, matching fossils (Glossopteris), matching rock strata, glacial striations, paleoclimatic belts.

Plate boundaries: divergent (mid-ocean ridge, rift valley, new crust, shallow quakes), convergent (ocean-ocean: island arcs; ocean-continent: volcanic mountain arcs; continent-continent: fold mountains), transform (shear, no crust created).

Sea-floor spreading (Hess): symmetric magnetic stripe anomalies, age of ocean floor increasing away from ridges, thin sediment cover near ridges, pillow basalts.

Driving mechanisms: mantle convection, slab pull (dominant), ridge push; hotspots (Hawaii, Réunion) form volcanic chains independent of plate margins.

India-Eurasia collision: Indian plate moving north ~5 cm/yr; produced Himalaya, Main Boundary Thrust, and makes the Deccan Traps (flood basalt, ~66 Ma, K-Pg boundary) a key Indian example.

Mineral definition: naturally occurring, inorganic, solid, definite chemical composition, ordered atomic structure. Silicate tetrahedron (SiO4) is the basic unit of most crustal minerals.

Mohs hardness scale (1-10): talc, gypsum, calcite, fluorite, apatite, orthoclase, quartz, topaz, corundum, diamond. Quartz (7) scratches glass (~5.5); fingernail ~2.5; copper coin ~3.5.

Key rock-forming minerals: quartz (SiO2), feldspar (most abundant group), mica (biotite/muscovite, perfect cleavage), olivine, pyroxene, amphibole, calcite (fizzes with dilute HCl), gypsum, clay minerals.

Igneous rocks: intrusive/plutonic (slow cooling, coarse, phaneritic - granite, gabbro, dolerite) vs extrusive/volcanic (fast cooling, fine, aphanitic - basalt, rhyolite); porphyritic = two-stage cooling; glassy = obsidian; vesicular = pumice/scoria.

Igneous classification by silica: felsic (granite, rhyolite - high SiO2, light, viscous), intermediate (diorite, andesite), mafic (gabbro, basalt - low SiO2, dark, fluid).

Sedimentary rocks: clastic (conglomerate, sandstone, shale - classified by grain size), chemical (limestone, rock salt, gypsum), organic (coal, some limestone). Principle of superposition and fossils used for relative dating.

Metamorphic rocks: foliated (slate→phyllite→schist→gneiss, increasing grade) and non-foliated (marble from limestone, quartzite from sandstone). Index minerals (chlorite, biotite, garnet, staurolite, sillimanite) indicate grade.

Rock cycle: igneous → weathering/erosion → sediment → compaction/cementation → sedimentary → heat/pressure → metamorphic → melting → magma → igneous; any rock can shortcut to any other type.

Indian examples: Deccan basalt (igneous), Vindhyan sandstone and limestone (sedimentary), Aravalli and Eastern Ghats gneiss/schist (metamorphic), Jharia/Raniganj coal (organic sedimentary).

Weathering: physical (frost wedging, exfoliation/unloading, thermal, salt), chemical (solution, oxidation, hydrolysis, carbonation), biological (root wedging, lichen). Weathering in situ; erosion involves transport.

Mass wasting: creep (slowest), solifluction, slump, debris flow, mudflow, rockslide, rockfall - driven by gravity, triggered by water saturation, slope angle, removal of toe support.

Fluvial landforms: V-shaped valley, gorge, waterfall, potholes, meander, oxbow lake, floodplain, natural levee, alluvial fan, delta, point bar (deposition) vs cut bank (erosion).

Fluvial processes: erosion (hydraulic action, abrasion, attrition, solution), transport (traction, saltation, suspension, solution), deposition. Graded profile = equilibrium between erosion and deposition.

Karst: formed by carbonation of limestone; features include sinkhole/doline, uvala, polje, cave, stalactite (ceiling), stalagmite (floor), pillar, disappearing stream.

Glacial landforms: erosional - cirque, arête, horn, U-shaped valley, hanging valley, roche moutonnée; depositional - moraine (lateral, medial, terminal), drumlin, esker, outwash plain, erratic.

Coastal landforms: erosional - cliff, wave-cut platform, sea cave, arch, stack; depositional - beach, spit, bar, tombolo, lagoon. Longshore drift moves sediment along the shore.

Aeolian (wind) landforms: deflation hollow, yardang, mushroom rock, barchan (crescent, horns downwind), seif dune, loess deposits.

Groundwater and river profile: water table, aquifer vs aquiclude, spring, artesian well; river cycle of erosion (youth, mature, old age) and Davisian peneplain concept.

Champion and Seth (1968) forest type classification for India: 16 major groups; key types include tropical wet evergreen, tropical semi-evergreen, tropical moist deciduous, tropical dry deciduous, tropical thorn, subtropical pine, montane temperate, alpine.

Rainfall-linked pattern (Champion & Seth): tropical wet evergreen >250 cm; semi-evergreen 200-250 cm; moist deciduous 100-200 cm; dry deciduous 70-100 cm; thorn <70 cm.

Sal (Shorea robusta) dominates moist deciduous central India; teak (Tectona grandis) dominates dry/moist deciduous peninsular India; deodar (Cedrus deodara) and blue pine in Himalayan temperate; sundari (Heritiera fomes) in Sundarbans mangroves.

Forest ecology terms: canopy layers (emergent, canopy, understorey, shrub, herb), stratification, crown cover, density, basal area, frequency, abundance, importance value index (IVI = relative density + relative frequency + relative dominance).

Succession: primary vs secondary; hydrarch (wet to dry) vs xerarch (dry to wet); pioneer species, seral stages, climax community; gap-phase dynamics in tropical forests.

Trophic structure: producers, consumers, decomposers; food chain, food web, ecological pyramid (energy always upright, ~10% transfer); nutrient cycling (litter fall, decomposition, mycorrhiza).

Mangroves: halophytic, pneumatophores, viviparous germination, salt tolerance, coastal protection; India's major mangroves - Sundarbans (largest), Bhitarkanika, Pichavaram, Godavari-Krishna delta.

Forest types by altitude in Himalaya: tropical foothills, subtropical (up to ~1500 m), temperate (1500-3300 m), alpine (above ~3300 m, stunted krummholz and meadows/bugyals).

Silviculture = art and science of raising and tending forest crops; silvics = study of life history and growth of trees. Even-aged vs uneven-aged stands; pure vs mixed stands.

Silvicultural systems: high forest (clear felling, shelterwood, seed tree, selection) and coppice (simple coppice, coppice with standards); clear felling suits light-demanding species, selection suits shade-tolerant species.

Regeneration: natural (seed, coppice, root sucker) vs artificial (planting, sowing, direct seeding); nursery practices - seed treatment, bed preparation, pricking out, root trainer, hardening.

Tending operations: weeding, cleaning, thinning (pre-commercial, crown thinning, low thinning, mechanical), pruning, girdling, climber cutting. Thinning increases growth of retained trees.

Rotation = period between regeneration and final felling; felling cycle = interval between successive fellings in selection forest; increment (CAI, MAI) and yield regulation.

Silvicultural characters: light demand (shade tolerance), frost hardiness, drought resistance, fire resistance, coppicing power, root sucker production, soil improvement.

Working Plan = written scheme for felling, regeneration and protection over a forest division for a fixed period; sustained yield principle; JFM (Joint Forest Management, 1990) and FRA 2006 involve communities.

Agroforestry and social forestry: taungya system, farm forestry, community forestry, strip plantation, shelterbelts; nitrogen-fixing species (Dalbergia sissoo, Acacia nilotica, Leucaena) improve soil.

Timber classification: hardwoods (angiosperms - teak, sal, rosewood, mahogany) vs softwoods (gymnosperms - pine, deodar, fir, spruce); softwoods are generally lighter and easier to work.

Wood anatomy: heartwood (dark, dead, durable) vs sapwood (light, living, conducts sap); annual rings, earlywood/latewood, vessels, tracheids, rays.

Wood properties: specific gravity, moisture content, shrinkage and swelling, seasoning (air, kiln, water), durability, strength; defects - knots, shakes, checks, warp, decay, insect borer.

Timber uses and products: sawntimber, plywood, veneer, particle board, fibreboard, MDF, paper and pulp, rayon, matchwood, railway sleepers, charcoal, wood gas.

NTFP categories: bamboo, cane/rattan, fodder, fuelwood, edible fruits and nuts, honey, wax, resin, gum, tannin, dyes, medicinal plants, fibres, leaves (tendu, sal), essential oils, lac, silk.

Tendu (Diospyros melanoxylon) leaves for bidi, sal seed and leaves, mahua (Madhuca) flowers and seed, bamboo (Bambusa, Dendrocalamus), tendu/kendu and lac (Kerria lacca) are major Indian NTFP.

Resin tapping: chir pine oleoresin gives rosin and turpentine; tapping methods (French, borehole, rill); gum arabic from Acacia senegal; tragacanth; natural rubber from Hevea brasiliensis.

Sustainable harvest principles: maximum sustainable yield, rotational harvesting, non-destructive extraction, value addition, certification (FSC), and NTFP marketing through cooperatives and MSP-like support.

Biodiversity levels: genetic, species, ecosystem; India is a megadiverse country with 4 biodiversity hotspots (Himalaya, Indo-Burma, Western Ghats-Sri Lanka, Sundaland/Nicobar) and ~2.4% of world land area.

IUCN Red List categories (in order of increasing threat): Least Concern, Near Threatened, Vulnerable, Endangered, Critically Endangered, Extinct in the Wild, Extinct; plus Data Deficient and Not Evaluated.

In-situ conservation: national parks, wildlife sanctuaries, biosphere reserves, sacred groves, community reserves, conservation reserves. Ex-situ: zoos, botanical gardens, seed banks, cryopreservation, gene banks.

Indian protected area facts: Project Tiger (1973), Project Elephant (1992), Wildlife (Protection) Act 1972, Biological Diversity Act 2002, Forest Conservation Act 1980, CITES regulates international trade.

Flagship/endemic Indian species: tiger, Asiatic lion (Gir), one-horned rhino (Kaziranga), Asiatic elephant, Great Indian bustard, snow leopard, Nilgiri tahr, lion-tailed macaque, gharial, Gangetic dolphin.

Threats to biodiversity: habitat loss and fragmentation (main cause), overexploitation, invasive alien species (Lantana, Parthenium, water hyacinth), pollution, climate change, disease.

Conservation genetics concepts: inbreeding depression, genetic drift, minimum viable population, metapopulation, corridors, keystone/umbrella/flagship/indicator species.

Ecosystem services: provisioning (food, timber, water), regulating (climate, flood control, pollination), cultural (recreation, spiritual), supporting (nutrient cycling, soil formation); carbon sequestration and REDD+.

Air pollutants: primary (SO2, NOx, CO, particulate matter, hydrocarbons) vs secondary (ozone, PAN, sulfuric and nitric acid); sources - thermal power, vehicles, industry, biomass burning.

Air quality standards: PM10, PM2.5, SO2, NO2, CO, O3, lead, benzene; National Ambient Air Quality Standards (NAAQS) in India; AQI categories from Good to Severe.

Greenhouse gases and GWP: CO2 (1), CH4 (~28), N2O (~265), CFCs (thousands), SF6 (highest); greenhouse effect warms Earth's surface; enhanced effect from human emissions.

Climate change evidence and impacts: rising global mean temperature, sea-level rise, glacier retreat, coral bleaching, shifting monsoon, extreme events; IPCC reports and Representative Concentration Pathways (RCPs).

International agreements: UNFCCC (1992), Kyoto Protocol (1997, binding targets), Paris Agreement (2015, NDCs, 1.5-2°C goal), Montreal Protocol (ozone-depleting substances), Kigali Amendment (HFCs).

Water pollution: BOD, COD, DO, eutrophication (nutrient enrichment), heavy metals (Hg, Pb, Cd, As), pesticides, thermal pollution, oil spills; WHO and CPCB standards.

Soil and noise pollution: soil salinity, pesticide residue, heavy metals, solid waste and e-waste; noise measured in dB(A), thresholds ~65 dB day / 55 dB night residential; effects on hearing.

Mitigation and adaptation: renewable energy, energy efficiency, carbon tax and cap-and-trade, carbon sequestration and afforestation, climate-smart agriculture, disaster risk reduction.

Resource classification: renewable vs non-renewable; potential, actual, reserve; biotic vs abiotic; stock, flow, fund resources. Sustainable use keeps harvest ≤ regeneration rate.

Sustainable development (Brundtland Report 1987, Our Common Future): meeting present needs without compromising future generations' ability to meet theirs; three pillars - economic, social, environmental.

SDGs: 17 Sustainable Development Goals (2015-2030); SDG 6 clean water, SDG 13 climate action, SDG 15 life on land, SDG 14 life below water are directly relevant to forestry and conservation.

Watershed management: contour bunding, check dams, percolation tanks, afforestation, gully plugging, and participatory watershed development improve groundwater recharge and reduce soil erosion.

Soil conservation: contour ploughing, terracing, strip cropping, shelterbelts, check dams, crop rotation, organic matter addition; soil erosion types - sheet, rill, gully, splash, wind erosion.

Energy resources: conventional (coal, oil, gas, hydro, nuclear) vs non-conventional (solar, wind, biomass, biogas, geothermal, tidal); energy efficiency and conservation; India's renewable targets.

Environmental impact assessment (EIA) and environmental audit; Environmental Protection Act 1986; polluter pays, precautionary principle, public trust doctrine; EIA notification categories A and B.

Community-based management: Joint Forest Management, FRA 2006, sacred groves, traditional ecological knowledge, ecotourism, payment for ecosystem services, carbon credits and green economy.

Map reading: scale (RF, statement, graphical), grid references (four-figure and six-figure), contour lines (close = steep, wide = gentle), spot heights, benchmarks, and conventional symbols.

Compass and bearings: magnetic north vs true north, magnetic declination, prismatic compass, back bearing (add/subtract 180°), triangulation and resection for locating a point.

Field measurement: girth at breast height (GBH at 1.37 m), diameter tape, height measurement (clinometer, hypsometer, similar triangles), basal area = πr², tree volume using form factor.

Sampling designs: random, systematic, stratified, cluster; quadrat method for vegetation - nested quadrats for trees, shrubs, herbs; line transect and belt transect for wildlife.

Vegetation analysis formulae: density = individuals/area; frequency = quadrats with species/total quadrats × 100; abundance = individuals/frequency quadrats; IVI = relative density + relative frequency + relative dominance.

Herbarium and specimen preparation: collection, pressing, drying, mounting, labelling (scientific name, family, locality, date, collector); use of floras and dichotomous keys for identification.

Soil and water field tests: soil texture by feel and sedimentation (hydrometer), pH by pH paper/colorimeter, organic matter by ignition, infiltration by double-ring infiltrometer; water pH, DO, turbidity.

GPS and GIS basics: waypoints, latitude/longitude (WGS84), map layers, remote sensing (NDVI for vegetation), ground truthing; safety and ethics in field surveys including prior informed consent.