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Ecology Basics: asked and not asked.

UPSC has asked 15 of these 23. 5 came more than once. 8 have not come yet. Lock the repeated ones first, then read the rest.

First, the concept

Energy flows one way through an ecosystem, from the Sun to producers to consumers, and is lost as heat at each step. Nutrients go round in cycles.

Only about 10 percent of the energy passes from one level to the next (Lindeman's 10 percent law). That is why food chains are short and the pyramid of energy is never upside down.

UPPCS asks the definitions and the exceptions: which pyramid can be inverted, which species is the pioneer, what an ecotone is.

🔁 Asked again and again (5)

Tap a year to open that solved question.

Words and their makers

Food chains and pyramids

  • Primary productivity · Gross is all food made by plants; net is what is left after their own respiration 9 times:202620262023201320112003

Change over time

  • Ecological succession · Slow, orderly change in a community till it reaches a stable climax 3 times:201319861986
  • Pioneer species · First to settle on bare rock: lichens 3 times:199119911991

Edges, species roles and limits

  • Ecological footprint and Earth Overshoot Day · The land and sea a person needs; the day each year we use up a year's resources 4 times:2021202020202009

✅ Asked once (10)

Words and their makers

  • Ecology (Haeckel) · The word was coined by Ernst Haeckel (1869)
  • Ecological niche · The role and position of a species in its habitat 2013
  • Biome · A large region with its own climate, plants and animals: desert, tundra, rain forest 2021

Food chains and pyramids

  • 10 percent law · Lindeman (1942); energy passed to the next level
  • Pyramid of biomass · Inverted in the sea (phytoplankton weigh less than the fish)

Edges, species roles and limits

  • Ecotone · The meeting zone of two ecosystems, like a mangrove between land and sea 2013
  • Indicator species · Shows the health of the environment: lichens for sulphur dioxide 2008
  • Biomagnification · A poison like DDT or mercury grows stronger up the food chain 2010
  • Keystone species · A species whose loss changes the whole ecosystem (tiger, fig, sea otter) 2000
  • Carrying capacity · The largest population an area can support for long 2010

❌ Not asked by UPSC yet (8)

Items marked 'asked in UPPCS' have already come in the UP state exam, so examiners do use them.

Food chains and pyramids

  • Grazing and detritus food chains · Grazing starts from green plants; detritus starts from dead matter asked in UPPCS
  • Food web · Many food chains joined together; makes the ecosystem stable
  • Pyramid of numbers · Inverted in a tree ecosystem (one tree, many insects)
  • Pyramid of energy · Always upright, never inverted

Change over time

  • Climax community · The final, stable stage of succession asked in UPPCS
  • Hydrosere and xerosere · Succession starting in water; starting on dry rock

Edges, species roles and limits

  • Edge effect · More species live in the ecotone than in either side
  • Flagship species · A popular animal used to win support for conservation (tiger, panda)

⚠️ The pyramid of energy is never inverted; the pyramids of numbers and biomass can be. Lichens are the pioneers on rock, not mosses.

'Asked' is checked against the solved UPSC questions on this site. 'Not asked yet' does not mean it will surely come.

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