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Zoology · Class 11 Science

Ch 8Ecology and Environment — Class 11 Zoology, concept-first.

Ecology is the branch of biology that studies how living organisms relate to one another and to their surroundings. Unlike physiology, which looks inward at how an organism's own body works, ecology looks outward — at the web of relationships an organism is embedded in.

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Ecology: Definitions, Branches and Hierarchy

Ecology is the study of how organisms interact with each other and with their physical surroundings. It is traditionally split into autecology, which examines a single species in relation to its environment (its toleranc…

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Chapter contents

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Ecology: Definitions, Branches and Hierarchy

Ecology is the branch of biology that studies how living organisms relate to one another and to their surroundings.

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Abiotic Factors

Abiotic factors are the non-living, physical and chemical components of the environment — light, temperature, water, soil, and altitude among them — that constrain and shape the distribution, physiolo…

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Biotic Interactions

Organisms sharing an environment interact with one another in ways that range from mutually beneficial to one-sidedly harmful.

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Ecosystem Structure and Types

An ecosystem is a functional unit made up of a community of organisms (the biotic component) together with the physical environment they live in (the abiotic component), linked by the flow of energy a…

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Energy Flow

Unlike nutrients, which cycle repeatedly through an ecosystem, energy flows through it in one direction only — entering as sunlight, being fixed by producers, and being progressively lost as heat at e…

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Pollution and Conservation

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Human activity has altered the environment on scales ranging from local water bodies to the whole atmosphere.

+Very Short Answer Questions40 questions
  1. Q1What is ecology? Distinguish between autecology and synecology.Free
  2. Q2Arrange the following in the correct ecological hierarchy: community, ecosystem, population, biome.Free
  3. Q3Distinguish between habitat and niche.Free
  4. Q4What is meant by the ecosphere or biosphere?Preview
  5. Q5What is phototaxis?Preview
  6. Q6Distinguish between phototaxis and photokinesis.Preview
  7. Q7What are circadian rhythms?Preview
  8. Q8What is photoperiodism?Preview
  9. Q9What is bioluminescence? Give an example.Preview
  10. Q10Mention two harmful effects of excess UV radiation on organisms.Preview
  11. Q11State van't Hoff's rule.Preview
  12. Q12What is cyclomorphosis? In which organism is it commonly seen?Preview
  13. Q13Define minimum, maximum and optimum effective temperature.Preview
  14. Q14Distinguish between euryhaline and stenohaline animals.Preview
  15. Q15How do marine bony fishes cope with the hypertonic environment of sea water?Preview
  16. Q16How do freshwater animals cope with a hypotonic environment?Preview
  17. Q17Mention any two adaptations of animals living at high altitude.Preview
  18. Q18What is xerokinesis or dehydration adaptation? Give an example.Preview
  19. Q19What is mutualism? Give an example.Preview
  20. Q20Explain the fig-wasp relationship briefly.Preview
  21. Q21What is commensalism? Give an example.Preview
  22. Q22What is amensalism? Give an example.Preview
  23. Q23What is brood parasitism? Give an example.Preview
  24. Q24What is competitive release?Preview
  25. Q25Mention two anti-herbivory defences seen in plants.Preview
  26. Q26Distinguish between lentic and lotic ecosystems.Preview
  27. Q27Name the three zones of a lake ecosystem.Preview
  28. Q28What is thermal stratification in a lake?Preview
  29. Q29Distinguish between marine, freshwater and estuarine ecosystems in one line each.Preview
  30. Q30Distinguish between a grazing food chain (GFC) and a detritus food chain (DFC).Preview
  31. Q31What is a food web?Preview
  32. Q32Name the different types of ecological pyramids.Preview
  33. Q33State the second law of thermodynamics as applied to an ecosystem.Preview
  34. Q34Distinguish between primary productivity and secondary productivity.Preview
  35. Q35What are saprotrophs and detritivores?Preview
  36. Q36What is ozone depletion? Name one gas responsible for it.Preview
  37. Q37What is eutrophication?Preview
  38. Q38What is the greenhouse effect?Preview
  39. Q39What is biological magnification? Give an example.Preview
  40. Q40Mention two causes of groundwater depletion.Preview
+Short Answer Questions24 questions
  1. Q1Explain the different branches of ecology and the levels of the ecological hierarchy with examples.Free
  2. Q2Explain habitat and niche with suitable examples, bringing out how two species can share a habitat but occupy different niches.Free
  3. Q3Describe the role of light as an ecological factor, with reference to phototaxis, photokinesis and biological rhythms.Free
  4. Q4Explain photoperiodism and bioluminescence as light-related adaptations in organisms.Preview
  5. Q5Explain van't Hoff's rule and describe cyclomorphosis in Daphnia as an example of temperature-driven seasonal change.Preview
  6. Q6Describe the osmotic adaptations shown by marine and freshwater animals to their respective environments.Preview
  7. Q7Explain soil as an abiotic factor and describe the adaptations of organisms living at high altitude and in dehydrating conditions.Preview
  8. Q8Explain mutualism and commensalism with suitable examples, bringing out the difference between the two.Preview
  9. Q9Explain parasitism and brood parasitism with examples.Preview
  10. Q10Explain predation and its role in biological control and the maintenance of species diversity.Preview
  11. Q11Explain interspecific competition and competitive release, with reference to Gause's principle.Preview
  12. Q12Explain amensalism and the anti-herbivory defences shown by plants against grazing animals.Preview
  13. Q13Describe the structure and types of aquatic ecosystems.Preview
  14. Q14Describe the zonation of a lake ecosystem and explain thermal stratification in summer and winter.Preview
  15. Q15Describe the general structure and features of terrestrial ecosystems.Preview
  16. Q16Explain the flow of energy through an ecosystem, distinguishing a grazing food chain from a detritus food chain.Preview
  17. Q17Explain food webs and the different types of ecological pyramids with examples.Preview
  18. Q18Explain how the second law of thermodynamics limits energy transfer between trophic levels in an ecosystem.Preview
  19. Q19Distinguish between primary and secondary productivity, and explain the process of decomposition in an ecosystem.Preview
  20. Q20Explain eutrophication and its effect on aquatic ecosystems.Preview
  21. Q21Explain the greenhouse effect and its role in global warming.Preview
  22. Q22Explain the problem of e-waste and the practice of organic farming as approaches related to environmental management.Preview
  23. Q23Explain the sources and effects of noise pollution and radioactive waste.Preview
  24. Q24Explain the role of women and local communities in forest conservation in India, with reference to municipal solid waste management.Preview
+Essay Questions1 question
  1. Q1Write an essay on temperature as an ecological factor.Preview

Sample & Board Papers

Sample papers and previous-year board questions for this subject.

+Show 25 questions25 questions
  1. Q1What is an ecosystem ?Preview
  2. Q2What are the reasons for greater biodiversity in the tropics ?Preview
  3. Q3List out the major air pollutants and describe their effects on human beings.Preview
  4. Q4Write the full form of IUCN. In which book threatened species are enlisted?Preview
  5. Q5Explain "Rivet Popper hypothesis".Preview
  6. Q6Define ecological pyramids and describe with examples pyramids of numbers and biomass.Preview
  7. Q7Describe different types of food chains that exist in an ecosystem.Preview
  8. Q8Mention the advantages of some UV rays to us.Preview
  9. Q9What is genetic diversity? What are the different types of genetic diversity?Preview
  10. Q10What is summer stratification? Explain.Preview
  11. Q11List out the major air pollutants and describe their effects on human beings.Preview
  12. Q12Define species richness.Preview
  13. Q13How do terrestrial animals protect themselves from the danger of desiccation of bodies?Preview
  14. Q14Distinguish between euryhaline and stenohaline animals.Preview
  15. Q15Describe different types of food chains that exist in an ecosystem.Preview
  16. Q16What are the reasons for greater biodiversity in the tropics?Preview
  17. Q17Describe 'Greenhouse Effect'.Preview
  18. Q18Describe different types of food chains that exist in an ecosystem.Preview
  19. Q19What is BOD?Preview
  20. Q20Explain 'Rivet Popper' hypothesis.Preview
  21. Q21Describe 'Green House Effect'.Preview
  22. Q22Describe different types of food chains that exist in an ecosystem.Preview
  23. Q23What is an ecosystem?Preview
  24. Q24What is summer stratification? Explain.Preview
  25. Q25Describe different types of food chains that exist in an ecosystem.Preview