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12th Standard Biology English Medium Ecosystem Reduced Syllabus Important Questions With Answer Key 2021

12th Standard

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Biology

Time : 01:00:00 Hrs
Total Marks : 100

    Multiple Choice Questions

    15 x 1 = 15
  1. Which of the following is / are not a natural ecosystem?

    (a)

    Forest ecosystem

    (b)

    Rice field

    (c)

    Grassland ecosystem

    (d)

    Desert ecosystem

  2. Which of the following ecosystem has the highest primary productivity?

    (a)

    Pond ecosystem

    (b)

    Lake ecosystem

    (c)

    Grassland ecosystem

    (d)

    Forest ecosystem

  3. Which one is in descending order of a food chain

    (a)

    Producers \(\rightarrow \) Secondary consumers \(\rightarrow \) Primary consumers \(\rightarrow \) Tertiary consumers

    (b)

    Tertiary consumers \(\rightarrow \) Primary consumers \(\rightarrow \)Secondary consumers \(\rightarrow \) Producers

    (c)

    Tertiary consumers \(\rightarrow \) Secondary consumers \(\rightarrow \) Primary consumers \(\rightarrow \) Producers

    (d)

    Tertiary consumers \(\rightarrow \) Producers \(\rightarrow \) Primary consumers \(\rightarrow \) Secondary consumers

  4. Significance of food web is / are

    (a)

    it does not maintain stability in nature

    (b)

    it shows patterns of energy transfer

    (c)

    it explains species interaction

    (d)

    b and c

  5. Which of the following is not a sedimentary cycle

    (a)

    Nitrogen cycle

    (b)

    Phosphorous cycle

    (c)

    Sulphur cycle

    (d)

    Calcium cycle

  6. Identify the incorrect option among the following component sequence.

    (a)

    air, water, sunlight and temperature

    (b)

    latitude, altitude, direction of mountain and aptitude

    (c)

    soil air, pH of soil, saltwater and soil moisture

    (d)

    carbohydrate, protein, lipids and humic substances

  7. Photosynthetically Active Radiation ranges between the wavelength of __________

    (a)

    400 - 600 nm

    (b)

    600 - 700 nm

    (c)

    400 - 500 nm

    (d)

    400 - 700 nm

  8. Which group of organism occupies the third tropic level in an ecosystem?

    (a)

    Primary consumers

    (b)

    Secondary consumers

    (c)

    Secondary carnivores

    (d)

    Omnivores

  9. Which of the following food chain is in improper sequence?

    (a)

    Plants ~ snake ~ rabbit ~ lizard ~ eagle

    (b)

    Plants ~ grasshopper ~ lizard ~ snake ~ hawk

    (c)

    Plants ~ lizard ~ rabbit ~ snake ~ eagle

    (d)

    Plants ~ rabbit ~ lizard ~ hawk ~ eagle

  10. Pyramid of numbers with broad base indicates ______

    (a)

    High population of old individuals

    (b)

    Low population of young individuals

    (c)

    High population of young individuals

    (d)

    Low population of old individuals

  11. Complete the food chain by filling the link X:
    Paddy ~ Grassopper ~ Frog ~ X ~ Hawk

    (a)

    King cobra

    (b)

    Gorilla

    (c)

    Rabbit

    (d)

    Tasmanial wolf

  12. Which type of ecosystem service does the genetic resources comes under?

    (a)

    Provisioning services

    (b)

    Supporting services

    (c)

    Regulating services

    (d)

    Cultural services

  13. Assertion (A): In forest ecosystem, the pyramid of number is spindle shaped.
    Reason (R): Tropical level (Tl) of the pyramid occupies large trees which are maxium in
    number.

    (a)

    Both A and R are wrong

    (b)

    A is right R is wrong

    (c)

    R explains A

    (d)

    A is right R is not the correct explanation for A

  14. Succession initiating on a sand referred as

    (a)

    Hydrosere

    (b)

    Psammosere

    (c)

    Halosere

    (d)

    Lithosere

  15. Statement (I): The first invaded plants in a barren area are called as pioneers.
    Statement (II): Marsh meadow stage of hydro sere succession is also called as amphibious stage.

    (a)

    Statement I is correct; Statement II is incorrect.

    (b)

    Statement I is incorrect; Statement II is correct.

    (c)

    Both Statements I and II are correct.

    (d)

    Both Statements I and II are incorrect.

  16. 2 Marks

    10 x 2 = 20
  17. Productivity of profundal zone will be low. Why?

  18. What will happen if all producers are removed from ecosystem?

  19. Mention any two climatic factors and edaphic factors of an ecosystem.

  20. What is meant by productivity of an ecosystem?

  21. State the role of herbivores and microconsumers in a terrestrial ecosystem.

  22. Which is the first link in a grazing food chain and a detritus food chain?

  23. Why do we obtain an inverted pyramid in a parasite ecosystem?

  24. Biogeochemical cycle comprises both gaseous cycle and sedimentary cycle. How they differ from one another?

  25. What is meant by Ecosystem resilience?

  26. Which kind of organisms constitute the pioneer community and climax community of a Hydrosere succession?

  27. 3 Marks

    10 x 3 = 30
  28. Shape of pyramid in a particular ecosystem is always different in shape. Explain with example.

  29. Generally human activities are against to the ecosystem, where as you a student how will you help to protect ecosystem?

  30. List the factors affecting primary productivity.

  31. Give an account on the concept of trophic level in an ecosystem.

  32. Write a brief note on Detritus food chain.

  33. Spindle shaped pyramid of number is noticed in forest ecosystem. Give reasons.

  34. What is biogeochemical cycle? Explain its types.

  35. Explain the cycling of phosphorus in an ecosystem.

  36. Point out any three mangrove ecosystem services.

  37. Mention any two vital biomolecules that requires phosphorous for their biosynthesis.

  38. 5 Marks

    7 x 5 = 35
  39. Generally in summer the forest are affected by natural fire. Over a period of time it recovers itself by the process of successions .Find out the types of succession and explain.

  40. Draw a pyramid from following details and explain in brief.
    Quantities of organisms are given-Hawks-50, plants-1000.rabbit and mouse-250 +250, pythons and lizard- 100 + 50 respectively.

  41. Various stages of succession are given bellow. From that rearrange them accordingly. Find out the type of succession and explain in detail.
    Reed-swamp stage, phytoplankton stage, shrub stage, submerged plant stage, forest stage, submerged free floating stage, marsh medow stage.

  42. What are the strategies of eco system management?

  43. Differentiate Primary succession and Secondary succession.

  44. Write in detail about Autogenic succession and Allogenic succession.

  45. What are the significance of plant succession?

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