NEET Biology Ecological Succession Multiple Choice Question And Answers

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Biology MCQ For NEET With Answers Ecological Succession

Question 1. The natural process by which different groups or communities colonize the same area over a period of time in a definite sequence is called

  1. Adaptation
  2. Variation
  3. Succession
  4. Biological rhythm

Answer: 3. Succession

Succession is the natural process by which different groups or communities colonize the same area over a period of time in a definite sequence.

Question 2. During ecological succession 

  1. The Number And Types Of Animals Remain Constant
  2. The Changes Lead To A Community That Is In Near Equilibrium With The Environment And Is Called Pioneer Community
  3. The Gradual And Predictable Change In Species Composition Occurs In A Given Area
  4. The establishment of a new biotic community is very fast in its primary phase

Answer: 3. The Gradual And Predictable Change In Species Composition Occurs In A Given Area

ecological succession class 12

The sequential, gradual and predictable changes in the species composition in an area are called ecological succession.

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Question 3. Ecological succession is

  1. A Long Term Process
  2. A Very Fast Process
  3. A Short Term Process
  4. Also known as migration

Answer: 1. A Long Term Process

Ecological succession is directional because succession proceeds in a direction and is a long term process.

Question 4. What is represented by this sequence? Cyanobacteria → Crustose lichens → Foliose lichens → Mosses → Shrubs → Dicotyledonous plants

  1. Genetic drift
  2. Eltonian pyramid
  3. Ecological succession
  4. Phylogenetic relationships

Answer: 3. Ecological succession

The given sequence represents ecological succession. There is change in the species structure of an ecological community over time.

Mcq On Ecological Succession

NEET Biology Ecological Succession Multiple Choice Question And Answers

Question 5. Succession showing changes in communities at a place is called 

  1. Geographical Succession
  2. Biotic Succession
  3. Physiographic Succession
  4. Climatic succession

Answer: 2. Biotic Succession

ecological succession class 12

Communities are never stable, but keep on changing. This relatively definite sequence of communities over a period of time in the same area is called ecological or biotic succession.

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Question 6. Biotic succession is caused by

  1. Competition Amongst Species
  2. Occurrence Of Diseases
  3. Changes Is Grazing Habits
  4. Adaptive ability to environmental changes

Answer: 4. Adaptive ability to environmental changes

Biotic succession is caused by adaptive ability of a species to environmental changes.

Question 7. Succession occurs in

  1. Plant
  2. Animal
  3. Both 1 and 2
  4. None of the above

Answer: 3. Both 1 and 2

Succession can occur in both plant and animals.

Question 8. Plant succession is a ……………… process.

  1. Definite
  2. Haphazard
  3. Unimportant
  4. Orderly

Answer: 4. Orderly

Plant succession is an orderly process of community change in an area over a period of time.

Mcq On Ecological Succession

Question 9. ……….. can be defined as the entire sequence of communities that successively change in a given area.

  1. Sere
  2. Climax
  3. Pioneer species
  4. Xerarch

Answer: 1. Sere

The entire sequence of development stage of biotic succession from pioneer to a climax community is known as sere.

Question 10. Ecesis is

  1. Establishment Of A Plant In A New Place
  2. A Condition Of Equilibrium
  3. Climax
  4. Invasion of a number of plants

Answer: 1. Establishment Of A Plant In A New Place

Ecesis is the process by which a plant or animal becomes established in a new habitat.

Question 11. The process by which a bare area is created is

  1. Invasion
  2. Nudation
  3. Reaction
  4. Coaction

Answer: 2. Nudation

Nudation is the process by which bare area is created. Processes that might lead to nudation are land slides volcanic eruptions, forest fire, agriculture, etc.

Question 12. The correct sequence of events during ecological succession is

  1. Nudation, Invasion, Reaction, Stabilisation
  2. Invasion, Nudation, Stabilisation, Reaction
  3. Reaction, Invasion, Coaction, Climax
  4. Stabilisation, Reaction, Nudation, Climax

Answer: 1. Nudation, Invasion, Reaction, Stabilisation

The correct sequence of events during ecological succession is nudation, invasion, reaction, stabilisation.

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Question 13. Succession on the secondary bare area is

  1. Primosere
  2. Xerosere
  3. Subsere
  4. None of the above

Answer: 3. Subsere

Subsere is a secondary succession arising after an ecological climax community that has been interrupted or destroyed. (as by fire or human agency).

Mcq On Ecological Succession

Question 14. An individual transitional community in ecological succession are termed as

  1. Climax Community
  2. Pioneer Community
  3. Seral Communities
  4. Single community

Answer: 3. Seral Communities

The various biotic communities that develop during biotic succession are termed as seral or transitional communities.

Question 15. In succession, the seral forms are

  1. Large Sized
  2. Long Lived
  3. Less Diverse
  4. Slow growing

Answer: 3. Less Diverse

A seral community consist of less diverse, short-lived, usually small-sized, and fast-growing species.

Question 16. In autogenic succession

  1. Early And Continued Dominance Of Autotrophic Organisms Takes Place
  2. Replacement Of Existing Communities Caused Largely By Any Other External Condition
  3. Early Dominance Of Heterotrophs Takes Place Such As Bacteria, Fungi And Other Animals
  4. Community Itself Modifies Its Own Environment, Thus Causing Its Own Replacement By New Communities
  5. Starts With Previously Built Up Substrata With Already Existing matter

Answer: 4. Community Itself Modifies Its Own Environment, Thus Causing Its Own Replacement By New Communities

Autogenic succession (auto-self, genic–generate) is the modification and the development of new environment made by the community itself such that the community makes its own replacement by new communities. The changed environment is favourable for new community.

Question 17. The species that invade a bare area in ecological succession are called

  1. Benthos
  2. Founding Species
  3. Seral Species
  4. Pioneer species

Answer: 4. Pioneer species

The first biotic community which develops in a bare area and start succession is called pioneer community or species. It has very little diversity. This stage takes the longest time to change the environment for invasion by the next community

Mcq On Ecological Succession

Question 18. A community which starts succession in a habitat is 

  1. Pioneer Community
  2. Seral Community
  3. Biotic Community
  4. Ecosere

Answer: 1. Pioneer Community

The first biotic community which develops in a bare area and start succession is called pioneer community or species. It has very little diversity. This stage takes the longest time to change the environment for invasion by the next community

Question 19. The sequence of successional stages that occur on sand is known as

  1. Lithosere
  2. Hydrosere
  3. Psammosere
  4. Xerosere

Answer: 3. Psammosere

A psammosere ecological succession began life on newly exposed coastal sand. Most common psammoseres are sand dune systems.

Question 20. Primary succession is the development of communities on

  1. Cleared Forest Area
  2. Previously Unoccupied Sites
  3. Fresh Harvested Crop Field
  4. Pond filled after a day season

Answer: 2. Previously Unoccupied Sites

The primary succession occurs in the barren, soilless, previously unoccupied site such as igneous rock emerged from the sea, lava deposit, sand dune, newly created pond or reservoir.

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Question 21. The communities of primary succession are called as

  1. Sub-Sere
  2. Mesosere
  3. Pioneer Sere
  4. None of the above

Answer: 3. Pioneer Sere

The communities of primary succession are called as pioneer sere.

Question 22. Serule is

  1. Hydrosere
  2. Biosphere
  3. Microbial Succession
  4. Lithosere

Answer: 3. Microbial Succession

A succession of microorganisms like fungi, bacteria, etc., occurring within a microhabitat is known as micro succession or rule. This type of succession occurs within communities. For example, in dead trees, animal droppings, etc.

Question 23. Secondary succession is uncomplicated and fast as

  1. The Area Already Has Soil And Some Vegetation
  2. The Area Is Soilless
  3. The Area Is Barren With No Animals Too
  4. None of the above

Answer: 1. The Area Already Has Soil And Some Vegetation

The secondary succession is easy and completed quickly because the area already has soil and some vegetation. Soil is already present in the area, where secondary succession begins.

Question 24. Secondary succession starts in an area

  1. Where No Living Organisms Ever Existed
  2. Which Has Lost All The Living Organisms Once Existed
  3. Where Only One Species Of Organism Existed
  4. Where Human Beings Live

Answer: 2. Which Has Lost All The Living Organisms Once Existed

Secondary succession starts in an area that has lost all the living organisms once existed.

Question 25. Which one of the following statements is incorrect about secondary succession?

  1. It occurs in an area, which has been renewed recently
  2. Soil is present at the time of the beginning of secondary succession
  3. Reproductive structures of the previous occupants are present in the area
  4. It begins on a bare rock

Answer: 4. It begins on a bare rock

The statement in option is incorrect and can be corrected as Secondary succession begins in areas where natural biotic communities have been destroyed, e.g. abandoned farm lands, buried or cut forests (deforested site). Since soil is available, it is a faster process. Primary succession begins in areas where no living organisms ever existed, e.g. bare rock.

Ecological Succession Mcq

Question 26. Which one of the following statements is correct for secondary succession?

  1. It begins on a bare rock
  2. It occurs on a deforested site
  3. It follows a primary succession
  4. It is similar to primary succession except that it has a relatively fast pace

Answer: 2. It occurs on a deforested site

Secondary succession begins in areas where natural biotic communities have been destroyed, e.g. abandoned farmlands, buried or cut forests (deforested site). Since soil is available, it is a faster process. Primary succession begins in areas where no living organisms ever existed, e.g. bare rock.

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Question 27. Primary succession takes much longer than secondary succession because it involves

  1. Development Of The Soil
  2. Development Of A Seed Bank
  3. Colonization By Organisms That Are Farther Away
  4. Colonization by more K-selected organisms

Answer: 1. Development Of The Soil

Primary succession is a biotic succession that occurs on a sterile or bare area unlike secondary succession. Thus, it take longer time to develop as there also occurs development of soil.

Question 28. Which of the following would appear as the pioneer organisms on bare rocks?

  1. Lichens
  2. Liverworts
  3. Mosses
  4. Green algae

Answer: 3. Mosses

Lichens are pioneer organisms on bare rocks as they corrode the rocks by secreting enzymes and convert it into soil.

Question 29. In any lithosere, the pioneer community is

  1. Blue-Green Algae
  2. Foliose Lichens
  3. Mosses
  4. Crustose lichen

Answer: 4. Crustose lichen

Primary succession on rocks or lithosere starts with crustose lichen species like Rhizocarpon, Rinodina, and Lecanora. They produce some acids which bring about weathering of rocks. These lichens are then replaced by foliose type of lichens. Due to deep depressions and retention of water by them, they form a fine thin soil layer on the rock surface and thus, there is a change in the habitat.

Question 30. The pioneer species in xerarch and hydrarch succession are, respectively 

  1. Lichens And Phytoplanktons
  2. Lichens And Sedges
  3. Phytoplanktons And Lichens
  4. Lichens and rooted hydrophytes

Answer: 1. Lichens And Phytoplanktons

The species that invade a bare area are called pioneer species. In xerarch, i.e. succession in dry areas, lichens are pioneer species. In primary succession in water, i.e. hydrarch, the pioneers are the small phytoplanktons.

Ecological Succession Mcq

Question 31. The first plants to reappear in a badly burned forest area will most probably be

  1. Mosses
  2. Liverworts
  3. Ferns
  4. Grasses

Answer: 3. Ferns

Ferns are the first plants to grow after a forest fire as it is a soilbinder. This means ferns, especially the Bracken fern, can withstand a fire or other extremes by gripping the soil with a vast network of roots.

Question 32. The succession includes in series

  1. Lichens → Mosses → Shrubs
  2. Lichens → Mosses → Trees
  3. Mosses → Trees → Shrubs
  4. Mosses → lichens → trees

Answer: 1. Lichens → Mosses → Shrubs

The succession that includes in serie is Lichens → mosses → shrubs

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Question 33. Which one of the following is correct for xerarch succession?

  1. Successional series from xeric to mesic condition
  2. Successional series from hydric to mesic condition
  3. Both 1 and 2
  4. None of the above

Answer: 1. Successional series from xeric to mesic condition

Xerarch succession is plant succession which takes place in dryarea leading to a successional series from xeric to mesic conditions.

Question 34. In which of the following will succession time be least?

  1. Newly created reservoir
  2. Bare rock
  3. Buried or cut forest
  4. Newly cooled lava

Answer: 1. Newly created reservoir

Buried or cut forest already has soil, humus and some vegetation (underground stems). Hence, in buried or cut forest, succession is easy and fast.

Question 35. Xerarch succession is observed in

  1. Desert Areas
  2. Terrestrial Areas
  3. Aquatic Areas
  4. Marshy areas

Answer: 4. Marshy areas

A xerosere is the series of development stages of biotic succession taking place in an arid area like desert area.

Question 36. What role does acid secreted by pioneer species on a barren rock play?

  1. It helps in dissolving rocks.
  2. It helps in weathering.
  3. It helps in soil formation.

Which of the statements given above are correct?

  1. 1 and 2
  2. 1 and 3
  3. 2 and 3
  4. 1, 2 and 3

Answer: 4. 1, 2 and 3

All given statements are correct.

Ecological Succession Mcq

Question 37. Assertion A lake can undergo ecological succession and become a forest over time. Reason (R) A bare rock can become a forest through ecological succession.

  1. Both A and R are true and R is the correct explanation of A
  2. Both A and R are true, but R is not the correct explanation of A
  3. A is true, but R is false
  4. Both A and R are false

Answer: 2. Both A and R are true, but R is not the correct explanation of A

Both A and R are true, but R is not the correct explanation of A. Ecological succession means the natural development of a series of biotic communities, one after the other, in some area till a permanent climax community is established. A lake can become a dryland forest through ecological succession. Ecological succession can turn a bare rock into a forest with time.

Question 38. The final stable community in an ecological succession is 

  1. Pioneers
  2. Sere
  3. Climax
  4. Carnivore

Answer: 3. Climax

The climax community is the stable, self-perpetuating and final biotic community that develops at the end of biotic succession and is in perfect harmony with the physical environment.

Question 39. Climax community found in a large restricted land body is known as

  1. Biogeographic Realms Dpmt
  2. Biome
  3. Savannah
  4. None of the above

Answer: 3. Savannah

The climax community in a large restricted land body is known as savannah.

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Question 40. The nature of climax community ultimately depends on

  1. Climate Cbse Aipmt
  2. Bed Rock
  3. Soil Organisms
  4. Pool of available nutrients

Answer: 1. Climate Cbse Aipmt

The climax community is in harmony with the climate of the region and thus, the nature of this community depend upon available climatic conditions only.

Question 41. All the characteristics are true for climax community except that

  1. It Rapidly Keeps On Changing To Reach Equilibrium
  2. It Is The Final Community
  3. It Is The End Of Succession
  4. It is stable

Answer: 1. It Rapidly Keeps On Changing To Reach Equilibrium

All are characteristics for climax community are true except option as Climax community is stable and is in equilibrium with the environment. Thus, it does not change further to any other form.

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Question 42. In plant succession, when climax community is reached, the net productivity

  1. Continues To Increase
  2. Becomes Zero
  3. Become Reduced
  4. Becomes stable

Answer: 4. Becomes stable

The climax community remains in perfect harmony with the physical environment and has a stable net productivity, maximum diversity and niche specialization.

Question 43. Climax community is

  1. Self-Perpetuating
  2. Final Biotic Community
  3. Stable
  4. All of the above

Answer: 4. All of the above

Climax community is the stable, self-perpetuating, and final biotic community.

Question 44. In ecological succession from pioneer to climax community, the biomass shall 

  1. Decrease
  2. Increase And Then Decrease
  3. No Relation
  4. Increase continuously

Answer: 4. Increase continuously

In ecological succession from pioneer to climax community, the biomass shall increase continuously because after climax communities are made, the species become stable and do not change very much

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Question 45. In ecological succession, the climax community is best recognized by the following state 

  1. P = R
  2. P > R
  3. P < R
  4. P ≠ R

Answer: 1. P = R

The climax community is the final community that develops in an area during ecological succession. In the climax community, productivity and respiration are equal. P = R

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Question 46. Climax vegetation of a region is generally

  1. Xerophytic
  2. Hydrophytic
  3. Mesophytic
  4. Depends upon the climate

Answer: 3. Mesophytic

Mesophytes are terrestrial plants that are neither adapted to particularly dry nor particularly wet environments. These form climax vegetation.

Question 47. Plagioclimax is the climax of plagiosere which means

  1. Sere Of Marine Plants
  2. Deflected Sere Resulting In Deviation Of Plant Succession From Natural Course Due To Human Activity
  3. Sere where plant succession deviates from its natural course due to human activity
  4. Both 2 and 3

Answer: 4. Both 2 and 3

A plagioclimax community is an area or habitat in which the influences of human have prevented the ecosystem from developing further. The ecosystem may have been stopped from reaching its full natural climatic climax or deflected towards a different climax by human activities such as cutting down the existing vegetation.

Question 48. Assertion Every biological system resists change and wants to remain in a state of equilibrium. Reason (R) Climax communities of an ecosystem are produced after several changes it has gone through succession.

  1. Both A and R are true and R is the correct explanation of A
  2. Both A and R are true, but R is not the correct explanation of A
  3. A is true, but R is false
  4. Both A and R are false

Answer: 2. Both A and R are true, but R is not the correct explanation of A

Both A and R are true, but R is not the correct explanation of A. Homeostasis is the tendency of a biological system to maintain relatively constant conditions in the internal environment, while continuously interacting with and adjusting to changes originating within or outside the system. In ecology, a climax community is a biological community of plants, animals and fungi which had reached a steady state. This equilibrium was thought to occur because the climax community is composed of species best adapted to average conditions in that area.

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Question 49. Identify the changes that occur in successive seral stages in order to reach climax.

  1. Changes in the diversity of species of organisms.
  2. Increase in the number of species and organisms.
  3. Increase in the total biomass.

Choose the correct option.

  1. Only 1
  2. Only 2
  3. Only 3
  4. 1, 2 and 3

Answer: 4. 1, 2 and 3

All given statements represent events that occur in successive seral stages in order to reach climax. In successive seral stages, there is not only a change in the species diversity of organisms present, but there is also an increase in the number of species. A succession of plant and animal communities occurs side by side. These also occurs an increase in biomass.

Question 50. Phytoplanktons in the hydrosere constitute

  1. Members Of Climax Community
  2. Pioneer Community
  3. Intermediate Seral Members
  4. All of the above

Answer: 2. Pioneer Community

The passively floating and drifting plants (phytoplanktons) are the pioneers in a hydrosere. They generally comprise green algae, blue algae, diatoms, etc.

Question 51. Match the following columns.

Ecological Succession Match the following columns

Answer: 3. 1 2 4 3

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Question 52. The second stage of hydrosere is occupied by the plants like

  1. Salix
  2. Vallisneria
  3. Azolla
  4. Typha

Answer: 2. Vallisneria

The second stage of hydrosere is occupied by submerged aquatic plants, e.g. Hydrilla, and Vallisneria. The third stage has free-floating plants, e.g. Azolla (floating aquatic fern). The fourth stage is reed swamp which includes indude plants like Typha, Salix Deciduous trees and shrubs, constitute the sixth (woodland stage) and climax stages.

Question 53. Ecological succession in hydrosere includes

  1. Increase In Species Diversity
  2. Increase In Structural Complexity
  3. Increase in organic matter
  4. All of the above

Answer: 4. All of the above

ecological succession class 12

Ecological succession in hydrosere includes increase in species diversity, structural complexity and organic matter.

Question 54. Match the following columns.

Ecological Succession Match the following columns 2

Answer: 3. 1 2 3 4

Question 55. Pick out the correct option from (1) to (4).

  1. Primary succession begins in areas where natural communities have been destroyed.
  2. Hydrarch succession takes place in water.
  3. The climax community is the community that is in near equilibrium with the immediate environment.
  4. In newly cooled lava, secondary succession occurs.

Choose The Correct Option:

  1. 1 and 2 are correct, 3 and 4 are incorrect
  2. 2 and 3 are correct, 1 and 4 are incorrect
  3. 1 and 4 are correct, 2 and 3 are incorrect
  4. 2 only is correct, 1, 3 and 4 are incorrect
  5. Only 1 is correct, 2, 3 and 4 are incorrect

Answer: 2. 2 and 3 are correct, 1 and 4 are incorrect

Statements 2 and 3 are correct, but 1 and 4 are incorrect. These can be corrected as Primary succession occurs on previously bare or unoccupied area, e.g. igneous rocks, sand dunes, newly cooled lava or deltas. In primary succession, environment is very hostile for pioneer community and reproductive structures of any previous community are absent. Secondary succession occurs in an area from which community has been removed and where nutrients and conditions for existence are present, e.g. cut over forest, ploughed fields and abandoned crop land.

Question 56. Fill up the blanks.

  1. Pioneer species on bare rocks – A
  2. Secretions that help in dissolving rocks and enabling soil formation – B
  3. First species to appear – C
  4. Community that has undergone continuous change to attain stability – D
  5. Pioneers in primary succession in water – E

ecological succession class 12

Choose The Correct Option:

  1. A–Bryophytes, B–Acid, C–Climax community, D–Pioneer community, E–Zooplanktons
  2. A–Lichen, B–Acid C–Pioneer species, D–Climax community, E–Passively floating phytoplanktons
  3. A–Lichen, B–Base, C–Xerosere, D–Seral stages, E–Small plant
  4. A–Lichen, B–Acid, C–Pioneer species, D–Climax community, E–Submerged floating plants

Answer: 2. A–Lichen, B–Acid C–Pioneer species, D–Climax community, E–Passively floating phytoplanktons

Question 57. Identify the plant belonging to the reed-swamp stage in hydrarch succession.

  1. Juncus
  2. Sagittaria
  3. Salix
  4. Trapa

Answer: 2. Sagittaria

Reed-swamp stage is also known as amphibious stage as the plants are rooted, but most parts of their shoots (assimilatory organs) remain exposed to air and possess emergent leaves.Scirpus, Typha, Sagittaria and Phramites, etc., are the chief plants of this stage. They have well-developed rhizomes and form a very dense vegetation.

Question 58. The areas, where water is present in abundance is called

  1. Hydrarch Succession
  2. Xerarch Succession
  3. Hydrosere
  4. Both 1 and 2

Answer: 4. Both 1 and 3

Hydrarch succession occurs in wet areas or water and the successional series progress from hydric to the mesic conditions. A hydrosere is a plant succession which occurs in an area of freshwater such as in Oxbow lakes and Kettle lakes. Xerarch succession takes place in dry areas and the series progress from xeric to mesic conditions. So, option is correct.

Question 59. Both hydrarch and xerarch successions lead to CBSE AIPMT

  1. Medium Water Conditions
  2. Xeric Conditions
  3. Highly Dry Conditions
  4. Excessive wet conditions

Answer: 1. Medium Water Conditions

Hydrarch succession takes place in wetter areas and the succession series progress from hydric to the mesic condition. Xerarch succession takes place in dry areas and the series progress from xeric to mesic condition. Hence, both hydrarch and xerarch succession leads to medium water conditions (mesic).

Question 60. Consider the following statements on succession of plants.

  1. In hydrarch succession progress is observed from hydric to the mesic condition.
  2. In xerarch succession progress is observed from xeric to the mesic condition.
  3. Xerarch succession if started on bare rock, pioneer species is lichens.
  4. In hydrarch and xerarch succession, progress is observed from mesarch to xerarch condition.

Choose option containing correct statements.

  1. 1 and 3
  2. 3 and 4
  3. 2 and 4
  4. 1, 2 and 3

Answer: 4. 1, 2 and 3

All statements are correct except IV. It can be corrected as Both hydrarch and xerarch succession ultimately lead to mesarch conditions. The pioneer species on bare rock is always lichen.

Question 61. The correct sequence of plants in a hydrosere is CBSE PMT

  1. Volvox → Hydrilla → Pistia → Scirpus → Lantana → Oak
  2. Pistia → Volvox → Scirpus → Hydrilla → Oak → Lantana
  3. Oak → Lantana → Volvox → Hydrilla → Pistia → Scirpus
  4. Oak → Lantana → Scirpus → Pistia → Hydrilla → Volvox

Answer: 1. Volvox → Hydrilla → Pistia → Scirpus → Lantana → Oak

The correct sequence of plants in a hydrosere is Volvox, Hydrilla, Pistia, Scirpus, Lantana and Oak. A hydrosere is a plant succession which occurs in a freshwater lake. In time, an area of open freshwater such as a lake naturally dry out and ultimately become woodland. During this change, a range of different land types such as swamp and marsh succeed each other. The succession from open water to climax woodland is likely to take at least two hundred years.

ecological succession class 12

Question 62. What is observed in hydrarch succession?

  1. Growth of phytoplanktons followed by submerged and free-floating plants, rooted hydrophytes, sedges, grasses and trees
  2. Transformation of pool of water to swamp and then to marsh and mesic condition
  3. Growth of lichens and weathering of rocks
  4. Both 1 and 2

Answer: 4. Both 1 and 2

  • Hydrarch succession occurs in the following steps
  • Phytoplankton stage Spores, algae, and bacteria enter the water body which multiply and flourish to form phytoplanktons (Pioneer species).
  • Submerged stage Submerged hydrophytes like Vallisneria, utricularia grow.
  • Floating stage Plants like Nymphaea, Typha, etc., grow in this stage.
  • Reed swamp stage Amphibious plants like Marsilea, Polygonum grow, depth of water body decreases.
  • Sedge grass stege Marshy soil is formed due to decreased water level. Plants like Carex, Iris, etc.,grow in this stage.
  • Shrub stage Mesic conditions are created which allow the growth of Salix, Cassia, etc.

Question 63. Given below are several sequences of primary successions in water or hydrosere. Choose the correct sequence.

  1. Small phytoplanktons → Free-floating angiosperms → Rooted hydrophytes → Sedges → Grasses → Trees
  2. Free-floating angiosperm → Rooted hydrophytes → Small phytoplanktons → Grasses → Sedges → Trees
  3. Small phytoplanktons → Sedges → Free-floating angiosperms → Rooted hydrophytes → Grasses → Trees
  4. Small phytoplanktons → Zooplankton → Grasses → Freefloating angiosperms → Rooted hydrophytes → Trees

Answer: 1. Small phytoplanktons → Free-floating angiosperms → Rooted hydrophytes → Sedges → Grasses → Trees

The correct sequence is Small phytoplanktons → Free floating angiosperms → Rooted hydrophytes → Sedges → Grasses → Trees.

Question 64. Find out the correct order of succession levels in xerarch or rock.

  1. Lichen → moss stage → annual herb stage → perennial herb stage and shrub stage → forest
  2. Annual herb stage → perennial herb stage → lichen → moss stage → shrub stage → forest
  3. Shrub stage → forest annual herb stage → perennial herb stage → lichen → moss stage
  4. Forest → shrub stage → annual herb stage → perennial herb stage → lichen → moss stage

Answer: 1. Lichen → moss stage → annual herb stage → perennial herb stage and shrub stage → forest

ecological succession class 12

Succession levels in xerarch (serosere/lithosere) are:

  1. Lichen stage, e.g. crustose lichens followed by foliose lichens.
  2. Moss stage, e.g. Tortula, Polytrichum.
  3. Annual herb stage, e.g. Cymbopogon.
  4. Perennial herb and shrub stage, e.g. Rubus, Capparis, Zizyphus.

Climax community, e.g. forest with herbs shrubs, and trees.

Question 65. Find out the wrong sequence.

  1. Phytoplanktons → submerged plants → free-floating plants → rooted hydrophytes
  2. Lichens → trees → shrubs → herbs
  3. The pool of water → swamp → marsh → Mesic conditions
  4. Sedges → grasses → woodland → forest

Answer: 2. Lichens → trees → shrubs → herbs

The option is showing the wrong sequence. It can be corrected as Lichens → Herbs → Shrubs → Trees

Question 66. Match the following columns.

Ecological Succession Match the following columns 1

Answer: 1. 4 1 2 3

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