Ecological Succession and Species Diversity

COMPETITIVE EXAM MCQs SERIES of ENVIRONMENTAL SCIENCE for UGC-NET/JRF, SLETARS, GATE, and other entrance tests – Environmental Biology – Ecological Succession and Species Diversity.

Syllabus Outline

  1. Types of ecological succession (e.g. primary and secondary) and the factors influencing it
  2. Distinctions between autogenic and allogenic succession.
  3. The ecological succession stages (e.g. pioneer community, climax community, and intermediate stages).
  4. Mechanisms and drivers of succession (e.g. disturbances, facilitation, inhibition, tolerance, and soil development).
  5. Species richness and ecosystem diversity.
  6. Indices like Shannon-Weaver and Simpson’s.
  7. Patterns and drivers of species diversity (e.g. latitudinal gradients, habitat size, and human impacts).
  8. Threats to ecological succession and species diversity.
  9. Conservation strategies, community engagement, and ecosystem management for sustainable practices.
  10. Research trends and the integration of ecological succession and biodiversity in ecosystem management.

This quiz contains the concept-based most frequently asked 25 MCQs of “Environmental Biology – Ecological Succession and Species Diversity“. Each question has a single correct/most appropriate answer.


1. What distinguishes secondary succession from primary succession?

a) Human intervention

b) Lack of pioneer species

c) Slower rate of change

d) Soil already present

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2. Which hypothesis suggests that biodiversity is influenced by both the rate of immigration and the rate of extinction in a given area?

a) Intermediate Disturbance Hypothesis

b) Island Biogeography Theory

c) Ecological Succession Hypothesis

d) Biotic Interactions Model

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3. What does the term Beta diversity represent?

a) The total number of species in a given area

b) The diversity within a specific habitat or community

c) The genetic diversity within a single species

d) The diversity between different habitats or communities

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4. What is the primary difference between autogenic and allogenic factors influencing ecological succession?

a) Autogenic factors only impact primary succession, while allogenic factors impact secondary succession

b) Autogenic factors involve human activities, while allogenic factors are natural processes

c) Autogenic factors are internal, while allogenic factors are external

d) Autogenic factors are predictable, while allogenic factors are unpredictable

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5. What is the primary factor influencing species diversity in an ecosystem?

a) Soil pH

b) Latitude

c) Altitude

d) Temperature

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6. How does the process of Landscape Fragmentation impact species diversity?

a) It decreases species diversity by promoting connectivity between habitats

b) It increases species diversity by creating isolated habitats

c) It leads to edge effects, affecting species composition

d) It has no impact on species diversity

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7. Which research concept involves studying the interactions between species and their environment over extended periods to understand ecosystem dynamics?

a) Ecosystem modelling

b) Experimental ecology

c) Ecotourism

d) Long-term ecological research

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8. Which factor is crucial in determining the rate of species turnover in an ecosystem?

a) Soil composition

b) Biotic interactions

c) Climate stability

d) Human interference

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9. What is the primary contribution of the Unified Neutral Theory to our understanding of community structure and species diversity?

a) It emphasizes the importance of competition in shaping communities

b) It highlights the role of keystone species in maintaining biodiversity

c) It suggests that species are functionally equivalent, and diversity arises from random processes

d) It focuses on the influence of abiotic factors on community composition

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10. Which of the following is an example of a primary pioneer species in aquatic ecosystems which helps in new land area formation?

a) Phytoplankton

b) Seagrasses

c) Mangroves

d) Water lilies

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11. What is the relationship between the species-area curve and species diversity?

a) The curve indicates a positive correlation

b) The curve shows a negative correlation

c) The curve is unrelated to species diversity

d) The curve only applies to aquatic ecosystems

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12. How does fire contribute to secondary succession in certain ecosystems?

a) It creates a climax community

b) It has no impact on succession

c) It inhibits succession

d) It accelerates succession

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13. Assertion (A): Climax communities in ecological succession remain unchanged over time.

Reason (R): The climax community represents a state of balance between all living organisms and their environment.

a) Both A and R are true, and R is the correct explanation for A.

b) A is true, but R is false.

c) Both A and R are true, but R is not the correct explanation for A.

d) A is false, but R is true.

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14. What is the significance of maintaining high species diversity in ecosystems?

a) It ensures aesthetic appeal for ecotourism

b) It enhances ecosystem resilience and stability

c) It simplifies management efforts for protected areas

d) It accelerates the process of ecological succession

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15. Assertion (A): The species-area curve demonstrates a positive correlation between the size of an area and the number of species it can support.

Reason (R): Larger areas provide more diverse habitats and resources, promoting higher species diversity.

a) Both A and R are true, and R is the correct explanation for A.

b) A is false, but R is true.

c) A is true, but R is false.

d) Both A and R are true, but R is not the correct explanation for A.

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16. What is the primary factor influencing the rate of secondary succession in a disturbed area?

a) Presence of pioneer species

b) Soil fertility

c) Distance from a climax community

d) Availability of light

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17. Assertion (A): Pioneer species in ecological succession often exhibit traits that enable them to colonize harsh environments.

Reason (R): These traits may include tolerance to extreme conditions and the ability to facilitate soil development.

a) A is false, but R is true.

b) A is true, but R is false.

c) Both A and R are true, but R is not the correct explanation for A.

d) Both A and R are true, and R is the correct explanation for A.

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18. Which type of biodiversity is often considered the most crucial for ecosystem stability?

a) Genetic diversity

b) Ecosystem diversity

c) Species diversity

d) Functional diversity

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19. During which stage of secondary succession are herbaceous plants typically dominant, paving the way for taller vegetation to follow?

a) Climax community

b) Establishment phase

c) Initial colonization

d) Pioneer stage

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20. What type of succession occurs on bare rock surfaces or areas devoid of soil and organic matter?

a) Climax Succession

b) Secondary Succession

c) Primary Succession

d) Pioneer Succession

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21. What is the primary cause of the Edge Effect on species diversity in fragmented ecosystems?

a) Soil degradation

b) Human disturbance

c) Increased competition

d) Altered microclimates

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22. In the context of species diversity, what does the term Shannon Index measure?

a) Species richness

b) Evenness of species

c) Genetic diversity

d) Ecological succession

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23. Which factor contributes to higher species diversity in tropical rainforests than temperate forests?

a) Harsher climatic conditions

b) Limited niche availability

c) Greater environmental stability

d) Lower productivity

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24. How does the R/K selection theory relate to species diversity in ecological succession?

a) It categorizes species based on their reproductive strategies

b) It explains the role of species in nutrient cycling

c) It measures species richness in climax communities

d) It describes the interaction between predator and prey during succession

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25. Which pioneer species is often associated with the early stages of primary succession in terrestrial ecosystems?

a) Ferns

b) Mosses

c) Grasses

d) Lichens

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Next: Basis of Ecosystem Classification & Biomes


  1. Odum, Eugene P. (1993) Ecology and Our Endangered Life-Support Systems, Sinauer Associates Inc., 3rd edition.
  2. Singh, R. B., and Sinha, R. K. (2017) Environmental Science: Earth as a Living Planet, Khanna Publishers, 1st edition.
  3. Sharma, P. D., and Jha, R. (2017) Environmental Biology, Rastogi Publications, 1st edition.
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