Part 9 – Ecological Succession
Part 9 – Ecological Succession (25 MCQs)
Q1.
Ecological succession refers to:
a) Gradual replacement of one community by another
b) Sudden change in ecosystem
c) Increase in biodiversity only
d) Seasonal migration of organisms
Answer: a) Gradual replacement of one community by another
Explanation:
Succession = natural, predictable process of community development leading to climax.
Q2.
Primary succession occurs:
a) On newly exposed rock or bare land
b) On already existing soil
c) In secondary forests
d) In man-made gardens
Answer: a) On newly exposed rock or bare land
Explanation:
Primary succession starts on areas with no soil/organic matter.
Q3.
Secondary succession occurs on:
a) Bare rock
b) Newly formed sand dunes
c) Abandoned cropland
d) Lava after eruption
Answer: c) Abandoned cropland
Explanation:
Soil is already present → secondary succession is faster.
Q4.
The first organisms to colonize a bare rock are:
a) Mosses
b) Lichens
c) Grasses
d) Shrubs
Answer: b) Lichens
Explanation:
Lichens are pioneer species → secrete acids → weather rocks.
Q5.
Hydrarch succession begins in:
a) Dry soil
b) Bare rock
c) Shallow water bodies
d) Desert sand
Answer: c) Shallow water bodies
Explanation:
Hydrarch starts in aquatic habitats → proceeds toward land.
Q6.
Xerarch succession begins in:
a) Desert or dry habitat
b) Shallow lake
c) Wetland
d) River
Answer: a) Desert or dry habitat
Explanation:
Xerarch succession begins on dry substrates (rock, sand).
Q7.
During hydrarch succession, which stage appears first after phytoplankton?
a) Rooted submerged plants
b) Rooted floating plants
c) Free-floating plants
d) Trees
Answer: a) Rooted submerged plants
Explanation:
Phytoplankton → submerged plants → floating → reeds → shrubs → forest.
Q8.
In xerarch succession, lichens are followed by:
a) Shrubs
b) Mosses
c) Herbs
d) Grasses
Answer: b) Mosses
Explanation:
Sequence: Lichens → mosses → herbs → shrubs → trees.
Q9.
Which succession occurs more rapidly?
a) Primary
b) Secondary
c) Both equal
d) Neither
Answer: b) Secondary
Explanation:
Soil already present, hence faster.
Q10.
The final stable community in succession is called:
a) Seral stage
b) Pioneer community
c) Climax community
d) Transitional stage
Answer: c) Climax community
Explanation:
Stable, self-sustaining, in equilibrium with environment.
Q11.
Which is an example of secondary succession?
a) Newly formed lava
b) Abandoned agricultural field
c) Bare sand dunes
d) Retreating glacier
Answer: b) Abandoned agricultural field
Explanation:
Soil present → secondary succession.
Q12.
The intermediate communities in succession are called:
a) Climax
b) Seral communities
c) Pioneer species
d) Ecotones
Answer: b) Seral communities
Explanation:
Transitional communities between pioneer and climax.
Q13.
Succession on sand dunes is:
a) Hydrarch
b) Xerarch
c) Lithosere
d) Psammosere
Answer: d) Psammosere
Explanation:
Succession on sandy areas = psammosere.
Q14.
Succession on rocks is:
a) Hydrosere
b) Lithosere
c) Psammosere
d) Halosere
Answer: b) Lithosere
Explanation:
Lithosere = succession starting on bare rock.
Q15.
Succession in saline areas is called:
a) Psammosere
b) Lithosere
c) Halosere
d) Hydrosere
Answer: c) Halosere
Explanation:
Halo = salt → succession in saline habitats.
Q16.
Which species is a pioneer in xerarch succession?
a) Lichens
b) Mosses
c) Grasses
d) Trees
Answer: a) Lichens
Explanation:
Lichens secrete acids and initiate soil formation.
Q17.
During succession, biodiversity generally:
a) Decreases
b) Increases
c) Remains constant
d) Fluctuates randomly
Answer: b) Increases
Explanation:
Species richness increases from pioneer to climax.
Q18.
In hydrarch succession, climax community is usually:
a) Plankton
b) Grassland
c) Forest
d) Desert scrub
Answer: c) Forest
Explanation:
Aquatic habitats → terrestrial climax (forest).
Q19.
Which is NOT a characteristic of climax community?
a) Stable
b) Self-sustaining
c) Short-lived
d) In equilibrium
Answer: c) Short-lived
Explanation:
Climax communities are long-lasting and stable.
Q20.
Which is an example of pioneer species in primary succession on rocks?
a) Algae
b) Lichens
c) Grass
d) Shrubs
Answer: b) Lichens
Explanation:
First colonizers of bare rock.
Q21.
Succession on water-logged soil is called:
a) Psammosere
b) Hydrosere
c) Lithosere
d) Halosere
Answer: b) Hydrosere
Explanation:
Water → hydrosere succession.
Q22.
Which of the following is NOT a seral stage in hydrarch succession?
a) Submerged stage
b) Floating stage
c) Lichen stage
d) Reed swamp stage
Answer: c) Lichen stage
Explanation:
Lichens appear in xerarch succession, not hydrarch.
Q23.
Climax communities in dry habitats are generally:
a) Forests
b) Grasslands or deserts
c) Lakes
d) Swamps
Answer: b) Grasslands or deserts
Explanation:
Depends on water availability.
Q24.
Succession is important ecologically because:
a) It restores biodiversity
b) It stabilizes ecosystems
c) It creates soil fertility
d) All of the above
Answer: d) All of the above
Explanation:
Succession = process of ecosystem recovery and stability.
Q25.
Who proposed the concept of “climax community”?
a) Clements
b) Darwin
c) Odum
d) Lindeman
Answer: a) Clements
Explanation:
Frederic Clements → ecological succession & climax theory.