Part 6 – Pyramids of Number
Part 6 – Pyramids of Number (Upright, Inverted, Case Studies)
(25 MCQs with answers and detailed explanations, NCERT Class 12 + NEET UG level)
Q1.
An ecological pyramid represents:
a) Nutrient cycles
b) Trophic structure of ecosystem
c) Genetic diversity
d) Succession stages
Answer: b) Trophic structure of ecosystem
Explanation:
Pyramids show energy/number/biomass relationships across trophic levels.
Q2.
In most ecosystems, the pyramid of number is:
a) Upright
b) Inverted
c) Irregular
d) None
Answer: a) Upright
Explanation:
Producers > herbivores > carnivores → upright.
Q3.
Which ecosystem often shows an inverted pyramid of number?
a) Forest
b) Grassland
c) Pond
d) Desert
Answer: a) Forest
Explanation:
One big tree → many herbivores → even more parasites.
Q4.
In a grassland ecosystem, the pyramid of number is:
a) Upright
b) Inverted
c) Cylindrical
d) Irregular
Answer: a) Upright
Explanation:
Grass (many) → herbivores (less) → carnivores (few).
Q5.
In a pond ecosystem, the pyramid of number is:
a) Upright
b) Inverted
c) Irregular
d) None
Answer: a) Upright
Explanation:
Phytoplankton > zooplankton > fishes.
Q6.
Which of the following can result in a spindle-shaped pyramid of number?
a) Parasites
b) Herbivores
c) Decomposers
d) Producers
Answer: a) Parasites
Explanation:
One host can support many parasites → inverted pyramid at higher levels.
Q7.
In pyramid of number, the producer level is always:
a) At the top
b) At the base
c) At the middle
d) Absent
Answer: b) At the base
Explanation:
Pyramids always start with producers.
Q8.
Inverted pyramid of number is common in:
a) Grassland ecosystem
b) Aquatic ecosystem
c) Forest ecosystem
d) Desert ecosystem
Answer: c) Forest ecosystem
Explanation:
Few large trees → many herbivores → more parasites.
Q9.
The pyramid of number does not consider:
a) Size of organisms
b) Number of individuals
c) Trophic levels
d) Population
Answer: a) Size of organisms
Explanation:
One large tree = one producer, but biomass may be huge.
Q10.
Which of the following is a limitation of pyramid of number?
a) Ignores biomass
b) Ignores energy flow
c) May give inverted shape
d) All of the above
Answer: d) All of the above
Explanation:
Pyramid of number can be misleading compared to biomass or energy pyramids.
Q11.
An example of an inverted pyramid of number is:
a) Grassland ecosystem
b) Pond ecosystem
c) Forest with parasites
d) Desert ecosystem
Answer: c) Forest with parasites
Explanation:
One tree → many herbivores → many parasites.
Q12.
In pyramid of number, tertiary consumers are always:
a) More in number than producers
b) Fewer than producers
c) Equal to producers
d) Independent of producers
Answer: b) Fewer than producers
Explanation:
Energy decreases upwards → fewer individuals at top.
Q13.
Pyramid of number in a parasitic food chain is generally:
a) Upright
b) Inverted
c) Irregular
d) Circular
Answer: b) Inverted
Explanation:
Many parasites feed on one host → inverted.
Q14.
Which trophic level is narrowest in upright pyramid of number?
a) Producers
b) Primary consumers
c) Secondary consumers
d) Top carnivores
Answer: d) Top carnivores
Explanation:
Fewest individuals at highest level.
Q15.
Which scientist first proposed ecological pyramids?
a) Odum
b) Lindeman
c) Charles Elton
d) Tansley
Answer: c) Charles Elton
Explanation:
Elton introduced the concept of ecological pyramids (1927).
Q16.
What does a pyramid of number represent?
a) Relative biomass
b) Relative population size at each trophic level
c) Energy flow
d) Nutrient recycling
Answer: b) Relative population size at each trophic level
Explanation:
It counts number of organisms per trophic level.
Q17.
In forest ecosystems, the pyramid of number is often:
a) Upright
b) Inverted
c) Cylindrical
d) Absent
Answer: b) Inverted
Explanation:
Few trees, many herbivores, numerous parasites.
Q18.
Which pyramid can sometimes be spindle-shaped due to parasites?
a) Pyramid of number
b) Pyramid of biomass
c) Pyramid of energy
d) All pyramids
Answer: a) Pyramid of number
Explanation:
Hosts → many parasites → pyramid bulges at top.
Q19.
What is at the base of all ecological pyramids?
a) Top carnivores
b) Producers
c) Decomposers
d) Herbivores
Answer: b) Producers
Explanation:
They are the energy entry point.
Q20.
In a parasitic chain, the pyramid of number is:
a) Upright
b) Inverted
c) Cylindrical
d) Irregular
Answer: b) Inverted
Explanation:
One host supports many parasites.
Q21.
Which pyramid can misrepresent ecosystem structure due to organism size difference?
a) Pyramid of energy
b) Pyramid of biomass
c) Pyramid of number
d) All pyramids
Answer: c) Pyramid of number
Explanation:
One tree = one producer, though huge biomass.
Q22.
Why is the pyramid of number upright in grassland?
a) Many grasses support fewer herbivores and even fewer carnivores
b) Few grasses support many herbivores
c) Herbivores outnumber producers
d) Carnivores are more numerous
Answer: a) Many grasses support fewer herbivores and even fewer carnivores
Explanation:
Energy decreases as we move up trophic levels.
Q23.
Which pyramid is always upright?
a) Number
b) Biomass
c) Energy
d) All of them
Answer: c) Energy
Explanation:
Only energy pyramid is always upright.
Q24.
In pyramid of number, secondary consumers are:
a) Always more than herbivores
b) Always fewer than herbivores
c) Always equal to producers
d) Independent of herbivores
Answer: b) Always fewer than herbivores
Explanation:
Energy loss ensures fewer individuals upward.
Q25.
The pyramid of number in a forest ecosystem often looks:
a) Upright
b) Inverted
c) Irregular
d) Cylindrical
Answer: b) Inverted
Explanation:
One tree → many herbivores → even more parasites.
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