Class 12 · Biology · CBSE Board · 2016–2025

Ecosystem — Class 12 Biology PYQs

54 questions from this chapter, asked in 8 Class 12 exams between 2016–2025 — every question paper set included, duplicates removed.

54questions

8Class 12 exams

2016–2025years covered

1 / 2 / 3 / 5mark values asked

Questions asked per year

202518 Qs 20247 Qs 20234 Qs 20209 Qs 20198 Qs 20186 Qs 20176 Qs 20162 Qs

Practice questions first 10 of 54 — free

Q1MCQ20251 mark

Answer Logic

Pioneers of secondary succession on abandoned farm lands are :
[Max Marks: 1 | Set: 57/2/3]

(A)Lichens

(B)Mosses

(C)Herbaceous plants

(D)Trees

Q2MCQ20251 mark

Answer Logic

Which one of the following ecosystems has the highest gross primary productivity ?
[Max Marks: 1 | Sets: 57/1/1]

(A)Grasslands

(B)Coral reefs

(C)Mangroves

(D)Tropical rainforest

Q3MCQ20251 mark

Answer Logic

Which one of the following ecosystems has the lowest productivity ?
[Max Marks: 1 | Sets: 57/1/2]

(A)Oceans

(B)Tropical rainforest

(C)Grasslands

(D)Deserts

Q4MCQ20253 marks

Answer Logic

(A)Explain the concept of ecological pyramids. Name the three types of pyramids.

(B)How does the amount of energy change at successive trophic levels in an ecosystem ?

(C)Name the process by which phosphorus is returned to the soil. [Max Marks: 3 | Sets: 57/2/3]

Q5MCQ20251 mark

Answer Logic

What is the unit for measuring the productivity of an ecosystem ?
[Max Marks: 1 | Sets: 57/2/2]

(A)and

(C)Both

(D)kg/m²/year

Q6MCQ20251 mark

Answer Logic

Which one of the following represents the correct sequence of organisms in a grazing food chain ?
[Max Marks: 1 | Sets: 57/2/1]

(A)Grass → Insect → Frog → Snake → Hawk

(B)Grass → Grasshopper → Frog → Snake → Hawk

(C)Phytoplankton → Zooplankton → Small fish → Large fish

(D)Dead organic matter → Bacteria → Insects → Birds

Q7MCQ20251 mark

Answer Logic

The pyramid of biomass is always upright in :
[Max Marks: 1 | Sets: 57/2/3]

(A)and

(B)Aquatic ecosystem

(C)Grassland ecosystem

(D)Both

Q8MCQ20251 mark

Answer Logic

The pyramid of energy in a terrestrial ecosystem is :
[Max Marks: 1 | Sets: 57/1/3]

(A)Always upright

(B)Always inverted

(C)Upright or inverted depending upon the ecosystem

(D)Spindle shaped

Q9MCQ20251 mark

Answer Logic

Name the group of organisms which play a major role in nutrient cycling by the breakdown of dead organic matter :
[Max Marks: 1 | Sets: 57/1/3]

(A)Producers

(B)Consumers

(C)Decomposers

(D)Herbivores

Q10MCQ20251 mark

Answer Logic

According to Lindeman, the percentage of energy transferred from one trophic level to the next is approximately :
[Max Marks: 1 | Sets: 57/1/2]

(A)1%

(B)10%

(C)50%

(D)90%

Why practise Ecosystem PYQs?

Ecosystem has appeared in 8 Class 12 Biology exams we track between 2016–2025, with questions worth 1, 2, 3, 5 marks. CBSE Board examiners consistently reuse concepts and question patterns from this topic — practising its previous year questions is the most reliable way to know exactly what to expect in your exam.

Ecosystem — Class 12 Biology PYQs

Questions asked per year

Practice questions first 10 of 54 — free

Why practise Ecosystem PYQs?

Other Biology chapters

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Microbes in Human Welfare

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Biotechnology and its Applications

Organisms and Populations

Biodiversity and its Conservation