Part 1 – Ecosystem Basics: Definition, Structure, Types, Patterns
Chapter 12 – Ecosystem (NCERT Class 12, NEET UG relevant)
Subtopic Breakdown (NCERT-based, with exclusions applied)
- Ecosystem Basics – definition, structure, components, types (natural, artificial, terrestrial, aquatic).
- Components of Ecosystem – abiotic & biotic; producers, consumers, decomposers.
- Productivity in Ecosystems – GPP, NPP, secondary productivity, ecological efficiency.
- Decomposition – processes (fragmentation, leaching, catabolism, humification, mineralisation), detritus food chain.
- Energy Flow in Ecosystem – 10% law, Lindeman’s law, food chains, food webs.
- Pyramids of Number – upright, inverted, exceptions.
- Pyramids of Biomass – upright (terrestrial), inverted (aquatic).
- Pyramids of Energy – always upright, ecological significance.
- Ecological Succession
- Nutrient Cycles
Division into 8 Parts (25 MCQs each = 200 total)
- Part 1: Ecosystem – definition, types, structure, patterns
- Part 2: Ecosystem components – abiotic & biotic, trophic levels
- Part 3: Productivity – GPP, NPP, ecological efficiency
- Part 4: Decomposition – processes, detritus food chain
- Part 5: Energy flow – food chains, food webs, 10% law
- Part 6: Pyramids of Number – upright, inverted, case studies
- Part 7: Pyramids of Biomass – patterns in terrestrial & aquatic ecosystems
- Part 8: Pyramids of Energy – universal upright shape & importance
- Part 9: Ecological Succession
- Part 10: Nutrient Cycles
Part 1 – Ecosystem Basics: Definition, Structure, Types, Patterns
Q1.
The ecosystem is best defined as:
a) A group of similar organisms in an area
b) A group of populations interacting
c) Community plus its physical environment
d) A large biome
Answer: c) Community plus its physical environment
Explanation:
- (a) → Population, not ecosystem.
- (b) → Community, not ecosystem.
- (c) Correct → Ecosystem = community + abiotic factors.
- (d) → Biome is larger.
Q2.
Who coined the term “ecosystem”?
a) Ernst Haeckel
b) Eugene Odum
c) A.G. Tansley
d) Charles Elton
Answer: c) A.G. Tansley
Explanation:
- (a) → Coined “ecology.”
- (b) → Father of modern ecology.
- (c) Correct → Coined “ecosystem” (1935).
- (d) → Pioneer in animal ecology.
Q3.
Which of the following is a natural ecosystem?
a) Aquarium
b) Grassland
c) Botanical garden
d) Crop field
Answer: b) Grassland
Explanation:
- (a) Aquarium → Artificial.
- (b) Correct → Natural terrestrial ecosystem.
- (c) Artificial.
- (d) Agroecosystem = man-made.
Q4.
Which is an artificial ecosystem?
a) Forest
b) Grassland
c) Pond
d) Aquarium
Answer: d) Aquarium
Explanation:
- Forest, grassland, pond = natural.
- Aquarium is artificial and man-maintained.
Q5.
Which ecosystem is most stable?
a) Forest
b) Desert
c) Grassland
d) Lake
Answer: a) Forest
Explanation:
Forests are self-regulated, complex, highly stable.
Q6.
Which is NOT a component of ecosystem structure?
a) Producers
b) Consumers
c) Nutrient cycles
d) Abiotic environment
Answer: c) Nutrient cycles
Explanation:
Nutrient cycles = processes, not structural component.
Q7.
Which forms the functional unit of nature?
a) Community
b) Ecosystem
c) Biome
d) Biosphere
Answer: b) Ecosystem
Explanation:
Ecosystem = basic functional ecological unit.
Q8.
Which of the following is NOT a man-made ecosystem?
a) Crop field
b) Garden
c) Lake
d) Aquarium
Answer: c) Lake
Explanation:
Lake is natural, others are artificial.
Q9.
The largest ecosystem of the world is:
a) Forest
b) Grassland
c) Ocean
d) Desert
Answer: c) Ocean
Explanation:
Covers ~70% Earth surface → largest ecosystem.
Q10.
Which ecosystem is considered the most productive?
a) Ocean
b) Desert
c) Tropical rainforest
d) Tundra
Answer: c) Tropical rainforest
Explanation:
Highest productivity due to warm, moist, year-round growth.
Q11.
Which ecosystem has the least productivity?
a) Desert
b) Ocean
c) Tundra
d) Grassland
Answer: a) Desert
Explanation:
Harsh abiotic factors, water scarcity → lowest productivity.
Q12.
What is the main function of producers in an ecosystem?
a) Decompose matter
b) Fix energy into organic matter
c) Consume other organisms
d) None
Answer: b) Fix energy into organic matter
Explanation:
Producers capture solar energy and synthesize food.
Q13.
Which of the following is a pioneer ecosystem ecologist, called “Father of Ecology”?
a) Eugene Odum
b) Charles Darwin
c) Ernst Haeckel
d) A.G. Tansley
Answer: a) Eugene Odum
Explanation:
He integrated ecosystem studies → called Father of Ecology.
Q14.
Which of the following is an example of terrestrial ecosystem?
a) Grassland
b) Pond
c) Lake
d) Wetland
Answer: a) Grassland
Explanation:
Grassland = land-based ecosystem.
Q15.
Which of the following is an aquatic ecosystem?
a) Desert
b) Tundra
c) River
d) Forest
Answer: c) River
Explanation:
River is aquatic → freshwater ecosystem.
Q16.
An ecosystem with high resilience:
a) Recovers slowly after disturbance
b) Recovers quickly after disturbance
c) Cannot recover
d) Becomes extinct
Answer: b) Recovers quickly after disturbance
Explanation:
Resilience = speed of recovery.
Q17.
Which of the following ecosystems is maintained entirely by man?
a) Crop field
b) Forest
c) Pond
d) Ocean
Answer: a) Crop field
Explanation:
Agroecosystem depends on human input.
Q18.
Which of the following is NOT a natural aquatic ecosystem?
a) Lake
b) River
c) Ocean
d) Aquarium
Answer: d) Aquarium
Explanation:
Aquarium is artificial.
Q19.
The ecosystem where energy input is highest is:
a) Desert
b) Tropical rainforest
c) Grassland
d) Tundra
Answer: b) Tropical rainforest
Explanation:
High solar energy input + high productivity.
Q20.
Which of the following is a lentic ecosystem?
a) Pond
b) River
c) Stream
d) Spring
Answer: a) Pond
Explanation:
Lentic = still water; lotic = flowing water.
Q21.
Which of the following is a lotic ecosystem?
a) Pond
b) Lake
c) River
d) Reservoir
Answer: c) River
Explanation:
Rivers and streams → flowing water systems.
Q22.
The basic structural and functional unit of biosphere is:
a) Population
b) Community
c) Ecosystem
d) Organism
Answer: c) Ecosystem
Explanation:
Ecosystem = structure + function together.
Q23.
Which ecosystem occupies the largest area of Earth?
a) Forests
b) Oceans
c) Grasslands
d) Wetlands
Answer: b) Oceans
Explanation:
Oceans cover ~70% of Earth.
Q24.
Which type of ecosystem is estuary?
a) Freshwater
b) Marine
c) Brackish water
d) Artificial
Answer: c) Brackish water
Explanation:
Estuaries = mix of freshwater + marine water.
Q25.
Which of the following is the most complex ecosystem?
a) Grassland
b) Pond
c) Tropical rainforest
d) Desert
Answer: c) Tropical rainforest
Explanation:
Highest biodiversity + productivity → rainforest most complex.
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