NCERT Class 12 Environment & Ecology — Chapter 2: Ecosystem

Which process among the following is most hindered under anaerobic conditions and low temperature, leading to organic matter build-up?

Match List I with List II and select the correct answer using the code given below: List I | List II A. Phytoplankton | 1. Autotrophs (Macrophytes) B. Zooplankton | 2. Decomposers C. Fungi | 3. Autotrophs (Microscopic) D. Floating/submerged plants | 4. Consumers

Match List I with List II and select the correct answer using the code given below: List I | List II A. Fragmentation | 1. Enzymatic degradation into simpler inorganic forms B. Leaching | 2. Breakdown of detritus into smaller particles by detritivores C. Catabolism | 3. Water-soluble nutrients move down soil profile D. Humification | 4. Formation of dark, colloidal, resistant substance

How does the chemical composition of detritus affect the rate of decomposition?

Consider the following pairs: 1. Aquatic ecosystem - Grazing food chain is the major energy conduit 2. Terrestrial ecosystem - Detritus pathway dominates energy transfer 3. Omnivores - Can link grazing and detritus chains 4. Decomposers - Primary consumers of live plant tissue Which of the above are correctly matched?

Which food chain begins with dead organic matter as the energy source?

Which type of ecological pyramid is generally observed for biomass in a marine ecosystem?

Which group of organisms typically functions as primary consumers in an aquatic ecosystem?

In the context of an example freshwater pond, which component is correctly matched with its role?

In a terrestrial ecosystem, a much larger fraction of energy flows through which pathway?

In an aquatic ecosystem, which set correctly identifies the components placed primarily at the bottom sediments?

Consider the following statements regarding energy flow and food chains: 1. Energy trapped in an organism remains in the ecosystem indefinitely even after degradation. 2. Death of organisms initiates the detritus pathway. 3. The grazing food chain is connected to the detritus food chain at some levels. Which of the statements given above are correct?

Which of the following sets correctly lists the four major functional aspects displaying an ecosystem as a unit?

Which pyramid necessarily remains upright regardless of ecosystem type?

In a forest ecosystem, which component typically occupies the top vertical stratum?

Which of the following terms correctly describes the nature of energy flow in an ecosystem?

Why is the measurement of biomass in terms of dry weight preferred over fresh weight?

Consider the following pairs: 1. Forest - Terrestrial ecosystem 2. Estuary - Aquatic ecosystem 3. Aquarium - Natural ecosystem 4. Biosphere - Local ecosystem How many of the above pairs are correctly matched?

Which statement about primary and secondary productivity is correct?

Consider the following pairs: 1. Forest - Terrestrial ecosystem 2. Estuary - Aquatic ecosystem 3. Aquarium - Man-made ecosystem 4. Biosphere - Local ecosystem How many of the above pairs are correctly matched?

Which of the following correctly states the directionality of energy movement in an ecosystem?

Which component of incident solar radiation is potentially usable for photosynthesis?

Which of the following is a correct feature of humus in soils?

In a terrestrial ecosystem, which group constitutes the major producers?

Which of the following most likely slows down the rate of decomposition under a given climate?

Consider the following statements regarding decomposition: 1. Decomposition is largely an oxygen-requiring process. 2. Low temperature and anaerobiosis accelerate the decomposition process. 3. All steps of decomposition occur sequentially and never overlap. Which of the statements given above is/are correct?

In a marine ecosystem, an inverted pyramid of biomass is typically observed because:

Why is measurement of biomass in terms of dry weight considered more accurate?

Match List I with List II and select the correct answer using the code given below: List I | List II A. Producer | 1. Phytoplankton B. Primary consumer | 2. Man C. Secondary consumer | 3. Earthworm D. Detritivore | 4. Goat

Consider the following pairs regarding ecosystem dynamics: 1. Aquatic ecosystem - Grazing food chain is the major energy conduit 2. Terrestrial ecosystem - Detritus pathway dominates energy transfer 3. Omnivores - Can link grazing and detritus chains 4. Decomposers - Primary consumers of live plant tissue Which of the pairs given above are correctly matched?

In ecology, which of the following statements correctly describes the concept of a standing crop?

Which of the following correctly lists the abiotic components of a pond ecosystem?

Consider the following statements regarding ecological pyramids: 1. In most ecosystems, pyramids of number, biomass, and energy are upright. 2. A single tree ecosystem always exhibits an upright pyramid of numbers. 3. The energy content at a lower trophic level is always higher than at the succeeding higher trophic level. Which of the statements given above is/are correct?

Which of the following best illustrates a natural food web connectivity?

Which of the following correctly identifies the consumer category for molluscs in aquatic systems?

Match List I with List II and select the correct answer using the code given below: List I | List II A. Grassland | 1. Terrestrial ecosystem B. River | 2. Aquatic ecosystem (Transitional) C. Estuary | 3. Aquatic ecosystem (Lotic) D. Desert | 4. Terrestrial ecosystem (Arid)

Which process directly results in the movement of water-soluble inorganic nutrients down the soil profile, often rendering them temporarily unavailable?

Which of the following factors influence primary productivity in an area? 1. Plant species present 2. Environmental factors 3. Nutrient availability 4. Photosynthetic capacity Select the correct answer using the code given below:

With reference to the functional attributes of ecosystems, which one of the following correctly matches a process to its outcome?

In an upright pyramid of numbers for a grassland, which pattern is most consistent?

Which of the following is most appropriate as the base for constructing pyramids in most ecosystems?

Match List I with List II and select the correct answer using the code given below: List I | List II A. Gaseous cycle | 1. Reservoir in atmosphere or hydrosphere B. Sedimentary cycle | 2. Reservoir in Earth’s crust (e.g., Phosphorus) C. Carbon cycle | 3. Reservoir in atmosphere (e.g., Carbon) D. Phosphorus cycle | 4. Reservoir in Earth’s crust (General)

In ecology, mineralisation refers to which of the following transitions during the decomposition of organic matter?

Which one of the following is an example of a man-made ecosystem?

Which of the following statements are correct regarding ecosystem functions? 1. Nutrient cycling involves the one-time use of elements before they exit the ecosystem. 2. Ecosystem services include purification of air and water by forests. 3. Sedimentary nutrient cycles have the atmosphere as the main reservoir.

Which of the following statements best captures why energy cannot be recycled in ecosystems?

Consider the following: 1. Phytoplankton 2. Zooplankton 3. Higher aquatic plants Which of the above can act as producers in an aquatic ecosystem?

Which of the following correctly identifies common detritivores in many ecosystems?

Which of the following constitutes the primary autotrophic component in a pond ecosystem?

What is the term used to describe the vertical distribution of different species occupying different levels in a biotic community?

Which of the following represents an example of an anthropogenic or man-made ecosystem?

In a pond ecosystem, decomposers are most abundantly found in which of the following zones?

In an ecosystem, secondary productivity is defined as the rate of formation of new organic matter by which group?

During decomposition, what is the dark-coloured, amorphous substance formed that is highly resistant to microbial action?

Which of the following conditions is essential for the process of decomposition in soils?

Which climatic conditions are most favourable for rapid decomposition of detritus?

In an aquatic ecosystem, which food chain serves as the major conduit for energy flow?

Which term is used to describe organisms that meet their energy requirements by degrading dead organic matter?

Which of the following organisms functions as a detritivore in terrestrial ecosystems?

According to the ten % law, what fraction of energy is approximately transferred from one trophic level to the next?

Which functional group is not given a place in ecological pyramids despite its vital role in the ecosystem?

Which process results in the release of inorganic nutrients from humus?

Which step in the process of decomposition involves the physical breakdown of detritus into smaller particles?

In the context of energy flow, which pair is correctly matched?

Which of the following is NOT correctly stated regarding detritus?

Which process involves the downward movement of water-soluble inorganic nutrients into the soil horizon?

What does the term 'productivity' refer to in the context of ecosystem function?

In an ecological pyramid, what does the base level always represent?

Which one of the following correctly identifies the primary consumers in a grazing food chain?