Which of the following statements about food chains is correct?
Energy is lost as heat at each trophic level, following the second law of thermodynamics.
Ref: NCERT Class 12 Biology Chapter 12: Ecosystem Decomposition - Process and Factors
#food web
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Which of the following statements about food webs is correct?
Food webs consist of multiple interconnected food chains, showing the complex feeding relationships within an ecosystem.
Ref: NCERT Class 12 Biology Chapter 12: Ecosystem Ecosystem - Structure Components Stratification
Which of the following is a correct statement about food webs?
Food webs are formed by multiple interconnected food chains and illustrate complex feeding relationships in an ecosystem.
Ref: NCERT Class 12 Biology Chapter 12: Ecosystem Ecosystem - Structure Components Stratification
Which statement about food webs is correct?
Food webs are complex networks of interconnected food chains that show multiple feeding relationships in an ecosystem.
Ref: NCERT Class 12 Biology Chapter 12: Ecosystem Ecosystem - Structure Components Stratification
Collapse of intermediate trophic level species mainly causes:
“Drastic ecosystem changes at both higher and lower trophic levels” for collapse of intermediate trophic level species mainly causes. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Ecosystem processes are constrained by energy conservation and by the cycling of matter. Energy enters mainly through primary production, is lost as metabolic heat at every transfer, and therefore cannot be recycled in the way that carbon, nitrogen, phosphorus, or water can. The remaining alternatives—“Stability in all
Ref: Fundamentals of Ecology, Odum & Barrett, 5th Ed., Ch. 4
Biomass accumulation at lower trophic levels in top-down control is directly influenced by:
“Higher trophic level predation” for biomass accumulation at lower trophic levels in top-down control is directly influenced by. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Rates depend on temperature, moisture, substrate quality, consumer physiology, and the elemental balance between organisms and their food. These controls explain why the same process can differ among terrestrial, freshwater, and marine systems without changing its definition. The remaining alternatives—“Nutrient availabilit
Ref: Fundamentals of Ecology, Odum & Barrett, 5th Ed., Ch. 4
What is a characteristic of 'wasp-waist' ecosystems?
“Dominance at an intermediate trophic level” for what is a characteristic of 'wasp-waist' ecosystems. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Ecosystem processes are constrained by energy conservation and by the cycling of matter. Energy enters mainly through primary production, is lost as metabolic heat at every transfer, and therefore cannot be recycled in the way that carbon, nitrogen, phosphorus, or water can. The remaining alternatives—“High nutrient availability”, “Control by apex pr
Ref: Fundamentals of Ecology, Odum & Barrett, 5th Ed., Ch. 4
Which type of ecosystem control involves a trophic cascade?
“Top-down” for which type of ecosystem control involves a trophic cascade. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. The relevant inference should follow the pathway from resource supply to organismal uptake and then to ecosystem-level flux. Productivity, trophic transfer, decomposition, and nutrient regeneration are connected, but each measures a different part of that pathway. The remaining alternatives—“Bottom-up”, “Wasp-waist”, “Abiotic”—refer to different states, processes, or scales an
Ref: Fundamentals of Ecology, Odum & Barrett, 5th Ed., Ch. 4
Connectance in food web is calculated by:
Food-web connectance is the fraction of possible feeding links that are actually realized, calculated as actual links divided by potential links. If directed links among S species are allowed, potential links may be S², S(S−1), or another denominator depending on whether cannibalism and basal species are included. Because conventions differ, comparisons require the same definition and sampling effort. Connectance influences possible pathways for energy flow and indirect effects, but observed values can decline artificially as more poorly resolved species are added. Energy budgets must distingu
Ref: Fundamentals of Ecology, Odum & Barrett, 5th Ed., Ch. 3
Which is NOT correct about food web energy flow?
The keyed exception is “Herbivore efficiency higher in oceans.” In the context of which is not correct about food web energy flow, that statement differs from the governing ecological pattern and must be evaluated against the mechanism rather than accepted from wording alone. Rates depend on temperature, moisture, substrate quality, consumer physiology, and the elemental balance between organisms and their food. These controls explain why the same process can differ among terrestrial, freshwater, and marine systems without changing its definition. The remaining alternatives—“Herbivores enhance
Ref: Ecology: From Individuals to Ecosystems, Begon et al., 5th Ed., Ch. 17-19