MCQ
upsc-p1-environment-ecology-ecosystem MCQ - Practice Questions with Answers
Solve 13 upsc-p1-environment-ecology-ecosystem questions for RAS/RPSC preparation.
Practice questions
Q1Consider the following statements about restoration and rehabilitation: 1. Ecological restoration seeks to recover ecosystem structure and function rather than merely create visual greenery. 2. Rehabilitation necessarily returns a degraded site fully to its former ecological state. Which of the statements given above is/are correct? Select the correct answer using the code given below.
Statement 1 is correct. Restoration aims to recover ecological structure and function; for a wetland, this includes hydrology, native species, nutrient processing and habitat value. Statement 2 is incorrect because rehabilitation may make a degraded site useful without fully returning it to its former ecological condition.
Q2Arrange the following stages of the mitigation hierarchy in the order in which they are applied to development projects: 1. Restoration 2. Avoidance 3. Offset 4. Minimisation Select the correct answer using the code given below.
Option D gives the correct sequence: avoidance first, followed by minimisation, restoration and finally offset. The hierarchy prioritises preventing harm before attempting later repair or compensation.
Q3Match List I with List II and select the correct answer using the code given below. List I (Ecosystem function) A. Food and fibre B. Flood moderation and carbon storage C. Cultural values D. Nutrient cycling List II (Service category) 1. Regulating service 2. Supporting service 3. Provisioning service 4. Cultural service
Option B is correct. Food and fibre are provisioning services; flood moderation and carbon storage are regulating services; cultural values form cultural services; and nutrient cycling is a supporting service.
Q4Match List I with List II and select the correct answer using the code given below. List I A. Pyramid of number B. Pyramid of biomass C. Pyramid of energy D. Detritus food chain List II 1. Energy flow per unit area per unit time 2. Count of organisms at each trophic level 3. Standing biomass at each trophic level 4. Begins with dead organic matter
Option B is correct. A number pyramid counts organisms, a biomass pyramid records standing biomass, and an energy pyramid records energy flow per unit area per unit time. A detritus food chain begins with dead organic matter.
Q5With reference to biogeochemical cycles, consider the following statements: 1. Carbon and nitrogen cycles have major atmospheric reservoirs and are relatively globally connected. 2. The phosphorus cycle has its major reservoir in rocks or soil and is comparatively slow. 3. The phosphorus cycle has a large atmospheric phase that rapidly reconnects distant ecosystems. Which of the statements given above are correct? Select the correct answer using the code given below.
Statements 1 and 2 are correct. Carbon and nitrogen are gaseous cycles with major atmospheric reservoirs, whereas phosphorus is mainly sedimentary, with a major rock or soil reservoir. Statement 3 is incorrect because the phosphorus cycle has no large atmospheric phase.
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6With reference to productivity and standing crop in an ecosystem, consider the following statements: 1. Gross primary productivity is the rate at which producers fix energy through photosynthesis. 2. Net primary productivity is the biomass remaining after producers expend energy in respiration and is available to herbivores. 3. Standing crop denotes the rate at which living biomass is formed over time. Which of the statements given above are correct? Select the correct answer using the code given below.
7With reference to ecological pyramids, consider the following statements: 1. A pyramid of number may be inverted in a tree ecosystem. 2. A pyramid of biomass may be inverted in an aquatic ecosystem. 3. A pyramid of energy may be inverted when producer standing biomass is low. Which of the statements given above are correct? Select the correct answer using the code given below.
8Consider the following two statements about ecological succession: Statement I: Secondary succession is generally faster than primary succession. Statement II: Secondary succession begins where soil, a seed bank or organic matter remains after disturbance. Which one of the following is correct in respect of the above statements?
9Match List I with List II: List I (Process) A. Nitrogen fixation B. Nitrification C. Denitrification D. Weathering in the phosphorus cycle List II (Result) 1. Conversion of atmospheric nitrogen into usable forms 2. Formation of nitrates 3. Return of nitrogen to the atmospheric pool 4. Release of phosphate from rocks Select the correct answer using the code given below.
10Consider the following statements about trophic energy transfer: 1. The commonly taught 10 percent law is an approximation rather than a fixed mathematical constant for every ecosystem. 2. Losses through respiration, movement, heat, undigested material and excretion help explain why long food chains are uncommon. Which of the statements given above is/are correct? Select the correct answer using the code given below.
11In hydrarch succession, arrange the following stages from earlier to later: 1. Woodland 2. Reed swamp 3. Floating plants 4. Marsh-meadow Select the correct answer using the code given below.
12Consider the following two statements about eutrophication: Statement I: Nutrient enrichment may increase algal growth while reducing dissolved oxygen and fish diversity. Statement II: A rise in biological production always indicates improved ecological health of a water body. Which one of the following is correct in respect of the above statements?
13Consider the following statements about ecosystem productivity: 1. Standing crop is the living biomass present at a particular time. 2. Net primary productivity is the producer biomass remaining after plant respiration. 3. Secondary productivity is the rate of biomass formation by consumers. Which of the statements given above are correct? Select the correct answer using the code given below.