Environment, Ecology, and Biodiversity form a high-weightage, multidisciplinary component of the UPSC Civil Services Examination syllabus, intersecting with geography, biology, governance, and international relations. This domain evaluates a candidate’s understanding of ecosystem structures, biogeochemical cycles, ecological succession, wildlife conservation frameworks, pollution control acts, and global climate conventions. Practicing structured multiple-choice questions helps aspirants master ecological terminology, conservation status classifications, and statutory environmental provisions required for preliminary screening success.
1. Which of the following international agreements aims to phase out Ozone Depleting Substances (ODS) globally?
Correct Answer: b) Montreal Protocol
Explanation:
The Montreal Protocol on Substances that Deplete the Ozone Layer is a landmark international treaty designed to protect the ozone layer by phasing out the production and consumption of numerous substances responsible for ozone depletion.
2. What is the primary objective of the 'Paris Agreement' under the United Nations Framework Convention on Climate Change (UNFCCC)?
Correct Answer: b) To hold global average temperature increase to well below 2 degrees Celsius above pre-industrial levels
Explanation:
The Paris Agreement is a legally binding international treaty on climate change aiming to limit global warming to well below 2 degrees Celsius, preferably pursuing efforts to limit it to 1.5 degrees Celsius.
3. What is a 'Biodiversity Hotspot'?
Correct Answer: b) A biogeographic region with significant levels of biodiversity that is threatened by severe habitat loss
Explanation:
To qualify as a biodiversity hotspot, a region must contain at least 1,500 species of vascular plants as endemics and have lost at least 70% of its original natural habitat.
4. Which Indian state has the maximum geographic area under mangrove cover?
Correct Answer: c) West Bengal
Explanation:
West Bengal has the highest mangrove cover in India, primarily attributed to the vast Sunderbans delta, followed by Gujarat and the Andaman and Nicobar Islands.
5. The Wildlife (Protection) Act in India was enacted in which year?
Correct Answer: b) 1972
Explanation:
The Wildlife (Protection) Act was enacted in 1972 to provide comprehensive protection to wild animals, birds, and plants, and matters connected therewith across India.
6. What was the primary objective of launching 'Project Tiger' in India in 1973?
Correct Answer: b) To ensure a viable population of tigers in their natural habitats and protect them from extinction
Explanation:
Project Tiger was launched in 1973 as a centrally sponsored conservation program aimed at maintaining a sustainable population of tigers in designated tiger reserves.
7. What is 'Biological Oxygen Demand (BOD)' used as a standard indicator for?
Correct Answer: b) Measuring the amount of dissolved oxygen needed by aerobic biological organisms to break down organic material present in water
Explanation:
BOD is a vital metric for water quality assessment; higher BOD levels indicate greater organic pollution and lower available dissolved oxygen for aquatic life.
8. The term 'Eutrophication' is best described as:
Correct Answer: b) The enrichment of water bodies with plant nutrients, leading to excessive algal growth and subsequent oxygen depletion
Explanation:
Eutrophication occurs when excess nutrients, such as nitrates and phosphates from agricultural runoffs, enter water bodies, causing algal blooms that suffocate aquatic ecosystems.
9. Which organization compiles the 'Red Data Book' containing conservation status lists of threatened species?
Correct Answer: b) International Union for Conservation of Nature (IUCN)
Explanation:
The IUCN Red List of Threatened Species, established in 1964, is the world's most comprehensive information source on the global extinction risk status of animal, fungus, and plant species.
10. Which of the following is a greenhouse gas that occurs naturally and is also emitted through agricultural practices such as flooded paddy cultivation?
Correct Answer: b) Methane
Explanation:
Methane (CH4) is a potent greenhouse gas released during anaerobic decomposition in wetlands, livestock digestion, and water-logged paddy fields.
11. What is the primary significance of the 'Ramsar Convention'?
Correct Answer: a) Conservation and wise use of wetlands and their resources
Explanation:
The Ramsar Convention is an intergovernmental treaty signed in Ramsar, Iran, in 1971 for the conservation and sustainable utilization of wetlands.
12. Which organization publishes the 'Global Gender Gap Report'?
Correct Answer: b) World Economic Forum (WEF)
Explanation:
The Global Gender Gap Report is published annually by the World Economic Forum, benchmarking countries on gender-based disparities across economic, educational, health, and political indicators.
13. What is the primary goal of the 'Mission LiFE' (Lifestyle for Environment) initiative?
Correct Answer: b) Nurturing an international lifestyle that focuses on mindful and deliberate utilization rather than mindless consumption
Explanation:
Mission LiFE aims to mobilize individuals into pro-planet people who practice simple, eco-friendly daily habits to combat climate change.
14. Which animal serves as the iconic mascot and symbol of the World Wide Fund for Nature (WWF)?
Correct Answer: b) Giant Panda
Explanation:
The Giant Panda has been the iconic logo and symbol of the World Wide Fund for Nature (WWF) since its founding in 1961.
15. What is the term for species that have a disproportionately large effect on their natural environment relative to their population abundance?
Correct Answer: b) Keystone species
Explanation:
A keystone species plays a critical and unique role in maintaining the structure of an ecological community; its removal causes drastic ecosystem changes.
16. What is 'Greenwashing'?
Correct Answer: b) Disinformation disseminated by an organization to present an environmentally responsible public image
Explanation:
Greenwashing refers to the practice of making misleading or false claims about the environmental benefits of a product, service, or company practice.
17. What is the main function of the 'National Green Tribunal (NGT)' in India?
Correct Answer: b) Effective and expeditious disposal of cases relating to environmental protection and conservation of forests and natural resources
Explanation:
The NGT is a specialized statutory body established in 2010 under the National Green Tribunal Act for handling cases and speedy disposal pertaining to environmental issues.
18. Which of the following is considered a 'Keystone species' in marine coral reef ecosystems?
Correct Answer: a) Parrotfish
Explanation:
Parrotfish play a vital keystone role in coral reefs by grazing on algae that would otherwise outcompete and smother slow-growing corals.
19. What is the main objective of the 'Nagoya Protocol'?
Correct Answer: b) Fair and equitable sharing of benefits arising from the utilization of genetic resources
Explanation:
The Nagoya Protocol on Access to Genetic Resources and the Fair and Equitable Sharing of Benefits Arising from their Utilization is a supplementary agreement to the CBD.
20. The 'Cartagena Protocol on Biosafety' is primarily concerned with:
Correct Answer: a) The safe transfer, handling, and use of Living Modified Organisms (LMOs) resulting from modern biotechnology
Explanation:
The Cartagena Protocol is an international treaty governing the movements of living modified organisms resulting from modern biotechnology from one country to another.
21. Which of the following conventions addresses the control of transboundary movements of hazardous wastes and their disposal?
Correct Answer: a) Basel Convention
Explanation:
The Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their Disposal was designed to reduce the movements of hazardous waste between nations.
22. What is the primary focus of the 'Stockholm Convention'?
Correct Answer: b) Elimination or restriction of production and use of Persistent Organic Pollutants (POPs)
Explanation:
The Stockholm Convention is a global treaty to protect human health and the environment from persistent organic pollutants that accumulate in living tissue.
23. What is the 'Rotterdam Convention' about?
Correct Answer: a) Prior informed consent procedure for certain hazardous chemicals and pesticides in international trade
Explanation:
The Rotterdam Convention promotes shared responsibilities in relation to importation of hazardous chemicals through a prior informed consent procedure.
24. Which of the following terms describes the complete disappearance of a species from a specific local area or region, while it still exists elsewhere?
Correct Answer: b) Extirpation (Local extinction)
Explanation:
Extirpation refers to local extinction, where a species ceases to exist in a chosen geographic area of study, though it may continue to survive elsewhere in the world.
25. What is 'Biological Invasions' or invasive alien species primarily known to cause in native ecosystems?
Correct Answer: b) Displacement of native species, habitat alteration, and loss of biodiversity
Explanation:
Invasive alien species can outcompete native species for resources, introduce diseases, and drastically disrupt ecological balances.
26. What is the primary role of 'Lichens' in an ecological succession process?
Correct Answer: b) Pioneer species on bare rock surfaces that help in weathering and soil formation
Explanation:
Lichens act as pioneer species in primary succession on bare rocks, secreting acids that break down rock into soil particles.
27. What does 'Ecological Footprint' measure?
Correct Answer: b) The demand placed by human activities on Earth's natural regenerative ecosystems
Explanation:
An ecological footprint calculates the amount of biologically productive land and sea area needed to regenerate resources consumed and absorb wastes produced by humans.
28. Which of the following is a primary greenhouse gas with the highest atmospheric concentration among anthropogenic gases?
Correct Answer: a) Carbon dioxide (CO2)
Explanation:
Carbon dioxide is the primary anthropogenic greenhouse gas driving global climate change due to fossil fuel combustion and deforestation.
29. What is 'Biomagnification'?
Correct Answer: b) The progressive accumulation of toxic substances in organisms at higher trophic levels of a food chain
Explanation:
Biomagnification refers to the concentration of toxins (such as heavy metals or persistent pesticides) multiplying as they move up successive trophic levels in a food web.
30. What is 'Bioaccumulation'?
Correct Answer: a) The accumulation of substances, such as pesticides or heavy metals, in an organism over the course of its lifetime from its surrounding environment
Explanation:
Bioaccumulation refers to the buildup of chemicals within a single organism over time, whereas biomagnification refers to the increase across trophic levels.
31. Which of the following is a non-point source of water pollution?
Correct Answer: b) Agricultural runoff from extensive crop fields
Explanation:
Non-point source pollution comes from diffuse sources distributed over a large area, such as fertilizer and pesticide runoff from agricultural lands, making it harder to track than point sources.
32. What is the primary objective of India's 'National Action Plan on Climate Change (NAPCC)'?
Correct Answer: b) Outlining national strategies that combine climate change adaptation and mitigation through multiple core missions
Explanation:
The NAPCC comprises several national missions (Solar, Enhanced Energy Efficiency, Sustainable Habitat, Water, etc.) addressing India's climate vulnerabilities.
33. What is 'REDD+' mechanism designed to achieve?
Correct Answer: a) Reduction of emissions from deforestation and forest degradation, and conservation of forest carbon stocks in developing countries
Explanation:
REDD+ is a framework created by the UNFCCC to incentivize developing countries to reduce emissions from deforestation and forest degradation, and foster sustainable forest management.
34. Which of the following is an example of an 'Ex-situ' method of biodiversity conservation?
Correct Answer: c) Botanical Garden / Seed Bank
Explanation:
Ex-situ conservation involves the maintenance and breeding of endangered species outside their natural habitats in facilities such as zoos, botanical gardens, and seed banks.
35. Which of the following is an example of 'In-situ' biodiversity conservation?
Correct Answer: c) National Park
Explanation:
In-situ conservation involves protecting species within their natural habitats, such as national parks, wildlife sanctuaries, and biosphere reserves.
36. What is a 'Biosphere Reserve' characterized by?
Correct Answer: b) Zoned areas consisting of a core zone, buffer zone, and transition area promoting sustainable development
Explanation:
Biosphere reserves are designated under UNESCO's Man and the Biosphere (MAB) program, structured into core, buffer, and transition zones to balance conservation and human use.
37. What is 'Coral Bleaching' caused by?
Correct Answer: a) Increase in ocean water temperatures and solar irradiance causing corals to expel symbiotic algae
Explanation:
Coral bleaching occurs when environmental stressors like elevated sea temperatures cause corals to expel the zooxanthellae living in their tissues, turning them completely white.
38. What are 'CFCs' (Chlorofluorocarbons) primarily known to damage?
Correct Answer: b) Stratospheric ozone layer
Explanation:
CFCs release chlorine atoms when exposed to ultraviolet radiation in the stratosphere, which catalytically break down and destroy ozone molecules.
39. Which of the following is India's first national park, established in 1936?
Correct Answer: b) Jim Corbett National Park (formerly Hailey National Park)
Explanation:
Jim Corbett National Park in Uttarakhand was established in 1936 as Hailey National Park, making it India's oldest national park.
40. What is the primary objective of the 'CAMPA' (Compensatory Afforestation Fund Management and Planning Authority) in India?
Correct Answer: b) Ensuring compensatory afforestation and net present value payments when forest land is diverted for non-forest use
Explanation:
CAMPA funds are utilized to undertake compensatory afforestation and watershed protection measures when forest land is diverted for developmental projects.
41. What is 'Acid Rain' primarily caused by the atmospheric emission of?
Correct Answer: b) Sulfur dioxide (SO2) and Nitrogen oxides (NOx)
Explanation:
Acid rain results when sulfur dioxide and nitrogen oxides are emitted into the atmosphere, react with water, oxygen, and other chemicals to form sulfuric and nitric acids.
42. Which of the following organisms acts as a prominent biological indicator of sulfur dioxide air pollution?
Correct Answer: b) Lichens
Explanation:
Lichens are extremely sensitive to sulfur dioxide pollution and fail to grow in polluted urban or industrial environments, serving as reliable bioindicators.
43. What is 'Biological Diversity Act' of India enacted in?
Correct Answer: c) 2002
Explanation:
The Biological Diversity Act was enacted by the Parliament of India in 2002 to give effect to the provisions of the United Nations Convention on Biological Diversity (CBD).
44. What is the primary mandate of the 'National Biodiversity Authority (NBA)' established under the Biodiversity Act 2002?
Correct Answer: b) Performing facilitative, regulatory, and advisory functions for the government on conservation and sustainable use of biological resources
Explanation:
The NBA is a statutory body headquartered in Chennai that implements India's Biological Diversity Act, regulating access to biological resources and traditional knowledge.
45. What is 'Smog' a combination of?
Correct Answer: a) Smoke and fog
Explanation:
Smog is a type of air pollution originally coined from the terms smoke and fog, now commonly denoting photochemical smog produced by vehicular and industrial emissions.
46. Which of the following pollutants is a key precursor to photochemical smog formation in urban atmospheres?
Correct Answer: a) Nitrogen oxides and volatile organic compounds (VOCs)
Explanation:
Photochemical smog forms when sunlight acts on nitrogen oxides and volatile organic compounds in the atmosphere, creating ground-level ozone and other oxidants.
47. What is 'Ground-level Ozone' considered in terms of atmospheric pollution?
Correct Answer: b) A harmful secondary air pollutant and potent greenhouse gas
Explanation:
While stratospheric ozone is beneficial, ground-level (tropospheric) ozone is a harmful pollutant that damages human respiratory systems and vegetation.
48. What is the primary objective of the 'Global Environment Facility (GEF)'?
Correct Answer: b) Providing grants and concessional funding to assist in the protection of the global environment and fund green projects
Explanation:
The GEF unites international countries to fund projects related to biodiversity, climate change, international waters, land degradation, and ozone depletion.
49. What is 'CITES' (Convention on International Trade in Endangered Species of Wild Fauna and Flora) aimed at regulating?
Correct Answer: b) International trade in specimens of wild animals and plants to ensure their survival is not threatened
Explanation:
CITES is an international agreement between governments ensuring that international trade in wild animals and plants does not threaten their survival.
50. What is the 'Bonn Convention' (Convention on the Conservation of Migratory Species of Wild Animals) designed to protect?
Correct Answer: b) Migratory species of wild animals across their ranges throughout international boundaries
Explanation:
The Bonn Convention aims to conserve terrestrial, aquatic, and avian migratory species throughout their range.
51. What is 'IPBES' (Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services) often described as?
Correct Answer: a) The biodiversity equivalent of the Intergovernmental Panel on Climate Change (IPCC)
Explanation:
IPBES is an independent intergovernmental body assessing the state of biodiversity and ecosystem services to inform policy decisions.
52. What is the primary goal of the 'LEDS' (Low Emission Development Strategies) global partnership?
Correct Answer: a) Enhancing economic growth while cutting greenhouse gas emissions
Explanation:
LEDS helps countries pursue sustainable, climate-resilient economic growth with lower greenhouse gas emissions.
53. Which of the following is a key feature of 'Organic Farming'?
Correct Answer: b) Exclusion of synthetic inputs, using organic manures, crop rotation, and biological pest control
Explanation:
Organic farming relies on ecological processes, biodiversity, and natural cycles rather than synthetic fertilizers and chemical pesticides to maintain soil fertility.
54. What is 'Permaculture'?
Correct Answer: a) An approach to land management and settlement design that adopts natural ecosystems' arrangements
Explanation:
Permaculture is a system of agricultural and social design principles centered around simulating or directly utilizing the patterns and features observed in natural ecosystems.
55. What does 'Ecotourism' promote?
Correct Answer: b) Responsible travel to natural areas that conserves the environment, sustains the well-being of the local people, and involves interpretation and education
Explanation:
Ecotourism focuses on uniting conservation, communities, and sustainable travel, ensuring that tourism benefits local biodiversity and indigenous populations.
56. What is 'Agroforestry'?
Correct Answer: b) An land use management system in which trees or shrubs are grown around or among crops or pastureland
Explanation:
Agroforestry integrates trees and shrubs into agricultural and livestock systems to create environmental, economic, and social benefits.
57. What is 'Social Forestry' intended to achieve?
Correct Answer: b) Management and protection of forests and afforestation of barren lands with local community involvement to help environmental, rural, and social development
Explanation:
Social forestry aims at tree planting and management on community lands and was popularized to reduce pressure on traditional forest reserves.
58. What is 'Jhum Cultivation' (shifting agriculture) commonly associated with?
Correct Answer: b) Slash-and-burn agriculture practiced in northeastern hill regions of India
Explanation:
Jhum is a traditional shifting cultivation method where forest plots are cleared, burned for nutrients, farmed for a few years, and then left fallow to regenerate.
59. Which of the following is a major environmental concern associated with large hydroelectric dams?
Correct Answer: b) Submergence of vast forest and agricultural lands, displacement of communities, and disruption of aquatic migration
Explanation:
Large dams fragment river ecosystems, trap sediments, submerge terrestrial habitats, displace indigenous populations, and emit methane from rotting submerged biomass.
60. What is 'Fly Ash'?
Correct Answer: b) A fine powdery byproduct composed of silica and alumina produced from coal combustion in thermal power plants
Explanation:
Fly ash is generated by coal-fired power plants and poses environmental disposal challenges, though it is increasingly utilized in cement and brick manufacturing.
61. What are 'PM2.5' particles in air quality monitoring?
Correct Answer: a) Fine particulate matter with a diameter of 2.5 micrometers or less
Explanation:
PM2.5 refers to microscopic airborne particles that can penetrate deep into human lungs and enter the bloodstream, posing severe health risks.
62. What is the primary objective of the 'National Clean Air Programme (NCAP)' in India?
Correct Answer: b> Comprehensive management plan to prevent, control, and reduce air pollution in targeted Indian cities
Explanation:
NCAP is a national strategy aiming to reduce particulate matter pollution levels in designated non-attainment cities across India.
63. What is 'Bioremediation'?
Correct Answer: b) The use of microorganisms or plants to detoxify or remove pollutants from contaminated environments
Explanation:
Bioremediation harnesses biological agents like bacteria, fungi, or plants to break down hazardous environmental contaminants into harmless byproducts.
64. What is 'Phytoremediation'?
Correct Answer: a) Using specially engineered plants to absorb, accumulate, or detoxify contaminants from soil and water
Explanation:
Phytoremediation is a subcategory of bioremediation utilizing green plants to clean up polluted soils, sludges, sediments, and groundwater.
65. What is 'Ocean Acidification' driven by?
Correct Answer: b) Absorption of excess anthropogenic carbon dioxide from the atmosphere by ocean waters, lowering pH
Explanation:
When oceans absorb atmospheric CO2, chemical reactions occur that reduce seawater pH and carbonate ion concentrations, harming shell-building marine organisms.
66. Which of the following is a key impact of Ocean Acidification on marine life?
Correct Answer: b) Dissolution and weakening of calcium carbonate structures in corals, mollusks, and plankton
Explanation:
Lower carbonate ion saturation resulting from ocean acidification makes it difficult for marine organisms like corals and shellfish to build and maintain shells.
67. What is 'Blue Carbon'?
Correct Answer: b) Carbon captured and stored by coastal and marine ecosystems such as mangroves, salt marshes, and seagrasses
Explanation:
Blue carbon refers to coastal, marine, and tidal carbon sequestration capacity, which captures carbon at rates significantly higher than terrestrial forests.
68. What is 'Green Carbon'?
Correct Answer: a) Carbon stored in terrestrial forests, vegetation, and soils
Explanation:
Green carbon is the carbon sequestered by terrestrial ecosystems, notably forests and grasslands.
69. What is 'Black Carbon'?
Correct Answer: b) A component of fine particulate matter formed through incomplete combustion of fossil fuels and biomass, absorbing solar radiation
Explanation:
Black carbon (soot) is a potent short-lived climate pollutant that warms the atmosphere by absorbing sunlight and darkens snowpacks, accelerating melting.
70. What is 'Net Zero Emissions' target?
Correct Answer: b) Achieving an overall balance between greenhouse gas emissions produced and greenhouse gas emissions removed from the atmosphere
Explanation:
Net zero means any greenhouse gases released into the atmosphere are counterbalanced by an equivalent amount removed through natural sinks or carbon capture technologies.
71. Which of the following international organizations launched the 'International Solar Alliance (ISA)' jointly with India?
Correct Answer: b) Government of France
Explanation:
The International Solar Alliance was jointly launched by India and France at the COP21 UN Climate Change Conference in Paris in 2015 to promote solar energy deployment.
72. What is the primary objective of the 'LEDS' or 'National Solar Mission' in India?
Correct Answer: a) Promoting grid-connected and off-grid solar power generation to establish India as a global solar leader
Explanation:
The National Solar Mission is a major initiative of the Indian government to promote solar energy and advance sustainable energy security.
73. What is 'Biocapacity'?
Correct Answer: b) The capacity of ecosystems to produce useful biological materials and absorb waste materials generated by humans
Explanation:
Biocapacity measures the amount of biologically productive land and sea available to provide resources and absorb waste, compared against humanity's ecological footprint.
74. What is 'Ecological Succession'?
Correct Answer: b) The process by which the structure of a biological community evolves and changes over time following disturbances or on bare substrates
Explanation:
Ecological succession is the steady and gradual change in a species composition of an ecosystem over time, progressing from pioneer species to a stable climax community.
75. What is a 'Climax Community' in ecological succession?
Correct Answer: b) The final, stable, and self-sustaining community of plants and animals that represents the end stage of succession
Explanation:
A climax community is the mature, balanced terminal stage of biotic succession that remains relatively unchanged until disturbed by major natural or anthropogenic events.
76. What is 'Primary Succession'?
Correct Answer: b) Ecological succession beginning in lifeless areas where soil has not yet formed, such as newly formed volcanic islands or bare rock
Explanation:
Primary succession occurs in essentially lifeless substrates—regions where the soil is incapable of sustaining life due to factors such as lava flows or newly exposed rock.
77. What is 'Secondary Succession'?
Correct Answer: b) Succession that occurs in an area where an existing community has been partially or completely removed by a disturbance, but soil remains intact
Explanation:
Secondary succession happens faster than primary succession because pre-existing soil and some organic seed banks remain intact following events like wildfires, floods, or farming abandonment.
78. What is an 'Ecotone'?
Correct Answer: b) A transition area between two different biomes or ecosystems, often exhibiting high biodiversity
Explanation:
An ecotone is a junction zone between two adjacent ecological communities (such as where a forest meets a grassland), frequently displaying the 'edge effect' with diverse species.
79. What is the 'Edge Effect' in ecology?
Correct Answer: b) The tendency for a transition zone (ecotone) between two ecosystems to have greater species diversity and higher population density than the adjoining communities
Explanation:
The edge effect refers to changes in population or community structures that occur at the boundary of two habitats, often resulting in rich biodiversity.
80. What is a 'Niche' in ecological terms?
Correct Answer: b) The functional role, position, and interactions of a species within its ecosystem, including resource use and environmental tolerances
Explanation:
While habitat is an organism's physical address, its niche is its ecological profession—how it fits into and interacts with its ecosystem regarding food, predators, and habitat.
81. What does 'Competitive Exclusion Principle' (Gause's Law) state?
Correct Answer: a) Two species competing for the exact same limiting resources cannot coexist indefinitely if other ecological factors remain constant
Explanation:
Gause's law dictates that if two species have overlapping niches and compete for identical resources, one will outcompete the other, leading to local extinction or niche differentiation.
82. What is 'Symbiosis'?
Correct Answer: b) Any close and long-term biological interaction between two different biological organisms
Explanation:
Symbiosis encompasses various long-term interactions between distinct species, including mutualism, commensalism, and parasitism.
83. What is 'Mutualism' in ecological interactions?
Correct Answer: b) An interaction where both interacting species derive mutually beneficial fitness outcomes
Explanation:
Mutualism is a symbiotic association where both organisms benefit, such as bees pollinating flowering plants or mycorrhizal fungi associating with tree roots.
84. What is 'Commensalism'?
Correct Answer: b) An ecological interaction where one organism benefits while the other is neither helped nor harmed
Explanation:
Commensalism is a relationship where one species derives benefit while the other is unaffected, such as barnacles attaching to whales.
85. What is 'Parasitism'?
Correct Answer: a) A relationship where one organism benefits at the expense of another host organism, usually without immediately killing it
Explanation:
Parasitism is a non-mutual symbiotic relationship where the parasite benefits at the host's physiological expense.
86. What is 'Amensalism'?
Correct Answer: a) An interaction where one species is inhibited or destroyed while the other species remains unaffected
Explanation:
Amensalism is an ecological interaction where an organism inflicts damage to another organism without any intentional cost or benefit to itself (e.g., taller trees shading out smaller understory plants).
87. What is 'Biogeochemical Cycle'?
Correct Answer: b) The pathway by which chemical substances move through biotic (biosphere) and abiotic (lithosphere, atmosphere, and hydrosphere) compartments of Earth
Explanation:
Biogeochemical cycles, such as the carbon, nitrogen, and water cycles, describe how essential chemical elements circulate through living and non-living components of the planet.
88. Which of the following is a sedimentary biogeochemical cycle that lacks a significant gaseous phase in the atmosphere?
Correct Answer: c) Phosphorus cycle
Explanation:
Unlike carbon and nitrogen which have prominent gaseous atmospheric reservoirs, phosphorus has a sedimentary cycle, circulating primarily through rocks, soil, water, and living organisms.
89. What is the primary reservoir of nitrogen gas on Earth?
Correct Answer: b) The atmosphere (comprising roughly 78% nitrogen)
Explanation:
The Earth's atmosphere is the largest reservoir of nitrogen, though atmospheric N2 must be fixed by specialized bacteria or lightning before plants can utilize it.
90. What is the role of 'Nitrogen-fixing bacteria' such as Rhizobium in the nitrogen cycle?
Correct Answer: a) Converting atmospheric nitrogen gas into ammonia or nitrates usable by plants
Explanation:
Nitrogen-fixing bacteria convert inert atmospheric nitrogen into biologically available nitrogen compounds like ammonia that plants can absorb.
91. What is 'Denitrification' in the nitrogen cycle?
Correct Answer: b) The microbial conversion of soil nitrates back into nitrogen gas, releasing it into the atmosphere
Explanation:
Denitrification is performed by denitrifying bacteria in anaerobic conditions, completing the nitrogen cycle by returning N2 gas to the atmosphere.
92. What is 'Trophic Level' in an ecosystem?
Correct Answer: b) The specific hierarchical position an organism occupies in a food chain or food web
Explanation:
Trophic levels categorize organisms by their feeding relationships, starting from primary producers (plants) up through primary, secondary, and tertiary consumers.
93. According to the 'Ten Percent Law' of energy transfer in ecology, approximately how much energy is passed on from one trophic level to the next higher level?
Correct Answer: b) 10 percent
Explanation:
Lindeman's Ten Percent Law states that when energy is passed in an ecosystem from one trophic level to the next, only about 10% of the energy is stored as biomass, with the rest lost as metabolic heat.
94. Why are energy pyramids always upright in natural ecosystems?
Correct Answer: a) Because energy is continuously lost as heat at each successive trophic level due to metabolic respiration
Explanation:
Due to the relentless loss of energy through metabolic heat at each trophic level (Ten Percent Law), energy pyramids can never be inverted.
95. Can an ecological pyramid of biomass be inverted in certain aquatic ecosystems?
Correct Answer: b) Yes, in open ocean ecosystems where microscopic phytoplankton have a smaller standing crop biomass than zooplankton at any given moment.
Explanation:
In some aquatic systems, producers (phytoplankton) reproduce rapidly with short lifespans, meaning their standing biomass at a snapshot in time can be less than the consumers (zooplankton) feeding on them.
96. What is an 'Inverted Pyramid of Numbers' typically observed in?
Correct Answer: b) Parasitic food chains where a single large tree supports numerous herbivorous birds, which in turn host thousands of parasites
Explanation:
In a parasitic food chain, a single producer (tree) supports many consumers, creating a pyramid of numbers that is narrow at the base and widens upward.
97. What is 'Primary Productivity' in an ecosystem?
Correct Answer: b) The rate at which radiant solar energy is converted into organic matter by photosynthetic producers (plants and algae)
Explanation:
Primary productivity measures the rate at which autotrophs synthesize organic chemical energy from solar radiation.
98. What is the difference between Gross Primary Productivity (GPP) and Net Primary Productivity (NPP)?
Correct Answer: a) NPP is GPP minus the energy lost by producers through cellular respiration.
Explanation:
GPP is total photosynthesis energy captured, and NPP is what remains available to consumers after producers expend energy on their own metabolic respiration.
99. Which biome on Earth exhibits the highest annual Net Primary Productivity per unit area?
Correct Answer: c) Tropical rainforests and coral reefs
Explanation:
Tropical rainforests and coral reefs have optimal warmth, moisture, and nutrient availability, driving extremely high rates of net primary productivity.
100. What is 'Biome' defined as in ecological classification?
Correct Answer: b) A large globally extensive community of plants and animals occupying a major habitat defined by distinct climatic conditions
Explanation:
Biomes are major regional biological communities shaped by regional climate patterns, encompassing biomes like tundra, taiga, desert, savanna, and rainforest.
101. What is 'Endemism' in biogeography?
Correct Answer: b) The ecological state of a species being native to and restricted to a single defined geographic location or island
Explanation:
Endemic species are unique to a specific geographic region, such as an island, mountain range, or isolated habitat, making them highly vulnerable to extinction if disturbed.
