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Environment, Ecology and Biodiversity

139 questions

All types139Multiple choice73Multiple select24Matching26Ordering16
Question 61Question →

Which of the following biogeographic regions in India is officially designated as a global biodiversity hotspot and is notable for hosting endemic species such as the Lion-tailed Macaque?

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Answer: The Western Ghats

Answer

The Western Ghats is a global biodiversity hotspot known for endemic fauna like the Lion-tailed Macaque.
The Western Ghats region is recognized as a global biodiversity hotspot because it possesses high levels of species richness and endemism, providing habitat for species restricted to this ecological zone, such as the Lion-tailed Macaque and Nilgiri Tahr.

Step-by-Step Solution

1
Identify the designated global biodiversity hotspots present in India.
India hosts four hotspots: Western Ghats, Eastern Himalayas, Indo-Burma, and Sundaland.
Global hotspots are defined by having at least 1,500 endemic vascular plant species and losing over 70% of primary habitat.
2
Associate the specified endemic wildlife species with its native hotspot region.
The Lion-tailed Macaque (Macaca silenus) is restricted exclusively to the evergreen rainforest canopy of the Western Ghats.
Endemic species are restricted to a defined geographic location due to specialized habitat requirements.

Key Concept

Indian Biodiversity Hotspots and Endemic Wildlife
Question 62Question →

With reference to ecological diversity measurement concepts introduced by R.H. Whittaker and their relationship with spatial scale and endemism, consider the following statements:

1. Alpha diversity measures the species richness present within a specific, localized habitat or community.
2. Beta diversity quantifies the degree of species turnover or compositional change between different communities along an environmental gradient.
3. High beta diversity across a landscape typically indicates low habitat heterogeneity and low levels of regional endemism.

Which of the statements given above are correct?

Show answer & explanation

Answer: 1 and 2 only

Answer

Statements 1 and 2 only are correct.
The correct response identifies that Statements 1 and 2 are true while Statement 3 is false. Alpha diversity assesses species richness in a uniform local environment, whereas beta diversity measures species compositional change across habitats. Elevated beta diversity is associated with high ecological heterogeneity and localized adaptation, which increases the likelihood of finding endemic species uniquely adapted to specific micro-niches.

Step-by-Step Solution

1
Evaluate Statement 1 regarding Alpha Diversity.
Statement 1 is correct.
Alpha diversity represents local species richness within a single homogenous ecosystem or habitat unit.
2
Evaluate Statement 2 regarding Beta Diversity.
Statement 2 is correct.
Beta diversity measures species turnover or the rate of replacement in species composition between different habitats or along ecological gradients across a landscape.
3
Evaluate Statement 3 regarding the relationship between Beta Diversity, Habitat Heterogeneity, and Endemism.
Statement 3 is incorrect.
High beta diversity implies that different micro-habitats harbor distinct species assemblages. High species turnover reflects greater niche specialization and complex habitat heterogeneity, which directly promotes high endemism rather than low endemism.

Key Concept

Whittaker's Biodiversity Indices (Alpha, Beta, and Gamma Diversity) and Endemism Dynamics
Estimated Time:1m 30s
Question 63Question →

Evaluate the following statements regarding biogeochemical nutrient cycling and micro-organism functions in ecosystems:

Statement I: The primary reservoir pool for gaseous nutrient cycles resides in the atmosphere or hydrosphere, whereas for sedimentary nutrient cycles, the primary reservoir is located in the Earth's crust.
Statement II: Nitrosomonas and Nitrobacter are denitrifying bacteria responsible for returning elemental nitrogen gas to the atmosphere from soil nitrates.

Which of the statements given above is/are correct?

Show answer & explanation

Answer: Only Statement I is correct

Answer

Only Statement I is correct
Statement I is true because gaseous nutrient cycles maintain their major storage reservoir in the atmosphere or hydrosphere, ensuring rapid cycling and quick replacement of deficits. Sedimentary cycles store nutrients predominantly in sedimentary rocks and soil minerals, leading to much slower cycling. Statement II is false because Nitrosomonas and Nitrobacter perform nitrification (ammonia oxidation to nitrate), whereas denitrification is conducted by specialized bacteria such as Pseudomonas and Micrococcus denitrificans under anaerobic conditions.

Step-by-Step Solution

1
Analyze Statement I regarding reservoir pools of biogeochemical cycles
Gaseous nutrient cycles (e.g., Nitrogen, Carbon) have reservoirs in the atmosphere or ocean. Sedimentary nutrient cycles (e.g., Phosphorus, Calcium) have reservoirs in Earth's crustal rocks.
Statement I correctly defines the fundamental location of abiotic reservoir pools.
2
Analyze Statement II regarding the ecological role of Nitrosomonas and Nitrobacter
Nitrosomonas converts ammonia (NH3NH_3) to nitrite (NO2−NO_2^-), and Nitrobacter converts nitrite to nitrate (NO3−NO_3^-). This process is nitrification.
Statement II incorrectly classifies these organisms as denitrifying bacteria. Denitrification converts nitrates back into nitrogen gas (N2N_2) and is performed by organisms like Pseudomonas.
3
Synthesize results to select the correct evaluation
Statement I is correct and Statement II is incorrect.
Only Statement I meets scientific accuracy.

Key Concept

Classification of biogeochemical nutrient cycles (gaseous vs sedimentary) and biological steps in the nitrogen cycle.
Estimated Time:1m 15s
Question 64Question →

Regarding ecological functions, nutrient cycling, and ecological succession, which of the following statements are correct?

Select all that apply

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Answer: In sedimentary nutrient cycles, such as the phosphorus cycle, the principal reservoir pool is located in the Earth's crust rather than the atmosphere.; The pyramid of energy is always upright in all ecosystems because energy transfer between trophic levels is unidirectional and decreases at each step according to Lindeman's 10% law.

Answer

The correct statements are that sedimentary nutrient cycles have their main reservoir pool in the Earth's crust and that the pyramid of energy is always upright across all ecosystems.
The statements identifying the Earth's crust as the primary reservoir for sedimentary cycles and stating that energy pyramids are strictly upright due to thermodynamic laws are both scientifically correct.

Step-by-Step Solution

1
Evaluate the statement concerning biogeochemical reservoir pools.
Phosphorus and sulfur cycles are sedimentary cycles with main reservoirs in rocks and soil sediments of the Earth's crust.
Gaseous cycles have atmospheric/aquatic reservoirs (e.g., carbon, nitrogen), whereas sedimentary cycles rely on geological weathering.
2
Evaluate the statement regarding primary succession conditions.
Primary succession takes place on newly exposed, previously uncolonized bare substrates (like volcanic lava flows or exposed rock).
Substrates affected by forest fires already contain organic soil and propagules, characteristic of secondary succession.
3
Evaluate energy dynamics and pyramid geometry.
The energy pyramid can never be inverted because energy is lost as heat at each trophic transition according to the second law of thermodynamics and the 10% rule.
Net primary productivity sets the maximum available energy base, which declines monotonically at successive consumer levels.
4
Evaluate the distinction between autogenic and allogenic succession.
Autogenic succession is brought about by the living vegetation itself changing soil organic matter, light availability, and moisture.
External geological or meteorological events induce allogenic succession.

Key Concept

Classification of Biogeochemical Cycles, Energy Flow Dynamics, and Types of Ecological Succession
Question 65Question →

Which layer of Earth's atmosphere contains the natural ozone concentration responsible for absorbing the majority of harmful solar ultraviolet-B (UV-B) radiation?

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Answer: Stratosphere

Answer

Stratosphere
The stratosphere contains about 90% of Earth's atmospheric ozone, forming the stratospheric ozone layer. This layer acts as a natural protective shield by filtering harmful solar ultraviolet (UV-B) radiation before it reaches the ground.

Step-by-Step Solution

1
Identify atmospheric layers and ozone distribution
Ozone (O3O_3) is present in small amounts throughout the atmosphere, but its concentration peaks between 15 km and 35 km altitude.
Solar ultraviolet radiation breaks down oxygen molecules in this specific region, leading to ozone creation and equilibrium.
2
Match altitude range to the correct atmospheric layer
The region between ~10 km and 50 km above Earth's surface is the stratosphere.
The stratospheric ozone layer absorbs 97–99% of medium-frequency ultraviolet light from the Sun.

Key Concept

Stratospheric Ozone Layer
Question 66Question →

Consider the following statements regarding statutory authorities and constitutional mandates for environmental protection in India:

Statement I: The National Biodiversity Authority (NBA) is a statutory body established directly under the administrative provisions of the Environment (Protection) Act, 1986.
Statement II: Article 48A of the Directive Principles of State Policy enjoins the State to protect and improve the environment and safeguard forests and wildlife.
Statement III: The Central Ground Water Authority (CGWA) was constituted as a statutory authority under the provisions of the Environment (Protection) Act, 1986.

Which of the statements given above are correct?

Show answer & explanation

Answer: Only Statement II and Statement III are correct

Answer

Only Statement II and Statement III are correct.
The correct response identifies that Statement II and Statement III are true while Statement I is false. Article 48A was added to Directive Principles of State Policy via the 42nd Amendment Act in 1976. The Central Ground Water Authority (CGWA) was established under Section 3(3) of the Environment (Protection) Act, 1986. Conversely, the National Biodiversity Authority (NBA) derives its statutory authority from the Biological Diversity Act, 2002.

Step-by-Step Solution

1
Evaluate Statement I regarding the establishing statute for the National Biodiversity Authority (NBA).
The NBA is an autonomous statutory body established in 2003 to implement India's Biological Diversity Act, 2002. It was not established under the Environment (Protection) Act, 1986. Thus, Statement I is incorrect.
Identify the specific parent statute governing statutory environmental bodies in India.
2
Evaluate Statement II regarding constitutional provisions for environmental protection.
Article 48A of the Constitution of India mandates that 'The State shall endeavour to protect and improve the environment and to safeguard the forests and wild life of the country.' It was inserted into Part IV by the 42nd Amendment Act, 1976. Thus, Statement II is correct.
Verify constitutional amendments and Directive Principles of State Policy related to ecology.
3
Evaluate Statement III regarding the statutory origin of the Central Ground Water Authority (CGWA).
The Central Ground Water Authority was constituted under sub-section (3) of Section 3 of the Environment (Protection) Act, 1986, for the purpose of regulation and control of groundwater development and management. Thus, Statement III is correct.
Recognize bodies created specifically using delegated power under Section 3(3) of the Environment (Protection) Act, 1986.

Key Concept

Statutory basis of environmental bodies and constitutional provisions in India
Estimated Time:1m 30s
Question 67Question →

Endemism and biodiversity hotspots represent key concepts in conservation biology and biogeography. Regarding the evolutionary classification of endemic species and global biodiversity hotspot criteria, which of the following statements are correct?

Select all that apply

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Answer: Palaeoendemic species are phylogenetically ancient lineages that were historically widespread but are currently restricted to narrow relict habitats due to environmental changes.; Neoendemic species are evolutionarily young taxa that have arisen recently through processes such as adaptive radiation or polyploidy and have not yet expanded beyond their place of origin.

Answer

Palaeoendemic species are phylogenetically ancient lineages restricted to relict habitats, and neoendemic species are evolutionarily young taxa that have arisen recently and remain localized.
The statements defining palaeoendemics and neoendemics correctly characterize the evolutionary origins of restricted species. Palaeoendemics are ancient lineages occupying shrinking relict habitats, whereas neoendemics are newly formed species that have not yet dispersed widely.

Step-by-Step Solution

1
Evaluate statements regarding evolutionary categories of endemism
Palaeoendemics are evolutionary relics that were once widespread, whereas neoendemics are recently evolved taxa (via polyploidy or speciation) with limited geographic spread. Both assertions are scientifically accurate.
Endemism is categorized by evolutionary age into palaeoendemism (ancient relict) and neoendemism (recent origin).
2
Evaluate the quantitative criteria for Norman Myers' global biodiversity hotspots
The exact quantitative threshold for vascular plant endemism is ≥1,500\geq 1,500 endemic species, combined with ≥70%\geq 70\% loss of primary natural habitat.
Stating a requirement of 2,500 endemic plant species misstates the official Conservation International / Norman Myers quantitative standard.
3
Verify the regional hotspot assignment of Indian island groups
The Nicobar Islands are part of the Sundaland hotspot, and the Andaman Islands are part of Indo-Burma. Neither is in the Western Ghats.
India hosts four recognized hotspot zones: Western Ghats, Eastern Himalayas, Indo-Burma (including Andaman Islands), and Sundaland (including Nicobar Islands).

Key Concept

Classification of Endemism and Global Biodiversity Hotspot Criteria
Question 68Question →

With reference to ecological measures of biodiversity and species turnover, evaluate the following statements:

1. Alpha diversity measures the overall species diversity across an entire landscape or large geographical region containing multiple ecosystems.
2. Beta diversity quantifies the rate of change or turnover in species composition between different habitats or along environmental gradients.
3. Regions exhibiting high beta diversity typically display low levels of localized endemism because species freely migrate across habitat boundaries.

Which of the statement(s) given above is/are correct?

Show answer & explanation

Answer: 2 only

Answer

Statement 2 is the only correct statement.
The statement specifying '2 only' is correct. Beta diversity measures the differentiation of species composition across distinct habitats. Statement 1 is false because landscape-level diversity is defined as gamma diversity. Statement 3 is false because steep ecological gradients and high beta diversity promote habitat isolation and narrow geographical distribution, resulting in high levels of endemism.

Step-by-Step Solution

1
Evaluate Statement 1 regarding Alpha diversity
Statement 1 is incorrect.
Alpha diversity (α \alpha-diversity) refers to the species richness within a single uniform ecosystem or local habitat, whereas diversity across an entire landscape or regional scale is termed Gamma diversity (γ \gamma-diversity).
2
Evaluate Statement 2 regarding Beta diversity
Statement 2 is correct.
Beta diversity (β \beta-diversity) represents the proportion of species turnover or community differentiation between adjacent ecosystems along an environmental or spatial gradient.
3
Evaluate Statement 3 regarding Beta diversity and Endemism
Statement 3 is incorrect.
High beta diversity indicates sharp changes in species composition between habitats due to niche specialization and environmental barriers, which directly correlates with high localized endemism rather than low endemism.

Key Concept

Whittaker's Biodiversity Indices (Alpha, Beta, Gamma Diversity) and Endemism Mechanics
Question 69Question →

Match the climate and atmospheric processes in List-I with their corresponding physical mechanisms or environmental impacts in List-II:

Click a left item, then click its matching right item

Items

Steric Sea Level Rise
Ice-Albedo Positive Feedback
Stratospheric Cooling
Heterogeneous Ozone Catalysis

Matches

Show answer & explanation

Answer

Steric Sea Level Rise corresponds to the thermal expansion of seawater driven by heat absorption; Ice-Albedo Positive Feedback corresponds to accelerated warming as reflective ice turns to dark ocean water; Stratospheric Cooling corresponds to thermal contraction in upper layers due to longwave trapping in the troposphere; and Heterogeneous Ozone Catalysis corresponds to rapid conversion of chlorine reservoir species on polar stratospheric cloud particles.
Each item in List-I correctly matches its defining physical or chemical mechanism in List-II based on established atmospheric science: Steric Sea Level Rise is caused by thermal ocean expansion; Ice-Albedo Feedback amplifies warming via reflectivity loss; Stratospheric Cooling is a signature of tropospheric greenhouse trapping; and Heterogeneous Ozone Catalysis occurs on polar stratospheric cloud particle surfaces.

Step-by-Step Solution

1
Analyze Steric Sea Level Rise
Steric rise is driven by thermal expansion (density reduction of water as temperature rises), matching the thermal expansion description.
Sea level rise has two main components: eustatic (ice melt) and steric (thermal expansion).
2
Analyze Ice-Albedo Positive Feedback
Decreasing ice cover lowers surface albedo, absorbing more solar radiation and magnifying temperature increases.
Albedo measures surface reflectivity; replacing high-albedo ice (0.8−0.90.8-0.9) with low-albedo ocean (0.060.06) creates a self-reinforcing warming loop.
3
Analyze Stratospheric Cooling
Increased greenhouse gases trap heat in the troposphere, reducing infrared flux reaching the stratosphere and causing it to cool.
Stratospheric cooling is a primary fingerprint distinguishing greenhouse-driven warming from solar irradiance changes.
4
Analyze Heterogeneous Ozone Catalysis
Polar Stratospheric Clouds (PSCs) provide solid surfaces for reactions converting inactive chlorine reservoirs into photolytically active forms.
Gas-phase reactions alone are too slow to account for Antarctic spring ozone hole formation; surface reactions on PSC particles are essential.

Key Concept

Atmospheric thermodynamic feedbacks and stratospheric chemistry mechanisms associated with climate change and ozone depletion.
Question 70Question →

Ecological systems are structured hierarchically, where each successive level exhibits emergent properties not present at lower levels. Arrange the following levels of ecological organization in strict ascending order of structural complexity and spatial scale, from the most fundamental biological unit to the global system.

Drag items to arrange them in the correct order

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Answer

The correct ascending sequence of ecological hierarchy is: Individual Organism → Population → Biological Community → Ecosystem → Biome → Biosphere.
The structural complexity of ecological organization increases progressively as new emergent properties are added at each level. It starts with the Individual Organism (physiological unit), aggregates into a single-species Population (demographic unit), expands into a multi-species Biological Community (biotic interactions), integrates non-living physical components to form an Ecosystem (energy flow and nutrient cycling), groups into regional Biomes (climatic-vegetational zones), and culminates in the planetary Biosphere.

Step-by-Step Solution

1
Identify the base unit of ecological study.
The Individual Organism represents the single biological entity and physiological unit.
Lower sub-individual levels (molecules, cells, tissues, organs) fall under cell biology and physiology rather than ecological systems.
2
Group individuals of the same species.
A Population is formed by individuals of one species sharing a specific area.
Populations introduce demographic and evolutionary parameters such as birth rate, mortality rate, and gene flow.
3
Combine multiple interacting species populations.
A Biological Community consists of all biotic populations interacting in an area.
Communities focus purely on biotic interactions (predation, competition, mutualism) without integrating abiotic cycles.
4
Integrate biotic community with non-living physical factors.
An Ecosystem is created by combining the biotic community with abiotic factors.
Ecosystems introduce energy flow, trophic dynamics, and biogeochemical nutrient cycling.
5
Scale ecosystems to regional climatic zones.
A Biome is a large regional grouping of ecosystems defined by climate and vegetation.
Biomes (e.g., Tropical Rainforest, Tundra) span large geographical regions sharing similar macroscopic environmental conditions.
6
Extend to the global ecological system.
The Biosphere encompasses all ecosystems and biomes on Earth.
It represents the sum total of all life-supporting zones across land, water, and air.

Key Concept

Levels of Ecological Hierarchy and Emergent Properties
Question 71Question →

Match each biodiversity conservation strategy or site in List-I with its correct conservation classification and defining feature in List-II.

Click a left item, then click its matching right item

Items

Biosphere Reserve
Botanical Garden
Cryopreservation
Sacred Grove

Matches

Show answer & explanation

Answer

Biosphere Reserve matches with in-situ ecosystem conservation divided into core, buffer, and transition zones; Botanical Garden matches with ex-situ cultivation and display of live plants; Cryopreservation matches with ex-situ ultra-low temperature storage of genetic material; Sacred Grove matches with in-situ community protection of natural forest patches through cultural traditions.
In-situ conservation protects wild species within their natural habitats and ecosystems (e.g., Biosphere Reserves with core-buffer-transition zones, and Sacred Groves preserved by indigenous communities). Ex-situ conservation safeguards organisms outside their natural environments using specialized facilities or technology (e.g., Botanical Gardens displaying cultivated plants, and Cryopreservation preserving genetic stock at ultra-low temperatures).

Step-by-Step Solution

1
Classify Biosphere Reserve based on location and scope.
Biosphere Reserves protect species in their natural habitats (in-situ) along with local communities across structured zones.
On-site habitat preservation defines in-situ strategy.
2
Classify Botanical Garden based on location and function.
Botanical Gardens grow plants outside their natural habitats for research and education (ex-situ).
Off-site management of living species is an ex-situ conservation method.
3
Classify Cryopreservation techniques.
Cryopreservation stores biological samples in liquid nitrogen in laboratory conditions (ex-situ).
Preserving genetic samples under controlled artificial conditions is an ex-situ strategy.
4
Classify Sacred Groves based on protection mechanism.
Sacred Groves maintain pristine forest patches in their original natural locations (in-situ).
Community-led protection of wild natural habitats constitutes in-situ conservation.

Key Concept

Classification of Biodiversity Conservation into In-situ (on-site natural habitat protection) and Ex-situ (off-site artificial facility preservation).
Question 72Question →

Match List-I (International Environmental Agreement/Convention) with List-II (Primary Objective/Focus Area) and select the correct matching pair combinations:

Click a left item, then click its matching right item

Items

Ramsar Convention
Bonn Convention (CMS)
Basel Convention
Vienna Convention

Matches

Show answer & explanation

Answer

Ramsar Convention matches with Conservation and wise use of wetlands; Bonn Convention (CMS) matches with Conservation of migratory species of wild animals throughout their range; Basel Convention matches with Control of transboundary movements of hazardous wastes and their disposal; Vienna Convention matches with Framework for international efforts to protect the ozone layer.
The Ramsar Convention directly addresses wetland conservation and wise use; the Bonn Convention (CMS) addresses migratory fauna conservation across geographic ranges; the Basel Convention restricts and regulates hazardous waste movements across borders; and the Vienna Convention establishes the framework protocol for stratospheric ozone layer protection.

Step-by-Step Solution

1
Identify the primary focus of the Ramsar Convention.
Ramsar Convention (adopted in 1971 in Ramsar, Iran) is dedicated to the conservation and wise use of wetlands.
Establishing correct pairing for wetland ecosystem protection.
2
Identify the mandate of the Bonn Convention.
The Bonn Convention (Convention on the Conservation of Migratory Species of Wild Animals - CMS) targets migratory species habitat protection and range management.
Distinguishing species-specific biodiversity agreements from waste or chemical treaties.
3
Determine the focus area of the Basel Convention.
The Basel Convention specifically governs transboundary movements of hazardous waste and their disposal.
Differentiating chemical and waste treaties from biodiversity conventions.
4
Determine the scope of the Vienna Convention.
The Vienna Convention (1985) serves as the overarching framework agreement for global ozone layer protection initiatives.
Identifying atmosphere/climate-related international agreements.

Key Concept

Core mandates and primary objectives of major international multilateral environmental agreements (MEAs).
Question 73Question →

Which unit of measurement is standardly used to express the total column concentration or abundance of ozone in Earth's atmosphere?

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Answer: Dobson Unit (DUDU)

Answer

The Dobson Unit (DUDU) is the standard unit for measuring atmospheric column ozone abundance.
The Dobson Unit (DUDU) is internationally recognized as the standard metric for total column ozone. An average atmospheric ozone layer thickness is approximately 300 DU300\text{ DU}, which equates to a compressed pure ozone layer of 3 mm3\text{ mm} at STPSTP.

Step-by-Step Solution

1
Identify the physical quantity being measured.
The total amount of ozone present in a vertical column of the atmosphere.
The question asks for the specific unit representing column ozone abundance.
2
Recall the standard meteorological and environmental metric for column ozone.
One Dobson Unit (1 DU1\text{ DU}) corresponds to a layer of pure ozone 0.01 mm0.01\text{ mm} thick at standard temperature and pressure (STPSTP).
This metric standardizes measurements from ground-based spectrophotometers and satellite sensors.

Key Concept

Measurement of Total Atmospheric Column Ozone
Estimated Time:45s
Question 74Question →

Match the environmental terms and metrics in List-I with their corresponding atmospheric characteristics or definitions in List-II:

Click a left item, then click its matching right item

Items

Global Warming Potential (GWP)
Polar Stratospheric Clouds (PSCs)
Ozone Depletion Potential (ODP)
Radiative Forcing

Matches

Show answer & explanation

Answer

Global Warming Potential (GWP) pairs with the measure of heat trapped relative to carbon dioxide; Polar Stratospheric Clouds (PSCs) pair with high-altitude polar clouds providing surfaces for chlorine activation; Ozone Depletion Potential (ODP) pairs with relative measure of ozone destruction standardized against CFC-11; and Radiative Forcing pairs with net change in Earth's energy balance.
Each item in List-I corresponds directly to its standard environmental science definition: Global Warming Potential evaluates heat-trapping relative to CO2\text{CO}_2; Polar Stratospheric Clouds provide heterogeneous reaction sites for polar chlorine activation; Ozone Depletion Potential measures stratospheric destruction efficiency compared to CFC-11; and Radiative Forcing expresses net changes in Earth's energy balance.

Step-by-Step Solution

1
Identify the definition of Global Warming Potential (GWP)
GWP is a normalized index comparing the radiative effect of a greenhouse gas to CO2\text{CO}_2.
By definition, CO2\text{CO}_2 serves as the baseline gas with a GWP of 1.
2
Identify the function of Polar Stratospheric Clouds (PSCs)
PSCs facilitate chemical reactions in extreme polar cold that release active chlorine compounds.
These heterogeneous cloud surface reactions are essential to polar ozone hole formation during spring.
3
Identify the definition of Ozone Depletion Potential (ODP)
ODP measures ozone degradation efficiency relative to CFC-11.
CFC-11 is the internationally accepted standard substance assigned an ODP of 1.0.
4
Identify the definition of Radiative Forcing
Radiative forcing quantifies the energy imbalance in Earth's climate system.
Positive forcing leads to surface warming, while negative forcing causes cooling.

Key Concept

Key Metrics and Atmospheric Processes in Climate Science and Ozone Layer Depletion
Question 75Question →

Regarding biogeographical endemism, palaeo-endemism, and the precise spatial boundaries of global biodiversity hotspots overlapping Indian territory, which of the following statements are correct?

Select all that apply

Show answer & explanation

Answer: Palaeo-endemic species represent phylogenetically ancient lineages that were once widespread but are now geographically restricted to specific refugia like the Western Ghats.; The Sundaland biodiversity hotspot extends into Indian territory to include the Nicobar Islands, hosting endemic fauna such as the Nicobar megapode.

Answer

The statements confirming that palaeo-endemics are ancient lineages restricted to refugia and that the Sundaland hotspot encompasses the Nicobar Islands are correct.
Palaeo-endemics are relict taxa preserved in stable microclimatic refugia such as the Western Ghats. Additionally, the Sundaland hotspot geographically incorporates the Nicobar Islands, where distinct endemic species like the Nicobar megapode reside.

Step-by-Step Solution

1
Analyze evolutionary concepts of endemism
Palaeo-endemism correctly describes ancient species whose historical range has shrunk to specific refugia, whereas neo-endemism involves recently evolved species.
Differentiates ecological age and evolutionary history of endemic flora and fauna.
2
Delineate spatial limits of Indian biodiversity hotspots
The Indo-Burma hotspot covers Northeastern India south of the Brahmaputra River. The Himalayan hotspot covers regions north of the Brahmaputra including Sikkim and Arunachal Pradesh. The Sundaland hotspot covers the Nicobar Islands.
Prevents biogeographical misattribution between adjacent hotspot regions.
3
Evaluate conservation status categorization metrics
Endemic status describes spatial distribution, whereas IUCN Red List criteria evaluate demographic factors, population reduction, and habitat loss.
Disentangles ecological concepts of endemism from formal conservation risk assessment categories.

Key Concept

Hotspot Biogeography and Endemism Mechanics
Question 76Question →

Which of the following international conventions specifically adopted the binding target of achieving 'Land Degradation Neutrality' (LDN) as a core strategic objective for sustainable land management?

Show answer & explanation

Answer: United Nations Convention to Combat Desertification (UNCCD)

Answer

United Nations Convention to Combat Desertification (UNCCD)
The United Nations Convention to Combat Desertification (UNCCD) is the designated international treaty addressing land degradation, drought, and desertification. At COP 12, state parties formally endorsed Land Degradation Neutrality (LDN)—a state whereby the amount and quality of land resources necessary to support ecosystem functions remain stable or increase—as a core policy goal.

Step-by-Step Solution

1
Identify the core objective presented in the stem.
The target objective is 'Land Degradation Neutrality' (LDN), which aims to balance land degradation with land restoration.
Recognizing the mandate of global treaties requires connecting specific ecological metrics with their governing international bodies.
2
Evaluate the primary scope of each listed environmental convention.
UNCCD addresses desertification and land degradation; CBD addresses biodiversity; UNFCCC addresses climate change; Ramsar addresses wetland ecosystems.
Differentiating the primary focus areas of the Rio Conventions and specialized treaties eliminates incorrect choices.
3
Select the governing body responsible for Land Degradation Neutrality.
The UNCCD officially adopted Land Degradation Neutrality (LDN) as a central strategic target aligned with Sustainable Development Goal 15.3.
UNCCD is the sole legally binding international agreement linking sustainable land management to environmental development.

Key Concept

Land Degradation Neutrality (LDN) under the United Nations Convention to Combat Desertification (UNCCD)
Question 77Question →

Consider the following statements regarding the process of decomposition in an ecosystem and its role in nutrient cycling:

1. Decomposition rate is significantly slower if detritus is rich in lignin and chitin, whereas it is faster if detritus is rich in nitrogen and water-soluble substances like sugars.
2. Warm and moist environmental conditions severely inhibit microbial activity, leading to slow decomposition and the accumulation of organic matter.
3. Mineralization is the step in decomposition where microbes further degrade humus to release inorganic nutrients into the soil.

Which of the statements given above are correct?

Show answer & explanation

Answer: 1 and 3 only

Answer

The statement combination '1 and 3 only' is correct.
Decomposition is a foundational ecological function that recycles nutrients bound in dead organic matter back into abiotic pools. Statement 1 accurately states chemical substrate controls: detritus rich in chitin and lignin decomposes slowly due to complex chemical bonds, while nitrogen and water-soluble sugars decay rapidly. Statement 3 correctly defines mineralization as the final microbial breakdown of humus releasing inorganic plant nutrients. Statement 2 is false because warm and moist climates accelerate microbial respiration and decay; cold and anaerobic environments are what inhibit decomposition.

Step-by-Step Solution

1
Evaluate Statement 1 regarding chemical composition of detritus
Statement 1 is correct
Structural polymers like lignin and chitin are resistant to enzymatic degradation, slowing decomposition, while nitrogenous compounds and soluble sugars are easily metabolized by decomposers.
2
Evaluate Statement 2 regarding climatic factors influencing decomposition
Statement 2 is incorrect
Warm temperatures and high moisture favor microbial metabolism and oxygen diffusion, thereby accelerating decomposition. Low temperatures and anaerobic conditions inhibit decomposition.
3
Evaluate Statement 3 regarding the definition of mineralization
Statement 3 is correct
Humification forms dark colloidal humus, which is subsequently mineralized by specific soil microbes to yield inorganic minerals (NH4+NH_4^+, PO43−PO_4^{3-}, Ca2+Ca^{2+}, etc.).

Key Concept

Factors regulating ecosystem decomposition rate and steps of nutrient mineralization
Estimated Time:1m 0s
Question 78Question →

Consider the following statements regarding ecosystem structure, ecological niches, and community boundaries:

1. An ecological niche encompasses not only the physical microhabitat occupied by a species, but also its functional role and trophic interactions within the community.
2. In open-water aquatic ecosystems, the pyramid of biomass is typically inverted because the standing crop of producers at any given moment is lower than that of primary consumers, supported by a high turnover rate of phytoplankton.
3. An ecotone represents a sharp boundary zone that consistently exhibits lower total species richness and lower population density than either of the adjoining biological communities.

Which of the statements given above are correct?

Show answer & explanation

Answer: 1 and 2 only

Answer

1 and 2 only
The correct response identifies statements 1 and 2 as true while recognizing statement 3 as false. Ecological niches integrate both spatial habitat requirements and functional community roles. In aquatic ecosystems, rapid reproduction rates of producers create an inverted biomass pyramid despite a upright energy pyramid. Conversely, ecotones exhibit increased species richness and density due to the edge effect, contradicting the claim of reduced diversity.

Step-by-Step Solution

1
Analyze Statement 1 regarding ecological niche definition.
Statement 1 is correct.
An ecological niche includes the physical space (habitat niche), functional role (trophic niche), and environmental tolerance limits of a species.
2
Analyze Statement 2 regarding biomass pyramid in aquatic ecosystems.
Statement 2 is correct.
Phytoplankton have a very short lifespan and high productivity rate (turnover), allowing a small standing crop biomass to support a larger biomass of longer-lived zooplankton and fish, resulting in an inverted pyramid of biomass.
3
Analyze Statement 3 regarding structural characteristics of an ecotone.
Statement 3 is incorrect.
An ecotone is a transition zone between two biomes (e.g., mangrove forest between terrestrial forest and marine aquatic system). Due to the 'edge effect', ecotones frequently harbor greater biodiversity, higher population densities, and specialized 'edge species' compared to neighboring communities.

Key Concept

Ecological Niche, Aquatic Pyramids of Biomass, and Edge Effect in Ecotones
Estimated Time:1m 30s
Question 79Question →

Regarding the statutory bodies and enforcement mechanisms established under National Environmental Legislation in India, which of the following statements are correct?

Select all that apply

Show answer & explanation

Answer: The Central Ground Water Authority (CGWA) was constituted under Section 3(3) of the Environment (Protection) Act, 1986.; The National Board for Wildlife (NBWL) is a statutory body constituted under the Wildlife (Protection) Act, 1972.

Answer

The correct statements are that the Central Ground Water Authority (CGWA) was constituted under the Environment (Protection) Act, 1986, and the National Board for Wildlife (NBWL) is a statutory body constituted under the Wildlife (Protection) Act, 1972.
The Central Ground Water Authority was formally constituted under Section 3(3) of the Environment (Protection) Act, 1986. Additionally, the National Board for Wildlife is a statutory body constituted under Section 5A of the Wildlife (Protection) Act, 1972. Both statements accurately describe statutory origins.

Step-by-Step Solution

1
Evaluate statutory origin of the Central Ground Water Authority (CGWA)
The CGWA was created pursuant to orders of the Supreme Court under Section 3(3) of the Environment (Protection) Act, 1986.
Verifying statutory authorization for environmental authorities in India.
2
Evaluate statutory origin of the Central Pollution Control Board (CPCB)
The CPCB was established under the Water (Prevention and Control of Pollution) Act, 1974.
Identifying the precise enacting statute for central pollution regulatory bodies.
3
Evaluate statutory origin of the National Board for Wildlife (NBWL)
The NBWL was constituted under Section 5A of the Wildlife (Protection) Act, 1972.
Checking governing legislation for national wildlife protection authorities.
4
Evaluate procedural framework governing the National Green Tribunal (NGT)
The NGT is guided by principles of natural justice and is explicitly exempt from strict adherence to the Code of Civil Procedure, 1908.
Distinguishing judicial procedure rules from natural justice mandates of specialized tribunals.

Key Concept

Statutory basis and procedural mandates of environmental regulatory bodies in India
Question 80Question →

Consider the following statements regarding the global biodiversity hotspots criteria and their regional distribution in India:

1. To qualify as a biodiversity hotspot, a region must contain at least 1,500 species of endemic vascular plants (representing >0.5% of the world's total).
2. A candidate region must have retained at least 70% of its original primary natural vegetation to demonstrate high ecological integrity.
3. Among the Indian territory regions, the Nicobar group of islands is biogeographically included under the Sundaland hotspot, whereas the Andaman Islands fall under the Indo-Burma hotspot.

Which of the statements given above are correct?

Show answer & explanation

Answer: 1 and 3 only

Answer

The correct statements are 1 and 3 only.
The correct response identifies statements 1 and 3 as true. Statement 1 accurately captures the quantitative threshold of at least 1,500 endemic vascular plant species (>0.5% of global total). Statement 3 correctly separates the Andaman Islands (Indo-Burma hotspot) from the Nicobar Islands (Sundaland hotspot). Statement 2 is false because hotspots must have lost at least 70% of primary vegetation (retaining 30% or less).

Step-by-Step Solution

1
Evaluate Statement 1 regarding Norman Myers' quantitative endemism criterion.
Statement 1 is correct. A biodiversity hotspot must contain at least 1,500 species of endemic vascular plants, which constitutes over 0.5% of the world's total vascular plant species.
Vascular plants are critical indicators of ecosystem diversity, and this strict quantitative threshold ensures only exceptionally species-rich areas qualify.
2
Evaluate Statement 2 regarding habitat loss and threat criteria.
Statement 2 is incorrect. A region must have lost at least 70% of its original primary vegetation (meaning it retains 30% or less of its original natural habitat) to qualify under the degree of threat criterion.
The hotspot designation highlights urgent conservation needs in areas under extreme human threat, not pristine intact reserves.
3
Evaluate Statement 3 regarding Indian hotspot geography.
Statement 3 is correct. Geographically and ecologically, the Nicobar Islands form part of the Sundaland hotspot (extending into South-East Asia), whereas the Andaman Islands form part of the Indo-Burma hotspot.
The two island archipelagos belong to distinct biogeographical realms despite politically being part of the same Indian Union Territory.

Key Concept

Norman Myers Biodiversity Hotspots Criteria and Indian Geographic Distribution
Estimated Time:1m 30s
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