1. An expanding population with high biotic potential typically displays which type of age pyramid?
Correct Answer: A (Triangular age pyramid)
A growing/expanding population has a high percentage of pre-reproductive individuals, yielding a broad-based triangular pyramid. Stable populations are bell-shaped, and declining populations are urn-shaped.
A growing/expanding population has a high percentage of pre-reproductive individuals, yielding a broad-based triangular pyramid. Stable populations are bell-shaped, and declining populations are urn-shaped.
2. If 8 new fruit flies were born in a laboratory culture of 80 fruit flies during a week, the per capita birth rate is:
Correct Answer: A (0.1 offspring per fruit fly per week)
Per capita birth rate = (Number of new births) / (Initial population size) = 8 / 80 = 0.1 offspring per fly per week.
Per capita birth rate = (Number of new births) / (Initial population size) = 8 / 80 = 0.1 offspring per fly per week.
3. Which parameter does NOT contribute to an increase in population density (N)?
Correct Answer: C (Emigration (E))
Population density increases via Natality (B) and Immigration (I), while it decreases via Mortality (D) and Emigration (E): N(t+1) = N(t) + [(B + I) – (D + E)].
Population density increases via Natality (B) and Immigration (I), while it decreases via Mortality (D) and Emigration (E): N(t+1) = N(t) + [(B + I) – (D + E)].
4. When resources in a habitat are limiting, population growth exhibits an S-shaped curve termed:
Correct Answer: B (Logistic growth)
Verhulst-Pearl logistic growth reflects resource limitation and carrying capacity (K), producing a sigmoid (S-shaped) curve represented by dN/dt = rN[(K – N)/K].
Verhulst-Pearl logistic growth reflects resource limitation and carrying capacity (K), producing a sigmoid (S-shaped) curve represented by dN/dt = rN[(K – N)/K].
5. In the logistic growth equation dN/dt = rN[(K – N)/K], the term (K – N)/K represents:
Correct Answer: B (Environmental resistance)
The factor (K – N)/K reflects the environmental resistance that slows population growth as density (N) approaches carrying capacity (K).
The factor (K – N)/K reflects the environmental resistance that slows population growth as density (N) approaches carrying capacity (K).
6. The prickly pear cactus introduced into Australia in the early 1920s was brought under control by introducing:
Correct Answer: A (A cactus-feeding moth)
The invasive prickly pear cactus overran millions of hectares until its natural co-evolved predator, a cactus-feeding moth, was introduced as a biocontrol agent.
The invasive prickly pear cactus overran millions of hectares until its natural co-evolved predator, a cactus-feeding moth, was introduced as a biocontrol agent.
7. When the predatory starfish Pisaster was experimentally removed from an enclosed intertidal rocky area, what occurred within a year?
Correct Answer: B (More than 10 species became extinct)
Robert Paine’s removal of the keystone predator Pisaster led to unchecked competition among prey species, driving over 10 species to local extinction.
Robert Paine’s removal of the keystone predator Pisaster led to unchecked competition among prey species, driving over 10 species to local extinction.
8. Gause’s Competitive Exclusion Principle states that:
Correct Answer: B (Two closely related competing species cannot coexist indefinitely)
Gause’s principle states that two species competing for identical limiting resources cannot coexist; the inferior competitor is eventually eliminated.
Gause’s principle states that two species competing for identical limiting resources cannot coexist; the inferior competitor is eventually eliminated.
9. MacArthur showed that five closely related species of warblers coexisted on the same spruce tree by:
Correct Answer: B (Resource partitioning)
MacArthur demonstrated resource partitioning: warblers avoided direct competitive exclusion by foraging in distinct micro-zones of the same tree.
MacArthur demonstrated resource partitioning: warblers avoided direct competitive exclusion by foraging in distinct micro-zones of the same tree.
10. The female wasp and fig tree interaction, where the wasp pollinates the inflorescence while using the fruit for oviposition, is an example of:
Correct Answer: C (Mutualism with tight co-evolution)
The fig provides egg-laying sites and developing seeds as nourishment for wasp larvae, while the wasp ensures obligate pollination (one-to-one mutualism).
The fig provides egg-laying sites and developing seeds as nourishment for wasp larvae, while the wasp ensures obligate pollination (one-to-one mutualism).
11. The Mediterranean orchid Ophrys employs sexual deceit to achieve pollination by:
Correct Answer: B (Petal mimics a female bee)
One petal of Ophrys closely resembles a female bee in size, coloration, and markings. Male bees “pseudocopulate” with the petal, transferring pollen.
One petal of Ophrys closely resembles a female bee in size, coloration, and markings. Male bees “pseudocopulate” with the petal, transferring pollen.
12. An epiphytic orchid growing on a mango branch, and barnacles growing on the back of a whale, represent:
Correct Answer: A (Commensalism)
In commensalism, one species benefits (orchid/barnacle gets physical support and feeding currents) while the host (mango tree/whale) is neither harmed nor benefited.
In commensalism, one species benefits (orchid/barnacle gets physical support and feeding currents) while the host (mango tree/whale) is neither harmed nor benefited.
13. The interaction where one species is harmed while the other is completely unaffected (-, 0), as seen in Penicillium inhibiting bacterial growth, is:
Correct Answer: C (Amensalism)
Amensalism is an ecological interaction in which one population is inhibited or destroyed while the other remains unaffected (e.g., Penicillium mold producing penicillin).
Amensalism is an ecological interaction in which one population is inhibited or destroyed while the other remains unaffected (e.g., Penicillium mold producing penicillin).
14. The parasitic plant Cuscuta (dodder) lacks chlorophyll and derives nourishment from host plants by using specialized root structures called:
Correct Answer: B (Haustoria)
Cuscuta is a total stem parasite that inserts modified peg-like roots called haustoria into the vascular bundles of the host plant to absorb nutrients and water.
Cuscuta is a total stem parasite that inserts modified peg-like roots called haustoria into the vascular bundles of the host plant to absorb nutrients and water.
15. Brood parasitism in birds, where the parasitic bird lays eggs in the host nest, is famously exhibited between:
Correct Answer: A (Cuckoo and Crow)
The cuckoo lays eggs in a crow’s nest. The eggs have co-evolved to match the crow’s eggs in size and color, avoiding detection and rejection.
The cuckoo lays eggs in a crow’s nest. The eggs have co-evolved to match the crow’s eggs in size and color, avoiding detection and rejection.
16. The Abingdon tortoise in the Galapagos Islands became extinct within a decade after goats were introduced on the island, because of:
Correct Answer: B (Greater browsing efficiency of the goats)
Goats had much higher grazing efficiency, consuming vegetation rapidly and outcompeting the slow-moving tortoises for limiting food resources.
Goats had much higher grazing efficiency, consuming vegetation rapidly and outcompeting the slow-moving tortoises for limiting food resources.
17. Vertical distribution of different species occupying different levels in an ecosystem (e.g., trees, shrubs, and herbs in a forest) is called:
Correct Answer: B (Stratification)
Stratification is the vertical arrangement of vegetation layers: canopy trees occupy top strata, shrubs form the middle layer, and herbs/grasses form the ground layer.
Stratification is the vertical arrangement of vegetation layers: canopy trees occupy top strata, shrubs form the middle layer, and herbs/grasses form the ground layer.
18. Net Primary Productivity (NPP) is related to Gross Primary Productivity (GPP) and Respiration loss (R) by the formula:
Correct Answer: A (NPP = GPP – R)
GPP is the total rate of organic matter synthesis during photosynthesis. NPP is the biomass available to heterotrophs after accounting for autotrophic respiration (R).
GPP is the total rate of organic matter synthesis during photosynthesis. NPP is the biomass available to heterotrophs after accounting for autotrophic respiration (R).
19. What is the total annual net primary productivity of the entire biosphere, and what proportion is contributed by the oceans?
Correct Answer: B (170 billion tons total; 55 billion tons from oceans)
Annual net primary productivity of the biosphere is approx 170 billion tons dry weight; oceans account for only 55 billion tons due to light and nutrient limitations.
Annual net primary productivity of the biosphere is approx 170 billion tons dry weight; oceans account for only 55 billion tons due to light and nutrient limitations.
20. The process by which water-soluble inorganic nutrients seep down into the soil horizons and precipitate as unavailable salts is called:
Correct Answer: C (Leaching)
Leaching is the downward percolation of water-soluble inorganic nutrients into deeper soil layers where they become unavailable to plant roots.
Leaching is the downward percolation of water-soluble inorganic nutrients into deeper soil layers where they become unavailable to plant roots.
21. The enzymatic degradation of detritus into simpler inorganic substances by bacterial and fungal enzymes is termed:
Correct Answer: B (Catabolism)
Catabolism during decomposition is carried out by extracellular fungal and bacterial enzymes breaking complex detritus into simple inorganic compounds.
Catabolism during decomposition is carried out by extracellular fungal and bacterial enzymes breaking complex detritus into simple inorganic compounds.
22. Decomposition rate is significantly slower when detritus is rich in:
Correct Answer: B (Lignin and Chitin)
Decomposition is slower if detritus contains structural polymers like lignin and chitin, whereas it proceeds faster with detritus rich in nitrogen and soluble sugars.
Decomposition is slower if detritus contains structural polymers like lignin and chitin, whereas it proceeds faster with detritus rich in nitrogen and soluble sugars.
23. What percentage of incident Photosynthetically Active Radiation (PAR) is captured by autotrophic plants for photosynthesis?
Correct Answer: B (2 to 10%)
Less than 50% of incident solar radiation is PAR, and photosynthetic plants capture only 2–10% of this PAR to sustain the trophic energy pyramid.
Less than 50% of incident solar radiation is PAR, and photosynthetic plants capture only 2–10% of this PAR to sustain the trophic energy pyramid.
24. In a terrestrial ecosystem, the major conduit for energy flow is the:
Correct Answer: B (Detritus Food Chain (DFC))
In terrestrial biomes, a much larger fraction of energy flows through the Detritus Food Chain than through the Grazing Food Chain. In aquatic biomes, GFC is the major conduit.
In terrestrial biomes, a much larger fraction of energy flows through the Detritus Food Chain than through the Grazing Food Chain. In aquatic biomes, GFC is the major conduit.
25. Lindeman’s 10 percent energy transfer law dictates that when energy passes from one trophic level to the next higher level:
Correct Answer: B (Only 10% is stored as biomass)
Only ~10% of the energy at one trophic level is converted into new biomass at the next level, limiting food chains to 3–5 trophic levels.
Only ~10% of the energy at one trophic level is converted into new biomass at the next level, limiting food chains to 3–5 trophic levels.
26. Which ecological pyramid is ALWAYS upright and can NEVER be inverted in any ecosystem?
Correct Answer: C (Pyramid of Energy)
The pyramid of energy is always upright because energy is lost as metabolic heat at each successive trophic level according to the Second Law of Thermodynamics.
The pyramid of energy is always upright because energy is lost as metabolic heat at each successive trophic level according to the Second Law of Thermodynamics.
27. The pyramid of biomass in an open sea/ocean ecosystem is inverted because:
Correct Answer: B (Standing crop biomass of phytoplankton is smaller)
Phytoplankton reproduce rapidly and have high turnover rates, supporting a much larger biomass of zooplankton and predatory fishes at any given point.
Phytoplankton reproduce rapidly and have high turnover rates, supporting a much larger biomass of zooplankton and predatory fishes at any given point.
28. The pyramid of numbers for a single large oak or banyan tree supporting numerous herbivorous birds and parasites is:
Correct Answer: B (Inverted)
A single primary producer (1 tree) supports hundreds of fruit-eating birds, which in turn support thousands of ectoparasites (lice, ticks), making the pyramid of numbers inverted.
A single primary producer (1 tree) supports hundreds of fruit-eating birds, which in turn support thousands of ectoparasites (lice, ticks), making the pyramid of numbers inverted.
29. The standing state of an ecosystem refers to:
Correct Answer: B (Amount of inorganic nutrients in soil)
Standing state is the pool of inorganic nutrients (such as carbon, nitrogen, phosphorus, calcium) present in the soil/abiotic environment at a given time. Standing crop refers to living biomass.
Standing state is the pool of inorganic nutrients (such as carbon, nitrogen, phosphorus, calcium) present in the soil/abiotic environment at a given time. Standing crop refers to living biomass.
30. Robert Costanza and his colleagues estimated the average annual price tag of fundamental global ecosystem services to be approximately:
Correct Answer: B (US $33 trillion)
Costanza and colleagues valued global ecosystem services at roughly US $33 trillion per year, nearly twice the global gross national product (GNP) of US $18 trillion at the time.
Costanza and colleagues valued global ecosystem services at roughly US $33 trillion per year, nearly twice the global gross national product (GNP) of US $18 trillion at the time.
31. Among the total cost of fundamental ecosystem services, soil formation accounts for roughly what percentage?
Correct Answer: C (50%)
Soil formation accounts for about 50% of the total value of global ecosystem services, while recreation and nutrient cycling account for less than 10% each.
Soil formation accounts for about 50% of the total value of global ecosystem services, while recreation and nutrient cycling account for less than 10% each.
32. Who popularized the term ‘Biodiversity’ to describe the combined diversity at all levels of biological organization?
Correct Answer: B (Edward Wilson)
Sociobiologist Edward Wilson popularized the term ‘biodiversity’ to describe collective diversity across genetic, species, and ecological levels.
Sociobiologist Edward Wilson popularized the term ‘biodiversity’ to describe collective diversity across genetic, species, and ecological levels.
33. According to Robert May’s conservative and scientifically sound global estimate, the total number of species on Earth is approximately:
Correct Answer: B (7 million)
While IUCN listed slightly more than 1.5 million named species, Robert May’s global statistical estimate placed total planetary species richness at around 7 million.
While IUCN listed slightly more than 1.5 million named species, Robert May’s global statistical estimate placed total planetary species richness at around 7 million.
34. Insects comprise what proportion of all recorded animal species on Earth?
Correct Answer: C (More than 70%)
Insects are the most species-rich taxonomic group, constituting over 70% of all animal species cataloged on Earth.
Insects are the most species-rich taxonomic group, constituting over 70% of all animal species cataloged on Earth.
35. Although India covers only 2.4 percent of the world’s land area, its share of global species diversity is an impressive:
Correct Answer: B (8.1%)
India contains 8.1% of global species diversity across its 2.4% land area, qualifying it as one of the world’s 12 mega-diversity countries.
India contains 8.1% of global species diversity across its 2.4% land area, qualifying it as one of the world’s 12 mega-diversity countries.
36. What general pattern of biodiversity is observed as one moves from the Equator toward the polar regions?
Correct Answer: B (Species diversity decreases progressively)
With few exceptions, tropics harbor more species than temperate or polar zones due to stable tropical climates, more solar energy, and longer evolutionary time without major glaciations.
With few exceptions, tropics harbor more species than temperate or polar zones due to stable tropical climates, more solar energy, and longer evolutionary time without major glaciations.
37. The mathematical species-area relationship established by Alexander von Humboldt is represented logarithmically as:
Correct Answer: A (log S = log C + Z log A)
On a log scale, the rectangular hyperbola relationship S = C(A^Z) becomes linear: log S = log C + Z log A, where S = species richness, A = area, Z = slope (regression coefficient), and C = Y-intercept.
On a log scale, the rectangular hyperbola relationship S = C(A^Z) becomes linear: log S = log C + Z log A, where S = species richness, A = area, Z = slope (regression coefficient), and C = Y-intercept.
38. When analyzing species-area relationships across very large areas like entire continents for birds or frugivorous mammals, the value of the slope Z ranges between:
Correct Answer: B (0.6 to 1.2)
For small local regions, Z is 0.1–0.2 regardless of taxon. Over whole continents, the regression line is much steeper, with Z values ranging from 0.6 to 1.2.
For small local regions, Z is 0.1–0.2 regardless of taxon. Over whole continents, the regression line is much steeper, with Z values ranging from 0.6 to 1.2.
39. David Tilman’s long-term outdoor ecosystem plot experiments demonstrated that:
Correct Answer: B (Plots with more species showed less variation in biomass)
Tilman showed that species-rich plots exhibited less year-to-year variation in biomass and produced higher overall yields, confirming that diversity contributes to ecosystem stability.
Tilman showed that species-rich plots exhibited less year-to-year variation in biomass and produced higher overall yields, confirming that diversity contributes to ecosystem stability.
40. In Paul Ehrlich’s ‘Rivet Popper hypothesis’, what do the rivets on the airplane wings represent?
Correct Answer: B (Keystone species)
Removing rivets from wings (extinction of keystone species) poses an immediate threat to flight safety (ecosystem integrity) compared to popping rivets from passenger seats.
Removing rivets from wings (extinction of keystone species) poses an immediate threat to flight safety (ecosystem integrity) compared to popping rivets from passenger seats.
41. The IUCN Red List (2004) documented the extinction of 784 species in the last 500 years. Which of the following is an extinct species paired correctly with its native region?
Correct Answer: B (Quagga – Africa)
Extinctions include Dodo (Mauritius), Quagga (Africa), Thylacine (Australia), Steller’s Sea Cow (Russia), and three tiger subspecies (Bali, Javan, Caspian).
Extinctions include Dodo (Mauritius), Quagga (Africa), Thylacine (Australia), Steller’s Sea Cow (Russia), and three tiger subspecies (Bali, Javan, Caspian).
42. Among the “Evil Quartet” driving current biodiversity loss, what is considered the SINGLE MOST IMPORTANT cause driving animal and plant species to extinction?
Correct Answer: A (Habitat loss and fragmentation)
Habitat destruction and breaking large habitats into small patches is the leading cause of extinction (e.g., tropical rainforests reduced from 14% to under 6% of Earth’s land).
Habitat destruction and breaking large habitats into small patches is the leading cause of extinction (e.g., tropical rainforests reduced from 14% to under 6% of Earth’s land).
43. The introduction of the Nile Perch into Lake Victoria in East Africa led to the catastrophic extinction of an ecologically unique assemblage of over 200 endemic species of:
Correct Answer: B (Cichlid fishes)
Introducing the predatory alien Nile Perch into Lake Victoria eliminated more than 200 native cichlid fish species through heavy predation and competition.
Introducing the predatory alien Nile Perch into Lake Victoria eliminated more than 200 native cichlid fish species through heavy predation and competition.
44. Which invasive alien weed introduced into India has caused extensive environmental damage and threats to native flora?
Correct Answer: D (All of the above)
Parthenium (carrot grass), Lantana, and Eichhornia (water hyacinth / “Terror of Bengal”) are destructive invasive weeds in India.
Parthenium (carrot grass), Lantana, and Eichhornia (water hyacinth / “Terror of Bengal”) are destructive invasive weeds in India.
45. Extinction of the Steller’s Sea Cow and Passenger Pigeon in recent history occurred primarily due to:
Correct Answer: B (Over-exploitation by humans)
Steller’s sea cow and passenger pigeons were driven to complete extinction within the last 500 years due to excessive over-hunting and human exploitation.
Steller’s sea cow and passenger pigeons were driven to complete extinction within the last 500 years due to excessive over-hunting and human exploitation.
46. The exploration of molecular, genetic, and species-level diversity for products of economic value is termed:
Correct Answer: C (Bioprospecting)
Bioprospecting is the systematic search for novel genes, biochemicals, and commercially valuable natural products from wild biological resources.
Bioprospecting is the systematic search for novel genes, biochemicals, and commercially valuable natural products from wild biological resources.
47. Biodiversity Hotspots are defined by which key criteria?
Correct Answer: B (High richness, high endemism, and high threat)
Biodiversity hotspots feature exceptional concentrations of endemic species undergoing accelerated habitat loss (34 hotspots identified globally).
Biodiversity hotspots feature exceptional concentrations of endemic species undergoing accelerated habitat loss (34 hotspots identified globally).
48. Which of the following is an example of Ex-situ (off-site) biodiversity conservation?
Correct Answer: C (Botanical Gardens, Zoological Parks, and Cryopreservation)
Ex-situ conservation involves protecting threatened animals and plants outside their natural habitats in controlled environments (zoos, botanical gardens, cryopreservation, seed banks).
Ex-situ conservation involves protecting threatened animals and plants outside their natural habitats in controlled environments (zoos, botanical gardens, cryopreservation, seed banks).
49. Sacred Groves are tracts of pristine forests protected due to religious beliefs and traditions. Which of the following is a famous Sacred Grove in India?
Correct Answer: D (All of the above)
Sacred groves serve as the last refuges for rare and threatened plants in the Khasi/Jaintia Hills (Meghalaya), Aravalli Hills (Rajasthan), Western Ghats, and Chanda/Bastar areas (Chhattisgarh).
Sacred groves serve as the last refuges for rare and threatened plants in the Khasi/Jaintia Hills (Meghalaya), Aravalli Hills (Rajasthan), Western Ghats, and Chanda/Bastar areas (Chhattisgarh).
50. The landmark Earth Summit on Biodiversity was held in Rio de Janeiro in 1992, followed by the World Summit on Sustainable Development (2002) in:
Correct Answer: C (Johannesburg, South Africa)
The Historic Earth Summit was held in Rio de Janeiro (1992). Ten years later in 2002, the World Summit on Sustainable Development took place in Johannesburg, where 190 countries pledged to reduce biodiversity loss.
The Historic Earth Summit was held in Rio de Janeiro (1992). Ten years later in 2002, the World Summit on Sustainable Development took place in Johannesburg, where 190 countries pledged to reduce biodiversity loss.