Biodiversity and Conservation (NCERT Practice Paper)
Q1. Select true statements for 'In situ' conservation: (i) Saving the whole forest to save the tiger. (ii) Legally protected areas like National Parks. (iii) Sacred groves are an example.
Correct Answer: (a)
In situ conservation means protecting species within their natural habitats. This includes national parks, wildlife sanctuaries, and sacred groves. Saving an entire forest for a flagship species is also in situ. All are correct.
Q2. Genetic variation in the medicinal plant Rauwolfia vomitoria is an example of:
Correct Answer: (c)
Genetic diversity refers to the variation of genes within a single species. Rauwolfia vomitoria shows variation in the concentration of reserpine (an active compound) among different populations, which is a classic example of genetic diversity at the intraspecific level.
Q3. Assertion: 10,000 more hectares of rain forest will have been lost by the time you finish reading this chapter.
Reason: Tropical rain forests are being destroyed fast for cultivating soya beans.
Correct Answer: (a)
The assertion highlights the alarming rate of deforestation, and the reason correctly attributes it to agricultural expansion, such as soya bean cultivation. Both are true, and the reason explains the high rate of loss, making it a valid explanation.
Q4. The 'Evil Quartet' refers to:
Correct Answer: (b)
The 'Evil Quartet' is a term used to describe the four major causes of biodiversity loss: habitat destruction, over‑exploitation, invasive alien species, and co‑extinctions. These anthropogenic pressures are driving the current extinction crisis.
Q5. Assertion: Seed banks are a form of ex situ conservation.
Reason: Seeds of different genetic strains can be kept for long periods in them.
Correct Answer: (b)
Both statements are correct: seed banks are indeed ex situ conservation tools, and they store seeds for long durations. However, the ability to store seeds does not explain why they are classified as ex situ; they are ex situ because the conservation occurs outside the natural habitat, not because of storage duration.
Q6. Ecologists have discovered that the value of Z generally lies in the range of:
Correct Answer: (c)
For species‑area relationships at the regional scale (e.g., within a continent), the slope Z typically ranges between 0.1 and 0.2. This small value reflects a gradual increase in species richness with area, contrasting with larger slopes observed across continents.
Q7. Assertion: The number of species on earth is not precisely known.
Reason: Many taxonomic groups are more complete in temperate regions than in the tropics.
Correct Answer: (a)
Both statements are correct. The incomplete taxonomic inventory in tropical regions (where species diversity is highest) is a major reason why the total number of species remains uncertain. Hence the reason directly explains the assertion.
Q8. Regarding 'Tilman's Experiments': (i) used outdoor plots. (ii) Plots with more species showed less year-to-year variation in biomass. (iii) Increased diversity contributed to higher productivity.
Correct Answer: (a)
Tilman's experiments in outdoor plots demonstrated that higher diversity leads to greater stability (less biomass variation) and higher productivity. All three statements are correct.
Q9. Match the following for species richness in birds:
Location
No. of Bird Species
A. Colombia
(I) 1,400
B. New York
(II) 105
C. Greenland
(III) 56
D. India
(IV) 1,200
Correct Answer: (a)
Colombia has the highest bird species count (~1,400); New York has about 105; Greenland has about 56; India has around 1,200 species. Correct matching: A–I, B–II, C–III, D–IV.
Q10. Which are correct for 'Bioprospecting'? (i) Explores diversity for products of economic importance. (ii) Includes molecular and genetic levels. (iii) Leads to direct economic benefits.
Correct Answer: (a)
Bioprospecting is the exploration of biodiversity for commercially valuable products, working at molecular, genetic, and species levels. It can yield direct economic benefits, so all statements are true.
Q11. Which of the following is correct regarding 'Hotspots'? (i) They have high levels of species richness. (ii) They have high degree of endemism. (iii) There are 34 hotspots in the world.
Correct Answer: (a)
Hotspots are defined by high species richness and endemism, and they must have lost at least 70% of their original habitat. There are currently 34 identified hotspots globally, so all statements are correct.
Q12. According to the text, what percentage of all mammal species in the world face the threat of extinction?
Correct Answer: (b)
Approximately 23% of all mammal species are currently threatened with extinction. This high proportion reflects the severe impact of human activities such as habitat destruction, hunting, and climate change on mammalian populations.
Q13. Assertion: Ethical arguments for conserving biodiversity relate to our moral duty.
Reason: Every species has an intrinsic value, even if it has no economic value to us.
Correct Answer: (a)
Both the assertion and reason are correct. The ethical argument for conservation is rooted in the belief that all species have intrinsic worth, regardless of their utility to humans. This moral responsibility is a key driver for conservation efforts.
Q14. Match the following for human history (intro pages):
A. 18,000 years ago
Cave Art
B. 10,000 years ago
Agriculture
Correct Answer: (a)
Cave art dates back to about 18,000 years ago, while agriculture emerged around 10,000 years ago. Thus A corresponds to Cave Art and B to Agriculture.
Q15. In general, species diversity ______ as we move away from the equator towards the poles.
Correct Answer: (b)
Species diversity shows a latitudinal gradient: it is highest near the equator and decreases progressively towards the poles. This pattern is observed in many taxa and is attributed to factors like climate stability, productivity, and evolutionary history.
Q16. More than ______ per cent of the drugs sold in the market worldwide are derived from plants.
Correct Answer: (b)
Over 25% of prescribed drugs worldwide are derived from plants, many of which come from tropical forests. This narrow utilitarian value underscores the importance of conserving plant diversity for future pharmaceutical discoveries.
Q17. Identify correct features of 'Prokaryote' biodiversity estimations: (i) Figures are not accurately known. (ii) Conventional taxonomic methods are not suitable. (iii) Many species are not culturable under lab conditions.
Correct Answer: (a)
Prokaryotic diversity is underestimated because many cannot be cultured, conventional methods fail to detect them, and thus accurate counts are unknown. All statements are correct.
Q18. Assertion: The 'rivet popper hypothesis' is an analogy for ecosystem safety.
Reason: Rivets on the wings are more critical than rivets on the seats.
Correct Answer: (b)
Both the assertion and reason are true parts of Ehrlich's analogy, but the reason does not explain why the analogy represents ecosystem safety. The analogy as a whole (using rivets to represent species) is what illustrates the concept; the specific comparison of wing vs seat rivets is just a detail within that analogy.
Q19. Assertion: Tropical latitudes harbour more species than temperate or polar areas.
Reason: Tropical environments are less seasonal and relatively more constant.
Correct Answer: (a)
The assertion is true: tropical regions have higher species diversity. The reason is also true: tropical environments are indeed less seasonal and more constant, which promotes niche specialisation and reduces extinction risks, thus explaining the higher diversity.
Q20. The African catfish Clarias gariepinus was illegally introduced for:
Correct Answer: (c)
The African catfish Clarias gariepinus was illegally introduced into Indian waters for aquaculture purposes, to boost fish production. However, it became invasive, outcompeting native catfishes and posing a threat to local aquatic biodiversity.
Q21. Match theFollowing for Summits:
Summit
Year
A. Earth Summit
1992
B. World Summit
2002
Correct Answer: (a)
The Earth Summit (UNCED) was held in 1992, and the World Summit on Sustainable Development took place in 2002. Thus A is 1992 and B is 2002.
Q22. Match the following for fish species:
Type
No. of Species
A. Global Fishes
28,000
B. Amazon Fishes
3,000
Correct Answer: (a)
Globally, there are about 28,000 known species of fishes; the Amazon River basin alone harbours around 3,000 fish species. So A is 28,000 and B is 3,000.
Q23. Who observed the species-area relationship in South American jungles?
Correct Answer: (c)
The species‑area relationship was first documented by Alexander von Humboldt during his explorations in South America. He observed that within a region, species richness increased with the area explored, laying the foundation for biogeography.
Q24. What is the most important cause driving animals and plants to extinction?
Correct Answer: (c)
Habitat loss and fragmentation are the single most important cause of species extinction worldwide. Destruction of natural habitats, especially in tropical forests, destroys the homes of countless species and fragments populations, making them more vulnerable.
Q25. The exploration of molecular, genetic, and species-level diversity for products of economic importance is:
Correct Answer: (b)
Bioprospecting is the systematic search for valuable compounds and genes in biodiversity. It involves exploring genetic, molecular, and species diversity to discover new pharmaceuticals, enzymes, and other economically useful products.
Q26. Match the number of species in India:
Taxon
Number recorded
A. Plants
(I) 90,000 (twice of plants)
B. Animals
(II) 45,000
Correct Answer: (a)
India has nearly 45,000 species of plants and about twice that number (approximately 90,000) of animals. Thus A–II (45,000) and B–I (90,000) are correct.
Q27. There are more than ______ species of beetles known to exist.
Correct Answer: (c)
Beetles (Coleoptera) are the most diverse insect order, with over 3,00,000 described species. This makes them one of the most species-rich taxonomic groups on Earth, highlighting the vastness of insect diversity.
Q28. Match theFollowing for Z values:
Region Scale
Z value range
A. Small area (Britain plants)
0.1 to 0.2
B. Large area (Continents)
0.6 to 1.2
Correct Answer: (a)
For small geographic regions (e.g., Britain), the slope Z is low (0.1–0.2). For larger areas like continents, Z ranges from 0.6 to 1.2. Hence A–I, B–II is correct.
Q29. Initially, how many biodiversity hotspots were identified?
Correct Answer: (b)
The concept of biodiversity hotspots was first introduced with 25 regions meeting the criteria. Later, the list was expanded to 34 hotspots, covering critical areas for conservation.
Q30. Assertion: Ex situ conservation is desirable for endangered organisms facing high risk of extinction.
Reason: They are protected in their natural habitat in this approach.
Correct Answer: (a)
The assertion is true: ex situ conservation (off‑site) is used for species that cannot survive in the wild. But the reason is false because ex situ involves protecting species outside their natural habitats, e.g., in zoos, botanical gardens, or seed banks.
Q31. Which of the following correctly describes 'Genetic Diversity'? (i) Diversity within a single species. (ii) Shown by Rauwolfia vomitoria in terms of reserpine potency. (iii) Rice has 50,000 genetically different strains in India.
Correct Answer: (a)
Genetic diversity refers to variation within a species; examples include the reserpine content in Rauwolfia and the numerous rice strains in India. All statements are correct.
Q32. Match the types of biodiversity in Column-I with examples in Column-II:
Column-I
Column-II
A. Genetic diversity
(I) Amphibians in Western Ghats
B. Species diversity
(II) Deserts and Rain forests in India
C. Ecological diversity
(III) 50,000 strains of rice
Correct Answer: (a)
Genetic diversity is illustrated by many rice strains; species diversity is exemplified by the variety of amphibians in the Western Ghats; ecological diversity is shown by India's diverse ecosystems like deserts and rainforests. Thus A–III, B–I, C–II.
Q33. Assertion: Biodiversity increases with increasing explored area, but only up to a limit.
Reason: Alexander von Humboldt noted this in South American jungles.
Correct Answer: (b)
Both statements are correct: Humboldt did observe that species richness increases with area, and he also noted that the relationship reaches a plateau. However, the reason simply states an observation made by Humboldt; it does not explain the limit itself, which is due to factors like habitat heterogeneity and sampling saturation.
Q34. Assertion: Small standing crop of phytoplankton can support large standing crop of zooplankton in the sea.
Reason: This results in an inverted pyramid of biomass.
Correct Answer: (b)
Both the assertion and reason are correct: phytoplankton have a small standing crop but support a larger zooplankton biomass in many aquatic ecosystems, producing an inverted biomass pyramid. However, the reason (the existence of the inverted pyramid) is a result, not an explanation for the phenomenon; the cause lies in the high turnover rate and rapid reproduction of phytoplankton.
Q35. Which of the following is an example of ex situ conservation?
Correct Answer: (c)
Zoological parks (zoos) are classic examples of ex situ conservation, where endangered species are bred and maintained outside their natural habitats. This approach complements in situ conservation by providing a safe environment for species facing extinction in the wild.
Q36. The IUCN Red List (2004) documents the extinction of how many species in the last 500 years?
Correct Answer: (b)
The IUCN Red List (2004) reported that 784 species have become extinct in the past 500 years. This includes well‑known cases like the dodo and quagga, though many more species are currently threatened with extinction.
Q37. Among animals, which taxonomic group is the most species-rich?
Correct Answer: (c)
Insects are the most species-rich taxonomic group among animals, with over a million described species. They constitute more than 70% of all known animal species, reflecting their evolutionary success in diverse habitats.
Q38. Identify true statements for 'Mass Extinction': (i) Five episodes have happened since life's origin. (ii) The 'Sixth Extinction' is currently in progress.
Correct Answer: (a)
There have been five major mass extinction events in Earth's history, and many scientists believe we are now in the sixth, driven by human activities. Both statements are correct.
Q39. Which of the following is correct regarding 'Ecological Diversity'? (i) Norway has a greater ecosystem diversity than India. (ii) India has greater diversity than Norway due to its deserts, mangroves and coral reefs.
Correct Answer: (a)
India has greater ecological diversity than Norway because it encompasses a wide range of ecosystems (deserts, mangroves, rainforests, coral reefs), whereas Norway has limited habitat types. Thus only (ii) is correct.
Q40. For frugivorous birds and mammals in tropical forests of different continents, the Z value is:
Correct Answer: (c)
When comparing species richness across entire continents for groups like frugivorous birds and mammals, the Z value is higher (about 1.15). This steeper slope indicates that intercontinental comparisons yield a more rapid increase in richness with area.
Q41. India has more than ______ genetically different strains of rice.
Correct Answer: (c)
India is a centre of origin for rice and possesses enormous genetic diversity within this crop. More than 50,000 genetically distinct strains of rice have been recorded, making it a rich reservoir of genetic resources for breeding and food security.
Q42. Which of the following is correct? (i) Diversity exists at all levels of biological organisation. (ii) Biodiversity is a vital environmental issue of international concern. (iii) We could lose all wealth in less than two centuries at current loss rates.
Correct Answer: (a)
Biodiversity spans genes, species, and ecosystems; it is a global concern; and at current rates, a significant portion of biodiversity could be lost within two centuries. All statements are correct.
Q43. Which of the following statements about 'Amazonian rain forest' is/are correct? (i) It is called the 'lungs of the planet'. (ii) It contains more than 40,000 species of plants. (iii) It is located in South America.
Correct Answer: (a)
All statements are true: the Amazon is indeed called the lungs of the planet, hosts over 40,000 plant species, and is situated in South America, spanning several countries.
Q44. Identify correct facts about 'Extinctions': (i) 15,500 species are currently facing threat of extinction. (ii) Three subspecies of tiger (Bali, Javan, Caspian) are extinct. (iii) 12% of bird species are threatened.
Correct Answer: (a)
About 15,500 species are threatened; three tiger subspecies are extinct; and 12% of bird species are threatened. These are well‑documented facts, so all statements are correct.
Q45. Which is true for 'Species-Area' regression slope Z? (i) For regions like Britain, Z is 0.1 to 0.2. (ii) For entire continents, Z is 0.6 to 1.2. (iii) Steeper slope means richness increases faster with area.
Correct Answer: (a)
Z values are indeed 0.1–0.2 for small regions and 0.6–1.2 for larger areas. A steeper slope indicates a faster increase in species richness with increasing area, so all statements are correct.
Q46. Which of the following is a recently extinct species from Mauritius?
Correct Answer: (c)
The dodo was a flightless bird endemic to Mauritius that became extinct in the late 17th century due to hunting and habitat destruction. It is one of the most iconic examples of human‑caused extinction.
Q47. Who gave the 'Rivet Popper Hypothesis' to explain the importance of biodiversity?
Correct Answer: (b)
The 'Rivet Popper Hypothesis' was proposed by Stanford ecologist Paul Ehrlich. It uses an airplane analogy to illustrate that each species (rivet) plays a role in ecosystem function, and losing species gradually weakens the ecosystem's integrity.
Q48. Which sociobiologist popularised the term 'biodiversity'?
Correct Answer: (b)
The term 'biodiversity' was brought into common usage by the sociobiologist Edward O. Wilson. Although earlier naturalists like Humboldt described species richness, it was Wilson who popularised the concept in the context of conservation biology and public awareness.
Q49. The Nile perch introduced into Lake Victoria led to the extinction of over 200 species of:
Correct Answer: (b)
The introduction of the Nile perch into Lake Victoria caused a catastrophic decline in native cichlid fish diversity. More than 200 endemic cichlid species were driven to extinction by this invasive predator, altering the lake's ecosystem.
Q50. Sacred groves in Meghalaya are found in:
Correct Answer: (c)
In Meghalaya, sacred groves are located in the Khasi and Jaintia Hills. These forest patches are protected by local communities for religious and cultural reasons, serving as refuge for many endemic and threatened species.
Q51. Regarding 'World Summit (2002)': (i) Held in Johannesburg, South Africa. (ii) 190 countries pledged commitment. (iii) Goal was significant reduction in biodiversity loss rate by 2010.
Correct Answer: (a)
The 2002 World Summit was in Johannesburg; 190 countries made commitments; and they set the 2010 target to reduce biodiversity loss. All statements are accurate.
Q52. More than ______ per cent of all the species recorded are animals.
Correct Answer: (c)
Animals dominate the known species inventory, accounting for more than 70% of all recorded species. This is largely due to the enormous number of insect species, which far outnumber all other animal groups combined.
Q53. The World Summit on Sustainable Development (2002) was held in:
Correct Answer: (c)
The World Summit on Sustainable Development took place in Johannesburg, South Africa, in 2002. It reaffirmed global commitment to sustainable development and set targets to significantly reduce the rate of biodiversity loss by 2010.
Q54. India's share of the global species diversity is an impressive:
Correct Answer: (c)
Despite having only 2.4% of the world's land area, India contributes about 8.1% of the global species diversity. This makes India one of the 12 mega‑diverse countries, with high levels of endemism and species richness.
Q55. What happens to the species-area relationship on a logarithmic scale?
Correct Answer: (b)
On a logarithmic scale, the species‑area relationship becomes a straight line, as described by the equation log S = log C + Z log A. This linearisation simplifies analysis and allows easy estimation of parameters such as the slope Z.
Q56. Correct statements for 'Amazon Rain Forest' loss include: (i) It is being cut for cultivating soya beans. (ii) It is being converted to grasslands for beef cattle. (iii) Once covered 14% of land, now only 6%.
Correct Answer: (a)
Amazon deforestation is driven by agriculture (soya beans) and cattle ranching. It has been reduced from 14% to 6% of Earth's land surface. All statements are correct.
Q57. Regarding 'Loss of Biodiversity', which statements are correct? (i) Amphibians appear to be more vulnerable to extinction. (ii) Current extinction rates are 100-1000 times faster than pre-human times. (iii) Loss of biodiversity leads to decline in plant production.
Correct Answer: (a)
All statements are correct: amphibians have high extinction vulnerability, current extinction rates are dramatically accelerated, and biodiversity loss reduces ecosystem productivity and services.
Q58. Assertion: Protoplasmic streaming is a simple form of movement.
Reason: It is seen in unicellular organisms like Amoeba.
Correct Answer: (a)
Protoplasmic streaming is indeed a simple movement mechanism observed in unicellular organisms such as Amoeba. The reason correctly identifies an example and explains that it is a characteristic of simple organisms, thus supporting the assertion.
Q59. Assertion: When a host fish becomes extinct, its unique parasites also meet the same fate.
Reason: This phenomenon is known as alien species invasion.
Correct Answer: (a)
The assertion is true: when a host species goes extinct, its dependent parasites also vanish (co‑extinction). However, the reason is false because this phenomenon is called co‑extinction, not alien species invasion. Alien invasion involves introduced species, not the loss of dependent organisms.
Q60. The number of biodiversity hotspots identified in the world is:
Correct Answer: (b)
Currently, 34 biodiversity hotspots have been identified worldwide. These are regions with exceptionally high species richness and endemism, but that have lost at least 70% of their original natural vegetation, making them conservation priorities.
Q61. In the equation log S = log C + Z log A, 'Z' represents the:
Correct Answer: (c)
In the species‑area equation, Z is the slope of the log‑log plot, i.e., the regression coefficient. It indicates how rapidly species richness increases with area; its value depends on the taxonomic group and geographic scale.
Q62. Identify true statements for 'In situ' in India: (i) 14 Biosphere Reserves. (ii) 90 National Parks. (iii) 448 Wildlife Sanctuaries.
Correct Answer: (a)
India has 14 Biosphere Reserves, 90 National Parks, and 448 Wildlife Sanctuaries (as per the referenced data). These are all in situ conservation areas, so all statements are correct.
Q63. The species-area relationship generally turns out to be a:
Correct Answer: (c)
When plotted on linear scales, the species‑area relationship often follows a rectangular hyperbola. This means that as the area increases, species richness increases rapidly at first and then slows down, reflecting the species‑area curve.
Q64. Match the alien species in Column-I with the locations/impacts in Column-II:
Column-I
Column-II
A. Nile perch
(I) Australian rangeland
B. Prickly pear cactus
(II) Lake Victoria
C. Clarias gariepinus
(III) Threat to indigenous catfishes
Correct Answer: (a)
Nile perch was introduced to Lake Victoria; prickly pear cactus became invasive in Australian rangelands; African catfish threatens native catfish in India. Correct matching: A–II, B–I, C–III.
Q65. Assertion: Bioprospecting can lead to enormous economic benefits.
Reason: It involves exploring molecular and species-level diversity for products of economic importance.
Correct Answer: (a)
Both the assertion and reason are correct. Bioprospecting directly aims to discover commercially valuable compounds, and its economic potential is derived from the diversity it explores. The reason explains why bioprospecting can be highly profitable.
Q66. Robert May places the global species diversity at about:
Correct Answer: (b)
Robert May, a prominent ecologist, estimated the global species diversity to be around 7 million. This is a conservative estimate based on extrapolations from known groups, especially insects and microorganisms, and is widely accepted in biodiversity studies.
Q67. Amazon forest is estimated to produce, through photosynthesis, ______ per cent of the total oxygen in the earth’s atmosphere.
Correct Answer: (b)
The Amazon rain forest is often called the 'lungs of the planet' because it contributes about 20% of the Earth's atmospheric oxygen through photosynthesis. However, much of this oxygen is consumed by respiration within the forest itself.
Q68. Match the following for 'The Evil Quartet':
Cause
Example/Impact
A. Habitat loss
(I) Amazon rain forest
B. Over-exploitation
(II) Passenger pigeon
C. Alien invasion
(III) Water hyacinth
D. Co-extinction
(IV) Plant-pollinator mutualism
Correct Answer: (a)
Amazon deforestation exemplifies habitat loss; passenger pigeon is a classic over‑exploitation case; water hyacinth is an invasive alien species; and loss of a plant may cause co‑extinction of its pollinator. So A–I, B–II, C–III, D–IV.
Q70. Assertion: Alien species can turn invasive and cause extinction of indigenous species.
Reason: They lack natural predators in the new geographical area.
Correct Answer: (a)
Both statements are true. Alien species become invasive partly because they escape their natural predators, parasites, and competitors, allowing their populations to explode and outcompete native species. This lack of natural checks explains their detrimental impact.
Q71. How many plant species contribute to traditional medicines used by native peoples?
Correct Answer: (b)
Approximately 25,000 plant species are used in traditional medicine by indigenous communities around the world. This vast number highlights the direct dependence of human health on plant biodiversity, especially in developing countries.
Q72. Identify the correct statements for 'Ex situ' conservation: (i) Zoological parks and Botanical gardens serve this purpose. (ii) Cryopreservation can store gametes in fertile condition. (iii) Plants can be propagated using tissue culture.
Correct Answer: (a)
Ex situ conservation encompasses zoos, botanical gardens, cryopreservation, seed banks, and tissue culture. All three listed methods are valid ex situ approaches.
Q73. The greatest biodiversity on earth is found in the:
Correct Answer: (b)
The Amazonian rain forest is the most biodiverse region on Earth, harboring an estimated one‑third of all terrestrial species. Its vast area, stable climate, and complex structure support an unparalleled diversity of plants, animals, and microorganisms.
Q74. Which statements about 'Species-Area Relationship' are true? (i) Developed by Alexander von Humboldt. (ii) Graph is a rectangular hyperbola on normal scale. (iii) Value of Z is independent of the taxonomic group for small areas.
Correct Answer: (a)
Humboldt first described the relationship; on a linear scale it forms a rectangular hyperbola; and for small areas, Z typically lies between 0.1 and 0.2 across taxa. Thus all statements are true.
Q75. Species confined to a specific region and not found anywhere else are called:
Correct Answer: (b)
Endemic species are those that are restricted to a particular geographic area and are not naturally found elsewhere. Endemism is a key criterion for identifying biodiversity hotspots, as these species are highly vulnerable to local extinction.
Q76. Which invasive weed species is commonly called 'Water Hyacinth'?
Correct Answer: (c)
Water hyacinth is the common name for the aquatic plant Eichhornia crassipes (spelled as Eicchornia in the question). It is a notorious invasive weed that clogs waterways and depletes oxygen, causing severe ecological and economic damage.
Q77. Match the following for global biodiversity percentages:
A. Invertebrates - Insects
70 % of animals
B. Plants total
22 %
C. Vertebrates - Fishes
Nearly half of total vertebrates (implied by chart)
Correct Answer: (a)
All three statements are factually correct: insects make up 70% of animal species; plants comprise about 22% of all species; and fishes account for nearly half of all vertebrate species (based on known biodiversity proportions).
Q78. Match the species with their extinction locations or reasons:
Column-I (Species)
Column-II (Detail)
A. Dodo
(I) Africa
B. Quagga
(II) Mauritius
C. Thylacine
(III) Russia
D. Steller’s Sea Cow
(IV) Australia
Correct Answer: (a)
The Dodo was endemic to Mauritius; the Quagga lived in Africa (South Africa); the Thylacine (Tasmanian tiger) was from Australia; and Steller's sea cow was found in the Bering Sea (Russia). Correct matching: A–II, B–I, C–IV, D–III.
Q79. Select correct statements for 'Alien Species' in India: (i) Parthenium (carrot grass) is an invasive weed. (ii) Lantana and Eicchornia are invasive weeds. (iii) African catfish is a threat to indigenous catfish.
Correct Answer: (a)
Parthenium, Lantana, and water hyacinth (Eichhornia) are invasive weeds in India; the African catfish is an alien species threatening native fish. So all statements are correct.
Q80. In India, the number of Biosphere Reserves is:
Correct Answer: (c)
India has established 14 Biosphere Reserves as part of the UNESCO Man and Biosphere Programme. These reserves aim to conserve biodiversity while promoting sustainable development, and include famous sites like Nilgiri, Sundarbans, and Nanda Devi.
Q81. Identify the correct statements regarding the 'Rivet Popper Hypothesis': (i) An airplane is an analogy for the ecosystem. (ii) Rivets represent the species. (iii) Taking a rivet home represents extinction.
Correct Answer: (a)
In Ehrlich's analogy, the airplane represents the ecosystem, each species is a rivet, and removing a rivet (extinction) weakens the structure. All three statements are correct.
Q82. According to the IUCN (2004), the total number of plant and animal species described so far is slightly more than:
Correct Answer: (a)
By 2004, the IUCN had catalogued just over 1.5 million species of plants and animals. This figure represents the known and described species, though the actual number on Earth is estimated to be much higher, possibly several million.
Q83. Assertion: Habitat loss is the most important cause driving animals to extinction.
Reason: Tropical rain forests have been reduced from 14% to 6% of earth's land surface.
Correct Answer: (a)
Both statements are true, and the reason provides a concrete example of how habitat loss occurs. The dramatic reduction of tropical rain forests exemplifies the destruction of the most biodiverse ecosystems, which is the primary driver of species extinctions.
Q84. Identify the correct statements regarding India's biodiversity: (i) India has only 2.4 per cent of the world's land area. (ii) India is one of the 12 mega diversity countries of the world. (iii) Nearly 1,00,000 plant species are yet to be discovered in India.
Correct Answer: (a)
All three statements are correct: India occupies 2.4% of the global land area, is a mega‑diverse country, and still has many undiscovered species (estimated to be around 100,000 for plants and animals combined).
Q85. Assertion: Pollution is a threat to the survival of many species.
Reason: It leads to habitat degradation.
Correct Answer: (a)
Pollution directly degrades habitats by contaminating air, water, and soil, which in turn harms organisms. The assertion that pollution threatens species is true, and the reason correctly explains the mechanism – habitat degradation – through which pollution exerts its impact.
Q86. Which of the following are causes of 'The Evil Quartet'? (i) Habitat loss and fragmentation. (ii) Over-exploitation. (iii) Alien species invasion.
Correct Answer: (a)
The Evil Quartet consists of habitat loss, over‑exploitation, alien species invasions, and co‑extinctions. All three options (i, ii, iii) are part of this quartet, so all are correct.
Q87. Assertion: Communities with more species tend to be more stable.
Reason: David Tilman found that plots with more species showed less year-to-year variation in total biomass.
Correct Answer: (a)
Both the assertion and reason are true. Tilman's long‑term experiments demonstrated that higher species diversity reduces temporal variation in biomass, providing direct evidence that more diverse communities are more stable and resilient to disturbances.
Q88. The Western Ghats have a greater ______ species diversity than the Eastern Ghats.
Correct Answer: (b)
The Western Ghats are a biodiversity hotspot with high endemism and species richness, particularly for amphibians. They harbour more amphibian species than the Eastern Ghats due to favourable climatic conditions and habitat complexity.
Q89. The 'Earth Summit' (1992) was held in:
Correct Answer: (b)
The Earth Summit, officially the United Nations Conference on Environment and Development (UNCED), was held in Rio de Janeiro, Brazil, in 1992. It resulted in the Convention on Biological Diversity, which was signed by many nations.
Q90. Assertion: Steller's sea cow became extinct in the last 500 years.
Reason: It was over-exploited by humans.
Correct Answer: (a)
Steller's sea cow was a marine mammal that was driven to extinction within 27 years of its discovery, primarily due to over‑hunting for its meat and blubber. The reason correctly identifies over‑exploitation as the cause, explaining the extinction event.
Q91. Which are correct regarding 'Lantana' and 'Eicchornia'? (i) They are invasive weed species. (ii) They cause environmental damage. (iii) They were introduced deliberately.
Correct Answer: (a)
Lantana and water hyacinth are both invasive weeds, cause significant environmental harm, and were introduced intentionally for ornamental or other purposes. All statements are correct.
Q92. Plants (including fungi) comprise no more than ______ per cent of the total global biodiversity.
Correct Answer: (b)
Plants and fungi together make up about 22% of the total known biodiversity. While plants are vital for ecosystem function, their species count is far less than that of animals, especially insects, which dominate the overall numbers.
Q93. Match the taxonomic categories in Column-I with their proportions in global biodiversity in Column-II:
Column-I
Column-II
A. Animals
(I) 22 %
B. Plants
(II) 70 % of animals
C. Insects
(III) 8.1 %
D. India's share
(IV) > 70 %
Correct Answer: (a)
Animals account for >70% of all known species; plants (including fungi) make up ~22%; insects alone constitute about 70% of all animals; and India's share is 8.1% of the global total. The correct matching is A–IV, B–I, C–II, D–III.
Q94. Match the conservation strategy with the example:
Column-I
Column-II
A. In situ
(I) Seed banks
B. Ex situ
(II) Wildlife Sanctuaries
C. Hotspot
(III) Western Ghats
Correct Answer: (a)
In situ conservation occurs in natural habitats (wildlife sanctuaries); ex situ involves off‑site methods (seed banks); hotspots are regions like the Western Ghats. Therefore A–II, B–I, C–III.
Q95. Identify the correct statements for 'Conservation' justifications: (i) Direct economic benefits are narrowly utilitarian. (ii) Ecosystem services are broadly utilitarian. (iii) Intrinsic value of species is an ethical argument.
Correct Answer: (a)
The three major arguments are correctly categorised: narrow utilitarian = direct economic gains; broad utilitarian = ecosystem services; ethical = intrinsic value. All statements are correct.
Q96. Assertion: Fungi have more species than the combined total of all vertebrate species.
Reason: Vertebrates include fishes, amphibians, reptiles and mammals.
Correct Answer: (b)
Both statements are true: fungi are indeed more species‑rich than all vertebrates combined. However, listing the vertebrate groups does not explain why fungi are more numerous; the high diversity of fungi is due to their evolutionary history and ecological roles, not because vertebrates are fewer.
Q97. Which of the following phylum/group is being described by the given statements? (i) These comprise more than 70 per cent of all animals recorded. (ii) That means, out of every 10 animals, 7 are of this group. (iii) They represent the most species-rich taxonomic group.
Correct Answer: (b)
The described group is insects (Arthropoda). They make up more than 70% of all animal species, and are the most species‑rich taxon, with over a million described species.
Q98. Assertion: The 'Sixth Extinction' is different from previous episodes.
Reason: The current species extinction rates are 100 to 1,000 times faster than in pre-human times.
Correct Answer: (a)
The assertion is correct: the ongoing sixth extinction is distinct because it is driven by human activities. The reason accurately explains this difference, as current extinction rates are indeed orders of magnitude higher than background rates, making this crisis unique.
Q99. Assertion: Biodiversity hotspots together cover less than 2 per cent of the earth’s land area.
Reason: India has three biodiversity hotspots: Western Ghats-Sri Lanka, Indo-Burma and Himalaya.
Correct Answer: (b)
Both statements are factual: hotspots do cover less than 2% of land, and India hosts three hotspots. However, the reason does not explain the global area percentage; it merely states an additional fact about India. Hence the reason is not a correct explanation for the assertion.
Q100. Match the following for Sacred Groves:
Location
Groves
A. Meghalaya
(I) Khasi and Jaintia Hills
B. Rajasthan
(II) Aravalli Hills
C. MP
(III) Bastar areas
Correct Answer: (a)
In Meghalaya, sacred groves are in Khasi and Jaintia Hills; in Rajasthan they are in the Aravalli Hills; in Madhya Pradesh they occur in the Bastar region. Thus A–I, B–II, C–III.