MCQs on Biodiversity and Conservation – Class 12 Biology NCERT
MCQs on Biodiversity and Conservation – Class 12 Biology (NCERT Based)
Course: CBSE Class 12 Biology
Unit V: Ecology and Environment
Topic: Biodiversity and Conservation
These 50 Multiple Choice Questions (MCQs) are strictly aligned with the NCERT syllabus and are structured section-wise for clear conceptual understanding. Each question is followed by the correct answer and a detailed explanation, making them ideal for CBSE Class 12 Board Exams and competitive exam revision.
Section A: Biodiversity – Meaning and Levels (Q1–Q10)
Q1. Biodiversity refers to:
A. Variety of plants only
B. Variety of animals only
C. Variety of living organisms at all levels
D. Variety of ecosystems only
Answer: C
Explanation: Biodiversity includes diversity at genetic, species, and ecosystem levels, covering all living organisms.
Q2. Which of the following represents genetic diversity?
A. Different species in a forest
B. Different ecosystems in India
C. Variations within a species
D. Different biomes on Earth
Answer: C
Explanation: Genetic diversity refers to variations within the same species, such as different varieties of rice.
Q3. Species richness is defined as:
A. Number of individuals in a species
B. Number of species in a given area
C. Number of ecosystems in a region
D. Genetic variation within species
Answer: B
Explanation: Species richness indicates how many species are present in a particular area.
Q4. Which level of biodiversity includes forests, grasslands, and deserts?
A. Genetic diversity
B. Species diversity
C. Ecosystem diversity
D. Population diversity
Answer: C
Explanation: Ecosystem diversity refers to variety of habitats, communities, and ecological processes.
Q5. India is considered a megadiversity nation because:
A. It has a large population
B. It has diverse climates and ecosystems
C. It has the largest forest cover
D. It has only endemic species
Answer: B
Explanation: India shows high species richness and ecosystem diversity due to varied climatic zones.
Q6. Which of the following contributes most to species diversity?
A. Latitude
B. Longitude
C. Altitude
D. Soil type
Answer: A
Explanation: Species diversity increases from poles to equator, known as the latitudinal gradient.
Q7. The diversity observed within a community is called:
A. Alpha diversity
B. Beta diversity
C. Gamma diversity
D. Delta diversity
Answer: A
Explanation: Alpha diversity refers to species diversity within a particular area or ecosystem.
Q8. Which region has the highest biodiversity?
A. Tundra
B. Tropical rainforest
C. Desert
D. Temperate forest
Answer: B
Explanation: Tropical rainforests have stable climate and high productivity, supporting maximum biodiversity.
Q9. Biodiversity hotspots are areas with:
A. High rainfall
B. High endemic species and high threat
C. High population density
D. Large forest cover
Answer: B
Explanation: Hotspots have many endemic species and face severe habitat loss.
Q10. Which of the following is NOT a level of biodiversity?
A. Genetic
B. Species
C. Ecosystem
D. Community
Answer: D
Explanation: NCERT recognizes genetic, species, and ecosystem diversity as main levels.
Section B: Patterns and Importance of Biodiversity (Q11–Q20)
Q11. The latitudinal gradient in biodiversity indicates:
A. Increase in biodiversity from equator to poles
B. Decrease in biodiversity from equator to poles
C. Uniform biodiversity across latitudes
D. Biodiversity depends only on altitude
Answer: B
Explanation: Biodiversity is maximum at the equator and decreases towards poles.
Q12. Which hypothesis explains high tropical biodiversity due to long evolutionary time?
A. Climatic stability hypothesis
B. Species–area relationship
C. Evolutionary time hypothesis
D. Productivity hypothesis
Answer: C
Explanation: Tropics remained undisturbed for millions of years, allowing more species to evolve.
Q13. The species–area relationship was proposed by:
A. Darwin
B. Humboldt
C. Wallace
D. Mendel
Answer: B
Explanation: Alexander von Humboldt described the relationship between species richness and area.
Q14. The mathematical expression for species–area relationship is:
A. S = CAᶻ
B. S = AᶻC
C. S = ZCA
D. S = A/C
Answer: A
Explanation: Species richness (S) increases with area (A) following S = CAᶻ.
Q15. Biodiversity contributes to ecosystem stability by:
A. Reducing productivity
B. Increasing species extinction
C. Enhancing resistance to disturbances
D. Decreasing nutrient cycling
Answer: C
Explanation: Diverse ecosystems are more stable and resilient to environmental changes.
Q16. Which ecosystem service is provided by biodiversity?
A. Oxygen production
B. Pollination
C. Nutrient cycling
D. All of the above
Answer: D
Explanation: Biodiversity supports essential ecosystem services crucial for life.
Q17. Loss of biodiversity can lead to:
A. Ecosystem stability
B. Increased productivity
C. Ecosystem collapse
D. Climate regulation
Answer: C
Explanation: Biodiversity loss destabilizes ecosystems and disrupts ecological balance.
Q18. Which of the following is an aesthetic value of biodiversity?
A. Timber
B. Medicine
C. Ecotourism
D. Fuel
Answer: C
Explanation: Aesthetic values include recreation, tourism, and cultural significance.
Q19. Which biodiversity value is associated with future potential use?
A. Ethical value
B. Aesthetic value
C. Option value
D. Economic value
Answer: C
Explanation: Option value refers to potential future benefits of species not yet known.
Q20. Ethical value of biodiversity implies:
A. Economic use
B. Moral duty to protect life
C. Scientific research
D. Industrial application
Answer: B
Explanation: Ethical value stresses moral responsibility to conserve all life forms.
Section C: Biodiversity Loss and Threats (Q21–Q35)
Q21. Which is the most important cause of biodiversity loss?
A. Overgrazing
B. Habitat loss and fragmentation
C. Pollution
D. Climate change
Answer: B
Explanation: Habitat destruction is the primary cause of species extinction.
Q22. The term “Evil Quartet” includes all except:
A. Habitat loss
B. Overexploitation
C. Alien species invasion
D. Afforestation
Answer: D
Explanation: The Evil Quartet includes habitat loss, overexploitation, invasive species, and co-extinction.
Q23. Which invasive species caused decline of native species?
A. Lantana
B. Water hyacinth
C. Parthenium
D. All of the above
Answer: D
Explanation: These invasive species outcompete native flora.
Q24. Co-extinction refers to:
A. Simultaneous extinction of species
B. Extinction of predators only
C. Extinction of prey only
D. Extinction due to pollution
Answer: A
Explanation: When one species becomes extinct, associated species also disappear.
Q25. Which human activity leads to overexploitation?
A. Sustainable use
B. Hunting and poaching
C. Afforestation
D. Conservation
Answer: B
Explanation: Excessive hunting and harvesting reduce population size.
Q26. IUCN Red List provides information on:
A. Endangered plants only
B. Threatened animal species
C. Conservation status of species
D. Forest cover
Answer: C
Explanation: IUCN Red List categorizes species based on risk of extinction.
Q27. Which category represents species facing highest extinction risk?
A. Vulnerable
B. Endangered
C. Critically endangered
D. Rare
Answer: C
Explanation: Critically endangered species are on the verge of extinction.
Q28. Extinction rate today is estimated to be:
A. Natural rate
B. Lower than background rate
C. Same as fossil records
D. 100–1000 times higher than natural rate
Answer: D
Explanation: Human activities have accelerated extinction rates dramatically.
Q29. Which biome is most affected by deforestation?
A. Tundra
B. Tropical rainforest
C. Desert
D. Grassland
Answer: B
Explanation: Tropical rainforests face maximum habitat destruction.
Q30. Climate change affects biodiversity by:
A. Shifting species distribution
B. Causing coral bleaching
C. Altering breeding patterns
D. All of the above
Answer: D
Explanation: Climate change impacts survival, reproduction, and distribution of species.
Q31. Overfishing leads to:
A. Sustainable fisheries
B. Increased biodiversity
C. Collapse of fish populations
D. Ecosystem stability
Answer: C
Explanation: Overfishing reduces fish stocks beyond recovery.
Q32. Which practice causes habitat fragmentation?
A. Large dams and roads
B. Organic farming
C. Wildlife corridors
D. Conservation reserves
Answer: A
Explanation: Infrastructure divides habitats into isolated fragments.
Q33. Alien species become invasive because:
A. Lack of predators
B. High reproductive rate
C. Competitive advantage
D. All of the above
Answer: D
Explanation: Invasive species thrive due to absence of natural control.
Q34. Which species is extinct in the wild but survives in captivity?
A. Endangered
B. Vulnerable
C. Extinct
D. Extinct in the wild
Answer: D
Explanation: Such species exist only in zoos or botanical gardens.
Q35. Poaching primarily threatens:
A. Plants
B. Microorganisms
C. Large mammals
D. Insects
Answer: C
Explanation: Large mammals are targeted for meat, skin, tusks, or horns.
Section D: Biodiversity Conservation Strategies (Q36–Q50)
Q36. Conservation within natural habitat is called:
A. Ex situ conservation
B. In situ conservation
C. Artificial conservation
D. Gene conservation
Answer: B
Explanation: In situ conservation protects species in their natural environment.
Q37. National parks and wildlife sanctuaries are examples of:
A. Ex situ conservation
B. Gene banks
C. In situ conservation
D. Cryopreservation
Answer: C
Explanation: These areas conserve entire ecosystems.
Q38. Botanical gardens are examples of:
A. In situ conservation
B. Ex situ conservation
C. Biosphere reserves
D. Sacred groves
Answer: B
Explanation: Ex situ conservation involves protection outside natural habitats.
Q39. Which conservation method preserves genetic material at low temperatures?
A. Seed banks
B. Cryopreservation
C. Tissue culture
D. Cloning
Answer: B
Explanation: Cryopreservation stores gametes, seeds, or embryos at very low temperatures.
Q40. Sacred groves help in conservation by:
A. Legal protection
B. Religious beliefs
C. Government policies
D. Scientific management
Answer: B
Explanation: Traditional beliefs prevent exploitation, aiding conservation.
Q41. Biosphere reserves differ from national parks because they:
A. Allow human activities in buffer zones
B. Are smaller in size
C. Protect only animals
D. Are man-made
Answer: A
Explanation: Biosphere reserves integrate conservation with sustainable use.
Q42. The main objective of biodiversity conservation is to:
A. Increase population
B. Prevent extinction
C. Maintain ecological balance
D. All of the above
Answer: D
Explanation: Conservation aims at sustainability, stability, and survival of life.
Q43. Wildlife Protection Act in India was enacted in:
A. 1950
B. 1972
C. 1986
D. 2000
Answer: B
Explanation: The Act provides legal protection to wildlife species.
Q44. Which is an example of ex situ conservation?
A. National park
B. Wildlife sanctuary
C. Zoological park
D. Biosphere reserve
Answer: C
Explanation: Zoos conserve animals outside their natural habitats.
Q45. Seed banks are important because they:
A. Preserve biodiversity
B. Store genetic material
C. Help in future restoration
D. All of the above
Answer: D
Explanation: Seed banks ensure long-term conservation of plant diversity.
Q46. Which international organization focuses on biodiversity conservation?
A. WHO
B. UNESCO
C. IUCN
D. FAO
Answer: C
Explanation: IUCN assesses conservation status and promotes protection efforts.
Q47. Sustainable development means:
A. Using resources without concern
B. Development without conservation
C. Development that meets present needs without harming future needs
D. Industrial growth only
Answer: C
Explanation: Sustainable development balances economic growth and environmental protection.
Q48. Community participation is important because:
A. Locals depend on biodiversity
B. Conservation becomes effective
C. Traditional knowledge is utilized
D. All of the above
Answer: D
Explanation: Involving communities ensures long-term success of conservation programs.
Q49. The main aim of Project Tiger is to:
A. Increase forest cover
B. Protect biodiversity hotspots
C. Conserve tiger population
D. Promote ecotourism
Answer: C
Explanation: Project Tiger focuses on protecting tigers and their habitats.
Q50. Conservation of biodiversity is essential because:
A. It supports life-support systems
B. It ensures ecological stability
C. It provides resources for humans
D. All of the above
Answer: D
Explanation: Biodiversity conservation is crucial for survival, sustainability, and well-being of life on Earth.
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