Below are 16 practice questions on Biodiversity and Conservation, sorted Easy → Hard. Tap “Show answer & explanation” under any question to check yourself. Want the full theory first? Read the Biodiversity and Conservation notes.
🔬 Biology · Class 12 · NEET
Biodiversity and Conservation — Practice Questions with Answers
16 free MCQs on Biodiversity and Conservation with worked answers and explanations. Levels of biodiversity, species richness patterns, threats (HIPPO), and conservation strategies. Always in NEET.
Take the timed Biodiversity and Conservation quiz →Easy — 7 questions
Q1.
An ecosystem consists of:
- A Mainly the living organisms present in an area
- B Mainly the non-living physical factors present
- C Living organisms and their non-living environment
- D Mainly the plant and animal species in a region
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Answer: C. Living organisms and their non-living environment
Why: An ecosystem includes all living organisms (biotic) AND their physical environment (abiotic factors like water, temperature, soil).
Q2.
An extinct species is one that:
- A Is currently classified as an endangered species
- B No longer exists anywhere on Earth
- C Exists today mainly in zoos and captive breeding programs
- D Has a population that has been steadily reduced over time
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Answer: B. No longer exists anywhere on Earth
Why: Extinction: a species no longer exists anywhere on Earth. The last individual has died. Cannot be recovered.
Q3.
Greenhouse gases include:
- A Oxygen (O2) and nitrogen (N2)
- B CO2, CH4, N2O, and water vapor
- C Carbon dioxide (CO2) mainly
- D Oxygen (O2) gas mainly
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Answer: B. CO2, CH4, N2O, and water vapor
Why: Greenhouse gases (CO2, methane, N2O, H2O vapor) trap heat in the atmosphere, causing the greenhouse effect.
Q4.
An endangered species is one that:
- A Has already gone largely extinct worldwide
- B Is at high risk of extinction in the near future
- C Has largely recovered its former population size
- D Is native to mainly one single country
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Answer: B. Is at high risk of extinction in the near future
Why: An endangered species is at very high risk of extinction. Conservation efforts aim to prevent their extinction.
Q5.
The water cycle involves:
- A Mainly the rainfall that reaches the ground surface directly
- B Evaporation, condensation, precipitation, and transpiration
- C Mainly the underground movement and storage of groundwater
- D Mainly the circulation pattern driving major ocean currents
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Answer: B. Evaporation, condensation, precipitation, and transpiration
Why: Water cycle: evaporation (water → vapor), condensation (vapor → clouds), precipitation (rain/snow), infiltration, and transpiration.
Q6.
National parks conserve biodiversity. This is an example of:
- A Ex-situ conservation outside its habitat
- B In-situ conservation (in natural habitat)
- C Gene bank storage of seed material
- D Captive zoo-based breeding program
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Answer: B. In-situ conservation (in natural habitat)
Why: In-situ conservation preserves species in their natural habitats (national parks, wildlife sanctuaries, biosphere reserves).
Q7.
Acid rain is caused by:
- A A gradual buildup of excess atmospheric carbon dioxide alone
- B SO2 and NOx reacting with water to form H2SO4 and HNO3
- C Gradual depletion of the protective stratospheric ozone layer
- D Heavy metal contamination accumulating gradually within rainwater
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Answer: B. SO2 and NOx reacting with water to form H2SO4 and HNO3
Why: Acid rain: SO2 and NOx (from burning fossil fuels) react with water vapor to form sulfuric and nitric acids in rain.
Medium — 5 questions
Q8.
Ex-situ conservation includes:
- A Designated wildlife sanctuaries within natural habitat
- B National parks protecting natural ecosystems
- C Zoos, botanical gardens, gene banks, seed banks
- D Biosphere reserves protecting natural habitat
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Answer: C. Zoos, botanical gardens, gene banks, seed banks
Why: Ex-situ conservation: preservation of species outside their natural habitat (zoos, botanical gardens, seed banks, cryopreservation). Complements in-situ conservation.
Q9.
Trophic cascade occurs when:
- A Mainly the removal of producers from the base of a food web over time
- B A change at one trophic level affects multiple levels (top-down or bottom-up effects)
- C Competition increasing specifically between exactly two competing species nearby
- D Mainly a change occurring at the very base of the food web structure
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Answer: B. A change at one trophic level affects multiple levels (top-down or bottom-up effects)
Why: Trophic cascade: changes at one trophic level ripple through the food web. E.g., removing wolves allows deer to overgraze, reducing vegetation.
Q10.
The IUCN Red List categories for threatened species include (from least to most risk):
- A Endangered, Vulnerable, Critically Endangered
- B Vulnerable, Endangered, Critically Endangered (CR being highest risk before Extinct in Wild)
- C Rare, Threatened, Endangered
- D Near Threatened, Vulnerable, Endangered, Critically Endangered
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Answer: D. Near Threatened, Vulnerable, Endangered, Critically Endangered
Why: IUCN categories in increasing risk: Least Concern, Near Threatened, Vulnerable, Endangered, Critically Endangered, Extinct in Wild, Extinct.
Q11.
The phosphorus cycle lacks a significant:
- A A significant, well-defined soil-based component present within the overall cycle
- B Atmospheric (gaseous) phase -- phosphorus does not enter the atmosphere as a gas
- C A significant, well-defined oceanic phase present within the overall global cycle
- D Any meaningful biological uptake of phosphorus by living organisms each season
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Answer: B. Atmospheric (gaseous) phase -- phosphorus does not enter the atmosphere as a gas
Why: Unlike carbon and nitrogen cycles, the phosphorus cycle has no gaseous phase. Phosphorus moves from rocks to soil to water to organisms and back.
Q12.
Island biogeography theory predicts that species richness on islands depends on:
- A The particular surface colour or visual appearance of the island itself overall
- B Island size and distance from the mainland (immigration and extinction balance)
- C Mainly the surrounding ocean water temperature near the island in question
- D Mainly the level of human settlement activity present on the island itself
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Answer: B. Island size and distance from the mainland (immigration and extinction balance)
Why: Island biogeography (MacArthur and Wilson): species richness is equilibrium between immigration rate (increases with proximity to mainland) and extinction rate (decreases with island size).
Hard — 4 questions
Q13.
The intermediate disturbance hypothesis proposes that species diversity is highest:
- A In largely undisturbed, mature climax plant and animal communities over time
- B At intermediate levels of disturbance frequency and intensity (not too high, not too low)
- C Specifically within highly and frequently disturbed environments, generally speaking
- D Mainly at the single maximum possible level of disturbance intensity observed
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Answer: B. At intermediate levels of disturbance frequency and intensity (not too high, not too low)
Why: Intermediate disturbance hypothesis (Connell): moderate disturbances prevent competitive exclusion while maintaining species coexistence. Too little disturbance: competitive exclusion reduces diversity. Too much: most species cannot persist.
Q14.
Metapopulation theory describes:
- A A single, large, and largely continuous population occupying one habitat with no spatial subdivision into separate patches anywhere
- B A network of semi-isolated local populations connected by limited dispersal (colonization and extinction dynamics)
- C Populations that are restricted mainly to oceanic islands, rarely including any mainland or terrestrial populations
- D Populations of species that live mainly in aquatic habitats, excluding most terrestrial and amphibious species
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Answer: B. A network of semi-isolated local populations connected by limited dispersal (colonization and extinction dynamics)
Why: Metapopulation (Levins): multiple subpopulations in patchy habitat connected by dispersal. Local populations go extinct; empty patches recolonized. Overall persistence depends on balance of colonization and extinction.
Q15.
Liebig law of the minimum states:
- A Growth is sometimes thought to be limited specifically by whichever nutrient is present in the greatest abundance overall
- B The scarcest essential nutrient relative to its requirement limits organism growth (limiting factor)
- C All essential nutrients are sometimes thought to contribute roughly equally to limiting an organism's growth rate
- D Organism growth is sometimes thought to be limited mainly by the single nutrient present in maximum supply available
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Answer: B. The scarcest essential nutrient relative to its requirement limits organism growth (limiting factor)
Why: Liebig law of the minimum: growth rate of an organism is determined by the one essential nutrient (or factor) that is in shortest supply relative to the requirement, regardless of others.
Q16.
Extinction debt describes:
- A Money that is formally owed by governments specifically to fund conservation efforts rather than describing any biological time-lag effect on species survival
- B Species that will eventually go extinct due to past habitat loss even if habitat destruction stops now (time lag in extinction)
- C Current extinction rates mainly, without any reference to past habitat loss, omitting the delayed effect that past habitat loss has on future extinctions
- D Mainly extinct mammal species, excluding birds, reptiles, and other taxa, excluding the many other taxonomic groups this delayed-extinction concept applies to
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Answer: B. Species that will eventually go extinct due to past habitat loss even if habitat destruction stops now (time lag in extinction)
Why: Extinction debt: species committed to extinction by past habitat loss but not yet gone. Small, fragmented populations are not immediately viable. Future extinctions are predictable from current habitat reduction.