Ecology — MCQs Biology – T4Tutorials .PK

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1. Ecology is the study of:
(A) Interactions between organisms and their environment
(B) Structure of cells
(C) Human anatomy only
(D) DNA sequencing

2. A community in ecology refers to:
(A) Only plants in an area
(B) A single species population
(C) All populations of different species living together in a habitat
(D) Only microorganisms

3. An ecosystem includes:
(A) Only water bodies
(B) Only biotic components
(C) Both biotic and abiotic components
(D) Only sunlight

4. Producers in an ecosystem are:
(A) Decomposers
(B) Organisms that consume other organisms
(C) Autotrophs that synthesize their own food
(D) Carnivores only

5. Primary consumers are:
(A) Decomposers
(B) Carnivores
(C) Omnivores
(D) Herbivores

6. Secondary consumers are:
(A) Producers
(B) Carnivores that feed on herbivores
(C) Decomposers
(D) Detritivores

7. Tertiary consumers feed on:
(A) Detritus
(B) Primary producers
(C) Secondary consumers
(D) Microbes only

8. Decomposers are important because they:
(A) Photosynthesize only
(B) Produce glucose
(C) Consume other animals
(D) Break down dead organic matter and recycle nutrients

9. Detritivores feed on:
(A) Dead organic matter
(B) Live prey only
(C) Plants only
(D) Sunlight

10. The food chain represents:
(A) Cycles of matter only
(B) Linear flow of energy from producers to consumers
(C) Photosynthesis only
(D) Nutrient absorption only

11. A food web represents:
(A) Decomposition process only
(B) Single species diet only
(C) Photosynthesis pathway
(D) Interconnected food chains in an ecosystem

12. Biomass refers to:
(A) Total number of organisms only
(B) Total mass of living organisms in a given area
(C) Energy in sunlight only
(D) Mineral content of soil

13. Ecological pyramid of numbers shows:
(A) Water cycle
(B) Energy flow
(C) Biomass only
(D) Number of organisms at each trophic level

14. Ecological pyramid of biomass shows:
(A) Total biomass at each trophic level
(B) Number of organisms only
(C) Energy flow only
(D) Sunlight distribution

15. Ecological pyramid of energy shows:
(A) Water content
(B) Number of organisms
(C) Biomass only
(D) Energy flow through trophic levels

16. The efficiency of energy transfer between trophic levels is:
(A) 10% approximately
(B) 50%
(C) 90%
(D) 100%

17. Biogeochemical cycles involve:
(A) Only energy transfer
(B) Movement of elements between biotic and abiotic components
(C) Only DNA replication
(D) Only photosynthesis

18. The carbon cycle includes:
(A) Water evaporation only
(B) Nitrogen fixation only
(C) Photosynthesis, respiration, and decomposition
(D) Protein synthesis

19. Nitrogen fixation is carried out by:
(A) Animals only
(B) Fungi only
(C) Rhizobium and cyanobacteria
(D) Viruses

20. Denitrification converts:
(A) Nitrates into atmospheric nitrogen
(B) Nitrogen into ammonia only
(C) Ammonia into oxygen only
(D) Proteins into DNA

21. Phosphorus cycle does not involve:
(A) Atmospheric phase
(B) Soil, water, and organisms
(C) Rock weathering
(D) Decomposition

22. Oxygen in the environment is replenished by:
(A) Decomposition only
(B) Respiration only
(C) Combustion only
(D) Photosynthesis

23. Aquatic ecosystems are classified into:
(A) Forest only
(B) Desert only
(C) Grassland only
(D) Freshwater and marine ecosystems

24. Freshwater ecosystems include:
(A) Lakes, rivers, ponds, and wetlands
(B) Oceans only
(C) Mangroves only
(D) Forests only

25. Marine ecosystems include:
(A) Grasslands only
(B) Lakes only
(C) Oceans, coral reefs, and estuaries
(D) Deserts only

26. Terrestrial ecosystems include:
(A) Oceans only
(B) Forests, grasslands, deserts, and tundra
(C) Lakes only
(D) Rivers only

27. Biomes are:
(A) Large regions with similar climate, vegetation, and organisms
(B) Small ponds only
(C) Desert patches only
(D) Microorganisms only

28. Temperate forests are characterized by:
(A) Cacti and dry conditions
(B) Deciduous trees and seasonal climate
(C) Tundra vegetation
(D) Coral reefs only

29. Desert ecosystems are characterized by:
(A) Aquatic plants
(B) High rainfall only
(C) Low rainfall and drought-resistant vegetation
(D) Dense forests

30. Grasslands are dominated by:
(A) Trees only
(B) Grasses and herbaceous plants
(C) Cacti only
(D) Aquatic plants only

31. Tundra ecosystems have:
(A) Mangroves only
(B) High temperatures only
(C) Tropical forests only
(D) Low temperatures, permafrost, and sparse vegetation

32. Coral reefs are formed by:
(A) Mangroves only
(B) Trees only
(C) Cacti only
(D) Calcium carbonate secreting organisms like corals

33. Keystone species are:
(A) Only plants
(B) Species with no ecological role
(C) Species that have a large impact on ecosystem structure
(D) Only microbes

34. Invasive species are:
(A) Native species only
(B) Non-native species that disrupt local ecosystems
(C) Endangered species only
(D) Microbes only

35. Succession in ecology refers to:
(A) DNA replication
(B) Instant species change
(C) Gradual change in species composition over time
(D) Protein synthesis

36. Primary succession occurs on:
(A) Forest floor only
(B) Abandoned farmland
(C) Newly formed land with no previous life
(D) Oceans only

37. Secondary succession occurs on:
(A) Previously inhabited land after disturbance
(B) Newly formed rocks only
(C) Oceans only
(D) Deserts only

38. Climax community is:
(A) Temporary ecosystem
(B) Initial stage of succession only
(C) Stable, mature community at the end of succession
(D) Microbial colony only

39. Biodiversity refers to:
(A) Variety of life in all forms and levels
(B) Only species of plants
(C) Only animals
(D) Only microbes

40. Genetic diversity is:
(A) Variation in genes within a species
(B) Number of ecosystems only
(C) Species diversity only
(D) Soil diversity only

41. Species diversity refers to:
(A) Ecosystem types only
(B) Genetic variation only
(C) Number of different species in an area
(D) Soil microorganisms only

42. Ecosystem diversity refers to:
(A) Only microbial populations
(B) Number of species only
(C) Number of genes only
(D) Variety of ecosystems in a region

43. Endangered species are:
(A) Invasive species only
(B) Abundant species
(C) Keystone species only
(D) At risk of extinction

44. Conservation biology aims to:
(A) Preserve biodiversity and maintain ecosystem functions
(B) Produce antibiotics
(C) Ferment alcohol
(D) Sequence DNA only

45. Ecological footprint measures:
(A) Biomass only
(B) Energy in food chain only
(C) Human impact on the environment
(D) Soil nutrients only

46. Greenhouse gases include:
(A) CO₂, CH₄, and N₂O
(B) O₂ and N₂ only
(C) H₂O only
(D) NaCl only

47. Global warming is primarily caused by:
(A) Excess greenhouse gases
(B) Photosynthesis only
(C) Respiration only
(D) Decomposition only

48. Acid rain is caused by:
(A) CO₂ only
(B) Emission of SO₂ and NOₓ
(C) O₂ only
(D) Water only

49. Ozone layer depletion is due to:
(A) CFCs and halons
(B) CO₂ only
(C) Oxygen only
(D) Nitrogen only

50. Sustainable development aims to:
(A) Meet current needs without compromising future resources
(B) Exploit all natural resources
(C) Focus only on industry
(D) Focus only on agriculture