Please refer to Ecosystem Class 12 Biology Important Questions with answers below. These solved questions for Chapter 14 Ecosystem in NCERT Book for Class 12 Biology have been prepared based on the latest syllabus and examination guidelines issued by CBSE, NCERT, and KVS. Students should learn these solved problems properly as these will help them to get better marks in your class tests and examinations. You will also be able to understand how to write answers properly. Revise these questions and answers regularly. We have provided Notes for Class 12 Biology Important Questions for all chapters in your textbooks.

Important Questions Class 12 Biology Chapter 14 Ecosystem

Objective Type Questions

Question. Which of the following come under Terrestrial ecosystem?
A. Forest
B. Grassland
C. Desert
D. Estuary
Options :
(a) All of these
(b) A, B, C
(c) B,C, D
(d) A, B, D

Question. In a pond ecosystem the abiotic component is
(a) Phytoplanktons
(b) Bacteria
(c) Water with dissolved organic content
(d) None of these

Question. The consumer in a pond ecosystem are represented by
(a) Solar light
(b) Zooplanktons
(c) Phytoplanktons
(d) Fungi

Question. In pond ecosystem fungi acts as
(a) Phytoplanktons
(b) Consumers
(c) Zooplanktons
(d) Decomposers

Question. In pond ecosystem flow of energy is
(a) Bidirectional
(b) Unidirectional
(c) Multidirectional
(d) None of these

Question. Primary production is expressed as
(a) g^-2
(b) kcal m^-2
(c) tonnes
(d) both 1 and 2

Question. Productivity is expressed in terms of
(a) G^-2 yr^-1
(b) kcal m^-2 and yr^-1
(c) both 1 and 2
(d) tones yr^-1

Question. Available Biomass for the consumption to heterotrophs is called
(a) Gross primary productivity
(b) Secondary productivity
(c) Net primary productivity
(d) None of these

Question. Primary productivity depends upon
(a) Plant species inhabiting a particular area
(b) Availability of nutrients
(c) Photosynthetic capacity of plants
(d) All of these

Question. The productivity of ocean is
(a) 170 millions tons
(b) 170* 10³ million tons
(c) 55* 10³ million tons
(d) none of these

Question. During decomposition complex organic matter is converted into
(a) Carbon dioxide
(b) Nutrients
(c) Water
(d) All of these

Question. Process of decomposition does not include which of the following
(a) Leaching
(b) Catabolism
(c) Humification
(d) Photosynthesis

Question. During catabolism what happens
(a) Water soluble inorganic nutrients go down in soil horizon and get precipitated
(b) Bacterial and fungi enzymes degrade detritus into simpler inorganic substances
(c) Both 1 and 2
(d) None of these

Question. Humus is
(a) Dark color
(b) White color
(c) Amorphous substance
(d) Both 1 and 3

Question. Degradation of humus by microbes and release of inorganic nutrients is called
(a) Fragmentation
(b) Leaching
(c) Mineralization
(d) Humification

Question. Decomposition of detritus wil be fast if it is
(a) Rich in lignin and chitin
(b) Rich in nitrogen and water soluble substances
(c) Contains less nitrogen and water soluble substances
(d) None of these

Question. Which of the following is not a producer of Terrestrial ecosystem?
(a) Herbaceous plant
(b) Woody plant
(c) Phytoplankton
(d) All are producers of terrestrial ecoystem

Question. Herbivores come in category of
(a) Primary consumers
(b) Secondary consumers
(c) Detritivores
(d) Producers

Question. Detritus food chain begin with
(a) Grass
(b) Dead organic matter
(c) Either one or two
(d) Both 1 and 2

Question. State the incorrect statements
(a) Decomposers meet their energy and nutrient requirements by degrading dead organic matter or detritus
(b) Decomposers secrete digestive enzymes that break down dead and waste materials into simpler inorganic materials
(c) Detritus food chain is never connected with grazing food chain
(d) Some of organisms of detritus food chain are prey to grazing food chain animals

Question. Food web is
(a) Food web is crop field with more than one crop
(b Internet site with food information
(c) Natural interconnection of food chains
(d) None of these

Question. Match the following

Column – I	Column – II
A. Producers	I. Second trophic level
B. Carnivores	II. First trophic level
C. Herbivores	III. Third trophic level

Options :
(A) A – III, B – II, C – I
(B) A – II, B – I, C – III
(C) A – II, B – III, C – I
(D) A – III, B – I, C – II

Question. State the correct sentence
(a) The amount of energy increases at successive trophic levels
(b) When any organism dies it is converted to detritus or dead Biomass.
(c) Dead Biomass serves as an energy source for consumers
(d) Organism at each trophic level depend on those at higher trophic level for their energy demands.

Question. Measurement of biomass is more accurate in terms of
(a) Fresh weight
(b) Dry weight
(c) Fresh +dry weight
(d) None of these

Question. Which of the following is a ecological pyramid?
(a) Pyramid of biomass
(b) Pyramid of energy
(c) Pyramid of number
(d) All of these

Question. In an ecological pyramid the apex represents the
(a) Primary consumer
(b) Secondary consumer
(c) Producer
(d) Top consumer

Question. The pyramid of Biomass in sea (phytoplanktons —>fishes—>large fishes) will be
(a) Inverted
(b) Upright
(c) May be inverted or upright
(d) Straight

Question. The gradual and fairly predictable change in species composition of a given area is called
(a) Oofd chain
(b) Oofd web
(c) Ecological succession
(d) None of these

Question. The change in structure and composition of community is constantly in response to changing environmental conditions and is
(a) Orderly
(b) Sequential
(c) Parallel to environment change
(d) All of these

Question. In an Ecological succession in the succesive seral stage there is change in
(a) Diversity of species and organisms
(b) Increase in number of species and organisms
(c) Increase in total Biomass
(d) All of these

Question. Type of succession that starts at a place which have lost all living organism that existed there is known as
(a) Primary succession
(b) Secondary succession
(c) Tertiary succession
(d) All of these

Question. State the incorrect statement
(a) Since some soil sediment is present, secondary succession is faster than primary succession
(b) Description of ecological succession usually focuses on changes in vegetation
(c) As succession proceeds the number and type of animals and decomposition remains constant
(d) Natural or human induced disturbances fire deforestation etc can convert a particular seral stage of succession to an earlier stage

Question. In hydrarch succession series progresses from
(a) Xeric to mesic conditions
(b) Mesic to xeric conditions
(c) mesic to hydric conditions
(d) none of these

Question. Lichens help in weathering of rocks and soil formation by
(a) Secreting alkaline solutions that dissolve rocks
(b) Acids that dissolve Rocks
(c) By expanding underground
(d) None of these

Question. The correct sequence for primary succession for water body conversion to land is
A. Free floating angiosperms
B. Phytoplanktons
C. Trees
D. Rooted hydrophtes
E. Sedges
Options :
(a) A,D,E,C,B
(b) B,D,E,C,A
(c) B,A,E,D,C
(d) B,A,D,E,C

Question. Which of the following is true?
(a) Succession taking place in water ends in hydrarch succession
(b) Succession taking place on land ends in xeric community
(c) Succession taking place in either water or land ends in mesic community
(d) None of these

Question. Movement of nutrient element through the various components of ecosystem is called
(a) Xeric succession
(b) Mesic succession
(c) Biogeochemical cycles
(d) None of these

Question. Sulphur cycle comes under
(a) Sedimentary nutrient cycle
(b) Gaseous nutrient cycle
(c) Both 1 and 2
(d) None of these

Question. Which of the environmental factor regulate the rate of release of nutrient into atmosphere?
(a) Soil and moisture
(b) pH
(c) Temperature
(d) All of these

Question. Carbon constitutes what percentage of living organisms
(a) 75%
(b) 25%
(c) 80%
(d) None of these

Question. Carbon cycling occurs through
(a) Atmosphere
(b) Ocean
(c) Living and dead organism
(d) All of these

Question. Carbon dioxide returns to atmosphere via
(a) Respiratory activity of producer and consumers
(b) Processing of waste material and dead organic matter of land or Ocean
(c) Burning of wood forest combustion of organic material fossil fuel volcanic activity
(d) All of these

Question. Phosphorus is a constituent of
(a) Nucleic acids and biological membranes
(b) Elements of Shell and teeth in certain organisms
(c) Cellular energy transfer system
(d) All of these

Question. Which of the following is a difference between carbon and phosphorus cycle?
(a) Atmospheric input of phosphorus through rainfall are larger than that of carbon
(b) Exchange of phosphorus between organism and environment is more than that of carbon
(c) Phosphorus cycle is gaseous nutrient cycle
(d) Reservior of Phosphorus cycle is rocks

Question. Healthy forest ecosystem services include
A. Pure air, water, mitigate droughts and floods
B. Cycle nutrients and generate soil fertility
C. Provide wildlife habitat, maintain biodiversity
D. Provide aesthetics, cultural and spiritual vibes
Options :
(a) All of these
(b) A,B are true
(c) A,B,C,D are true
(d) only one statement is true