CBSE Questions for Class 12 Medical Biology Ecosystem Quiz 5 - MCQExams.com

The factors that affect ecological succession are 
  • Topography
  • Soil 
  • Climate 
  • All of the above 
If a grasshopper is eaten by a frog, then the energy transfer will be from 
  • Producer to decomposer
  • Producer to primary consumer
  • Primary consumer to secondary consumer
  • Secondary consumer to primary consumer
Which of the following is not a group of man-made ecosystems ? 
  • Forest and grassland ecosystems
  • Desert and pond ecosystems
  • Crop field and aquarium
  • River and estuary
Secondary productivity is the rate of formation of new organic matter by _____.
  • Producer
  • Parasite
  • Consumer
  • Decomposer
Primary succession begins with 
  • ants
  • lichens 
  • reptiles 
  • algae 
Both, hydrarch and xerarch successions lead to
  • Medium water conditions
  • Xeric conditions
  • Highly dry conditions
  • Excessive wet conditions
The pyramid of number in tree ecosystem
  • Inverted
  • Upright
  • Both
  • None
In grassland ecosystem the pyramid of biomass is
  • Linear
  • Upright
  • Inverted
  • Inverted upright
The biomass available for consumption by the herbivores and the decomposers is called __________.
  • Secondary productivity
  • Standing crop
  • Gross primary productivity
  • Net primary productivity
Source of maximum sulphur in reservoir of sulphur is
  • Ocean
  • Lakes
  • Rocks
  • Both A and C
Pyramid of numbers in grass ecosystem is
  • Linear
  • Upright
  • Inverted
  • Negative
Last stage of plant succession is
  • Ecotype
  • Seral community
  • Climax community
  • Ecotone
Most primary productivity of pond is by
  • Phytoplankton
  • Zooplankton
  • Floating plants
  • Red algae
Lichen is pioneer in ........................ succession. 
  • Hydrosere
  • Lithosere
  • Xerosere
  • Both B and C
Highest annual net primary productivity is of
  • Tropical deciduous forest
  • Temperate evergreen forest
  • Temperate deciduous forest
  • Tropical rain forest
In upright pyramid of biomass, herbivores occupy the position
  • 1
  • 2
  • 3
  • 4
In autogenic succession
  • Community itself modifies its own environment, thus causing its own replacement by new commuity
  • Early dominance of heterotrophs
  • Replacement of existing communites due to external conditions
  • Early and continued dominance of autotrophic organisms
Different communities appearing and replacing one another are called 
  • Climax community
  • Seral communites
  • Pioneer community
  • Successive communites
Solar energy can be trapped to the maximum capacity by
  • Planting trees
  • Crops
  • Grasses
  • Xerophytic plants
The energy storage at consumer level is known as
  • Gross primary productivity
  • Secondary productivity
  • Net primary productivity
  • Net productivity
Biogeochemical cycles are also known as
  • Cycles of matter
  • Sedimentary cycles
  • Material cycling
  • Gaseous cycles
The pyramid of biomass is inverted in
  • Pond ecosystem
  • Grassland ecosystem
  • Forest ecosystem
  • All of the above
Which of the following has the maximum number of producer per unit area?
  • Pond ecosystem
  • Grassland
  • Desert
  • Both A and B
An ecological pyramid of biomass is often an inverted pyramid in which of following ecosystem?
  • Desert
  • Ocean
  • Tundra
  • Rain forest
About how much, of net primary productivity of an aquatic ecosystem is eaten and digested by herbivores?
  • 1%
  • 10%
  • 40%
  • 90%
Which of the following elements have only the sedimentary type of nutrient cycle?
  • Carbon
  • Hydrogen
  • Nitrogen
  • Phosphorus
Which of the following is a sedimentary cycle?
  • Carbon
  • Hydrogen
  • Nitrogen
  • Phosphorus
In a grassland ecosystem, the shape of pyramid of number is
  • Linear
  • Irregular
  • Upright
  • Inverted
Plant maintains the balance of ......... in the atmosphere.
  • Oxygen
  • Carbon dioxide
  • Oxygen and Carbon dioxide
  • None of these
In a pyramid _________ constitute the largest number of organisms.
  • Decomposers
  • Consumers
  • Primary consumers (herbivores)
  • Producers
In a natural ecosystem, the biomass of herbivores will be .......... the biomass of carnivores.
  • Independent of
  • Greater than
  • Lesser than
  • The same as
In a parasitic food chain, the pyramid of number is
  • Linear
  • Upright
  • Spindle shaped
  • Inverted
The diagram below represents a biomass pyramid.
Which statement concerning the energy in this pyramid is correct ?

382812_d9c026905d3245d8820fc12c9cc8196a.png
  • The producer organisms contain the least amount of stored energy.
  • Stored energy decreases from consumer 3 to consumer 2.
  • Consumer 3 contains the least amount of stored energy.
  • Stored energy increases from the producer to consumers 1.
A biomass pyramid is important because it illustrates
  • The biomass of all organisms at each trophic level in a system
  • The number of trophic levels in a system
  • The number of species in each trophic level
  • How energy flows through a food web
The natural cycle that circulates elements between the earth and the environment is called as 
  • Biological cycle
  • Chemical cycle
  • Biogeochemical cycle
  • None of the above
Biogeochemical cycles can be traced in 
  • Ecosystems
  • Biomes
  • Only water
  • Both A and B
Mark the correct statement
a) Microbes helps in decomposition process
b) They help in maintaining biogeochemical cycle
c) Microbes only helps in carbon cycle, they don't have any role in nitrogen cycle
  • a, b
  • a, c
  • b, c
  • All
Which of the following process is involved in the processing of manures?
  • The decomposition of animal excreta
  • Plant waste
  • Above both options are correct
  • None of these
In the earths crust carbon is found in the form of
  • Carbonates
  • Hydrogen carbonates
  • Petroleum
  • All of the above
The rate of decomposition of hydrogen peroxide can be slowed down through
  • Glycerin
  • Manganese oxide
  • Vanadium oxide
  • Platinum
Which gas is utilised in combustion process ?
  • Carbon dioxide
  • Nitrogen
  • Oxygen
  • Water vapour
Biogeochemical cycles
  • Include the processes only conducted by or within living organisms
  • Pertain only to the abiotic environment
  • Describe the movement of water and other materials throughout the abiotic and biotic environment
  • Are used to describe the attempts of humans to recycle various pollutants
The atomic no. of carbon is ________
  • 5
  • 6
  • 12
  • 14
Sunlight is present for only a short span of time in 
  • Polar regions
  • Subtropical regions
  • Desert regions
  • Himalayan region
An ecosystem, such as an aquarium, is self-sustaining if it involves the interaction between organisms, a flow of energy, and the presence of 
  • Equal numbers of plants and animals
  • More animals than plants
  • Materials cycles
  • Pioneer organisms
Desert can be converted into a lush green land by planting
  • Terrestrial plant.
  • Mesophytic plant.
  • Halophytes.
  • Psammophytes.
During photosynthesis, the gross primary productivity is the rate of production of 
  • Organic matter
  • Oxygen
  • Carbon dioxide
  • Chlorophyll
Which of the following is the correct order of flow of energy?
  • Plants--> tigers--> microbes--> goats
  • Plants--> goats--> tigers--> microbes
  • Tiger--> plants--> microbes--> goats
  • Microbes--> tigers--> goats--> plants
Biogeochemical cycle involves .......... factors.
  • Biological
  • Geological
  • Chemical
  • All of the above
Eco-efficiency helps in achieving improved _______
  • Recyclability
  • Maturity
  • Development
  • Bio-accumulation
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