CBSE Questions for Class 12 Medical Biology Ecosystem Quiz 11 - MCQExams.com

One of the types of ecological pyramids is given here. This type represents ________.

929475_0bb7279e7f464b82a8e2ec9f2ed56e79.JPG
  • Pyramid of numbers in a grassland
  • Pyramid of biomass in a fallow land
  • Pyramid of numbers in a forest
  • Energy pyramid in a spring
The given pyramid shows the relative biomass of zooplanktons and phytoplanktons in a marine ecosystem.
The biomass of the zooplanktons is higher than that of the phytoplanktons because
929470_81d8c217d5764cd299b78ff0a2061607.JPG
  • the zooplanktons convert energy more efficiently
  • the zooplanktons have a shorter life cycle than the phytoplanktons
  • the phytoplanktons are individually much smaller than the zooplanktons
  • the phytoplanktons have an extremely high turnover rate.
During the process of ecological succession, the changes that take place in communities are:
  • Orderly and sequential
  • Random
  • Very quick
  • Not influenced by the physical environment
Productivity is the rate of production of biomass expressed in terms of-
(i) $$(kcal m^{-3})yr^{-1}$$
(ii) $$g^{-2}yr^{-1}$$
(iii) $$g^{-1}yr^{-1}$$
(iv) $$(kcal m^{-2})yr^{-1}$$
  • (ii)
  • (iii)
  • (ii) and (iv)
  • (i) and (iii)
Which of the following relations is correct regarding GPP and NPP of an ecosystem?
  • NPP = GPP - Animal consumption
  • NPP = GPP + Plant respiration
  • NPP = GPP - Plant respiration
  • NPP = GPP + Animal consumption
Primary succession on land occurs as:
  • lichen $$\rightarrow $$ mosses $$\rightarrow $$ annual grass $$\rightarrow $$ shrubs $$\rightarrow $$ trees
  • mosses $$\rightarrow $$ lichen $$\rightarrow $$ annual grass $$\rightarrow $$ shrubs $$\rightarrow $$ trees
  • plankton $$\rightarrow $$ submerged $$\rightarrow $$ floating stage $$\rightarrow $$ marsh stage $$\rightarrow $$ climax stage
  • all of these
A population in which number of pre-reproductive individuals is very large,number of reproductive individuals is moderate while post-reproductive individuals are fewer. Which kind of age pyramid is represented by such a population?
  • Cannot be determined
The rate at which light energy is converted into chemical energy of organic molecules, is the ecosystem's
  • net primary productivity
  • net secondary productivity
  • gross secondary productivity
  • gross primary productivity
In any one forest, if producers are 14000, then what will be the number of top carnivores?
  • 10
  • 140
  • 1400
  • 14
After a forest fire when above-ground plants are killed, which plant are the first to reappear?
  • Liverworts
  • Mosses
  • Ferns
  • Angiosperms
Two species competing for the same resource can avoid competition by choosing different habits. This phenomenon is called______ and was supported by _______ .
  • competitive exclusion, Gause
  • competitive exclusion , MacArthur
  • resource partitioning, Gause
  • resource partitioning, MacArthur.
NCERT
Autecology is the 
  • relation of heterogeneous population to its environment
  • relation of an individual to its environment
  • relation of a community to its environment
  • relation of a biome too its environment
The removal of keystone species will affect
  • producers
  • decomposers
  • ecosystem
  • Consumers.
Lichen is a pioneer in which succession?
  • Hydrosere
  • Lithosere
  • Psammosere
  • Xerosere
Secondary productivity is rate of formation of new organic matter by
  • Decomposers
  • Producers
  • Parasite
  • Consumer
Gross primary productivity is the rate of productivity of _______ during photosynthesis
  • organic matter
  • oxygen
  • carbon dioxide
  • chlorophyll
Highest net annual productivity occurs in  
  • Tropical rain forests
  • Tropical deciduous forests
  • Temperate evergreen forests
  • Temprate deciduous forests
Highest plant productivity occurs in
  • Desert
  • Temperature grassland
  • Trophical rain forest
  • Tundra
The given pyramid represents
1047653_68cbc1accd0c4eab8eed2f9982db11e6.PNG
  • Pyramid of energy in lake ecosystem
  • Pyramid of number in lake ecosystem
  • Pyramid of biomass in grassland ecosystem
  • Pyramid of biomass in lake ecosystem
In terms of the dry weight of organic matter, which of the following is related to the annual net primary productivity of the whole biosphere?
  • 12 billion tonnes
  • Environmental factor
  • Herbivore species
  • Availability of nutrients
Choose the correct sequence of transitional communities in Xerarch succession.
  • Mosses $$\rightarrow$$ Lichens $$\rightarrow$$ Grasses
  • Bryophytes $$\rightarrow$$ Forest $$\rightarrow$$ Shrubs
  • Bryophytes $$\rightarrow$$ Herbs $$\rightarrow$$ Shrubs
  • Lichens $$\rightarrow$$ Mosses$$\rightarrow$$ Herbs
An ecosystem receives $$1,000,000 J$$ of sunlight energy, then what is the energy available at primary producer $$(T_1)$$ level?
  • $$10,000 J$$
  • $$1,00,000 J$$
  • $$1,000 J$$
  • $$100 J$$
The different steps involved in the process of decomposition of detritus are
  • Fragmentation 
  • Leaching and Catabolism
  • Humification and mineralization
  • All of the above
Which of the following is an example of primary succession?
P. Freshwater lake
Q. Bare rock
R. Sand-dune
S. Abandoned field
  • $$P, R, S$$
  • $$P, Q, S$$
  • $$P, Q, R$$
  • $$Q, R, S$$
If tree = A, large Birds = B, Insects = C and small birds = D, then in a single tree ecosystem, the pyramid of number stays correct in all of the following except
  • C > D > A
  • D > A > B
  • C > B > A
  • D > B > C
Which of the following ecological food chain does not represent an erect pyramid of numbers?
  • Grass - Rodent - Snake
  • Insect - Chicken - Human
  • Tree - Bird - parasite
  • Grass - Deer - Tiger
The transfer of energy through a terrestrial ecosystem is often depicted by energy pyramids. Which of the following statement is true? 
  • Ecological efficiency is higher for top consumer.
  • About $$10\%$$ of the energy from one tropic level is incorporated into biomass of the next trophic level.
  • The energy lost as heat or in cellular respiration is $$10\%$$ of the available energy of each trophic level.
  • Only $$25\%$$ of the energy in one trophic level is passed onto the next level.
The gradual and fairly predictable change in species composition of a given area is
  • Ecological succession
  • Climax community
  • Pioneer species
  • Stratification
In establishing new ecosystem on rock the pioneers are
  • Lichens
  • Phytoplankton
  • Trees
  • Animals
Which pyramids is always upright, can never be inverted?
  • Pyramid of energy
  • Pyramid of biomass
  • Pyramid of number
  • Pyramid of dry biomass

Which of the following options shows a likely food chain represented by given pyramid of number?


1101380_e75cbface1a7452ca0c9469fe3a9916b.png
  • Phytoplankton $$\rightarrow$$ zooplankton $$\rightarrow$$ shellfish $$\rightarrow$$ fish $$\rightarrow$$ shark
  • Maize $$\rightarrow$$ rat $$\rightarrow$$ snake $$\rightarrow$$ meerkat $$\rightarrow$$ lion
  • Tree $$\rightarrow$$ aphid $$\rightarrow$$ ladybug $$\rightarrow$$ bird $$\rightarrow$$ hawk
  • Cyanobacteria $$\rightarrow$$ shrimp $$\rightarrow$$ fish $$\rightarrow$$ kingfisher $$\rightarrow$$ snake
In hydrarch succession, reed swamp stage is preceded by 
  • Forest community
  • Scrub stage
  • Sedge meadow stage
  • Floating stage
Which of the following organisms were not given any place in ecological pyramids? 
  • Saprophytes/Decomposers
  • Producers
  • Parasites
  • Carnivore
Which of these basic processes are constantly occurring in an ecosystem?
  • Energy flow and storage of energy
  • Storage of energy and release of energy
  • Photosynthesis and storage of energy
  • Energy flow and nutrient cycle
The rate at which new tissues are formed in producers in the ecosystem:-
  • NPP
  • GPP
  • Net secondary productivity
  • Gross secondary productivity
Maximum Reproduction capacity is shown by?
  • Pyramid of number
  • Pyramid of Biomass
  • Pyramid of energy
  • Both $$1$$ and $$2$$ above
In Grassland ecosystem, pyramid is upright type for?
  • Number
  • Biomass
  • Energy
  • All are upright pyramids
In an area undergonle process of succession, which community has highest rate of organic matter storage after consumption of heterotrophs:-
1149721_ebdf6f49eaba4776bb3994d6c24403b2.PNG
  • W
  • X
  • Y
  • Z
Description of ecological succession usually focuses on changes in
  • Animals
  • decomposers
  • Vegetation
  • All of the above
The upright pyramid of number is absent in
  • Grassland
  • Pond
  • Forest
  • Lake
Net primary productivity is defined as?
  • Total amount of food stored by producers
  • Maximum available biomass of heterotroph consumption
  • Total amount of food stored by plants after herbivore consumption
  • Rate of formation of new organic matter by consumers
Pyramid of Biomass indicates?
  • Biotic potential
  • Standing crop
  • Standing state
  • Productivity
Identify the biogeochemical cycle shown in the above figure?
1174980_1461afeb17e44356a59c6b5ad0157633.png
  • Oxygen cycle
  • Nitrogen cycle
  • Nitrogen fixation cycle
  • Carbon cycle
Which one is not causes of secondary succession
  • Overgrazing
  • Shifting
  • Agricultural practices
  • Sand dunes
During succession(from pioneer to climax community) NCP(Net Community Productivity) __________ .
  • Decrease
  • Increase
  • First increase then decrease
  • Constant
Sedge meadow stage and reed swamp stage are several stages seen in.
  • psammosere
  • lithosere
  • hydro-sere
  • aerosere
_____ is the basic unit of ecological hierarchy.
  • Gene
  • Species
  • Individual
  • Animals
Which of the following is limiting factor in the productivity of the ocean:-
  • NItrogen
  • Phosphorous
  • Magnesium
  • Both A and B
Which one is the Sedimentary Cycle?
  • Oxygen Cycle
  • Nitrogen Cycle
  • Hydrogen Cycle
  • Phosphorus Cycle
Functional aspect of ecosystem is?
  • Topography
  • Homeostasis
  • Inorganic nutrients
  • Species compositions
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