Ecosystem Questions

We provide ecosystem practice exercises, instructions, and a learning material that allows learners to study outside of the classroom. We focus on ecosystem skills mastery so, below you will get all questions that are also asking in the competition exam beside that classroom.

Ecosystem Questions

List of ecosystem Questions

Question NoQuestionsClass
1Read the following five statements (A to
E) and select the option with all correct
statements:
This question has multiple correct options
A. Mosses and Lichens are the first organisms to colonise a bare rock
B. Selaginella is a homosporous pteridophyte
c. Coralloid roots in cycas have VAM
D. Main plant body in bryophytes to gametophytes, male present within sporangia located on sporophyte
12
2Assertion
Phytoplankton, algae ( & ) higher plants are chief producers in pond ecosystem.
Reason
Many algae are responsible for
production of ethanol.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
c. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect
12
3The term biocoenosis was coined by
A. Darwin
B. Haeckel
c. Odum
D. Mobius
12
4Starting from a bare rock or a site of
volcanic eruption trace the organisms
that participate in the process of succession.
12
5An ecosystem contains
A. only the biotic components of the environment
B. only the energy flow components of an environment
C. both the living organisms and the abiotic components of the environment
D. only the food relationships found m an environment
12
6A black bear that eats berries and fish
would be classified as
A. A producer
B. An omnivore
c. A carnivore
D. An herbivore
E. An autotroph
12
7Ecosystem creates
A. Food chains and food web
B. Food web
c. Habitats
D. None of the above
12
8An ecosystem is an interacting system
of
A. Communities
B. Communities and their physical environment
c. Populations
D. Individuals
12
9The primary succession in a sere is a
A. Sub sere
B. Meso sere
c. Pioneer sere
D. None of the above
12
10In autogenic succession,
A. The community itself modifies its own environment thus causing its own replacement by a new community.
B. Early dominance of heterotrophs.
C. Replacement of existing communities due to external conditions.
D. Early and continued dominance of autotrophic organisms.
E. There is previously built substratum with already existing matter.
12
11Choose the correct statement about
ecological succession.
A. It is a natural progression of plant types that cannot be reversed.
B. It always occurs over a short period of time.
C. The rate can be changed by factors such as fire, clear cutting, and lava flows.
D. It only takes place on freshly cleared or new land such as islands.
E. The rate is very slow and constant.
12
12Ecosystem of a pond is
A. Lotic
B. Lentic
c. Benthic
D. Xeric
12
13A community, which starts succession in a habitat is
A. Pioneer community
B. Seral community
c. Biotic community
D. Ecosere
12
14An ecosystem is characterized by which of the following
A. Energy flow
B. Autotrophs converting solar energy to organic compounds
c. Decomposers recycling organic matter to inorganic compounds
D. All of the above
12
15Select the correct sequence of
succession in a pond
A. Submerged plants ( rightarrow ) Floating plants ( rightarrow ) Reed swamp stage ( rightarrow ) Sedges
B. Floating plants ( rightarrow ) Submerged plants ( rightarrow ) Reed swamp stage ( rightarrow ) Sedges
C. Reed swamp stage ( rightarrow ) Sedges ( rightarrow ) Floating plants ( rightarrow ) Submerged plants
D. Sedges ( rightarrow ) Reed swamp stage ( rightarrow ) Floating plants ( rightarrow ) Submerged plants
12
16toppr ( E )
Q Type your question
B.
( c )
( D )
12
17Instead of excreting, these can store urea in the tissues
A. Birds
B. Fish
c. Elephants
D. camels
12
18Assertion
Secondary succession takes place in
recently denuded area.
Reason
It is caused due to baring of an area.
A. Both Assertion and Reason are correct and Reason is
the correct explanation for Assertion.
B. Both Assertion and Reason are correct but Reason is
not the correct explanation for Assertion.
C. Assertion is correct but Reason is incorrect.
D. Both Assertion and Reason are incorrect.
12
19Animals, plants and bacteria are
A. biotic component
B. abiotic component
c. renewable component
D. non-renewable component.
12
20Ine aata glven In the table snows species richness of mosses, shrubs and trees calculated for one hectare
( left(10,000 m^{2}right) ) of land every 50 years for
200 years based on a long running
ecological study. According to the data natural disaster
occurred during which time period?
( begin{array}{llll}text { Year } & text { Mosses } & text { Shrubs } & text { Trees } \ 1800 & 16 & 2 & 0 \ 1850 & 21 & 7 & 4 \ 1900 & 10 & 5 & 3 \ 1950 & 13 & 12 & 6 \ 2000 & 17 & 28 & 14end{array} )
A . ( 1750-1800 )
B. 1800-1850
c. ( 1850-1900 )
D. 1900-1950
E ( 1950-2000 )
12
21The life forms in aquatic biomes are dependent on
A. Sunlight
B. Salt
c. Pressure
D. All of the above
12
22Ecesis is
A. Establishment of a plant in a new place
B. A condition of equilibrium
C . Climax
D. Invasion of a number of plants
12
23State whether the following statements are true or false.
Ecological succession is directional therefore a predictable process
A. True
B. False
12
24Desert can be converted into green land by planting
A. Oxylophytes
B. Psammophytes
c. Halophytes
D. Green trees
12
25Biotic community along with its interacting physical environment comprises
A. Phytosociology
B. Phytogeography
c. Ecosystem
D. Ecology
12
26Keystone species is of
A. Always dominant
B. Useful in maintaining structure and function of biotic community
c. with maximum biomass
D. All the above
12
27The food chain in which microbes
breakdown, energy rich compounds, synthesized by producers is called as
A. Ecosystem
B. Parasitic food chain
c. Detritus food chain
D. Predator food chain
12
28Climax vegetation of a region is generally
A. Xerophytic
B. Hydrophytic
c. Mesophytic
D. Depends upon the climate
12
29Which one of the following Clements would consider to be the climax
community in a humid environment?
A. The pioneer community
B. Lichens, mosses, and ferns
c. Large plants such as shrubs and trees
D. Small native plants of the area such as grasses and herbs
12
30Last stable community is succession which depends on climate is
A. Seral community
B. Climax community
c. Poineer community
D. None of the above
12
31A scorpion stalks kills and then eats a spider. Based on its behaviour which ecological terms describe the scorpion?
A. Producer, Herbivore, Decomposer
B. Producer, Carnivore, Heterotroph
c. Predator, Carnivore, Consumer
D. Predator, Autotroph, Herbivore
12
32Most animals that live in deep oceanic
waters are
A. Primary consumers
B. Secondary consumers
c. Tertiary consumers
D. Detrivores
12
33All the interacting organisms in an area together with the non-living constituents of the environment form
an
12
34What is difference between habitat and
ecosystem?
12
35Define :
a) ecosystem services
b) sere
c) BOD
12
36Different communities appearing and replacing one another are called
A. Climax communities
B. Seral communities
c. Serial communities
D. successive communities
12
37Succession showing changes in communities at a place is called
A. Geographical succession
B. Biotic succession
C. Physiographic succession
D. climatic succession
12
38What is maximum in a pond-
ecosystem?
A. Primary consumers
B. Secondary consumers
c. Producers
D. Decomposers
12
39Abiotic component in an ecosystem is
A. water
B. Daphnia
C. Bacteria
D. chlorella
12
40Which of the following is the most stable ecosystem?
A. Mountain
B. Desert
c. Forest
D. Ocean
12
41Draw a lake showing different zones.
Why are they called so?
12
42Free services provided to humans by
ecosystems include
A. control of atmospheric carbon dioxide concentration
B. prevention of soil erosion
c. filtering of pollutants from water and air.
D. all of the above
12
43Earliest settlers on barren lands or the
‘farmers of nature’ are
A. Diatoms
B. Lichens
c. Moss and grasses
D. Ferns
12
44The utilization of nitrogen as nitrogen
( operatorname{gas}left(N_{2}right) ) can be done by
A. Producers
B. Primary consumers
c. Secondary consumers
D. Tertiary consumers
E. Decomposers
12
45The amount of usable energy remains
constant as it is passed from one trophic level to another.
A. True
B. False
c. Either
D. Neither
12
46The term ecosystem was coined by
A. Warming
B. Odum
c. tansley
D. Haeckel
12
47Differentiate between :
Biotic and abiotic components of an
ecosystem
12
48What are micro-consumers?12
49In forest, trees basically function as12
50Choose the correct from the alternatives
given Which one of the following organisms is the first to colonise a bare rock?
A . Lichens
B. Mosses
c. Perennial plants
D. Metazoans
12
51Lichen is a pioneer in which succession?
A. Hydrosere
B. Lithosere
c. Psammosere
D. Xerosere
12
52Choose the correct answers from the
alternatives given Which of the following forms of energy is not correctly matched?
A. Kinetic energy fat molecules
B. Kinetic energy: movement of muscles
c. chemical energy: glucose
D. Potential energy ATP
12
53Who proposed the term ecosystem?
A. Odum
B. Gardner
c. Warming
D. Tansley
12
54Biotic component of biosphere is not constituted by
A. Producers
B. Consumers
c. Decomposer
D. Air
12
55Nature of climax community depends
upon
A. water
B. Temperature
c. Soil fertility
D. Climate
12
56How does an age pyramid for human population at given point of time helps the policy makers in planning for future?12
57In autogenic succession
A. Community itself modifies its own environment, thus causing its own replacement by new commuity
B. Early dominance of heterotrophs
C. Replacement of existing communites due to external conditions
D. Early and continued dominance of autotrophic organisms
12
58The correct sequence of plants in a
hydrosere is?
( mathbf{A} cdot ) Volvox ( rightarrow ) Hydrilla ( rightarrow ) Pistia ( rightarrow ) Scirpus ( rightarrow ) Carex ( rightarrow ) Quercus
B. Pistia ( rightarrow ) Volvox ( rightarrow ) Scirpus ( rightarrow ) Hydrilla ( rightarrow ) Quercus ( rightarrow ) Carex
C. Quercus ( rightarrow ) Carex ( rightarrow ) Volvox ( rightarrow ) Hydrilla ( rightarrow ) Pistia ( rightarrow ) Scirpus
D. Quercus ( rightarrow ) Carex ( rightarrow ) Scirpus ( rightarrow ) Pistia ( rightarrow ) Hydrilla ( rightarrow ) Volvox
12
59The productive area required to produce all the resources for humanity to consume and to absorb all its waste is
known as
A. A habitat
B. An ecosystem
c. An ecological footprint
D. The biosphere
E. The carrying capacity
12
60A keystone species is the one which has
A. A small proportion of total biomass but has a huge impact on the community’s organisation and survival.
B. A plenty of biomass but low impact on community’s organisation.
C. A rare species with little impact on biomass and other species in the community.
D. A dominant species which has a large proportion of biomass and which affects many other species.
12
61Heavy rainfall during summer produces
A. Desert
B. Grassland
c. Forest
D. wetland
12
62Which food chain directly depends on solar radiations?
A. Predator
B. Grazing
c. Detritus
D. None of the above
12
63The atomic no. of carbon is
A. 5
B. 6
( c cdot 12 )
D. 14
12
64An ecosystem contains
This question has multiple correct options
A. Producers
B. Decomposers
c. Lentic
D. Xeric
12
65Ecosystem has two components. They
are
A. Trees and fungi
B. Living and non living
c. Plants and animals
D. None of these
12
66The pyramid of energy is the best representation of an ecosystem because it indicates
A. Relation of all plants and animals
B. Total energy present in an ecosystem
C. The rate of flow of energy through the food chain
D. None of the above
12
67Phytoplanktons are an important biotic
component of
A. Grassland ecosystem
B. Pond ecosystem
C. Forest ecosystem
D. None of the above
12
68Amount of energy transferred from one trophic level to next is
A . 1.5%
B . 10%
c. 15%
D. 20%
12
69Which of the following processes is responsible for the existence of a stream free of pollutants within a few miles downstream of a point at which a small amount of sewage is dumped into
it?
A. succession
B. Biological magnification
c. Evaporation
D. Photosynthesis
E. Decomposition
12
70Identify the correct statement for freshwater ecosystems.
I. There is a seasonal mixing
of materials.
II. During the year, oxygen concentrations are
vertically uniform.
III. Materials are recycled more quickly
than in ocean ecosystems.
A. I only
B. II only
C. III only
D. I and III
E. II and III
12
71a) Draw an ideal pyramid of energy and mention the units.
b) What is an ecological succession?
12
72An ecosystem is not a self-sufficient
unit
A . True
B. False
12
73Match the two sets
( mathbf{A} )
I- D, II- A, III- B, IV- C
B. I- A, II- B, III-C, IV-D
( mathbf{C} cdot mid-mathrm{B},|-mathrm{A},| mathrm{I}-mathrm{D}, mathrm{IV}-mathrm{C} )
D. ( |-A,| I-D,|I|-C, mid V-B )
12
74In hydrosere succession, which stage
comes just before sedge meadow stage?
A. Rooted submerged stage
B. Phytoplankton stage
c. Reed swamp stage
D. climax stage
12
75The partially decomposed organic matter is formed by a process called
A. Fragmentation
B. Humification
c. Mineralization
D. Leaching
12
76The study of fresh water ecosystem is called as
A. Limnology
B. Ethology
c. synecology
D. Autecology
12
77What are ecosystem services? What lessons do they give to human society?12
78Explain Biotic components of the Ecosystem.12
79Ecosystem is defined as
A. Relation between plants and animals
B. Relation between biotic and physical components
C . Relation between producers and decomposers
D. None of the above
12
80Lentic ecosystem occurs in
A. Rain water
B. Running water
c. standing water
D. Gravitational water
12
81Primary succession on land occurs as:
A. lichen ( rightarrow ) mosses ( rightarrow ) annual grass ( rightarrow ) shrubs ( rightarrow ) trees
B. mosses ( rightarrow ) lichen ( rightarrow ) annual grass ( rightarrow ) shrubs ( rightarrow ) trees
C. plankton ( rightarrow ) submerged ( rightarrow ) floating stage ( rightarrow ) marsh stage ( rightarrow ) climax stage
D. all of these
12
82A rocky barren land after some time
changes into fertile rich, crop yielding land. Which sequence might have
occured?
A. Lichens, mosses, shrubs, herbs
B. Lichens, mosses, herbs, shrubs
C. Mosses, herbs, shrubs, lichens
D. Herbs, shrubs, lichens, mosses
12
83Find out the correct order of succession
levels in xerarch.
A. Lichen, moss stage, annual herb stage, perennial herb stage, shrub stage, forest
B. Annual herb stage, perennial herb stage, lichen moss stage, shrub stage, forest
C. Perennial herb stage, annual herb stage, lichen moss stage, shrub stage, forest
D. Shrub stage, forest, annual herb stage, perennial herb stage, lichen moss stage
E. Forest, shrub stage, annual stage, perennial herb stage, lichen moss stage
12
84Which biological process is responsible for the appearance of these plants in a burned area?
A. Evolution by natural selection
B. Succession
c. Mutation
D. Eutrophication
E. Recombination
12
85(a) What is an ecosystem? List its two main components.
(b) We do not clean ponds or lakes, but an aquarium needs to be cleaned
regularly. Explain.
12
86The succession that starts on
abandoned crop land is
A. Primary succession
B. xerarch succession
c. secondary succession
D. Hydrarch succession
12
87Which features are characteristic of
insect-pollinated flowers?
A. Bright petals, large feathery stigmas
B. Bright petals, rough sticky pollen
c. Large feathery stigmas, nectaries
D. Small light pollen, nectarines
12
88In an ecosystem undergoing succession, replacement of a plant community takes place due to
A. Pollution
B. Herbivory
c. Parasitism
D. Abiotic factors
E. Intraspecific competition
12
89Which of the following terms defines the prefix ‘eco’?
A. Ecology
B. Environment
c. Adaptation
D. Exchange
12
90Secondary succession takes place on/in
A. Newly created pond.
B. Newly cooled lava.
c. Bare rock.
D. Degraded forest.
12
91Climax community is
A. First stable community
B. Unstable
c. unstable that develops in the beginning of succession
D. The last stable community
12
92Which is correct for secondary
succession?
A. It follows primary succession
B. It is similar but faster than primary succession
C. It begins on bare rock
D. It occurs on deforested site
12
93Second stage of hydrosere is occupied by plants like
A. salix
B. Vallisneria
c. Azolla
D. Typha
12
94Choose the correct answers from the
alternatives given :
Which of the following factors is least likely to affect the type of organism colonizing a pond
A. Acidity of water
B. Age of pond
c. Amount of rainfall
D. Amount of sunlight falling on the pond
12
95The term ecosystem development to ecological succession was given by
A. Odum
B. Clements
c. Mishra
D. Blackman
12
96Multiple Choice Questions Which statement is correct for pond
ecosystem
A. Pyramid of numbers is upright
B. Pyramid of mass is inverted
c. Pyramid of energy is upright
D. All the above
12
97Write down two special features of climax community.12
98Explain how xerarch succession progresses from xeric to mesic
condition and forms a stable climax
community.
12
99Ecological succession in a hydrosere
includes
A. Increase in species diversity
B. Increase in structural complexity
c. Increase in organic matter
D. All of the above
12
100The possible beneficial affect of grazing animals is the
A. Removal of wild animals
B. Eradication of weeds
C. Removal of wild plants
D. Addition of their excrete to the soil
12
101Which part of the pond ecosystem does not get affected by the temperature?
A. Epilimnion
B. Metalimnion
c. Hypolimnion
D. All of the above
12
102Biotic factors are
A. Chemical factors of soil which affect life
B. Physical factors of soil which affect life
C. All living organisms which influence other organisms
D. Factors of atmosphere which affect life
12
103In deep fresh water ponds, different layers of water with different temperatures are noticed. This is known
as
A. Thermal stratification
B. Surface tension
c. water equilibrium
D. Thermal equilibrium
12
104An extinct bird of Mauritius is the
( A ). Bubo
B. Dodo
c. Peacock
D. Pigeon
12
105Succession is
A. Orderly process of community change till stability
B. Gradual, directional and continuous process
C. Series of biotic communities that appear gradually in a barren area
D. All of the above
12
106a) What is ecological secession?
b) Represent an ideal pyramid of number in a grassland ecosystem.
c) Name the two types of nutrient cycles with an example each.
12
107Trace the succession of plants on. a dry
bare rock.
12
108During succession(from pioneer to climax community) NCP(Net Community Productivity)
A. Decrease
B. Increase
c. First increase then decrease
D. constant
12
109Algae and other submerged green plants often float in water during
daytime and sink at night because
A. Trapping of oxygen bubbles during the day in their photosynthesis
B. Release of absorbed air by warming of water
c. They become light due to the consumption of food
D. They come up to enjoy sunshine
12
110An ecosystem may be a small or a large sized based on kind of
A . Habit
B. Habitatat
c. components
D. Molecules
12
111Succession on secondary bare area is
A. Primosere
B. Xerosere
c. subsere
D. None of the above
12
112State whether the following statements
are true or false.
Climax indicates a final and stable community in a successional series
A. True
B. False
12
113As compared to seral communities, the number of niches in climax
communities would be
A. Same
B. Fewer and generalised
c. More and specialised
D. None of the above
12
114In plant succession, the net productivity of climax community
A. Continuous to increase
B. Becomes stable
c. Becomes halvedd
D. Reduced to ( 10 % )
E. Becomes zero
12
115Match Column-I with Column-II12
116The ecosystem services include.
A. Maintenance of biodiversity
B. Pollination of crop
C . Spiritual, cultural and aesthetic values
D. All of these
12
117When the two ecosystems overlap each other, the area is called as
A. Habitat.
B. Niche
c. Ecotone.
D. Ecotype.
12
118Early colonisers of bare and barren
areas helps in
succession
12
119What are the important factors that bring about biological diversity?
A. Temperature
B. Enviornment
c. climatic conditions
D. All of the above
12
120Bacteria and fungi belong to
A. Autotrophs
B. Primary consumers
c. Decomposers
D. Secondary consumers
12
121I ne aata glven in the table snows species richness of mosses, shrubs and trees calculated for one hectare
( left(10,000 m^{2}right) ) of land every 50 years for
200 years based on a long running
ecological study.
( begin{array}{llll}text { Year } & text { Mosses } & text { Shrubs } & text { Trees } \ 1800 & 16 & 2 & 0 \ 1850 & 21 & 7 & 4 \ 1900 & 10 & 5 & 3 \ 1950 & 13 & 12 & 6 \ 2000 & 17 & 28 & 14end{array} ) The ecological process occurring
according to the data is
A. Evolution
B. Succession
c. Destabilization
D. Primary growth
E . Artificial selection
12
122If carbon dioxide is withdrawn from the
biosphere, which organism would first experience negative effects?
A. Primary consumers
B. Producers
c. Secondary consumers
D. Tertiary consumers
12
123The carbon cycle is the movement of carbon on Earth by the processes of
and ( -cdots )
A. Plants and animalss
B. Respiration and photosynthesis
c. Breathing in and breathing out
D. Oxygen and carbon dioxide
12
124Which of the following is not a decomposer?
A. Fungi
B. Bacteria
c. Hyenas
D. Earthworms
E. Dung beetles
12
125The organisms dwelling at the bottom of a lake are called
A. Phytoplanktons
B. Zooplanktons
c. Nektons
D. Benthos
12
126An ecosystem includes
A. All living organisms
B. Non-living objects
C. Both living organisms and non – living objects
D. Sometimes living organisms and sometimes non living objects
12
127Which of the following is true of
ecological pyramids
A. Pyramids built upon biomass of organisms at each level eliminate size as a factor in the organisms
B. Energy gains between trophic levels occur based upon biomass conversion
C. limited number of trophic levels man ecological pyramid are due to increasing complexity and size of organisms at each greater trophic level
D. None of the above
12
128Energy enters a food chain through
A. Producers
B. Decomposers
c. Herbivores
D. Carnivores
12
129An ecosystem resists change because it is in a state of
A. Imbalance
B. Homeostasis
c. shortage of components
D. Deficiency of light
12
130Two components of ecosystem are
A. Plants and animalss
B. Trees and fungi
c. Living and non living
D. Frogs and man
12
131Different communities appearing and replacing one another are called as
A. Climax community
B. Seral communites
c. Pioneer community
D. successive communites
12
132Stages of hydrarch are
(a) Marsh meadow stage,
(b) Reed swamp stage,
(c) Submerged plant stage,
(d) Phytoplankton stage,
(e) Submerged free floating stage. Identify the correct sequence.
( A cdot d, c, e, b, a )
B. ( c, e, a, b, d )
c. ( b, d, c, ) a, e
D. ( mathrm{d}, mathrm{e}, mathrm{c}, mathrm{b}, mathrm{a} )
12
133In the food chain, Man is a
A. Producer
B. Consumer
c. Both producer and consumer
D. Producer and decomposer
12
134State whether the following statements
are true or false.
Humans often disrupt natural succession to produce agricultural fields and managed forests.
A. True
B. False
12
135Biodiversity must be conserved as it
plays an important role in many ecosystem services that nature provides. Explain any two services of the ecosystem
12
136The upper part of sea water mainly contains
A. Planktons only
B. Nektons only
c. Both nektons and planktons
D. None of the above
12
137The term ecosystem was used by
A. Tansley
B. Odum
c. Lamarck
D. Haeckel
12
138In an ecosystem, the biotic components herbivores are
A. Photosynthetic
B. Chemosynthetic
c. Macroconsumers
D. Microconsumers
12
139Importance of ecosystem lies in
A . Cycling opmaterials
B. Flow of energy
c. Both A and B
D. None of the above
12
140In ecotone which species become abundant?
A. Sibling species
B. Endemic species
c. Rare species
D. Edge species
12
141Find the incorrect match
( begin{array}{lll}text { । } & text { II } & text { III } \ text { i. Crab } & text { Sacculina } & begin{array}{l}text { Interaction } \ ++end{array} \ begin{array}{l}text { ii. Human } \ text { being }end{array} & text { Mosquito } & begin{array}{l}text { Interaction } \ -+end{array} \ begin{array}{l}text { iii. Sea } \ text { anemone }end{array} & begin{array}{l}text { Hermit } \ text { crab }end{array} & begin{array}{l}text { Interaction } \ ++end{array}end{array} )
A . i. only
B. ii. and iii.
c. iii. and
D. ii. only
12
142Assertion
Oceans and lakes tend to maintain a
relatively constant temperature.
Reason
Water has high heat capacity and it can withhold large amounts of heat.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
c. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect
12
143The difference between primary
succession and secondary succession
is that
A. Primary succession occurs on soil
B. Primary succession begins with lichens
C. Primary succession begins with plant species
D. secondary succession involves animal species
E. Secondary succession involves the weathering of rock
12
144Who coined the term ecosystem?
A. Tansley
B. Odum
c. Warming
D. Darwin
12
145If 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
( A cdot C>D>A )
B. ( D>A>B )
( c cdot c>B>A )
D. ( D>B>C )
12
146The only requirement of an ecosystem is a constant input of energy that comes by the process of respiration
A. True
B. False
12
147Anthropogenic ecosystems
A. show high degree of nutrient cycling
B. show low productivity
C . show great biodiversity
D. Do not posses self regulatory mechanism
12
148An ecosystem is a
A. group of components that interact with one another
B. group of interacting chemicals and their cycles
C . group of interacting species in one place at one time
D. biologic community and components of the physical environment with which the community interacts
12
149Choose the correct identification for the
given stage of succession and is preceded by which stage respectively?
Submerged free floating plant stage
A. Marsh-meadow, Reed-swamp
B. Submerged free floating, Read-swamp
c. Submerged plant, Scrub stage
D. Phytoplankton, Marsh-meadow
12
150During photosynthesis, the gross primary productivity is the rate of production of
A. organic matter
B. Oxygen
c. Carbon dioxide
D. chlorophyll
12
151Who confirmed communities with more
species tend to be more stable than those with less species?
A. Alexander von Humboldt
B. David Tilman
c. Paul Ehrlich
D. Edward Wilson
12
152Energy flow and energy transformations in living system strictly conform to the
A. Law of limiting factors
B. Liebig’s law of minimum
c. Laws of thermodynamics
D. Biogenetic law
12
153State whether the following statements are true or false.

After fire a primary succession starts at a very rapid rate
A. True
B. False

12
154Which one of the following can be considered as an example of secondary consumer?
A. A fish that feeds on algae
B. A hawk that feeds on a mouse that feeds on an insect
C. A plant that is parasitic to another plant
D. A lion that eats a gazelle that feeds on grass
E. A beetle that feeds on nectar
12
155The final stable community in ecological succession is
A. Seral community
B. Pioneer communiy
c. Ecosere
D. climax community
12
156An easily disturbed ecosystem which
can recover after sometime after the
stoppage of damaging factor, is of
A. Low stability and high resilience
B. High stability and high resilience
c. Low stability and low resilience
D. High stability and low resilience
12
157Which of the following is considered as pioneer community in xerarch?
A. Annual herb
B. Perennial herb
c. Scrub stage
D. Lichen
12
158Upper reaches of a river does not possess many living beings because of
A. Low temperature
B. High speedd
c. Both low temperature and high speed
D. Little depth
12
159Some students, during a study, caught marked and released 80 fish in a pond.
Later 100 fishes were caught at random. Among these 40 were found to be marked. What is the approximate number of fishes in the pond?
A . 50
B. 100
( c cdot 200 )
D. 4000
12
160Lichen is the pioneer vegetation on which succession?
A. Hydrosere
B. Lithosere
c. Psammosere
D. Xerosere
12
161Choose the correct answers from the
alternatives given. Some species of Anopheles mosquito live in brackish water, some in running fresh water, and others in
stagnant water. What type of reproductive barrier is most obviously separating these different species?
A. Ecological isolation
B. Temporal isolation
c. Behavioural isolation
D. Postzygotic barriers
12
162In an ecosystem, the function of the
producers is to
A. Convert organic compounds into inorganic compounds
B. Trap solar energy and convert it into chemical energy
C. Utilize chemical energy
D. Release energy
12
163Deserts can be converted into green
land by
A. Tropical trees
B. Oxylophytes
c. Halophytes
D. Psammophytes
12
164Select the mis-matched pair in the
following.
(a) Biomagnification- Accumulation of chemicals at the successive trophic
levels of a food
chain.
(b) Ecosystem- Biotic components of environment
(c) Aquarium- A man-made ecosystem.
(d) Parasites- Organisms which obtain
food from other living organisms.
( A cdot(a) ) and ( (b) )
B. Only (b)
c. ( (a),(b) ) and ( (c) )
D. Only (d)
12
165The last and stable community is an area is called
A. Pioneer community
B. Climax community
c. Transitional community
D. Seral community
12
166Succession is
A. Orderly process of community change till stability.
B. Gradual convergent, directional and continuous
process.
C. Series of biotic communities that appear generally in barren area.
D. All of the above.
12
167NCERT
Autecology is the
A. relation of heterogeneous population to its environment
B. relation of an individual to its environment
C. relation of a community to its environment
D. relation of a biome too its environment
12
168How do chlorofluorocarbons (CFSs)
enter the atmosphere and how do they affect humans? Explain.
12
169Which one is included under ecosystem
services?
A. Protection of soil
B. Conservation and purification of water
c. Climate control
D. All of the above
12
170The second stage of hydrosere is occupied by plants like
A . Azolla
B. Typha
c. salix
D. Vallisneria
12
171Ecosystems have
A. energy inputs and outputs
B. nutrient cycling but not outputs
C . one trophic level
D. both
(a) and (b)
12
172An American plant that had become a troublesome waterweed in India is
A. Trapa bispinosa
B. Cyperus rotundus
c. Eichhornia crassipes
D. Typha latifolia
12
173In the given figure, ( A, B, C, D, E ) and ( F )
represent some stages of hydrosere.
Select the correct statement regarding
these.
A. Hydrilla and Potamogeton occur in stage ( A ); Nymphaea and Nelumbo occur in stage B
B. Phragmites and Typha occur in stage ( C ; ) Carex and Cyperus occur in stage ( mathrm{D} )
C. Aluns and Populus occur in stage ( mathrm{E} ); Acer and Quercus occur in stage ( F )
D. All of these
12
174Write types of plant succession12
175The sequence of communities of
primary succession in water is?
A. Phytoplankton, sedges, free-floating hydrophytes, rooted hydrophytes, grasses and trees
B. Phytoplankton, free-floating hydrophytes, rooted hydrophytes, sedges, grasses and trees
C. Free-floating hydrophytes, sedges, phytoplankton, rooted hydrophytes, grasses and trees
D. Phytoplankton, rooted submerged hydrophytes, floating hydrophytes, reed swamp, sedges, meadow and trees
12
176Nature’s prime balancing and life supporting mechanism operates between
A. Photosynthesis and respiration
B. Evaporation and photosynthesis
c. Evaporation and respiration
D. Transpiration and photosynthesis
12
177Given are some of the stages of the hydrarch.
A. Marsh-meadow stage
B. Reed-swamp stage
C. Submerged plant stage
D. Phytoplankton stage
E. Free floating plant stage
Select the option that represents the correct sequence of these stages.
( A cdot D rightarrow C rightarrow E rightarrow B rightarrow A )
B ( cdot mathrm{C} rightarrow mathrm{E} rightarrow mathrm{A} rightarrow mathrm{B} rightarrow ) D
( c cdot B rightarrow D rightarrow C rightarrow A rightarrow E )
D. D ( rightarrow E rightarrow C rightarrow B rightarrow A )
12
178Define ecosystem.12
179Keystone species deserve protection
because these
A. Are capable of surviving in harsh environmental conditions
B. Indicates presence of certain minerals in the soil
C. Have become rare due to the over-exploitation
D. Play an important role in supporting other species
12
180Assertion
Secondary succession takes place in
recently denuded area
Reason
It is caused due to baring of an area
A. Both Assertion and Reason are correct and Reason is
the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is
not the correct explanation for Assertion
C. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect
12
181What kind pyramid is represented by
the given figure?
A. pyramid of numbers in a forest ecosystem
B. pyramid of numbers in a parasitic food chain
c. pyramid of biomass in a forest ecosystem
D. It is a wrong pyramid
12
182Identify the wrong pair of statements.
I) During plant succession, some species colonise an area and
populations become more
numerous, whereas populations of other species decline and even disappear.
II) Both hydrarch and xerarch successions lead to mesic conditions.
III) Secondary succession is a slow
process when compared to primary
succession.
IV) In the successive seral stages, there is no change in the diversity of species
of organisms.
( mathbf{A} cdot|,| )
B. ।, ॥
c. ॥॥, IV
D. I, III
12
183What is an ecological pyramid?
Compare the pyramids of energy, biomass and numbers.
12
184The scientists who study ecosystems
are called
A. Ecologists
B. Economists
c. Engineers
D. Environmentalists
12
185A climax community is recognized by
A. Grass,herbs and shrubs
B. Trees
c. High biomass
D. Uniform composition
12
18635. The pollutants which move down
ward with percolating ground
water are called
(1) Leachates (2) Pollutates
(3) Earthites (4) Percolates
12
187What is carbon cycle?12
188Which are the different types of
ecosystems?
12
189Define ecological pyramid12
19045. The plants which grow well, only
in light are known as
(1) Sciophilous
(2) Xerophytes
(3) Heliophytes
(4) Epiphytes
12
191In aqueous environment, the
microscopic organisms are collectively called as
A. Herbivores
B. Carnivores
c. Planktons
D. Fauna and flora
12
192Temperature is considered as the most ecologically relevant environmental factor because it affects of
organisms
A. physiology
B. morphology
c. geographical distribution
D. all of these
12
193Pyramid of energy is always upright, it
represents
A. There is increase in energy of ecosystem.
B. There is decrease in energy due to concentration in successive levels
C. There is decrease in energy due to loss in form of heat in each trophic level
D. There is increase in energy due to gain of heat in each trophic level.
12
194What is mineralisation?12
195The correct sequence of plants in a hydrosere is
( mathbf{A} cdot O a k rightarrow )Lantana( rightarrow V o l v o x rightarrow H y d r i l l a rightarrow P i s t i a rightarrow )
Scirpus
B. ( O a k rightarrow )Lantana( rightarrow )Scirpus( rightarrow )Pistia( rightarrow )Hydrilla( rightarrow )
Volvox
C . ( V ) olvox ( rightarrow ) Hydrilla ( rightarrow ) Pistia ( rightarrow ) Scirpus ( rightarrow )
Lantana( rightarrow )Oak
D. Pistia ( rightarrow ) Volva ( rightarrow ) Scirpus ( rightarrow ) Hydrilla( rightarrow ) Oak ( rightarrow )
Lantana
12
196The consumers are
A. All plants
B. All animals
c. All microbes
D. All living things
12
197In succession, complexities in
structure are
A. Drastically increasing
B. Slowly increasing
c. Not increasing
D. constant
12
198Healthy ecosystems are the base of a wide range of ecosystem services,
Justify.
12
199Term used to describe non-dominant
species that dictates community structure is
A. Pioneer species
B. Keystone species
c. Transitional species
D. Exohenous species
12
200What is ecological succession. Mention
its different steps. Explain Hydrach and Xerarch succession with diagramatic representation.
12
201Primary succession takes much longer
than secondary succession because it
involves:
A. time for development of the soil horizons
B. more time for development of a seed.bank
C. colonization by organisms that are farther away
D. redevelopment of the atmospheric gases
12
202First link in any food system is green plant because
A. Green plants can synthesize food.
B. They can eat everything
c. Fixed at one place
D. None of the above
12
203When two similar species live in the same area, they may evolve to become more different in order to
A. drive the other species to extinction
B. reduce competition
c. use up the other species resources
D. reduce genetic variation
12
204Mid latitude lakes undergo mixing
more than equatorial lakes, select the
correct reason.
A. The midlatitude lakes turn over twice a year
B. Midlatitude lakes develop a thermocline
C. Water is densest at 4
D. All of the above
E. They don’t – equatorial lakes have more mixing
12
205Lichen is pioneer in succession.
A. Hydrosere
B. Lithosere
c. xerosere
D. Both B and C
12
206Identify the plant belonging to the reed swamp stage in hydrosphere
succession
A. Juncus
B. Sagittaria
c. Salix
D. Trapa
12
207We do not clean ponds or lakes, but an
aquarium needs to be cleaned because
A. An aquarium is an artificial and incomplete ecosystem.
B. Pond/lake are natural, self-sustaining and complete ecosystems.
c. Both A and B
D. None of the above
12
208Which one of the following areas is an example of secondary succession if the succession takes place in/on?
A. Abandoned farm land
B. Newly cooled lava
c. Newly created pond
D. Bare rock
12
209Explain the carbon-cycle in nature.12
210Assertion
In a terrestrial ecosystem, detritus food chain is a major conduit for energy flow.
Reason

Solar energy is direct source of energy
supply in detritus food chain.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
c. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect

12
211Will geographical isolation be a major factor in the speciation of self pollinating plant species?Why or why not?12
212Plant succession is a ( ldots ) mess.
A. Definite
c. Unimportant
D. None of the above
12
213Column ( mathbf{A} ) ( – ) Column B
(A) Third trophic level
(p) Ozone
(B) Accumulation of pesticides at higher trophic
(q) CFCs level
(C) Green plants
(r) Herbivore
(D) Flow of energy in an ecosystem
of
(E) Consists of 3 atoms
(t) Decomposers oxygen
nof
(F) Main cause of depletion
(u) Producers ozone layer
(G) Second trophic level
(v) Unidirectional
(H) Break-down of dead
(w) Carnivores organic compounds If
12
214Mycorhhiza is an example of :-
A. Key-stone species
B. Endemic species
c. Critical link species
D. Rare species
12
215An ecosystem does not normally alter because it is in a state of
A. Homeostasis
B. Imbalance
c. Deficient light
D. Deficient components
12
216Write a short note on ecosystem
services.
12
217One of the following areas is an example of secondary succession if succession takes place in / an
A. Abandoned farm land
B. Newly cooled larva
c. New created pond
D. Bare rock
12
218Which of the following is true in an ecosystem?
A. Animals can live without plants
B. Plants can live without animals
C. Animals can survive for long without plants
D. Plants can survive for long without animals
12
219Flora and fauna in lake or pond is
A . Lentic biota
B. Lotic biota
c. Abiotic biota
D. Field layer
12
220Do you think there is any limitation in a detritus food chain?12
221Select the wrong statement.
A. Forest provide variety of products.
B. Forest have great plant diversity.
C. Forest does not conserve soil.
D. Forest conserves water.
12
222Pyramid of numbers in a pond
ecosystem is
A. I rregular
B. Inverted
c. upright
D. Spindle shaped
12
223Tree ecosystem is an example of :-
A. Grazing Food chain
B. Detritus Food Chain
C. Both 1 and 2 above
D. Parasitic Food chain
12
224is the basic unit of ecological hierarchy.
A. Gene
B. Species
c. Individual
D. Animals
12
225Identify the wrong pair of statements
I.During plant succession some species colonise an area and populations becomes more numerous whereas
populations of other species decline and even disappear II.Both hydrarch and xerarch successions lead to mesic conditions
III. Secondary succession is a slow process as compared to primary succession
IV.In successive seral stages there is no change in the diversity of species of organisms
A . ॥ , ॥ ॥
в. ।, ॥
c. ॥॥ , । v
D. 1, Il
12
226Two important groups of detritivores
are
A. Animals and plants
B. Prokaryotes and algae
c. Prokaryotes and fungi
D. Plantae and prokaryotes
12
227In what way are decomposers like
producers?
A. Either one may be the first member of a grazing food chain
B. Both produce oxygen for other forms of life
C. Both require a source of nutrient molecules and energy
D. Both supply organic food for the biosphere
12
228According to the theories of succession,
what will be the result?
A. The lake will get deeper and the trees more numerous
B. The lake will get shallower and the trees will be replaced by grass
c. The lake will dry up
D. The trees will become coniferous types
E. There is no fixed order to the replacement of species
12
229What is ecological succession?12
230The removal of ‘Keystone’ species will effect
A. The producers
B. The consumers
c. The ecosystem
D. The decomposers
12
231What fraction of the assimilated energy
is used in respiration by the herbivores?
A. 10 percent
B. 60 percent
c. 30 percent
D. 80 percent
12
232The pyramid of numbers in grassland
ecosystem will be
A. Upright
B. Inverted
c. I rregular
D. Linear
12
233Plants take nitrogen from the soil by absorption through their roots as This question has multiple correct options
A. Nitrate ions
B. Nitrite ions
c. Ammonium ions
D. All of the above
12
234The second stage of hydrosere is occupied by plants like
A. Typha
B. Salix
c. vallisneria
D. Azolla
12
235Plants of which one of the following groups of genera are pollinated by the same agency?
A. Triticum, cocos, Mangifera
B. Ficus, Kigelia, Casuarina
c. Salvia, Morus, Euphorbia
D. Bombax Butea, Bauhinia
12
236Succession on sand dune is
A. Lithosere
B. Psychrosere
c. Psammosere
D. Halosere
12
237Correct sequence of plants in a
hydrosere is
( mathbf{A} cdot ) Pistia ( rightarrow ) Volvox ( rightarrow ) Scirpus ( rightarrow ) Hydrilla ( rightarrow ) Oak ( rightarrow ) Lantana
B. Oak ( rightarrow ) Lantana ( rightarrow ) Volvox ( rightarrow ) Hydrilla ( rightarrow ) Pistia ( rightarrow ) Scirpus
C. Oak ( rightarrow ) Lantana ( rightarrow ) Scirpus ( rightarrow ) Pistia ( rightarrow ) Hydrilla ( rightarrow ) Volvox
D. Volvox ( rightarrow ) Hydrilla ( rightarrow ) Pistia ( rightarrow ) Scirpus ( rightarrow ) Lantana ( rightarrow ) Oak
12
238Stage of hydrarch are :
(a) Marsh meadow stage
(b) Reed
swamp stage (c) submerged plant
stage
(d) Phytoplankton stage
(e) Submerged free-floating stage.
Identify the correct sequence:
( A cdot d, c, e, b, a )
B. ( c, e, a, b, d )
( c cdot b, d, c, a, e )
D. ( d, e, c, b, a )
E. e, c, b, a, d
12
239Keystone species deserve protection
because these
A. are capable of surviving in harsh environmental conditions
B. indicate presence of certain minerals in the soil
C. have become rare due to overexploitation
D. play an important role in supporting other species.
12
240Mention any two ecological services for the benefit of mankind.12
241Most primary productivity of pond is by
A. Phytoplankton
B. Zooplankton
C. Red algae
D. Floating plants
12
242Name the pioneer and the climax species in a water body. Mention the changes observed in the biomass and the biodiversity of the successive seral communities developing in the
water body
12
243Flg can maintain community structure during food scarcity in tropical deciduous forest these are act as:
A. Exotic species
B. Pioneer species
c. Edge species
D. Key stone species
12
244Minimum components needed for an
ecosystem to survive are
A. Producers and primary consumers
B. Producers and primary carnivores
C. Producers and decomposers
D. Primary consumers and decomposers
12
245All successions proceed to a similar climax community-the mesic Explain.12
246Community dynamics is related to
A. Population growth in an ecosystem
B. Recycling of nutrients in an ecosystem
C. Flow of energy in an ecosystem
D. Ecological succession
12
247Assertion
All pathogens are parasites but all parasites are not pathogens.
Reason
Majority of the parasites confer benefits
to the host.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion,
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
c. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect
12
248According to Robert Constanza, ( 50 % ) of
the total cost for ecosystem services
goes to
A. Recreation
B. Soil formation
c. Nutrient cycling
D. climate regulation
E. Habitat for wildlife
12
249Which of the following statements
differentiates between terrestrial and
aquatic ecosystems?
A. Organisms in terrestrial ecosystems are dependent on oxygen, while those in aquatic ecosystems are not.
B. Nutrients are a limiting factor for populations in aquatic ecosystems but not for terrestrial populations
C. Producers make up the greatest amount of biomass in terrestrial ecosystems, while in aquatic ecosystems they do not.
D. Sunlight is a limiting factor for populations in terrestrial ecosystems but not for populations in aquatic ecosystems.
E. Energy in aquatic ecosystem is transferred from lower to higher trophic levels, but it moves in the opposite direction in aquatic ecosystems
12
250Which one of the following is the definition of ecosystem?
A. A localised association of seven plants and animals.
B. Different communities of plants, animals and microbes, together with their physicochemical environments
c. Different communities of plants and microbes, plus their physicochemical environments.
D. A community of organisms interacting with one another
12
251Which ecological pyramid can never
occur in an inverted form?
A. Pyramid of number
B. Pyramid of biomass
c. Pyramid of energy
D. Pyramid of species richess
12
252Which of the following defines the role of producers in any grazing food chain?
A. Feed the herbivores
B. Feed the carnivores
c. clean the atmosphere
D. Capture solar energy
12
253What is meant by producers in an
ecosystem?
12
254All of the following are components that
make up an ecosystem except
A. Biodiversity
B. Climate
c. Demography
D. Energy flow
E. Nutrient cycling
12
255Keystone species should be protected
as they
A. Are capable of certain minerals in the soil.
B. Indicate presence of certain minerals in the soil.
C. Have become rare due to over-exploitation.
D. Play an important role in supporting other species.
12
256(a) Taking an example of a small pond,
explain how the four components of an
ecosystem function as a unit.
(b) Name the type of food chain that exists in a pond.
12
257Parachute type of mechanism of seed dispersal is found in
A. Pea/ Leguminosae
B. Mustard/ Cruciferae
c. cotton/ Malvaceae
D. Taraxacum/ compositae
12
258Name the term used to describe a
single dominant species that dictates
community structure
A. Pioneer species
B. Transitional species
C. Key stone species
D. Indigenous species
E. Exogenous species
12
259Biotic factors are
A. Chemical factors of soil which affect life.
B. Physical factors of soil which affect life.
C. All living organisms which influence other organisms.
D. Factors of atmosphere which affect life.
12
260A functional aspect of an ecosystem is
A. Producers, consumers and abiotic environment
B. Regulation of populations
C. Light, temperature, oxygen and carbon dioxide
D. Both A and C
12
261A lake ecosystem is
A . Artificial
B. Abiotic
c. Natural
D. Hydrological
12
262In the given food chain, suppose the amount of energy at fourth trophic level is ( 5 mathrm{kJ} ), what will be the energy available at the producer level?Grass Grasshopper- – Frog – Snake – – Hawk
A . 5 kJ
B. 50 kJ
c. ( 500 mathrm{kJ} )
D. 5000 k J
12
263Photosynthesis is absent in
A. Photic layer
B. Aphotic layer
c. Benthic layer
D. Pelagic layer
12
264Which one of the following statements
is correct for secondary succession?
A. It begins on a bare rock
B. It occurs on a deforested site
C. It follows primary succession
D. It is similar to primary succession except that primary succession has a relatively fast pace
12
265When the number of organisms at
successive levels are plotted, they assume the shape of pyramid. This is called as pyramid of
A. Energy
B. Number
c. Biomass
D. Both A and C
12
266Ecosystems may be defined as
A. A species along with environment
B. Plant found in water
C. Plants found on land
D. All plants and animal species along with environment
12
267A group of worms lacking digestive system harbour these bacteria in their
tissues and use them as a source of
organic molecules. In this unique ecosystem, these specific groups of bacteria are playing the role of?
A. Decomposer only
B. Producer only
c. Primary consumer only
D. Secondary consumers only
12
268What is ecosystem? Who coined the
term?
12
269Non-essential components of ecosystem
A. Producer
B. Carbon dioxide
c. secondary produces
D. Transformers
12
270Biological equilibrium is equilibrium amongst
A. Producers and decomposers
B. Producers and consumers
c. Producers, consumers and decomposers
D. consumers and decomposers
12
271According to Lindeman’s 10% law, what amount of energy will be present at the level of primary consumers if the plants produce 4,000 kcal of energy?
A . 40,000 kcal
B. 4,000 kcal
c. 400 kcal
D. 40 kcal
E. 4kcal
12
272A drop of water is an example of :-
A. Micro ecosystem
B. Macro ecosystem
C. Nano ecosystem
D. Both B & C
12
273In a climax community
A. Size of individual is small
B. Food chain and food web is complex
C . Efficiency of energy use is low
D. Ecological niches are few generalised compared to adjoining communities
12
274The trophic efficiency of producers, herbivores and carnivores are
respectively
A. ( 10 %, 20 %, 30 % )
В. ( 20 %, 30 %, 60 % )
c. ( 20 %, 40 %, 80 % )
D. Always ( 10 % )
12
275A pond/lake is
A. A biome
B. A natural ecosystem
C. An artificial ecosystem
D. A community of plants and animals only
12
276The efficiency of any ecosystem is best depicted by pyramid of
A. Energy
B. Number
c. Biomass
D. volume
12
277As the succession proceeds number and types of ( _{text {一一一一一一一一一 }} ) change.
A. Vegetation
B. Animals
c. Vegetation and animals
D. Vegetation, animals and decomposers
12
278Q Type your question
A population study of plants was done
in an abandoned field. Each year for 3
years the vegetation was sampled. The chart indicates the results of the body.
( begin{array}{ll}text { Number } \ text { of } \ text { Year } & text { Plants } \ text { per Acre }end{array} )
Ragweed ( quad ) Timothy
Grass Sandspur begin{tabular}{llll}
1 & 3,800 & 4,900 & 600 \
2 & 1,500 & 2,209 & 1,185 \
hline
end{tabular} 752 2,234
Which of the following are initially most successful in succession?
A. Sandspur and ragweedd
B. Sandspur and timothy grass
c. Ragweed and timothy grass
D. Ragweed and wire grass
E. Sandspur and goldenroo
12
279The term ecological succession was first given by
A. Odum
B. Clements
c. king
D. Hult
12
280In an aquatic environment, microscopic animals and plants are collectively known as
A. Commensals
B. Herbivores
c. Fauna and flora
D. Planktons
12
281Both, hydrarch and xerarch successions
lead to
A. Medium water conditions
B. Xeric conditions
c. Highly dry conditions
D. Excessive wet conditions
12
282What is meant by consumers in an
ecosystem?
12
283Succession is
A. Deforestation to obtain barren lands
B. Series of physical changes involved in colonising a bare area
C. Series of biological changes involved in colonizing an unoccupied area
D. Both B and C
12
284In primary succession on rocks, the pioneer species are usually
A. Algae
B. Fungi
c. Lichens
D. Bryophytes
12
285In the residential area at night, the standard limit of sound intensity is decibel.
A . 55
B. 70
c. 45
D. 40
12
286Serule is
A. Hydrosere
B. Biosere
c. Microbial succession
D. Lithosphere
12
287State the difference between the first
trophic levels of detritus food chain and grazing food chain
12
288An ecosystem which can be easily ruined/damaged but can recover after some time if damaging effect stops. The ecosystem is characterised by having
A. Low and poor stability with low resilience
B. High stability and low resilience
c. Low stability and high resilience
D. High stability and high resilience
12
289Match column I with column II and
select the correct option from the given codes.
Column I Column I I
(i) Vegetation which modifies its
A. Pioneers ( quad ) own environment and thus causing its own replacement
B.
(ii) Replacement of existing Autogenic community by external conditions successic
c.
(iii) Establishment of organisms in Allogenic an area into which they have come by dispersal or migration
D. Ecesis
(iv) Primary colonizers
A. A-(iv), B-(i), C-(ii), D-(iii)
B. A-(i), B-(ii), C-(iii), D-(iv)
c. A-(ii), B-(i), C-(iv), D-(iii)
D. A-(i), B-(iv), C-(iii) D-(ii)
12
290The biotic and abiotic components interacting with each other in a pond form
A. a community
B. a population
c. an ecosystem
D. a biome
12
291An ecosystem is a complex interacting
system of
A . Individuals
B. Population
c. communities and their physical environment
D. Communities and their soil condition
12
292Define a sere.12
293Which one of the following cannot be considered as a decomposer?
A. Fungi
B. Bacteria
c. Hyenas
D. Earthworms
E. Dung beetles
12
294The succession of both hydrarch and xerarch leads to
A. Highly dry conditions
B. Excessive wet conditions
c. Medium water conditions
D. Xeric conditions
12
295What are the components of the
common food chain of a pond
ecosystem?
A. Phytoplanktons, zooplanktons, aquatic plants, small aquatic animals
B. Phytoplanktons, zooplanktons, aquatic plants, small aquatic animals, small fishes, big fishes, birds
C. Phytoplanktons, zooplanktons
D. None of the above
12
296Decomposers converts
A. Organic material into inorganic material
B. Organic matter into carbon dioxide and nutrients
C. Kill the soil microbes
D. All
12
297What are secondary consumers?12
298Which of the following is non-essential
in an ecosystem:-
A. ( C o_{2} )
B. Grass
c. soil
D. Fungi
12
299Why are crop fields known as artificial
ecosystems?
A. Crop fields are man made.
B. Some biotic and abiotic components are manipulated by humans for the production of crop.
C. Both A and B.
D. None of the above
12
300Find the odd one out:
A . Fe
B. 0
( mathrm{c} cdot mathrm{CH}_{4} )
D.
12
301If an ecosystem is composed of only three trophic levels, then how much
energy will be conserved at the III ( ^{r d} )
trophic level?
A . 30%
B. 20%
c. ( 10 % )
D. 1%
12
302Which does not lead to secondary succession?
A. All organisms that existed are lost
B. Where no living organisms ever existed
C. Abandoned crop field
D. Land affected by flood
12
303Name an anthrogenic ecosystem.12
304Assertion
Secondary successive takes place in recently denuded area.
Reason
It is caused due to baring of an area.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
c. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect
12
305Aquatic ecosystem help in
A. Reduce pollution
B. Absorption of nutrients
C . Recycle of nutrients
D. Both A and B
12
306Which of the following method is applicable for pollination in
gymnosperms?
A. Anemophilous
B. Entemophilous
c. Hydrophilous
D. None of the above
12
307A sacred lake is
A. Dal Lake of Kashmir
B. Khecheopalri Lake of Sikkim
C. Suraj Khand Lake of Haryana
D. Chilka Lake of Odisha
12
308Choose the correct set.
begin{tabular}{ll|l|l}
& Column I & & Column \
hline I. & Gross primary productivity & A. & Total ass \
II. & Secondary productivity & B. & Remains and does not situ \
III. & Transducers & C. & Green ple \
IV. & Foodweb & D. & Interlock \
hline
end{tabular}
( mathbf{A} )
।- ( A,|-B,|-C, I V-D )
B. I-B, II-C. III-D, IV-A
C. ( mid-mathrm{C}, ) ।I- ( mathrm{D}, ) III- ( mathrm{A}, mathrm{IV}-mathrm{B} )
D. ( |-A,||-C,|||-B, mid V-D )
12
309Assertion
During an ecological succession, the
number of species increases, the
community biomass increases and the community’s ratio of respiration to photosynthesis also increases.
Reason
At climax community of an ecological
succession, the rate of photosynthesis of a community is almost equal to the rate of respiration.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
c. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect
12
310Pick up the correct option
(a) Primary succession begins in areas where natural communities have been
destroyed
(b) Hydrarch succession takes place in
water
(c) Climax community is the community that is near equilibrium with immediate environment
(d) In newly cooled lava secondary succession occurs
( A cdot ) a and ( b )
B. b and c
c. a and ( d )
D. b only
E. a only
12
311Which of the following is considered as pioneer community in xerarch?
A. Annual herbs
B. Perennial herbs
c. Shrubs
D. Lichens
12
312Most of the plants cultivated in
agriculture are actually belonging to the succession level
A . Early ( 1^{circ} ) succession
B. Late 1 ( ^{circ} ) succession
c. Early ( 2^{circ} ) succession
D. Late ( 2^{circ} ) succession
12
313Pick the correct statement.
A. Home range of members of a species has larger area than that of territory.
B. Many insects mainly honey bees communicate among themselves by secreting pheromones.
C. The last succession in series of biotic succession is called as climax community.
D. Number of individuals of particular species present in a unit area at a given time is known as population size.
12
314Ecosystem is
( A cdot ) Open
B. Closed
C. Both A and B
D. Neither open nor closed
12
315Dominant producers of neritic zone of
sea are the
A. Phytoplankton
B. Zooplankton
c. Microorganisms
D. Diatoms
12
316Ecological factors, which prevent a species from producing at its maximum rate is termed as
A. Survival curve
B. Ecological drift
c. Environmental resistance
D. None of the above
12
317The biotic components of an ecosystem includes
A. Producers, consumers and decomposers
B. Producers and consumers
c. Producers only
D. Consumers only
12
318Keystone species deserve protection
because they
A. Are capable of surviving in harsh environmental conditions.
B. Indicate presence of certain minerals in the soil.
C. Have become rare due to overexploitation.
D. Play an important role in supporting other species.
12
319Which one is more permanent
ecosystem?
A. Forest
B. Mountain
c. Desert
D. Sea
12
320Desert can be converted into a lush
green land by planting
A. Terrestrial plant.
c. Halophytes.
D. Psammophytes.
12
321What do you mean by producers?12
322In a disturbed site in a community recovers and moves again toward the climax state.
A . area effect
B. primary succession
c. distance effect
D. secondary succession
12
323Ecological succession begins with species and end with ( ldots ). …….stage.12
324Cropland ecosystem is a natural
ecosystem
A. True
B. False
12
325Which of the following constitutes the largest ecosystem of the world?
A. Ocean
B. River
c. Forest
D. Grassland
12
326The word ecosystem was coined by……….12
327How do chlorofluorocarbons (CFSs)
enter the atmosphere and how do they affect humans? Explain.
12
328The two components of an ecosystem
are
A. Biotic and abiotic
B. Plants and animals
c. weeds and micro-organism
D. Plants and light
12
329In pyramid of food, the producers
occupy
A. The base
B. Position near the base
c. Apex
D. Position near apex
12
330In comparative study of grassland, arid
pond ecosystems
A. Biotic components are almost similar
B. Abiotic components are almost similar
C. Primary and secondary consumers are similar
D. Biotic and abiotic components are different
12
331Cyberviatic is associated with
A. Flow of energy
B. Cycle of energy
c. Energy released
D. Study of energy
12
332How many statements are incorrect
regarding succession?
(a)During succession climax community is always mesophytes
(b)Future seral community productivity
(c) Increases species diversity, Biomass and humus content.
(d)Gradual replacement from long lived to short lived plant
( A )
B. 2
( c cdot 4 )
D.
12
333Answer in 40 to 80 words:
What is ecological succession?
Distinguish primary succession from secondary succession.
12
334A pond is
A. Biome
B. Natural ecosystem
C. Artificial ecosystem
D. Community of plants and animals
12
335Components of environment are
A. Biotic
B. Abiotic
C. Resources and regulatory factor
D. All of the above
12
336Cyclic succession is
A. Pattern of vegetation change in which a small number of species tend to replace each other over time in the absence of large-scale disturbance
B. Pattern of vegetation change in which large number of species tend to replace each other over time
C. Pattern of vegetation change
D. Pattern of succession change
12
337Who have tried to put price tags on natures life support services?
A. Robert Constanga et al
B. Nile Perch et al
c. Herbert Boyer et a
D. Ram Deo Misra et al
12
338Why bacteria and fungi are called decomposers?12
339Write difference between pioneer community and climax community12
340limiting factor for growth of aquatic organisms is
( A cdot C O_{2} )
в. ( O_{2} )
c. Mineral elements
D. All of the above
12
341Primary succession is development of
communities on
A. Newly exposed habitat.
B. Cleared forest area
c. Freshly harvested crop field.
D. Pond filled after a dry season
12
342Succession in a 6 metre deep pond exhibits a sequence of
A. Submerged Plants – Reeds ( rightarrow ) Herbs ( rightarrow ) Floating Plants
( rightarrow ) Shrubs ( rightarrow ) Trees
B. Floating Plants – Submerged Plants ( rightarrow ) Reeds ( rightarrow ) Herbs
( rightarrow ) Shrubs ( rightarrow ) Trees
c. Shrubsrightarrow Trees ( rightarrow ) submerged Plants ( rightarrow ) Floating Plants
( rightarrow ) Reeds ( rightarrow ) Herbs
D. Submerged Plants ( rightarrow ) Floating Plants ( rightarrow ) Reeds ( rightarrow ) Herbs ( rightarrow ) Shrubs ( rightarrow ) Trees
12
343Ecosystem has
A. Plant and animal
B. Air and ( H_{2} O )
C. Soil and light
D. Biotic and abiotic component
12
344Which one of the following factors is biotic?
A. Photoperiod
B. Carbon dioxide content of the soil
c. Texture and porosity of soil
D. Rainfall
12

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