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Botany
Ecosystem
69 questions · Click an option and press Check Answer to reveal the result
1
Stratification is :-
A
Identification and enumeration of plant and animal species of an ecosystem
B
Species composition
C
Vertical distribution of different species occupying different levels
D
Active nature of all the components of the ecosystem as a unit
2
Which of the following statements is true for the given ecological pyramid?
A
Small number of phytoplankton support large number of zooplankton
B
Small biomass of primary producers supports large number of primary consumers in aquatic habitats
C
A large number of herbivores is supported by small number of producers in aquatic habitats
D
A large standing crop of phytoplankton is supported by small standing crop of zooplankton
3
The number of trophic levels in the GFC is restricted as per the:
A
5% law
B
10% law
C
50% law
D
100% law
4
Vertical distribution of different species occupying different levels is called:
A
Stratification
B
Fragmentation
C
Ecozones
D
Zonation
5
Which of the following are the 4 basic components of functioning of an ecosystem?
A
Productivity, Stratification, Respiration, Nutrient cycling
B
Producers, Consumers, Decomposers, Energy flow
C
Productivity, Decomposition, Energy flow, Nutrient cycling
D
Producers, Consumers, Decomposers, Trophic levels
6
The entire sequence of communities that successively change in a given area are called:
A
Sere
B
Pioneer
C
Climax
D
Niche
7
In a terrestrial ecosystem, a much larger fraction of energy flows through the:
A
GFC
B
DFC
C
Parasitic food chain
D
None of these
8
The average price tag for ecosystem services is estimated at:
A
US $18 trillion
B
US $33 trillion
C
US $50 trillion
D
US $5 trillion
9
Which of the following is a major producer in a terrestrial ecosystem?
A
Phytoplankton
B
Herbaceous and woody plants
C
Algae
D
Zooplankton
10
Assertion (A) : The decomposition rate is slower when detritus contains substances like lignin and chitin.
Reason (R) : Lignin and chitin are highly resistant to microbial action and undergo very slow decomposition. Which of the following is correct?
A
Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
B
Both Assertion and Reason are true, but Reason is not the correct explanation of Assertion.
C
Assertion is true, but Reason is false.
D
Assertion is false, but Reason is true.
11
Decomposition is faster when:
A
Detritus is rich in lignin and chitin
B
Environment is cold and anaerobic
C
Detritus is rich in nitrogen and water-soluble substances
D
Soil is very acidic
12
The diagram below represents a crucial step in decomposition of detritus being performed by an organism. Choose the correct option related to it. 
A
The step shows the breakdown of detritus into smaller particles by detritivores, process known as catabolism.
B
This step is coupled with release of inorganic nutrients above the soil.
C
This is the first step of decomposition that occurs on or within the top layers of soil.
D
The raw material for this process is living plants and animals.
13
Which of the following ecosystem has the highest contribution to global net primary productivity?
A
Tropical deciduous forest
B
Tropical rainforest
C
Desert
D
Temperate grassland
14
Which one of the following statements is incorrect regarding ecosystem?
A
Net Primary Productivity (NPP) is the available biomass for herbivores and decomposers.
B
Decomposition is slower when detritus is rich in nitrogen and water-soluble substances.
C
In aquatic ecosystems, the grazing food chain is the major conduit for energy flow.
D
Pyramid of energy can never be inverted.
15
The annual net primary productivity of the whole biosphere is approximately:
A
170 billion tons
B
55 billion tons
C
115 billion tons
D
200 billion tons
16
Identify true (T) or false (F) statements and select the correct option.
a. Tropical rainforest and sugarcane field are the most productive ecosystems.
b. Secondary productivity is the rate of formation of new organic matter by consumers.
c. Humus is colourless and partly decomposed organic matter.
A
a-T, b-T, c-F
B
a-T, b-T, c-T
C
a-F, b-T, c-F
D
a-T, b-F, c-F
17
What is the annual net primary productivity of the oceans?
A
170 billion tons
B
55 billion tons
C
115 billion tons
D
100 billion tons
18
According to the 10% law, if producers have 1000 J of energy, how much is available to secondary consumers?
A
100 J
B
10 J
C
1 J
D
0.1 J
19
Plants capture only ______ of the PAR.
A
50%
B
2-10%
C
0.1%
D
25%
20
Which of the following is NEVER inverted?
A
Pyramid of number
B
Pyramid of biomass
C
Pyramid of energy
D
All of these
21
Reservoir for the sedimentary cycle is:
A
Atmosphere
B
Ocean
C
Earth’s crust
D
Living organisms
22
Succession in water bodies is called:
A
Xerarch
B
Hydrarch
C
Mesarch
D
Halosere
23
The process where water-soluble inorganic nutrients go down into the soil horizon and get precipitated as unavailable salts is:
A
Fragmentation
B
Leaching
C
Catabolism
D
Mineralization
24
The products of ecosystem processes are named as:
A
Ecosystem functions
B
Ecosystem services
C
Ecosystem goods
D
Ecosystem products
25
The major reservoir of phosphorus is:
A
Atmosphere
B
Rock minerals
C
Ocean water
D
Soil solution
26
The process of breaking down complex organic matter into inorganic substances like CO2, water, and nutrients is:
A
Humification
B
Mineralization
C
Decomposition
D
Fragmentation
27
Given below are two statements:-
Statement I : Gause's competitive exclusion principle states that two closely related species competing for different resources cannot co-exist indefinitely.
Statement II : According to Gause's principle, during competition, the inferior one will be eliminated. This may be true if resources are limiting.
In the light of the above statements, choose the correct answer from the options given below:
A
Statement I is true but Statement II is false.
B
Statement I is false but Statement II is true.
C
Both Statement I and Statement II are true.
D
Both Statement I and Statement II are false.
28
Specific place of the organisms in the food chain is called:
A
Niche
B
Trophic level
C
Stratum
D
Biome
29
What is the percentage of Photosynthetically Active Radiation (PAR) in the incident solar radiation?
A
100%
B
Less than 50%
C
2-10%
D
1-5%
30
Succession that starts in an area where no living organisms ever existed is:
A
Primary succession
B
Secondary succession
C
Tertiary succession
D
Autogenic succession
31
Detritus Food Chain (DFC) begins with:
A
Grass
B
Phytoplankton
C
Dead organic matter
D
Herbivores
32
Which of the following is a characteristic of secondary succession?
A
It is slower than primary succession
B
It begins on bare rock
C
It starts in areas where natural biotic communities were destroyed
D
It takes thousands of years to reach climax
33
Which one of the following processes during decomposition is correctly described?
A
Leaching – Water soluble inorganic nutrients rise to the top layers of soil
B
Fragmentation – Carried out by organisms such as earthworms
C
Humification – Leads to the accumulation of a dark coloured substance humus which resists microbial action
D
Catabolism – Last step in the decomposition uses anaerobic condition
34
Who tried to put price tags on nature’s life-support services?
A
Paul Ehrlich
B
Robert Costanza
C
Ernest Mayr
D
Von Humboldt
35
The correct sequence of components of a forest ecosystem from top to bottom strata is;
A
Herbs and Grasses → Shrubs → Trees
B
Herbs and Grasses → Trees → Shrubs
C
Shrubs → Herbs and Grasses → Trees
D
Trees → Shrubs → Herbs and Grasses
36
Which of the following is a sedimentary cycle?
A
Carbon cycle
B
Nitrogen cycle
C
Phosphorus cycle
D
Oxygen cycle
37
Natural reservoir of phosphorus is:
A
Animal bones
B
Sea water
C
Rock
D
Fossil fuels
38
A major difference between carbon and phosphorus cycles is:
A
Carbon cycle has no respiratory release
B
Phosphorus cycle has a significant gaseous exchange
C
Atmospheric inputs of phosphorus through rainfall are much smaller than carbon
D
Plants do not require phosphorus
39
Consider the following sentences:
I. Anaerobic bacteria and fungi form mesh-like structures.
II. Bacteria and fungi form a mesh-like structure in an air-contained sludge digester tank.
III. Mixture of gases
IV. Primary sludge before biological treatment
Select the right option for flocs-
A
I and II
B
I and III
C
Only II
D
Only III
40
The cost of climate regulation and habitat for wildlife is estimated at:
A
6% each
B
50%
C
10% each
D
20%
41
Secondary productivity is the rate of formation of new organic matter by:
A
Producers
B
Parasites
C
Consumers
D
Decomposers
42
An inverted pyramid of biomass is typically found in:
A
Grassland ecosystem
B
Forest ecosystem
C
Sea/Pond ecosystem
D
Desert ecosystem
43
Out of the total cost of various ecosystem services, soil formation accounts for:
A
6%
B
10%
C
50%
D
16%
44
What are flocs?
A
Masses of anaerobic bacteria
B
Masses of aerobic fungi and anaerobic bacteria
C
Masses of anaerobic bacteria and fungi
D
Masses of aerobic bacteria associated with fungal filaments
45
Unidirectional flow of energy occurs from:
A
Sun → Producers → Consumers
B
Consumers → Producers → Sun
C
Decomposers → Producers → Sun
D
Sun → Consumers → Producers
46
The amount of nutrients present in the soil at any given time is:
A
Standing crop
B
Standing state
C
Humus
D
Detritus
47
Below diagram represents age pyramids of human population. In which a, b & c represent triangular, Bell shaped and Urn shaped age pyramids of the following statement is true
A
The number of prereproductive individuals is more than reproductive individuals & post reproductive individuals in Bell shaped age pyramids
B
The number of post reproductive individuals is equal to number of reproductive individuals in Triangular age pyramid
C
The number of reproductive individuals is more than post reproductive individuals and pre reproductive individuals in urn shaped age pyramid
D
The number of prereproductive individuals & reproductive individuals are equal in triangular shaped curve
48
Identify the organism at the Fourth Trophic Level (TC):
A
Grass
B
Grasshopper
C
Frog
D
Man or Lion
49
Which of the following is NOT a way carbon returns to the atmosphere?
A
Respiration
B
Decomposition
C
Photosynthesis
D
Burning of fossil fuels
50
Match the following Column-I Column-II
| Column I | Column II |
|---|---|
APlants | iLion |
BDecomposer | iiPhytoplanktons |
CHerbivores | iiiCow |
DTop carnivores | ivFungi |
A
A-iv, B-i, C-ii, D-iii
B
A-iv, B-iii, C-i, D-ii
C
A-iii, B-i, C-iv, D-ii
D
A-ii, B-iv, C-iii, D-i
51
The raw material for decomposition is:
A
Soil
B
Humus
C
Detritus
D
Minerals
52
An example of a gaseous nutrient cycle is:
A
Phosphorus cycle
B
Calcium cycle
C
Nitrogen cycle
D
Magnesium cycle
53
Which of the following is the correct sequence of decomposition?
A
Fragmentation → Leaching → Catabolism → Humification → Mineralization
B
Leaching → Fragmentation → Catabolism → Humification → Mineralization
C
Catabolism → Leaching → Fragmentation → Humification → Mineralization
D
Fragmentation → Catabolism → Leaching → Mineralization → Humification
54
The climax community in both Hydrarch and Xerarch succession is:
A
Desert
B
Grassland
C
Forest
D
Marsh
55
Bacterial and fungal enzymes degrade detritus into simpler inorganic substances. This is called:
A
Leaching
B
Catabolism
C
Humification
D
Fragmentation
56
Which of the following relations is correct regarding GPP and NPP?
A
NPP = R - GPP
B
NPP = GPP - R
C
GPP = NPP - R
D
GPP = R - NPP
57
Identify the incorrect statement.
A
The species continue to live through millions of years unless threatened by natural or anthropogenic extinction.
B
Sexual reproduction enhances the survival advantage of species.
C
Reproduction becomes a vital process without which species cannot survive for long.
D
Sexual reproduction leads to formation of clones of parents.
58
Which one of the following has the largest population in a food chain in most ecosystems?
A
Producers
B
Primary consumers
C
Secondary consumers
D
Primary carnivores
59
Which of the following is NOT true about a pond ecosystem?
A
A pond is a shallow, simple, self-sustainable water body
B
Pond does not exhibit all basic components of an ecosystem
C
Autotrophic components include Phytoplankton and marginal plants
D
Fungi, bacteria and flagellates act as Decomposers
60
Pyramid of biomass and energy in ocean for a typical grazing food chain would be
A
Upright always
B
Inverted & Upright respectively
C
Inverted & spindle shaped respectively
D
Spindle shaped & Upright respectively
61
The mass of living material in a trophic level at a particular time is called:
A
Standing state
B
Standing crop
C
Biomass
D
Productivity
62
Sequence of communities in Hydrarch succession is:
A
Phytoplankton → Submerged → Free floating → Reed swamp → Marsh-meadow → Scrub → Trees
B
Trees → Scrub → Marsh-meadow → Reed swamp → Free floating → Submerged → Phytoplankton
C
Phytoplankton → Free floating → Submerged → Marsh-meadow → Reed swamp → Scrub → Trees
D
Lichen → Moss → Herb → Shrub → Trees
63
The pioneer species in Xerarch succession are:
A
Phytoplankton
B
Lichens
C
Mosses
D
Herbs
64
Identify the correct statement regarding decomposition:
A
It is largely an oxygen-requiring process
B
Warm and moist environment inhibits decomposition
C
Humus is highly susceptible to microbial action
D
Mineralization leads to the accumulation of humus
65
Functional unit of nature is:
A
Habitat
B
Ecosystem
C
Community
D
Biome
66
In the phosphorus cycle, phosphate is released from rocks by:
A
Respiration
B
Weathering
C
Volcanic activity
D
Photosynthesis
67
Several processes occur simultaneously during decomposition of detritus. choose incorrect option for catabolism and fragmentation. 
A
A and B
B
C only
C
B and C
D
A only
68
Which ecosystem has maximum biomass?
A
Grassland ecosystem
B
Pond ecosystem
C
Lake ecosystem
D
Forest ecosystem
69
The rate of biomass production is called:
A
Decomposition
B
Stratification
C
Productivity
D
Humification
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