Ch Ecosystem last 10 yrs Flashcards
- Which ecosystem has the maximum biomass? (2017-Delhi)
a. Forest ecosystem
b. Grassland ecosystem
c. Pond ecosystem
d. Lake ecosystem
a. Forest ecosystem
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- The term ecosystem was coined by: (2016 - I)
a. E.P. Odum
b. A.G. Tansley
c. E. Haeckel
d. E. Warming
b. A.G. Tansley
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- Which one of the following is a characteristic feature of cropland ecosystem? (2016 - I)
a. Absence of soil organisms
b. Least genetic diversity
c. Absence of weeds
d. Ecological succession
b. Least genetic diversity
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- Vertical distribution of different species occupying different levels in a biotic community is known as: (2015)
a. Zonation
b. Pyramid
c. Divergence
d. Stratification
Grade 12 / Chapter 12 Ecosystem / page 206
d. Stratification
NCERT
Vertical distribution of different species occupying different levels is called stratification.
For example, trees occupy top vertical strata or layer of a forest, shrubs the second and herbs and grasses occupy the bottom layers
REMEMBER
Vertical distribution of different species occupying different levels = Stratification
- An association of individuals of different species living in the same habitual and having functional interactions is: (2015 Re)
a. Biotic community
b. Ecosystem
c. Population
d. Ecological niche
a. Biotic community
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- In the equation GPP-R = NPP. (2021)
R represents:
a. Retaradation factor
b. Environment factor
c. Respiration losses
d. Radiant energy
Grade 12 / Chapter 12 Ecosystem / page 207
C. Respiration losses
NCERT
Gross primary productivity minus respiration losses (R),
is the net primary productivity (NPP).
GPP – R = NPP
REMEMBER
GPP = Gross primary productivity
R = Respiration losses
NPP = Net primary productivity
- In relation to gross primary productivity and net primary productivity of an ecosystem, which one of the following statements is correct? (2020)
a. Gross primary productivity is always more than net primary productivity.
b. Gross primary productivity and net primary productivity are one and same.
c. There is no relationship between Gross primary productivity and net primary productivity
d. Gross primary productivity is always less than net primary productivity.
Grade 12 / Chapter 12 Ecosystem / page 207
a. Gross primary productivity is always more than net primary productivity.
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But remember this from NCERT
REMEMBER
Gross primary productivity minus respiration losses (R),
is the net primary productivity (NPP).
GPP – R = NPP (207)
- In an ecosystem, the rate of production of organic matter during photosynthesis is termed as: (2015)
a. Secondary productivity
b. Net productivity
c. Net primary productivity
d. Gross primary productivity
Grade 12 / Chapter 12 Ecosystem / page 207
d. Gross primary productivity
NCERT
Gross primary productivity of an ecosystem is the rate of production of organic matter during photosynthesis
REMEMBER
rate of production of organic matter during photosynthesis =
Gross primary productivity
- Secondary productivity is rate of formation of new organic matter by: (2013)
a. Decomposer
b. Producer
c. Parasite
d. Consumer
Grade 12 / Chapter 12 Ecosystem / page 207
d. Consumer
NCERT
Secondary productivity is defined as the rate of formation of new organic matter by consumers
REMEMBER
rate of formation of new organic matter by consumers =
Secondary productivity
- Given below are two statements: (2022)
Statement I: Decomposition is a process in which the detritus is degraded into simpler substances by microbes.
Statement II: Decomposition is faster if the detritus is rich in lignin and chitin
In the light of the above statements, choose the correct answer from the options given below.
a. Statement I is incorrect but Statement II is correct
b. Both Statement I and Statement II are correct
c. Both statement I and statement II are incorrect
d. Statement I is correct but Statement II is incorrect
Grade 12 / Chapter 12 Ecosystem / page 207 - 208
d. Statement I is correct but Statement II is incorrect
NCERT
STATEMENT I
Similarly, decomposers break down complex organic matter into inorganic substances like carbon dioxide, water and nutrients and the process is called decomposition.
Dead plant remains such as leaves, bark, flowers and dead remains of animals, including fecal matter, constitute detritus, which is the raw material for decomposition. (207)
Decomposition is largely an oxygen-requiring process. The rate of
decomposition is controlled by chemical composition of detritus and
climatic factors.
Statement II
In a particular climatic condition, decomposition rate
is slower if detritus is rich in lignin and chitin, and
quicker, if detritus is rich in nitrogen and water-soluble substances like sugars. (208)
REMEMBER
decomposition rate / slower = detritus is rich in lignin and chitin
decomposition rate / quicker = detritus is rich in nitrogen and
water soluble substances (sugars)
Decomposition is a process in which the detritus is degraded into simpler substances by microbes.
- Detritivores breakdown detritus into smaller particles. This process is called. (2022)
a. Decomposition
b. Catabolism
c. Fragmentation
d. Humification
Grade 12 / Chapter 12 Ecosystem / page 207
c. Fragmentation
NCERT
Detritivores (e.g., earthworm) break down detritus into smaller particles. This process is called fragmentation.
REMEMBER
Detritivores (e.g., earthworm) break down detritus into smaller particles = fragmentation.
- The rate of decomposition is faster in the ecosystem due to following factors EXCEPT:
(2020-Covid)
a. Warm and moist environment
b. Presence of aerobic soil microbes
c. Detritus richer in lignin and chitin
d. Detritus rich in sugars
Grade 12 / Chapter 12 Ecosystem / page 208
c. Detritus richer in lignin and chitin
NCERT
decomposition rate is slower if detritus is rich in lignin and chitin
CHECK THE OTHER OPTIONS OUT
REMEMBER
decomposition rate / slower = detritus is rich in lignin and chitin
decomposition rate / quicker = detritus is rich in nitrogen and
water soluble substances (sugars)
- Which one of the following processes during decomposition is correctly described? (2013)
a. Leaching: Water soluble inorganic nutrients rise to the top layers of soil
b. Fragmentation: Carried out by organisms such as earthworm
c. Humification: Leads to the accumulation of a dark colored substance humus which undergoes microbial action at a very fast rate
d. Catabolism: Last step in the decomposition under fully anaerobic condition
Grade 12 / Chapter 12 Ecosystem / page 207
b. Fragmentation: Carried out by organisms such as earthworm
NCERT
Detritivores (e.g., earthworm) break down detritus into smaller particles. This process is called fragmentation
REMEMBER
Detritivores (e.g., earthworm) break down detritus into smaller particles = fragmentation.
- Which of the following statements is not correct ? (2021)
a. Pyramid of biomass in sea is generally upright.
b. Pyramid of energy is always upright.
c. Pyramid of numbers in a grassland ecosystem is upright.
d. Pyramid of biomass in sea is generally inverted.
Grade 12 / Chapter 12 Ecosystem / page 213
a. Pyramid of biomass in sea is generally upright.
NCERT
The pyramid of biomass in sea is generally inverted because the
biomass of fishes far exceeds that of phytoplankton. Isn’t that a paradox? How would you explain this?
REMEMBER
Pyramid of biomass in sea = generally inverted
- Match the trophic levels with their correct species examples in grassland ecosystem. (2020)
Column-I Column-II
1. Fourth trophic level (i) Crow
- Second trophic level (ii) Vulture
- First trophic level (iii) Rabbit
- Third trophic level (iv) Grass(1) (2) (3) (4)
a. (iii) (ii) (i) (iv)
b. (iv) (iii) (ii) (i)
c. (i) (ii) (iii) (iv)
d. (ii) (iii) (iv) (i)
Grade 12 / Chapter 12 Ecosystem / page 211
(1) (2) (3) (4)
d. (ii) (iii) (iv) (i)
- Fourth trophic level - (ii) Vulture
- Second trophic level - (iii) Rabbit
- First trophic level - (iv) Grass
- Third trophic level - (i) Crow
NCERT
Add the image
REMEMBER
1. First tropic level = grass
2. Second tropic level = rabbit
3. Third tropic level = crow
4. Fourth tropic level = vulture
- Which of the following statements is incorrect? (2020-Covid)
a. Energy content gradually increases from first to fourth trophic level
b. Number of individuals decreases from first trophic level to fourth trophic level
c. Energy content gradually decreases from first to fourth trophic level
d. Biomass decreases from first to fourth trophic level
a. Energy content gradually increases from first to fourth trophic level
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- Which of the following ecological pyramids is generally inverted? (2019)
a. Pyramid of numbers in grassland
b. Pyramid of energy
c. Pyramid of biomass in a forest
d. Pyramid of biomass in a sea
Grade 12 / Chapter 12 Ecosystem / page 213
d. Pyramid of biomass in a sea
NCERT
The pyramid of biomass in sea is generally inverted because the
biomass of fishes far exceeds that of phytoplankton. Isn’t that a paradox? How would you explain this?
REMEMBER
Pyramid of biomass in a sea = generally inverted
- What type of ecological pyramid would obtained with the following data? (2018)
Secondary consumer : 120 g
Primary consumer : 60 g
Primary producer : 10 g
a. Inverted pyramid of biomass
b. Pyramid of energy
c. Upright pyramid of numbers
d. Upright pyramid of biomass
a. Inverted pyramid of biomass
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- The primary producers of the deep-sea hydrothermal vent ecosystem are: (2016 - II)
a. Blue-green algae
b. Coral reefs
c. Green algae
d. Chemosynthetic bacteria
d. Chemosynthetic bacteria
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- The mass of living material at a tropic level at a particular time is called: (2015)
a. Net primary productivity
b. Standing crop
c. Gross primary productivity
d. Standing state
Grade 12 / Chapter 12 Ecosystem / page 211
b. Standing crop
NCERT
Each trophic level has a certain mass of living material at a particular
time called as the standing crop
REMEMBER
Each trophic level has a certain mass of living material at a particular
time = standing crop
- Most animals that live in deep oceanic waters are: (2015)
a. Secondary consumers
b. Tertiary consumers
c. Detritivores
d. Primary consumers
c. Detritivores
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- If 20 J of energy is trapped at producer level, then how much energy will be available to peacock as food in the following chain? (2014)
Plant → Mice → Snake → Peacock
a. 0.0002 J
b. 0.02 J
c. 0.002 J
d. 0.2 J
b. 0.02 J
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- Presence of plants arranged into well defined vertical layers depending on their height can be seen best in: [RC] (2017-Delhi)
a. Tropical Savannah
b. Tropical Rain Forest
c. Grassland
d. Temperate Forest
b. Tropical Rain Forest
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- Which of the following would appear as the pioneer organisms on bare rocks? [RC] (2016 - I)
a. Lichens
b. Liverworts
c. Mosses
d. Green algae
a. Lichens
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- Secondary succession takes place on/in: [RC] (2015)
a. Newly created pond
b. Newly cooled lava
c. Bare rock
d. Degraded forest
d. Degraded forest
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- During ecological succession: [RC] (2015 Re)
a. The establishment of a new biotic community is very fast in its primary phase.
b. The numbers and types of animals remain constant.
c. The changes lead to a community that is in near equilibrium with the environment and is called pioneer community
d. The gradual and predictable change in species composition occurs in a given area
d. The gradual and predictable change in species composition occurs in a given area
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- The second stage of hydrosere is occupied by plants like: [RC] (2013)
a. Azolla
b. Typha
c. Salix
d. Vallisneria
d. Vallisneria
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- Which one of the following will accelerate phosphorus cycle? [RC] (2022)
a. Rain fall and storms
b. Burning of fossil fuels
c. Volcanic activity
d. Weathering of rocks
d. Weathering of rocks
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- The amount of nutrients, such as carbon, nitrogen, phosphorus and calcium present in the soil at any given time is referred as: [RC] (2021)
a. Climax community
b. Standing state
c. Standing crop
d. Climax
b. Standing state
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- Which of the following statements is incorrect regarding the phosphorus cycle? [RC] (2020-Covid)
a. Phosphorus solubilizing bacteria facilitate the release of phosphorus from organic remains
b. There is appreciable respiratory release of phosphorus into atmosphere
c. It is sedimentary cycle
d. Phosphates are the major form of phosphorus reservoir
b. There is appreciable respiratory release of phosphorus into atmosphere
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- In which of the following both pairs have correct combination? [RC] (2015 Re)
a. Gaseous nutrient cycle Carbon and sulphur
Sedimentary nutrient cycle Nitrogen and Phosphorus
b. Gaseous nutrient cycle Nitrogen and sulphur
Sedimentary nutrient cycle Carbon and Phosphorus
c. Gaseous nutrient cycle Sulphur and Phosphorus
Sedimentary nutrient cycle Carbon and Nitrogen
d. Gaseous nutrient cycle Carbon and Nitrogen
Sedimentary nutrient cycle Sulphur and Phosphorus
d. Gaseous nutrient cycle Carbon and Nitrogen
Sedimentary nutrient cycle Sulphur and Phosphorus
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- Given below is a simplified model of phosphorus cycling in a terrestrial ecosystem with four blanks (A-D). Identify the blanks. [RC] (2014)
insert the image
A B C D
a. Producers Litter fall Rock minerals Detritus
b. Rock minerals Detritus Litter fall Producers
c. Litter fall Producers Rock minerals Detritus
d. Detritus Rock minerals Producer Litter fall
A B C D
d. Detritus Rock minerals Producer Litter fall
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- Natural reservoir of phosphorus is: [RC] (2013)
a. Fossils
b. Sea water
c. Animal bones
d. Rock
d. Rock
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- Match the following and select the correct option: [RC] (2014)
A. Earthworm i. Pioneer species
B. Succession ii. Detritivores
C. Ecosystem service iii. Natality
D. Population growth iv Pollination
A B C D
a. ii i iv iii
b. i ii iii iv
c. iv i iii ii
d. iii ii iv i
ABCD
a. ii i iv iii
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