12th Grade > Biology
ECOSYSTEM MCQs
Total Questions : 48
| Page 2 of 5 pages
Answer: Option A. -> Both the A and R are true and R explains A
:
A
Trophic levels in a food chain represents the feeding relationship of organisms in an ecosystem. At each trophic level, organisms will have the action of decomposers as they feed on their dead and decaying parts directly. Mostly decomposers does not occupy a specific level in the food chain as their source of energy can be any organism in the trophic level.
:
A
Trophic levels in a food chain represents the feeding relationship of organisms in an ecosystem. At each trophic level, organisms will have the action of decomposers as they feed on their dead and decaying parts directly. Mostly decomposers does not occupy a specific level in the food chain as their source of energy can be any organism in the trophic level.
Answer: Option A. -> True
:
A
Primary production is defined as the rate of biomass or organic matter produced per unit area over a time period by plants during photosynthesis. It is the producers (plants) which are the prime source of chemical energy in the ecosystem. They convert solar energy into chemical energy and transfer it to the successive level of organisms in a food chain.
:
A
Primary production is defined as the rate of biomass or organic matter produced per unit area over a time period by plants during photosynthesis. It is the producers (plants) which are the prime source of chemical energy in the ecosystem. They convert solar energy into chemical energy and transfer it to the successive level of organisms in a food chain.
Answer: Option D. -> (a) and (b)
:
D
Transfer of food energy from the producers through a series of organisms with repeated eating and being eaten is known as food chain. The food chain consists of producers, primary consumers, secondary consumers, tertiary consumers or top carnivores and decomposers.Energy trapped by the producers are transferred to otherorganismsin thefood chain.Therefore a food chain in an ecosystem represents both feeding relationship and energy flow in an ecosystem. Ecological succession on the other hand,is the gradual process by which ecosystems change and develop over time.
:
D
Transfer of food energy from the producers through a series of organisms with repeated eating and being eaten is known as food chain. The food chain consists of producers, primary consumers, secondary consumers, tertiary consumers or top carnivores and decomposers.Energy trapped by the producers are transferred to otherorganismsin thefood chain.Therefore a food chain in an ecosystem represents both feeding relationship and energy flow in an ecosystem. Ecological succession on the other hand,is the gradual process by which ecosystems change and develop over time.
Question 14. Two ecosystems have almost equal number of animals and are equally rich, that is having similar number of different types of species present in the ecosystem. However, the first ecosystem has 75% water buffaloes. And the second ecosystem has almost equal number of different species. Thus, ecosystem 2 is more diverse than ecosystem 1.
Answer: Option A. -> True
:
A
Species evenness is a parameter that determines how evenly are different species spread across the population of all organisms in the ecosystem. When two ecosystem are equally rich in different types of species, the evenness with which the species are spread across the ecosystem is taken into consideration to determine the diversity. That is,if there are 40 foxes, and 1000 water buffaloes, the community is not very even. But if there are 40 foxes and 42 water buffaloes, the community is quite even.In the above case, we see that the ecosystem 1 has water buffaloes as the major constituent of herbivores, when compared to ecosystem 2 that is quite even, thus ecosystem 2 is more diverse.
:
A
Species evenness is a parameter that determines how evenly are different species spread across the population of all organisms in the ecosystem. When two ecosystem are equally rich in different types of species, the evenness with which the species are spread across the ecosystem is taken into consideration to determine the diversity. That is,if there are 40 foxes, and 1000 water buffaloes, the community is not very even. But if there are 40 foxes and 42 water buffaloes, the community is quite even.In the above case, we see that the ecosystem 1 has water buffaloes as the major constituent of herbivores, when compared to ecosystem 2 that is quite even, thus ecosystem 2 is more diverse.
Answer: Option C. -> Communities and their physical environment
:
C
An ecosystem is a community of living organisms, with the nonliving components of their environment (things like air, water and soil), interacting as a system.
:
C
An ecosystem is a community of living organisms, with the nonliving components of their environment (things like air, water and soil), interacting as a system.
Answer: Option A. -> Amazon
:
A
The diversity of an ecosystem is decided on two factors. Species richness and species evenness. When comparing two ecosystem, both factors are taken into account. However, the species evenness is a deciding factor only when the two ecosystems are equally rich in the number of species. In the case of Amazon forest vs. Western Ghat, the difference in the species richness is far too great to take species evenness into account. Therefore the Amazon forest would be considered to be a much more diverse ecosystem as compared to Western Ghats.
:
A
The diversity of an ecosystem is decided on two factors. Species richness and species evenness. When comparing two ecosystem, both factors are taken into account. However, the species evenness is a deciding factor only when the two ecosystems are equally rich in the number of species. In the case of Amazon forest vs. Western Ghat, the difference in the species richness is far too great to take species evenness into account. Therefore the Amazon forest would be considered to be a much more diverse ecosystem as compared to Western Ghats.
Answer: Option B. -> trees
:
B
The gradual and fairly predictable change in the species composition of a given area is called ecological succession. These changes lead finally to a community that is in near equilibrium with the environment and that is called a climax community. In both primary and secondary sucession the stable community is forest where trees are the most dominat species.
:
B
The gradual and fairly predictable change in the species composition of a given area is called ecological succession. These changes lead finally to a community that is in near equilibrium with the environment and that is called a climax community. In both primary and secondary sucession the stable community is forest where trees are the most dominat species.
Answer: Option D. -> Both B and C
:
D
Anatural ecosystemis anecosystemthat occurs as it would without the influence of human beings. For example terrestrial ecosystems like: forests, grasslands and deserts and aquatic ecosystems like: pond, lake ,estuary, ocean etc. Prairie is a large, mostly flat area of land in North America that has few trees and is covered in grasses.Agricultural farmlands on the other hand are man-made or artificial ecosystems.
:
D
Anatural ecosystemis anecosystemthat occurs as it would without the influence of human beings. For example terrestrial ecosystems like: forests, grasslands and deserts and aquatic ecosystems like: pond, lake ,estuary, ocean etc. Prairie is a large, mostly flat area of land in North America that has few trees and is covered in grasses.Agricultural farmlands on the other hand are man-made or artificial ecosystems.
Answer: Option C. -> A is true and R is false
:
C
Temperature is a major factor that can affect the rate of decomposition. Decomposers are very active in soils having a temperature of more than 25 °C, with good moisture and aeration. Similar conditions prevail in the soil of tropical regions which marks the presence of a thick humus layer in these forests. However, under comparatively low temperatures, rate of decomposition is quite slow even if you have good moisture and aeration, indicating that temperature plays the determining role here.
Decomposition is also an oxygen dependent process. In the presence of oxygen, complex carbon compounds are oxidized to produce carbon dioxide. In this sense, decomposition is essentially equivalent to respiration. If oxygen is absent or in scarce supply, specialized bacteria decompose organic matter anaerobically. Anaerobic decomposition involves more chemical steps and is slower than aerobic. Thus presence of oxygen or aerobic conditions is also a major factor affecting decomposition.
:
C
Temperature is a major factor that can affect the rate of decomposition. Decomposers are very active in soils having a temperature of more than 25 °C, with good moisture and aeration. Similar conditions prevail in the soil of tropical regions which marks the presence of a thick humus layer in these forests. However, under comparatively low temperatures, rate of decomposition is quite slow even if you have good moisture and aeration, indicating that temperature plays the determining role here.
Decomposition is also an oxygen dependent process. In the presence of oxygen, complex carbon compounds are oxidized to produce carbon dioxide. In this sense, decomposition is essentially equivalent to respiration. If oxygen is absent or in scarce supply, specialized bacteria decompose organic matter anaerobically. Anaerobic decomposition involves more chemical steps and is slower than aerobic. Thus presence of oxygen or aerobic conditions is also a major factor affecting decomposition.
Answer: Option A. -> The biomass in each trophic level is lesser than that of the trophic level below in a terrestrial ecosystem.
:
A
Pyramids of biomass can be both inverted as in an aquatic ecosystem or upright as in a forest ecosystem. But, upright pyramids of biomass are usually seen in terrestrial ecosystems. Therefore, it is most appropriate to say that biomass in each trophic level is usually less than the trophic level below in a terrestrial ecosystem.
:
A
Pyramids of biomass can be both inverted as in an aquatic ecosystem or upright as in a forest ecosystem. But, upright pyramids of biomass are usually seen in terrestrial ecosystems. Therefore, it is most appropriate to say that biomass in each trophic level is usually less than the trophic level below in a terrestrial ecosystem.
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