Both living (biotic factor) and non-living (abiotic factor) interact with each other and their physical surroundings, constituting an ecosystem that serves as a functional unit of nature. The size of an ecosystem varies from as small as a pond to as large as a sea. There are two categories into which the global ecosystem can be classified – aquatic and terrestrial.
While grasslands, forests and deserts are some examples of terrestrial ecosystems, aquatic ecosystems can be constituted by lakes, ponds, rivers and wetlands. There are man-made ecosystems too, such as aquariums and crop fields.
The chapter covers the following subtopics – Ecosystem -structure and function, productivity, decomposition, energy flow, ecological pyramids, ecological succession, nutrient cycling, and ecosystem services.
Important MCQs on Ecosystem
Explore some important MCQs on this topic below.
1. The 10% energy transfer law of food chain was given by
2. The mass of living material at a trophic level at a particular time is called
a) Standing rate
b) Gross primary productivity
c) Standing crop
d) Net primary productivity
3. Plant decomposers are
a) Animalia and Monera
b) Protista and Animalia
c) Fungi and Plants
d) Monera and Fungi
4. Which of the following is the most stable ecosystem?
5. In a terrestrial ecosystem, such as a forest, the maximum energy is in which trophic level?
6. Which of the following is one of the characteristics of a biological community?
7. If we completely remove the decomposers from an ecosystem, their functioning will be adversely affected because
a) Herbivores will not receive solar energy
b) Energy flow will be blocked
c) The rate of decomposition will be very high
d) Mineral movement will be blocked
8. Vertical distribution of different species occupying different levels in a biotic community is known as
9. Which one of the following animals may occupy more than one trophic level in the same ecosystem at the same time?
10. Which one of the following is a characteristic feature of the cropland ecosystem?
a) Least genetic diversity
b) Absence of soil organisms
c) Ecological succession
d) Absence of weeds
11. Which ecosystem has the maximum biomass?
a) Forest ecosystem
b) Lake ecosystem
c) Pond ecosystem
d) Grassland ecosystem
12. Upper part of sea/aquatic ecosystem contains
c) Plankton and nekton
13. Natural reservoir of phosphorus is
a) Animal bones
14. The breakdown of detritus into smaller particles by earthworms is a process called
15. Most animals that live in deep oceanic waters are
a) Secondary consumers
b) Primary consumers
d) Tertiary consumers
16. In an ecosystem, which one shows a one-way passage?
d) Free energy
17. Both hydrarch and xerarch succession lead to
a) Excessive wet conditions
b) Highly dry conditions
c) Xeric conditions
d) Medium water conditions
18. Which one of the following is a primary consumer in the maize field ecosystem?
19. During ecological succession
a) The establishment of a new biotic community is very fast in its primary phase
b) The gradual and predictable change in species composition occurs in a given area
c) The changes lead to a community that is near equilibrium with the environment, and is called a pioneer community
d) The numbers and types of animals remain constant
20. Which type of ecological pyramid would be obtained with the following data?
Secondary consumer: 120 g
Primary consumer: 60 g
Primary producer: 10 g
a) Upright pyramid of numbers
b) Upright pyramid of biomass
c) Pyramid of energy
d) Inverted pyramid of biomass
Ecosystem Answer Keys
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