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Chapter Analysis
Intermediate10 pages • EnglishQuick Summary
The chapter on Ecosystems describes ecosystems as functional units of nature comprising abiotic and biotic components. It covers critical concepts such as productivity, decomposition, energy flow, and nutrient cycling, highlighting how these processes interact to sustain ecosystems. Specific examples, like ponds, demonstrate these interactions. The chapter details ecological pyramids and discusses the roles of producers, consumers, and decomposers within ecosystems.
Key Topics
- •Structure and function of ecosystems
- •Productivity and its types
- •Decomposition processes
- •Energy flow and trophic levels
- •Nutrient cycling
- •Ecological pyramids
- •Role of decomposers
Learning Objectives
- ✓Understand the structure and function of ecosystems
- ✓Describe the processes of productivity and decomposition
- ✓Explain the flow of energy through different trophic levels
- ✓Illustrate nutrient cycling with examples
- ✓Discuss ecological pyramids and their significance
- ✓Recognize the essential roles of producers, consumers, and decomposers
Questions in Chapter
Fill in the blanks. (a) Plants are called as_________because they fix carbon dioxide. (b) In an ecosystem dominated by trees, the pyramid (of numbers) is_________type. (c) In aquatic ecosystems, the limiting factor for the productivity is_________. (d) Common detritivores in our ecosystem are_________. (e) The major reservoir of carbon on earth is_________.
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Which one of the following has the largest population in a food chain? (a) Producers (b) Primary consumers (c) Secondary consumers (d) Decomposers
Answer: Producers
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The second trophic level in a lake is (a) Phytoplankton (b) Zooplankton (c) Benthos (d) Fishes
Answer: Zooplankton
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Secondary producers are (a) Herbivores (b) Producers (c) Carnivores (d) None of the above
Answer: None of the above
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What is the percentage of photosynthetically active radiation (PAR) in the incident solar radiation? (a) 100% (b) 50 % (c) 1-5% (d) 2-10%
Answer: 2-10%
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Distinguish between (a) Grazing food chain and detritus food chain (b) Production and decomposition (c) Upright and inverted pyramid (d) Food chain and Food web (e) Litter and detritus (f) Primary and secondary productivity
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Describe the components of an ecosystem.
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Define ecological pyramids and describe with examples, pyramids of number and biomass.
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What is primary productivity? Give brief description of factors that affect primary productivity.
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Define decomposition and describe the processes and products of decomposition.
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Give an account of energy flow in an ecosystem.
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Additional Practice Questions
Explain the role of decomposers in an ecosystem.
mediumAnswer: Decomposers break down dead organic matter into simpler inorganic substances. This process is critical for recycling nutrients in the ecosystem, returning essential elements to the soil and water, which can be reused by autotrophs.
How does energy flow through an ecosystem?
easyAnswer: Energy flows through an ecosystem in a unidirectional manner, starting from the sun to producers and then to consumers. Ultimately, it is lost as heat. Each trophic level passes only 10% of energy to the next, following the 10% energy law.
Discuss the importance of ecological pyramids in understanding ecosystem dynamics.
mediumAnswer: Ecological pyramids visually represent the number, biomass, or energy at each trophic level of an ecosystem. They help in understanding the efficiency of energy transfer and the structure of ecosystems, including relationships between different organisms.
What factors affect the rate of decomposition in an ecosystem?
mediumAnswer: The decomposition rate is influenced by the chemical composition of the detritus, temperature, and moisture. Detritus rich in lignin decomposes slowly, while nitrogen-rich detritus decomposes faster. Warmer, moist environments speed up decomposition.
How would the absence of decomposers affect an ecosystem?
hardAnswer: Without decomposers, dead organic matter would accumulate, leading to a shortage of essential nutrients. This would disrupt nutrient cycling, hampering plant growth and impacting the entire food web.
Illustrate the differences between a grazing food chain and a detritus food chain.
mediumAnswer: The grazing food chain starts with producers consumed by herbivores, while the detritus food chain begins with decomposers that feed on dead organic matter. Both chains interconnect, forming complex food webs.
Describe the concept of nutrient cycling with examples.
mediumAnswer: Nutrient cycling involves the movement and exchange of organic and inorganic matter back into the production of living matter. Key cycles include the carbon and nitrogen cycles, crucial for maintaining ecosystem productivity.
Why is the pyramid of energy always upright?
easyAnswer: The pyramid of energy is always upright because energy is lost as heat at each trophic level during transfer, leading to lesser energy as you move up the trophic levels.
What is the significance of stratification in ecosystems?
hardAnswer: Stratification refers to the vertical distribution of different species in an ecosystem, allowing for niche specialization and efficient utilization of resources, ultimately supporting biodiversity.
Differentiate between primary and secondary productivity.
mediumAnswer: Primary productivity refers to the rate at which energy is converted by producers into organic substances, while secondary productivity pertains to the formation of biomass by consumers.