Question 1

Q1: Fill in the blanks. (a) Plants are called as _________ because they fix carbon dioxide. (b) In an ecosystem dominated by trees, the pyramid (of number...

Accepted Answer

(a) Plants are called as autotrophs because they fix carbon dioxide. (b) In an ecosystem dominated by trees, the pyramid (of numbers) is spindle-shaped or inverted type. (c) In aquatic ecosystems, the limiting factor for the productivity is light. (d) Common detritivores in our ecosystem are earthwo...

Question 2

Q10: Define decomposition and describe the processes and products of decomposition.

Accepted Answer

Definition of Decomposition Decomposition is a fundamental ecological process where complex organic matter from dead organisms and their waste products (collectively known as detritus) is broken down into simpler inorganic substances like carbon dioxide, water, and nutrients. This process is primari...

Question 3

Q11: Give an account of energy flow in an ecosystem.

Accepted Answer

Energy flow in an ecosystem describes the path of energy from its initial source through the various living organisms. The flow of energy is a fundamental principle of ecosystem functioning. 1. Source of Energy: Except for deep-sea hydrothermal ecosystems, the sun is the only source of energy for al...

Question 4

Q2: Which one of the following has the largest population in a food chain? (a) Producers (b) Primary consumers (c) Secondary consumers (d) Decomposers

Accepted Answer

The correct answer is (d) Decomposers. Explanation: Decomposers include organisms like bacteria and fungi. Although they are microscopic, their numbers in an ecosystem are vast, far exceeding the number of producers or consumers. They are present in enormous quantities in the soil and at the bottom...

Question 5

Q3: The second trophic level in a lake is (a) Phytoplankton (b) Zooplankton (c) Benthos (d) Fishes

Accepted Answer

The correct answer is (b) Zooplankton. Explanation: In a lake ecosystem, the trophic levels are as follows: - First Trophic Level (Producers): Phytoplankton, which produce their own food through photosynthesis. - Second Trophic Level (Primary Consumers): Organisms that feed on producers. Zooplankton...

Question 6

Q4: Secondary producers are (a) Herbivores (b) Producers (c) Carnivores (d) None of the above

Accepted Answer

The correct answer is (a) Herbivores. Explanation: Primary productivity is the rate of biomass generation by producers (autotrophs). Secondary productivity is the rate of formation of new organic matter by consumers. The term 'secondary producers' refers to the organisms that create this biomass at...

Question 7

Q5: What is the percentage of photosynthetically active radiation (PAR) in the incident solar radiation? (a) $100 \%$ (b) $50 \%$ (c) $1-5 \%$ (d) $2-10 \...

Accepted Answer

The correct answer is (b) $50 \%$. Explanation: According to the chapter, "Of the incident solar radiation less than 50 per cent of it is photosynthetically active radiation (PAR)." Photosynthetically Active Radiation (PAR) refers to the spectral range of solar radiation from 400 to 700 nanometers t...

Question 8

Q6: Distinguish between (a) Grazing food chain and detritus food chain (b) Production and decomposition (c) Upright and inverted pyramid (d) Food chain an...

Accepted Answer

Question 9

Q7: Describe the components of an ecosystem.

Accepted Answer

An ecosystem is a functional unit of nature, and its structure is formed by the interaction of its living and non-living components. These components are broadly categorized into abiotic and biotic components. 1. Abiotic Components: These are the non-living physical and chemical factors of an ecosys...

Question 10

Q8: Define ecological pyramids and describe with examples, pyramids of number and biomass.

Accepted Answer

Ecological Pyramids An ecological pyramid is a graphical representation designed to show the relationship between organisms at different trophic levels in an ecosystem. The shape is pyramidal, with the base representing the producers (first trophic level) and the successive levels towards the apex r...

Question 11

Q9: What is primary productivity? Give brief description of factors that affect primary productivity.

Accepted Answer

Primary Productivity Primary productivity is defined as the rate at which energy is converted by photosynthetic and chemosynthetic autotrophs (producers) to organic substances. In simpler terms, it is the amount of biomass or organic matter produced per unit area over a specific time period by plant...

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