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Question
Assertion: Pyramids of energy are always upright
Reason: Only 10% of the energy from one trophic level is transferred to the next trophic level in a food chain
Assertion: Pyramids of energy are always upright
Reason: Only 10% of the energy from one trophic level is transferred to the next trophic level in a food chain
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Solution
The correct option is A Both assertion and reason are true and the reason is the correct explanation for the assertion
Energy flow in the ecosystem is the flow of energy from the sun through the successive trophic levels.
The trophic levels in an ecosystem denote the different levels in a food chain, based on the food source of an organism. As an organism of one trophic level feeds on another organism of a lower trophic level, the energy flows through the ecosystem.
Sunlight is the ultimate source of energy for all ecosystems. It is trapped, utilised and introduced in the food chain by photosynthetic organisms like green plants and algae to prepare food. These organisms form the first trophic level known as producers.
Consumers are dependent on the producers for food. The primary consumers (herbivores) that directly feed on the producers form the second trophic level.
The third trophic level is composed of the secondary consumers who feed on the primary consumers.
Top or apex carnivores like lions, tigers, etc are the tertiary consumers which feed on the secondary consumers and form the fourth trophic level.
The pyramid of energy is a graphical representation of the energy present in the various trophic levels. Producers form the base of the pyramid and the top carnivores form the apex of the pyramid.
The pyramid of energy is always upright because the energy is maximum at the producer level (first trophic level) and gradually decreases as we move towards the apex of the pyramid.
This is because the organism in each trophic level utilises the energy for various metabolic activities and energy is lost in the form of heat. Hence, only 10% of the energy is transferred from one trophic level to the next.
Thus, both assertion and reason are true and the reason is the correct explanation for the assertion.
Energy flow in the ecosystem is the flow of energy from the sun through the successive trophic levels.
The trophic levels in an ecosystem denote the different levels in a food chain, based on the food source of an organism. As an organism of one trophic level feeds on another organism of a lower trophic level, the energy flows through the ecosystem.
Sunlight is the ultimate source of energy for all ecosystems. It is trapped, utilised and introduced in the food chain by photosynthetic organisms like green plants and algae to prepare food. These organisms form the first trophic level known as producers.
Consumers are dependent on the producers for food. The primary consumers (herbivores) that directly feed on the producers form the second trophic level.
The third trophic level is composed of the secondary consumers who feed on the primary consumers.
Top or apex carnivores like lions, tigers, etc are the tertiary consumers which feed on the secondary consumers and form the fourth trophic level.
The pyramid of energy is a graphical representation of the energy present in the various trophic levels. Producers form the base of the pyramid and the top carnivores form the apex of the pyramid.
The pyramid of energy is always upright because the energy is maximum at the producer level (first trophic level) and gradually decreases as we move towards the apex of the pyramid.
This is because the organism in each trophic level utilises the energy for various metabolic activities and energy is lost in the form of heat. Hence, only 10% of the energy is transferred from one trophic level to the next.
Thus, both assertion and reason are true and the reason is the correct explanation for the assertion.
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