why does the avalable energy decrese from one trophic level to the next?

ICSE Class 8 Answered

why does the avalable energy decrese from one trophic level to the next?

Asked by Chandrashekhar | 17 Aug, 2018, 02:17: PM

Expert Answer

In a food chain, along with food, transfer of energy also occurs from one trophic level to the other.
All living organisms in an ecosystem require energy for carrying out various life processes such as breathing, growth, and movement. This energy supports various activities of the living world.
All the energy used by living organisms is obtained from the Sun. Solar energy enters the living components through the autotrophs or green plants, where it gets converted into chemical energy. However, only 1% of the total energy is actually captured by green plants.
The food energy produced by plants is partially used by them for their growth and development. A major part of it is lost as heat energy.
The plants are then eaten by primary consumers, the herbivores, and the energy stored in plants is transferred to these organisms. A part of the energy is used by herbivores for activities such as digestion, growth, and reproduction. Again, most of the energy is lost to the environment in the form of heat.
When herbivores are consumed by carnivores, a part of the energy is used by the carnivores for their metabolic activities and growth, while most of it is released as heat energy.
The amount of energy gradually declines as one moves up to each higher trophic level because, at each level, energy is lost in the form of heat.
Due to the loss of energy at each step, food chains consist of only three to four trophic levels.

Answered by Sheetal Kolte | 20 Aug, 2018, 12:47: PM