Question

How do heterotrophs depend on autotrophs for energy?

Answer 1

Hint: The main function of an ecosystem is energy flow. The two laws of thermodynamics regulate it. Living organisms can use energy in several forms that is radiant and fixed energy. The chemical energy is obtained by the conversion of radiant energy of sunlight.

Complete answer:
The organisms that can fix energy from inorganic sources into organic molecules are called autotrophs. Organisms that cannot make their food from inorganic sources but depend on energy rich organic molecules synthesized by autotrophs for their energy needs are called heterotrophs.
The only source of energy for all the ecosystems of the earth is the sun. Light falling on the plants is trapped by the producers or autotrophs in the presence of chlorophyll and is used in synthesizing the organic food called glucose by the process of photosynthesis. By photosynthesis radiant energy of sunlight is transformed into potential energy of food. A part of this energy is trapped by the producers while the rest of the energy is dissipated. The remaining part of energy which is used in the synthesis of plant biomass is called photosynthate which is then available to the next trophic level in the food chain that is the consumers or heterotrophs. In an ecosystem there is a unidirectional flow of energy.

Note: First law of thermodynamics which states that energy is neither created nor destroyed but transformed from one state to another. The second law of thermodynamics states that energy transformation was degradation or dissipation of energy from a concentrated to a dispersed form due to metabolic functions so only a small part of energy is stored in the biomass.