Question

Represent a forest food chain with the help of the flow chart. Also find out the amount of energy available at the third trophic level, if plants absorb 1000 kilojoules of energy from the sun.

Answer 1

The food chain is the process of eating and being eaten. It is a sequence of living organisms that involve the transfer of food energy across the various trophic levels through a series organism.

Complete answer: A forest chain is defined as a food chain that occurs in the forest. Every food chain starts with the sun. The sun is the main source of all energy on earth. The plant absorbs the energy of the sun and prepares food via the process of photosynthesis. Due to this reason, they are known as producers or autotrophs. They are at the first trophic level of the food chain. The plants are then eaten by the herbivores animals. They form the second level of the food chain. They are also known as the heterotrophs. After this, the herbivores animals are eaten by carnivores. The carnivores can have several trophic levels. Smaller carnivores are usually eaten by bigger carnivores animals. The organisms at the end of the food chain are the top carnivores. After the death of the top carnivores, the decomposer organisms feed on them. They convert the complex biomolecules into the simpler forms.
Ten percent law:
The ten percent law was proposed by Lindeman. This law states that only ten percent of energy is transferred to each trophic level from the previous one. The remaining ninety percent energy is lost in various metabolic processes. If a plant absorbs 1000 kilojoules of energy from the sun then the amount of energy available to the second trophic level can be determined by the ten percent law. Amount of energy available at the second trophic level: $\dfrac{{10}}{{100}}\times 1000 = 100\,kJ$
Therefore, the energy available at the second trophic level will be 100 kJ. Then the energy available at the third trophic level will be,
Amount of energy available at the third trophic level: $\dfrac{{10}}{{100}} \times 100 = 10\,kJ$
Thus, we can conclude that 10 kJ of energy will be available at the third trophic level if plants absorb 1000 kilojoules of energy from the sun.

Note: The interconnected links of various food chains constitute a food web. The food web is a more common occurrence in nature rather than the food chain because all organisms have various alternate options to feed on. Animals might have preferences for their prey but they have several options to prevent them from starving to death.