What will happen if we kill all the organisms in one trophic level?

Explanation

Killing of all organisms in one trophic level will stop the transfer of food energy to next trophic level. Therefore, organism in the next trophic level will die while the individuals of the lower trophic level will exhibit enormous growth in their population. It will break down the food chain which will create imbalance in the ecosystem. Both the conditions will result in ecological upset. For example, if we remove deer (second trophic level) from a food chain, the population of carnivores will deplete while the primary producer, that is, grass and plants will show high growth.