Yes the impact of removing all the organisms in a trophic level will be different for different trophic levels.

No, the organisms of any trophic level cannot be removed without causing any damage to the ecosystem.

This can be explained with the help of following example of a simple food chain-

Grass, Deer, Lion

• If all the deer population from this food chain is removed, the lions will die out of starvation and the grasses will increase in number and turn the land into forests This is because there will be no deer to feed on, the lions will die; and there will be no deer to eat the grasses, the grasses will keep on growing.

• If we remove all the lions from this food chain, the population of deer will increase in number and eat out all the grasses present, thus turning the land barren.