Question

What would happen in an ecosystem without primary consumers?

Answer 1

The ecosystem would consist only of plants and other producers and decomposers.

Explanation:

Primary consumers are the only organisms that are able to "harvest" the energy stored in producers. Without the primary consumers there would be no source of energy for carnivores or secondary consumers so no secondary consumers would exist in that ecosystem. Also there would by definition be no primary consumers.

The producers would be the only organisms in the ecosystem, besides decomposers. The producers would likely over reproduce. removing key nutrients from the soil. The competition between types of producers would likely result in a single type of producer becoming the sole organism in the ecosystem.