Question

If you removed the tertiary consumers from a food web, what would be the response of the primary consumers?

Answer 1

With the removal of tertiary consumers from a food web primary consumers would increase in number as there will be no predators to consume these primary consumers. At the same time, with the increase in number of primary consumers, consumption of producers would increase.

Answer 2

          The primary consumers ( herbivores ) feed directly on producers.  The secondary consumers ( carnivores ) feed on the primary consumers and the tertiary consumers feed on the secondary consumers.
          The secondary consumers would increase as the tertiary consumers would not be present. Finally, as a result, a number of the primary consumers would decrease.