Question

In a marine ecosystem, phytoplankton perform photosynthesis. Krill eat the phytoplankton, and seals, whales, and sea birds feed on the krill. Finally, great white sharks hunt and eat the seals. Which of these organisms are consumers?

Answer 1

Any organism that eats another organism is a consumer.

Explanation:

Organisms at the base of the food chain, such as plants and phytoplankton that photosynthesize, are producers. Everything else must eat other organisms to survive, so they are consumers.

Other terminology in autotroph and heterotroph. Autotrophs produce their own food (auto = self, troph = eat), while heterotrophs (hetero = other, troph = eat) eat other organisms.

Autotroph = producer
Heterotroph = consumer.