Identify the primary consumers, tertiary consumers, and secondary consumers in the image attached. Which organism has the greatest population in the presented ecosystem? Which organism would normally have the smallest population?

Tropic levels are the answer. Photosynthetic species, such as plants on land and phytoplankton (algae) in the waters, are at the bottom of the food chain, as you surely know. Producers are organisms that obtain their energy from sunlight and inorganic ingredients. Primary consumers are the organisms that devour the producers.

Primary consumers are herbivores feeding on plants (rabbits, mice, grasshopper). Secondary consumers are those that eat the rabbits, grasshoppers, and mice (bird, owl, fox). While the fox is considered a secondary consumer it is also considered a tertiary (3rd) consumer because it will eat a secondary consumer like a bird. There will be more primary consumers and secondary consumers as compared to tertiary consumers within an ecosystem.