That is a picture of an aquatic food web. It starts off with algae, grass, and diatoms (a kind of phytoplankton), the producers in this ecosystem. The energy produced by algae, grass, and diatoms first go to herbivores. Herbivores are organisms that eat producer, they also called Primary Consumers. In this picture, the primary consumers are zoo-plankton, crickets, and snails. Going further on, organisms that eat primary consumers are called secondary consumers. In this picture, the secondary consumers are small fishes, heron, frog, duck, and the black bird. In this picture, heron is both secondary and tertiary consumers. Besides eating snails, heron also eats small fishes. Another tertiary consumer in this picture is snake. Lastly, the quaternary consumer in this picture is the snake-eating eagle. However, it is not over yet. There is one more group in this food web. Yup, it is decomposer. Decomposer is a group that decipher the dead organisms body into components that in turn will help the producers becoming more fertile in nutrition. And that is all about this aquatic food-web.