Communities are multi-species assemblages of interacting organisms. The various communities in an ecosystem help transfer energy and cycle chemicals throughout the ecosystem.
Producer communities include multiple species of plants and other photosynthetic organisms that utilize energy from the sun to make chemical energy in the form of sugars. This chemical energy then "flows" to consumer species in the ecosystem.
Primary consumer communities are made up of herbivorous insects and animals which consume primary producers (plants). Primary consumers may include grasshoppers, grazing mammals and birds in terrestrial ecosystems and phytoplankton-feeding shrimp in aquatic ecosystems.
Animals in these communities feed on other consumers (and often producers as well if the animal is omnivorous). Lions, hawks, killer whales and other carnivores are all part of higher-level consumer communities in their respective ecosystems.
Species in these communities derive their energy from dead material produced by the other communities. Decomposers like fungi and scavengers like earthworms and vultures break down organic material and recycle nutrients within the system.