This chapter gives an overview of community ecology patterns and processes, mainly focusing on the Species Richness and Diversity, Abundance, Trophic structure, Niche differentiation, and Ecological interactions. The chapter deals with the organization of trophic structures, including the food chain and the food web. The chapter deals with niche differentiation, by which competing species use the environment differently in a way that facilitates their coexistence. This chapter explores species interactions such as competition, mutualism, parasitism, and predation. It also focuses on the keystone species, describing their impact on the community. Additionally, the chapter highlights the ecological succession from primary to secondary succession