Amoebozoa

Amoebozoa is a major lineage of eukaryotes that includes many amoeboid protists that move and feed with lobose or tubular pseudopodia. They occur in a wide range of habitats, especially soils, freshwater, and decaying organic matter, and are primarily heterotrophic, ingesting food by phagocytosis. The group comprises free-living unicellular organisms, as well as organisms with complex life histories, including social slime molds and various parasitic or opportunistic species.

Two large subgroups are the Lobosea, which includes naked amoebae such as Amoeba and Chaos, and the Mycetozoa, the slime molds. The Mycetozoa comprises Dictyostelia (cellular slime molds) and Myxogastria (plasmodial slime molds). Other lineages, such as Entamoebida, are also included within Amoebozoa and contribute to its diversity. Members range from simple free-living amoebae to organisms with intricate developmental cycles.

Most Amoebozoa reproduce asexually by binary fission, though some have sexual cycles that are less commonly observed. Dictyostelia are famous for their life cycle in which solitary amoebae aggregate to form a multicellular fruiting body under starvation. Myxogastria form a multinucleate plasmodium that differentiates into sporangia. Many amoebae can form cysts as a response to adverse conditions.

Ecologically, Amoebozoa are important bacterivores and contribute to nutrient cycling in soil and aquatic ecosystems. Several species are medically significant, including Entamoeba histolytica (amebic dysentery), Naegleria fowleri (primary amoebic meningitis), and Acanthamoeba species (keratitis and encephalitis). The group also yields model organisms for basic biology, such as Dictyostelium discoideum, used to study cell motility and development.