Amebas

Amoebae, sometimes spelled Amebas, are unicellular eukaryotic organisms in the group Amoebozoa. They move and feed using pseudopodia, temporary projections of cytoplasm that extend the cell's body. They inhabit a broad range of environments, including soil, freshwater, and marine systems, and some live as parasites in animals.

Morphology is variable; amoebae have flexible, irregular shapes with a clear outer layer (ectoplasm) and a granular inner region (endoplasm). Most species are 10 to 600 micrometers across, though size varies with species and conditions. They lack a rigid cell wall, which allows rapid shape changes.

Movement and feeding: Pseudopodia drive locomotion and enable phagocytosis, by which the cell engulfs bacteria, algae, and detritus. Many free-living amoebae are important in microbial food webs and nutrient cycling. Some form cysts to survive desiccation or starvation.

Reproduction: Most reproduce asexually by binary fission; some lineages display sexual or parasexual processes. Encystment and excystment are common strategies for withstanding harsh environments.

Taxonomy and notable species: Amoebae comprise many genera, including Amoeba, Acanthamoeba, Entamoeba, Naegleria, and the social amoeba Dictyostelium discoideum within Amoebozoa. Entamoeba histolytica is a human parasite causing amebiasis; Naegleria fowleri can cause fatal brain infections; Amoeba proteus is common in laboratories and classrooms.

Ecology and health: They are important decomposers and prey for other microorganisms. While most species are harmless, several can cause disease in humans or animals, highlighting the need for proper hygiene and monitoring in water systems.