Amoeba are unicellular eukaryotes with no cell wall. They reproduce using binary fission and move by the use of pseudopodia. Pseudopodia are false feet that extend out, and then the rest of the body follows. Amoeba are found in ponds, rivers and on the surface of leaves and plants.
Amoeba, also known as ameba, belong to the phylum Sarcodina and the kingdom Protista. They were previously classified in the animal kingdom. Amoebas are very small and contain a single nucleus. They constantly change their body shape due to ameboid movement. Most amoebas are harmless, but some are pathogenic and cause serious diseases.
Amoebas engulf their prey with their pseudopodia, forming food vacuoles. The pseudopodia may be rounded at the tip, pointed, branched and fused together or slightly rigid and pointed. The amoeba secrete digestive enzymes that are poured into the food vacuoles, which digest the particles. Amoebas can distinguish food from other materials. Under good conditions, amoebas split using binary fission to produce two daughter amoebas. When split artificially, the portion containing the nucleus forms a new cell membrane and becomes a whole animal, while the other portion eventually dies. If there is not food or water, amoebas secrete a protective covering and wait until conditions become right for them to actively divide.