Protista

Protista, members of a proposed group of organisms having characteristics of both the plant and the animal kingdoms. The classification usually includes single-celled organisms that have a distinct nucleus and organelles (structures that perform specific functions): protozoans, diatoms, bacteria, and some algae. Some scientists consider multicelled fungi and seaweeds as protista. The classification was proposed by the German zoologist Ernst H. Haeckel (1866).