The Kingdom Protista is a kingdom composed of single-celled
organisms (e.g. protozoa, algae, fungi, slime molds). Aside from being called
as the catchall kingdom, single-celled organisms are also called the left-over kingdom.
This is because when scientists have a hard-time classifying eukaryotic cells
they categorize them under this kingdom.
The Protista kingdom is composed of heterogeneous
species that can perform the same functions as the other kingdoms do but they
lack some membranes and certain functions in their cells to verify their
classifications.
An example of a Protista is the
algae. It first belonged to the plant kingdom but they lack the differentiated
tissues of mosses, ferns, and seed plants that is why they were reclassified by
scientists. Slime molds were also first classified in the fungi kingdom but as
the information on its process accumulated they were group under the Protistas.
