Meet the Protists, Marvelous Misfits in the Tree of Life
As kingdoms go, Protista is a real mess.
The category began with famous 19th-century zoologist Ernst Haeckel, who drew a gnarled tree diagram in 1866 splitting life on Earth into three major branches: Animalia, Plantae, and Protista. Haeckel used the term Protista to describe the microscopic organisms that didn’t look like plants or animals—in ancient Greek, prōtos means “primordial” or “the very first.”
Haeckel pointed out the troublesome task of sorting “all those doubtful organisms of the lowest rank, which display no decided affinities nearer to one side than to the other, or which possess animal and vegetable characters united and mixed.”