title: Not plants or animals: a brief history of the origin of Kingdoms Protozoa, Protista and Protoctista.
abstract: In the wake of Darwin's evolutionary ideas, mid-nineteenth century naturalists realized the shortcomings of the long established two-kingdom system of organismal classification. Placement in a natural scheme of Protozoa, Protophyta, Phytozoa and Bacteria, microorganisms that exhibited plant-like and animal-like characteristics but obviously differed in organization from larger plants and animals, challenged traditional classification. The attempts of naturalists to classify these organisms outside the constraints of the plant and animal kingdoms led to concepts of additional kingdoms (Protozoa, Protista, Protoctista, etc.) to accommodate the nature of these organisms as not true plants or animals.
authors.affiliation: Office of Information Technologies, University of Massachusetts-Amherst 01003, USA. jms@oit.umass.edu
authors.forename: J M
authors.initials: JM
authors.lastname: Scamardella
mesh_terms: D000818:Animals; D001419:Bacteria / Q000145:classification; D005075:Biological Evolution; D056890:Eukaryota / Q000145:classification*; D005658:Fungi / Q000145:classification; D049672:History, 19th Century; D049673:History, 20th Century; D007448:Invertebrates / Q000145:classification; D008829:Microbiology / Q000266:history*; D008954:Models, Biological; D010802:Phylogeny; D010944:Plants / Q000145:classification; D011387:Prokaryotic Cells / Q000145:classification; D009626:Terminology as Topic