INTERNATL MICROBIOL (1999) 2:207–216 207 © Springer-Verlag Ibérica 1999 REVIEW ARTICLE Joseph M. Scamardella Not plants or animals: a brief history Office of Information Technologies, University of Massachusetts-Amherst, USA of the origin of Kingdoms Protozoa, Protista and Protoctista Received 30 May 1999 Summary In the wake of Darwin’s evolutionary ideas, mid-nineteenth century Accepted 28 August 1999 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 Correspondence to: Office of Information Technologies, of additional kingdoms (Protozoa, Protista, Protoctista, etc.) to accommodate the A149 LGRT. University of Massachusetts. nature of these organisms as not true plants or animals. Amherst, MA 01003. USA. Tel.: +1-413-5452696. Fax: +1-413-5453203. Key words Protista–Protoctista · Protozoa concept · Monera · John Hogg (1800–1869) · E-mail:
[email protected] Herbert F. Copeland (1902–1968) The greater morphological grouping into kingdoms is, at any one time, a reflection of our understanding of the living world. Protozoa as a class, phylum and kingdom Prior to the 20th century, concepts of organismal