as the father of taxonomy. Linnaeus’ taxonomy grouped living things into two
kingdoms: plants and animals.
By the 1900s, scientists had discovered microorganisms that had characteris-
tics that were dramatically different than those of plants and animals. Therefore,
Linnaeus’ taxonomy needed to be enhanced to encompass microorganisms.
In 1969 Robert H. Whitteker, working at Cornell University, proposed a new
taxonomy that consisted of five kingdoms (see Fig. 9-1). These were monera,
protista, plantae (plants), fungi, and animalia (animals). Moneraare organisms
that lack a nucleus and membrane-bounded organelles, such as bacteria. Protista
are organisms that have either a single cell or no distinct tissues and organs, such
as protozoa. This group includes unicellular eukaryotes and algae. Fungiare
organisms that use absorption to acquire food. These include multicellular fungi
and single-cell yeast. Animalia and plantae include only multicellular organisms.
Scientists widely accepted Whitteker’s taxonomy until 1977 when Carl Woese,
in collaboration with Ralph S. Wolfe at the University of Illinois, proposed a
CHAPTER 9 Classification of Microorganisms^141
Fig. 9-1. Whitteker’s five-kingdom taxonomy.AnimaliaVertebrates AnthropodsPlantaeGreen AlgaeFungiMolds YeastMoneraArchaea Gram Positive Bacteria Gram Negative Bacteria MycoplasmasProtistaRed Algae Amoebas Water Molds