Eucarya

Woese's group subsequently constructed an evolutionary tree in which living organisms are grouped into three domains: Bacteria (eubacteria), Archaea (archaebacteria), and Eucarya (eukaryotic organisms).

Neither bacteria nor eucarya (plants, animals, fungi, and any other organisms with a nucleus in their cells), archaea represent a third branch of life, many scientists contend.

Subsequently, they have been found in many, but not all, members of the archaea, bacteria, and Eucarya [40].

As Case noted, attempted reconciliation of five Kingdoms (Bacteria, Protoctists, Animals, Plants, Fungi) with three Domains (Bacteria, Archaea, Eucarya) resulted in a "compromise" of six kingdoms (Archaebacteria, Eubacteria, Protista, Fungi, Plantae, Animalia)--an outcome that does not fully represent the intent of either the five-kingdom or three-domain system.

Phylogenies based on the small subunit rRNAs (and other molecules) have placed all life in three primary lineages, namely, the Archaea, Bacteria, and Eucarya (8).

Until recently, biologists had divided the so-called tree of life into two main branches, the Bacteria (or Prokaryotes), and the Eucarya (or Eukaryotes).