ArchaeaEubacteriaEukaryota Evolved from the earliest cells The “modern” prokaryotes Consists of all eukaryotes (cells with a nucleus Inhabit only very extreme environments Over 10,000 species Consists of the 4 kingdoms: Protista Fungi Plantae Animalia Only a few hundred species exist Differ structurally, biochemically, and physiologically from Archaea
live in harsh environments and may represent the first cells to have evolved. Sewage treatment plants, thermal vents, etc. Archaea
some of which cause human diseases, are present in almost all habitats on earth. Many bacteria are important environmentally and commercially. Live in the intestines of animals Eubacteria,
Example: Streptococcus mutans forms biofilms on teeth, which cause dental decay.