Title: Archaebacteria - Definition, Types, Characteristics and Examples
Headings: Archaebacteria
Archaebacteria
Archaebacteria Definition
Archaebacteria Characteristics
Types of Archaebacteria
Examples of Archaebacteria
Lokiarcheota
Methanobrevibacter Smithii
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Content: Kingdoms,” a way of organizing life forms based on their cell structure, traditionally included Animalia, Planitia, Fungi, Protista (for single-celled eukaryotes), and Monera (which was once considered to hold all forms of prokaryotes). However, genetic and biochemical studies of bacteria soon showed that one class of prokaryotes was very different from “modern” bacteria, and indeed from all other modern life forms. Eventually named “archaebacteria” from “archae” for “ancient,” these unique cells are thought to be modern descendants of a very ancient lineage of bacteria that evolved around sulfur-rich deep sea vents. Sophisticated genetic and biochemical analysis has led to a new “phylogenetic tree of life,” which makes use of the concept of “domains” to describe divisions of life that are bigger and more basic than that of “kingdom.” The most modern version of this system shows all eukaryotes – animals, plants, fungi, and protists – constituting the domain of “Eukaryota,” while the more common and modern branching of bacteria constitutes “Prokarya,” and archaebacteria constitute their own domain altogether – the domain of “Archaea.” The discovery of Archaea and its unique differences is exciting for scientists, because it’s believed that archaebacteria’s unique biochemistry might give us insight into the workings of very ancient life. Some scientists propose that the archaebacteria Thermoplasma may in fact be ancestors of the nuclei of our own eukaryotic cells, which are believed to have developed through the process of endosymbiosis. Another remarkable trait of archaebacteria is their ability to survive in extreme environments, including very salty, very acidic, and very hot surroundings. Archaebacteria have been recorded surviving temperatures as high as 190° Fahrenheit, which is only twenty-two degrees shy of the boiling point of water, and acidities as high as 0.9 pH.
Archaebacteria have even challenged scientist’s ideas about how to define a species, since they practice a lot of horizontal gene transfer – where genes are transferred from one individual to another during their lifetimes – making it difficult to determine how closely different cells are related, or even if archaebacteria cells have the sort of stable combinations of traits that scientists typically use to define a species. The domain of Archaea include both aerobic and anaerobic species, and can be found living in common environments such as soil as well as in extreme environments.