Search results
Results from the WOW.Com Content Network
Archaea (/ ɑːr ˈ k iː ə / ⓘ ar-KEE-ə) is a domain of organisms. Traditionally, Archaea only included its prokaryotic members, but since this has been found to be paraphyletic, as eukaryotes are now known to have evolved from archaea.
The three-domain system adds a level of classification (the domains) "above" the kingdoms present in the previously used five- or six-kingdom systems.This classification system recognizes the fundamental divide between the two prokaryotic groups, insofar as Archaea appear to be more closely related to eukaryotes than they are to other prokaryotes – bacteria-like organisms with no cell nucleus.
The Taxonomic Outline of Bacteria and Archaea is a derived publication indexing taxon names from version two of the manual. [3] It used to be available for free from the Bergey's manual trust website until September 2018. [4] Michigan State University provides an alternative version that indexes NamesforLife records. [5]
Life originated as single-celled prokaryotes and later evolved into the more complex eukaryotes. In contrast to prokaryotic cells, eukaryotic cells are highly organised. Prokaryotes are the bacteria and archaea, while eukaryotes are the other life forms — protists, plants, fungi and animals.
However, this approach is most successful for organisms that had hard body parts, such as shells, bones or teeth. Further, as prokaryotes such as bacteria and archaea share a limited set of common morphologies, their fossils do not provide information on their ancestry. Prokaryotes inhabited the Earth from approximately 3–4 billion years ago.
The tree of life. Two domains of life are Bacteria (top branches) and Archaea (bottom branches, including eukaryotes). The two-domain system is a biological classification by which all organisms in the tree of life are classified into two domains, Bacteria and Archaea.
The Thermoproteota are prokaryotes that have been classified as a phylum of the domain Archaea. [2] [3] [4] Initially, the Thermoproteota were thought to be sulfur-dependent extremophiles but recent studies have identified characteristic Thermoproteota environmental rRNA indicating the organisms may be the most abundant archaea in the marine environment. [5]
Lokiarchaeota is a proposed phylum of the Archaea. [1] The phylum includes all members of the group previously named Deep Sea Archaeal Group, also known as Marine Benthic Group B. Lokiarchaeota is part of the superphylum Asgard containing the phyla: Lokiarchaeota, Thorarchaeota, Odinarchaeota, Heimdallarchaeota, and Helarchaeota. [2]