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A chordate (/ ˈ k ɔːr d eɪ t / KOR-dayt) is a deuterostomal bilaterian animal belonging to the phylum Chordata (/ k ɔːr ˈ d eɪ t ə / kor-DAY-tə).All chordates possess, at some point during their larval or adult stages, five distinctive physical characteristics (synapomorphies) that distinguish them from other taxa.
This article contains a list of all of the classes and orders that are located in the Phylum Chordata. The subphyla Tunicata and Vertebrata are in the unranked Olfactores clade, while the subphylum Cephalochordata is not. Animals in Olfactores are characterized as having a more advanced olfactory system than animals not in it.
A phylogenetic tree based on rRNA data showing Woese's three-domain system. All smaller branches can be considered kingdoms. Based on RNA studies, Carl Woese thought life could be divided into three large divisions and referred to them as the "three primary kingdom" model or "urkingdom" model. [15]
Below is a phylogenetic tree of the phylum Chordata. Lines show probable evolutionary relationships, including extinct taxa, which are denoted with a dagger, †. Some groups in this tree (lancelets and tunicates) are invertebrates. The positions (relationships) of the lancelet, tunicate, and craniate clades are as reported.
Taxonomic rank is a classification level in biological taxonomy, such as species, genus, family, order, class, phylum, and kingdom.
The main deuterostome phyla are the Ambulacraria and the Chordata. [143] Ambulacraria are exclusively marine and include acorn worms, starfish, sea urchins, and sea cucumbers. [144] The chordates are dominated by the vertebrates (animals with backbones), [145] which consist of fishes, amphibians, reptiles, birds, and mammals. [146] [147] [148]
The Cambrian chordates are an extinct group of animals belonging to the phylum Chordata that lived during the Cambrian, between 538 and 485 million years ago. The first Cambrian chordate known is Pikaia gracilens , a lancelet -like animal from the Burgess Shale in British Columbia , Canada.
A speculatively rooted tree for RNA genes, showing major branches Bacteria, Archaea, and Eukaryota The three-domain tree and the eocyte hypothesis (two-domain tree), 2008. [7] Phylogenetic tree showing the relationship between the eukaryotes and other forms of life, 2006. [8] Eukaryotes are colored red, archaea green, and bacteria blue.