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Species of the infraorder Cetacea A phylogenetic tree showing the relationships among cetacean families. [1]The evolution of cetaceans is thought to have begun in the Indian subcontinent from even-toed ungulates (Artiodactyla) 50 million years ago (mya) and to have proceeded over a period of at least 15 million years. [2]
Representing the earliest cetacean radiation, they include the initial amphibious stages in cetacean evolution, thus are the ancestors of both modern cetacean suborders, Mysticeti and Odontoceti. [2] This initial diversification occurred in the shallow waters that separated India and Asia 53 to 45 mya , resulting in some 30 species adapted to a ...
The following is a list of currently existing (or, in the jargon of taxonomy) 'extant' species of the infraorder cetacea (for extinct cetacean species, see the list of extinct cetaceans). The list is organized taxonomically into parvorders, superfamilies when applicable, families, subfamilies when applicable, genus, and then species.
Cetacea (/ s ɪ ˈ t eɪ ʃ ə /; from Latin cetus 'whale', from Ancient Greek κῆτος 'huge fish, sea monster') [3] is an infraorder of aquatic mammals belonging to the order Artiodactyla that includes whales, dolphins and porpoises.
[6] HGT is thus a potential confounding factor in inferring phylogenetic trees from the sequence of one gene. For example, if two distantly related bacteria have exchanged a gene, a phylogenetic tree including those species will show them to be closely related even though most other genes have diverged substantially. For this reason it is ...
A phylogenetic tree, phylogeny or evolutionary tree is a graphical representation which shows the evolutionary history between a set of species or taxa during a specific time. [ 1 ] [ 2 ] In other words, it is a branching diagram or a tree showing the evolutionary relationships among various biological species or other entities based upon ...
The list of extinct cetaceans features the extinct genera and species of the order Cetacea. The cetaceans (whales, dolphins and porpoises) are descendants of land-living mammals, the even-toed ungulates. The earliest cetaceans were still hoofed mammals.
Because a plesiomorphic character inherited from a common ancestor can appear anywhere in a phylogenetic tree, its presence does not reveal anything about the relationships within the tree. [4] Thus grouping species requires distinguishing ancestral from derived character states. [5]