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The Open Tree of Life is an online phylogenetic tree of life – a collaborative effort, funded by the National Science Foundation. [2] [3] The first draft, including 2.3 million species, was released in September 2015. [4] The Interactive graph allows the user to zoom in to taxonomic classifications, phylogenetic trees, and information about a ...
The idea of a tree of life arose from ancient notions of a ladder-like progression from lower into higher forms of life (such as in the Great Chain of Being).Early representations of "branching" phylogenetic trees include a "paleontological chart" showing the geological relationships among plants and animals in the book Elementary Geology, by Edward Hitchcock (first edition: 1840).
For example, in a full tree of life, the entire clade of animals can be collapsed to a single branch of the tree. However, this is merely a limitation of rendering space. In theory, a true and complete tree for all living organisms or for any DNA sequence could be generated. [4] Nevertheless, phylogenies can sometimes appear in a non-treelike form.
Least squares distance tree construction aims to find the tree (topology and branch lengths) with minimal S. This is a non-trivial problem. It involves searching the discrete space of unrooted binary tree topologies whose size is exponential in the number of leaves. For n leaves there are 1 • 3 • 5 • ... • (2n-3) different topologies.
Phylogenetics is the taxonomical classification of organisms based on how closely they are related in terms of evolutionary differences. The main article for this category is Phylogenetics . Wikimedia Commons has media related to Phylogenetics .
It is a group of techniques within the larger fields of phylogenetics and genomics. Phylogenomics draws information by comparing entire genomes, or at least large portions of genomes. [3] Phylogenetics compares and analyzes the sequences of single genes, or a small number of genes, as well as many other types of data.
The science that tries to reconstruct phylogenetic trees and thus discover clades is called phylogenetics or cladistics, the latter term coined by Ernst Mayr (1965), derived from "clade". The results of phylogenetic/cladistic analyses are tree-shaped diagrams called cladograms; they, and all their branches, are phylogenetic hypotheses. [12]