Phylogeny

Phylogeny is concerned with the history of evolution of a species or group through examining their lines of descents and relationships through an evolutionary branching diagram known as phylogenetic tree.

The principles of phylogeny

Organisms may be divided or grouped on the basis of differences and similarities. The phylogenetic tree is a visual representation of the evolutionary history for a group of organisms. Each branch point represents the most recent common ancestor of the descendants, and branch length provides a time estimate of divergence.

Two types of phylogenetic trees:

Rooted

Directed tree with a unique node corresponding to the most recent common ancestor ,the edge length of trees may be interpreted as time estimates.

Unrooted

Only illustrate the relatedness of the leaf nodes and do not consider the ancestral roots.

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(Double click to enlarge)1

See also


  1. http://scienceblogs.com/evolgen/2007/03/16/new-terms-in-phylogenetics/