phylogenetic tree

Diagram showing the evolutionary interrelations of a group of organisms that usually originated from a shared ancestral form. The ancestor is in the tree trunk; organisms that have arisen from it are placed at the ends of tree branches. The distance of one group from the other groups indicates the degree of relationship; that is, closely related groups are located on branches close to one another. Though phylogenetic trees are speculative, they provide a convenient method for studying phylogenetic relationships and evolution. Seealso phylogeny.

Learn more about phylogenetic tree with a free trial on Britannica.com.

A dendrogram (from Greek dendron "tree", -gramma "drawing") is a tree diagram frequently used to illustrate the arrangement of the clusters produced by a clustering algorithm. Dendrograms are often used in computational biology to illustrate the clustering of genes.

For a clustering example, suppose this data is to be clustered using Euclidean distance as the distance metric.

The hierarchical clustering dendrogram would be as such:

Here the top row of nodes represent data, and the remaining nodes represent the clusters to which the data belong, and the arrows represent the distance.

See also

• cladogram