Branch

A branch is a line connecting either two internal nodes to each other or an external node A node in a phylogenetic tree represents a taxon, the external or terminal nodes represent the extant taxa and the internal nodes represent the ancestral taxa. to an internal node A node in a phylogenetic tree represents a taxon, the external or terminal nodes represent the extant taxa and the internal nodes represent the ancestral taxa. in a phylogenetic tree.  The length of a branch denotes the genetic distance (e.g., number of substitutions per unit time) between the two taxa A taxon is the individual unit whose evolutionary relationship is being investigated. Depending on the study, “taxa” may refer to species, populations, individuals, or sequences within an individual. it connects.