Multiple outgroups may be used. Parallelism See homoplasy . The central idea of cladistic parsimony analysis is that some trees will fit the character-state data better than other trees. Fit is measured by the number of evolutionary changes implied by the tree. Phenetic Similarity of characters without regard to the distinction between synapomorphy, homoplasy and symplesiomorphy.
Phenetic methods are poor at reconstructing phylogeny.
A polyphyletic group does not include a unique common ancestor, i.e. it has multiple evolutionary origins. A branch-point in a tree with more than two branches. The branches from a node on a cladogram. Note that if either of the daughters undergoes further speciation then the sister to a particular contemporary taxon may actually be a group of contemporary taxa. Speciation The evolutionary splitting of lineages.