Phylogenies

node

point in time when an ancestral group split into two or more descendant groups

branch

a population over time

sister taxa

closely related taxa on adjacent branches arising from same node

outgroup

taxon closely related to particular monophyletic group that does not share same traits

homology

traits that are similar due to shared ancestry

homoplasy

traits that are similar for reasons other than common ancestry and therefore evolved independently

synapomorphy

a shared, derived trait due to common ancestry

monophyletic

an evolutionary group containing an ancestrl population and all its descendants

paraphyletic

a group that includes an ancestral population and some of its descendants

polyphyletic

group whose members’ last common ancester is not a member of the group

parsimony

the idea that the most likely explanation for a phenonmenon is the simpliest