Clade

A clade (from Ancient Greek κλάδος, klados, "branch") or monophylum (see monophyletic) is a group consisting of an ancestor and all its descendants, a single "branch" on the "tree of life". The ancestor may be an individual, a breeding pair, a population or even a species (extinct or extant). Many familiar groups, the rodents and the insects for example, are clades; others, like the lizards and the monkeys, are not.