What type of group contains descendants of a common ancestor, excluding the ancestor itself?

The concept of a paraphyletic group is characterized by consisting of a common ancestor and some, but not all, of its descendants. This contrasts with a monophyletic group, which includes an ancestor and all of its descendants, thereby representing a complete branch of the evolutionary tree. A polyphyletic group, on the other hand, is formed based on traits but does not include the most recent common ancestor of the group. The term "clade" typically refers to a monophyletic group, encompassing a common ancestor and all its descendants.

Therefore, the definition provided aligns with the definition of a paraphyletic group, where the focus is on excluding specific descendants while including the common ancestor itself. Understanding these classifications is crucial in phylogenetic studies, as they help clarify relationships and evolution among different species.