Question

A group consisting of a common ancestor and some, but not all, of its descendants is known as a ________ group.

1) polytomy

2) polyphyletic

3) praphyletic

4) monohyletic

Answer 1

The group that consists of a common ancestor and some, but not all, of its descendants is known as a paraphyletic group. This is in contrast to a monophyletic group which includes all descendants of a common ancestor.

Step-by-step explanation:

A group consisting of a common ancestor and some, but not all, of its descendants is known as a paraphyletic group. Therefore, the correct answer is 3) paraphyletic.

The concept of a paraphyletic group contrasts with other types of groups in phylogenetics such as monophyletic groups (also known as clades), which consist of a common ancestor and all of its descendants, and polyphyletic groups, which are composed of unrelated organisms that do not share an immediate common ancestor.

Understanding these different groupings is crucial for studying evolutionary relationships as depicted in a phylogenetic tree, which is a diagram that reflects the evolutionary relationships among organisms or groups of organisms, revealing their phylogeny, or evolutionary history and relationship.