Paraphyletic group

Definition

A paraphyletic group is a group of organisms that includes an ancestor but not all of its descendants. This contrasts with monophyletic groups, which include all the descendants of a common ancestor.

5 Must Know Facts For Your Next Test

1. Paraphyletic groups are identified based on evolutionary relationships and shared traits.
2. Gymnosperms, like conifers, can form paraphyletic groups when some descendants are excluded.
3. Paraphyletic groups are often recognized because they share certain primitive characteristics not found in more derived groups.
4. These groups are important for understanding evolutionary history and the development of specific traits.
5. In some classifications, paraphyletic groups may be redefined to reflect more accurate evolutionary relationships.

Review Questions

• What distinguishes a paraphyletic group from a monophyletic group?
• Why might gymnosperms be considered a paraphyletic group in certain classifications?
• How do paraphyletic groups help in understanding evolutionary history?

Related terms

Monophyletic Group: A group containing an ancestor and all its descendants.

Polyphyletic Group: A group composed of unrelated organisms descended from more than one ancestor.

Cladistics:

A method in biological classification that categorizes organisms based on shared derived characteristics.