Question

Identify the taxa that constitute a paraphyletic group in the given phylogenetic tree.

• A. A, B, C
• B. D, E, F
• C. B, C, D
• D. C, D, E

Hint:

Paraphyletic = ancestor + some descendants (excluding at least one).

Answer 1

The Correct Option is B

Step 1: Recall group definitions.
- Monophyletic group: Includes a common ancestor and all descendants.
- Paraphyletic group: Includes a common ancestor but only some descendants (not all).
- Polyphyletic group: Includes members without their most recent common ancestor.
Step 2: Analyze tree.
- A, B, C: These form a monophyletic group (all descendants included).
- D, E, F: Share a common ancestor, but G (a descendant of the same ancestor) is excluded → Paraphyletic.
- B, C, D: Members from two different clades → polyphyletic.
- C, D, E: Not valid clade grouping.
Step 3: Conclusion.
The paraphyletic group is D, E, F. Final Answer: \[ \boxed{\text{D, E, F form a paraphyletic group.}} \]