Lungfish and lizards both have lungs. Can we conclude from this observation that lungfish are the sister group of lizards?
A)No, lungs are an ancestral trait present in all tetrapods and lungfish.
B)No, lungs evolved convergently in lungfish and lizards.
C)Yes, lungs are a synapomorphy that documents the close evolutionary relatedness of lungfish and lizards.
D)No, lungfish do not have two pairs of walking legs and so cannot be closely related to any tetrapod animals.

Question

Quizplus · Accepted Answer

Lungs are an ancestral trait that appeared early in the evolution of vertebrates, and both lungfish and tetrapods (including lizards) inherited this trait from a common ancestor. This does not necessarily mean lungfish are the sister group to lizards, as lungs are not a unique trait that evolved specifically in the lineage leading to lizards.

Lungfish and Lizards Both Have Lungs