Which of the following could be considered the most recent common ancestor of living tetrapods?
A) a sturdy-finned, shallow-water lobe-fin whose appendages had skeletal supports similar to those of terrestrial vertebrates
B) an armoured, jawed placoderm with two pairs of appendages
C) an early ray-finned fish that developed bony skeletal supports in its paired fins
D) a salamander that had legs supported by a bony skeleton but moved with the side-to-side bending typical of fishes

Question

Quizplus · Accepted Answer

A sturdy-finned, shallow-water lobe-fin whose appendages had skeletal supports similar to those of terrestrial vertebrates is considered the most recent common ancestor of living tetrapods. This is because it had skeletal supports in its appendages that were similar to those of modern tetrapods, which allowed it to make a transition from water to land. The other choices, such as the armoured placoderm and ray-finned fish, did not have the necessary adaptations for life on land. The salamander mentioned in option D is a tetrapod itself, so it cannot be the most recent common ancestor of tetrapods.

Which of the Following Could Be Considered the Most Recent