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 armored, 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
Biology · High School · Thu Feb 04 2021
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The most recent common ancestor of living tetrapods could be considered "a) a sturdy-finned, shallow-water lobe-fin whose appendages had skeletal supports similar to those of terrestrial vertebrates." This description fits well with what paleontologists and evolutionary biologists understand about the transition from life in water to life on land. Lobe-finned fishes, particularly those from the group known as Sarcopterygii, had bones in their fins that resemble the limb bones of terrestrial vertebrates, and their fin structure is seen as a precursor to the limbs of tetrapods.