( ( The fins ) ( ( ( ( evolved ( into ( ( the legs ) ( of ( the ( first ( tetrapod ( land vertebrates ) ) ) ) ) ) ) ) , ) amphibians ) . ) )
(ROOT (S (NP (DT The) (NNS fins)) (VP (VBD evolved) (PP (IN into) (NP (NP (DT the) (NNS legs)) (PP (IN of) (NP (DT the) (JJ first) (JJ tetrapod) (NN land) (NNS vertebrates))))) (, ,) (ADVP (RB amphibians))) (. .)))
The fins evolved into the legs of the first tetrapod land vertebrates, amphibians.
(ROOT (S (NP (NNS Caecillians)) (VP (VBD evolved) (PP (IN from) (NP (JJ tetrapod) (NNS ancestors)))) (. .)))