( ( In ( ( ( ( the ( Mesozoic ( era life ) ) ) recovered ) and ) ( ( ( familiar forms ) ( such ( as ( ( mammals and ) birds ) ) ) ) evolved ) ) ) ( , ( ( ( ( ( however ( ( the world ) ( was ( dominated ( by ( the reptiles ) ) ) ) ) ) , ) specifically ) ( ( ( ( the dinosaurs ) , ) ( which ( occupied ( most ( of ( the niches ) ) ) ) ) ) ( now ( occupied ( by ( ( mammals and ) ( some birds ) ) ) ) ) ) ) . ) ) )
(ROOT (S (PP (IN In) (S (S (NP (DT the) (JJ Mesozoic) (NN era) (NN life)) (VP (VBD recovered))) (CC and) (S (NP (NP (JJ familiar) (NNS forms)) (PP (JJ such) (IN as) (NP (NNS mammals) (CC and) (NNS birds)))) (VP (VBD evolved))))) (, ,) (S (ADVP (RB however)) (NP (DT the) (NN world)) (VP (VBD was) (VP (VBN dominated) (PP (IN by) (NP (DT the) (NNS reptiles)))))) (, ,) (ADVP (RB specifically)) (S (NP (NP (DT the) (NNS dinosaurs)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBD occupied) (NP (NP (JJS most)) (PP (IN of) (NP (DT the) (NNS niches)))))))) (ADVP (RB now)) (VP (VBD occupied) (PP (IN by) (NP (NP (NNS mammals)) (CC and) (NP (DT some) (NNS birds)))))) (. .)))
In the Mesozoic era life recovered and familiar forms such as mammals and birds evolved, however the world was dominated by the reptiles, specifically the dinosaurs , which occupied most of the niches now occupied by mammals and some birds.
(ROOT (S (NP (NNS Dinosaurs)) (VP (VBD filled) (NP (DT the) (NNS niches)) (SBAR (IN that) (S (NP (NNS mammals)) (VP (VBP fill) (NP (NN today)) (PP (IN during) (NP (DT the) (JJ mesozoic) (NN era))))))) (. .)))