( ( Since ( life ( began ( on Earth ) ) ) ) ( , ( ( five ( major ( mass extinctions ) ) ) ( ( have ( ( led ( to ( large ( and ( sudden drops ) ) ) ) ) ( in ( ( the variety ) ( of species ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN Since) (S (NP (NN life)) (VP (VBD began) (PP (IN on) (NP (NNP Earth)))))) (, ,) (NP (CD five) (JJ major) (JJ mass) (NNS extinctions)) (VP (VBP have) (VP (VBN led) (PP (TO to) (NP (JJ large) (CC and) (JJ sudden) (NNS drops))) (PP (IN in) (NP (NP (DT the) (NN variety)) (PP (IN of) (NP (NNS species))))))) (. .)))
Since life began on Earth, five major mass extinctions have led to large and sudden drops in the variety of species.
(ROOT (S (NP (EX There)) (VP (VBP have) (VP (VBN been) (NP (CD five) (JJ major) (JJ massive) (NNS extinctions)) (SBAR (IN since) (S (NP (NN life)) (VP (VBD began) (PP (IN on) (NP (NN earth)))))))) (. .)))