( ( ( ( Humans , ) and ) ( other mammals ) ) ( ( are extinct ) . ) )
(ROOT (S (NP (NP (NNS Humans)) (, ,) (CC and) (NP (JJ other) (NNS mammals))) (VP (VBP are) (ADJP (JJ extinct))) (. .)))
Humans, and other mammals are extinct.
(ROOT (S (NP (NNP Human) (NNP overpopulation)) (VP (VBZ is) (VP (VP (VBG crowding) (PRT (RP out)) (NP (JJ other) (NNS species))) (CC and) (VP (VBG making) (S (NP (NP (PDT all) (DT the) (JJ other) (NNS causes)) (PP (IN of) (NP (NN extinction)))) (ADJP (RBR worse)))))) (. .)))