( ( Even ( though ( amphibians ( are ( found ( on ( ( every continent ) ( except Antarctica ) ) ) ) ) ) ) ) ( , ( ( their ( continued success ) ) ( ( ( is not ) guaranteed ) . ) ) ) )
(ROOT (S (SBAR (RB Even) (IN though) (S (NP (NNS amphibians)) (VP (VBP are) (VP (VBN found) (PP (IN on) (NP (NP (DT every) (NN continent)) (PP (IN except) (NP (NNP Antarctica))))))))) (, ,) (NP (PRP$ their) (JJ continued) (NN success)) (VP (VBZ is) (RB not) (VP (VBN guaranteed))) (. .)))
Even though amphibians are found on every continent except Antarctica, their continued success is not guaranteed.
(ROOT (S (NP (NNP Antarctica)) (VP (VBZ is) (NP (NP (DT the) (JJ only) (NN continent)) (PP (IN without) (NP (NNS amphibians))))) (. .)))