( Population ( ( is ( ( ( ( a form ) ( of ( species existence ) ) ) and ) ( ( a unit ) ( of evolution ) ) ) ) . ) )
(ROOT (S (NP (NNP Population)) (VP (VBZ is) (NP (NP (NP (DT a) (NN form)) (PP (IN of) (NP (NN species) (NN existence)))) (CC and) (NP (NP (DT a) (NN unit)) (PP (IN of) (NP (NN evolution)))))) (. .)))
Population is a form of species existence and a unit of evolution.
(ROOT (S (NP (NNP Population)) (VP (VBZ is) (NP (NP (DT the) (NN unit)) (PP (IN of) (NP (NN evolution))))) (. .)))