( ( The population ) ( ( is ( ( the unit ) ( of ( natural ( ( selection and ) evolution ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN population)) (VP (VBZ is) (NP (NP (DT the) (NN unit)) (PP (IN of) (NP (JJ natural) (NN selection) (CC and) (NN evolution))))) (. .)))
The population is the unit of natural selection  and evolution.
(ROOT (S (NP (NNP Population)) (VP (VBZ is) (NP (NP (DT the) (NN unit)) (PP (IN of) (NP (NN evolution))))) (. .)))