( ( Within ( a ( given species ) ) ) ( , ( ( ( not ( all members ) ) ( of ( the population ) ) ) ( ( respond ( to ( the ( same ( dose identically ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN Within) (NP (DT a) (VBN given) (NN species))) (, ,) (NP (NP (RB not) (DT all) (NNS members)) (PP (IN of) (NP (DT the) (NN population)))) (VP (VBP respond) (PP (TO to) (NP (DT the) (JJ same) (NN dose) (NN identically)))) (. .)))
Within a given species, not all members of the population respond to the same dose identically.
(ROOT (S (NP (NP (DT All) (NNS members)) (PP (IN of) (NP (DT a) (NN species) (NN living)))) (ADVP (RB together)) (VP (VB form) (NP (DT a) (PRN (-LRB- -LRB-) (NP (NN n)) (-RRB- -RRB-)) (NN population))) (. .)))