( ( ( All ( the members ) ) ( of ( ( one ( particular species ) ) ( in ( a ( give area ) ) ) ) ) ) ( ( are ( called ( a population ) ) ) . ) )
(ROOT (S (NP (NP (PDT All) (DT the) (NNS members)) (PP (IN of) (NP (NP (CD one) (JJ particular) (NNS species)) (PP (IN in) (NP (DT a) (S (VP (VB give))) (NN area)))))) (VP (VBP are) (VP (VBN called) (NP (DT a) (NN population)))) (. .)))
All the members of one particular species in a give area are called a population.
(ROOT (S (NP (NP (PDT All) (DT the) (NNS members)) (PP (IN of) (NP (NP (DT a) (NN species)) (SBAR (WHNP (WDT that)) (S (VP (VBP live) (PP (IN in) (NP (DT the) (JJ same) (NN area))))))))) (VP (VBP form) (NP (DT a) (NN population))) (. .)))
All the members of a species that live in the same area form a population.