( ( A population ) ( ( is ( ( a group ) ( of ( organisms ( of ( ( the ( same species ) ) ( within ( a ( defined area ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT A) (NN population)) (VP (VBZ is) (NP (NP (DT a) (NN group)) (PP (IN of) (NP (NP (NNS organisms)) (PP (IN of) (NP (NP (DT the) (JJ same) (NN species)) (PP (IN within) (NP (DT a) (JJ defined) (NN area))))))))) (. .)))
A population is a group of organisms of the same species within a defined area.
(ROOT (S (NP (PRP You)) (VP (VBP call) (NP (NP (DT a) (NN group)) (PP (IN of) (NP (NP (NNS organisms)) (PP (IN of) (NP (DT the) (JJ same) (NN species)))))) (SBAR (IN that) (S (VP (VBP live) (PP (IN in) (NP (DT the) (JJ same) (NN area)))) (NP (DT a) (-LRB- -LRB-) (NN n) (-RRB- -RRB-) (NN population))))) (. .)))