( ( Selection ( imposed ( by competitors ) ) ) ( ( may ( lead ( to ( ( ( character displacement ) , ) ( where ( ( populations ( of ( two ( ( closely related ) species ) ) ) ) ( ( ( are different ) ( -LRB- ( ( ( morphologically or ) behaviorally ) -RRB- ) ) ) ( where ( ( the ( two species ) ) ( ( ( ( occur together ) , ) but ) ( are ( indistinguishable ( where ( they ( occur alone ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NNP Selection)) (VP (VBN imposed) (PP (IN by) (NP (NNS competitors))))) (VP (MD may) (VP (VB lead) (PP (TO to) (NP (NP (NN character) (NN displacement)) (, ,) (SBAR (WHADVP (WRB where)) (S (NP (NP (NNS populations)) (PP (IN of) (NP (CD two) (ADJP (RB closely) (JJ related)) (NNS species)))) (VP (VBP are) (ADJP (JJ different)) (PRN (-LRB- -LRB-) (NP (JJ morphologically) (CC or) (JJ behaviorally)) (-RRB- -RRB-)) (SBAR (WHADVP (WRB where)) (S (NP (DT the) (CD two) (NNS species)) (VP (VP (VBP occur) (ADVP (RB together))) (, ,) (CC but) (VP (VBP are) (ADJP (JJ indistinguishable) (SBAR (WHADVP (WRB where)) (S (NP (PRP they)) (VP (VBP occur) (ADVP (RB alone))))))))))))))))) (. .)))
Selection imposed by competitors may lead to character displacement , where populations of two closely related species are different (morphologically or behaviorally) where the two species occur together, but are indistinguishable where they occur alone.
(ROOT (S (NP (NNP Character) (NNP displacement)) (VP (VBZ is) (NP (NP (DT the) (NN concept)) (PP (IN by) (SBAR (WHNP (WHNP (WDT which) (CD two) (NNS species)) (PP (IN within) (NP (DT the) (JJ same) (NN area)))) (S (VP (TO to) (VP (VB coexist) (PP (IN by) (S (VP (VBG adapting) (PP (IN by) (S (VP (VBG developing) (NP (JJ different) (NNS specializations))))))))))))))) (. .)))