( ( The ( term ( ecological niche ) ) ) ( ( refers ( to ( how ( ( an organism ) ( functions ( in ( an ecosystem ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN term) (JJ ecological) (NN niche)) (VP (VBZ refers) (PP (TO to) (SBAR (WHADVP (WRB how)) (S (NP (DT an) (NN organism)) (VP (VBZ functions) (PP (IN in) (NP (DT an) (NN ecosystem)))))))) (. .)))
The term ecological niche refers to how an organism functions in an ecosystem.
(ROOT (S (NP (DT The) (NN term) (JJ ecological) (NN succession)) (VP (VBZ refers) (PP (TO to) (NP (NP (DT the) (NN sequence)) (PP (IN of) (NP (NN community) (CC and) (NN ecosystem) (NNS changes))))) (PP (IN after) (NP (DT a) (NN disturbance)))) (. .)))