( and ( ( populations ( in ecosystems ) ) ( ( are ( ( limited ( by ( ( ( ( ( the availability ) ( of ( ( matter and ) energy ) ) ) , ) and ) ( ( the ability ) ( of ( the ecosystem ) ) ) ) ) ) ( to ( recycle materials ) ) ) ) . ) ) )
(ROOT (S (CC and) (NP (NP (NNS populations)) (PP (IN in) (NP (NNS ecosystems)))) (VP (VBP are) (VP (VBN limited) (PP (IN by) (NP (NP (NP (DT the) (NN availability)) (PP (IN of) (NP (NN matter) (CC and) (NN energy)))) (, ,) (CC and) (NP (NP (DT the) (NN ability)) (PP (IN of) (NP (DT the) (NN ecosystem)))))) (S (VP (TO to) (VP (VB recycle) (NP (NNS materials))))))) (. .)))
and populations in ecosystems are limited by the availability of matter and energy, and the ability of the ecosystem to recycle materials.
(ROOT (S (PP (IN Unlike) (NP (NN energy))) (, ,) (NP (NN matter)) (VP (VBZ does) (RB n't) (VP (VB need) (S (VP (TO to) (VP (VB be) (VP (ADVP (RB constantly)) (VBN added) (PP (TO to) (NP (NNS ecosystems))))))) (SBAR (IN because) (S (NP (PRP it)) (VP (VBZ is) (VP (VBN recycled) (PP (IN through) (NP (NNS ecosystems))))))))) (. .)))