( ( Assortative mating ) ( ( may ( be ( ( ( required ( for ( sympatric speciation ) ) ) , ) ( ( meaning ( ( the evolution ) ( of ( a ( new species ) ) ) ) ) ( without ( geographic isolation ) ) ) ) ) ) . ) )
(ROOT (S (NP (JJ Assortative) (NN mating)) (VP (MD may) (VP (VB be) (VP (VBN required) (PP (IN for) (NP (JJ sympatric) (NN speciation))) (, ,) (S (VP (VBG meaning) (NP (NP (DT the) (NN evolution)) (PP (IN of) (NP (DT a) (JJ new) (NN species)))) (PP (IN without) (NP (JJ geographic) (NN isolation)))))))) (. .)))
Assortative mating may be required for sympatric speciation, meaning the evolution of a new species without geographic isolation.
(ROOT (S (NP (JJ Sympatric) (NN speciation)) (VP (VBZ is) (SBAR (WHADVP (WRB when)) (S (NP (DT a) (JJ new) (NN species)) (VP (VBZ arises) (PP (IN without) (NP (JJ geographic) (NN separation))))))) (. .)))