( Microevolution ( ( ( occurs ( over ( ( a ( ( relatively short ) period ) ) ( of time ) ) ) ) ( within ( ( ( a population ) or ) species ) ) ) . ) )
(ROOT (S (NP (NNP Microevolution)) (VP (VBZ occurs) (PP (IN over) (NP (NP (DT a) (ADJP (RB relatively) (JJ short)) (NN period)) (PP (IN of) (NP (NN time))))) (PP (IN within) (NP (NP (DT a) (NN population)) (CC or) (NP (NNS species))))) (. .)))
Microevolution occurs over a relatively short period of time within a population or species.
(ROOT (S (NP (NP (NNP Evolution)) (SBAR (WHNP (WDT that)) (S (VP (VBZ occurs) (PP (IN over) (NP (NP (DT a) (JJ short) (NN period)) (PP (IN of) (NP (NN time))))))))) (VP (VBZ is) (VP (VBN known) (PP (IN as) (NP (NN microevolution))))) (. .)))