From stackexchange.biology Evolution in 37 Years, is it possible?Evolution in 37 Years, is it possible? is quite an example for this question. It investigates the speciation of two lizard groups in 37 years:
In 1971, biologists moved five adult pairs of Italian wall lizards from their home island of Pod Kopiste, in the South Adriatic Sea, to the neighboring island of Pod Mrcaru. Now, an international team of researchers has shown that introducing these small, green-backed lizards, Podarcis sicula, to a new environment caused them to undergo rapid and large-scale evolutionary changes."