Answer:
the phenomenon of REPRODUCTION and Evolution with acquired characteristics best describes the progression in the formation of these new species.
Step-by-step explanation:
As there were previously no mammal species on that island so the reproduced and fertilized with each other to produce new offspring.
and in the evolutionary view of life , evolution leaves observable signs.the populations of individual species become better adapted to their local environments through natural selection.these eight species progressed with evolution that fitted them best to their environment so they reproduced and survived.