What Is Macroevolution? In science, macro at the beginning of a word just means "big", and micro at the beginning of a word just means "small" (both from the Greek words). In evolutionary biology today, macroevolution is used to refer to any evolutionary change at or above the level of species. It means the splitting of a species into two or the change of a species over time into another. Any changes that occur at higher levels, such as the evolution of new families, phyla or genera, is also therefore macroevolution, but the term is not restricted to the origin of those higher taxa. Microevolution refers