Speciation (the creation of new species) is actually not that hard. It is particularly common among plants and insects. But that doesn't say much. All it takes to create a new species is one barrier that prevent successful mating between two parts of a species be it physical distance, a new variation on the mating ritual, one mutated enzyme in the reproductive system, or even an accidental change in the way its DNA is packaged into chromosomes and a new species is formed. But these species add very little to the diversity of life on the planet. It takes time, thousands of years of it to produce even small changes between such separated populations.
