Everything changed, however, with the arrival of the human species.  Since the first human being, the number of species going extinct has remained high while the number of new species appearing measures a virtual zero.  Estimates of the current rate of extinction vary, from a low of one species per day to a height of five species per hour.  Though many believe that the influence of the human race on that rate predominates, environmental experts are willing to say that even if no humans existed, at least one species per year would still go extinct.  Meanwhile, as biologists Paul and Anne Ehrlich disclose, “The production of a new animal species in nature has yet to be documented.”  Furthermore, “in the vast majority of cases, the rate of change is so slow that it has not even been possible to detect an increase in the amount of differentiation.”  Obviously, a tremendous imbalance between extinctions and speciation now exists.