Are humans only one species or Africans, Asians, Europeans, Mongolians etc are different species? They differ drastically in appearance.
There is only one human species today, although there were more in prehistoric times. Whether they differ in appearance "drastically" is a subjective opinion, but maybe you are looking for a different term? Someone indigenous to Europe and Asia may have slightly different features, but they are not as physiologically distinct as, say, apes and orangutangs.