You remember the bar shading from black to white. I want you to tell me at what exact point along its length the bar turns white. "I thought it would be simple."
The difficulty of answering such questions is a prediction of the theory of evolution. Speciation is a continuum, not a break. Remember, every creature is only minutely distinguishable from its parents. Creationists on the other hand think that it should be easy to distinguish non-human fossil hominids from human fossil hominids, yet all the different creationist sources disagree on the major fossil hominid finds.
Are you saying science cannot define "human"?