Forensics is the branch of science that uses evidence found in the present to speculate upon what might have happened in the past. Like the investigation of a crime scene, the further in time back the occurrence took place, the less evidence of the event is likely to remain. Evolution is a speculation of what happened millions of years ago based upon fossils found in the present. Jerry Bergman starts his evaluation of fossils based upon two complex features commonly found: teeth and feathers.