All the evidence points to the fact that absolutely all organisms, including man, are descended from a single common ancestor. The evidence is so good. Ironically, the fossil record of human evolution is one of the best, most complete, and ironclad documented examples of evolutionary history that we have assembled in 200 years or so of Paleontological research. Creationist attempts to punch holes in this incredibly well documented history of human evolution are simply wimpy. Apparently it is easier to show the connections between our own species and the living apes and fossil humanoids than it is to show connections between the major divisions of the ancient trilobites.
Many branches become extinct in time, as has happened in human evolution.
Many of the fossil finds do not branch to us. A number of human genes deal especially with the brain. According to evolutionary studies all races belong to the same species with shared genes. The more variation in a species the better it is able to survive. The human species contain substantial reservoirs of genetic variation that can be tapped under new conditions of environment.