During the last 30 years Paleoantrhopology has undergone a series of conceptual and methodological transformations. The discoveries of new fossils and the birth of Molecular Anthropology have been the main factors responsible for such changes. However, the identification of species and the establishment of phylogenetic relationships among them continue to be, as the were originally in this field of study, the fundamental tasks. These tasks on seem to be obstructed by a series of old technical, methodological, and conceptual preconceptions, that refer to the place which man occupies in nature, and to a Hierarchcal visionof diversity.En este trabajo se discuten y plantean algunos cuestionamientos acerca de la evolución humana usando algunos términos de la antropología física y otras disciplinas a fin, también se pretende explicar como esta disciplina define a la paleoantropología y en que se basa para ello.