In a March 26, 1999 issue of Science G. A. Clark contributed an article entitled Highly Visible, Curiously Intangible, subtitled modern human origins research. This article tackles the issues surrounding the two competing models of human evolution: the continuity model and the replacement model. Clark borrowed the title from the geneticist Henry Harpending's phrase-"a highly visible, yet intangible field," which Harpeding used to describe the controversial endeavor to trace the modern human origins. Clark states that until scientists make explicit paradigms for both replacement and continuity models, each model supporter camp will interpret common variables differently, to make them "fit" each respective model. Clark (1999) wrote, "We are, in effect, consumers of one another's research conclusions, but we select among alternative sets of research conclusions in accordance with our biases and preconceptions. These biases and preconceptions must be subjected to critical scrutiny. As long as there is no explicit concern with the logic of inference-how we know what we think we know about the past-there can be no consensus" (Clark, 1999, p. 2029). This paper will trace the origins of hominids, from the 4.4 mya Australopithecine period to the 100 tya Homo sapien period. It will side with the multiregional continuity model of hominid evolution, however, several sittings from works that support the replacement model will be incorporated into this paper in order to compare and contrast the significant differences in the two models.
             Most experts in the field of anthropology agree that the first erect bipeds, called the early hominids appeared in East Africa about four million years ago. They were given the name Australopithecus-being very primitive hominids, with small craniums and elongated arms, they were not known to have used fire or made tools. Researchers are aware of a few species o...