Currently, there are two hypotheses to the problem. First, the process of evolving from primitive to modern human involved a long period of time and nothing happened 100-200 thousand years ago. Second, there was a discrete event that caused a bottleneck in human population and stimulated genetic coalescence. Weaver (2012) showed how the lengthy process theory could explain current biological evidence that support the discrete event model. According to Weaver (2012) even without a discrete event, a coalescene would happened at the same time with a constant population, human would be expected to appeared about 200,000-100,000 years ago. After modern human appeared, they began to spread out the world. There are four models of the ways human moved out from Africa: the Eastward expansion (EE), multiple dispersal (MD), multiple dispersal with isolation (MDI), and “beachcomber” single dispersal (BSD) (Reyes-Centino et al., 2013). Eventhough, there no obvious evidence that could show the truth, but by analytical approaches, Reyes-Centeno et al. (2013) created a reasonable hypothesis that is human first migrated from Africa to north then another dispersal happened that they followed the southern route to Asia, so that means Reyes-Centino et al. support the MDI model by using differentiations in genetics and cranial phenotypes corelate …show more content…
By the study of human evolution, we support the evolutionism, and we will know soon what is the truth about human and all the living things on Earth. Furthermore, this study has potential in genetic science, psychology, and behavioral science. One of the most important reason that I picked this topic is because I think somehow this topic relates to me and my life in the US. According to the theory of evolution, all the creatures continuously change their abilities, shapes, and behaviors to adapt to the change of their surrounding environment in order to survive. The samething applies to me. Since I was born, there were two milestones that has shaped my thinking and helped me to became more mature, that were the time my family moved to the United States, and the time I went to SJSU. At the moment I put my first step in the US, I consider it a multi cultural country. That means there are something I have to change to blend in this environment such as learning new language, different time zone, eating habit, etc. For example, I have to eat fast foods even though they are not my taste; I learned to respect others’ culture; I learned not to stereotype and identify people base on their race,