Without evolution and constant environmental change, the complexity of living organisms would not be what it is. Evolution is defined as a process that causes heritable changes in a population spread over many generations (8). Scientists believe in the theory of evolution. This belief is based on scientific evidence that supports the theory of evolution. In Figure 1 the skull images depict the sequence of Homo-sapiens evolution. As the figure shows, humans evolved from our common ancestor shared by homo-sapiens. It is believed that the change in the diet of homo-sapiens over time contributed to the change in the structure of the jaw and the general shape of the skull. The process of evolution involves many complex mechanisms. These mechanisms fundamentally enable the progression of speciation and adaptation. There are 4 common types of evolutionary mechanisms of change: natural selection, genetic drift, mutation, and migration. Natural selection is based on the concept of "survival of the fittest" in which the most favorable individual and best suited to the environment survives and passes on its genes. for the next generation. Individuals less suited to the environment will die. Another heritable mechanism of evolution is mutations. Mutations are alterations to a gene. The mutation can be harmful, beneficial or neutral. Mutations are at the root of the source of genetic diversity (9). Harmful mutations hinder the organism's chances of survival and risk dying along with the mutations. Beneficial mutations increase the individual's chances of surviving in their environment, and they will be more likely to reproduce and pass the gene on to future generations (9).Migr...... middle of paper...... ley .edu/evosite/evo101/IIIADescent.shtml (12)Migration (03/31/14) https://www.blackwellpublishing.com/ridley/az/Migration.asp (13) http://www.ndsu. edu/pubweb/~mcclean/plsc431/popgen/popgen4.htm (14)Genetic Drift (03/31/14) http://www.wisegeek.com/what-is-genetic-drift.htm (15) http: //www.nature.com/scitable/definition/random-genetic-drift-genetic-drift-201 (16)Lamarck's Legacy http://lamarcksevolution.com/evolution-an-introduction/ (17) http:// evolution .berkeley.edu/evolibrary/article/history_09( 19)Vestigial organs http://www.factofun.com/top-10-vestigial-organs-human-body/ (18)MRSA http://evolution.berkeley. edu /evolibrary/news/080401_mrsa http://www.myvmc.com/diseases/methicillin-sensitive-staphylococcus-aureus-mrsa-staph-infection/(22)Theory of acquired inheritance http://necsi.edu/projects /evolution /lamarck/lamarck/lamarck_lamarck.html (20)