Process of speciation in Darwinian theory of evolution

Explain the process of speciation in terms of the Darwinian theory of evolution by  natural selection and apply it to examples of three patterns of speciation taken  from primate evolution. See the online notes for the patterns and processes of  speciation.
Your essay should be approximately 500-700 words in length. And please follow essay guidelines mentioned in essay Guidelines file and add text citations to it.