evolution of mankind

Evolution:A process in which something passes by degrees to a different stage (especially a more advanced or mature stage); "the development of his ideas took many years"; "the evolution of Greek civilization"; "the slow development of her skill as a writer" (synonym) development Useful information:
QUESTION: I have been puzzled for quite a few years now regarding the evolution of mankind. My understanding was Nabi Adam had 2 sons. How did the whole human race evolve from there on?. And if he had daughthers, does that mean brother and sister consumed to have a child. I am sure that there is rational explaination for the above that is in line with Islamic Teachings.
ANSWER: According to most reports, Allah (SWT) sent some fairies in human form to the sons of Nabi Adam to help in the procreation process. And Allah knows better. See Qisas al-Anbiya, Stories from the Qur'an, Islamic Seminary; page 18