Short video that explains the basics of natural selection and evolution. 

PBS has a great website that provides information about the basic concepts in natural selection, Charles Darwin and evolution (Link).

The website, 23andme.com, has some great tutorial videos and educational resources about genetics (link) 

If you are interested in reading a very good book about the history of IQ tests and Eugenics, I highly recommend this book: The Mismeasure of Man by Stephen Jay Gould. (link)