Video 1 - Mutations (this video goes into more detail than you are expected to know, but provides a good overview of mutations)
Video 2 - Natural Selection (this video explains the premise of natural selection and how, over time, it results in evolution)
Video 3 - Adaptive Radiation (this video explains a bit more about the Galapagos finches and how adaptive radiation led to the development of many species from one single original species)
Video 4 - Artifical Selection or Selective Breeding