Part 3, Chapter 15 Summary

Darwin had many questions but no answers. He knew blood was the key to explain variations. He also knew variations were the origin of evolution. He just had no way of getting the proof during his life time.

Peter Boag still works with the Grants and the finches, but he now does it from a laboratory. He takes blood samples from the finches and extracts the DNA, then gives the DNA to the Grants for their research. The DNA between ground finches and tree finches are different, but the DNA is forever changing. Boag and his post-graduate helper, Hans Gelter, have been working with the Grants' finch blood for years and hope to one day figure out which finch started the different species on the Galapagos.

DNA has an SOS response in times of stress to reevaluate and change itself to...