Part 2, Chapter 11 Summary

Darwin did not believe hybrids created new species. It may have helped the process, but natural selection had already started. Even though he used the knowledge of many breeders for information for "The Origin," he did not think hybridization played a significant role in evolution.

Raymond Pearl, a geneticist from America believed as Darwin; however, after much research and discussion with breeders, Pearl ended up believing that hybridization played a more significant role in evolution than did natural selection.

The Grants have seen from their own research that not only is natural selection and hybridization equally important, but that they work together to cause evolutionary changes in races.

The Grants have seen two types of boundaries that affect Darwin's finches. One is the boundary of the island. The other is the boundary of the species. The species' boundaries are evident during...